Abstract.— Seventy-two species 

 of hippolytid shrimp (Decapoda: Cnis- 

 tacea: Hippolytidae) have been re- 

 ported from the eastern Pacific (the 

 Aleutians to Cape Horn). There are 

 more species to the north of Magda- 

 lena Bay, Baja California, than in 

 tropical or temperate waters to the 

 south. Most species oi Euabis, Leb- 

 beus, Heptacarpus, and Spirontoca- 

 n's live along the temperate coasts 

 of North America; species of Thor, 

 Trachycaris, and Lysmata are most 

 common in warm-temperate to trop- 

 ical areas, and species of Hippolyte 

 range from cool to tropical regions. 

 In the eastern Pacific, species oiNau- 

 ticaris and Leontocaris have been 

 found only in the Southern Hemi- 

 sphere. An annotated key to the spe- 

 cies, with geogi-aphic and depth range 

 and selected synonyms, is provided. 



Key to the Hippolytid Slirimp 

 of the Eastern Pacific Ocean 



Mary K. Wicksten 



Department of Biology, Texas A&M University 

 College Station, Texas 77843-3258 



Manuscript accepted 22 March UntO. 

 Fishery Bulletin, U.S. 88:587-.598. 



Members of the family Hippolytidae 

 are among the most abundant and di- 

 verse carideans of the eastern Pacif- 

 ic. Hippolytids are eaten by birds and 

 fishes, and serve as cleaners for fishes 

 such as moray eels (Chace 1937, Lim- 

 baugh 1961, Hobson and Chess 1976, 

 Reynolds 1977). They are common in- 

 habitants of tidepools, kelp beds, sea- 

 gi-ass flats, and other nearshore areas, 

 but also range into the deeper parts 

 of the continental shelf and slope. 



The gi-eatest diversity of species of 

 hippolytids in the eastern Pacific is 

 in boreal to temperate waters of the 

 northern hemisphere (Table 1). Forty- 

 seven species live from the Aleutian 

 Islands to Baja California, Mexico. 

 Among these, Lebbeus vicinus has 

 the greatest range, from the Aleu- 

 tians to the Gulf of California. Hip- 

 polyte californiensis lives from the 

 coast of Alaska to the Gtilf of Califor- 

 nia. Eighteen other species range 

 from the Aleutians or the mainland 

 of Alaska south to southern Califor- 

 nia, USA, or Baja California, Mexico. 

 Twenty-one species range from the 

 Bering Sea or the Aleutians to Bri- 

 tish Columbia, Washington, or Ore- 

 gon. Two species have been reported 

 only from Puget Sound, and four 

 species range from the Bering Sea or 

 the Aleutians to northern or central 

 California. An additional six species 

 range from central California to Baja 

 California or the Gulf of California, 

 Mexico. 



In the Northern Hemisphere, spe- 

 cies of Spirontocaris, Heptacarpus, 

 Eualus, and Lebbeus are diverse. 

 Species of the first two genera are 

 not found in the Southern Hemi- 

 sphere, while species of the latter are 



more diverse in the northern than in 

 the southern hemispheres. Although 

 no species of these genera are found 

 off both North and South America, 

 Lebbeus washingtonianus and L. bi- 

 dentatns, and Eualus pusiolus and E. 

 dozei are very similar and may repre- 

 sent pairs of disjunct sibling species. 



Tropical areas of the eastern Pacif- 

 ic are poor in hippolytid species. Lys- 

 mata californica ranges from central 

 California to the Galapagos, while 

 Latreutes antiborealis ranges from 

 the Gulf of California to Chile. Thor 

 algicola and L. antiborealis are sib- 

 ling species of T. ynanningi and L. 

 pannilus of the Caribbean and warm- 

 temperate western Atlantic. Hippo- 

 lyte :ostericola, Trachycaris restric- 

 tus, and Lysmata intertnedia occur 

 both in the eastern Pacific and in the 

 Caribbean and tropical Atlantic. Thor 

 spinosus and Lysmata trisetacea 

 range from the eastern Pacific to the 

 Indo-West Pacific, and Thor ajnboi- 

 nensis is circumtropical. Only Hippo- 

 lyte williamsi, Heptacarpus yald- 

 wyni, and Lysmata galapagensis are 

 endemic and distinct. 



The hippolytid fauna of temperate 

 South America is depauperate com- 

 pared with that of North America. 

 Except for Leontocaris pacificus, the 

 only representative of this genus in 

 the eastern Pacific, all of the species 

 belong to genera present in tropical 

 or temperate areas of the northern 

 hemisphere. Four species oi Lebbeus 

 live on the continental slopes. 



Hippolytids of the eastern Pacific 

 inhabit a wide range of depths and 

 habitats. Species of Spirontocaris, 

 Lebbeus, and Eualus prefer habitats 

 from the lowest intertidal zone to the 



587 



