FISHERY BULLETIN: VOL. 79, NO. 1 



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FIGURE?.— Larvae of A) Lep<oco«us armatus{8.1mmNL)andB)Cottus asper (8.2 ram SL) (A, B, Richardson and Washington 1980). 



develop three very small preopercular spines, 

 visible only on stained specimens, and the spines 

 of 14-15 mm G. ventralis are barely perceptible. 

 Gymnocanthus is relatively slender w^ith a semi- 

 pointed snout; it develops dorsal (at least G. 

 tricuspis), ventral, and lateral midline pigment. 

 Although it shares some characters with Myoxo- 

 cephalus, grouping the two does not seem war- 

 ranted. The spacing of the ventral series of 

 midline melanophores somewhat resembles the 

 situation in Myoxocephalus . General shape of 

 species of the two genera is also similar although 

 Myoxocephalus is much spinier. Some figures 

 indicate that Gymnocanthus has a preanal fin fold 

 as do at least some Myoxocephalus. 



Myoxocephalus (Figure 8) may have four to six 

 preopercular spines, two of which may be auxil- 

 i8U"y. Larvae are moderately slender with a semi- 

 pointed snout. Two distinct larval forms (subgen- 

 era?) occur in the genus. Those with dense lateral 

 pigment in the region posterior to the anus (M. 

 polyacanthocephalus , M. scorpius) and those with 

 only ventral midline pigment postanally (M. 

 aeneus, M. octodecemspinosus) . Another relative- 

 ly unpigmented species, M. quadricornis (marine 

 form), develops a lateral midline pigment series. 

 The spacing of the ventral midline melanophores 

 is similar in all species as is gut pigment. The fan- 

 shaped pectoral fin is obvious early in develop- 

 ment (at least in some species) and a preanal fin 



fold is present (in some or maybe all species). The 

 pattern of preopercular spination is unusual. All 

 species apparently have four principal spines but 

 some may have one or two posteriorly directed 

 auxiliary spines anterior to and near the base of 

 the second principal spine and/or an auxiliary 

 spine ventral and adjacent to the fourth principal 

 spine (Laroche^). Development of this unusual 

 pattern has not been adequately described for any 

 species of Myoxocephalus and needs closer exam- 

 ination. Auxiliary preopercular spines are un- 

 known in other genera except ?Malacocottus, 

 which has an anteriorly directed accessory spine 

 at the base of the second preopercular spine. 



Radulinus (Figure 9) is a heavily pigmented 

 form with four preopercular spines (never pro- 

 nounced), relatively pointed snout, slender body 

 (R. boleoides is deeper bodied than R. asprellus), 

 and long gut. It shares the characters of pointed 

 snout and slender body with Group 2 {Paricelinus 

 et al.) but differs too much (longer gut, heavier 

 pigmentation, reduced prominence of preoper- 

 cular spines) to be part of that group. It shares a 

 few similarities with the dark species of Myoxo- 

 cephalus, including a series of ventral midline 

 melanophores on the tail beyond the lateral pig- 

 ment (in larvae <8-9 mm NL) and a relatively 



•^J. L. Laroche, Research Assistant, Gulf Coast Research 

 Laboratory, East Beach Drive, Ocean Springs, MS 39564, pers. 

 commun. September 1978. 



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