DUNN: DEVELOPMENT AND DISTRIBUTION OF LEUROGLOSSUS SCHMIDTI 



39-42 vertebrae, whereas L. schmidti possessed 

 49-51 vertebrae. Borodulina (1968) considered L. 

 schmidti to be a subspecies of L. stilbius, although 

 she suggested that L. schmidti might subse- 

 quently be recognized as a separate species, a 

 suggestion that she did not pursue because of 

 insufficient material. She also considered L. uro- 

 tranus (Bussing 1965), described from the Peru- 

 Chile Trench, to be another subspecies of L. stil- 

 bius. Ahlstrom (1968) noted the differences in 

 vertebral counts in L. stilbius and L. schmidti. 

 Subsequently Ahlstrom (1969) pointed out the 

 differences in egg size, pattern in migration of oil 

 globules during embryonic development, larval 

 pigment, and body proportions between L. stil- 

 bius and L. schmidti which, along with differ- 

 ences in vertebral counts, he felt, enabled recog- 

 nition of L. schmidti as a distinct species. 



Peden (1981) examined vertebral numbers in 

 Leuroglossus from samples collected from Mexi- 

 co to the Aleutian Islands and westward to Japan. 

 He noted that samples of Leuroglossus from Brit- 

 ish Columbia waters had an average of 8.5 more 

 vertebrae than those samples collected off Ore- 

 gon. He therefore recognized L. schmidti as 

 distinct from L. stilbius stilbius. As presently 

 known, the geographical ranges of the two spe- 

 cies do not overlap, as discussed below. Based on 

 the differences in vertebral counts in the two 

 nominal species reported by Borodulina (1968, 

 1969) and Peden (1981), the evidence presented 

 by Ahlstrom (1968, 1969), and the results of this 

 study, I consider L. schmidti specifically distinct 

 from L. stilbius. 



The valid name of the northern smoothtongue 

 is considered here to be L. schmidti, rather than 

 Therobromus callorhini or Leuroglossus callo- 

 rhini. Therobromus callorhini was described by 

 Lucas (in Jordan and Gilbert 1899) from bones 

 extracted from fur seal stomachs collected in the 

 Bering Sea. He noted that the specimens had 

 26 precaudal and 23 caudal vertebrae and placed 

 the species in Osmeridae. Chapman (1941) 

 showed that T. callorhini was notanosmerid and 

 later (Chapman 1943) he suggested that T. 

 callorhini (emended to callorhinus) was most 

 likely identical with either Bathylagus pacificus 

 or B. alascanus (= B. milleri). Cohen (1964) syn- 

 onymized Therobromus Lucas with Bathylagus 

 Gunther. Ahlstrom (1968, 1969) suggested that 

 the correct name of L. schmidti was Leuroglossus 

 callorhini, but did not formally propose such a 

 synonomy. 



If the two names do refer to the same species, 



then L. schmidti is a junior synonym of T. cal- 

 lorhini. The type material of Therobromus cal- 

 lorhini Lucas apparently no longer exists (ac- 

 cording to D. M. Cohen 7 ). However, as the name 

 T. callorhini has apparently not been used as a 

 senior synonym in more than 50 yr (Chapman 

 1943), T. callorhini constitutes a nomen oblitum 

 according to the International Code of Zoological 

 Nomenclature (Stoll et al. 1964). Hence, I con- 

 sider the valid name of the northern smooth- 

 tongue to be Leuroglossus schmidti. 



OCCURRENCE OF EGGS AND 



LARVAE OF 



LEUROGLOSSUS SCHMIDTI 



(Figure 5) 



Eggs and larvae of L. schmidti are broadly 

 distributed in near-coastal waters from about 

 southern Vancouver Island, British Columbia, to 

 the central Bering Sea. In midocean they are 

 apparently distributed as far south as lat. 46°N, 

 since eggs and larvae of L. schmidti were col- 

 lected in 1951 and 1955 from about lat. 46°-57°N 

 and long. 149°-179°W (Ahlstrom 1969; Moser 8 ). 

 They have apparently not been found in coastal 

 waters off Oregon, however, as the relatively few 

 specimens of Leuroglossus larvae, collected off 

 Oregon by Oregon State University, consisted 

 exclusively of L. stilbius stilbius (Richardson 

 1973; Washington 9 ). The results of an ichthyo- 

 plankton survey conducted in October-November 

 1971 from off Washington (lat. 46°45'N) to Dixon 

 Entrance, British Columbia (lat. 54°30'N), were 

 reported by Naplin et al. (footnote 4). Eggs of L. 

 schmidti were found only north of lat. 53°N off 

 Queen Charlotte Islands, whereas only L. stilbius 

 stilbius eggs were collected south of lat. 51°N off 

 Vancouver Island and coastal Washington. The 

 few Leuroglossus larvae collected during this 

 cruise were all L. schmidti, and they were taken 

 only north of lat. 54°N. Possibly the eggs identi- 

 fied as L. stilbius stilbius off Vancouver Island 



7 D. M. Cohen, National Systematics Laboratory. National 

 Marine Fisheries Service, National Museum of Natural His- 

 tory Washington, D.C. (present address: NWAFC, NMFS, 

 NOAA, 2725 Montlake Blvd. East, Seattle, WA 98112), pers. 

 commun. July 1980. 



8 H. G. Moser, Southwest Fisheries Center La Jolla Labora- 

 tory, National Marine Fisheries Service, NOAA, La Jolla, CA 

 92038, pers. commun. March 1980. 



9 B. B. Washington, School of Oceanography, Oregon State 

 University, Corvallis, Oreg. (present address: Gulf Coast Re- 

 search Laboratory, Ocean Springs, MI 39564), pers. commun. 

 November 1980. 



37 



