Pachystomias Günther, 1887

Villarins, Bárbara T., Dario, Fabio Di, Eduardo, Leandro N., Lucena-Frédou, Flávia, Bertrand, Arnaud, Prokofiev, Artem M. & Mincarone, Michael M., 2022, Deep-sea dragonfishes (Teleostei: Stomiiformes) collected from off northeastern Brazil, with a review of the species reported from the Brazilian Exclusive Economic Zone, Neotropical Ichthyology (e 220004) 20 (2), pp. 1-78 : 43

Pachystomias Günther, 1887

Diagnosis. Pachystomias can be distinguished in the Malacosteinae by the very large and crescent-shaped suborbital organ, red or orange in fresh specimens; body depth about 13.8-20.0% SL; two nostrils on either side of head; a small postorbital organ below eye; mouth floor, i.e., the membrane between the mandibular symphysis and the hyoid, present; chin barbel without terminal bulb, its length shorter than head length in adults but about equal to 50% SL in juveniles; teeth uniserial in jaws, curved; 5–6 pectoral-fin rays, reduced in length; dorsal- and anal-fin bases approximately equal in length, anal-fin origin just posterior to dorsal-fin origin; photophores in both ventral and lateral series with long spaces separating them into clearly distinct groups (Morrow, Gibbs, 1964; Gibbs, 1986c; McEachran, Fechhelm, 1998; Kenaley, Stewart, 2015g; Sutton et al., 2020). A single valid species (Fricke et al., 2022).