PLEASE NOTE: THIS PROJECT IS NOT SCIENTIFIC. IT IS A HOBBY.
"I was looking for information on an old mammal and found this lot. What is this
project?"
It's got lots of information on old mammals. For a short bit of background information, see
here.
This directory features multituberculates which
are mostly post-Mesozoic; the products of a post Cretaceous radiation.
As an exercise in book-keeping, this directory has been one of the most challenging. In
terms of internet material, however, it's somewhat impoverished. There are plenty of fossil
inventories on North American locations, but readable articles and pictures are unfortunately
rare. There has been some improvement over the last year, but more would be welcome.
This directory was originally entitled Cimolodontidae and Ptilodontidae. Neoplagiaulacinae
and Ptilodontinae were treated as subfamilies of the latter. |
A. Neoplagiaulacidae & Neoliotomus B.
Ptilodontidae C. Cimolodontidae
| A. NEOPLAGIAULACIDAE & NEOLIOTOMUS |
| Taxon: Neoplagiaulacidae Ameghino F, 1890
Reference: Ameghino (1890), Los plagiaulácidos Argentinos y sus relaciones zoológicas,
geológicas y geográficas. Boletin del Instituto Geográfico Argentino, 11, p.143-208.
The following is based upon my reading of the text from Scott, 2005. Any page numbers
mentioned are in Roman numerals, and these don't correspond at all with those in the original
publication.
Neoplagis were relatively late multituberculates which flourished in the Paleocene (p.i).,
and then at least largely died out by the Eocene. (Rare Oligocene occurrences are sometimes
cited.) Most remains are poorly preserved fossils from North America, and poor preservation
means sorting out this from that can be difficult to impossible. For example, the species
rich genus of Neoplagiaulax probably contains various
neoplagis which, although broadly similar as far as they're known, don't all belong in the
same genus. Recognising that is relatively straightforward. Finding reliable characters
to resolve the tangle is a different matter.
Despite being among the latest multis, the family persevered with some ptilodontoid
plesiomorphies. Various groups of multis developed an
unusual mammalian tooth enamel organised into large prisms. In contrast, neoplagis
persisted with microprismatic enamel. The lower incisor
was thin and pointed forwards. The lower p4 premolar was
large and equipped with many cusps. In some ways these were traditionalists with little
appetite for innovations to exploit new resources, and this was in contrast to more
adventurous relatives; eg. taeniolabids.
They may not have been followers of the latest fashions, but neoplagis were far from old
hat. They were numerous in terms of individuals and species, and they out-survived
multi-modernists. As their demise appears to coincide with the rise of
placental rodents with presumably similar tastes, that
may well explain their downfall.
Difficult conservatives
Neoplagis were a dentally conservative bunch, as they don't display all too much refinement
of the inherited equipment (p.xxvi). This creates problems for distinguishing them from
one another, especially when only isolated remains are available. For example, there's
little difference between the upper molars of
Neoplagiaulax serrator and N. hunteri. In the
absence of further evidence, upper molars could sensibly be assigned to other species.
Those of N. serrator would also qualify for Ectopodys
powelli (based on differing criteria). It's the fourth premolars (both upper and lower)
which provide more clarity, and most especially the lower one.
Additional notes
Neoplagiaulacinae Ameghino, 1890 has been seen
as a sub-family within Ptilodontidae Cope, 1887, (McKenna & Bell, 1997). More recent
thinking has it as a family. Synonyms are Ectypodidae Sloan & Van Valen, 1965 and
Ectypodontidae Sloan & Van Valen, 1965.
At this juncture, you might like to consult a Welsh telephone directory. It'll contain many
names, a great number of which will be Jones. This section's a bit similar. Many names for
teeth, some of which have been classified, re-classified and re-re-classified, etc. The
exact affinities of Neoliotomus are not clear. It doesn't seem to be part of this
taxon, though it's thought to fit somewhere within
Ptilodontoidea. Somewhat uncertain are the affinities of a genus published in 2003,
Fractinus. I placed it here because it has some reported similarity with
Xanclomys. As Scott, 2005 includes it in the family, it appears I was right to do
so.
Genera: Cernaysia, Charlesmooria (= Ectypodus),
Ectypodus (partly = Neoplagiaulax &
Parectypodus), Eucosmodon (partly = Neoliotomus),
Fractinus, Krauseia,
Mesodma, Mesodmops,
Mimetodon, Neoliotomus,
Neoplagiaulax, Parectypodus,
Xanclomys, Xyronomys,
other reports
Time-Line:
Eocene: Ectypodus, Mesodmops, Neoliotomus, Parectypodus
Paleocene: Cernaysia, Ectypodus, Fractinus, Mesodma,
Mimetodon, Neoliotomus, Neoplagiaulax, Parectypodus,
Xanclomys, Xyronomys
Upper Cretaceous: Mesodma |
| Genus: Cernaysia Vianey-Liaud
M, 1986
'from Cernay'
Aka: Carnaysia |
| Species: | Cernaysia davidi Vianey-Liaud M, 1986 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Cernaysia manueli Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Upper Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Genus: Ectypodus Matthew WD
& Granger W, 1921
Aka: Charlesmooria ('for Charles Moor') Kühne, 1969; Parectypodus (partly)
Remarks: Messy. McKenna & Bell (1997) cites material from the Paleocene and
Eocene of Europe. According to Smith & Smith, 2004, the genus occurs in Ypresian
strata in France. Additionally, the original remains used for the establishment
of C. childei were found near London.
Reference: Matthew & Granger (1921), New genera of Paleocene mammals. American Museum
Novitates, 13, p.1-7.
| Reassigned species: ?E. aphronorus Sloan, 1987 see
Parectypodus sylviae; E. cochranensis Russell, 1967 see
Anconodon cochranensis; E.? grangeri
Simpson, 1935 see Neoplagiaulax grangeri;
E. hazeni Jepsen, 1940 see Neoplagiaulax
hazeni; cf. E. haueni (Jepsen, 1940) see
Ptilodus gnomus; E. hunteri Simpson, 1936 see
Neoplagiaulax hunteri; E. laytoni
Jepsen, 1940 see Parectypodus laytoni; E.
macrotomeus Wilson, 1956 see Neoplagiaulax
macrotomeus; E. russelli Simpson, 1935 see
Anconodon cochranensis; E.? silberlingi Simpson, 1935 see
Mimetodon silberlingi; E. simpsoni Jepsen,
1940 see Parectypodus simpsoni; E.
sinclairi Simpson, 1935 see Parectypodus
sinclairi; E. sloani see Parectypodus
sloani; E. sylviae Rigby, 1980 see
Parectypodus sylviae | |
| Species: | Ectypodus musculus Matthew WD & Granger, 1921
|
| Place: | Mason Pocket, Colorado |
| Country: | USA |
| Age: | Torrejonian, Upper Paleocene |
| Remarks: | A macho version, weighing in at around 30g. |
| Reference: | Matthew & Granger (1921), New genera of Paleocene mammals.
American Museum Novitates, 13, p.1-7. |
| Species: | Ectypodus powelli Jepsen GL, 1940 |
| Place: | Princeton Quarry, Wyoming |
| Country: | USA |
| Age: | Torrejonian-Tiffanian, Middle-Upper Paleocene |
| Remarks: |
Holotype and other specimens at the Peabody, Yale. At least some
of this material has been referred to Microcosmodon conus Jepsen, 1930. Guestimate,
20g. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Proceedings of the American Philosophical Society, 83, p.217-340. |
| Species: | Ectypodus tardus (Jepsen GL, 1930) McKenna MC,
1960 |
| Aka: | Parectypodus tardus Jepsen, 1930 |
| Place: | Colorado & Wyoming |
| Country: | USA |
| Age: | Wasatchian, Eocene |
| Remarks: | A descendant of E. powelli, (Burkitt JH).
Specimens presently studying at Yale University. Weighed about 15g. |
| References: | Jepsen (1930), New vertebrate fossils from the lower Eocene
of the Bighorn Basin, Wyoming. Proceedings of the American Philosophical Society, 69,
p.117-131. |
| McKenna (1960), Fossil Mammalia from the early Wasatchian Four
Mile Fauna, Eocene of northwest Colorado, Univ. Calif. Pub. Geol. Sci. 37 (1), p.1-130.
|
| Species: | Ectypodus lovei (Sloan RE, 1966) Krishtlaka &
Black, 1975 |
| Aka: | Parectypodus lovei Sloan RE, 1966 |
| Place: | Saskatchewan & Wyoming |
| Country: | Canada & USA |
| Age: | Uintan-Chadronian, Upper Eocene |
| Remarks: | Weight circa 15g. |
| Reference: | |
| Species: | Ectypodus szalayi Sloan RE, 1981 |
| Place: | New Mexico & Gidley Quarry, Montana &
Wyoming |
| Country: | USA |
| Age: | Mid Paleocene |
| Remarks: | 15g of furry fun.
Similar fossils have been identified in the Alberta locations of
Who Nose? and Cochrane 1 (though the latter is
undescribed). The first mentioned site has yielded two lower
premolars, (p4s). Their crowns contain eleven serrations. These specimens have been
referred to cf. E szalayi, (Scott 2003, p.747). |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates
from the San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan
Basin paleontology. University of New Mexico Press, Alberquerque. |
| Species: | Ectypodus childei (Kühne WB, 1969) Krause
DW, 1982 |
| Aka: | Charlesmooria childei Kühne, 1969; Parectypodus
childei Sloan, 1981 |
| Place: | Abbey Wood, London & ?Wyoming |
| Country: | England & ?USA |
| Age: | Wasatchian, Eocene |
| Remarks: | The following is based upon my reading of
Kühne, 1969, and more thanks fly to the dedicated supplier. The study included the
establishment of Charlesmooria childei. I don't happen to have seen the
relevant papers by either Sloan or Krause.
Fossils Kühne assigned to Charlesmooria were confined to a right lower incisor
and one p4 premolar, and it may be thought that establishing a
taxon upon such a limited basis was rather hasty. That seems to have been the
view of the author. He considered this: "the bare minimum for a diagnosis", and
proceeded "reluctantly". This occurred due to: "bitter experience regarding 'Duchy
33'". If all you had available were the original description, then the meaning of
that could be baffling.
