Comprehensive DescriptionRead full entry
Rocio , new genus
Parapetenia , Allgayer 1989: 26 (part.).
Archocentrus , Schmitter-Soto 1998: 154 (part.).
Diagnosis. Three strict synapomorphies (figs. 2e, 6e and 7e in Schmitter-Soto, in press): main gill rakers on first arch with a mediad projection at base; posterior edge of mesethmoid with an indentation and a posteriad spine; posterior edge of supraoccipital crest undulated, with a deep concavity. Many homoplastic synapomorphies: first dorsal fin ray not divided; ascending premaxillary process to anterior orbit rim (also in Amatitlania ); lower symphysial teeth usually bicuspidate (also in Cryptoheros ZBK ); narrowest point of dentigerous arm of premaxilla at caudal tip; scale rows between lateral line and base of first dorsal fin ray modally 3.5 or more (also in Ar. spinosissimus ); first bar on side of body Y-shaped but diffuse (also in some Archocentrus , some Cryptoheros ZBK , and Tomocichla ZBK ); longitudinal stripe from orbit to lateral blotch (also in Ar. spinosissimus and P. loisellei ).
Description. D. XVII-XIX,8-11; A. VIII-IX (rarely VI, VII, or X),7-9 (rarely 6); pectoral 14-16. Lower gill rakers 6-8 (rarely 9); main gill-rakers with low ridges directed posteriad. Scales weakly ctenoid (almost cicloid) to strongly ctenoid. Interradial scale rows in dorsal and anal fins, up to 8 scales long, usually in one row. Scales from lateral line to first dorsal fin spine 3.5-5.5; pored lateral-line scales (not counting scales overlapping between the two segments of the lateral line) 27-31, prolonged by up to two pored scales on caudal fin; scales from lateral line to first dorsal fin ray 2.5-4, rarely 4.5; scales between vent and interpelvic scale 7-15; circumpeduncular scales 17-22. Procurrent rays of caudal fin two; anal creases modally 14; vertebrae15-17 caudal, 28-30 total. Said to reach 250 mm SL (Page & Burr 1991), usually much smaller. Body rather oval in young, almost Archocentrus-like; more elongate in adults, almost Parachromis-like. Premaxillary dorsal process to anterior rim of orbit. Lower jaw extending beyond upper jaw; frenum present in lower lip; lips not medially narrow. Teeth moderately embedded; upper symphysial canine or conical, unicuspid or with a lingual cusp, abruptly larger than adjacent teeth; lower symphysial teeth lower than adjacent teeth. Origin of pelvic fin behind origin of dorsal fin. Caudal fin rounded-truncate. Gut simple all life long. Peritoneum almost immaculate, except for some melanophores dorsally on anteriormost ribs. Genital papilla oval, longer than wide, tip bluntly triangular in males, in females opening oval and not much crenulated, sunken; pigmented just on base, on margins, or not at all. Two usually well-marked interorbital bands; a sharp vertical bar on head, across all of opercle and nape, opercular spots part of it; cheeks, opercular and gular regions often speckled. A longitudinal stripe from snout through orbit and opercle to lateral spot on 3rd or 4th lateral bar; 8 bars on sides (sometimes rather indistinct), first bar diffusely Y-shaped, 4th and sometimes also 3rd bar medially more intense. Bars on side of body not extending onto dorsal and anal fins; 3-6 rows of dots on bases of soft dorsal and anal; no dorsal ocellus or abdominal blotch in mature females; ocellated spot on caudal fin, completely dorsal to lateral line.
Distribution. Atlantic versant, from Honduras to Mexico, as far north as Veracruz (Fig. 22).
Species composition. Three species: R. octofasciata , R. ocotal , R. gemmata .
Etymology . The gender is feminine: Rocío is my wife’s name. The Spanish word “ rocío ” means “morning dew”, an image evoked by the resplendent spots on cheek and sides of some species, notably R. gemmata .