PATTERNS OF REPRODUCTION IN SMALL JAMAICAN 

 BRITTLE STARS: FISSION AND BROODING PREDOMINATE 



Roland H. Emsonl 

 Department of Zoology 

 King's College, University of London 

 London, WC2R 2LS United Kingdom 



Philip V. Mladenov 



Biology Department 



Mount Allison University 



Sackville, New Brunswick, EOA 3C0 Canada 



Iain C. Wilkie 

 Department of Biological Sciences 

 Glasgow College of Technology 

 Glasgow, G4 OBA United Kingdom 



ABSTRACT 



Brittle stars were collected from coralline algae and from an adjacent 

 turtle grass bed in the back reef lagoon at Discovery Bay, Jamaica. Fissiparous 

 species are numerically predominant in both habitats. These species, although 

 systematically diverse, share strikingly similar life history characteristics, 

 including small adult size (< 4.5 mm disc diameter), low fecundity, yet probable 

 planktotrophic development and asexual propagation. Brooding species are also 

 well represented. They too are small in adult size (< 4.0 mm disc diameter) 

 but are hermaphroditic direct developers, brooding small numbers of young in the 

 bursae. There appears to be selection for small adult size in brittle stars in 

 the habitats studied here. Small size in turn is correlated with modified 

 reproductive patterns like fissiparity and brooding. The relative importance 

 of these patterns in reef habitats is considered and the frequency and geographic 

 distribution of fissiparity and brooding in brittle stars briefly discussed. 



INTRODUCTION 



Coral reefs present many microhabitats which may provide refuges from the 

 pressures of predation generally considered to exist on open surfaces in such 

 areas. Coralline algae, sponges, and coral boulder scree all offer cryptic 

 spaces exploitable by certain species. Such crevices potentially provide both 

 a refuge for juveniles of large species and a habitat in which small species 

 can complete their entire life history. 



During studies on the reproductive biology of the small fissiparous brittle 

 star Ophiocomella ophiactoides (H. L. Clark) at Discovery Bay, Jamaica, W.I. 

 (Mladenov, et al . , 1983; Mladenov and Emson, 1984), we became aware that in the 



1 Contribution number 343 of the Discovery Bay Marine Laboratory of the 

 University of the West Indies. 



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