Some decoding and UK slang is called for
The background gen is that Kühne had earlier been gazumped. That fine piece of
slang pertains to the complex and stressful activity of house buying. The seller
and wannabe purchaser generally aren't entirely open in their communication, and
neither knows the full story from both perspectives. Finally, however, a provisional
agreement is reached. But, before pen can be set to paper to consummate the matter,
the vendor suddenly pulls out of the deal for unexplained reasons. The wannabe
purchaser is left smelling something fishy, and it is indeed a rat. They've very
likely just been gezumped. Somebody else put the spoiler on things be offering ten
grand more. Regardless of any pledges of eternal love and longing, the vendor leapt
into bed with them behind your back. You're left standing alone at the altar, your
bridal bouquet develops brewer's droop and suddenly you: "ain't got no home" (with
thanks to Guthrie, W).
Kühne had been gezumped in the Lower Jurassic of South Wales. There, he'd found a
single tooth from an unknown genus of mammal, and
felt naming it should wait until later. More fossils would presumably come to light,
and provide fuller information. That'd be the time to name names, and Duchy 33 was
fine for the while. Paleontological names are meant to be useful, not ornamental.
However, somebody else failed either to respect or appreciate the situation, or
perhaps both, and published the name of Kuehneon.
As it happens, the only known specimen has since gone astray. The so "honoured"
Professor Kühne appears to have been left spitting blood in fury, and he sure as
hell didn't intend being gezumped in the Eocene near London.
Needles in a haystack in the wood
The since abolished Greater London Council had responsibility for managing Abbey
Wood, and this place happens to have included a fossil locality dating from the
Lower Eocene (p.199). Its ancient fauna included molluscs and
vertebrates; typical Londoners such as fish,
turtles, a crocodile and a primate. Not much has since changed in the area. Today,
London remains a terrain covered by lush and varied tropical forest. Well, there
are some greenhouses at Kew. Anyway, the park authorities opened up access to Abbey
Wood after the Second World War, and fossil collectors and randy courting couples
were only too pleased to take advantage of the opportunities provided. Herr and
Frau Kühne were certainly among the first group for three days during September
1968, and no mention is given of the second group. The kind of fossil techniques
the Kühnes employed went slightly beyond scouring the surface of the ground, and
putting shells and scraps in an empty plastic (I happen to have some Eocene fossils
in front of me. These shells and scraps were picked up from a somewhat more
recent Eocene locality at Highcliffe, east of Bournemouth, and we collected them in
a leisurely manner a couple of months ago or, if you're reading this later,
earlier.)
The Kühne style wasn't in the least leisurely. They stripped the top soil from a
convenient place and then gathered up a little bit of sediment; less than half a
ton. They could see this stuff must've been interviewed previously on at least one
occasion, and any larger mammal fossils had already been removed. After applying a
process termed wet dressing, a water filled chip pan with a one centimetre mesh
came into play. That was used to sieve out stones and unwanted oysters (p.200) and,
submerged under water, a half cm meshed sieve allowed for the removal of soil and
sand. Somehow, they found time to work through the whole heap during their brief
visit, and reduced things down to a more portable 75 kilos of mostly mollusc.
Returning with it to Berlin, they then resorted to chemical warfare. A particular
acid dissolved the mollusc remains, and other groovy attacks separated out flint
and persistent sand. Those activities brought things done to a single kilo; half a
sugar bag in weight subdivided into four categories of size. All that was then
examined with the help of a microscope and vast reserves of patience, and a grand
total of six mammal teeth were found among the 0.8 to 2mm stuff. That was the sum
total, a 3-3 draw between multituberculates
and primates.
Kühne style fossil hunting went beyond established frontiers.
The marks of this beast
The p4 premolar is rather small at only 2.9mm long,
and its crown features eleven serrations. There's a row of vestigial cuspules to the
rear on the lingual side. Its companion
incisor manages a preserved length of 3.5mm but, as
there's breakage, some is missing. That has enamel restricted to a band on the
front. Kühne allocated both to the family of Eucosmodontidae, as then understood.
The premolar was too small to be included into Liotomus marshi,
known from France. L. m. is over twice the length and features 15 to 17
serrations. It was also too small in comparison to known American cousins, in
Kühne's opinion. In comparison to L. m., the relatively low number of
serrations is said to show: "its evolutionary level is lower..." (p.201).
Presumably, that means it's more basal despite being
later. I fell like adding a 'perhaps'.
A small squeak from a once mighty choir
From the Upper Jurassic onwards, northern hemisphere mammalian faunas were often
dominated by multis in terms of numbers. They remained diverse during the Paleocene,
and some even explored the possibilities afforded by large,
beaver-sized formats; animals of 25 kilos and more. However, while not entirely
unknown, they were rarities in Eocene faunas, and none seem to have survived beyond
that age. Reported Oligocene occurrences have been proposed in North America, but
they more probably were misdated.
The efforts of the Kühnes were partly directed against a bias n the known record;
size-ism. Surface collection is all well and good, and can be fun, but it tends to
result in a distorted picture filled with too many biggling. Most the global
population happen to be small. The Kühnes also demonstrated suitable techniques can
drag new knowledge from localities, which have already been actively worked by
various people for several decades; even from previously sampled deposits.
What they also found was an extension of multis into the European Eocene. This was
only the second known source from the Tertiary in the continent. "It is hoped that
a third locality yielding Tertiary multituberculates may be discovered in Europe
soon" (p.202). Several have since been added, but I don't happen to have an
inventory.
RIP multis
A likely explanation for the extinction of multis remains competition from new
placental groups; firstly from "condylarths"
and then rodents. Kühne has a couple of observations pertinent to the second group
on page 201. Rodents have ever-growing incisors with open roots whereas multis
never hit upon such things. Multis were also limited by relatively thin tooth
enamel, although I don't know if that's still valid. (It is, as far as I'm aware.)
He also states multis: "never develop the tooth-sharpening modus known in most other
mammalia which R.G. Every has aptly called 'thegosis'." As far as I understand
thegosis, it refers to sharpening as a by-product of use.
Charlesmooria
This generic name honours the nineteenth century microfossil pioneer, Charles Moore
of Bath. His experiences, methods and successes earned him the title of: "the
spiritual father of the writer's activities in England and Wales from 1937 onwards.
As for the holotype, none was specified in the paper. The lower premolar is
clearly the more informative specimen, and would've been the logical choice. The
two fossils described were donated to the Natural History Museum, London, and a
small piece of an upper premolar provided them with company. The trio received the
catalogue numbers of M26617, -18 and -19. As for the specific name, that honours V
Gordon-Childe for his efforts to more archaeology more scientific in its approach.
Additional notes
I read somewhere or other that the species was found in Wyoming, but I don't
presently know whether that's correct. The type fossil is certainly from near
London.
The junior synonym, Parectypodus childei, was reportedly originally referred
to P. lunatus, a citizen of Colorado. A 15g titch. |
| Reference: | Kühne WG (1969), A multituberculate from the Eocene of
the London Basin, Proceedings of the Geol. Society of London, 1658, p.199-202. |
| Species: | Ectypodus aphronorus Sloan RE, 1987 |
| Place: | Gidley Quarry, Montana & Wyoming |
| Country: | USA |
| Age: | Middle Paleocene |
| Remarks: | I've heard this is possibly a junior synonym of
Parectypodus sylviae, which began its career as E.. Scott, 2005 suggests
it's nevertheless a valid species of this genus. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p. 165-200. In J. E. Fassett and J. K. Rigby Jr. (eds.),
The Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Species: | Ectypodus elaphus Scott CS, 2005 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
This is a small species of Ectypodus (p.iv). The length of the lower p4
premolar is half that of E. musculus and 23% less
than for E. powelli and E. aphronorus, and the crown is also relatively low
(compared to E. m. and E. a.). The most similarities are shared with E.
szalayi and E. tardus. Again though, the crown is lower and less symmetrical
when viewed from the side. The first serration is also set lower, and the front of the
crown is steeper. Additionally, both cusp rows on p4s of E. szalayi have more
cusps. The retention of a p3 tooth is a contrast from both E. tardus and E.
childei.
Upper premolars
Some uppers have been assigned to the species, and most are P4 premolars. The numbers in
the 'three' cusp rows (labial to
lingual) are given as: (0)2:6:0. A pair of strong cusps is positioned towards the
front of the labial side, the middle row runs in a straight line and an internal row is
absent. The front of the tooth is supported by a root with a circular cross-section, while
its rear partner looks more like it's been squashed from both sides; ie. it's laterally
compressed.
Upper molar
Only the M1 is known; cusp formula 7:9:5. In size and structure, this tooth is rather like
the generally earlier Mesodma pygmaea, although this version
is a bit bigger and the lingual cusp row is longer. The cusps of the central row are shaped
like pyramids rather than crescents.
Lower jaw
The type fossil (and several colleagues) provide information about the
dentary (p.v). The available material is much as could be expected for a neoplagi.
Towards the back, the coronoid process was presumably tall, and the condyle (the lower
element of the jaw-skull joint) was broad and oval in shape.
Lower premolars
The p3 is a pathetic thing which was granted sanctuary in a concave area at the base of the
p4; the sole lower premolar interested in working for a living.
Seen from the side, the crown of the p4 is of a moderate height, and the front and rear
slopes aren't as symmetrical as for other species of the genus. As well as the aforementioned
concavity, the front root is also grooved so as to provide room for the anterior premolar.
The crest of this tooth generally bears eleven serrations, although some specimens restrict
their enthusiasm to ten. These become larger and stronger progressively towards the rear.
Ridges run down both sides of the tooth from the serrations, and they become fainter. The
final serration has no such ridges.
Lower molars
The cusp formula of m1s is 8:4 (buccal -
lingual), and the outline of the crown is near to rectangular. The cusps rows drift
away from each other towards the rear, and a fairly deep valley lies between them. The
crescent-shaped buccal cusps are lower than the pyramid-shaped lingual ones. These
molars are very similar to those of E. tardus from the
Eocene (p.vi). They're also rather like the equivalent teeth of Mesodma pygmaeae,
but they're a bit longer and have at least two more buccal cusps.
The sole specimen of an m2 has a cusp formula of 4:2. It's also similar to Ectypodus
and Mesodma pygmaea, but it's a bit wider than the latter.
Affinities
E. elaphus seems most similar to E. szalayi in terms of the p4. The average
length is close (2.63 against 2.8mm respectively), and both forms favour eleven serrations.
The differences include the lower and less symmetrical crown for the new species.
The pair appear to be basal members of the genus, and they
also share features with more primitive neoplagis such as Mesodma
(p.vii). Although later, Scott concludes E. elaphus is possibly the less derived of
the duo.
