Orchestia Problem

Lowry, J. K. & Fanini, Lucia, 2013, Substrate dependent talitrid amphipods from fragmented beaches on the north coast of Crete (Crustacea, Amphipoda, Talitridae), including a redefinition of the genus Orchestia and descriptions of Orchestia xylino sp. nov. and Cryptorchestia gen. nov., Zootaxa 3709 (3), pp. 201-229 : 202

The Orchestia Problem

For many years talitrid species were placed mainly in Orchestia Leach, 1814 or Talorchestia Dana, 1853 . J.L. Barnard (1958) reported 57 species in Orchestia and 41 in Talorchestia , 80% of the known species at that time. Starting in the early 1970’s Bousfield (see Lowry & Bopiah 2012 for a review) began to develop a generic structure for talitrids, which indicated more concise geographic ranges for the genera. Morino & Miyamoto (1988) revised Talorchestia and confined it to 4 species in the western Pacific Ocean, subsequently increased to 9 species (see Lowry & Bopiah 2013). It is now apparent that the approximately 65 talitrid genera are not individually widespread, but occur in well-defined ranges as a result of vicariant dispersal. The exceptions are almost always taxa with anthropogenic dispersal.

Bousfield (1982) thought of Orchestia as a coastal Atlantic-Mediterranean genus of about 15 species. His definition took in most, but not all of the European species. Although his definition also took in five New Zealand species Bousfield did not recognise them.

Currently Orchestia (sensu lato) contains about 28 species from varied habitats and widespread geography. In this paper we redefine Orchestia to include a marine supralittoral group, from eastern North America, some northeastern Atlantic islands, western Europe and the Mediterranean Sea, plus the anomalous outlier in New Zealand. In addition, we establish the new genus Cryptorchestia , to include nine terrestrial species, previously embedded in Orchestia , from Europe and some islands in the Atlantic Ocean.