Diagnosis |
This species is distinguished from its congeners by the following characters: absence of a sexual dichromatism of the caudal fin (vs. caudal fin of females with a distinctively marked dorsal blaze), markedly inflated pores in the laterosensory system of the head, jaws, suspensorium and infraorbital series; it has 5 separate infraorbital elements (vs. 4), and a robust lower pharyngeal jaw (versus a markedly more gracile element in congeners). Uniquely among congeners, T. obamaorum is a robust species lacking dorsoventral head and body depression; it is further readily distinguished from T. monogramma by number of anal spines (7-8 vs. 4), and from T. brichardi in the possession of 32-35 pored lateral-line scales (vs. 51-60) (Ref. 104438).
Description: Body deep and laterally compressed, with greatest depth at level of first dorsal fin spine; dorsal and ventral body profiles slightly convex to relatively short, deep, caudal peduncle; head robust rather than dorsoventrally compressed; adductor mandibulae muscle complex markedly enlarged lending bulging appearance to the cheeks. Snout prominent and bears single, tubular, nostril on either side; snout and dorsal head profile rise at angle of 35°-40° to midorbit, often with small, fat-filled, nuchal hump just anterior to dorsal fin origin in both sexes. Jaws prominent, slightly prognathous and robust with lips well developed and fleshy; inner and outer row teeth of both jaws pointed unicuspid; single series of 2-3 enlarged, recurved canines situated anteriorly on premaxilla; dentary with 3 enlarged canines anteriorly, larger pair slightly displaced dorsolaterally; remaining outer row of teeth in both jaws gradually taper in size and extend almost entire length of both jaws; 4 or 5 inner rows of small, slightly recurved, unicuspid teeth clustered on anterior third of dentary; no inner rows distally on lower jaw; two or three inner tooth rows anteriorly on premaxilla, tapering to single row; terminating at two-thirds of length of dentigerous arm. Lower pharyngeal jaw is markedly more robust than in congeners with slightly sinuous, rather than straight, ventral suture; usually 15-16 moderately robust, unicuspid teeth in posterior row; symphysial teeth enlarged and somewhat molariform. Gill rakers elongate, nondenticulate and slender. Dorsal-fin spines gradually increase in length posteriorly to around 8th spine then coequal in length; posteriormost branched fin rays of dorsal and anal fins reach to anterior third of caudal fin; caudal fin large and paddle shaped, with 14-branched rays (7+7) and rounded symmetrical distal margin; pectoral fins broadly fan shaped, long but falling short of anus, with 15-16 rays; pelvic fins falling just short of anus, with third branched ray longest in both sexes. All scales cycloid, with those on flanks small and somewhat irregularly sized; entire head and nape proximal to dorsal-fin origin naked; pectoral base and chest naked, scales over ventrum to anus very small and deeply embedded; scales immediately below dorsal-fin fold to level of 10-12th dorsal-fin spine markedly smaller than those on flanks; proximal third of caudal fin covered with small ovoid, scales; lateral line continuous and undivided; comprised of 32-35 elongate, pored scales, each approximately twice as large as unpored scales of upper and lower flanking rows; often 1 or 2 pored scales embedded distal to line of caudal flexion on caudal base (Ref. 104438).
Coloration: Males and females are similarly colored in life with base body coloration uniform smoky, grayish black becoming pale yellowish gray ventrally. In preservation, the base body coloration is dark brownish black, slightly darker dorsally becoming paler ventrally; unpaired fins are uniformly blackish brown (Ref. 104438). |