FISHERY BULLETIN: VOL. 79, NO. 3 



coast of central eastern Florida between lat. 

 27°14.8' N, long. 79°56.7' W and lat. 27°15.1' N, 

 long. 79°58.0' W from depths of 115.2-96.9 m. The 

 specimen, collected from a substrate consisting of 

 encrusted shell hash and Oculina coral, carried 

 approximately 80 pale fuchsia eggs which dark- 

 ened slightly before hatching on 20 June in the 

 laboratory. After yielding larvae, this specimen 

 was compared with specimens of M. sculptipes de- 

 posited in the National Museum of Natural His- 

 tory, Washington, D.C., which had been illustrated 

 by Rathbun (1930: USNM 20719, 60777) and was 

 found to agree in all important respects. 



Three groups of 24 larvae were isolated, one 

 each in 24 compartmented plastic boxes, and 

 placed into controlled temperature units (CTU) at 

 20°, 25°, or 25°-30° C ( ±0.5° C) under diel illumina- 

 tion. Surf zone seawater (of 36%o) was filtered 

 through glass wool fiber, stored in large Nalgene'* 

 bottles in the laboratory, and used to culture 

 larvae. 



Larvae received fresh seawater and were fed 

 freshly hatched San Francisco brand Artemia 

 nauplii daily. Molts and deaths of each larva and 

 color notes of representative larval stages under 

 refracted and reflected white light were recorded. 

 Dead individuals and molts were preserved in 70% 

 ethanol and were measured with a microscope 

 fitted with an eyepiece micrometer. Measurements 

 given are the arithmetic mean values of the 

 number of specimens examined in each stage. 

 Larvae were cleared in 50% lactic acid solution to 

 which lignin pink stain was added to aid in draw- 

 ing larval characters. Whole mounts (50x) and 

 dissected appendages (drawn at 200 x and checked 

 for details at 400 x) were mounted in CMCP 

 mounting medium and drav^Ti with Wild M5 and 

 M20 microscopes equipped with camera lucidas. 



The spent female and a complete series of larval 

 stages are deposited in the United States National 

 Museum, USNM 171393. 



RESULTS OF REARING EXPERIMENT 



Micropanope sculptipes larvae hatched as pre- 

 zoeae of short, but not precisely determined, dura- 

 tion. They developed through four zoeal stages, 

 after which metamorphosis to a megalopa oc- 

 curred. 



"•Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



Figure 1 and Table 1 indicate that survival was 

 poor and was apparently influenced by tempera- 

 ture. Most successful development occurred at 25° 

 C; survival was notably lower at 20° C, and no 

 larvae developed beyond first zoeae at 25°-30° C. 

 Even at the "optimum" temperature of 25° C, 50% 

 mortality occurred during the first zoeal stage and 

 only one individual survived to the megalopa 

 stage. At this temperature developmental dura- 

 tion was 26 d from hatching to megalopa; no crab 

 stage was attained. 



The duration of larval stages was variable. First 

 stage zoeae generally required 6 or 7 d to success- 

 fully molt to second stage zoeae; however, one in- 

 dividual at 20° C required 15 d and another indi- 

 vidual at 25° C persisted for 10 d before molting. 

 These two zoeae did not survive beyond the second 

 zoeal stage. Second and third zoeal stages gener- 

 ally remained as such 5 d before molting, although 

 20° C larvae took slightly longer than 25° C larvae. 

 Fourth zoeal stages survived between 6 and 8 d 

 before either molting or dying. The one fourth 

 stage zoea at 25° C remained in stage 6 d before 

 molting to megalopa. 



Larval development was apparently regular 

 and no larvae were observed to either skip a devel- 

 opmental stage or molt without developing into a 

 more advanced stage. One zoea in the first stage at 

 25° C was grossly deformed when it molted to 

 second stage at age 6 d and it died 7 d later without 

 molting again. All other zoeae possessed similar 

 morphological characters, so that temperature 

 difference produced no variations. Many zoeae 

 died during preecdysis or in ecdysis to the next 

 larval stage. Five of the nine fourth stage zoeae 

 died while attempting the molt to megalopae. 

 Megalopal telsons, antennae, and chelipeds were 

 observed beneath the transparent fourth zoeal 

 exoskeletons of these specimens, indicating a ter- 

 minal larval stage. No fifth zoeal stage larvae were 

 observed. 



The results of this study indicate that M. 

 sculptipes larvae progress through four larval 

 stages and thus are similar to the majority of 

 xanthid species. Four zoeal stages have been con- 

 sidered characteristic in Xanthidae (Hyman 1925; 

 Lebour 1928) and include many species, e.g., 

 Panopeus herbstii (Costlow and Bookhout 1961a), 

 Eurypanopeus depressus (Costlow and Bookhout 

 1961b), Rhithropanopeus harrisii (Chamberlain 

 1962), Hexapanopeus angustifrons (Costlow and 

 Bookhout 1966), Leptodius [= Pseudomedaeus] 

 agassizii (Costlow and Bookhout 19QS),Neopanope 



488 



