Microphilypnus Myers

Caires, Rodrigo A. & Figueiredo, José Lima De, 2011, Review of the genus Microphilypnus Myers, 1927 (Teleostei: Gobioidei: Eleotridae) from the lower Amazon basin, with description of one new species, Zootaxa 3036, pp. 39-57 : 40

Genus Microphilypnus Myers

Microphilypnus Myers, 1927: 134 [type-species: Microphilypnus ternetzi Myers, 1927 , by original designation].—Birdsong et al. 1988: 202 (Table 33; data from axial skeleton).—Hoese & Gill, 1993: 417, 423 (phylogenetic relationships of Eleotridae ).— Thacker et al. 2006: 495 (taxonomic remarks).

Diagnosis. Body minute (less than 25 mm SL), moderately compressed; first dorsal usually with six spines and second dorsal with 6–10 soft, segmented rays; teeth on jaws small, conical, in two or three rows anteriorly; cephalic sensory pores absent or, when present, restricted to preopercular and supraotic canals; cutaneous papillae system well developed, 5–7 vertical rows and 2 horizontal rows beneath eye; pelvic fin barely branched, inner rays separated; head long, compressed; lower jaw protruding; gill openings not united with isthmus, extending ventrally below vertical that passes through posterior margin of pupil; preopercular spine absent; trunk scales large, ctenoid, 23–32 in longitudinal series, 5–9 in transversal series and 8–13 in curcumpeduncular series; 2–15 scales present on predorsal region and opercle; vertebrae 11–13+14–17=26–29; pterygiophore formula of first dorsal fin 3(12210), 3(121110) or 3(22110).

Description. dorsal fin elements IV–VIII + 6–10, first dorsal fin separated from the second dorsal fin and about as large as second dorsal; anal fins rays 6–10; pectoral fin rays 11–15; segmented caudal fins rays 12-13; scales on longitudinal series 23–32; nape with large, partially embedded cycloid or ctenoid scales, sometimes partially naked; scales absent on breast, belly, pectoral base, but sometimes present on chin; opercle covered with cycloid or ctenoid scales; anterior nostril at end of a small, slender tube; posterior nostril a small hole; tongue emarginated, the tip free; gill opening extending ventrally below a vertical line intersecting rear margin of the pupil; caudal fin longer than deep, the posterior margin rounded to pointed; urogenital papilla longer than deep, slender, conical in males, bulbous, fimbriate in females. Gill rakers on lower limb 6–11, long to rudimentary; upper limb with 0–8 rudiments; teeth on jaws in 2–3 rows at middle of jaw, reduced to 1–2 rows laterally; teeth small, conical, no distinctly larger, caninoid teeth; cephalic sensory pores absent or, when present, restricted to preopercular (two POP pores on each side) and supraotic (one SOT pore on each side) regions. Head sensory papillae well developed, 5–7 vertical infraorbital rows, two horizontal infraorbital rows (rows b and d), two or three rows on interorbital region, three rows on opercle (rows oi, os, and ot).