Larvae of Liparis fucensis and Liparis callyodon: Is 

 the "Cottoid Bubblemorp" Phylogenetically Significant? 



Jeffrey B. Marliave and Alex E. Peden 



ABSTRACT: Larvae of the slipskin snailfish, 

 Liparis fucensis, and of the spotted snailfish, 

 Liparis callyodon, are described; and fecundity/ 

 spawning information for these species is pro- 

 vided. Positive identification of larvae of both 

 species required that they be laboratory reared up 

 to identifiable juvenile stages. Too little taxo- 

 nomic information exists on larvae of this genus to 

 reveal diagnostic characters for northeast Pacific 

 species. The early development patterns of these 

 two species are contrasted; L. fucensis larvae grow 

 from a very small to a very large size during the 

 larval stage, and develop an enlarged subdermal 

 space, the "cottoid bubblemorph", whereas L. 

 callyodon larvae develop more typically. Evidence 

 from the literature indicates that this bubble mor- 

 phology is a convergent, derived character, and is 

 unsuitable for use in determining phylogenetic 

 relationships. 



Larval descriptions do not exist for any of the 17 

 species of the genus Liparis that occur in the 

 northeast Pacific Ocean (Matarese et al. in 

 press), except for illustrations of newly hatched 

 Liparis fucensis (Marliave 1975). Larvae of the 

 subfamily Liparidinae were discussed generally 

 by Able et al. (1984), with emphasis primarily on 

 pigment and ontogenetic schedule of develop- 

 mental landmarks. Able et al. (1984) included 

 an illustration (their figure 236 bottom) of an 

 unidentified cyclopterid from southern Cali- 

 fornia with an enlarged cranial and thoracic sub- 

 dermal space giving a bubble appearance, and 

 suggested that such a feature might be of tax- 

 onomic value. Another cottoid larva sharing this 

 bubble appearance is Malacocottus zonurus 

 (Washington et al. 1984). This type of anomalous 

 morphological feature of a larval fish must be 

 considered as a possible character for elucidating 

 phylogenetic relations (Kendall et al. 1984), and 

 the extent to which such a feature is conserva- 



Jeffrey B. Marliave, Vancouver Public Aquarium, P.O. Box 

 3232, Vancouver, B.C., Canada V6B 3X8. 

 Alex E. Peden, Aquatic Zoology Division, British Columbia 

 Provincial Museum, Victoria, B.C. Canada V8V 1X4. 



tive, as opposed to immediately adaptive, is fun- 

 damental to assessing the utility of such a 

 feature as a phylogenetic character (Cohen 

 1984). Thus, Haeckel's biogenetic law, that on- 

 togeny recapitulates phylogeny, becomes a moot 

 theory with developmental stages as intensely 

 subjected to selective pressures as the plank- 

 tonic larval stages of fish. This paper provides 

 insight regarding the presence (fucensis) versus 

 absence {callyodon) of the larval cottoid bubble- 

 morph in two closely related, sympatric Liparis 

 species. 



Adults of slipskin snailfish, L. fucensis, and 

 spotted snailfish, L. callyodon, look very similar 

 and are close in morphometries and meristics 

 (Clemens and Wilby 1961; Hart 1973). Liparis 

 fucensis is distributed over a greater depth 

 range than the shallow-water L. callyodon 

 (Clemens and Wilby 1961); but they do overlap in 

 shallow water. Spawning in L. fucensis involves 

 the male tending egg masses deposited among 

 polychaete worm tubes (Marliave 1975) or inside 

 empty mussel shells (DeMartini 1978) in shallow 

 subtidal waters. No information has been pub- 

 lished previously regarding reproduction of L. 

 callyodon. 



Two different approaches for obtaining larval 

 specimens — captive rearing and plankton tow- 

 ing — provided developmental series for these 

 two species. Both species were reared through 

 transformation to the juvenile stage, permitting 

 positive identification. This paper provides the 

 first larval descriptions for northeast Pacific 

 Liparis species. The bubble morphology of L. 

 fucensis larvae is constrasted with the more 

 typical larval morphology of L. callyodon. 



METHODS 



Eggs and a 67 mm ripe male of L. fucensis 

 were collected at a depth of 10 m from among the 

 tubes of Eudistylia polymorpha by divers in 

 Barkley Sound, British Columbia (lat. 48°50'N, 

 long. 125°08'30"W) on 26 May 1974. The embryos 

 were not visibly developed and the yolks were 



Manuscript Accepted April 1989. 

 Fishery Bulletin, U.S. 87: 735-743. 



735 



