STRUHSAKER: ARGYRIPNUS BROCKl NEW SPECIES 



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18 



16 



14 



12 



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40 



50 



60 



70 



80 



90 



STANDARD LENGTH (mm) 



Figure 2. — Distribution of VAV + anterior AC photophores by standard length for 60 

 specimens of Argyripnus brocki (X) and 47 specimens of /4. ephippiaius (dots). 



exhibits a significant regression coefficient {P 

 < 0.001) for this character, there is much varia- 

 tion (r- = 0.503) and considerable overlap with 

 the other two species. 



In addition to possessing diagnostically fewer 

 VAV + anterior AC photophores, posterior 

 photophores, gill rakers, and vertebrae, A. 

 brocki exhibits further differences in numerical 

 characters from the other three nominal species. 

 The range in pectoral-ray numbers (13-16) for 

 A. brocki although similar to A. ephippiatus 

 (14-16) only slightly overlaps that of A. irides- 

 cens (16-17) and is less than that of A. atlanti- 

 cus (17-19). The dorsal-ray counts are modally 

 11 for A. brocki and A. ephippiatus, while they 

 are 12 for A. iridescens. The rays of the first 

 anal fin of A. brocki (10-12) are fewer than for 

 A. iridescens (13-14) and A. atlanticus (13-15), 

 while they are modally one less than for A. 

 ephippiatus (11-13). The number of rays in the 

 second anal fin of A. brocki is modally one less 

 than those of A. ephippiatus. Accordingly, A. 

 brocki usually has one to two fewer total anal 

 rays than A. ephippiatus. 



Measuremeyits. — The original measurements 

 of the 20 specimens in the type series and their 

 range as percent of SL are given in Table 2. 



Linear regressions were calculated and values 

 for ^/-intercept, regression coefficient, and r- 

 are also presented. 



A. brocki does not differ greatly from the 

 other species in most of the other body propor- 

 tions not mentioned in the diagnosis. It does 

 exhibit a strong tendency to be more deeply 

 bodied than A. ephippiatus. Comparison with 

 A. iridescens is difficult because only larger 

 specimens are available for that species. The 

 adipose fins of Argyrip)ius spp. exhibit consid- 

 erable variation in the lengths of their bases 

 and distances between their origins and the 

 dorsal fins; much of this variation appears due 

 to mechanical damage. In some specimens the 

 adipose fin is completely missing. 



The length-frequency distribution for 123 

 specimens of A. brocki is given in Figure 3. 

 Females longer than 65-70 mm seem to be 

 mature. 



Color. — All three species examined have 

 the same basic pigmentation pattern. The patch 

 of black pigmentation on the upper portion of 

 the body just behind the head is very seldom 

 entire in specimens of A. brocki and A. ephip- 

 piatus because of chafing in the trawl, but it 

 still appears that this patch is best developed in 



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