Epigonus denticulatus Dieuzeide, 1950

Okamoto, Makoto & Gon, Ofer, 2018, A review of the deepwater cardinalfish genus Epigonus (Perciformes: Epigonidae) of the Western Indian Ocean, with description of two new species, Zootaxa 4382 (2), pp. 261-291 : 271

Epigonus denticulatus Dieuzeide, 1950

(English name: Pencil Cardinal, White Deepsea Cardinal) ( Figs. 2 , 8 ; Tables 1, 2)

Epigonus denticulatus Dieuzeide, 1950: 89 , fig. 1 (original description; type locality: Algeria, southwestern Mediterranean Sea, 100–500 m depth; types unknown); Mayer 1974: 175, fig. 13 (description, Japan, New Zealand, Australia, Gulf of Mexico, Caribbean Sea, Mediterranean, west coast of Africa); Mochizuki, 1982: 226 (description and photograph, Kyushu-Palau Ridge, southern Japan); Mochizuki & Shirakihara, 1983: 205, fig. 5A (key and photograph, Japan); Mochizuki, 1984: 151 (brief description, Japan); Machida, 1985: 484 (description and photograph, Okinawa Trough, southern Japan); Tortonese, 1986: 806 (brief description, Mediterranean and eastern North Atlantic); Gon, 1986: 558 (key and brief description, South Africa); Shcherbachev, 1987: 42 (list, South West Indian Ocean); Allen & Cross, 1989: 553 (list, Australia); Paulin et al., 1989: 180 (key, New Zealand); McAllister, 1990: 141 (list, Canada); Mochizuki, 1990: 258 (brief description and photograph, New Zealand); Abramov, 1992: 98 (key); Gomon et al., 1994: 562 (key, brief description and photograph, Australia); Mochizuki, 1997: 306 (brief description and photograph, Japan); Shinohara & Matsuura, 1997: 303 (list, Suruga Bay, Japan); Bianchi et al., 1999: 166 (list, Namibia); Fricke, 1999: 236 (list, Western Indian Ocean); Shinohara et al., 2001: 323 (list, Tosa Bay, southern Japan); Pakhorukov, 2001: 379 (list, Atlantic Ocean); Biagi et al., 2002: 236 (list, Mediterranean); Bilecenoglu et al., 2002: 81 (list, Turkey); Hayashi, 2002: 780 (key, Japan); Gon, 2003: 1394 (key, Western Central Atlantic); Moore et al., 2003: 225 (list, western North Atlantic); Shinohara et al., 2005: 432 (list, Ryukyu Islands, southern Japan); Mundy, 2005: 358 (list, Hawaiian Islands); McEachran & Fechhelm, 2005: 237 (list, Mexico); Hoese et al., 2006: 1114 (list, Australia); Fricke et al., 2007: 82 (list, Turkey); Gomon et al., 2008: 562 (list, Australia); Fricke et al., 2009: 53 (list, Western Indian Ocean); Tokimura et al., 2009: 405 (brief description, East China Sea); Ruiz- Pico et al., 2012: 578, fig. 1 (description and photograph, Spain); Hayashi, 2013: 780 (key, Japan); Okamoto & Motomura, 2013: 309, fig. 9-b (key and photograph); Stewart & Gon, 2015: 1221, fig. 172.1 (description and photograph, New Zealand); Bañon et al., 2016: 322 (list, Spain); Gon, 2016: 2433 (key and list, eastern Central Atlantic).

Epigonus atherinoides (not of Gilbert): Kuroda, 1951: 331 (list, Suruga Bay, Japan); Kamohara, 1964: 39 (list, Kochi Prefecture, southern Japan); Chen, 1980: 323, pl. VI-31 (list and photograph, Emperor Seamounts).

Material examined. SAIAB 193759 , 120.0 mm SL, 34°11 S, 25°17 E, St. Francis Bay , Eastern Cape, South Africa, date unknown ; SAIAB 20561 , 145.0 mm SL, 35°53 S, 20°57 E, southeast of Cape Agulhas , Western Cape, South Africa .

