Cryptodifflugia is a genus of arcellinid testate amoebae. It contains all the species previously grouped as the genus Difflugiella, which is now a synonym of Cryptodifflugia.
Description Cryptodifflugia species are characterized by a shell with an oval egg-like shape with a short neck. Their surface is either smooth or adhering foreign particles. The shell can be colorless, yellow or brown, composed of an outer proteinaceous material that is usually lined. The shell's aperture is terminal, and has either a circular or an oval shape. They present pseudopods in the form of ectoplasmic anastomosing reticulopods, i.e. like fine threads that can branch or anastomose (meaning they can form links with each other) to create a dense network.
Classification The classification of the genus, as revised in 2017, identifies 23 species along with some subspecies: Cryptodifflugia angulata Playfair, 1917 – Australia Cryptodifflugia angusta (Schönborn, 1965) Page, 1966 – Bulgaria, Poland, Germany Cryptodifflugia angustastoma Beyens et Chardez, 1982 – Belgium Cryptodifflugia apiculata (Cash, 1904) Page, 1966 – England, Russia, Germany, Romania Cryptodifflugia bassini Bobrov, 2001 – Russia, Japan Cryptodifflugia brevicolla Golemansky, 1979 – Vietnam Cryptodifflugia collum (Chardez, 1971) Bobrov & Mazei, 2017 – Belgium, France Cryptodifflugia compressa Penard, 1902 – cosmopolitan Cryptodifflugia compressa angustioris Tarnogradsky, 1959 – Caucasus, Belgium, Germany, Spitsbergen Cryptodifflugia compressa australis Playfair, 1917 – Australia Cryptodifflugia compressa ovata Playfair, 1917 – Australia Cryptodifflugia crenulata Playfair, 1917 – cosmopolitan Cryptodifflugia crenulata glabra (Schönborn, 1965) Bobrov & Mazei, 2017 – Germany, Poland Cryptodifflugia crenulata globosa Playfair, 1917 – Australia, Poland, Germany, Greenland, Romania, Vietnam, South Georgia, Île de la Possession, Îles Crozet Cryptodifflugia horrida Page, 1966 – Bulgaria, Germany, Poland, Czech Republic, Spitsbergen, Vietnam Cryptodifflugia lanceolata Golemansky, 1970 – cosmopolitan Cryptodifflugia leachi Nicholls, 2006 – Canada Cryptodifflugia minuta (Playfair, 1917) Bobrov & Mazei, 2017 – Australia, Russia, Greenland, United States of America, Île de la Possession, Îles Crozet Cryptodifflugia operculata Page, 1966 – cosmopolitan Cryptodifflugia oviformis Penard, 1890 – cosmopolitan Cryptodifflugia oviformis fusca (Penard, 1890) Bonnet et Thomas, 1956 – cosmopolitan Cryptodifflugia paludosa Golemansky, 1981 – Black Sea Cryptodifflugia patinata (Schönborn, 1964) Bobrov & Mazei, 2017 – Germany, Poland Cryptodifflugia psammophila (Golemansky, 1970) Bobrov & Mazei, 2017 – Baltic Sea, Black Sea, Mediterranean Sea, Caribbean Sea, Atlantic Ocean, Pacific Ocean Cryptodifflugia pusilla Playfair, 1917 – cosmopolitan Cryptodifflugia pusilla conica Playfair, 1917 – Australia Cryptodifflugia sacculus (Penard, 1902) Deflandre, 1953 – cosmopolitan Cryptodifflugia sacculus sakotschawi Tarnogradsky, 1959 – Caucasus Cryptodifflugia splendida (Schönborn, 1965) Page, 1966 – Poland, Germany Cryptodifflugia valida Playfair, 1917 – Australia, Chile Cryptodifflugia voigti Schmidt, 1926 – Germany, Russia, Belgium, Romania Cryptodifflugia vulgaris (Francé, 1913) Volz, 1928 – Germany, Bulgaria, Russia
Excluded taxa Several taxa previously accredited to Cryptodifflugia or Difflugiella have been excluded from the 2017 revision: Difflugiella heynigi Schönborn, 1965 and Cryptodifflugia lamingerae Chardez, 1977 do not match the description of the genus because they are larger and characterized by an apical aboral end of the shell and a prominent long neck with collar; it is possible that these two species will soon be included in the genus Chardezia instead. Cryptodifflugia sakotschawi and C. kelensis were mentioned by Tarnogradsky in 1945 but their descriptions were never published. Cryptodifflugia turfacea Zacharias, 1903 and C. vanhoornei Beyens et Chardez, 1987 are thought to be more probably a different genus because they're characterized by a retort-shaped shell.
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