254 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



autapomorphies in three characters: unique pattern of juvenile 

 phase pigmentation 16 (19) and presence of vertically elongate 

 fossa at dentary symphysis 10 (12), presence of fully tubular 

 eye, 1 (2), unique to them among evermannellids, and show 

 further reduction in the number of lateral line segments 6 (8). 

 A single reductive character 14(17) also shared with Coccorella 

 links E. indica and E. ahlstromi and E. megalops. A final, ques- 

 tionable character 5 (6) links the latter two. In each case well- 

 defined autapomorphous features support the hypothesis of 

 monophyly of each genus and the information available appears 

 to adequately support most of the proposed scheme. 



Details concerning the contribution of two larval characters 

 to this analysis are discussed below. 



Peritoneal pigment ^frt/0/15. — Discrete peritoneal pigment sec- 

 tions are striking features of most aulopiform but not mycto- 

 phiform fishes (Johnson, 1974b, 1982; Okiyama, 1974b, this 

 volume). A single dorsomedial section characterizes the larvae 

 of all Aulopus (Okiyama, this volume), chlorophthalmoids and 

 (primitively) scopelarchids. Multiple (3 or more, serially ar- 

 ranged, paired or unpaired) sections occur in ipnopids (Bathy- 

 pterois), bathysaurids, synodontids, harpadontids, paralepidids, 

 Oinosudis and evermannellids. Peritoneal pigment sections are 

 paired, left and right, in synodontoids (sensu Johnson, 1982) 

 but single and connected dorsomedially over the gut in alepi- 

 sauroids. Peritoneal pigment sections are apparently lacking in 

 notosudids, some ipnopids, Alepisaurus, neoscopelids (perito- 

 neal pigment present but not in a discrete section, see Okiyama, 



this volume) and myctophids. Johnson (1982) concludes that a 

 single dorsomedial section is primitive for aulopiform fishes. 

 Three unpaired sections are found in larvae of Coccorella, Ev- 

 ermannella, Omosiidis and the paralepidine barracudina Par- 

 alepis atlantica (said by Rofen, 1966a:238, to be ". . . the most 

 primitive species in the Paralepididae."). Larvae of Odontosto- 

 niops norinalops exhibit 1 2 or more unpaired peritoneal pig- 

 ment sections, unique in the order, and a feature regarded as 

 autapomorphous. 



Juvenile phase pigmentation— ]o\\nson (1982) regarded fixa- 

 tion of the trilateral longitudinal pattern of juvenile phase pig- 

 mentation, as described above, as autapomorphous for the genus 

 Evermannella. 



It has long been supposed (Gregory and Conrad. 1936; Mar- 

 shall, 1955; Gosline et al., 1966) that the Scopelarchidae and 

 Everrriannellidae are closely related. This supposition was based 

 mainly on the occurrence of tubular eyes in both groups. John- 

 son (1982) argues against this notion, rejecting any close rela- 

 tionship of the Evermannellidae and Scopelarchidae, placing 

 the latter (tentatively) among the chlorophthalmoids, and plac- 

 ing the Evermannellidae as the sister group of the Omosudidae 

 plus Alepisauridae. The evidence for these conclusions is pre- 

 sented in Johnson ( 1 982) and briefly summarized in the account 

 of the Scopelarchidae in the present work. 



Field Museum of Natural History, Roosevelt Road at 

 Lake Shore Drive, Chicago, Illinois 60605. 



Myctophiformes: Relationships 

 M. Okjyama 



IN the traditional concept, the order Myctophiformes is con- 

 sidered to be a monophyletic assemblage with taxa having 

 much the same levels of organization, even though they have 

 undergone considerable adaptive radiation including some ex- 

 tremely specialized forms for particular habitats (Goody, 1969; 

 Marshall and Staiger, 1975; Johnson, 1982). 



Modem definition of the order including 16 families was first 

 established by Gosline et al. (1966). They recognized the fol- 

 lowing two suborders: 



Myctophoidei: Aulopidae, Synodontidae, Bathysauridae, 

 Harpadontidae, Bathypteroidae, Ipnopidae, Chlorophthal- 

 midae, Myctophidae and Neoscopelidae. 



Alepisauroidei: Notosudidae (=Scopelosauridae), Paralepidi- 

 dae, Omosudidae, Alepisauridae, Anotopteridae, Ever- 

 mannellidae and Scopelarchidae. 



This dichotomous system has been generally followed by re- 

 cent workers (Rosen and Patterson, 1969; Marshall and Staiger, 

 1975; Sulak, 1977), despite some minor changes or disagree- 

 ments in the definition of family limits. On the other hand, 

 Gosline (1971) proposed the idea of splitting the order into four 

 groups (!) without giving rigorous evidence. 



Rosen (1973) reevaluated the relationships among the Myc- 

 tophiformes and produced a very different provisional classi- 



fication based on a cladistic analysis of the group, where all of 

 the myctophiform fishes (except Myctophidae and Neoscopeli- 

 dae) form a monophyletic group, and likewise all the alepisau- 

 roid families (except Giganturidae) form a monophyletic assem- 

 blage. His phyletic hypothesis is radically different from those 

 of Gosline et al. (1966) and Johnson (1982). 



Notosudidae was later transferred from Alepisauroidei to 

 Myctophoidei (Bertelsen et al., 1976), and furthermore, Sco- 

 pelarchidae was removed from Alepisauroidei (sensu lato) in 

 the recent study of Johnson (1982) who further subdivided the 

 order into five possible major groups in three perceived lineages 

 (Fig. 131). 



Among these studies, Johnson (1982) is unique in carefully 

 evaluating larval characters such as the peritoneal pigment sec- 

 tions and the stomach pigmentation in juveniles, in considering 

 myctophiform phylogeny with special references to Scopelar- 

 chidae and Evermannellidae. 



As finely reviewed by Kendall ( 1 982), myctophiforms provide 

 an excellent example for elucidating systematic relationships 

 among fishes using larval characters, because larvae are known 

 for representatives of most of the families and in some cases 

 nearly all of the species within the families. Potential usefulness 

 of the larval groups in this connection has been well documented 

 for several families such as Myctophidae (Moser and Ahlstrom, 