Holotype
The type fossil, UAL VP 45994, studies at the University of Alberta, Edmonton. It's a
partial left dentary with premolars 3 and 4, and
alveoli for the incisor and two molars. 'Elaphos' is Greek for 'deer' and 'stag',
and this honours the city of Red Deer, which is close to the fossil locality. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Species: | ?Ectypodus clemensi |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Paleocene |
| Remarks: |
The Peabody, Yale has a cast of an E. cf. clemensi,
collected in 1977. Common sense suggests this is Krauseia clemensi. |
| Reference: | |
Genus: Fractinus Higgins P, 2003
'broken into pieces'
Remarks: The generic names refers to the locality, which is called The Breaks. |
| Species: | Fractinus palmorum Higgins P, 2003 |
| Place: |
The Breaks, Wyoming |
| Country: | USA |
| Age: | lower Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of
Higgins, 2003a.
The northeastern corner of the Hanna Basin contains an area of badlands known as The
Breaks, (p.468). So far, remains of 72 separate mammalian species have been identified
from the locality, but only this one has not already been described from elsewhere. 17
of these species are multis, but they account for over half of all the specimens, (426 out
of 811). This material is in the Collection of Fossil Vertebrates of the University of
Wyoming.
Hardly a mouth full
Remains are presently restricted to one and a bit teeth. These are the spectacular lower
premolars. However, they're unusual for multis. Unlike
the equivalents known from most members of Ptilodontidae, Cimolodontidae and
Eucosmodontidae, they don't have as many serrations on the cutting edge, (approximately
five). These are also more rounded than usual, and start further back. The
ptilodontoidean which is most similar is Xanclomys, and that's my logic for placing
the genus in this section. It isn't intended to say anything concerning the actual
affinities of this critter. However, it also differs from Xanclomys. It has less
serrations, and they're found in a single line. It seems to significantly differ from
everything in Multidom, though there is a superficial resemblance in shape to Jurassic
multis such as Psalodon. It was a middling-sized representative of the order.
Techniques for working this locality were mainly underwater screen-washing and surface
crawling, which sounds potential painful on the knees in a rugged landscape.
Holotype
The type fossil is a lower, left premolar (p4) with a length of slightly less than 5mm.
It's in the Wyoming collection and is affectionately known as UW 27063. It enjoys the
company of one other fragment of a p4, which was found about 25m away. The species name is
in honour of Burt and Kaylyn Palm, who kindly permitted access to these sites on their
property.
Additional notes
Scott, 2005 includes the genus within Neoplagiaulacidae (p.i). |
| Reference: | Higgins (2003), A New Species of Paleocene Multituberculate
(Mammalia: Allotheria) from the Hanna Basin, South-Central Wyoming. Journal of Vertebrate
Paleontology, 23 (2), p.468-470. |
| Genus: Krauseia Vianey-Liaud
M, 1986
'for Krause'
Aka: Parectypodus (partly)
Reference: Vianey-Liaud (1986), Les Multituberculés Thanétiens de France, et leurs
rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool. Stratigr.
191 p.85-171, 3 plates. |
| Species: | Krauseia clemensi (Sloan RE, 1981) Vianey-Liaud M,
1986 |
| Aka: | Parectypodus clemensi Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico &
Wyoming |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | An approximate weight for P. clemensi is
one standard mouse, 25g. |
| References: | Sloan (1981), Systematics of Paleocene multituberculates from
the San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan
Basin paleontology. University of New Mexico Press, Alberquerque. |
| Vianey-Liaud (1986), Les multituberculés Thanétians de France, et
leurs rapports avec les multituberculés Nord-Américains, Palaeontographica Abteilung A
Palaeozoologie-Stratigraphie, v.191, p.85-171. |
| Genus: Mesodma Jepsen
GL, 1940
Aka: Cimexomys (partly); Cimolodon (partly); Cimolomys (partly);
Halodon Marsh, 1889? (partly); Parectypodus (partly); Ptilodus
(partly)
Remarks: A variety of further material has been reported. This looks like a messy genus.
I’ll try to avoid confusing things further. A heap of unnamed specimens also crop up here
and there. I’ll ignore them until they’re properly introduced. One example is a lower
premolar (p4) from North Dakota, (Hunter & Pearson
1996, p.635-636): "The specimen is within the size range for p4 length of M.
thompsoni Clemens 1964, M. garfieldensis Archibald 1982 and M. ambigua
Jepsen 1940, although it would be unusually large for the first two species."
An early bird
A Santonian presence has been reported by Eaton JG, 2005, from the Straight Cliffs Formation
of Utah. This would be the oldest representative of the genus. The abstract is linked to
the entry for Cimolodon foxi.
Hell Creek, Montana
Lofgren, 1995 reports that something like 2,200 specimens of teeth and jaw fragments of this
genus have been recovered from the Hell Creek Formation (p.78). At the time, they hadn't
been referred to any particular species. His work is an examination of geological conditions
and mammal fossils from localities at Cretaceous-Paleocene,
McGuire Creek.
| Reassigned species: M.? ambigua? Jepsen, 1940 see
?Cimexomys gratus; M. silberlingi
see Mimetodon silberlingi | |
| Species: | Mesodma ambigua Jepsen GL, 1940 |
| Place: | Mantua Lentil, Wyoming, Montana &
Colorado |
| Country: | USA |
| Age: | Maastrichtian-Puercan, Upper Cretaceous-Paleocene |
| Remarks: | Descendant of M. thompsoni, (Burkitt, JH).
Material at Yale, where M.? a.? became ?Cimexomys gratus. They also have the
type fossil. Weighed about 55g, two slightly fat mice. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation, Park
County, Wyoming, Proceedings of the American Philosophical Society, 83(2), p.217-341. |
| Species: | Mesodma formosa (Marsh OC, 1889) Clemens, 1964a
|
| Aka: | Cimolomys formosus Osborn HF, 1891; Cimolomys gracilis
(Marsh, 1889) Simpson, 1929; Halodon formosus Marsh, 1889; M. formosus;
Ptilodus formosus Gidley, 1909 |
| Place: | Montana New Mexico, South Dakota, ?Utah,
Wyoming & Alberta, Saskatchewan |
| Country: | USA & Canada |
| Age: | Upper Cretaceous (Campanian - Maas.) - Paleocene (Puercan) |
| Remarks: | Osborn, 1893 (p.315) reveals that Halodon
formosus had been established for lower premolars (p4s). At the time, he referred the
species to Ptilodus, which is now restricted to the Paleocene. Marsh based
Cimolomys gracilis on upper molars (M1) (p.316). These have three rows of cusps
running along the complete length of the crown (p.317).
Additional notes
Possibly also Utah. The holotype is at Yale and
a suggested weight is a
fat-moused 30g. South Dakota is mentioned by Foote et al, 1999.
Some material which seems at least similar to this species has been recovered from the
El Gallo Formation of Mexico, (Weil 1999, p.87). |
| References: | Marsh (1889), Discovery of Cretaceous Mammalia. Am. J. Sci. (3)
xxxviii, p.177-180. |
| Osborn (1891); A review of the Cretaceous Mammalia. Proc. Acad. Nat. Sci.,
Phila.: 124 - 135. |
| Simpson (1929), American Mesozoic Mammalia. Mem. Peabody Mus. Nat. Hist. iii (i):
p.1-235. |
| Species: | Mesodma primaeva (Lambe, 1902) Clemens,
1964a |
| Aka: | Cimolomys primaevus Simpson, 1929; Mesodma
primaevus Clemens, 1963; Parectypodus primaeva;
Ptilodus primaevus Lambe, 1902 |
| Place: | Oldman Formation & Montana, Wyoming |
| Country: | Canada & USA |
| Age: | Campanian, Upper Cretaceous - Lower Paleocene |
| Remarks: | The following is largely based upon my
reading of Sahni, 1972, a study concerned with vertebrates from the Judith River
Formation of Montana.
A dimensions ditty
M. primaeva is about the same size as M. thompsoni (p.367), larger when
compared to M. formosa but gets beaten in this regard by M.
ambigua.
Lower incisors
Several referred several of these teeth to the species. They were the right size
and much like incisors identified previously.
Lower premolars
The average length of p4s from the Judith River Formation, was 3.0mm, and
the blade of the tooth has 11 serrations. On the labial
side short ridges are associated with the first two serrations, and they run towards
ridges descending from the others. The blade is high and nearly symmeticral, with
its highest point achieved by the fourth or fifth serration. A cavity is found at
the front of the tooth, and this provided housing for the pathetic p3. All cavity
walls are thickly enamelled excepting for the rear one.
Ridges also occur on the lingual face of the crown.
The first is longer than or equal to the second, and the longest ridge of all is
generally the fifth (although sometimes it's the fourth or sixth). The crown has
the support of two roots, with the first one being the larger (p.369).
Lower molars
There's a difficulty with isolated m1s, and that is differentiating them from the
corresponding teeth of Cimolomys clarki.
For both taxa, the sizes and cusp distribution happen
to be much the same. The length range of those available to Sahni ran from 3.15 -
3,6mm, and the cusp formula is 5-6 (labial) : 4 (lingual). For the first mentioned
row, one tooth has the foremost cusp as the smallest, and it's followed by crescentric
cusps with the curve pointing backwards; helpfully directing food towards the entrance
of the reception chute to the recycling department. The lingual brigade are higher
than their colleagues, more proudly erect, and the last but one is the largest. The
occlusal outline of the crown is rectangular. Roots
are widened rectangles in cross section with no accessory assistants.
As for m1s, referrals of m2 are also tentative. One specimen has a cusp formula
4:2, with the labial row reducing down to 3 for later
species of Mesodma. On that row, the first cusp is a cone and its followers
are more backwards pointing crescents. Taking advantage of the available space,
the pair of internal cusps luxuriate by being larger. A ridge runs across the
central valley from the first lingual to the second external cusp, as is typical for
other specimens, and the tooth length averages 2.4mm. The front root is a widened
rectangle.
Upper jaw and premolars
I don't know the origins of the name for Clambank Hollow Quarry, but being a quarry
with a bed of fossil clams in a hollow may have had a role to play. At, least,
there's certainly a clam bed 12 metres to the east, and it's been generous with
other fossils as well. One of these was the sole bit of multi jaw found during three
years of prospecting, and it proudly retained the second and third upper
premolars. It's probably from Mesodma,
based on similarities with material from elsewhere, although it could belong to
Cimexomys judithae.
P2 is a tri-cusped tooth of a somewhat loftier elevation than the following premolars.
A single cusp is labial from the other two. The front
of that pair is taller but thin, whereas the rear one is the larger of the trio.
Double-rooted, 1mm long, 0.7 wide.
P3 seems to be a bit lingually positioned in
comparison to P2, and has one more cusp; ie. two rows of two. The rear couple are
larger but wear was heavy, and many details are obscured. The size isn't much
different to P2: length 1mm, width 0.65, and it also has two roots.
