Comprehensive DescriptionRead full entry
Amatitlania nigrofasciata ( Guenther , 1867) , n. comb.
Heros nigrofasciatus Guenther , 1867 ZBK : 601 (original description).
Cichlasoma nigrofasciatum , Jordan & Evermann 1898: 1525 ( new combination ).
Archocentrus nigrofasciatus , Allgayer 1994: 15 ( new combination ).
Cryptoheros nigrofasciatus , Allgayer 2001: 15 ( new combination ).
Lectotype . BMNH 18184.108.40.206 , 64 mm SL (Fig. 18), O. Salvin . Designated herein from the largest specimen in the syntypic series. Lake Amatitlan , Guatemala (apparently not Lake Atitlán -see Remarks).
FIGURE 17. Distribution of the species in the genus Amatitlania . Squares, Am. nigrofasciata ; circle, Am. coatepeque ; triangles, Am. kanna ; stars, Am. siquia . A symbol may represent more than one collecting site.
Paralectotypes . BMNH 18220.127.116.11-78 (12), ZMB 6882 (1). There were several syntypes , not only one (see Remarks).
Diagnosis. No unique autapomorphies, but the only species in the genus with two (vs. one) distal rows of interradial scales on anal fin, and arms in the first epibranchial bone parallel (vs. divergent). In addition, posterior end of dentigerous arm of dentary rounded or squarish (vs. triple-spined or bluntly pointed). Peritoneal coloration uniformly dark (vs. not uniformly dark). Rostrad directed pronounced convexity on the ventral process of the articular absent (vs. present). Also morphometric differences (body less deep) vs. Am. kanna and Am. siquia , and coloration differences (4th bar not Y-shaped) vs. Am. coatepeque .
Description. D. XVII-XIX,7-9; A. VIII-X,6-7. Larger gill rakers elongated, rounded or pointed, curved ventrad. Scales from lateral line to base of first dorsal-fin ray modally 2.5; circumpeduncular scales usually 17-19, modally 18; total vertebrae 27-28 (further meristic data appear in Table 3).
Largest specimen examined 88 mm SL (maximum size 100 mm SL, according to Kullander 2003). Body depth 46-50% of SL, usually less than 48% of SL (further morphometric data appear in Table 4). Head profile nearly straight on orbits to convex on nape. Teeth conical, pointed. Upper symphysial teeth abruptly larger than adjacent teeth; lower symphysial teeth lower than adjacent teeth. Lips not medially narrow; lower lip often tapering, corner dorsally rounded, ventrally angled.
FIGURE 18. Amatitlania nigrofasciata , lectotype, BMNH 1818.104.22.168. Photo, BMNH, London.
Pectoral fins always reaching caudad beyond 2nd anal-fin spine, pelvic fins extending beyond 3rd anal-fin spine. Filamentous rays of dorsal fin to distal quarter of caudal fin. Up to two lateral-line pored scales on caudal fin, subsidiary scales usually present. Dorsal- and anal-fin interradial scale rows arranged in one or two rows, up to 8 scales long (contra Günther 1869, who found the soft dorsal and anal fins to have “scarcely any scales on their base”).
Gut simple, usually shorter than standard length of fish. Peritoneum silvery. Genital papilla tongueshaped, somewhat oval-tubular, slightly notched, tip bluntly triangular, not sunken; pigmented on margins, tip, and base on posterior (caudal) side.
Suborbital streak diffuse; stripe from snout to eye usually diffuse. Eyes bluish-green. Fourth bar on side of body I-shaped. Ocellus on spinous dorsal fin of females absent (present in 0.3% of the specimens examined). Breast olive. Axil of pectoral fin dark; base of pectoral fin usually definitely white. Caudal blotch present as a bar on fin, not on peduncle.
Distribution. The range of this species is restricted as follows: Pacific slope, from Río Sucio, El Salvador to Río Suchiate, Guatemala; Atlantic slope, from Río Patuca, Honduras to Río Jutiapa, Guatemala; in neither slope to Panama, Costa Rica or even Nicaragua, as formerly considered. Those southern populations, and the one isolated at Lake Coatepeque, El Salvador, belong to the three species described below (Fig. 17). Introduced elsewhere, e.g. in the Río Balsas basin, central Mexico (Contreras-Balderas 1999).
Remarks. Günther (1867) mentioned both lakes, Amatitlán and Atitlán , as the type locality; however, the original labels of the syntypes at BMNH mention only Lake Amatitlán , same as did Günther (1869). On the other hand, Eschmeyer (2005) mentions just two British syntypes, but there are 13 specimens in the jar (plus one skeleton), and Günther (1867) wrote: “numerous examples…were collected by Mr. Salvin.”
The extensive experimental (ethological, physiological, etc.) literature mentioning Archocentrus nigrofasciatus or Cichlasoma nigrofasciatum should eventually be revised regarding the origin of the material used (see Distribution). The same applies to the study of biological invasions by the “convict cichlid,” considered a potential pest outside its natural range (Welcomme 1988).