Test or shell
Simple tests are made by secretion (autogenous tests), agglutination of foreign material (xenogenous tests), or sometimes a combination of both. Past environmental changes can be determined by analysing the composition of fossil tests, including the reconstruction of past Climate change (general concept), climate change. Testate amoebae species have been used to reconstruct hydrological changes over the late Holocene, as a result of individual species possessing a narrow tolerance for ecohydrological conditions such as water-table depth or pH.Evolutionary history
Fossils of arcellinid testate amoebae date back to the Tonian stage of the Proterozoic, around 789-759 million years ago. The fossils indicate that by 730 million years ago, arcellinids had already diversified into major lineages. Testate amoebae are theorized to be mostly polyphyletic (coming from more than one ancestral type), but testaceafilosea, one group of testate amoebae, are theorized to be monophyletic. Ancient tests of terrestrial fauna are commonly found in fossilized amber, although mid-Cretaceous testate amoeba (i.e., ''Diffligia'', ''Cucurbitella'') have been found in ancient lake sediments. It is likely that the group has evolved minimally over the course of the Phanerozoic.Classification
The classification of Arcellinida, as of 2019: * Suborder Phryganellina Bovee 1985 ** Family Phryganellidae Jung 1942 *** ''Phryganella'' Penard 1902 ** Family Cryptodifflugiidae Jung 1942 *** ?''Prantlitina'' Vasicek & Ruzicka 1957 *** ?''Pseudocucurbitella'' Gauthier-Lievre & Thomas 1960 *** ?''Pseudowailesella'' Sudzuki 1979 *** ''Cryptodifflugia'' Penard 1890 [''Difflugiella'' Cash 1904; ''Geococcus (eukaryote), Geococcus'' Francé 1913 non Green 1902] *** ''Meisterfeldia'' Bobrov 2016 *** ''Wailesella'' Deflandre 1928 * Suborder Organoconcha Lahr et al. 2019 ** Family Microchlamyiidae Ogden 1985 *** ''Microchlamys'' Cockerell 1911 [''Pseudochlamys'' Claparede & Lachmann 1859 non Lacordaire 1848 non Comas 1977] *** ''Pyxidicula'' Ehrenberg 1838 non Ehrenberg 1834 non Strelnikova & Nikolajev 1986 *** ''Spumochlamys'' Kudryavtsev & Hausmann 2007 * Suborder Glutinoconcha Lahr et al. 2019 ** Infraorder Volnustoma Lahr et al. 2019 *** Family Heleoperidae Jung 1942 **** ''Awerintzewia'' Schouteden 1906 **** ''Heleopera'' Leidy 1879 ** Infraorder Hyalospheniformes Lahr et al. 2019 *** Family Hyalospheniidae Schulze, 1977 [Nebelidae Taranek 1882] **** ?''Apolimia'' Korganova 1987 **** ?''Deflandria'' Jung 1942 **** ?''Heleoporella'' Couteaux 1978 **** ?''Leidyella'' Jung 1942 **** ?''Metaheleopera'' Bartos 1954 **** ?''Marsipos'' Medioli et al. 1990 **** ?''Paranebela'' Jung 1942 **** ?''Penardiella'' Kahl 1930 **** ?''Pseudogeamphorella'' Décloitre 1964 nomen nudum **** ?''Pseudohyalosphenia'' Stepanek 1967 nomen nudum **** ?''Pterygia'' Jung 1942 non Roeding 1798 non Link 1807 non Laporte 1832 **** ?''Schaudinnia'' Jung 1942 non Schulze 1900 **** ?''Umbonaria'' Jung 1942 **** ''Alabasta'' Duckert et al. 2018 **** ''Alocodera'' Jung 1942a **** ''Apodera'' Loeblich & Tappan 1961 **** ''Certesella'' Loeblich & Tappan 1961 **** ''Cornutheca'' Kosakyan et al. 2016 **** ''Gibbocarina'' Kosakyan et al. 2016 **** ''Hyalosphenia'' Stein 1859 **** ''Longinebela'' Kosakyan et al. 2016 **** ''Mrabella'' Kosakyan et al. 2016 **** ''Nebela'' Leidy 1875 **** ''Padaungiella'' Lara & Todorov 2012 **** ''Planocarina'' Kosakyan et al. 2016 **** ''Porosia'' Jung 1942 **** ''Quadrulella'' Cockerell 1909 [''Quadrula'' Schulze 1875 non Rafinesque 1820] ** Infraorder Excentrostoma Lahr et al. 2019 *** ?''Centropyxiella'' Valkanov 1970 *** ?''Oopyxis'' Jung 1942 *** Family Centropyxidae **** ''Armipyxis'' Dekhtiar 2009 **** ''Centropyxis'' Stein 1857 [''Echinopyxis'' Claparede & Lachmann 1859 non Pantocsek 1913; ''Collaripyxidia'' Zivkovic 1975; ''Toquepyxis'' Laminger 1971] **** ''Conicocassis'' Nasser & Patterson 2015 **** ''Proplagiopyxis'' Schönborn 1964 *** Family Plagiopyxidae **** ''Bullinularia'' Deflandre 1953 [''Bullinula'' Penard 1911] **** ''Geoplagiopyxis'' Chardez 1961 **** ''Hoogenraadia'' GauthierLievre & Thomas 1958 **** ''Paracentropyxis'' Bonnet 1960 **** ''Plagiopyxis'' Penard 1910 **** ''Planhoogenraadia'' Bonnet 1977 **** ''Protoplagiopyxis'' Bonnet 1962 ** Infraorder Longithecina Lahr et al. 2019 *** Family Lesquereusiidae [Paraquadrulidae Deflandre 1953] **** ''Fabalesquereusia'' Snegovaya & Alekperov 2005 **** ''Lesquereusia'' Schlumberger 1845 **** ''Microquadrula'' Golemansky 1968 **** ''Paraquadrula'' Deflandre 1932 **** ''Pomoriella'' Golemansky 1970 *** Family Difflugiidae Wallich 1864 **** ?''Lagenodifflugia'' Medioli & Scott 1983 **** ?''Maghrebia'' Gauthier-Lievre & Thomas 1958 **** ?''Pentagonina'' Bovee & Jahn 1974 [''Pentagonia (amoeba), Pentagonia'' Gauthier-Lievre & Thomas 1958 non Cozzens 1846; ''Falsidifflugia'' Haman 1988] **** ?''Pseudopontigulasia'' Oye 1956 **** ?''Sexangularia'' Awerintzew 1906 **** ?''Suiadifflugia'' Green 1975 **** ?''Zivkovicia'' Ogden 1987 **** ''Armatodifflugia'' Snegovaya & Alekperov 2005 **** ''Difflugia'' Leclere 1815 ex Lamarck 1816 **** ''Mediolus'' Patterson 2014 **** ''Nabranella'' Snegovaya & Alekperov 2009 **** ''Pelecyamoeba'' Snegovaya & Alekperov 2005 **** ''Pontigulasia'' Rhumbler 1895 **** ''Pseudonebela'' Gauthier-Lievre 1954 non Schönborn 1964 ** Infraorder Sphaerothecina Kosakyan et al. 2016 *** ?''Cornuapyxis'' Couteaux & Chardez 1981 *** ?''Cucurbitella'' Penard 1902 non Walpers 1846 *** ?''Ellipsopyxella'' Bonnet 1975 *** ?''Ellipsopyxis'' Bonnet 1965 *** ?''Protocucurbitella'' Gauthier-Lievre & Thomas 1960 non Naumov *** Family Distomatopyxidae Bonnet 1970 **** ''Distomatopyxis'' Bonnet 1970 *** Family Lamtopyxidae Bonnet 1974 **** ''Lamtopyxis'' Bonnet 1974 *** Family Netzeliidae Kosakyan et al. 2016 [Cyclopyxidae Schönborn 1989] **** ''Cyclopyxis'' Bonnet 1953 **** ''Netzelia'' Ogden 1979 *** Family Arcellidae Ehrenberg 1832 **** ''Antarcella'' Ehrenberg 1838 **** ''Arcella'' Deflandre 1928 [''Arcellina'' Carter 1856 non DuPlessis 1876 non Haeckel 1894; ''Cyphidium'' Ehrenberg 1837 non Magnus 1875; ''Leptocystis'' Playfair 1918] *** Trigonopyxidae Loeblich 1964 **** ''Geopyxella'' Bonnet & Thomas 1955 **** ''Trigonopyxis'' Penard 1912 Arcellinida incertae sedis: * ''Argynnia'' Vucetich, 1974 * ''Awerintzewia'' Schouteden, 1906 * ''Geamphorella'' Bonnet, 1959 * ''Jungia (testate amoeba), Jungia'' Loeblich & Tappan 1961 * ''Lagenodifflugia'' Medioli & Scott, 1983 * ''Lamtoquadrula'' Bonnet 1975 * ''Leptochlamys'' West 1901 * ''Maghrebia'' Gauthier-Lievre & Thomas, 1960 * ''Ochros'' Medioli et al. 1990 * †''Palaeoleptochlamys'' Strullu-Derrien et al. 2019 * ''Physochila'' Jung 1942 * ''Pseudawerintzewia'' Bonnet 1959 * ''Sacculus (protist), Sacculus'' Medioli et al. 1990 non Gosse 1851 non Hirase 1927 non Neviani 1930 * ''Schoenbornia'' Decloitre 1964 * ''Swabia (testate amoeba), Swabia'' * Family Bipseudostomatidae Snegovaya & Alekperov 2005 ** ''Bipseudostomatella'' Snegovaya & Alekperov 2005 ** ''Gomocollariella'' Snegovaya & Alekperov 2005 * Family Mississippiellidae Huddleston & Haman 1985 ** ''Mississippiella'' Haman 1982 * Family Shamkiriidae Snegovaya & Alekperov 2005 ** ''Shamkiriella'' Snegovaya & Alekperov 2005References
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