Occurrence and distribution of the tanaid crustacean Leptochelia savignyi on the calcareous hydrozoan Millepora complanata

Tanaids are poorly known crustaceans that have a worldwide, mainly marine d istribution and occur over a wide range of depths (Holdich and Jones, 1983) . They are usually benthic in habit (Holdich and Jones, 1983) and may be tu be-dwelling, burrowing or free-living (Gardiner, 1975; Johnson and Attramad al, 1982a,b). They have a complex life history involving larval (manca), ju venile, and preparatory male and female stages preceeding copulatory males and females. The eggs are borne in a marsupium where early development take s place. Sexual dimorphism appears to be the rule in tanaids and males are usually rare in populations. In some taxa simultaneous protandrous and prot ogynous hermaphrodites have been recorded (Holdich and Jones, 1983). Little is known about the ecology of tanaids except for a few littoral species (H oldich and Jones, 1983). Leptochelia savignyi (Kroyer, 1842) is a small tanaid (2-3 mm in length) th at is nearly cosmopolitan in the north Atlantic and in tropical seas (Holdi ch and Jones, 1983). It is common in the shallow sublittoral and has been r eported living intertidally in self-constructed tubes amongst roots and wee ds on rocks. In Barbados it occupies empty boreholes excavated by the spion id polychaete Dipolydora armata within the coenosteum of living and dead br anches of the calcareous hydrozoan, Millepora complanata (Blake, 1996; Lewi s, 1998). Although a number of species of tanaids are crevice-dwelling, liv ing upon a variety of soft and hard substrata (Holdich and Jones, 1983), th e choice of empty spionid tubes within a coral substratum has not been repo rted previously. The following is an account of the occurrence and aspects of the life history oft. savignyi in relation to its unusual burrow habitat . L. savignyi was identified with the aid of a key provided by Holdich and Jones (1983).