PIETSCH: OSTEOLOGY AND RELATIONSHIPS OF TETRABRACHIUM 



cialized [relative to antennariids and lophiids] 

 and in fact seems to give several clues to the origin 

 of the entire order." On the contrary, all evidence 

 indicates that a membranous connection between 

 the dorsal fin spines is apomorphic for angler- 

 fishes; of the approximately 255 living species of 

 the order this feature is present in the four 

 nominal species of Brachionichthys and in two 

 of the most derived species of the genus Anten- 

 narius (A. pauciradiatus and A. randalli; Pietsch 

 in prep.). Besides this character, Brachionichthys 

 possesses a set of autapomorphic features that 

 clearly remove it from consideration as "the most 

 primitive lophiiform." In addition to those autapo- 

 morphies listed in the analytical key below, 

 Winterbottom (1974:284) has identified an appar- 

 ently unique derived condition of the inclinator 

 dorsales muscle of the second dorsal fin spine 

 of Brachionichthys. 



Although strikingly dissimilar at first glance, a 

 number of synapomorphies support a hypothesis 

 of sister-group relationship between the families 

 Chaunacidae and Ogcocephalidae (Figure 41): 



7) Posteriormost branchiostegal ray exception- 

 ally large (in batrachoidids and all other 

 lophiiforms examined the size of the poste- 

 riormost branchiostegal does not differ sig- 

 nificantly from the adjacent branchiostegal); 



8) Gill teeth tiny, arranged in a tight cluster at 

 apex of pedicellike tooth plates (in batra- 

 choidids and other lophiiforms examined the 

 gill teeth are relatively large, and either 

 single, or associated with a flat, rounded 

 tooth plate); 



9) Gill filaments of gill arch I absent (in batra- 

 choidids and all other lophiiforms examined 

 gill filaments are present on arch I); 



10) Illicial bone, when retracted, lying within an 

 illicial cavity (an illicial cavity is absent in all 

 other lophiiforms examined; this character 

 does not extend to batrachoidids). 



Historically, chaunacids and ogcocephalids 

 have been classified with antennariids and brach- 

 ionichthyids by aspects of general similarity (i.e., 

 they neither look like lophioids or ceratioids). 

 Nearly all of these similarities are easily identi- 

 fied as character states that are plesiomorphic for 

 antennarioids (or for lophiiforms as a whole); the 

 synapomorphic nature of the few remaining simi- 

 larities is unresolvable. Thus, despite a thorough 

 osteological search, this study has failed to iden- 



tify the sister group of a group including the 

 Chaunacidae and Ogcocephalidae among the 

 known members of the Lophiiformes. In the ab- 

 sence of any evidence for or against, these taxa are 

 tentatively retained within the Antennarioidei 

 (Figure 41). 



Of the possible cladograms that could be con- 

 structed on the basis of the data provided in 

 this study, the one shown in Figure 41 involves 

 the least number of convergences. The preferred 

 phylogeny requires four cases of convergence 

 (Table 2), all of which, however, are loss charac- 

 ters that extend to other lophiiform taxa: 



1) the independent loss of palatine teeth in 

 the Tetrabrachiidae and Brachionichthyidae 

 [also absent in some ogcocephalids (see Brad- 

 bury 1967:409) and in all ceratioids]; 



2) the independent loss of a pseudobranch in 

 the Tetrabrachiidae, Lophichthyidae, and 

 Brachionichthyidae (also absent in chauna- 

 cids, ogcocephalids, and all ceratioids); 



3) the independent loss of the swim bladder 

 in the Tetrabrachiidae, Lophichthyidae, and 

 Brachionichthyidae (also absent in lophioids, 

 chaunacids, ogcocephalids, and ceratioids); 



4) the independent loss of the epural in the 

 Tetrabrachiidae and Brachionichthyidae also 

 absent in all antennariid genera examined 

 except A ntennarius , Antennatus , and Histrio; 

 [although present in the Caulophrynidae 

 (Pietsch 1979, fig. 11), the epural is absent in 

 all other ceratioids]. 



Plesiomorphic and autapomorphic features of 

 the major subgroups of the Antennarioidei are 

 incorporated into the following analytical key: 



lA. Spinous dorsal of three spines, emerging 

 from dorsal surface of cranium, illicium 

 not retractable within an illicial cavity; 

 ectopterygoid present or absent, inter- 

 opercle flat and broad 2 



IB. Spinous dorsal of one spine (spines II and 

 III reduced and embedded beneath skin of 

 head or lost), illicium retractable within 

 an illicial cavity; ectopterygoid present, 

 crescent shaped; interopercle elongate 

 and narrow 5 



2A. Parietals well separated by supra- 

 occipital; ectopterygoid triradiate; cer- 

 atobranchials I through IV toothless; 

 hypobranchials II and III bifurcated prox- 



415 



