POTTHOFF and KELLEY: OSTKOLOCICAL DKVKLOPMKNT IN SWORDFISH 



Figure 2.— Capture localities (black dots) of larval and juve- 

 nile Xiphias glad i us used in this study. A locality may repre- 

 sent more than one capture. 



rays were still developing, 2 specimens differed 

 by two rays (1.3%) between sides, 63 differed by 

 one ray (40.9%), and 80 Xiphias (57.8%) had the 

 same count on both pectoral fins. Of 20 

 specimens 19.6-668 mm ESL, which had adult 

 counts, 10 differed by one ray between sides and 

 10 had the same count on both sides. 



The position of the pectoral fin in Xiph ias is on 

 the side of larvae but changes during growth to 

 ventrad in adults near the spot where the pelvic 

 fin is located in most Perciformes. Xiphias lacks 

 a pelvic fin and no vestiges of it were found 

 during development (Gregory and Conrad 1937; 

 Leim and Scott 1966; Ovchinnikov 1970; Yasuda 

 et al. 1978). 



PECTORAL FIN SUPPORTS 



Table 1. — Summary of fin development sequence in cleared 

 and stained larvae of Xiph tan gladius. PRC = principal 

 caudal rays, SCR = secondary caudal rays. 



Length ENL or ESL (mm) 



Fin 



First 



appearance 



of rays 



All 

 specimens 

 have rays 



Full 



complement 



of rays 



Number of rays 



in fully 

 developed fin 



Caudal 

 PCR 

 SCR 



Dorsal fin 

 Anal fin 

 Pectoral fin 



5.4 

 5.4 

 7.8 



5.5 

 5.3 

 4.8 



6.1 



6.1 



11.6 



6.1 



6.1 

 5.6 



26.7 



8.8-11.0 

 26.7 



8 1-13.9 



78-10.6 



14.2-196 



34-38 



17 



8-10 dorsal 

 8-11 ventral 



44-49 



16-19 



16-19 



ventral direction. Adult counts of 16-19 rays 

 were first obtained at 13.3 mm ESL and all 

 specimens >19.5 mm ESL had the adult count (N 

 = 20, X= 17.6, SD = 0.89) (Table 2). 



Pectoral fin ray counts differed for individual 

 specimens between sides. Of 154 specimens 4.6 

 mm ENL-19.5 mm ESL, in which the pectoral 



The pectoral rays were directly and indirectly 

 supported by the bones of the pectoral girdle and 

 its suspensorium. In fully developed juveniles 

 the girdle consisted on each side of a scapula and 

 a distal scapular radial (which supported the 

 dorsalmost ray directly and which orginated 

 from scapular cartilage), four large radials 

 (which supported the remainder of the rays 

 directly), a coracoid, and a cleithrum (Figs. 3-5). 

 The scapula was connected to the coracoid by 

 cartilage (Figs. 4, 5). The pectoral suspensorium 

 consisted of a posttemporal, a supracleithrum, 

 and a single postcleithrum. The posttemporal 

 and supracleithrum were connected from the 

 rear of the skull to the lateral side of the posterior 

 process of the cleithrum. The single post- 

 cleithrum extended over the abdominal area and 

 articulated on the medial side of the posterior 

 process of the cleithrum (Figs. 3-5). The pectoral 



Table 2.— Development of left pectoral fin rays for Xiphias gladius (3.7 mm ENL-225, 668 

 mm ESL). X = mean, SD = standard deviation. 



Length, mm 

 ENL or ESL 



Number of rays 



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 



SD 



3.6-4.5 



4.6-5.5 



5.6-6.5 



6.6-7.5 



7 6-8.5 



8.6-9.5 



9.6-10.5 



10.6-11.5 



11.6-12 5 



12.6-13.5 



13.6-14.5 



14.6-15.5 



15.6-16.5 



16.6-17 .5 



17.6-18.5 



18.6-195 



196-668 



7 

 20 



2 

 2 

 6 

 2 

 2 

 1 — — 



1 



1 



10 



1.6 



64 

 89 

 10.7 

 11.3 

 12.6 

 13.1 

 14.1 

 14.5 

 14.8 

 14.8 

 16.4 



165 

 16.3 

 17.6 



2.03 

 2 19 

 1.12 

 1.37 

 1.08 

 1.33 

 1.20 

 0.60 

 1.80 

 089 

 1.57 

 045 



1.20 

 208 

 089 



163 



