JOHNSON: SCOPELARCHIDAE 



249 



-26 



- 3 



—25 



— 24 



— 17 



— 11 

 8 



— 2 



— 14 

 9 



- 8 



23 



—18 

 —16 



-22 

 -15 

 -12 



- 9 



- 6 



-20 

 -19 



-27 

 -25 

 -21 



- 5 



Fig. 128. Proposed relationships among scopelarchid species based on adult and larval characters. Integers indicate derived character states, 

 listed in Table 66, possessed by taxa above indicated point in dendrogram. 



S. kreffti are unknown. I would argue that the specializations 

 oi Benthalhella, especially in larval characters relating to a unique, 

 rapid pattern of transformation preclude addition of 5. signifer, 

 S. climax, and presumably 5. kreffti to Benthalhella. But with 

 S. climax and S. kreffti very poorly known and with the only 

 "character" uniting this "group" of three being that they are 

 "left over," I remain with my 1974b (p. 217) compromise. 

 Uniting all 5 species of "Scopelarchoides" and diagnostically 

 separating them from Scopelarchus and Benthalhella are de- 

 velopment and conformation of accessory pigment spots char- 

 acter 23, and lateral appearance of the pelvic fin bud. character 

 21. It is possible that the state exhibited by Scopelarchoides 

 larvae is primitive in both cases (I doubt that lateral appearance 

 of the pelvic fin buds is primitive) but until this can be shown 

 through adequate outgroup comparison and until S. climax and 

 S. kreffti are better known, I refram from attempting the de- 

 scription of an additional genus. Thus, for now, the possibly 

 paraphyletic genus "Scopelarchoides" is retained. 



A summary of the contribution of 6 ontogenetic characters 

 to this analysis is presented below. 



Dermal pigmentation (character #/7j. — Dermal pigmentation 

 and/or dermal pigment stripes are found in all scopelarchid 

 genera except Benthalhella. however, the fixation of such pig- 

 ment into subequal stripes above and below the lateral line is 

 diagnostic of and unique to the four species of Scopelarchus. 

 This fixation is regarded as autapomorphous for this genus. 



.Adipose fin (character #18).— Scopelarchoides danae shares with 

 Scopelarchus an early reabsorption of most of the adipose (fin, 

 resulting in restriction to essentially adult proportions of the 

 base of this fin in specimens 20-22 mm SL. In other Scopelar- 

 choides as in Benthalhella and Rosenhlattichthys the adipose fin 

 remains elongate, to over the anterior anal fin rays, throughout 

 transformation, assuming adult proportions in specimens >30 

 mm SL. In combination with other characters uniting .S. danae 

 with Scopelarchus (Fig. 128) fixation of early restriction of the 

 dorsal adipose base is regarded as apomorphous for this group. 



Head length (character #19}. — The head in larval Rosenhlatt- 

 ichthys is unusually large, deep and massive, the head length 

 exceeding 30% of the SL. The head length in other scopelarchid 

 larvae does not exceed 30% of the SL and this is apparently the 

 caseinchlorophthalmoids(Taning, 1918;Okiyama, 1972, 1974b, 

 1981) and most alepisauroids (Rofen, 1966a: Johnson, 1982). 

 Larvae of Omosudis and .Alepisaiirus do exhibit exceptionally 

 large heads (Rofen, 1966b). The fixation of this character in 

 Rosenhlattichthys alone among scopelarchids is presumed to be 

 apomorphous. 



Pectoral fin development (character #20). — The order of fin ray 

 differentiation varies within and between iniomous families. 

 Precocious pectoral fin development is unique to Rosenhlattich- 

 thys among scopelarchids. It is also found in ipnopids (Okiyama, 

 1972, 1981) and myctophids (Moser and Ahlstrom, 1970) but 



