Tuesday, February 13, 2018

[Ichthyology • 2018] Melanosternarchus amaru • A New Genus and Species of Electric Ghost Knifefish (Gymnotiformes: Apteronotidae) from the Amazon Basin

Melanosternarchus amaru 
Bernt, Crampton, Orfinger & Albert, 2018

We describe Melanosternarchus amaru as a new genus and species of Apteronotidae from the deep channels of blackwater and clearwater tributaries of the Amazon River in Brazil and Peru. The new species superficially resembles members of the widespread “Apteronotusbonapartii species group, from which it can be readily distinguished by expanded bones of the infraorbital laterosensory canal. It can further be distinguished from all other apteronotids by a unique combination of characters: reduced premaxillary dentition, a large gape, and an absence of scales from the entire dorsum. A molecular phylogenetic analysis using three mitochondrial loci and one nuclear locus (~3000 bp) places this genus as sister to Compsaraia, and these two genera together as a clade sister to Pariosternarchus; all nodes with strong statistical support. The clade formed by these three genera includes five species, four of which are restricted to the Amazon basin. The apparent habitat preference of the new species for low-conductivity blackwater and clearwater rivers has not been reported in other apteronotid species.

Keywords: Pisces, Neotropics, Peru, Brazil, diversity, Blackwater, taxonomy

FIGURE 2. Lateral view of two living specimens of Melanosternarchus amaru, ANSP 200459.

Melanosternarchus, new genus

Type species. Melanosternarchus amaru, new species,
by monotypy and original designation.

Etymology. Melano from the Greek melas, meaning black in reference to dark pigmentation and presence in blackwater rivers, and sternarchus, a name commonly used in apteronotid taxonomy, from the Greek sternon (chest) and archos (rectum), referring to the anterior position of the anus.

Melanosternarchus amaru, new species

Etymology. The species name is from the Quechuan amaru, a mythical serpent, referring to the snakelike shape of this fish. A noun in apposition.

Maxwell J. Bernt, William G. R. Crampton, Alexander B. Orfinger and James S. Albert. 2018. Melanosternarchus amaru, A New Genus and Species of Electric Ghost Knifefish (Gymnotiformes: Apteronotidae) from the Amazon Basin. Zootaxa. 4378(4); 451–479. DOI: 10.11646/zootaxa.4378.4.1

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