The referral of P4 is put as 'tentative'. As these rear premolars were expected to
partake in some degree of grinding works, the furnishings are more complex than those
provided with their lazier, more forward colleagues. There are three cusp rows
(labial to lingual): 2:6:2. The second cusp of the labial row dominates its front
friend in terms of size. The cusps of the middle row make up a line of cones, the
fifth of which is the highest. As all this stuff requires space, the P4 is a
considerably larger premolar with a length of four millimetres.
Upper molars
A number of M1s were available, with lengths averaging four millimetres and widths
at two (p.370). There are three cusp rows (labial to lingual): 6:7:5. The external
cusps are cones to the front while the rear members show a more pyramid-shaped
tendency. Grooves scar the inner faces. The lingual cusp row gets fed up with life
a bit over the halfway line of the crown and peters out, but none of the five (or
sometimes six) are all that distinct; 'cuspules' wouldn't be an insult. Two features
are probably basal and aren't found in later species.
The numbers of cusps in the labial and middle rows is comparatively modest, whereas
the internal 'cuspules' later became more distinct and clearly separated. The crown
was ably supported by two roots, with the rear one being the widest.
As is to be expected for multis, M2 is a considerably smaller piece of work than its
partner; length 2.1mm, width 1.6. The cusp formula is 1:3:4. The sole
labial cusp sits on a ridge, and the three middle ones
are large and crescentric in shape. The four lingual cusps are well separated (in
contrast to their equivalents on M1), and the front one is joined by a ridge to the
leader of the middle mob.
Sahni notes that this species is suitable as the ancestral form for M. formosa
and M. thompsoni.
Holotype
NMC 1890 is part of a lower jaw in the care of the National Museum of Canada. It was
originally referred to Ptilodus, transferred to a loosely defined
Cimolomys in 1929 and then ushered into Mesodma by Clemens. That
mandible was kindly provided by the Near Steveville
locality, so thanks are due to Near Steve.
Additional notes
Matthew, 1916 (p.479) reports Lambe based the
species P. primaevus on a partial jaw with two teeth from Alberta. One of these was
a premolar.
Several specimens are at the AMNH, New York, where the name M. primaevus is
also used. That's the name Sahni used in 1972. At a guess, I'd imagine the different
ending results from the genders of Latin grammar. |
| References: | Lambe (1902), New genera and species of the Belly River
Series (Mid Cretaceous), p.79 in Osborn & Lambe (1902), Vertebrata of the
Mid-Cretaceous of the North West Territory, Contributions Ca. Pal., 30, Geological Survey
of Canada. |
| Simpson (1929), American Mesozoic Mammalia, Mem. Peabody
Mus. Nat. Hist., 3, pt. 1, xv+171 p. |
| Clemens (1963), Fossil mammals of the type Lance Formation,
Wyoming. Pt. 1. Introduction and Multituberculata, University of California
Publications, Geol. Sci., vol. 48, p.1-105, figs. 1-51. |
| Species: | Mesodma thompsoni Clemens WA, 1964 |
| Aka: | Cimolodon nitidus Marsh, 1889; Cimolomys gracilis (Marsh,
1889) Simpson, 1929; Cimolomys nitidus |
| Place: | Wyoming, Montana, New Mexico, North Dakota, South Dakota, Texas,
Utah? & Alberta, Saskatchewan |
| Country: | USA & Canada |
| Age: | Upper Cretaceous (Campanian - Maastrichtian) - Paleocene (Puercan) |
| Remarks: | The holotype, UCMP 47217, resides at the
University of California. It's a left lower premolar (p4).
This was recovered from Niobrara County, Wyoming. Subsequent finds include a left
dentary with p3 and p4. The latter tooth has 12 serrations
and is lower arched than known from M. formosa, (Hunter & Archibald 2002,
p.194).
The Saskatchewan material probably belongs to a separate species, but it hasn't yet been
renamed. Some further discussion is included in the article on French Fry, below.
A specimen at the Peabody has apparently been assigned to Cimolodon sp. and vice
versa! Weighed approximately 55g. I've seen the year 1963 given for this citation. |
| Reference: | Clemens (1964), Fossil mammals of the type Lance Formation
Wyoming. Part I. Introduction and Multituberculata. University of California Publications
in Geological Sciences, 48, p.1-105. |
| French Fry, after the dinos had their
chips
The following is based upon my reading of Fox, 2002.
One way or another, (or actually in a combination of ways), rocks record information
concerning how and when they were laid down. Much of geology centres upon understanding
such information but, as should be expected, there are complications. The short paper by
Fox gives insights into some, which apply to the Cretaceous-Tertiary transition on land in
North America; the K-T extinction(s) and all that.
As I'm writing this, then mammals self-evidently survived that transition, but discoveries
of remains which are unambiguously very near in time to those event(s) are hard to find,
(p.456). Though 100,000 years is short in terms of geological time, (and is usually of
little significance in Mesozoic research), it equates to about twenty times the length of
written history, 4,000 human generations and many more mouse-sized mammal ones. If you
want strata as close to 65 million years old as possible, things can get frustrating.
Sources of imprecision
In most cases, the relevant mammal fossils were deposited by stream and river action.
While many thousands of specimens have been found, these are generally jaw fragments and
less. Running water is destructive. Another complication is that water doesn't habitually
flow horizontally in thin air. River courses are bedded on, (and cut into), underlying
rock. Often in North America, this also happened to contain fossils. As there was erosion,
transportation and secondary deposit of already fossilized remains, things can be a bit
muddled. Fortunately, characteristic damage generally results from such processes, but
the presence of a few battered Cretaceous scraps in Paleocene sediments can be inconvenient.
Eastern Montana is particularly notorious for this.
A further problem is that it's not always possible to pin-point the K-T border. For example,
in the Ferris Formation
of Wyoming, it's located somewhere with an eight metre zone of uncertainty. Whether it's
high, middle or low in that zone is unclear, thus the uncertainty. The famous iridium
anomaly, informative floral changes, magnostratigraphic markers and radiometric dating all
presently refuse to cooperate there. Elsewhere, such markers may be obliging but
paleoconditions weren't conducive to the preservation of mammals.
I don't want to suggest vertebrate paleontologists aren't grateful for what remains are
available. As they, medical doctors and professional boxers could all tell you, the lower
jaw is the hardest bone in a mammalian body. That's why some of the above derive much
satisfaction from landing a punch bang on it. (Quibbling with a doctor over the details of
the bill can have unpleasant side effects.) Even so, it's amazing that fragments of jaw
can be preserved for tens of millions of years, (and hundreds of millions). Complaining
because it can't be worked out if the specimens are actually 64.99 million years old, rather
than about 64 million, would be showing ingratitude.
A relief road
Nevertheless, sympathetic Canadian road builders have done their best to help out with
unsatisfactory precision. A road called Route 37 provided a convenient cut into the
landscape of southwestern Saskatchewan, twenty miles or so south of the town of Shaunavon,
and this exposed a fossil site called French Fry. This pleasingly well behaved stratum sits
on top of what's known as the Ferris coal seam, which is an approximation of the K-T border
in the region. An unusual feature of this rock is that it's the result of lucristine
deposits rather than fluvial ones. Lake environments are usually less mischievous than the
more disruptive efforts produced by streams and rivers.
The Ferris coal seam is known to mark the K-T border due to a couple of independent
factors, (p.457). Firstly, most plants characteristic of the Cretaceous Woodhouseia
spinata assemblage disappear abruptly. Furthermore, the much cited iridium anomaly is
present at a similar level. The K-T border is located at the foot of the coal. Also
convenient are the side effects of change in the magnetic polarity of the planet. The K-T
transition occurred in the time of reversed polarity 29r. The rock section including French
Fry corresponds in that regard as well. It has a thickness of about thirty metres, and
about two-thirds is Cretaceous. Reversed polarity 29r lasted for about half-a-million
years.
Assuming regular rates of deposition, (which isn't necessarily the case), then each of the
thirty metres would represent approximately 16,700 years. (Information from elsewhere in
Canada suggests that, in appropriate conditions, lake sediments can accumulate considerably
more quickly, with a metre requiring two to three thousand years.) Even allowing for
uneven rates, any fossils originally laid down in the metre of rock above the K-T can
safely be called earliest Paleocene. This is precisely the position of French Fry.
Fauna
It would be nice if we could conclude with a broad list of clearly earliest Paleocene
mammals, as it's clear that the locality is within thousands of years', (not tens or
hundreds of thousands), proximity to the end of the Cretaceous. Presently, there's plenty
of scope for faunal enrichment. As it was a lake, most fossils are from various fish.
These are scales, vertebrae and teeth and are termed
'occasional'. Also known are rare remains of lizards called champosaurs. Mammalia is
presently represented by a well preserved, partial lower jaw of a multi. This is
Mesodma. The p4 premolar corresponds very closely
to remains from the Rav W-1 horizon of Saskatchewan, and these were referred to the species
of M. thompsoni. However, some subtle distinctions suggest this material
collectively represents a different species; perhaps a descendant. Establishing a new
taxon has been deferred until better material is available.
Fox explicitly states: "Therefore, the specimens from Rav W-1 and French Fry cannot
be cited as evidence that M. thompsoni survived into the Paleocene."
A short course in UK English for non-native speakers
'French Fry, after the dinos had their chips.'
French fries are chips, and American potato chips are properly known as crisps. After the
fat lady has sung and you're dead, you've had your chips. They're not just down. It was
finito.
Further Mesozoic site summaries can be found at Localities. |
| Species: | Mesodma hensleighi Lillegraven JA, 1969 |
| Place: | Montana, South Dakota, ?Utah,
Wyoming & Alberta,
Saskatchewan |
| Country: | USA & Canada |
| Age: | Campanian-Maastrichtian, Upper Cretaceous - Puercan, Paleocene |
| Remarks: | Another holotype in the Alberta University. A
furry 15g or about one-and-a-half standard
shrews. South
Dakota is mentioned in Foote et al, 1999.
