Amatitlania coatepeque, Juan J. Schmitter-Soto, 2007

Juan J. Schmitter-Soto, 2007, A systematic revision of the genus Archocentrus (Perciformes: Cichlidae), with the description of two new genera and six new species., Zootaxa 1603, pp. 1-78 : 52-53

Amatitlania coatepeque , new species

Figures 17, 19

Cichlasoma nigrofasciatum (part. et non Günther), Hildebrand 1925: 274 (misidentification).

Holotype. UMMZ 245584 , 87 mm SL (Fig. 19), P. L. Clifton, Jan. 19, 1958. North shore of island in Lake Coatepeque , El Salvador.

Paratypes. FMNH 12136 (10), island in Lake Coatepeque ; UMMZ 181823 (18), 202805 (4), Santa Ana, eastern coast of Lake Coatepeque at Monterrey .

Diagnosis. Unique autapomorphies (fig. 24h in Schmitter-Soto, in press): fourth bar on side of body Y- shaped (formed by ventral coalescence of 4th and 5th bars) (vs. I-shaped); posterior end of dentigerous arm of dentary triple-spined (vs. rounded), squarish or bluntly pointed; and a characteristic double medial-loop in gut present (vs. absent). Differs from the other Amatitlania species also by posteriad projection at dorsal corner present in lower lip (vs. absent), peritoneal pigmentation uniformly sparse (vs. uniformly dark or silvery), and scales from lateral line to origin of dorsal fin 5-5.5 (vs. 5 or fewer).

Description. D. XVII-XIX,7-9; A. VIII-X,6-7. Scales from lateral line to first dorsal fin ray modally 2; circumpeduncular scales usually 17-18; total vertebrae 28 (additional meristic data appear in Table 3).

Largest specimen examined 91 mm SL. The most slender Amatitlania , body depth 43-48% of SL, usually less than 47% of SL (further morphometric data appear in Table 4). Head profile concave to straight on orbits to convex on nape. Teeth conical. Upper symphysial teeth usually subequal to adjacent teeth. Upper lip medially narrow; lower lip tapering or not, rounded at corner, sometimes with a dorsal posteriad projection.

Pectoral and pelvic fins sometimes not reaching 1st anal-fin spine, but usually extending caudad beyond 2nd anal-fin spine Filamentous rays of dorsal fin to end of caudal fin. One or two pores continuing lateral line on caudal fin, subsidiary scales forming rows between other caudal-fin rays. Dorsal-fin interradial scales arranged in one row, anal-fin scales in one or two rows, both up to 8 scales long.

Gut simple with a double medial-loop and the anal loop turned dorsad, always longer than standard length of fish. Peritoneum with uniformly distributed melanophores among others, larger, fewer, aligned with ribs; in young, only rostrally pigmented. Genital papilla elongated, contours parallel, end somewhat crenulated; pigmented on margins, base, tip, and posterior (caudal) side.

No suborbital streak discernible; stripe from snout to eye usually diffuse. Head bar darkening the whole opercle, except for area rostral to lateral line. Eyes bluish-green. Bars on side of body more intensely black than other Amatitlania ; 4th bar Y-shaped, coalescent ventrally with 5th. Sometimes three rows of hyaline spots, on tip of soft dorsal and base of soft anal fins. Breast olive-blackish. Axil of pectoral fin dusky; base of pectoral fin whitish or with same coloration as breast. Caudal blotch present as a bar on fin, not on peduncle, nearly all across the depth of the fin.

Distribution. Known only from the type locality, Lake Coatepeque, El Salvador (but see Remarks) (Fig. 17; photographs in Hildebrand 1925, his figs. 3 and 4).

Etymology. Coatepeque is the name of the lake where the species occurs, likely formed from the Nahuatl cóatl =snake and tépetl =mount, hence “mount of the snake.” A noun in apposition.

Remarks. In his study of Salvadorian fishes, Hildebrand (1925) included specimens of Cichlasoma nigrofasciatum from Lake Coatepeque; the species was “especially abundant among the rocks where, because of the very clear water, it could be seen at a depth upward of 6 meters.” He noted that “some specimens are much darker than others”, and that the natives called the light variety “plateada” (silver) and the dark one “negra” (black). Am. coatepeque has much more intense bars on side of body than other Amatitlania species.

The population at Lake Chalchuapa, El Salvador (FMNH 12139), although identifiable on other respects as Am. nigrofasciata , displays in 2 of 7 individuals the Y-shaped 4th bar characteristic of the new species. The site is near Lake Coatepeque, and may have been connected to it in the past. The above mentioned “plateada” and “negra” forms coexist at Chalchuapa ( Hildebrand 1925).