FAHAY AND MARKLE: GADIFORMES 



Table 76. Continued. 



281 



• Included in ventral count. 



iforms vaiies from occipital to slightly behind the pectoral fin- 

 tips and is long-based, reaching almost to the caudal fin (and 

 confluent with the caudal in Muraenolepis and Macruronus). 

 The anal fin originates close behind the anus (except in some 

 macrourids and steindachneriids) and also extends posteriorly 

 to near the caudal fin (confluent with caudal in Muraenolepis 

 and Macruronus). The caudal peduncle is, as a result, very short, 

 being longest in Merluccius. Variations are fijund in morids 

 (where the dorsal fin may extend farther posteriorly than the 

 anal, accommodating an asymmetrical caudal fin), and in Stetn- 

 dachneria and the Macrouridae (where the lack of a caudal fin 

 results in dorsal and anal rays tapering until they meet at the 

 tip of the tail). 



Gadiform dorsal and anal fin rays usually form after pelvic 

 fin rays begin (with the exception of the anterior dorsal ray in 

 Bregmaceros. which may form very early). Usually, the vertical 

 fins ossify together, so that caudal, dorsal and anal fin rays 

 appear at about the same time. In some genera with one long 

 dorsal fin (or a short first dorsal fin preceding a longer second 

 dorsal) fin rays in the longer fin form from two or more centers 

 of ossification, for example, Molva (Schmidt, 1906b) and Ater- 

 luccius (Ahlstrom and Counts, 1955). This may indicate either 

 preadaptation for the multiple dorsal/anal condition or second- 

 ary loss of multiple dorsals/anals. 



In cases where a long second dorsal fin is preceded by a rel- 

 atively short first dorsal fin, development of the first is usually 

 delayed and is often the site of the last fin ray formation, as 

 in Gaidropsarus {Gcmn. 1982) and tVop/jic/.v (Hildebrand and 

 "^able, 1938). In gadines, which have three dorsal fins, the first, 

 again, forms last. In Macrouridae and Merluccius. however, first 

 dorsal fin rays appear to form much sooner than the second 

 (Merrett, 1978; Ahlstrom and Counts, 1955). In the morids 

 Physiculus and Svetovidovia the first and second dorsal fins 

 develop together and divide late in development into apparent 

 first and second fins. Thus in the gadiforms, ossification of ver- 



tical fin rays is not uniformly anterior to posterior, or vice-versa, 

 or from the middle toward both ends, but instead is variable. 

 The relationship of dorsal and anal fin rays to centra is an 

 important characteristic in gadiforms (Rosen and Patterson, 

 1969; Marshall and Cohen, 1973). We believe the primitive 

 state, as exemplified by Muraenolepis, involved about three rays 

 per centrum. The major evolutionary trend, as identified by 

 Rosen and Patterson ( 1 969), is for this ratio to change anteriorly 

 where it is replaced by an approximate 2:1 relationship in most 

 families of gadiforms. In phycines, two derived character states 

 are found: a 7:1 relationship in rocklings (Cohen and Russo, 

 1979; Markle, 1982: fig. 5B) and a 2:1 relationship in hakes 

 (Markle, 1982: fig. 5C). 



Caudal fin. — Y>e^X>^\t its absence in over a third of all gadiforms, 

 the distinctive caudal skeleton has received an inordinate amount 

 of attention. In the present context it is doubly important, for 

 its presence offers identification as well as phylogenetic infor- 

 mation (Markle, 1982; Dunn and Vinter, 1984, MS). Tailed 

 gadiform larvae typically have a symmetrical fin where some 

 "secondary" rays form before some "primary." As used here, 

 "primary" refers to those rays articulating with the superior 

 hypural (hypurals three through five) while rays attached to 

 inferior hypurals (hypurals one and two), parahypurals, epurals, 

 accessory bones (the X and Y bones of some authors), or to 

 elongate neural and haemal spines are referred to as "second- 

 ary." Secondary rays also include those originating between 

 neural or haemal spines. 



We have summarized the distribution of gadiform caudal fin 

 rays in Table 76. Various authors lump secondary rays together 

 or express them as branched or unbranched. We have included 

 both methods, thus the sum of counts from different sources do 

 not always correspond. Several things are apparent from this 

 table. One involves the utility of using the distribution of caudal 

 rays both in intra- and intergeneric comparisons (Markle, 1982; 



