Abstract. Nine new species of 



hagfishes (Myxinidae, Myxine ) from the 

 Pacific and Atlantic coasts of North and 

 South America are described and a key 

 is offered to the new world hagfishes. 

 New data are presented for Myxine 

 circifrons from the eastern Pacific 

 Ocean, M. limosa from the northwest- 

 ern Atlantic Ocean, and M. affinis and 

 M. australis from in and near the Straits 

 of Magellan. Myxine limosa is removed 

 from the synonymy of M. glutinosa. The 

 nine new species occur as follows: M. 

 hubbsi along the Pacific coast from San 

 Francisco, California, to Valparaiso, 

 Chile; M. hubbsoides and M. pequenoi 

 near Valdivia, Chile; M. mccoskeri and 

 M. robinsi in the southern portion of 

 the Caribbean Sea; M. fernholmi, M. 

 knappi, and M. dorsum near the 

 Falkland Islands, and M. debueni in the 

 Straits of Magellan. Myxine mccoskeri 

 and M. pequenoi are regarded as 

 dwarfed, containing nearly mature eggs 

 or testes at total lengths of 230 and 175 

 mm, respectively. Hermaphroditism is 

 often found in individuals of M. hubbsi, 

 M. limosa, and M. affinis. 



Review of new world hagfishes of 

 the genus Myxine 

 (Agnatha, Myxinidae) with 

 descriptions of nine new species 



Robert L. Wisner 

 Charmion B. McMillan 



Marine Biology Research Division. 0202 

 University of California, San Diego 

 La Jolla, California 92093-0202 



Manuscript accepted 7 December 1994. 

 Fishery Bulletin 93:530-550 (1995). 



Hagfishes (slime eels) are cartilagi- 

 nous, eel-like, abundant bottom- 

 dwelling scavengers occurring at 

 depths ranging from a few to at 

 least 2,400 meters. Myxine is one of 

 the six recognized genera in the 

 "agnathan" family Myxinidae (Nel- 

 son, 1994). In the new world it com- 

 prises eight species in the Atlantic 

 Ocean and six in the Pacific (refer- 

 ences in this study); species occur- 

 ring in the Straits of Magellan also 

 may occur in either ocean. The ge- 

 nus Myxine, which presently con- 

 tains 19 species including those in 

 this study, is characterized princi- 

 pally by all the efferent gill pouch 

 ducts discharging into a single ap- 

 erture on each side, the left being 

 confluent with the pharyngocutan- 

 eous duct. This character is shared 

 by the genera Neomyxine Richard- 

 son, 1953, and Nemamyxine Richard- 

 son, 1958. Neomyxine is further char- 

 acterized by having paired lateral 

 finfolds in the prebranchial region, 

 as well as the usual ventral finfold 

 posterior to the gill apertures. In 

 Nemamyxine, the body is extremely 

 slender and the ventral finfold ex- 

 tends far forward nearly to the 

 anteriormost prebranchial slime 

 pores. In all other myxinids the ven- 

 tral finfold does not extend anterior 

 to the pharyngocutaneous duct. 

 Head grooves ("lateral lines" of ear- 

 lier authors) are lacking in genus 



Myxine as are the external eyespots 

 common in genus Eptatretus (McMil- 

 lan and Wisner, 1984). Hermaphro- 

 ditism does not occur in our mate- 

 rial of M. circifrons but is not un- 

 common in M. limosa, M. affinis, M. 

 australis, and M. hubbsi and occurs 

 in two of the three specimens of M. 

 hubbsoides. The remaining new 

 species have too few specimens to 

 state with certainty whether or not 

 hermaphroditism occurs among 

 them. Great variation in develop- 

 mental stages of eggs occurs among 

 specimens of the same length and 

 possibly age, which supports a 

 widely held belief that hagfishes 

 spawn throughout the year. As eggs 

 mature, the polar caps enlarge into 

 dome-like structures containing 

 anchor filaments that are connected 

 to the eggs when they are extruded. 

 With one exception (a female M. 

 limosa discussed below), eggs of all 

 specimens examined here were not 

 fully mature; polar caps were not vis- 

 ible, nor were they still encapsulated. 

 This study of new world hag- 

 fishes, the latest by us in a series 

 on the family Myxinidae begun by 

 Carl L. Hubbs (deceased), includes 

 all 14 known species of Myxine from 

 the Pacific and Atlantic coasts of 

 North and South America. We have 

 added old world M. glutinosa to all 

 tables for comparison with the closely 

 related M. limosa. Of the other four 



530 



