Abstract.— Developmental stages 

 of pygmy poacher, Odontopyxis 

 trispinosa, and blacktip poacher, 

 Xeneretmus latifrons, are described 

 and illustrated from specimens col- 

 lected from the northeastern Pacific 

 Ocean. External morphology, pig- 

 mentation, and meristic features are 

 described which distinguish larvae 

 of these species from other agonids 

 occurring in these waters. 



Postanal pigment patterns, par- 

 ticularly on the caudal finfold, dis- 

 tinguish preflexion larvae. Odon- 

 topyxis trispinosa larvae possess a 

 semicircular patch of melanophores 

 that covers nearly the entire caudal 

 finfold. The caudal finfold of pre- 

 flexion X. latifrons larvae are void 

 of pigment with the exception of a 

 small patch of melanophores near 

 the ventral margin of the notochord 

 tip. Flexion and postflexion larvae 

 can be distinguished by caudal and 

 anal fin pigmentation, head spina- 

 tion, and adult meristic features. 



Development of larval and early 

 juvenile pygmy poacher, 

 Odontopyxis trispinosa, and 

 blacktip poacher, Xeneretmus 

 latifrons (Scorpaeniformes: 

 Agonidae) 



Morgan S. Busby 



Resource Assessment and Conservation Engineering Division 



Alaska Fisheries Science Center 



National Marine Fisheries Service. NOAA 



7600 Sand Point Way NE, Seattle, Washington 98 I I 5-0070 



David A. Ambrose 



Southwest Fisheries Science Center 

 National Marine Fisheries Service, NOAA 

 PO. Box 271, La Jolla. California 92038 



Manuscript accepted 26 February 1993. 

 Fishery Bulletin, 91:397-413 ( 1993). 



The family Agonidae is a morphologi- 

 cally diverse group of relatively small, 

 benthic marine fishes. Agonids, com- 

 monly called poachers, are character- 

 ized by the presence of fused or over- 

 lapping bony plates that encase the 

 body. Fifteen genera represented by 

 25 species occur in the northeastern 

 Pacific (Matarese et al., 1989). 



The pygmy poacher Odontopyxis 

 trispinosa is a small (to 8.1cm SL) 

 subtidal agonid distinguished by an 

 elongate body, small vertical spine at 

 the snout tip, and a moderately de- 

 veloped occipital pit divided by a lon- 

 gitudinal ridge. Fin-element counts 

 of O. trispinosa are D III-VI, 5-7; A 

 5-7; P 13-15; V 1,2 (Matarese et al, 

 1989). The blacktip poacher Xener- 

 etmus latifrons is a larger (to 19cm 

 SL) subtidal agonid distinguished by 

 black margins on the dorsal fins and 

 a weakly developed occipital depres- 

 sion (Miller and Lea, 1972; Hart, 

 1973). Fin-element counts of X. 

 latifrons are D VI-VIII, 6-8; A 6-9; 

 P 13-15; V 1,2 (Matarese et al., 1989). 

 The presence of spiny scales on the 

 eyeballs distinguishes X. latifrons 

 from X. leiops. The absence of 



cheekplates distinguishes X latifrons 

 from X. triacanthus (Miller and Lea, 

 1972; Eschmeyer et al., 1983). 



Freeman (1951) hypothesized that 

 these two taxa are closely related 

 phylogenetically and placed them in 

 his subfamily Xeneretminae. The cla- 

 distic analysis of Kanayama (1991) 

 demonstrated close relationships be- 

 tween the two taxa which he placed 

 in the subfamily Anoplagoninae. 



The geographic range of adult 

 O. trispinosa extends from Southeast 

 Alaska to central Baja California. 

 Adult X. latifrons occur over a 

 slightly narrower range from Van- 

 couver Island to northern Baja Cali- 

 fornia (Eschmeyer et al., 1983). Both 

 taxa occur at depths of 18-370 m 

 (Miller and Lea, 1972; Hart, 1973). 

 Larval O. trispinosa and X. latifrons 

 are the most commonly occurring 

 agonids in the California Cooperative 

 Oceanic Fisheries Investigations 

 (CalCOFI) ichthyoplankton collection 1 . 



'Moser, H. G., ed. Guide to the early stages of 

 fishes from the California Current region. South- 

 west Fisheries Science Center, NMFS, P.O. Box 



271, La Jolla, CA 92038. In preparation. 



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