Observations on the life history of a rare shrimp, Salmoneus carvachoi (Crustacea: Caridea: Alpheidae), a possible simultaneous hermaphrodite

Abstract

This study reports on the life history of a rare alpheid shrimp,Salmoneus carvachoi, in the tropical western Atlantic. At an intertidal flat in Pontal Bay, Ilhéus, Bahia, north-eastern Brazil,S. carvachoiwas collected from within burrows of the axianassid mud shrimpAxianassa australisand the caridean snapping shrimpsAlpheus estuariensisandAlpheus chacei. These and earlier studies that reportedS. carvachoiin dwellings constructed by other larger burrowing crustaceans suggest thatS. carvachoiis a generalist species that establishes facultative symbiotic partnerships with larger burrowing decapods. We collected a total of 52 individuals during the sampling period (1 year); 19 (36.5%) of these shrimps carried embryos underneath the abdomen. The mean ± SD carapace length was 4.7 ± 0.7 and 5.5 ± 0.3 mm in non-brooding and brooding shrimps, respectively. All collected specimens, whether or not brooding embryos, bear appendices masculinae on the endopods of the second pleopods. Burrows harboured only one or two shrimps and never three or more shrimps. Pairs of shrimp that inhabited burrows consisted of two brooding shrimps (N = 3 pairs), two non-brooding shrimps (N = 3), or one brooding and one non-brooding shrimp (N = 1). The presence of appendices masculinae in all collected shrimps, whether or not brooding embryos, and the pairing of brooding shrimp within host burrows suggest thatS. carvachoiis a simultaneously hermaphroditic species.