Diagnosis: Ptychochromoides vondrozo is distinguished from congeners by the lack of a prominent adipose occipital hump, even in large adults and regardless of sex (Ref. 39915). In life, Ptychochromoides vondrozo is diagnosed by a vivid golden-olive ground colouration in combination with an irregular, brownish to black, blotchy and speckled lateral pigmentation pattern (Ref. 39915). It is further distinguished from its sister taxon, Ptychochromoides betsileanus by possession of a shallower caudal peduncle, 12.9-14.8% of standard length vs. 15.8-18.1%; a noticeably convex lateral snout outline with conspicuous premaxillary pedicel prominence; and a higher modal vertebral count, 30 vs. 29 (Ref. 39915). It is distinguished from Ptychochromoides katria by a larger adult size, exceeding 200 mm standard length; a mottled and blotchy overall pigmentation pattern vs. solid golden-brown base body colouration, with two wide, black vertical bars on the flanks; a greater number of ceratobranchial gill rakers, 10-12 vs. 8-9; the absence of a hypertrophied cephalic latero-sensory canal system on the lower jaw, preopercle, and neurocranium; and the presence of cycloid scales on the chest and belly vs. cycloid scales restricted to the extreme antero-ventral margin of the chest (Ref. 39915).

Description: The body is laterally compressed (Ref. 39915). In lateral view, the jaws generally range from isognathous to slightly retrognathous, but are moderately retrognathous in some specimens; the mouth has a somewhat beaked appearance, owing to possession of a convex lateral snout outline and well-developed fleshy lips; the lips are covered with tiny, fleshy papillae (Ref. 39915). The predorsal head profile is curved from approximately the level of mid-orbit to origin of the dorsal fin (Ref. 39915). Ptychochromoides vondrozo is characterized by an elongate premaxillary ascending process, extending approximately to a vertical through the anterior margin of the orbit, producing a prominent premaxillary pedicel protuberance; the supraoccipital crest is elongate, with a relatively smooth suture and no dorso-medial gap between the frontal bones and supraoccipital (Ref. 39915). The predorsal head profile, even in the largest specimens, is not characterized by a pronounced adipose occipital hump; any dorsal occipital projection in the new species is due entirely to the shape of the underlying supraoccipital and frontal bones, and not to an accumulation of adipose tissue in this region (Ref. 39915). Buccal dentition generally consists of very closely set, distally expanded, bilaterally symmetrical bicuspid teeth; oral teeth usually range from very weakly to strongly bicuspid, but may be unicuspid posteriorly in the upper and lower jaws; dentition covers anterior 3/4 of the premaxillary arcade, and well over anterior 1/2 of the dentary; outer row teeth are enlarged and graded in size laterally; anteriormost teeth in both upper and lower jaws are implanted procumbently, and in the upper jaw these rostral teeth are slightly recurved near the crown; posteriormost teeth in the upper and lower jaws are unicuspid to weakly bicuspid; both upper and lower jaws with two or four inner rows of much smaller, bilaterally symmetrical, bicuspid teeth; inner row teeth are morphologically similar to the outer row, except posteriorly, where dentition ranges from unicuspid to weakly bicuspid; lips of the upper and lower jaws are well developed and fleshy (Ref. 39915). The lower pharyngeal jaw is robust and covered anteriorly with straight to slightly curved, coarse unicuspid teeth, and postero-laterally with weakly hooked, bicuspid teeth; teeth are more numerous posteriorly on the lower pharyngeal jaw; teeth becoming increasingly robust medially on the lower pharyngeal jaw, and are molariform centrally on the posterior half of the lower pharyngeal plate; the lower pharyngeal jaw is wider than long, and is fully sutured, with numerous interdigitations, along its postero-ventral margin; teeth on pharyngobranchial 3 are hooked and bicuspid laterally, and molariform medially; only a single row of dentition is present on an elongate second pharyngobranchial toothplate, characteristic of the genus; teeth on this toothplate are large, hooked and bicuspid (Ref. 39915). There are 10-12 elongate gill rakers