Diagnosis. Dorsal-fin rays VII-I, 10; pectoral-fin rays 18–21; total gill rakers 28–34; vertebrae 10 + 15; pyloric caeca 10–14; pored lateral-line scales 45–49 + 3–5; opercular spine absent; maxillary mustache-like processes absent; nub-like structures or spine on symphysis of lower jaw absent; ribs on last abdominal vertebra present; tongue toothless or rarely small tooth patch present; pectoral fin not reach level of origin of second dorsal fin, pectoral-fin length 14.1–19.9 % SL.

Measurements (% SL); counts are given in Table 1. Head length 32.4–35.7; head width 14.8–16.2; head height 15.1–17.4; body depth 18.0–21.4; body width 12.4–15.3; caudal-peduncle depth 8.3–9.8; caudal-peduncle length 27.5–30.8; orbital diameter 13.3–15.9; interorbital width 8.1–9.6; postorbital length 12.1–14.9; upper-jaw length 13.5–15.7; lower-jaw length 15.3–17.8; snout length 6.4–8.0; pre-first dorsal-fin length 36.2–38.6; presecond dorsal-fin length 56.3–61.0; pre-pectoral-fin length 32.0–35.6; pre-pelvic-fin length 33.0–35.7; pre-anus length 54.0–57.4; pre-anal-fin length 62.0–65.5; first spine length on first dorsal fin 2.5–4.1; second spine length on first dorsal fin 10.2–13.3; third spine length on first dorsal fin 12.4–14.1; second dorsal-fin spine length 5.5–7.7; first anal-fin spine length 2.1–3.3; second anal-fin spine length 5.3–7.9; pelvic-fin spine length 7.3–10.4; first dorsal-fin base length 10.3–13.3; second dorsal-fin base length 8.6–11.5; anal-fin base length 8.1–10.9; pectoral-fin length 14.1–19.9; pelvic-fin length 12.2–15.6.

Distribution. Western South Indian Ocean (Shcherbachev 1987; Abramov 1992); Gulf of Mexico ( Mayer 1974; McEachran & Fechhelm 2005); Caribbean Sea ( Mayer 1974); Eastern Atlantic including Mediterranean ( Dieuzeide 1950; Mayer 1974; Abramov 1992; Ruiz-Pico et al. 2012); Tasman Sea, Australia and New Zealand (Paulin et al. 1989; Abramov 1992; Stewart & Gon 2015); western South Atlantic ( Abramov 1992); Emperor Seamounts ( Chen 1980; Mundy 2005); Japan ( Machida 1985; Hayashi 2013), at 75–850 m depth.

Comparisons and Remarks. Epigonus denticulatus belongs to the E. pandinonis group ( Okamoto & Motomura 2013). This species is similar to E. elongatus in having a slender body and lacking a opercular spine ( Fig. 8 ); however, it differs from E. elongatus in having 28–34 gill rakers (22–23 in E. elongatus ) and a pair of ribs on the last abdominal vertebra (vs. absent on these ribs in E. elongatus ). Epigonus denticulatus is similar to E. marisrubri , also a member of the E. pandionis group in the Western Indian Ocean, but most of specimens of E. denticulatus have no tooth patch on the tongue (vs. tooth patch present in E. marisrubri ) and a short pectoral fin (not reaching level of the origin of second dorsal fin, 14.1–19.9% SL, vs. reaching level of the origin of second dorsal fin, 24.3–26.0% SL in E. marisrubri ). Furthermore, E. denticulatus can be distinguished from E. angustifrons , E. macrops , and E. telescopus in having 28–34 gill rakers (vs. 33–36 in E. angustifrons , 18–20 in E. macrops , and 23–26 in E. telescopus ) and in lacking an isolated dorsal fin spine between first dorsal and second dorsal fins (vs. present in E. angustifrons , E. macrops , and E. telescopus ). Epigonus exodon has a small number of pored lateral-line scales (35–37 vs. 45–49 in E. denticulatus ) and anteriorly projecting teeth on the symphysis of lower jaw (absent in E. denticulatus ). The remaining seven species of the genus in the Western Indian Ocean, E. bispinosus , E. idai , E. lenimen , E. marimonticolus , E. pectinifer , E. robustus , and E. waltersensis , are characterized by having a pungent opercular spine as members of the E. constanciae group (opercular spine absent in E. denticulatus ).

Figures

FIGURE 2. Distribution of three species of the Epigonus pandionis group in the Western Indian Ocean.

FIGURE 8. Epigonus denticulatus, SAIAB 193759, 120.0 mm SL.