The Paleocene material is from the
Ferris Formation of Wyoming. It gets a mention in Lillegraven & Eberle, 1999,
(p.702): "That range extension has the effect of increasing Archibald's (1996a)
calculated survival of Lancian species of
multituberculates into the Puercan from 50 percent to 60 percent." |
| Reference: | Lillegraven (1969), Latest Cretaceous mammals of the upper
part of Edmonton Formation of Alberta, Canada, and review of Marsupial-Placental dichotomy
in mammalian evolution. The University of Kansas Paleontological Contributions, 50,
p.1-122. |
| Species: | Mesodma senecta Fox, 1971 |
| Place: | Kalparowits Formation, Utah |
| Country: | USA |
| Age: | Campanian, Upper Cretaceous |
| Remarks: | Holotype at Alberta. Body mass of about two
mice, 50g. |
| Reference: | Fox (1971), Early Campanian multituberculates (Mammalia:
Allotheria) from the Upper Milk River Formation, Alberta. Canadian Journal of Earth
Sciences, 8 (8), p.916-938. |
| Species: | Mesodma garfieldensis Archibald JD, 1982 |
| Place: | Hells Hollow, Montana, Wyoming |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | Probable weight was around 40g. |
| Reference: | Archibald (1982), A study of Mammalia and geology across
the Cretaceous-Tertiary boundary in Garfield County, Montana. University of California
Publications in Geological Sciences, 122, p.1-286. |
| Species: | Mesodma pygmaea Sloan RE, 1987 |
| Place: | Gidley Quarry, Montana,
Wyoming &
Who Nose?, Alberta |
| Country: | USA & Canada |
| Age: | Torrejonian-Tiffanian, Middle Paleocene |
| Remarks: | Very pygmaea indeed, and weighed about 8g.
With regard to specimens, (teeth: -an upper premolar, P4,
and two lower p4s), from an excitingly named new site, Scott, 2003 (p.746) reports:
"The Nose Creek specimens are virtually identical in both qualitative and quantitative
characters to the type material from Gidley Quarry, Fort Union Formation, Montana (Sloan,
1987) and to specimens from Cochrane 2, Paskapoo Formation, Alberta (Youzwyshyn, 1988),
differing only in being slightly smaller and in having fewer serrations on p.4."
These examples, which are housed in the University of Alberta, have nine to ten serrations,
as well as a further incipient one, and provide the earliest evidence of this species in
western Canada.
|
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p.165-200 In Fassett JE & Rigby JK (eds.), The
Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Who Nose?, Calgary -Paleocene
The following is derived from my reading of Scott, 2003.
The Who Nose? locality is considered to be Upper Torrejonian (Paleocene), and is part of
the Paskapoo Formation. It's situated near the Calgary International Airport, and was
discovered in 1989 by Royal Tyrell Museum paleontologist, D Brinkman. Since then, it's
been worked by parties from the University of Alberta.
Calgary boasts a waterway called Nose Creek, which is fed by two branches; West Nose Creek
and North Nose Creek. The mammal locality lies a few hundred metres from the confluence of
them both, on the eastern bank of the west nostril. Quite who came up with the name Who
Nose? isn't explained. As well as the 400 mammalian specimens so far collected, (including
ten or so well-preserved jaws), various fragmentary remains of other critters have also
been recovered. These include fish, amphibians, lizards and crocodiles, (p.745-746).
New multis from the wider Paskapoo Formation
The following is based upon my reading of the text from Scott, 2005. Any page numbers
mentioned are in Roman numerals, and these don't correspond at all with those in the
original publication.
"Neoplagiaulacid multituberculates are among the most numerous and best represented
members of early Cenozoic North American mammal faunas, achieving their greatest diversity
during the Paleocene" (p.i). The Paskapoo Formation seems keen to emphasize this, as
Scott was able to launch four more species; Ectopodus elaphus,
Neoplagiaulax serrator, N. paskapooensis and
N. cimolodontoides. (For clarity, these are not from the Who Nose? locality.) These
are based on some relatively good specimens by North American Paleocene standards, as many
multi taxa saw fit to bequeath little more than isolated
teeth. All the new Albertans kindly included both upper and lower jaw material, and one
(N. cimolodontoides) also agreed to help with information on tooth replacement.
Meet the Formation
Paskapoo is from the Cree language and means 'blind man' (p.ii). I can't see why somewhere
should be named that, so perhaps they were referring to me. The Formation was deposited
along the east of what are now the Rocky Mountains, and outcrops can be found along the
Blindman and Red Deer Rivers of central and southern Alberta. It overlies the Scollard
Formation and must be younger. The main agent involved was river action, and this produced
a considerable number of fossil yielding localities. In terms of North American Land Mammal
Ages, the presence of Plesiadapis rex suggests a middle Tiffanian age (Ti3), which
makes it about contemporary with the Ravenscrag Formation (p.iii).
An intriguing aspect of the mammalian fauna in the Formation, is the wealth of species for
several multituberculates, and all are found at the same stratigraphic level (p.xxvii).
There are perhaps five species of Neoplagiaulax; N. serrator, N.
paskapooensis, N. cimolodontoides and forms comparable with N. hazeni and
N. hunteri. A single locality, Cochrane 2, provides fossils from four members of
Ptilodus and further close relavtives; Baiotomeus and
Prochetodon This is similar to the kind of diversity
achieved by rodents in some modern communities.
It also means the Alberta faunas can be considerable richer than broadly contemporary
locations further south in the US. Whether this reflects the original situation is unclear,
as other factors could be responsible for biases. For example, the ways rocks were
deposited and local conditons, such as water speeds or soil acidity, can have significant
effects on the prospects for preservation.
Further Mesozoic site summaries can be found at Localities.
Meet (some of) the Mammals
As the location is post-Cretaceous, this listing isn't meant to be complete.
Multituberculata
?Acheronodon sp.;
Anconodon cochranensis;
Baiotomeus rhothonion;
Ectypodus ?szalayi;
Mesodma pygmaea;
Mimetodon silberlingi;
Neoplagiaulax hunteri; N. nelsoni;
Parectypodus corystes; P. sylviae;
Ptilodus gnomus; P. montanus;
Stygimys sp.;
Xyronomys sp.
Eutheria
Gelastops sp.;
Procerberus sp. |
| Genus: Mesodmops Tong Y
& Wang T, 1994 |
| Species: | Mesodmops dawsonae Tong Y & Wang T, 1994 |
| Place: | Wutu Basin, Shandong |
| Country: | China |
| Age: | Lower Eocene |
| Remarks: | Some further information will arrive at some
time. |
| Reference: | Tong & Wang (1994), A new neoplagiaulacid multituberculate
(Mammalia) from the lower Eocene of Wutu Basin, Shandong. Vertebrata PalAsiatica, 32,
p.275-284. (Chinese with summary in English.) |
| Species: | Mesodmops tenuis Missiaen P & Smith T, 2008 |
| Place: | Subeng, Inner Mongolia |
| Country: | China |
| Age: | Upper Paleocene |
| Remarks: | I've got the description on my things to read
pile, so info will follow.
Holotype
The type fossil, IMM-2004-SB-013, is a lower molar kept at the Inner Mongolian Museum.
The specific name comes from the Latin tenuis, meaning thin, slender and that
sort of thing. The molars are comparatively slender in contrast to the other known
species. |
| Reference: | Missiaen & Smith (2008), The Gashatan (late Paleocene)
mammal fauna from Subeng, Inner Mongolia, China, Acta Palaeontologica Polonica, 53(3),
p.358-378. |
| Genus: Mimetodon Jepsen GL,
1940
Aka : Ectypodus (partly); Mesodma (partly); Neoplagiaulax(partly)
Remarks: McKenna & Bell (1997) again lists material from the Upper Paleocene? of
Europe.
| Reassigned species: M. douglassi Jepsen, 1940 see
Baiotomeus douglassi; M. trouesseartianus
Jepsen, 1940 see Parectypodus trouvessartianus | |
| Species: | Mimetodon churchilli Jepsen GL, 1940 |
| Place: | Princeton Quarry, Wyoming |
| Country: | USA |
| Age: | Tiffanian, Middle Paleocene |
| Remarks: | Another Peabody collection holotype. |
| Reference: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Pro. Amer. Philos. Soc, 83, p.217-340. |
| Species: | Mimetodon silberlingi (Simpson GG, 1935) Schiebout,
1974 |
| Aka: | Ectypodus? silberlingi Simpson, 1935; Mesodma silberlingi
Van Valen & Sloan, 1966; ?M. nanophus |
| Place: | Gidley Quarry, Montana & Wyoming & N Dakota & Alberta |
| Country: | USA & Canada |
| Age: | Torrejonian-Tiffanian, Middle Paleocene |
| Remarks: |
The Yale VP catalogue includes E.? silberlingi as well as M. silberlingi.
Weighed about 20g.
Scott, 2003 (p.747), reports on some fossils from a Calgary site called
Who Nose?, which are the earliest traces of this species
in western Canada. These consist of two upper premolars,
three upper molars and three lower premolars, (P4s, M1s and
p4s). As is typically the case for cimolodontan
multis, these p4s are relatively large shearing teeth. In this instance, their crowns
possess 10-11 serrations. They can be admired in the University of Alberta
Multituberculata Sanctuary. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | ?Mimetodon nanophus (Holtzman, 1978) |
| Aka: | Neoplagiaulax nanophus Holtzman, 1978 |
| Place: | Tongue River Formation, North Dakota |
| Country: | USA |
| Age: | Middle-Upper Paleocene |
| Remarks: | Scott, 2005 treats this as a species of
Neoplagiaulax. It's poorly known and, if Scott's
iterpretation is correct, then both the upper and lower fourth
premolars have unusually low crowns with steep front
margins. These characteristics are also applicable for N. serrator (p.xii). This
species may also be present at the Diss locality of ALberta.
Might be the same as M. silberlingi. |
| Reference: | Holtzman (1978), 1978. Late Paleocene mammals of the Tongue
River Formation, western North Dakota. Report of Investigation, North Dakota Geological
Survey, 65, p.1-88. |
| Species: | Mimetodon krausei Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | Another Peabody collection holotype. |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates from
the San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan Basin
paleontology. University of New Mexico Press, Alberquerque. |
| Genus: Neoliotomus Jepsen
GL, 1930
'new Liotomus'
Aka : Eucosmodon (partly)
Remarks: This genus is not within Neoplagiaulacidae. It's considered to be a
ptilodontid-like critter of unclear affinities. |
| Species: | Neoliotomus conventus Jepsen GL, 1930 |
| Place: | Wyoming & Fort Union Formation, Montana & Colorado |
| Country: | USA |
| Age: | Clarkforkian, Paleocene |
| Remarks: | A mighty multituberculate of around 1,9kg. The
holotype is in the Peabody collection. |
| Reference: | Stratigraphy and paleontology of the Paleocene of northeastern
Park County, Wyoming. Proceedings of the American Philosophical Society, 83 (2), p.463-528. |
| Species: | Neoliotomus ultimus (Granger W & Simpson GG, 1928)
|
| Aka: | Eucosmodon ultimus Granger WD & Simpson GG, 1928 |
| Place: | Wyoming & Colorado |
| Country: | USA |
| Age: | Wasatchian, Eocene |
| Remarks: | Slight timekeeping uncertainty
According to the authors, the original material for Eucosmodon ultimus came from the
Wasatch Formation of Wyoming, which overlies the Clark Fork horizon. I've seen this
species referred to somewhere as Clarkforkian, which correlates to late in the Paleocene.
