A new species of ghost knifefish has been described from the Amazon River.
The decription of the new species, Adontosternarchus nebulosus, by John Lundberg and Cristina Fernandes has been published in the latest issue of the journal Proceedings of the Academy of Natural Sciences of Philadelphia.
The new species has been given the common name of Clouded ghost knifefish (the specific name nebulosus means clouded in Latin, and refers to the bold colour pattern of dark irregular blotches) by the authors, and is commonly found throughout the main channel of the Amazon River and its black- and whitewater tributaries.
Adontosternarchus nebulosus can be distinguished from other members of the genus in having a boldly contrasting colour pattern of irregular, dark blotches on the back and sides followed posteriorly by a long pallid area extending far onto the caudal peduncle, relatively few anal-fin rays (112-154), relatively few vertebrae counted to base of last anal-fin ray (52-57), a relatively deep body: 21-33% of distance to origin of dorsal filament, and body depth below the origin of the dorsal filament less than or equal to the postorbital distance.
The new species was caught from depths of 2"30 m, and is a generalized feeder on benthic invertebrates: gut-content analysis revealed small cladocerans, nematode worms, protozoans and rotiferans.
There are four other species of the genus Adontosternarchus: A. balaenops and A. clarkae from the Amazon River drainage, A. sachsi from both the Amazon and Orinoco river drainages, and A. devenanzii from the Orinoco River drainage.
For more information, see the paper: Lundberg, JG and CC Fernandes (2007) A new species of South American ghost knifefish (Apteronotidae: Adontosternarchus) from the Amazon Basin. Proceedings of the Academy of Natural Sciences of Philadelphia 156, 27"37.