FISHERY BULLETIN: VOL. 70, NO. 3 



round eyes. That these are phylogenetically na- 

 tural groups is supported by Paxton (1968, 

 1972) who, on the basis of adult osteology and 

 photophore arrangement, formally established 

 the same two groups of genera as subfamilies. 

 He grouped the 11 genera with narrow-eyed 

 larvae into the subfamily Myctophinae and the 

 17 genera with round-eyed larvae into the sub- 

 family Lampanyctinae. Further, in our paper 

 we described the evolutionary lineages within the 

 Myctophinae as evidenced by the structure of the 

 larvae. Many of our conclusions agreed with 

 those of Paxton (1968) , derived from adult char- 

 acters, but we differed ultimately with his dis- 

 tribution of the 11 myctophine genera into two 

 tribes and with his derivation of the subfamily 

 Lampanyctinae from an already highly evolved 

 lineage of the subfamily Myctophinae. The lar- 

 vae of the subfamily Lampanyctinae, although 

 morphologically conservative compared with 

 those of the Myctophinae, are useful, nonetheless, 

 in revealing evolutionary lineages within the sub- 

 family. The diversity of eye shape, so spectac- 

 ular in the Myctophinae, is absent in the Lam- 

 panyctinae, but the eyes of many genera are 

 distinctive because of their size, subtle but char- 

 acteristic deviation from the basic rounded out- 

 line, or presence of a ventral crescent of choroid 

 tissue. Likewise each genus of Lampanyctinae 

 has a characteristic body shape, although the 

 subfamily lacks the diversity of body form, so 

 dramatic in the Myctophinae. The peculiar mod- 

 ifications of the paired fins, common among the 

 larvae of Myctophinae, are generally absent in 

 the Lampanyctinae; only in the lampanyctine 

 genera Lampanyctus and Lobianchia do the pec- 

 toral fins attain some degree of specialization. 

 Three characters that are shared by the larvae 

 of many lampanyctine genera are: 1) the se- 

 quential development of three or more pairs of 

 early-forming photophores, 2) the development 

 of a series of melanophores at the dorsal and at 

 the ventral margins of the body, particularly in 

 the tail region, and 3) the development of one 

 or more melanophores above the brain. The se- 

 quence of development of early-forming photo- 

 phores is an especially useful character that may 

 provide a key to the elucidation of phylogenetic 

 lineages within the Lampanyctinae. Eleven of 



the 17 genera of Lampanyctinae develop such 

 early-forming photophores and can be grouped 

 as follows: 



Group A — Br2, PO5, and Vn form in that se- 

 quence; fourth pair, either PLO 

 or VLO, form later in larval period. 

 Scopelopsis - VLO fourth pair to form. 

 Notoscopelus - PLO fourth pair to form. 

 Lampichthys - PLO fourth pair to form. 

 Group B— Br2, Vn, PLO, and PO5 form sequen- 

 tially; photophores very small. 

 Ceratoscopelus - all four pairs formed early 



in larval period. 

 Bolinichthys - some species develop larval 

 photophores, as above, and others develop 

 only the Br2 as larvae. 

 Lepidophanes - Vn, PLO, and PO5 form al- 

 most simultaneously after the Br2; OPi, 

 and OPo form just before transformation. 

 Group C — Br2, PLO, and PO5 early-forming. 

 Lampadena - Br2, PLO, and PO5 appear se- 

 quentially; later in larval period, POi and 

 Vn form sequentially. 

 Lampanyctodes - Br2, PLO, and PO5 formed 

 on 9.2-mm larva; smaller larvae and, con- 

 sequently, information on sequence of 

 appearance, not available. 

 Group D— Br2, PO5, and POi early-forming. 

 Gymnoscopehis - Bn, PO5, and POi form se- 

 quentially, early in the larval period; 

 much later, the VOi and then PO2 appear. 

 Diaphus - two species groups; D. theta and 

 relatives form Br2, PO.5, PO,, VOi, PO2, 

 OP2, VO5, PO.3, PO4, VLO sequentially; 

 D. pacificus and relatives form Br2, PO5, 

 PO,, PO2, PVO,, P0.3, VOi, sequentially; 

 photophores added gradually in Diaphus 

 larvae with transformation at small size, 

 Lobianchia - Br2, POi, PO5, PVOi, PVO2 

 form sequentially. 

 The above groupings suggest phylogenetic af- 

 finities which, in most cases, are supported by 

 other characters of the larvae and adults. The 

 sequential development of the Br2, PO5, and Vn 

 photophores is unique to the genera of Group A 

 (Scopelopsis, Lampichthys, Notoscopelus) . The 

 arrangement of primary photophores, so conspic- 

 uous in the transforming specimens of Scopelop- 

 sis, affirms the close relationship of this genus 



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