Eptatretus grouseri, MCMILLAN, 1999

Mincarone, M. M., Plachetzki, D., McCORD, C. L., Winegard, T. M., Fernholm, B., Gonzalez, C. J. & Fudge, D. S., 2021, Review of the hagfishes (Myxinidae) from the Galapagos Islands, with descriptions of four new species and their phylogenetic relationships, Zoological Journal of the Linnean Society 192, pp. 453-474 : 461-462

EPTATRETUS GROUSERI MCMILLAN, 1999

GROUSER’ S HAGFISH

( FIGS 1, 2C; TABLES 1–3)

Eptatretus grouseri McMillan, 1999: 114 , fig. 2a [original description; type locality: Galapagos Islands, 00°14.6’S, 91°26.6’W, 2370 ft (722 m); type series: holotype, CAS 86428; paratype, SIO 97-77 (1)].

Eptatretus grouseri . – Mok et al., 2001: 1026. – Mincarone & McCosker, 2004: 164, figs 2, 3b. – Fernholm & Quattrini, 2008: 126. – McCosker & Rosenblatt, 2010: 172. – Knapp et al., 2011: 404. – Ruiz et al., 2011: 30. – Cruz-Mena & Angulo, 2015: 325. – Angulo & Del Moral-Flores, 2016: 103. – Mincarone, 2017: 802.

Eptatretus Eptatretus grouseri . – Møller & Jones, 2007: 63.

Material examined: CAS 86428, holotype (370 mm), NE Fernandina Island, Punta Espinosa , 00°14’36”S, 91°26’36”W, 722 m depth, submersible Johnson Sea Link , baited minnow trap, J. E. McCosker , R. G. Gilmore, 17 November 1995 . SIO 97-77 (ex CAS 86428), paratype, 1(138 mm), taken with holotype . CAS 201882 , 2 (315–420 mm), Seymour Island , 00°21’42”S, 90°15’00”W, 648 m depth, submersible Johnson Sea Link , baited minnow trap, C. Baldwin, J. E. McCosker, 25 July 1998 .

Diagnosis: Eptatretus grouseri differs from all congeners, except E. aceroi Polanco-Fernandez & Fernholm, 2014 from Colombia, E. profundus ( Barnard, 1923) from South Africa, E. wandoensis Song & Kim, 2020 from South Korea and E. wayuu Mok et al., 2001 from Colombia, by having five pairs (six pairs in one specimen of E. grouseri ) of gill apertures arranged in a straight line and a 3/2 multicusp pattern of teeth. Eptatretus grouseri differs from these fivegilled congeners by having: 44–48 total cusps (vs. 58 in E. aceroi , 40–43 in E. wandoensis and 41–43 in E. wayuu ); 11–12 prebranchial pores (vs. 44 in E. aceroi , 14–18 in E. wandoensis and 24 in E. wayuu ); 42–48 trunk pores (vs. 107 in E. aceroi , 48–51 in E. profundus and 38–40 in E. wayuu ); 13–15 tail pores (9–11 in E. wandoensis ); 71–79 total pores (vs. 174 in E. aceroi and 81–86 in E. profundus ) ( Mok et al., 2001; Polanco-Fernandez & Fernholm, 2014; Mincarone, 2017; Song & Kim, 2020).

Description: Body morphology, measurements and counts provided by McMillan (1999) and Mincarone & McCosker (2004).

Distribution and habitat: Galapagos Islands: known from four specimens collected in two localities: off Fernandina Island (Punta Espinosa), at 722 m depth, and off north-eastern Seymour Island, at 648 m depth ( Fig. 1).