Comprehensive DescriptionRead full entry
FIGURE 76. Pachyula crassilabris , Roberts, 1978. Lateral view.
Diagnosis. The combination of two shared characters distinguishes Pachyula ZBK from all other genera of the Ariidae : (1) accessory tooth plates absent (shared with Cephalocassis borneensis , Ketengus ZBK , Nedystoma ZBK , Potamarius izabalensis ZBK and Potamosilurus velutinus ); (2) posterior face of first epibranchial with a well developed process [shared with Plicofollis ZBK (with exception of P. platystomus )].
Supplementary morphological characters. Cephalic shield granulated visible under the skin; a moderately developed fenestra limited by lateral ethmoid and frontal visible under the skin; medial groove of neurocranium limited by frontal bones and/or on supraoccipital absent; posterior cranial fontanel moderately developed, long and narrow; fenestra limited by supraoccipital, pterotic and sphenotic absent; fossa limited by pterotic, supracleithrum and extrascapular relatively large; epioccipital invading dorsal portion of cephalic shield; occipital process triangular, very long and narrow, progressively narrower toward its posterior part; anterior and median nuchal plates fused and indistinct, forming a structure of semi-lunar aspect; tooth plates associated with vomer absent; accessory tooth plates absent; maxillary barbel fleshy and cylindrical; two pairs of mental barbels; base of adipose fin very long, as long as anal-fin base; lateral line not bifurcated at caudal region, reaching base of caudal-fin upper lobe; cleithrum wide with second dorsal process on its upper portion; posterior cleithral process very long and distinct from second dorsal process of cleithrum.
Remarks. Tetranesodon conorhynchus ZBK Weber, 1913 is the type-species of Tetranesodon ZBK and was not examined but included by possessing the diagnostic characters of the genus available in the literature. Thus, the inclusion of Tetranesodon ZBK as synonymous of Pachyula ZBK is tentative.
Distribution and habitat. Southern New Guinea, freshwaters.