Leucothoe Leach 1814

Genus Leucothoe Leach, 1814 Type species

Cancer articulosus Montagu, 1804.

According to the World Register of Marine Species (WoRMS), the genus Leucothoe currently comprises no less than 125 species (Horton et al. 2013). The genus itself is morphologically very characteristic and easily recognized, but the distinction of the character states in the many species is usually quite difficult, as it is hard to realize what can be attributed to allometry, sexual diversity or intraspecific variability and what constitutes a stable specific morphological trait.

The first species recorded in the Southern Ocean, L. antarctica Pfeffer, 1888, was described by Pfeffer (1888) from the material collected in South Georgia, during the German International Year Expedition 1882-83. Della Valle (1893: 653) included, without comments, L. antarctica in his long list of L. spinicarpa synonyms, but Stebbing (1906: 168) kept it separate, noting that it “agrees generally with L. spinicarpa ”. Chilton (1912: 478), after checking the type-material, synonymized L. antarctica again with L. spinicarpa, regarded by Walker (1909) and subsequent workers as polymorphic and cosmopolitan (see K.H. Barnard, 1916: 148; Chilton 1921: 59, 1923: 85).

On the other hand, Walker (1907) first identified L. spinicarpa from the collections of the British National Antarctic Expedition 1901-1904 made at Winter Quarters Bay, Mc Murdo Sound, Ross Sea. Since this first record, L. spinicarpa has been found more than 68 times in the Southern Ocean s.l. (see complete detailed records in De Broyer et al. 2007, and on the SCAR-MarBIN/ANTABIF dataportal: http://data. biodiversity.aq/search_engine/es_search).

Analyzing in detail the material from the US Eltanin and Islas Orcadas cruises in the Scotia Sea and the Antarctic Peninsula regions, Holman & Watling (1983) – after stressing that the “cosmopolitan” L. spinicarpa and related species have long been considered “a taxonomic headache” – distinguished three morphological variants of L. spinicarpa and described Leucothoe orkneyi Holman & Watling, 1983.

In more recent years, the prevailing view has been to preserve full species status for most of the described Leucothoe species, at least until a more comprehensive taxonomic study has been undertaken (J.L. Barnard 1972: 137, 1974: 79).

The status of Leucothoe spinicarpa was recently revised by Krapp-Schickel & Menioui (2005) who discussed the L. spinicarpa -group, re-established and redescribed some central Atlantic species formerly synonymized with L. spinicarpa, and by Crowe (2006), who designated a neotype and formally redescribed the species.

In this paper two already defined Antarctic species are redescribed and 5 additional ones presented as new for science.