The Wasatchian is mainly lower Eocene, and John Alroy's database gives a timespan of 55 Ma
to 54 Ma for the species. It also indicates that McKenna was the first to reassign the
critter to Neoliotomus in 1960. As the following entry is based mainly on Granger
& Simpson, 1928, I'll be using the older generic name.
Funeral for a Friend
Until 1880 the fossil record of multituberculates was considered to range from the Triassic
to the Jurassic. However, the earlier material was provided by
'haramiyidans', and nobody presently regards then as multis, although there is a view
that at least some may be related. Lemoine then announced the discovery of certain multi
fossils from Paleocene rock in France. These were closely followed by Cretaceous and
Paleocene discoveries from North America. Sadly, that appeared to be the end of this
heroic line. Much mourned by their admirers, these charming animals were consigned to
extinction during the close of the Paleocene. So it goes.
Hello Yellowbrick Road
At least one expert thought the funeral announcement was a bit hasty. This was
Professor Eucosmodon, who claimed to have been actively breeding in an Eocene bed.
Those antics were briefly reported in 1914 but, perhaps distracted by an outbreak of
collective crass insanity in Europe - The War to End All Wars Part One - CNN and the internet
failed to enthuse with the news. Slightly slighted, Professor Eucosmodon went
back to the Eocene bed for some more breeding.
The first of the 'last' multis
One or two liberties have crept into the above text, so I think I'll briefly straighten the
story out. Granger found the first specimen in 1912, and Stein collected three more the
following year. All were obtained from the Sand Coulee beds, and found in association with
typically Eocene placentals. Granger included a brief
mention of their existence in a 1914 paper. As they were found (from G & S, 1928):
"at different localities in different years and by different collectors...", there
was no room left for reasonable scepticism concerning the provenance (p.1).
That pair of authors assigned these remains to the already established genus of
Eucosmodon. (Reminder: McKenna transferred them
in 1960.) If the animals had been alive and kicking, then generic differences might have
been obvious enough. However, none were apparent in 1928 (p.2). Two species were probably
involved, but one of them deigned to deliver nothing more than an
incisor, and thus provided no basis for a specific
definition.
Dental dimensions
The star fossil described was a piece of lower jaw with two teeth; the p4
premolar and the first molar.
This p4 has a length of 11.4 millimetres and is equipped with 14 serrations. Its companion
is 7.3mm long, has a maximum width of 3.7mm and two rows of cusps. Six are on the
buccal side with four on the
lingual.
Two of the other specimens were isolated incisors, and
these broadly conformed to expectations for Eucosmodon. One is both
larger and more compressed than the other, so they probably don't represent the same
species. The second is 6.1mm long, as opposed to 7.3, and closely matches the size then
known from E. americanus. The restricted band of enamel was wider. Which (if either)
belong to E. ultimus couldn't be ascertained.
Holotype
The holotype, AMNH 16103, is a fragment of dentary now
resident in New York. The origin of the specific name isn't revealed, but it's presumably a reference to
the late occurrence of this multi.
Additional notes
Specimens in the AMNH, New York, the Peabody and Wyoming. Known
from a fair number of locations. Another large multi, which weighed perhaps 2 kilos. |
| Reference: | Granger & Simpson (1928), Multituberculates in the
Wasatch Formation, American Museum Novitates, 312, p.1-4. |
| Genus: Neoplagiaulax
Lemoine V, 1882
'new Plagiaulax'
Aka: Ectypodus? (partly); Plagiaulax (partly); Ptilodus (partly)
Remarks: A nomenclatural minefield. Some material has also been reassigned to
Eucosmodon.
2006, New from Montana
According to Bloch J, Boyer D & Krause D (Society of Vertebrate Paleontology Abstracts, 2006,
p.43A9, this genus also occurs at Donald Quarry (Upper Paleocene), Montana. It's
one of at least three multis accused of having lived there during the Tiffanian, by
researchers from the Florida Museum of Natural History and Stony Brook University.
The mammalian fauna reportedly so far includes 30 species. Its named multi mates
are Ptilodus and
Anconodon.
Reference: Lemoine (1882), Sur deux Plagiaulax tertiaires, recueillis aux environs de Reims.
Comptes Rendus de l'Academie des Sciences, Paris, 95, p.1009-1011.
| Reassigned species: N. americanus Cope, 1885 see
Eucosmodon americanus and
Eucosmodon primus; N. douglassi
Schiebout, 1974 see Baiotomeus douglassi;
N. fractus Dorr, 1952 see Ptilodus fractus;
N. molestus Cope, 1886 see Eucosmodon
molestus; N. nanophus Holtzman, 1978 see
?Mimetodon nanophus; N. trouessarti see
Parectypodus trovessartianus | |
| Species: | Neoplagiaulax eocaenus (Lemoine V, 1880) Lemoine,
1882 |
| Aka: | N. eocänus, Plagiaulax eocaenus |
| Place: | Cernay |
| Country: | France |
| Age: | Upper Paleocene |
| Remarks: | According to Scott, 2005 (p.xi not the orginal
page number), both the upper and lower fourth premolars
display an unusually wide range of variation. This suggests the possibility that a larger
number of taxa may be bundled together with this species.
Euro Neoplagiaulax
None of the North American cousins seem to show signs of particularly close affinities with
the European branch of the genus (p.xxviii). The American N. serrator,
N. paskapooensis, N. hazeni and N. hazeni all have similarities in the
p4 lower premolar with the Europeans N. eocanus and N. copei. However, they're
generally more like their North American colleagues. The similarities seem to be matters
of convergence. Whether the taxon is a genuine genus is also in doubt. It could be a
looser association of neoplagiaulacids belonging to more than one, rather similar generic
lineage.
Additional notes
Descendant of N. hazeni, (Burkitt JH), but this seems unlikely. A specimen is in the
Peabody, Yale. |
| References: | Lemoine (1880), Communication sur les Ossements fossiles des
terrains tertiaires inférieurs. Association Française pour l'Avancement des Sciences,
Reims, p. 3-40. |
| Lemoine (1882), Sur deux Plagiaulax tertiaires, recueillis aux
environs de Reims. Comptes Rendus de l'Academie des Sciences, Paris, 95, 1009-1011. |
| Species: | Neoplagiaulax copei Lemoine V, 1885 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | Descendant of N. hazeni, (Burkitt JH).
Specimens at the AMNH, New York. |
| Reference: | Lemoine (1885), Étude sur quelqes mammifères de petite taille de
la faune cernaysienne des environs de Reims. Bull. Soc. Géol. France 3, p.203-217, pls.
x-xii. |
| Species: | Neoplagiaulax grangeri (Simpson GG, 1935) Gazin,
1969 |
| Aka: | Ectypodus? grangeri Simpson, 1935d |
| Place: | Gidley Quarry, Montana |
| Country: | USA |
| Age: | Torrejonian, Paleocene |
| Remarks: | Descendant of N. hazeni, (Burkitt JH).
Weight of around a quarter of a standard rat, 100g. |
| Reference: | Simpson (1935), New Paleocene mammals from the Fort Union of
Montana. Proc. US Nation. Museum 83, p.221-244. |
| Species: | Neoplagiaulax hazeni (Jepsen GL, 1940) Krause DW,
1977 |
| Aka: | Ectypodus hazeni Jepsen GL, 1940; N. fractus
(partially) |
| Place: | Princeton Quarry, Wyoming & North Dakota |
| Country: | USA |
| Age: | Tiffanian, Middle-Upper Paleocene |
| Remarks: | Further material, including the type fossil, can
be visited at Yale. Body weight estimated at 95g. |
| References: | Jepsen (1940), Paleocene faunas of the Polecat Bench formation,
Park County, Wyoming. Proceedings of the American Philosophical Society, 83 (2), p.217-338. |
| Krause (1977), Paleocene multituberculates (Mammalia) of the Roche
Percee Local Fauna, Ravenscrag Formation, Saskatchewan, Canada. Palaeontographica Abteilung
A 159, p.1-36. |
| Species: | Neoplagiaulax hunteri (Simpson GG, 1936) Krause DW,
1977 |
| Aka: | Ectypodus hunteri Simpson, 1936c |
| Place: | Alberta and Scarritt Quarry, Montana & Wyoming & North
Dakota |
| Country: | Canada & USA |
| Age: | Torrejonian-Tiffanian, Middle Paleocene |
| Remarks: | Several specimens are at the Peabody, Yale, where
the name E. is sometimes employed. Weighed about 45g.
Several specimens have recently been identified from the
Who Nose? fauna of Calgary, Alberta, (Scott 2003, p.750). |
| References: | Simpson (1936), Census of Paleocene mammals. American Museum Novitates
848, p.1-15. |
| Krause (1977), Paleocene multituberculates (Mammalia) of the Roche
Percee Local Fauna, Ravenscrag Formation, Saskatchewan, Canada. Palaeontographica Abteilung
A 159, p.1-36. |
| Species: | Neoplagiaulax macintyrei Sloan RE, 1981 |
| Place: | San Juan Basin, New Mexico & Utah |
| Country: | USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | |
| Reference: | Sloan (1981), Systematics of Paleocene multituberculates from the
San Juan Basin, New Mexico, p. 127-160, in Lucas et al (eds), Advances in San Juan Basin
paleontology. University of New Mexico Press, Alberquerque. |
| Species: | ?Neoplagiaulax burgessi Archibald JD, 1982 |
| Place: | Hell Creek, Montana |
| Country: | USA |
| Age: | Maastrichtian, Upper Cretaceous |
| Remarks: | This species is an early representatvie. |
| Reference: | Archibald (1982), A study of Mammalia and Geology across the
Cretaceous-Tertiary Boundary in Garfield County, Montana. University of California
Publications in Geological Sciences, volume 122, p.242-243. |
| Multituberculate Hunting and Fossil Biases
The following is derived from my reading of Fox, 1968, (see Bibliography).
Fox's paper concerns the diversity of the then known
multituberculate genera in North America during the Upper Cretaceous - Paleocene. Much
more material has since been discovered, but his observations still offer relevant insights
regarding limitations of the known fossil record, at whatever stage of research. It was
written in response to a view that generic diversity of multis increased during the
Campanian and Maastrichtian. Fox found this uncertain, (p.339).
