Jordan and Bruce: Larval development of three roughy species 



79 



ent rays first appear above these bases by 5.4 mm. 

 Incipient rays appear in the pectoral fin shortly there- 

 after (5.5 mm). Ossification of dorsal, anal, pelvic, and 

 pectoral fins occurs during flexion, with full comple- 

 ments in all fins present by 7.8 mm. 



Spination Paratrachichthys larvae have only weakly 

 developed head spination. A low supraocular ridge is 

 present at 3.3 mm, developing 1-2 spines by 3.9 mm 

 (Fig. 2A). The number of supraocular spines increases 

 to 2-3 by 4.0 mm, reaching a maximum of 5-6 just 

 prior to flexion. During flexion, the supraocular spines 

 disappear. 



The single opercular spine is present by 6.9 mm and 

 is retained in the adult. Similarly, single preopercular 

 and posttemporal spines are present by 8.7mm and 

 are retained. Cranial ridges are present by 5.4 mm: 

 however, even by 10.0 mm these have not yet become 

 denticulate as they are in juveniles and adults. 



Pigmentation Paratrachichthys larvae are moderately 

 to heavily pigmented (with the exception of the last 

 2-8 myomeres, including the notochord tip) through- 

 out the entire larval period. Pigment tends to be con- 

 centrated over the dorsal and ventral surfaces of the 

 body and the dorsal surface of the gut. Otherwise, there 

 are few useful distinguishing features based on pat- 

 terns of pigmentation. 



The pelvic fins are heavily pigmented by 4.2 mm 

 and remain so in our largest postflexion larva 

 ( 10.0 mm). Some variation was introduced by the obvi- 

 ously faded pigment of certain specimens, the result 

 being a series of heavily-pigmented and a series of 

 moderately- to lightly-pigmented individuals. Because 

 the major pigment concentrations, morphology, and 

 meristic information were otherwise identical for the 

 two series, it is unlikely that variations in the inten- 

 sity of pigmentation indicate the presence of more than 

 one species. 



Scalation Juvenile and adult Paratrachichthys have 

 small, adherent, ctenoid scales covering the body and 

 a series of strong ventral scutes between the anus and 

 the anal fin (Woods & Sonoda 1973). Our largest larva 

 (10.0 mm ) has no sign of scalation and lacks the minute 

 dermal spines of other trachichthyid genera, although 

 a weak fleshy ridge develops along the ventral midline 

 between the anus and the anal fin by 7.6 mm, prob- 

 ably a precursor to the characteristic ventral scutes of 

 juveniles and adults. The 39.7 mm juvenile examined 

 was, in effect, a minature adult having completed 

 scalation, including the ventral scutes. 



Aulotrachichthys sp. (Fig. 3) 



Morphology Head length is about equal to body depth 

 at the pectoral fin until flexion, after which body depth 

 increases to 509c body length (Table 3). The mouth is 

 moderately large, reaching to the posterior margin of 

 the eye in our smallest specimen (2.8 mm), falling to 

 just short of the margin in our largest specimen 

 (7.9 mm). The body depth at the anus increases mark- 

 edly prior to flexion as the anus migrates anteriorly. 

 The gas bladder is inflated and prominent in all speci- 



