Noell: Laival development of Hyporhamphus melanochir and H. regulans 



373 



Figure 3 



Larval and juvenile /fvpor/iomp/i us regularis. (A) 7.1-mm yolksac larva (L 3076-01 ). (B) 9.4-mm larva 

 (L 3076-02). (C) 12.3-mm larva (L 3076-03). (D) 15.5-mm larva (L 3076-04). (E) 24.7-mm juvenile (L 

 3077-01). Myomeres omitted in (D). 



4% BL at 13.1 mm and increases to a maximum of 24% BL 

 in the 31.5 mm juvenile. The first dorsal-fin ray is shghtly 

 posterior to or directly above the corresponding anal-fin 

 ray. Larvae have 51-54 vertebrae. Scales first appear be- 

 tween 18.1 and 24.7 mm laterally on the tail, anterior to 

 the caudal peduncle. 



Development of fins Completion of fin development in H. 

 regularis occurs in the following sequence: C — ► D — ► A — > 

 Pj, Pg (Table 4). Development of the caudal fin is incomplete 

 at birth; 6-1-7 principal rays are present in the 7.0-mm 

 yolksac larva, and the full complement (7-t-8) shortly after, 

 by 7.7 mm. Distinct anal-fin bases are visible at 7.0 mm. A 

 full complement of 14-17 dorsal and 15-19 anal-fin rays 

 is attained at 10.1 and 10.5 mm, respectively. The pectoral 

 base and finfold are present at birth, and incipient rays first 

 appear by 8.1 mm; all 11-12 rays are formed by 18.1 mm. 



The pelvic fin buds appear by 13. 1 mm, and all six pelvic-fin 

 rays are formed by 18.1 mm. 



Pigmentation Pigmentation of H. regularis larvae is 

 similar to that of H. melanochir larvae except along the 

 dorsal and ventral margins. Dorsal pigmentation consists 

 of 19-22 melanophore pairs in longitudinal rows between 

 the head and dorsal fin origin (Fig. 4A). A large pigment 

 blotch is present ventrally on the isthmus and anteriorly 

 on the gut. 



Discussion 



This study provides the first descriptions of larval develop- 

 ment of hemiramphids endemic to marine (H. melanochir) 

 and estuarine (//. regularis) waters of Australia. 



