McMillan: Three species of hagfish from tfie Galapagos Islands 



115 



specimen was possible because of the use of a min- 

 now trap with very small openings. Because of the 

 larger openings of the mjrxinid traps most often used, 

 hagiishes of less than 200 mm length are seldom 

 caught because they escape before a trap reaches the 

 surface. 



The larger specimen with normal pigmentation has 

 been designated as the holotype (in spite of its one 

 abnormal GP), because its adult size allowed deter- 

 mination of gender and multicusp pattern, as well 

 as more accurate measurements and slime pore 

 counts. These two specimens are assigned to the same 

 species because there is such close agreement in cusp 

 and slime pore counts and most body proportion and 

 because they were collected in the same JSL dive. A 

 difference of one gill pouch is common in large col- 

 lections of Eptatretus having nine or more GP, and 

 this difference may be found occasionally in species 

 having only five or six gill pouches. More specimens 

 will be required to determine the usual number of 

 GP, and whether there are enough other differences 

 to warrant separating into two different species. 



Discussion Three species of five- or six-gilled 

 Eptatretus from the Caribbean Sea are E. minor and 

 E. multidens Fernholm and Hubbs (1981), and E. 

 mendozai Hensley ( 1985). Although these three spe- 

 cies may have once shared a common ancestor with 

 E. grouseri, they are readily distinguished by their 

 unusual 3/3 multicusp pattern (three fused cusps on 

 both the anterior and posterior rows of cusps). The 

 3/2 multicusp pattern of E. grouseri commonly oc- 

 curs in most species of Eptatretus: two other five- 

 gilled species with this pattern are E. profundis 

 (Barnard, 1923) from South Africa and E. eos 

 Fernholm (1991) from the Tasman Sea, the latter a 

 distinctive pink color and possessing a tube-shaped, 

 elongated "snout." Both of these species have about 

 26 prebranchial slime pores, an unusually high num- 

 ber for Eptatretus and twice as many as found in E. 

 grouseri. Four species of Eptatretus with six gill 

 pouches and the 3/2 multicusp pattern are E. burgeri 

 (Girard, 1854) from Japan and Korea, E. hexatrema 

 Barnard (1923) from South Africa, E. longipinnis 

 Strahan (1975) from South Australia, and E. 

 chinensis Kuo and Mok (1994) from the South China 

 Sea. Eptatretus burgeri has a distinctive white mid- 

 dorsal line as well as notably higher prebranchial 

 and total slime pore counts, whereas the other three 

 species have prebranchial pore counts two to three 

 times that of E. grouseri. Although the number of 

 GP is the same, these six species are not considered 

 closely related to E. grouseri because of the signifi- 

 cant differences in prebranchial and total slime pore 

 counts, as well as wide geographic separation. 



Eptatretus mccoskeri new species 



Holotype CAS 86431, male, 320 mm TL, taken at 

 01°06.3'S, 89°06.9'W, in a minnow trap at 704 ft [215 

 m], 16 Nov 1995. 



Paratypes All males, taken with the holotype; 

 SI097-75, 2(283,300 mm TL); and USNM 344905, 

 298 mm TL. 



Diagnosis Eight gill pouches and apertures each side, 

 last GA confluent with the PCD on the left side; 12 

 multicusps (3 fused cusps in each row), unicusps 36— 

 39 (9,9 to 10,10 unicusps in each anterior and 9,9 to 

 9,10 in each posterior row), total cusps 48-51; total 

 slime pores 72-74, prebranchial 14-15, branchial 7, 

 trunk 40-42, tail 10-12. Ventral fmfold absent or 

 vestigial; caudal fmfold with white margin; head 

 slightly lighter than body color, face dark except for 

 small white area around mouth; barbels all white 

 (Fig. 2, D-G). 



Description Body color brownish black with head 

 region slightly lighter than body color, face dark ex- 

 cept for small white area around the mouth; eye spots 

 visible, but not prominent; face dark, in sharp con- 

 trast to completely white barbels; prominent white 

 margin around CFF; rostrum bluntly rounded, nearly 

 straight across; nasal orifice large, face wide with 

 the distance between the pairs of barbels about equal 

 to that of their length. First five (4-6) GP lie along 

 the dental muscle; branchial aorta branches at the 

 sixth or seventh GP; first GA high, series curving 

 downward to the PCD near the ventral midline; se- 

 ries of prebranchial slime pores starts far forward; 

 branchial pores are tiny and close to ventroposterior 

 margins of each GA, trunk pore series starts above 

 and behind the PCD, a space about 5-6 mm between 

 last trunk pore and origin of cloaca. Prebranchial 

 length is about one fourth of TL, trunk length about 

 half of TL; greatest body depth in the trunk region 

 about equal to the tail depth, both about 10 percent 

 of TL (Table 1). 



Etymology This species is dedicated to my friend 

 John E. McCosker, Senior Scientist, California Acad- 

 emy of Sciences, San Francisco, California, for pro- 

 viding this new study material, as well as for his 

 important contributions to marine biology. 



Distribution Known only from the Galapagos Is- 

 lands, Ecuador; all four specimens were taken in one 

 dive (JSL 3936) from a minnow trap set on sand bot- 

 tom at the top of a seamount southeast of Isla San 

 Cristobal (Chatham Island) at about 215 m, the shal- 



