Ascomycetous yeast communities of marine invertebrates in a southeast Brazilian mangrove ecosystem.

The ascomycetous yeast communities associated with 3 bivalve mollusk, and 4 crab species were studied in the mangrove at Coroa Grande on Sepetiba Bay in Rio de Janeiro, Brazil. These were made up mostly of diverse but sparse and apparently allochtonous yeast populations. The striking exception was a prevalent population of the species Kluyveromyces aestuarii, which predominated the yeast communities of 2 detritus feeding crabs, Sesarma rectum and Uca spp., and the shipworm Neoteredo reynei. However, K. aestuarii was absent from the omnivorous crabs Aratus pisonii and Goniopsis cruentata, and the clam Anomalocardia brasiliana, and was rare in the clam Tagelus plebeius from mostly submerged more sandy sediments. Pichia membranaefaciens, Candida valida-like, Candida krusei, Candida sorbosa, Candida colliculosa-like, Candida famata-like, Kloeckera spp., Candida guilliermondii, Candida albicans, Candida silvae, Geotrichum spp., Rhodotorula spp., Cryptococcus spp., and the methylotrophic yeast Candida boidinii were frequently isolated. The 322 ascomycetous yeast cultures representing 252 isolates from crabs and mollusks were classified as 40 species that fit standard descriptions, and 44 putative new species. The ascomycetous yeast communities of the mangrove ecosystem include many new biotypes that require better taxonomic definition.