WASHINGTON ET AL.: SCORPAENIFORMES 



447 



Myoxoccpha/us group includes 13 genera defined by the unique 

 larval character of a bony shelf on the anterior portion of the 

 preopercle. The Artedius group includes Clinocoiiiis. Oligocot- 

 liis. and Artedius Group A (see Washington, 1981). This group 

 is defined by six autapomorphic characters including three unique 

 larval features: 1) multiple preopercular spines; 2) enlargement 

 and expansion of the anterior neural arches; and, 3) first three 

 neural arches unfused. The Psychrolutes group includes Gilhert- 

 idia and Psychrolutes and is defined by six apomorphic char- 

 acters. Only one, the absence of head and preopercular spines, 

 is unique to the larval period. The Malacocottus group includes 

 Dasycottiis and Malacocottus and is defined by heavy, bony 

 arches on the cranium which form late in larval development. 

 Members of the last two groups were recently combined in the 

 family Psychrolutidae (Nelson, 1982) and correspond to his 

 subfamilies Psychrolutinae and Cottunculinae, respectively. The 

 Coitus group, including Cottus and Leptocottus. is defined by 

 four aulapomorphies, two of which are larval characteristics: 

 the first proximal dorsal pterygiophore is simple and slender in 

 contrast to all other cottid larvae and the parhypural is absent 

 in larvae of these genera. Further, larvae of these genera exhibit 

 a delay in ossification of the cranium and reduced head spi- 

 nation. 



The last two cottoid groups are: the Hemitripterus group in- 

 cluding the "cottids" Hemitripterus, Nautichthys. and Blepsias. 

 and the agonids. These share three derived characters: 1 ) mod- 

 ified prickle-scales; 2) a knobby fronto-parietal ridge; and, 3) 



broad plate-like epurals. The first two characters are unique 

 larval features of this group. 



These characters provide evidence that the Hemitripterus 

 group, traditionally placed in the Cottidae, may be the sister 

 group of the Agonidae. Several agonid genera, such as Hypsa- 

 gomts and Agonomelas are very similar to members of the 

 Hemitripterus group both as larvae and adults. In addition, 

 larvae of these genera share several apparently derived char- 

 acters. However, the agonids, including Hypsagonus and Ago- 

 nomalus share several autapomorphies unique to the agonids 

 mcluding one or two plate-like epurals, and extreme modifi- 

 cations of the pectoral girdle. 



The implications of these findings are that the agonids are 

 derived from the cottids and according to cladistic methodology 

 should be relegated to a sub-unit of the Cottidae. However, 

 Washington and Richardson (MS) do not propose any formal 

 changes in the cottids and agonids at this time. Larvae of only 

 about a third of the cottid genera have been studied. In addition, 

 the family or families of cottids have not been clearly defined 

 on the basis of derived characters, and until such time, we cannot 

 hope to fully understand the cottid-agonid interrelationships. 



(B.B.W., K.M.H.) Gulf Coast Research Laboratory, East 

 Beach Drive, Ocean Springs, Mississippi 39564; (W.N.E.) 

 Department of Ichthyology, California Academy of 

 Sciences, Golden Gate Park, San Francisco, Califor- 

 nia 94118. 



Tetraodontoidei: Development 

 J. M. Leis 



THE tetraodontoid fishes (Gymnodontes) are a diverse sub- 

 order of one large and three small families and about 150 

 recent species (Winterbottom, 1974a; Tyler, 1980). The four 

 families (Table 1 13) are largely tropical, but many species are 

 temperate. Most species are marine and bottom-associated in 

 shallow waters, but the Molidae is entirely pelagic and both the 

 Diodontidae and Tetraodontidae have fully pelagic species. The 

 Tetraodonlidae also includes a number of fully freshwater species. 

 Many tetraodontoids have a pelagic, often oceanic, juvenile 

 stage. 



Development 



Development of tetraodontoid fishes is not particularly well- 

 known. Previous reviews of the early development of the group 

 are by Breder and Clark (1947), Tortonese (1956) and Martin 

 and Drewry ( 1978). Early development of triodontids is entirely 

 unknown, and, overall, information is available for only 36 

 species. The information available for particular species of these 

 36 is often scanty. However, for the Molidae, information is 

 available for all three species. Complete (i.e., egg to juvenile) 

 information is available for about 10 species (Table 1 14). In the 

 following sections, I assume that the few taxa for which infor- 



mation is available are representative (these taxa and the de- 

 velopmental stages concerned are listed in Table 1 14). The fol- 

 lowing sections should be read in conjunction with Table 1 14; 

 citations listed in Table 114 are not repeated in the text. In 

 parentheses after the family heading I give the number of species 

 for which some information is available. 



On the basis of early life history characters, the tetraodontoid 

 fishes are a more coherent group than the balistoid fishes. 



Table 113. Merlstic Characters of Tetraodontoid Fishes 



Principally after Tyler (1980). N is the approximate number of 



recent species largely after Nelson (1976). Pelvic fins are lacking in this 



suborder. 



Family 



N 



C 



Vene- 

 brae 



Triodontidae 

 Tetraodontidae 

 Diodontidae 

 Molidae 



I 



130 



15 



3 



0-n, 1 1 



7-34 

 10-18 

 15-20 



10 



7-27 

 10-18 

 14-18 



15-16 

 12-20 

 18-25 



7-13 



12 

 II 



9-10 

 12-26* 



20 

 16-30 

 18-23 

 16-18 



* Not a true caudal fin. but a clavus or pseudocaudal. 



