Before 2003, three species were recognized from this genus (S. formosus, S. jardinii, and S. leichardti). In that year, a study was published which determined several naturally-occurring color varieties of S. formosus, the Asian arowana, actually comprised four separate species, bringing the species count for the genus to six.
The ancestor of the Australian arowanas, S. jardinii and S. leichardti, diverged from the ancestor of the Asian arowanas about 140 million years ago, during the Early Cretaceous period. The morphological similarity of all six species shows that little evolutionary change has taken place recently for these ancient fish.
Scleropages Inscriptus, a New Fish Species from the Tananthayi or Tenasserim River Basin, Malay Peninsula of Myanmar (Osteoglossidae: Osteoglossiformes)
Apr 15, 2012; INTRODUCTION About ten years ago word reached Bangkok that scleropages occurs in the Myanmar part of the Malay Peninsula....
Clarification of the Occipito-Vertebral Region of Arapaima gigas (Osteoglossomorpha: Osteoglossidae) through Developmental Osteology
Feb 28, 2007; The structure and composition of the ventral portion of the occipital region of the skull in Arapaima gigas (Osteoglossidae) is...