First find your fossils
There are two standard methods of prospecting for small fossils. One involves crawling
around on your hands and knees, and staring at the ground. I've done this when looking for
remains of belemnites. It works but it's a great way of confusing the eyes, deadening the
fingertips and numbing the mind. You also don't recover anything from just below the
surface. The second method involves processing rock or sand through sieves and screens.
This sorts the material by size, which makes the recognition of fossil remains easier.
Screening also increases the scope of the sample. This isn't a replacement for crawling
around. That may help decide where to sieve.
Screening techniques have substantially increased both the number and variety of mammal
remains available. However, they can only help reveal what's there to be found. Inherent
biases of the fossil record still remain unaffected, and require consideration.
RIP
The relevant sites are generally death assemblages. Remains were brought together post
mortem by some mechanism or other; often river action. Consequently, it can't be reasonably
assumed that the fossils are necessarily a typical representation of the paleo-fauna. In
life there might have been more diversity. Processes of fossilization may have favoured
preservation of particular faunal sections. Human choice and chance are involved in exactly
which locations are sampled, and inferences are made on account of the available evidence.
All these factors can introduce biases.
This means that conclusions concerning an increase in the proportionate number of
multituberculates within the total mammalian fauna could be less secure than they may
appear, (p.340): "... the "total mammal fauna" of this interval has never
been known, is not known, and never shall be known." (This refers specifically to the
Lance and Bug Creek strata, but it equally applies to other localities.)
Insufficient sampling could also be a source of bias. If a location continues to yield new
taxa, then it would be premature to assume, that the broad
picture is sufficiently known. Plenty of new taxa have been described since this paper was
published, (1968), and there's nothing to indicate that the supply is running dry. This is
in part, but not only, due to new localities.
The plains
Generally, the Upper Cretaceous strata in North America which yield multis are ancient
floodplains, which then bordered the mid-continental sea. This environment would have been
divided into smaller habitat zones, as dictated by the presence of rivers, streams, lakes
and swamps (p.341), (and presumably further factors). Higher lands existed further to the
west, and conditions must've differed to those of the floodplains. This suggests the
inhabitants also differed. As upland conditions weren't favourable for fossilization, that
fauna is largely unknowable. Concerning dinosaurs, the relative paucity of juvenile remains
in many locations cannot reflect a genuine shortage of young dinos. (That's how all the
adults started out.) It must indicate a bias, which may well be the result of different
habitats at differing stages of life. "There is no a priori reason why mammals of
diverse kinds could not have been similarly distributed."
Missing multis
Fox refers to four multituberculate genera which then were, and still are, unknown from
deposits earlier than the Lower Paleocene: Eucosmodon, Ptilodus,
Neoplagiaulax and Parectypodus. "Only the paleontologically deficient
would suppose that those sprang fresh from the brow of Jove at the time of the demise of
the dinosaurs." Each of these genera was probably established somewhat earlier than
the age of the oldest finds, and the Upper Cretaceous isn't unlikely. In all cases,
there's a chance that they first arose in the blank spaces of the fossil record, (which are
most of it). Whilst there may have been an increase in North American multi diversification
during the Upper Cretaceous, this could also be an artefact resulting from biases of
preservation and sampling. |
| Species: | Neoplagiaulax kremnus Johnston PA & Fox RC,
1984 |
| Place: | Rav W-1, Saskatchewan & Montana |
| Country: | Canada & USA |
| Age: | Puercan, Lower Paleocene |
| Remarks: | Holotype at Alberta. |
| Reference: | Johnston & Fox (1984), Paleocene and Late Cretaceous mammals
from Saskatchewan, Canada. Paleontogr. Abt. A: Paläozool., Stratigr. 186, p.163-222.
|
| Species: | Neoplagiaulax annae Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Neoplagiaulax nicolai Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Neoplagiaulax sylvani Vianey-Liaud M, 1986 |
| Place: | Cernay |
| Country: | France |
| Age: | Paleocene |
| Remarks: | |
| Reference: | Vianey-Liaud (1986), Les Multituberculés Thanétiens de France,
et leurs rapports avec les Multituberculés Nord-Américains. Palaeontogr. Abt. A: Paläozool.
Stratigr. 191 p.85-171, 3 plates. |
| Species: | Neoplagiaulax jepi Sloan RE, 1987 |
| Place: | Cedar Point Quarry and
The Breaks, Wyoming |
| Country: | USA |
| Age: | Tiffanian, Paleocene |
| Remarks: | |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammal ages,
biozones, magnetozones, rates of sedimentation, and evolution, in Fassett JE &
Rigby JK (eds.), The Cretaceous-Tertiary boundary in the San Juan and Raton Basins, New
Mexico and Colorado, Geological Society of America Special Paper 209, p.165-200. |
| Species: | Neoplagiaulax macrotomeus (Wilson, 1956) Sloan,
1987 |
| Aka: | Ectypodus macrotomeus Wilson, 1956 |
| Place: | San Juan Basin, New Mexico |
| Country: | USA |
| Age: | Puercan-Torrejonian, Lower Paleocene |
| Remarks: | Derived from Mesodma formosa, (Burkitt
JH). Weighed in at about 15g. |
| Reference: | |
| Species: | Neoplagiaulax mckennai Sloan RE, 1987 |
| Aka: | N. mckennaiai |
| Place: | Love Quarry, Wyoming & North Dakota |
| Country: | USA |
| Age: | Tiffanian, Middle-Upper Paleocene |
| Remarks: | Weight guestimate, 60g. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammal ages,
biozones, magnetozones, rates of sedimentation, and evolution, in Fassett JE &
Rigby JK (eds.), The Cretaceous-Tertiary boundary in the San Juan and Raton Basins, New
Mexico and Colorado, Geological Society of America Special Paper 209, p.165-200. |
| Species: | Neoplagiaulax nelsoni Sloan RE, 1987 |
| Place: | Wyoming & Purgatory Hill, Montana & Alberta |
| Country: | USA & Canada |
| Age: | Puercan- lower Tiffanian, Paleocene |
| Remarks: |
The type fossil is from Keefer Hill, (aka Shotgun), Wyoming. At
least one specimen is at Yale. A mouse-sized 25g.
An upper premolar (P4) has recently been identified in the
Who Nose? fauna of Alberta, (Scott 2003, p.750). If
correctly diagnosed, this shows that N. nelsoni and N. hunteri coexisted. It
has previously been suggested that this species was ancestral to the second named one,
partly because it was geologically older. |
| Reference: | Sloan (1987), Paleocene and latest Cretaceous mammals, rates
of sedimentation and evolution, p.165-200 In Fassett JE & Rigby JK (eds.), The
Cretaceous-Tertiary Boundary in the San Juan and Raton Basins, New Mexico and Colorado.
Geological Society of America Special Paper, 209. |
| Species: | Neoplagiaulax serrator Scott CS, 2005 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
Remains or this species are relatively extensive for a neoplagi. Finding upper and lower
jaws in association is unusual for these critters, yet the Paskapoo Formation managed to
provide such a specimen. It was a middling-sized member of the genus. In terms of lower
premolar length (p4), N. serrator is 25% larger
than N. macintyrei and N. nanophus (see Mimetodon
nanophus), but 25% smaller than N. mckennai and N. grangeri (p.vii).
This tooth has more serrations than for any other species. It appears to be most similar
to N. hunteri, N. kremnus and N. eocaenus. However, both lower p4 and
upper P4 have lower crowns, and are nevertheless steeper at the front. A further contrast
to the last mentioned species is the retained p3.
Upper premolars
The first upper approaches an oval shape when viewed from the
occlusal perspective, and has two cusps on the labial
side and a singleton to the rear on the lingual portion.
P2 is double-rooted and roughly circular (p. viii). A large, labial cusp dominates and
two smaller ones are to the lingual. P3 has a lower crown. It's also got two roots but
the outline of the crown is more rectangular. A pair of cusps is found on both sides.
Upper multi P4s were more complex teeth, as they were involved in cutting food rather than
simply keeping hold of the stuff. Cusp numbers are variable. Up to two are on the labial
side (usually one but sometimes none), ten are generally arrayed along the middle (counts of
nine and eleven also occur), and the lingual portion of the crown is a cusp-free zone. The
tooth is wider at the front than the rear, and also low in height. The cusps of the middle
row increase in size along the series until the final two or three. These premolars are
most similar to counterparts from N. hunteri but they're shorter, narrower and
lower.
Upper molars
The molars also have most similarity with N. hunteri, but they're shorter and the
M1s don't have as many cusps. The most popular form is 7:12:6 (
buccal to lingual). The lingual row is the most
variable in number (5-8), and commences alongside the third to sixth cusp of the middle row.
The M2 is a smaller tooth with only two cusp rows (3-4:4).
Lower jaw
The dentary doesn't differ much from other Neoplagiaulax
species or known ptilodontoids for that matter. The main branches of the bone are deep, and
this applies particularly for the area beneath the
postcanines (p. ix). There's a strong coronoid process beginning internally from
alongside of the first lower molar. The top of this process is damaged, but it reached a
height superior to that of the p4 crown. The dentary condyle (the lower part of the jaw-skull
joint) is large and wide. Each specimen has at least two mental foramina beneath the
tooth row.
Lower incisor
As typical for multis there was only one per jaw half. This was a long, elegant tooth
flattened on the internal side.
Lower premolars
Also typical of cimolodontan multis is the pathetic p3.
Some more derived neoplagis were so unimpressed with this
inheritance, that they dispensed with the tooth entirely.
The p4 was the only real chopping tooth on the dentary, and its crown is relatively long and
low judged against Neoplagiaulax norms. The front of the blade rises steeply and is
mildly convex while the rear slope descends more gently. Plentiful serrations occur along
the way. There are between sixteen to nineteen of them, with seventeen being the most
popular number. The foremost ones are rather fine, but the serrations become larger along
the line. The blade reaches its highest point between the sixth and tenth serrations, and
this seems to be characteristic for the genus.
Both sides of the blade are flat excepting for ridges associated with the serrations, although
not in the case of the final three or four. Often, there's a large, round wear facet
towards the rear on the labial face (p. x).
Lower molars
Most commonly, the m1 has a cusp formula of 10:5 (buccal-lingual),
though only four cusps for the internal row also occurs. Crowns are close to rectangular
in outline, and the rows drift further apart from one another towards the rear. For the
buccal row, the cusps vary from being near to pyramids (front) to crescents (rear). They
also become increasingly tall to the fifth or sixth, and then remain about the same height.
An exception can occur in the form of a larger final cusp.
