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ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



not evermannellids, Omosudis. or chlorophthalmids (Tuning, 

 1918; Rofen, 1966b; Johnson, 1982). It is presumed that pre- 

 cocious pectoral fin development in Rosenblattichthys is the 

 derived state. 



Peritoneal pigment sections (character #22). — For an overview 

 of the distribution of peritoneal pigment sections in inioms see 

 Johnson (1982) and the account of the Evermannellidae in the 

 present work. The single, transverse section seen in Rosenblatt- 

 ichthys. Scopelarchoides climax. S. signifer and presumably 5. 

 kreffti is here considered the primitive state. Loss of peritoneal 

 pigment in the larvae of Benthalbella is clearly apomorphous. 

 The single and paired conformation of the 3 sections in Sco- 

 pelarchoides nicholsi. S. danae and Scopelarchus is unique to 

 this lineage among inioms. The seemingly sequential progres- 

 sion of states 22 - 23 - 24 (Table 66: character 22) and the 

 correlation of these states with states 15-16-17 of character 

 16 strongly reinforce the concept of monophyly for this lineage. 



Larval pigment spots (character #23). — Deep-lying pigment spots 

 or areas occur widely among iniomous fishes (TSning, 1918; 

 Gibbs, 1959; Anderson et al., 1966; Rofen, 1966a; Moser and 

 Ahlstrom, 1970; Johnson, 1982) and their presence is here pre- 

 sumed to be primitive. As noted above, the position and relative 

 size of the spots differs between and is diagnostic of Scopelar- 

 choides (all 5 species) vs Rosenblattichthys. 



Transformation (character #24).— Larvae of Benthalbella are 

 unique among scopelarchids and possibly among inioms in 

 achieving very large size— 50 to 100 mm or more (varying by 

 species) while retaining a purely larval form and then exhibiting 

 a very "rapid" (based on size increment relative to total size) 

 transformation. This pattern is regarded as autapomorphous for 

 this genus. Larvae of two central- water species of Scopelarchus. 

 S. stephensi and S. michaelsarsi. exhibit a gradual transfor- 

 mation typical for most inioms, but, relative to other scopelar- 

 chids, exhibit onset and completion of transformation at sub- 

 stantially smaller sizes. This is regarded as an apomorphous 



feature linking these two species (as does the possibly redundant 

 character 5, reduction in number of vertebrae). 



Johnson ( 1 982:62-10 1 ) reviews some 49 characters seemingly 

 related to the question of sister-group relationship of the sco- 

 pelarchids and evermannellids. Found were derived states in 

 eight characters— multiple peritoneal pigment sections, lateral 

 attachment of dermosphenotic, restricted insertion of RAB (Ro- 

 sen, 1973) muscle, reduction in number of supraneurals, and 

 loss of the following: sclerotic bones, antorbital bones, tooth- 

 plate of second pharyngobranchial and basibranchial denti- 

 tion—characteristic of all alepisauroids (Alepisauridae, Ano- 

 topteridae, Evermannellidae, Omosudidae, Paralepididae) but 

 not the Scopelarchidae (at least primitively). Also found were 

 5 derived states characteristic of the Evermannellidae + Alep- 

 isauridae + Omosudidae but not the Scopelarchidae. viz. pos- 

 session of eight infraorbital bones, reduction in number of ep- 

 urals and loss of the following: body scales, lateral line scales, 

 suspensory pharyngobranchial. Admittedly many of the features 

 listed are "loss" characters and thus potentially worrisome, but 

 why should they uniformly be absent in the groups indicated 

 and not in the Scopelarchidae if their correlated loss is not 

 indicative of relationship? On the basis of the large number of 

 derived states shared among alepisauroids but not shared by 

 scopelarchids Johnson (1982) excludes the scopelarchids from 

 the alepisauroids and links them (tentatively) with chloroph- 

 thalmoids. Only a single derived state— gap in ossification 

 between first centrum and the skull— links the scopelarchids 

 with chlorophthalmoids, but this feature is found in no alepi- 

 sauroid. It should be reemphasized that the characters discussed 

 in Johnson (1982) were specifically chosen to explore the hy- 

 pothesis of sister-group relationship of evermannellids and sco- 

 pelarchids— a notion rejected. Many additional characters need 

 to be studied for any rigorous analysis of iniom relationships. 

 It is clear that the contribution of larval characters to this anal- 

 ysis will be great. 



Field Museum of Natural History, Roosevelt Road at 

 Lake Shore Drive, Chicago, Illinois 60605. 



Evermannellidae: Development and Relationships 

 R. K. Johnson 



THE Evermannellidae is one of five families included by 

 Johnson (1982, the most recent revision) in the primarily 

 oceanic Alepisauroidei. Excluded from this group are the Sco- 

 pelarchidae, long the supposed sister group of the evermannel- 

 lids, but tentatively allied by Johnson with the chlorophthal- 

 moids. All evermannellids are oceanic and mesopelagic, 

 occupying (as juveniles and adults) a wide vertical range in the 

 upper 1,000 m, and are not known to exhibit diel vertical mi- 

 gration. Evermannellids are relatively large-bodied (to 184.5 

 mm SL) predators, capable of engorging large food particles, 

 and concentrating most frequently on fish although Coccorella 

 may more frequently prey on squid. The family contains 7 species 



arranged in 3 genera. Evermannellids are distinguished among 

 other alepisauroids by the following combination of characters: 

 ( 1) an externally visible tripartite division of the tail musculature 

 with the epaxial and hypaxial muscles separated by a midlateral 

 band of muscle tissue, the lateralis superficialis; (2) lack of scales; 

 (3) greatly reduced, edentate basihyal; (4) restriction of gill teeth 

 to ceratobranchial of second arch; (5) presence of tubular or 

 semitubular eyes in 6 of 7 species; (6) lack of external keels on 

 body. The genera and species are distinguished by gross mor- 

 phological (eye, laterosensory pores, gut morphology, luminous 

 tissue), meristic, morphometric, osteological, pigment and lar- 

 val characters (Table 67). 