arrayed along the lower limb of the first gill arch, including the raker in the angle of the arch; ceratobranchial rakers on the first gill arch are denticulate medially, whereas other ceratobranchial rakers are strongly denticulate dorsally; epibranchial rakers are elongate and range from 5-8; in individuals with 7-8 epibranchial gill rakers, the most dorsal one or two rakers are extremely reduced and difficult to detect; the pseudobranch ranges from somewhat to fully exposed and gill-like; well-developed toothplates are present on the dorsal surface of the 4th ceratobranchial bones, and are confluent with the outer row of rakers; morphology of dentition on these toothplates ranges from elongate, conical, unicuspid teeth laterally, to very weakly hooked and bicuspid teeth along the medial margins of the toothplates (Ref. 39915). The caudal peduncle is shallow, narrow, and elongate; the urogenital papilla of larger males and females is enlarged and possesses numerous small tassels (Ref. 39915). The dorsal fin has 13-15 spines and 10-13 soft rays; the anal fin has 3 spines and 9-10 soft rays; the first anal spine is very short, frequently greatly reduced in length, whereas the second and third spines are elongate and nearly equal in length; the soft dorsal and anal fins are relatively produced, and may extend to or slightly beyond the origin of the caudal fin, however, trailing margins of these fins are not filamentous; origin of the dorsal fin is located well posterior to a vertical through pectoral fin insertion, and somewhat anterior of a vertical through pelvic fin insertion; the pectoral fins are large and elongate, and do not extend to a vertical through the anus; the pelvic fins are short and do not reach the anus in smaller specimens; in larger specimens, the pelvic fins extend to or slightly beyond the anus; te caudal fin is weakly to moderately emarginate, and the dorsal and ventral lobes are rounded and not produced (Ref. 39915). The body is covered with large and regularly imbricate scales from approximately mid-orbit to origin of the caudal fin; the body is scaled except the snout, lachrymal, preopercle, and the dorsal and rostral margins of the opercle; scales on head, cheek, nape, opercle, ventral chest, and belly are cycloid; lateral body scales are cycloid to about the level of mid-dorsal fin dorsal to the upper branch of the lateral line, and to approximately 3/4 the length of the pectoral fin rays when adducted, below the upper branch of the lateral line; posteriorly, lateral body scales become increasingly ctenoid, and remain ctenoid to the origin of the caudal fin; scales on the caudal fin, posterior of the hypural flexure, are usually cycloid and reduced in size (Ref. 39915).

Colouration: Overal ground colouration in life is bright golden-olive; the flanks, cheek, and head are covered with irregular brownish-black blotches and speckles, the degree and intensity of blotching and speckling is highly variable; the body is dark brown dorsally, becoming dark greyish-black to black along the dorsal midline and below the dorsal fin base; there is a distinctive bright golden patch located centrally on the opercle, and the cheek and region posterior of the orbit are also golden; the snout, anterior of the chest, and sections of the belly range from dark brown to black; there is a narrow yellow band around the eye, and the lips range from light grey to dark greyish-brown; a distinct solid black patch is present immediately posterior to, and extending somewhat dorsally from, pectoral fin insertion; there are two prominent brownish-black blotches, one located dorsally and the other ventrally, near the origin of the caudal fin; these black patches are preceded anteriorly by a wide, light golden-olive, vertical bar (Ref. 39915). The dorsal and anal fins are dark brownish-black proximally, followed by a wide pinkish bar, and are blackish distally; the caudal fin is dark greish-brown proximally, followed by a light, somewhat translucent pinkish band, and is darker pink distally; the terminal margin of the caudal fin is pink, except centrally where it is greyish-black; the pelvic fins are brownish-black, becoming lighter distally, and the pectoral fins are muted pink and translucent, except proximally where they are greyish-black (Ref. 39915).