LEIS: SYSTEMATICS AND ZOOGEOGRAPHY OK THE PORCUPINEFISHES 



Table l. — Fin ray counts of Djodon species. 



given for D. holocanthus were made on cleared and 

 stained material. 



The dermal spines require special terminology 

 and measurements, as given below. Measure- 

 ments, except for shaft length, were taken on dis- 

 sected spines (Figure 1). 



The spine shaft is that portion bearing the 

 pointed tip, but excluding the shaft extension. The 

 length of the spine (= shaft length) was taken 

 from the lower portion of the lateral arm to the tip 

 of the shaft. The starting point for this measure- 

 ment can be found most easily by probing around 

 the base of the spine. 



The shaft extension is the portion of the shaft 

 extending past the lateral arms of the base, and its 

 length was measured from the lower portion of the 

 lateral arm to the tip of the extension. 



The lateral arms of the base are the subdermal 

 portions of the spine upon which the spine pivots 

 during erection. The length of the spine base was 

 the straight line distance from tip to tip of the 

 lateral arms. 



The frontal spines are those of the anteriormost 

 row on the head between the eyes. The pectoral 

 axil spines are the spines immediately posterior to 

 the base of the pectoral fin. 



Figure l. — Typical Diodon body spine: (A) spine (or shaft) 

 length, (B) length of the shaft extension, (C) length of the spine 

 base. The tip of the spine shaft points caudad. 



The number of spines in a longitudinal row over 

 the dorsum from the snout to the dorsal fin base 

 (S-D spines) and the spines in a longitudinal row 

 over the ventrum from the lower jaw to the anus 

 (S-A spines) were counted. These rows of spines 

 are irregular and difficult to follow, so the counts 

 should be considered approximate. With practice, 

 repeated counts of ±1 can be achieved consis- 

 tently. The numbers of spines between pectoral 

 fins, both over the dorsum (P-D-P spines) and ven- 

 trum (P-V-P spines), were also counted, but these 

 counts are even less reproducible than the lon- 

 gitudinal counts. 



Repeated reference is made to the spines on the 

 caudal peduncle. In some species the only spines in 

 the region of the caudal peduncle are some rather 

 large spines associated with the dorsal and anal 

 fin bases. Although these spines extend over the 

 peduncle, their subdermal bases (lateral arms and 

 shaft extension) are at least partially anterior to a 

 line between the base of the posteriormost rays of 

 the dorsal and anal fins, and they are considered 

 not to be on the peduncle. In other species, there 

 are relatively small spines which are wholly pos- 

 terior to the line defined above on the dorsal and 

 dorsolateral surfaces of the peduncle; these spines 

 are considered to be on the peduncle (Figure 2). 



Larvae were obtained from plankton samples 

 (field specimens) and rearing experiments using 

 eggs from plankton tows (reared specimens). All 

 eggs and larvae were captured around the 

 Hawaiian island of Oahu. Rearing took place in 



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