Megalosciades gen. nov.

(Figs 1–3, 45)

ZooBank registration: urn:lsid:zoobank.org:act: 1DF58A15- AE63-4686-BEE0-9511F9971FFF.

Type species: Arius augustus Roberts, 1978 .

Diagnosis

The genus Megalosciades is defined based on unique characters of external morphology reported by Roberts (1978) in the species description: extremely short maxillary barbel; very small eye; broad head and broad mouth.

Etymology

Named for the disproportionally large head of the type species in comparison to those observed in Sciades and close relatives. Gender: masculine.

Included species

Megalosciades augustus Roberts, 1978 .

Habitat and distribution: Freshwater, southern New Guinea (Fig. 38).

Remarks

Over that past two decades, Megalosciades augustus has been treated by different authors as a valid species in three different genera: Arius, Nemapteryx, and Neoarius . Molecular data (Betancur-R. 2009) does not support the inclusion of that species within any of those genera, nor does it appear to be the sister group of any of them. Although BI and ML analyses support the inclusion of Megalosciades augustus in Cochlefelis, the two genera are externally very distinct (Figs 45, 53) and the absence of internal morphological data makes it impossible to establish a diagnosis. This is an unstable situation, which may be resolved by assigning that enigmatic species to its own genus, within which it can remain until a discoverery that its phylogenetic position is actually embedded within another genus.