In the present study, Xyrichtys novacula (Labridae) were sampled at five locations around the islands of Ibiza and Formentera (western Mediterranean Sea). Isotopic signatures of δ 13 C, δ 15 N and the C:N ratio were analysed in relation to locality, sex and size differences. δ 13 C and δ 15 N partitioning was also studied in the reproductive spawning period. There were significant differences in the δ 13 C signature between lo...

Freshwater bivalves are among the most endangered groups of organisms in North America. Efforts to protect the declining mussel fauna are confounded by ambiguities associated with recognition of distinct evolutionary entities or species. This, in part, is due to the paucity of reliable morphological characters for differentiating taxa. We have employed allozymes and DNA sequence data to search for diagnosably distinct evolutio...