240 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



Table 63. Characters of the Myctophidae. (0) = plesiomorphic 

 state, (1) = apomorphic state, (2) = different or advanced apomorphic 

 state, 1 = by outgroup comparison, 2 = raised photophore, 3 = gener- 

 alized larva, * = discussed in text. 



Characters 



1. Jaws long (0). moderate (1), short (2)—*. 



2. Extrascapulars 2 (0), 1 from fusion (1), 1 from loss (2) — *. 



3. Cleithral shelf absent (0), present (1)— 1. 



4. Pre 3-9 (0?), 1-2(1?)-*. 



5. Larval eyes round (0), narrow ( 1 )— 1 , 3. 



6. Dn present (0?), absent (1?)-*. 



7. Moderately or strongly hooked teeth in posterior dentary absent 

 (0), present (1)-1. 



8. Procurrent ventral rays 5-10 (0), 9-15 (1)-1. 



9. Supramaxillary present (0), absent (1)— 1, *. 



10. PO4 level (0), raised (l)-2. 



1 1 . Pubic plate narrow (0), wide ( 1 )— 1 . 



12. PO, and PO, level (0), raised (l)-2. 



13. VO, level (0), raised (l)-2. 



14. PVO horizontal (0). angled (1), vertical (2)-2. 



15. Caudal luminous organs present (0), absent (1)—*. 



16. AOa, level (0), raised (l)-2. 



17. Pol angled (0), horizontal (l)-2, *. 



18. Enlarged teeth in dentary absent (0), present (I)— I. 



19. Vertebrae 28-41 (0), 41-45, (1)-1, *. 



20. VO, level (0), elevated (1)- 2. 



2 1 . Enlarged dentigerous area on anterior premaxillary absent (0), pres- 

 ent (1)-1. 



22. Secondary photophores absent (0). present ( 1 )— 1 . 



23. Larval gut moderate (0), initially short (1), long (2) — 3, *. 



24. Larval trunk myoseptal pigment absent (0), present (1)— 1, 3. 



25. Slightly hooked teeth in posterior dentary absent (0), present ( 1 )— 

 I. 



26. Caudal luminous organs not sexually dimorphic (0), sexually di- 

 morphic (1)—*. 



27. Larval photophores (except Br,) absent (0), present (1)— 1, 3. *. 



28. Hyomandibular foramen behind anterior head (0), in anterior head 

 (1)-1. 



29. Accessory luminous tissue absent (0), present (1)— 1. 



30. Caudal luminous organs any other state (0), homogeneous and 

 translucent ( 1)—*. 



3 1 . Procurrent ventral rays without hooks (0), with hooks ( 1 )— 1 . 



32. Procurrent dorsal rays without hooks (0), with hooks (1)— 1. 



33. Crescent of white tissue on posterior iris absent (0), present (1) — 

 1. 



34. Pol 0(0), 1 (1), 2-3 (2)- 2, *. 



35. Dorsal process of opercular head of hyomandibula absent (0), pres- 

 ent (1)-1. 



36. SAOs weakly angled (0), strongly angled (I) — 2, *. 



37. Larval eyes moderate (0), very large (1)— I, 3. 



38. PLO level with PVO, (0), above PVO, (l)-2. 



39. SAO 2, close to VO and AO series (0), 2-3 above VO and AO 

 series (1)— 2. 



40. Larval pectoral fin moderate (0), large (1)— 3, *. 



41. Mouth terminal (0), subtcrminal (1)— 1. 



42. Antorbital broad (0), thin (1)— 1. 



43. Larval fin fold small (0), extensive (1)— 1, 3. 



44. PLO below (0) opposite or proximate to upper pectoral base (1), 

 far above upper pectoral base (2)— 2. 



