1) Amphilophus labiatus (Günther, 1864);

Cichlidae .

Red Devil; Mojarra Picuda, Diablo Rojo (Figs. 2A–B).

Diagnosis: This species differs from the other species of the family occurring in the freshwaters of the country by the following combination of characters: teeth pointed, conical, without second cusp on premaxillary and mandibular teeth of the 1st series; lips thick and large, the lower lip continuous, without a frenum (see Bussing 1998); cheek scale series 4–5 (see Říčan et al. 2016); dorsal fin spines 16–17; and anal fin spines 6–7. Furthermore, A. labiatus differs from the closely related Amphilophus citrinellus (Günther, 1864) by having a larger (37.8–39.5% of Standard Length – SL; vs. 35.0–35.6% of SL) and thinner (Head Depth – HD = 79.9–90.9% of Head Length – HL; vs. HD = 111.5–118.9 of HL) head and a larger (42.8–43.4% of HL; vs. 40.4–41.9% of HL) snout. See Stauffer & McKaye (2002) for a detailed comparative analysis.

Basis of the record: A single specimen was captured in the río San Juan, San Carlos, Alajuela (ca 10.89057, -84.26540), at ca 26 m. a.s.l., in November 2020, by an anonymous angler. Additional specimens, identified as A. labiatus, are deposited at the fish collection of the UCR (0122-014, 0240-001, 0429-002 and 0804-005).

Remarks: Previous records in the country of this species have been assigned to the closely related A. citrinellus . This species prefers lacustrine environments, being more abundant in the Lake Nicaragua; it has rarely been captured in lotic environments (Bussing 1998). As in A. citrinellus, a polychromatism has been described for this species; with a cryptic form (grey or brown with dark bars or spots; i.e., the normal morph) and a conspicuous form (which lacks melanophores, resulting in brightly red, orange, or yellowish colored fish; i.e., the gold morph), both occurring naturally (Barluenga & Meyer 2004).