Studies on portunid crabs from the Eastern Pacific. II. Significance of the unusual distribution ofEuphylax dovii

✍ Scribed by E. A. Norse; V. Fox-Norse

• Publisher: Springer-Verlag
• Year: 1977
• Tongue: English
• Weight: 271 KB
• Volume: 40
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00395730

✦ Synopsis

Euphylax do~i

Stimpson (Brachyura: Portunidae: Podophthalminae), a tropical Eastern Pacific swimming crab, has distinctive morphological adaptations for pelagic existence. Crabs in collections from the open ocean had a sex ratio approximating 1:1, with no crabs bearing eggs. Samples from the continental shelf of Colombia contained thousands of females, mostly ovigerous, but no males. Egg attachment has posed a major problem in the evolution of decapod crustaceans, and the two genera of portunid crabs thus far observed cannot attach eggs unless females can bury partly in soft sediments. This suggests that mated E. do~i females must migrate into shallow shelf waters to encounter sediments necessary for spawning. The high energetic cost of swimming while carrying eggs and the presence of abundant food for larvae are factors favoring residence of females in shelf waters until hatching is complete.