The lingual cusps have flat 'internal' faces and convex
lingual ones. I suppose 'internal' here refers to buccal and the perspective is from the
centre of the crown. The foremost cusp is a bit of a dwarf but the rest are both bigger
and higher. The final member is the biggest, and can be up to twice the length of its front
neighbour. These m1s aren't much different from those of N. hunteri. However,
they're smaller and typically possess one fewer lingual cusp. The buccal faces for both rows
of cusps carry strong grooves caused by wear. The lingual surfaces of some lingual cusps
have weaker grooving.
The cusp formula of the m2 is more variable. This could perhaps partly be due to the larger
number of specimens, as the second molar wins by 22-15. Most popular is 5:2 but the range
is 4-6:2-3. The crown is approaching a trapezoid in outline. Buccal cusps are crescent-shaped
while the lingual ones are larger. Of those, the first is a crescent with the second being
more like a pyramid. In contrast to the m1, the grooving effects are strongest on the
lingual faces. This difference is caused by the relative positions of the molars, as they
weren't aligned straightly.
Affinities
N. serrator appears most closely related with N. hunteri and N. kremnus.
However, the lowness of the crowns of the fourth premolars, both upper and lower, and the
low placement of the first serration (p4) seem to be comparatively primitive traits (p.xii).
The large number of serrations is a peculiarity of the species.
Holotype
The type fossil, UAL VP 46025, is a partial skull with lower
mandible in the collection of the University of Alberta, Edmonton. The specific name
is Latin for 'sawyer', and this refers to the plentitude of serrations on the lower p4
rather than any Twain-esque literary ambitions. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Species: | Neoplagiaulax paskapooensis Scott CS, 2005 |
| Aka: | N. hunteri (partly) |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
This is a relatively large species (p.xii). In terms of the length of the p4
premolar, it beats N. macintyrei and N.
nanophus (see Mimetodon nanophus) by 35%. Nevertheless,
it's around 10% shorter than N. mckennai and N. grangeri. This tooth is also
relatively long in comparison to its height, which also means the crown's low. A contrast
to N. serrator is the gentler slope of the front margin. The closest similarities
are with N. hunteri and N. copei.
Exceptionally for a neoplagi, the upper dental series of the holotype is complete, and only
the left m2 is absent from the lower jaws. Such a complete set hadn't previously been
reported.
Upper incisors
There are two per side, I2 and I3. The ancestors got rid of I1 earlier. I2 is a long
tooth, but the crown only accounts for a third of it (p.xiii). The root is elliptical in
cross-section, and this is consistent with permanent rather than
deciduous incisors. Both I2s run roughly parallel with each other. They're not closely
packed together as known from microcosmodontids
and djadochtatherioids. The I3 is a broader, shorter and chunkier
incisor (p.xiv). A lack of discernable wear facets suggests this tooth didn't directly
occlude with the lower one.
Upper premolars
The expected number would be four per side and that's how many are present. Apart from
being a bit larger, the first three are much like the corresponding teeth of N. serrator
and N. hunteri. P2 deviates to some extent, as the
lingual cusp row is composed of a duo rather instead of a soloist.
P4 most closely resembles N. hazeni, but it's both lower crowned and smaller. The
most common cusp formula is given as (0)4:8:0 (labial to
lingual). Seen from the side, the tooth has a fairly straight front slope with a steeper,
somewhat concave descent to the rear. A cusp is sometimes present low down at the back of
the crown, while a labial lobe is always found at the front, and it houses from two to four
cusps.
Upper molars
The most common cusp formula for the first molar is 7:10:4 but variation on that occurs in
all rows. The buccal cusps are similar to one another in
height with the exception of the smaller first one. The middle row cusps are larger. Most
are quadrate in outline, but there's a tendency towards a slightly crescent shape further
back along the line. The lingual row is shorter, as it ends next to the fifth of sixth
middle cusp. Strong grooving isn't apparent on the faces of the middle cusps, and this is
in contrast to the situation found with N. hazeni (p.xv).
Second molars have two cusp rows; 3:3. Rather than a buccal row, the cusps have been
amalgamated into a long ridge. The middle row commences with a small, low cusp which is
followed by two larger companions. Lingual cusps are
smaller and lower than the middle ones, and they diminish along the line from front to
back. The only discernable wear consists of light grooves on the lingual faces of the
lingual cusps.
Lower jaw
What's known of the dentary is in broadly in line with other
neoplagis, but there are some differences of detail. For example, the dentary condyle is
set at a lower level than for N. serrator, and the area for articulation with the
skull joint is more elongated and has a greater area.
Lower incisor
As was the multi wont there was only one per side. It's a stronger and longer tooth than
found in N. serrator; closer to N. hazeni. The incisor lies procumbently
and curves in towards the middle to some degree. Wear on the upper surface was mostly
caused by the I2.
Lower premolars
The p3 is a small piece of junk, which tried to hide its inadequate physique by taking
refuge in a concavity on the front of the only functional premolar.
The p4 is largely a blade with (usually) 14 serrations. In some cases there's one less
(p.xvi). From the occlusal perspective, the outline of
the crown approaches a trapezoid in shape. At the front, the blade ascends more gently
than is the case for N. serrator. The first serration is located higher up than is
usual for the genus, at a position about one sixth along the length of the tooth. The crown
climaxes in height at the fourth or fifth serration, and then descends. Serrations on the
downwards journey are closer to each other and rougher. The sides of the blade are adorned
with ridges which begin at the serrations, excepting for the final three or four.
Lower molars
The most fashionable cusp formula for the m1 (buccal to
lingual) us 7:4, but there's sometimes a fifth cusp for the
internal row. The outline of the tooth is roughly rectangular, and there's only a narrow
valley between the cusp rows. Buccal cusps are robust. Those to the front are four sided
whereas the rear two or three are somewhat crescentric. There's an increase in dimensions from
the first to the fourth or fifth, with the rest being similarly sized. Lingual cusps are
also robust but higher. With the exception of the smaller leading one, these cusps are
close to one another in size. Wear has left a measure of grooving on the buccal faces.
This molar is reminiscent of N. hazeni but it's smaller, has less cusps and the
buccal ones are less crescent-shaped.
The m2 cusp formula is 4:2. Buccal cusps don't differ much in size and are somewhat more
crescentric than their m1 counterparts. Lingual cusps are bigger, and grooving is sometimes
evident on the lingual face. The first is crescent-shaped while its follower is more
triangular. Given the similarities evident from other teeth, this is unsurprisingly also
most like the corresponding tooth of N. hazeni.
Neoplagi puzzles
N. paskapooensis resembles N. hazeni, but some distinctions are mentioned
above. The lower p4 also has features in common with N. copei from France.
However, the average length is less (4.85mm against 5.51), the crown is proportionately
lower and there are less serrations (p.xvii).
In the case of the holotype, the dentition was found as an
almost complete set. Had they been isolated, then there's a strong chance some may well
have been referred to N. hazeni. This serves to emphasize the diagnostic importance
of the lower p4 premolar, as that's where significant distinctions are at their most
concentrated and helpful (p.xviii).
Holotype
The type fossil, UAL VP 46138, is a partial skull with remains of associated lower jaws.
The specific name refers to the Paskapoo Formation, and the word is Cree for 'blind man'.
Some of the material had previously been assigned to N. hunteri. |
| Reference: | Scott (2005), New neoplagiaulacid multituberculates (Mammalia,
Allotheria) from the Paleocene of Alberta, Canada, Journal of Paleontology, 79(6),
p.1189-1213. |
| Species: | Neoplagiaulax cimolodontoides Scott CS, 2005 |
| Place: | Paskapoo Formation, Alberta |
| Country: | Canada |
| Age: | Tiffanian, Paleocene |
| Remarks: | The following is based upon my reading of the
text from Scott, 2005. Any page numbers mentioned are in Roman numerals, and these don't
correspond at all with those in the original publication. If anybody feels moved to send
a full copy of the original, it would be most welcome.
This is a somewhat eccentric species, and it shares this characteristic with vertebrate
paleontologists. The lower p4 premolar has a higher, more
arched crown than other members of the genus (p.xviii), and there are other dental details
as well. Some of those are similarities reminiscent of a North American multi called
Cimolodon, which isn't a member of the neoplagi family.
These are matters of convergence. It's particularly unusual for more welcome reasons.
Exceptionally for neoplagis, it saw fit to supply reasonably generous portions of its skull.
The animal also donated information on patterns of tooth replacement.
Skull
Most information on ptilodontoid heads had been provided by specimens of
Ptilodus montanus and fragments from
Prochetodon cavus, Ectypodus tardus and
Krauseia. Three fossils of N. cimolodontoides
(including the holotype) have added much to the knowledge of neoplagi ptilodontoids;
specifically the maxilla, part of the
zygomatic arch of the cheek region and the secondary
bony palate. Crushing and fracturing blur some details but beggars and lovers of ancient
mammals can't always be choosers.
A process of the maxilla helps build the front of the zygomatic arch (aka cheek bone), and
this begins close to the final premolar. Unfortunately, this process is the only part of
the arch available. Another piece of the maxilla is termed the palatal process, and this
commences just behind the first premolar (p.xix), and
continues until in front of the alveolus for the second
molar. This palate is relatively broad, and there's a naturally
occurring hole in it between the P3 and 4; a so called vacuity. Such vacuities are popular
with various mammals, but evidence for them in neoplagis hadn't previously been available.
It's similar to what's known from Ptilodus montanus, while being shorter and broader
than in a specimen of Ectypodus tardus. Another feature is an odd pocket in the bone
at the front of the palatal process. Something of the like also occurs in Ptilodus,
but quite what this housed is unclear. One possibility is some form of gland.
Upper premolars
The front three of the four premolars resemble those described for both N. hunteri
and N. serrator, but there are some contrasts (p.xx). For one thing, these ones are
a bit bigger. More importantly, the enamel contains ridges with vertical grooves between
them, with the grooves strongest near to cusps. This effect is also present for a number
of cimolodontid and ptilodontid
multis.
The P1 has a triangular arrangement of a front cusp and two rear ones. The pair on the
labial side are triangular in cross section, whereas the single,
lingual one is more like a cone. The crown's supported by
two thick roots. P2 is fairly similar in most regards, but P3 is a bit bigger and has a
more quadratic outline. This crown is also set a touch lower than the others. It's got two
rows of cusps. In all cases, these teeth are relatively long, and an elongation at the rear
on the lingual side is packed closely with the front of the following tooth.
The most common cusp formula for the P4 is given as (0)0:8:0 (labial to lingual), but
another cusp is sometimes |
