Cephalocassis Bleeker, 1852

Marceniuk, Alexandre Pires, Oliveira, Claudio & Ferraris Jr, Carl J., 2024, A new classification of the family Ariidae (Osteichthyes: Ostariophysi: Siluriformes) based on combined analyses of morphological and molecular data, Zoological Journal of the Linnean Society 200 (2), pp. 426-476 : 455-456

Cephalocassis Bleeker, 1852

( Figs 1–3 , 24B , 28 )

Type species: Arius melanochir Bleeker, 1852 .

Diagnosis

Posterior branches of mesethmoid narrow (6, 0> 1); posterior branches of mesethmoid parallel throughout their entire extension (7, 0> 1); anterior portion of anterior cranial fontanel not delimitedbydorsalexpansionoforbitosphenoid (24, 1> 0); fenestra delimited by parieto-supraoccipital, pterotic and sphenotic present (34, 0> 1); parieto-supraoccipital process base almost as narrow as posterior portion (46, 1> 0); vomer anterior margin very pronounced and acute (50, 0> 1); tooth plates associated with vomer absent (55, 1> 0); lateral expansions of orbitosphenoid and pterosphenoid absent (64, 1> 0); optic foramen very reduced (67, 1> 2); basioccipital lateral process absent (82, 1> 0); space between transcapular process and otic capsule very small (89, 1> 2); teeth on dentary restricted to mesial two-thirds (116, 1> 0); premaxilla narrow and very long, its length two to three times in width (120, 1> 2); interopercle anterior portion conspicuously narrow (133, 0> 1); metapterygoid one and one-half times longer than deep in perpendicular section (135, 1> 2); ventral crest of hyomandibula absent (142, 0> 1); second external branchiostegal ray almost as wide as first ray (148, 0> 1); second basibranchial spindle shaped (166, 1> 0); first hypobranchial very elongate transversely, with well-developed and acute mesial face (172, 0> 1); anterior process of first hypobranchial very conspicuous (173, 0> 1); second hypobranchial very elongate transversely, its mesial face acute (176, 0> 1); posterior margin of fourth epibranchial slightly convex, one-fourth as wide as long (187, 0> 1); accessory crest connecting transverse and median crests associated with neural spine of fourth vertebra present (204, 0> 1).

Ambiguous optimization: Posterior cranial fontanel very wide and long (27, 2> 3).

Included species

Cephalocassis melanochir Bleeker, 1852 .

Habitat and distribution: Freshwater, Southeast Asia ( Fig. 24 ).

Remarks

Hemipimelodus had been treated as a junior synonym of Cephalocassis in recent morphological studies ( Marceniuk and Menezes 2007, Marceniuk et al. 2012), a condition supported by an extensive list of shared synapomorphies (2, 15, 50, 85, 116, 120, 135, 142, 166, 204, 148, 200, and 222) including an autapomorphy (presence of a fenestra delimited by the supraoccipital, pterotic, and sphenotic). The total-evidence analysis, however, corroborates results of a previous molecular analysis (Betancur-R. 2009), which supports the recognition of Cephalocassis and Hemipimelodus as valid genera, indicating a strong morphological convergence of lineages restricted to freshwater. The inclusion of Cephalocassis in the subtribe Ariina is supported by the MP and ML analyses.

Figures

Figure 1. MP analysis.Subfamilies (SF) Galeichthyinae (pink), Bagreinae (bright blue), and Ariinae (dark blue). Tribe (T) Ariini (blue), Cathopsini (orange), Genidentini tribe nov. (brown), and Sciadeini tribe nov. (light green).Subtribe (ST) Ariina (light blue) and Doiichthyina (green). Incertae sedis taxa (IS) (red). Numbers over branches correspond to the bootstrap support.

Figure 2. ML analysis. Subfamilies (SF) Galeichthyinae (pink), Bagreinae (bright blue), and Ariinae (dark blue). Tribe (T) Ariini (blue), Cathopsini (orange), Genidentini tribe nov. (brown), and Sciadeini tribe nov. (light green). Subtribe (ST) Ariina (light blue) and Doiichthyina (green). Incertae sedis taxa (IS) (red). Numbers over branches correspond to the bootstrap support.

Figure 3. BI analysis.Subfamilies (SF) Galeichthyinae (pink), Bagreinae (bright blue), and Ariinae (dark blue). Tribe (T) Ariini (blue), Cathopsini (orange), Genidentini tribe nov. (brown), and Sciadeini tribe nov. (light green).Subtribe (ST) Ariina (light blue) and Doiichthyina (green). Incertae sedis taxa (IS) (red). Numbers over branches correspond to the bootstrap support.

Figure 24. Representative skulls, in dorsal view, and distribution of the subtribe Ariina.A, Arius maculatus, AUM 44875. B, Cephalocassis melanochir, CAS 49426. C, Cryptarius truncatus, AUM 50243. D, Hexanematichthys sagor, AUM 50242. E, Kyataphisa nenga, AUM 46280. F, Osteogeneiosus militaris, AUM 44880. G, Pseudosciades sona, AUM 44861. * marine, ** brackish water, *** freshwater.

Figure 28. Cephalocassis melanochir, USNM 230311, Indonesia and Malaysia, type species of the genus.