Jordan and Bruce: Larval development of three roughy species 



83 



formed into a small ctenoid scale (Fig. 5A). Not all 

 scales develop spines at the same stage; by 10.2 mm, 

 scales have 1-3 spines (Fig. 5B). Three spines appear 

 to be present on all scales by 23.0 mm. A row of larger 

 spines appear on the ventral surface between the anus 

 and the pelvic fins by 7.2 mm and form the character- 

 istic ventral scutes of juveniles and adults by 15.0 mm. 



Pigmentation Pigmentation in preflexion Optivus lar- 

 vae is moderate and concentrated on the dorsal surface 

 of the gut, as well as the dorsal and ventral surfaces of 

 the trunk. Pigment is absent from the posteriormost 

 5-6 myomeres (including the notochord tip) as in 

 Paratrachichthys and Aulotrachichthys. During flexion, 

 the entire body and head become moderately pigmented 

 and the dorsal surface of the gut becomes heavily pig- 

 mented. The entire body and head is evenly pigmented 

 in the largest specimen (23.0mm, Fig 4E). The pelvic 

 fins are moderately pigmented by 4.7 mm; the pigment 

 contracts towards each base during flexion and disap- 

 pears by 23.0 mm. 



Discussion 



Considerable confusion exists in the systematics of 

 beryciform fishes at the species level. Current classifi- 

 cations are based almost entirely on adult characters. 



Keene & Tighe (1984) noted the usefulness of includ- 

 ing early-life-history characters in these studies, but 

 the lack of such data at that time for ten of the 

 beryciform families precluded an adequate appraisal. 

 The three genera featured here together share charac- 

 ters common to other described trachichthyid 

 larvae, including moderate to heavy pigment, a mod- 

 erate to large mouth, a stocky body form, precociously- 

 developing and heavily-pigmented pelvic fins, cranial 

 ridges, opercular spination, and a myomere count of 

 26-30. Pelvic-fin pigmentation is most pronounced in 

 Aulotrachichthys and Paratrachichthys and is least de- 

 veloped in Optivus. Dermal spination is well devel- 

 oped in Aulotrachichthys and Optivus, although ab- 

 sent in Paratrachichthys. Cranial ridges and opercular 

 spines are present in all of our series; however, 

 Aulotrachichthys develops by far the most pronounced 

 head spination of the three and perhaps of any re- 

 ported trachichthyid larva. 



Small trachichthyid larvae can be confused with zeids 

 and some gadoid larvae that also have precocious, 

 heavily-pigmented pelvic fins. However, zeid larvae are 

 more evenly pigmented, have pigment extending into 

 the finfolds in small larvae, generally have a higher 

 myomere count (29-42, Tighe & Keene 1984), and have 

 a more tightly coiled gut with consequently a longer 

 postanal length. The sequence in which fin-ray ele- 



