Epigonus marimonticolus Parin & Abramov 1986

Epigonus marimonticolus Parin & Abramov, 1986

(New English name: Silver Cheek Deepwater Cardinalfish) (Figs. 3, 14; Tables 1, 2)

Epigonus marimonticolus Parin & Abramov, 1986a: 53, fig. 1 (original description; type locality: 10°18 S, 56°03 E, West of Agalega Shoals, western Indian Ocean, 400–420 m depth; holotype: ZIN 47133); Shcherbachev, 1987: 42 (list, Arabian Sea, western Indian Ocean); Abramov, 1992: 99 (list); Manilo & Bogorodsky, 2003: (list, Arabian Sea); Okamoto, 2012: 307, fig. 10 (key and photograph, western South Indian Ocean).

Material examined. LACM 44723-3, 6 specimens, 109.8–139.0 mm SL, 10°19.0 S, 59°08.5 E, western South Indian Ocean, 395–420 m depth, 14 January 1989; USNM 307605, 4 specimens, 129.0– 146.6 mm SL, data same as for LACM 44723-3.

Diagnosis. Dorsal-fin rays VII-I, 10; pectoral-fin rays 20–22; total gill rakers 29–32; vertebrae 10 + 15; pyloric caeca 12–14; pored lateral-line scales 45–48 + 3–4; scales below lateral line 11; pungent opercular spine present; maxillary mustache-like processes absent; ribs on last abdominal vertebra absent or rarely reduced ribs present; nub-like structures on symphysis of lower jaw absent; tongue toothless.

Measurements (% SL); counts are given in Table 1. Head length 36.2–39.1; head width 15.6–18.5; head height 13.1–16.7; body depth 19.1–23.0; body width 13.0–15.7; caudal-peduncle depth 8.6–9.7; caudal-peduncle length 23.8–25.6; orbital diameter 15.5–17.1; interorbital width 7.0–8.9; postorbital length 14.0–16.6; upper-jaw length 12.8–14.3; lower-jaw length 15.2–16.6; snout length 6.2–7.6; pre-first dorsal-fin length 36.8–38.8; presecond dorsal-fin length 59.0–62.2; pre-pectoral-fin length 35.4–38.4; pre-pelvic-fin length 36.2–38.8; pre-anus length 56.8–60.4; pre-anal-fin length 66.5–76.1; first spine length on first dorsal fin 2.0–3.1; second spine length on first dorsal fin 14.7–17.0; third spine length on first dorsal fin 15.2–19.0; second dorsal-fin spine length 8.0–9.6; first anal-fin spine length 2.2–3.3; second anal-fin spine length 8.1–11.1; pelvic-fin spine length 12.5–14.5; first dorsal-fin base length 11.5–14.0; second dorsal-fin base length 10.0–11.4; anal-fin base length 9.5–10.8; pectoralfin length 13.4–16.3; pelvic-fin length 16.0–18.8.

Distribution. Arabian Sea; western South Indian Ocean (Parin & Abramov 1986a; Okamoto 2012), at 395– 420 m depth.

Comparisons and Remarks. Epigonus marimonticolus belongs to the E. constanciae group by having a pungent opercular spine (Fig. 14). This species is most similar to E. bispinosus in the study area; however, E. marimonticolus differs from E. bispinosus in lacking spines on the symphysis of the lower jaw and a pair of ribs on the last abdominal vertebra (see Figs 5, 6A). Also, E. marimonticolus is similar to E. idai in having 10 soft rays in the second dorsal fin; however, it differs in having 20–22 pectoral fin rays and lacking a pair of ribs on the last abdominal vertebra (vs. 18–19 pectoral fin rays and ribs present on the last abdominal vertebra in E. idai, see Fig. 11C). Epigonus marimonticolus can be distinguished from the remaining 4 species of the E. constanciae group of the Western Indian Ocean in having 10 soft rays on the second dorsal fin and 12–14 pyloric caeca (vs. 9 soft rays and 5–10 pyloric caeca in E. lenimen, E. pectinifer, E. robustus, and E. waltersensis). In their ichthyofaunal study of the Arabian Sea, Manilo & Bogorodsky (2003) listed only E. marimonticolus for the Epigonidae.