Hypsophrys nicaraguensis

Hypsophrys nicaraguensis (Günther, 1859)

Figures 27-28

Hypsophrys unimaculatus Agassiz, 1859: 408 (nomen nudum, but see Remarks).

Heros nicaraguensis Günther, 1864: 153 (original description).

Heros balteatus Gill in Gill & Bransford, 1877: 184 (junior synonym).

Cichlasoma nicaraguense, Pellegrin 1904: 167 (new combination).

Cichlasoma spilotum Meek, 1912: 73 (junior synonym).

Hypsophrys nicaraguensis, Kullander 1996: 195 (new combination).

Copora nicaraguense, Fernández-Yépez 1969: 3 (new combination).

Holotype. BMNH 1867.9.23.37, 141 mm SL (Fig. 28), J. M. Dow. Lake Nicaragua, Nicaragua. No paratypes.

Diagnosis. Unique autapomorphies (Schmitter-Soto, in press): first dorsal fin ray spiniform; pharyngeal jaws 19 teeth rows wide, 11 rows long; gill rakers on lower limb of first arch modally 9. Easily distinguished from the other species in the genus by the pointed jaw teeth and the strongly convex head profile (“Coryphaena-like ”- Günther 1869), among many other differences.

Description. D. XVIII-XIX (modally XIX),9-11; A. VII-VIII,7-9 (modally VIII,8); pectoral 15-16. First dorsal fin ray not divided. Gill rakers on lower limb of first arch 9-10; gill rakers long, arched, may be bifid. Subsidiary pored scales on caudal fin in two long rows between rays. Scale rows on cheek 4-5 (contra Günther 1869, who counted 6); pored lateral-line scales (not counting scales overlapping between the two segments of the lateral line) 31-33; scales from lateral line to origin of dorsal fin 5-5.5; scales from vent to interpelvic scale 9-12; anal creases modally 12 (additional meristic data appear in Table 3).

Largest specimen examined, 141 mm SL, but grows at least to 165 mm SL (Kullander 2003). Body depth 44-46% of SL (further morphometric data appear in Table 4). Teeth moderately embedded, at least lateral teeth; symphysial teeth small, conical, narrow, slightly retrorse; upper symphysial teeth not abruptly larger than adjacent teeth, lower subequal. Lips not medially narrow; lower lip at corner of mouth square-rounded or slightly tapering.

Pelvic fins inserted behind origin of dorsal fin. Pectoral fins often falling short of first anal-fin spine; pelvic fins always reaching at least to 3rd anal-fin spine. Caudal fin profile emarginate to subtruncate. Scales moderately ctenoid, rather deciduous.

Gut simple; gut length ca. 80% of SL. Genital papilla rounded, wider than long, almost triangular, may be smaller than creased area of anus; immaculate or a few melanophores on basal margins.

No stripe from snout to eye. Eyes greenish. Six bars on sides, diffuse; a conspicuous, rounded lateral blotch, on 4th bar; a diffuse longitudinal bar from orbit to caudal fin, in which there may be a faint blotch on fin, above lateral line (often absent). Dots on fins (often not noticeable in young). Rows of spots on sides 13- 15, smaller than scales; breast olive-yellowish. Axil of pectoral fin darkened, especially dorsally; base of pectoral fin whitish.

Distribution. Ríos Sapoá, Pizote, and Chirripó-Matina, Costa Rica, north to lakes Managua and Nicaragua and Río Coco, Nicaragua (Fig. 28).

Remarks. The list of objective synonyms highlights the uncertain generic affinities of the species. However, its relationship to H. nematopus is supported not only by the present morphological study, but also by several recent molecular phylogenies (Martin & Bermingham 1998; Hulsey et al. 2004; Concheiro Pérez et al. 2007).

The entire original description of H. unimaculatus Agassiz, 1859 from Lake Nicaragua gives no other detail but that it “resembles Chrysophrys ” (= Sparus aurata Linnaeus), a Mediterranean and north Atlantic coastal fish (Eschmeyer 2005). Nevertheless, Kullander and Hartel (1997) explained how this simple statement leaves no doubt that the species involved is H. nicaraguensis (the only species in Lake Nicaragua to have an oval lateral blotch similar to that of Chrysophrys).

Because there are no types of H. unimaculatus and the name constitutes a senior synonym unused after 1899 (ICZN 1999), I shall file a petition to ICZN to conserve the younger specific epithet nicaraguensis.