Epigonus telescopus

Epigonus telescopus (Risso, 1810)

(English name: Black Cardinalfish; Black Deepsea Cardinal) (Figs. 1, 18; Tables 1–2)

Pomatomus telescopus Risso, 1810: 301, pl. 9 (original description; type locality: northwestern Mediterranean Sea, Nice, France; lectotype: MNHN B-0862); Lowe, 1838: 173 (list); Capello, 1868: 160; Moreau, 1881: 386, fig. 125; Vaillant, 1888: 376 (in part).

Epigonus macrophthalmus Rafinesque, 1810: 64 (original description; type locality unknown; types unknown).

Pomatomus telescopium Cuvier, 1828: 171 (incorrect emendation of Risso, 1810); Valenciennes, 1830: 495; Valenciennes, 1837–1844: 6 pl. I; Günther, 1859: 250; Günther, 1880: 395 (brief description); Cocco, 1885: 85; Holt & Calderwood, 1895: 405, pl. LXII.

Pomatomus cuvieri Cocco, 1829: 143 (original description; type locality: Messina, Sicily, Italy, Mediterranean Sea; types unknown).

Pomatomus cuvierii: Valenciennes, 1830: 501 (incorrect emendation of Pomatomus cuvieri in Cocco, 1829).

Epigonus telescopus: Goode & Bean, 1896: 232; Barnard, 1927: 523 (key and description, South Africa); Fowler, 1936: 736, fig. 326 (description, West Africa); Mayer, 1974: 152, fig. 2: (description, Atlantic Ocean and New Zealand); Mayer, 1975: 16 (brief description, South Atlantic); Gon, 1986: 559 (key and brief description, South Africa); Tortonese, 1986: 807 (brief description, North Atlantic and Mediterranean); Shcherbachev, 1987: 42 (list, Indian Ocean); Paulin et al., 1989: 180, fig. 113.5a (key, New Zealand); Mochizuki, 1990: 262 (description and photograph, New Zealand); Abramov, 1992: 98 (list); Gomon et al., 1994: 562 (key, Australia); Santos et al., 1997: 83 (list, Azores); Arruda, 1997: 82 (list, Azores); Saldanha & Biscoito, 1997: 199 (brief description, Mid-Atlantic Ridge); Bianchi et al., 1999: 166, pl. XI (Namibia); Biagi et al., 2002: (list, Mediterranean); Bilecenoglu et al., 2002: 81 (list, Turkey); Moore et al., 2003: 226 (list, western North Atlantic); Sartor et al., 2003: 278 (list, Mediterranean); Mytilineou et al., 2005: 231 (list, Ionian Sea); Hoese et al., 2006: 1115 (synonyms and distribution, Australia); Fricke et al., 2007: 82 (list, Turkey); Gomon et al., 2008: 564 (key and photograph, Australia); Bañon et al., 2010: 16 (list, Galicia); Møller et al., 2010: 58 (list, Greenland); Stewart & Gon, 2015: 1226 (key and description, New Zealand); Bañon et al., 2016: 322 (list, Galicia); Gon, 2016: 2434 (key and distribution, eastern Central Atlantic); Okamoto, 2016b: 74 (description and photograph).

Material examined. AMS I.28165-001, 3 specimens, 112.4–187.9 mm SL, 33°35´17˝S, 44°09´33˝E, Walters Shoal, western South Indian Ocean, 750 m depth, 18 December 1988; USNM 307603, 201.2 mm SL, 33°43´42˝S, 43°61´58˝E, Walters Shoal, western South Indian Ocean, 1,000–1,030 m depth, 17 December 1988; USNM 307608, 2 specimens, 137.8–154.3 mm SL, 33°37´42˝S, 44°10´42˝E, Walters Shoal, western South Indian Ocean, 750–775 m depth, 18 December 1988; unretained specimen, 720 mm SL, western South Indian Ocean.

Diagnosis. Dorsal-fin rays VII-I-I, 10; pectoral-fin rays 19–23; total gill rakers 23–26; vertebrae 11 + 14; pyloric caeca 21–34; pored lateral-line scales 46–50 + 3–5; opercular spine absent; maxillary mustache-like processes absent; ribs on last abdominal vertebra present; tongue toothless; body depth 22.7–25.5% SL.

Measurements (% SL); counts are given in Table 1. Head length 32.4–38.0; head width 16.8–19.2; head height 17.3–20.8; body depth 22.7–25.5; body width 15.9–18.9; caudal-peduncle depth 7.8–11.0; caudal-peduncle length 22.6–26.3; orbital diameter 8.8–17.1; interorbital width 9.9–11.2; postorbital length 11.1–15.2; upper-jaw length 13.7–15.5; lower-jaw length 15.1–19.1; snout length 7.3–9.7; pre-first dorsal-fin length 38.0–42.0; presecond dorsal-fin length 59.3–61.9; pre-pectoral-fin length 33.5–36.9; pre-pelvic-fin length 36.3–39.9; pre-anus length 60.9–66.3; pre-anal-fin length 67.2–70.7; first spine length on first dorsal fin 4.6–5.8; second spine length on first dorsal fin 11.9–12.9; third spine length on first dorsal fin 13.9–15.7; second dorsal-fin spine length 5.2–8.9; first anal-fin spine length 1.8–2.8; second anal-fin spine length 5.1–8.9; pelvic-fin spine length 7.5–12.1; first dorsal-fin base length 12.4–17.2; second dorsal-fin base length 9.8–11.1; anal-fin base length 8.3–13.0; pectoral-fin length 11.0–16.6; pelvic-fin length 13.3.

Distribution. Western South Indian Ocean (Shcherbachev 1987; Abramov 1992; present study); Eastern Atlantic including Mediterranean (Mayer 1974, 1975; Abramov 1992); western North Atlantic (Mayer 1974); Australia (Hoese et al. 2006; Gomon et al. 2008); New Zealand (Paulin et al. 1989; Stewart & Gon 2015), at ca. 75–1375 m depth.

Comparisons and Remarks. Epigonus telescopus belongs to the E. telescopus group by having an isolated dorsal-fin spine between first dorsal and second dorsal fins. The isolated dorsal fin spine reduces in size with growth, becoming difficult to discern in large adult specimens (Fig. 18). This species is similar to E. angustifrons in having the isolated dorsal-fin spine, but differs in having 23–26 gill rakers (vs. 33–36 in E. angustifrons) and a deeper body (ca. 1/4 of SL vs. ca. 1/5 of SL in E. angustifrons). Furthermore, E. telescopus differs from other congeners in the Western Indian Ocean in the absence of an opercular spine (vs. pungent opercular spine present in E. bispinosus, E. idai, E. lenimen, E. marimonticolus, E. pectinifer, E. robustus, and E. waltersensis) and 11 + 14 vertebrae (vs. 10 + 15 in E. denticulatus, E. elongatus, E. exodon, E. macrops, and E. marisrubri). Epigonus telescopus is the largest species of the genus (85 cm in total length) and long-lived with a maximum age about 100 years (Dunn 2009). In some area, this species is utilized commercially (Okamoto 2016b).