MATARKSK anil MARLIAVE: LARVAL DEVELOPMENT OK ROSYLIP SCULPIN 



superior hypural and 7 are supported by the in- 

 ferior hypural). Ahlstrom 5 generalized that all 

 members of the family Cottidae probably have a 

 total of 12 principal caudal rays, 6 supported by 

 the superior hypural and 6 supported by the in- 

 ferior hypural. Verification of this principal fin 

 ray count came from counts on 20 adult speci- 

 mens acquired for this study, 19 of which actu- 

 ally had a 6+7 count. Richardson 6 has also ob- 

 served a number of exceptions to a 6+6 count in 

 other members of the family Cottidae. 



A symmetrical fin fold surrounds the tip of the 

 notochord in newly hatched specimens 6.0 mm 

 SL. In 7.2 mm SL larvae, a thickening is visible 

 ventral to the notochord (Fig. 2A). By 8.5 mm SL, 

 the ventral thickening is differentiated into 

 three cartilaginous plates (Fig. 2B). The anterior 

 plate represents hypural 1 (parhypural ) followed 

 by a larger plate presumably representing the 

 fusion of hypurals 2 and 3. Posterior to hypurals 

 2 and 3, a third plate represents hypural 4. A few 

 caudal fin rays are also visible by 8.5 mm SL. In 

 slightly larger larvae of 8.7 mm SL the urostyle 

 is just beginning to undergo notochord flexion, 

 and the unossified hypural 1 has fused with hy- 

 purals 2 and 3 forming the inferior hypural plate 

 (Fig. 2C). Also in 8.7 mm SL larvae, differentia- 

 tion of hypural 5, and epurals 1 and 2 is visible 

 (Fig. 2C). In larvae undergoing notochord flex- 

 ion (10.0 mm SL) unossified hypurals 4 and 5 

 have begun fusing to form the superior hypural 

 plate (Fig. 2D). We did not detect fusion of a sixth 

 hypural bone during the formation of the super- 

 ior hypural plate. If a sixth hypural bone de- 

 velops late in the larval period as it does in the 

 phylogenetically related blackgill rockfish, Se- 

 bastes melanostomus, (Moser and Ahlstrom 1978), 

 it was not evident in the juveniles or adults we 

 examined. The first appearance of unossifed 

 epural 3 also occurs in specimens about 10.0 mm 

 SL (Fig. 2D). Ossification proceeds rapidly once 

 the larvae have undergone notochord flexion. By 



5 E. H. Ahlstrom, Southwest Fisheries Center, National Ma- 

 rine Fisheries Service, NOAA, La Jolla, CA 92038, pers. com- 

 mun., class notes, 1971. (Deceased.) 



6 S. L. Richardson, Gulf Coast Research Laboratory, East 

 Beach Drive, Ocean Springs, MS 39564, pers. comnnun. Febru- 

 ary 1981. 



Figure 2.— Development of the caudal fin of Ascelichthys rho- 

 dorus: A. 7.2 mm SL; B. 8.5 mm SL; C. 8.7 mm SL; D. 

 10.0 mm SL; E. 13.0 mm SL; F. 16.0 mm SL; G. 62.0 mm 

 SL. EP = epural; HS = haemal spine; HY = hypural; NC = 

 notochord; NS = neural spine; PU = preural centrum; U = ural 

 centrum; UR = uroneural. Ossified elements are stippled. 



13.0 mm SL, the ural centrum and all preural 

 centra are ossified (Fig. 2E). The single ural cen- 

 trum is not fused to the first preural centrum. 

 Hypural bones, neural and haemal spines, and 

 caudal fin rays have also begun ossifying in 13.0 

 mm SL specimens (Fig. 2E). By 16.0 mm SL, a 

 completely ossified pair of uroneurals is visible 

 dorsad to the urostyle (Fig. 2F). All three epurals 

 have begun to ossify, thus completing the caudal 

 complex except for a few unossified secondary 

 caudal fin rays. This caudal complex of a 16.0 

 mm SL early juvenile resembles in all details 

 that of a 62.0 mm SLadult(Fig.2G). In a number 

 of specimens abnormalities of the last neural and 

 haemal spines were observed, e.g., double neural 

 spines from the first preural centra (Fig. 2E) and 

 a large flattened haemal spine (Fig. 2G). 



Spination 



Four similar-sized preopercular spines are 

 ossified on specimens 8.8-9.0 mm SL(Fig. IB). In 

 10.2 mm SL larvae the upper preopercular spine 

 is larger than the lower three (Fig. ID). After 

 transformation the three lower spines are no 

 longer visible, leaving only the prominent upper 

 spine (Fig. IF). The single hook shaped spine is 

 visible on our largest specimens, appearing very 

 similar to the single, recurved spine for which 

 the adults are commonly known. 



On specimens 8.8-9.0 mm SL, one small, pari- 

 etal spine isevident(Fig. lB).Thisspine remains 

 prominent and is joined by a nuchal spine in 10.2 

 mm SL larvae (Fig. ID). The parietal and nuchal 

 spines are no longer visible in larvae >12.8 mm 

 SL(Fig. IF). 



REPRODUCTIVE BEHAVIOR AND 

 LARVAL REARING 



Egg masses of A. rhodorus were found wedged 

 in irregular spaces among rocks under larger 

 boulders, but the eggs adhered only to other 

 eggs, not to rock surfaces. No egg masses were 

 found under boulders lying on sand, shell, 

 gravel, or solid rock surfaces. The egg masses 

 were taken only in a narrow band at the low 

 water level, which was the lowest tidal level dur- 

 ing March and early April 1979. This cobble 

 beach had been repeatedly searched for fish eggs 

 during lower tides before and after the period of 

 the vernal equinox, i.e., in December, January, 

 April, May, and June of previous years, but this 

 kind of egg was only found during the moderate 



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