First record of Tardigrada from Sao Tome (Gulf of Guinea, Western Equatorial Africa) and description of Pseudechiniscus santomensis sp nov (Heterotardigrada: Echiniscidae)

The first six species of tardigrades from Sao Tome Island (Democratic Republic of Sao Tome and Principe) were recorded: the heterotardigrade Pseudechiniscus santomensis sp. nov., and five eutardigrades: Macrobiotus sp., Paramacrobiotus gerlachae (Pilato, Binda & Lisi, 2004), Minibiotus intermedius (Plate, 1889), Doryphoribius sp., Diphascon (Diphascon) sp.. Pseudechiniscus santomensis sp. nov. belongs to the group of species that lack all trunk cirri except filament A; have a pseudosegmental plate with triangular projections on the posterior margin, and dorsal plates ornamented by small dots joined by very delicate striae. The ventral surface of the body has small dots, without striae, forming patches and a reticular design. The new species differs from Pseudechiniscus spinerectus Pilato, Binda, Napolitano & Moncada, 2001, the most similar species, in lacking longitudinal folds on scapular and paired plates; the pseudosegmental plate undivided and with shorter triangular, backward oriented projections that are never erect; only one intersegmental platelet lateral to the median plates 1 and 2; slightly shorter buccal cirri, filament A and papilla of the hind legs; and in having slightly different the ornamentation of the ventral body surface.