IMIS - Marine Research Groups

The asteroids of the Walter Herwig FFS expedition have been identified in detail, based on the observation of external morphological characters using a binocular microscope. A wide variety of morphological characters was taken into consideration for the identification of the asteroids. For instance, shape and size of the pedicellaria, the skeletal structure (réseau squelettique) and the ossicles that form the mesh (number of spines/ossicle), thickness and aspect of the body wall, the position of the papula, the number of podia rows and the shape of the podia, structure and armature of the marginal plates, number and form of the adambulacral spines as well as the spines of the dental plates, etc. By means of a preexisting identification key of Atlantic asteroids (A.M. Clark, 1994), the observation of the morphological characters permitted to identify the order, the family, the genus and sometimes the species to which the considered individual belonged to. For the time being, there are no existing identification keys for Antarctic asteroids. For this reason, we consulted in addition multiple works of previous Antarctic expeditions (A.M. Clark (1962, 1994), R. Köhler (1906, 1907, 1908, 1911, 1912, 1917, 1920, 1923), W.K. Fisher (1911,1940), Sladen (1889), Mortensen (1932), E. Perrier (1891a), H. Ludwig (1905), Th. Studer (1874), I. Bernasconi (1967, 1964, 1966, 1972), Madsen (1950)) which allowed us to improve the identifications in dubious cases, thanks of their numerous detailed illustrations and descriptions of Antarctic asteroids. Synonymy was resolved by consulting the Register of Antarctic Marine Species (RAMS), that is accessible via internet and that compiles the most recent information about Antarctic asteroid taxonomy (Danis & Jangoux, 2007), delivering us in this way the valid species names.