The serrulate whiptail has the usual greatly elongated pointed tail of the rattails, as well as large eyes and a raised profile peaking at the start of the dorsal fin. It has a markedly serrate first dorsal fin ray of its congeners and lacks the photophore possessed by all other Caelorinchus species. There are three spiked processes on the front of the snout, termed sclerites; enlarged, modified scales that like the chin barbel of these fishes may be used as sensory organs.

Color is uniformly dark grey, with a patch of blue-black on the abdomen, a silvery eye, and all fins except the second dorsal are black.

References

• Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand, (William Collins Publishers Ltd, Auckland, New Zealand 1982) ISBN 0-00-216987-8