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Zelaya, D. G. & D. L. Geiger. 2007. Malacologia 49: 393-443. A systematic revision on the shallow and abyssal species of Scissurellidae and Anatomidae occurring in Sub-Antarctic and Antarctic waters was carried out. This study is based on material from several field trips and museum collections. The shell morphologies of all the species are redescribed and illustrated with scanning electron micrographs. Additional information on the gross anatomy and the radula for seven species is given. A total of six anatomid and seven scissurellid species are recognized as valid in Sub-Antarctic and Antarctic waters, including three new species herein described. Anatomids are represented by the genera Anatoma and Thieleella; the species recognized for the area are: Anatoma conica (d’Orbigny, 1841), characterized by having a globular shell, sculptured with strong axial ribs; Anatoma euglypta (Pelseneer, 1903), has a biconical, delicately cancellate shell; Anatoma shiraseae Numanami & Okutani, 1990, a gradated shell with a distinct spiral ridge on the shoulder and cancellate ornamentation; Thieleella amoena (Thiele, 1912), is globose, strongly sculptured, and with flared lower portion of aperture; Thieleella weddelliana n. sp. is characterized by having a laterally expanded shell, with rounded whorls, deep umbilicus, and strong axial ribs; and Thieleella argentinae n. sp. shows a depressed and widely umbilicated shell, with cancellate sculpture. Scissurellids are represented by the genera Scissurella, Ariella, and Sinezona: Scissurella clathrata Strebel, 1908, is characterized by having an inflated shell with densely cancellate sculpture; Scissurella petermannensis Lamy, 1910, is sculptured with strong axial ribs; Scissurella obliqua Watson, 1886, is nearly smooth and has a shallow umbilicus; Scissurella malvinarum n. sp. also has a smooth shell surface, but the umbilicus is deep and surrounded by 2−6 spiral cords; in Scissurella supraplicata Smith, 1875, the shell is inflated and teleoconch I exhibits strong axial ribs; Ariella subantarctica (Hedley, 1916), has a depressed shell, sculptured with axial ribs and spiral cords, a prominent umbilical callus, and closed foramen; and Sinezona mouchezi (Vélain, 1876), is inflated, sculptured with strong axial ribs, showing a wide umbilicus and a large foramen. The other three scissurellid species previously described from the area – Scissurella eucharista Melvill & Standen, 1912; Scissurella timora Melvill & Standen, 1912; and Scissurella medioplicata Thiele, 1925 – are considered to be synonyms, and Scissurella dalli Bartsch, 1903, is considered a nomen dubium. As part of this revision lectotypes are designated for Thielella amoena, Scissurella timora, Scissurella medioplicata, Scissurella obliqua, and Sinezona mouchezi. Pdf files of many publications are available here. |