45. Lower pharyngeal teeth conical (0), pegs or plates (1)— 1. 



46. Nasal trough-shaped (0), convex (1)— 1. 



47. Larval lower pectoral ray not elongate (0), elongate (1)— 1, 3. 



48. Gill rakers lathe-like (0), as tooth plates (1)— 1. 



49. Dorsal hypurals 4 (0), 3-2 (1). 1 (2)- I. 



50. Coracoid fenestra present (0), absent (1)— 1. 



51. Double row of isthmus pigment in larvae absent (0), present (1) — 

 1, 3. 



52. Premaxillary teeth conical (0), flattened (1)— 1. 



53. Larval pectoral base fan-shaped (0), wing shaped (1)— 1, 3. 



54. Larval head pigment present (0), absent (1)— 1, 3. 



Table 63. Continued. 



55. Larval choroid tissue absent (0). present (1)— 1, 



56. Larval body width moderate (0), thin (1)— 1, 3. 



57. Larval gut uniform (0), bipartite ( 1 )— 1 , 3. 



58. Ossified distal pectoral radials (0), 1-7 (1)— 1. 



59. CO, keel or ridge absent (0), present (1)— 1, *. 



group (the alepisauroids plus synodontoids) in his arrangement 

 of the order. We do not have further evidence to present in 

 favour of any of the above hypotheses (but do note the coiled 

 gut of neoscopelid lai-vae resembles the condition found in higher 

 groups). 



Generic Relationships 



Paxton (1972) analyzed features of the osteology and pho- 

 tophore patterns of the Myctophidae and presented a taxonomy 

 outlining his views of evolutionary relationships that included 

 two subfamilies (Myctophinae and Lampanyctinae), six tribes 

 (Myctophini, Gonichthyini, Notolychnini, Lampanyctini, Dia- 

 phini and Gymnoscopelini), 28 genera and two subgenera. The 

 Myctophinae was considered the more primitive of the subfam- 

 ilies, while the monotypic Notolychnini was provisionally placed 

 in the Lampanyctinae. In four papers Moser and Ahlstrom ( 1 970, 

 1972, 1974; Ahlstrom et al., 1976) detailed the larval charac- 

 teristics of all but two genera of Myctophidae and translated 

 their findings into a picture of evolutionary relationships. The 

 relationships proposed by Paxton and Moser and Ahlstrom were 

 strikingly similar overall and in many details. The larval studies 

 supported the recognition of two subfamilies composed of the 

 same genera indicated by the adult analysis, highlighted the 

 enigmatic features of Notolychnus. and recognized three addi- 

 tional tribes in the Lampanyctinae. Notable differences in the 

 conclusions of the two studies included consideration of the 

 Lampanyctinae as the most primitive subfamily by Moser and 

 Ahlstrom, non-recognition of the tribe Gonichthyini ( Tarleton- 

 beama. Loweina. Gonichthys, Ccntrohranchus) as a monophy- 

 letic taxon in the larval study, inclusion of the genera Taan- 

 ingichthys. Lampadena. Bolinchthys, Lepidophanes and 

 Ceratoscopelus in the tribe Gymnoscopelini by Moser and Ahl- 

 strom and the tribe Lampanyctini by Paxton, and recognition 

 of the genera Metelectrona and Parvilux as valid genera on the 

 basis of larval characters, which Paxton had synonymized with 

 Electrona and Lampanyctus respectively on the basis of adult 

 features. Neither study restricted characters to the derived state 

 and the proposed phylogenies were based on overall similarities. 

 The present work will attempt an analysis of derived character 

 states and re-examine the proposed relationships within the 

 family. 



We have used as character states (Table 63) features of adult 

 osteology and photophore patterns as described by Paxton (1972), 

 and features of larvae as described by Moser and Ahlstrom 

 (1970, 1972, 1974) and Ahlstrom et al. (1976) summarized in 

 Moser et al. (this volume). The distribution of the 

 character states among the genera (we have not considered sub- 

 genera in this analysis) is tabularized (Table 64). The criteria 

 for determining apomorphic character states have been consid- 

 ered by many, including Marx and Rabb (1972) and Zehren 

 (1979:153). We have used three criteria, the numbers of which 

 are listed after each character in Table 63: (1) Outgroup com- 



