OLNEY: LAMPRIFORMES 



379 



Fig. 20 1 . Photomicrograph of the posteriormost ponion of the ink 

 gland in young Lophotus lacepedei (HML 6851, 45 mm SL). Ink gland 

 is seen as the dark, tubular body overlymg the hindgut and vent. The 

 vent is indicated by an arrow. 



possess elongate anterior dorsal elements which are ornamented 

 with spatulate, pigmented swellings in some genera. As with 

 other fishes with ornamented larval appendages (Govoni et al., 

 1984), variation in ornamentation may be due to capture dam- 

 age. As a result, the absence of elaborate ornamentation in early 

 larvae of L. guttatus (Fig. 196), M. imdtiradiatus (Fig. 198) and 

 S. chordatus (Figs. 199 and 200) could be artifactual; (4) Pelvic 

 fin elements. Precocious appearance of ventral fin elements which 

 are stout, elongate and supported by well developed pelvic bones 

 is observed in all known lampriform larvae (Figs. 193, 195- 

 200). Variation among genera occurs in element number and 

 fate at metamorphosis. In I'elifer and Lampris, pelvic elements 

 are numerous and well developed in adults. In remaining genera, 

 reductive trends are evident and only regalecids retain strongly 

 developed and specialized pelvic fins (Oelschlager, 1978a); (5) 

 Minute spines on dorsal elements. Small, laterally projecting 

 spines are conspicuous in some young lampriform fishes and 

 have been reported in juveniles by Walters and Fitch (1960: 

 443), Rosenblatt and Butler ( 1 977:844), and Heemstra and Ken- 

 nemeyer (in press). In our material, these minute spines are 

 conspicuous in larval Zu. Trachiptenis. Regalecus. Lophotus 

 and Radiicephalus as well as juvenile specimens of Desmodema 

 and Eumecichthys. Larval Lampris. Metavelifer and Stylephonis 

 lack these characters; (6) Multiple pterygiophores interdigitate 

 in first two interneural spaces. In all our lampriform material, 

 only L. guttatus and M. multiradiatus have fewer than seven 

 pterygiophores which interdigitate in interneural spaces 1 and 

 2 (Table 100). In addition, only Lampris and Metavelifer (and 

 presumably Velifer) possess a single predorsal element. Inter- 

 digitation sequences in Velifer. Lophotus. Eumecichthys. Sty- 

 lephorus and Agrostichthys are unknown; and (7) Metamorpho- 



sis. The absence of abrupt ontogenetic transition delimits Lampris 

 (and presumably veliferids) from other lampriform genera. 



The distribution of ontogenetic characters 1-7 among lam- 

 priform genera may be instructive when considering suggestions 

 by previous authors of evolutionary trends within the order. 

 The indication of monophyly by Regan (1907, 1924) and the 

 adoption of this hypothesis by Greenwood et al. (1966) and 

 Oelschlager (1976a) is supported by the common possession of 

 characters 1-4 among all known lampriform larvae. Rigorous 

 testing of this hypothesis utilizing ontogenetic data, however, 

 must await a more complete knowledge of egg and larval de- 

 velopment among Lampriformes and between these fishes and 

 other groups. Rosen (1973) suggested that relationships among 

 trachichthyoids, berycids, zeoids and lampriforms seem plau- 

 sible. Ontogenic characters (1-4) which appear to unite the di- 

 verse lampriform genera are variously present, absent or un- 

 known in trachichthyoid, berycid and zeoid fishes and present 

 no clear picture of inter-relationships. Larvae of Diretmus and 

 Diretmoides (Post and Quero, 1981) lack these characters and 

 are distinguished by pronounced occipital and preopercular 

 spines. Polymixia sp. ( 1 0.0 mm SL; MCZ 58964) lack characters 

 2 and 3 (eggs of Polymixia are unknown) but possess well 

 developed ventral fins. These fins may not be present at hatch- 

 ing, however. Juvenile Cyttus traversi (James, 1976b) possess 

 elongate, ornamented and pigmented pelvic and anterior dorsal 

 elements, although the sequence of development of these struc- 

 tures is unknown. The rhomboidal body shape, symmetrical 

 caudal and jaw structure of C. traversi resemble deep-bodied 

 lampriform genera. 



Rosen and Patterson (1969), Rosen (1973) and Oelschlager 

 (1974, 1976a, 1978a, b, 1979) have examined osteological and 

 functional aspects of adult lampriform morphology and com- 

 mented on relationships. Recent fishes are represented by a 

 series of highly modified forms of which i'elifer is believed to 

 be the least specialized. Veliferids are considered to be more 

 closely related to Lampris than to any other genus on the basis 

 of similar body form, caudal morphology, meristics and the 

 possession of a predorsal element. No apomorphous character 

 serves as a criterion for monophyly in the Veliferidae (Oel- 

 schlager, 1976a). Ontogenetic characters 5-7, however, may be 

 useful in defining relationships between the two series of families 

 [Oelschlager's (1976a) Bathysomi and Taeniosomi] within the 

 order. 



Among the elongate genera, Agrostichthys is considered most 

 closely related to Regalecus (Oelschlager, 1978a, b). Desmo- 

 dema and Zu represent an apomorphous sister group of Tra- 

 chiptenis. considered the most primati ve trachipterid genus (Ro- 

 senblatt and Butler, 1977). Radiicephalus appears to be the least 

 specialized among all elongate lampriforms although it shares 

 several specialized features (ink sac, caudal filament) in common 

 with lophotids and Stylephorus (Harrison and Palmer, 1968). 



Virginia Institute of Marine Science, College of William 

 AND Mary, Gloucester Point, Virginia 23062. 



