539 



Abstract.-The endemic North Pacific 

 pleuronectid genus Lepidopsetta Gill 

 is revised to include three species: L. 

 hilineata (Ayres), L. polyxystra n. sp., 

 and L. mochigarei Snyder Adults of L. 

 biliiieata can be distinguished by a low 

 gill-raker count and high supraorbital 

 pore count; larvae may be distinguished 

 by four dorsal midline nielanophores, 

 heavy finfold pigment, a short snout- 

 to-anus length, and a deep body. The 

 species ranges from Baja California 

 to the eastern Aleutian Islands and 

 the extreme southeastern Bering Sea. 

 Adults of L. mochigarei are distin- 

 guished from all other members of 

 Lepidopsetta by higher scale and pre- 

 opercular pore counts and lower gill- 

 raker and supraorbital pore counts. 

 Larvae are similar to larvae of L. hilin- 

 eata but can be distinguished by their 

 postanal pigpnient pattern and melano- 

 phores on pectoral-fin rays. Lepidopsetta 

 mochigarei ranges from the southern 

 Sea of Okhotsk to Korea. Adults of L. 

 polyxystra n. sp. are diagnosed by a high 

 gill-raker count and low supraorbital 

 pore count; larvae are diagnosed by two 

 dorsal midline nielanophores, light fin- 

 fold pigment, long snout-to-anus length, 

 and a slender body. The species is found 

 from Puget Sound through the Bering 

 Sea and Aleutian Islands to the Kuril 

 Islands, overlapping with L. hilineata 

 from the extreme southeastern Bering 

 Sea to Puget Sound and with L. mochi- 

 garei in the southern Sea of Okhotsk. 

 Synonymies, diagnoses, descriptions, 

 and geographic distributions are pro- 

 vided for adults and larvae of all species; 

 keys are provided for adults. Descrip- 

 tions of early juveniles of eastern North 

 Pacific species are also presented. Under 

 the name of L. hilineata . L. polyxystra n. 

 sp. has been the subject of many studies 

 of eastern North Pacific Lepidopsetta . 

 All previous studies of specimens from 

 the southeastern Bering Sea into Puget 

 Sound should be considered applicable 

 at the generic level only, unless voucher 

 specimens are verifiable. 



Revision of the genus Lepidopsetta Gill, 1862 

 (Teleostei: Pleuronectidae) based on 

 larval and adult morphology, with a 

 description of a new species from the 

 North Pacific Ocean and Bering Sea 



James W. Orr 



Ann C. Matarese 



Resource Assessment and Conservation Engineering Division 



Alaska Fisheries Science Center 



National Marine Fisheries Service, NOAA 



7600 Sand Point Way NE 



Seattle, Washington 98115-0070 



E mail address ((or J W Orr) James Orr g'noaa gov 



Manuscript accepted 22 February 2000. 

 Fish. Bull. 98:539-582 (2000). 



The flatfishes (Pleuronectiformes) of the 

 eastern North Pacific Ocean constitute 

 a major component of the commercial 

 fisheries of the region. In the Bering 

 Sea, which encompasses the largest 

 fisheries resource of the United States, 

 the rock soles of the genus Lepidop- 

 setta are the second most abundant 

 flatfishes and the third most abundant 

 commercial groundfish species, second 

 only to yellowfin sole (Limanda aspera) 

 and walleye pollock (Theragra chalco- 

 gramma) (NMFS. 1999). 



At the species level, eastern North 

 Pacific pleuronectids have been con- 

 sidered well known. Nearly all species 

 were recognized and described during 

 the latter half of the 1800s. primarily 

 through the activities of California 

 ichthyologists. Among the names that 

 remain valid, the last species to be 

 described was Limanda sahkalinensis 

 Hubbs, 1915, although in the western 

 Pacific Microstomus shiintovi Borets, 

 1983, was most recently described from 

 the northwestern Hawaiian ridge. How- 

 ever, these earlier works were based 

 on adult morphology, and only recently 

 has a knowledge of the ontogeny of 

 these species been acquired. Among the 

 descriptions of early life history stages 

 of eastern North Pacific pleuronectids, 

 one morphological form could not be 

 traced to a recognized species. Exami- 

 nation of this form led to the following 

 revision of the genus Lepidopsetta. 



Four nominal species have been de- 

 scribed and allocated to the genus Lep- 



idopsetta: Platessa hilineata Ayres, 1855a, 

 was described from San Francisco mate- 

 rial, and apparently without the knowl- 

 edge of Ayres' slightly earlier description, 

 a specimen collected near Puget Sound 

 was described as Platichthys umbrosus 

 Girard, 1856. Gill (1862) erected Lepi- 

 dopsetta to contain Platichthys umbrosus 

 and later (1864) indicated that Platessa 

 hilineata Ayres, 1855a. was allied and 

 perhaps congeneric. Lockington (1879b) 

 published a redescription of L. umbrosa, 

 describing the misidentified new species 

 Isopsetta isolepis (Lockington, 1880a), 

 which he ultimately removed from Lep- 

 idopsetta to his new genus Isopsetta 

 (Lockington, 1883). In his description of 

 Lepidopsetta isolepis,he treated Platich- 

 thys umbrosus Girard as a synonym of 

 L. hilineata. Nearly 20 years after Gill's 

 erection of Lepidopsetta, Cope (1873) 

 described Pleuronectes perarcuatus from 

 Alaska, later considered a synonym 

 of L. hilineata by Jordan and Gilbert 

 (1881). Jordan and Evermann (1898) 

 considered each of these nominal species 

 members of Lepidopsetta and further 

 as synonyms of L. hilineata, although 

 they recognized the northern popula- 

 tions ("Puget Sound and northward") as 

 L. hilineata ujnbr-osa. Finally, Japanese 

 Lepidopsetta were described by Snyder 

 (1911) as L. mochigarei and Jordan and 

 Hubbs (1925) considered all Japanese 

 Lepidopsetta to be representatives of this 

 species. 



More recently, the genus has been en- 

 visioned as containing either two spe- 



