Algospongia is a class of small, calcified fossil organisms of uncertain taxonomic position, assigned in a comprehensive 2010 review to "Animalia" incertae sedis (possibly Protista), but both prior to and post that to an unnamed phylum of Algae; other workers simply list them as Problematica (or Microproblematica), a term historically used for a number of other fossil zoological groups of uncertain placement. They occur in carbonate rocks of the Paleozoic era and their last representatives occur in the Late Permian geological period. Characteristic genera include Aoujgalia, Moravammina and the early-appearing Wetheredella, although the taxonomic validity (and algosponge affinity) of the last named genus has been disputed.
Background and possible taxonomic affinity Algospongia (vernacular name: algosponges) is a taxon of calcified fossil organisms comprising around 90 accepted genera and several hundred species, treated taxonomically as a single class in an unspecified phylum. Originally considered to be fossil sponges or "pseudo algae", an assignment now refuted, their taxonomic position is somewhat unresolved. Of the three most prominent recent researchers, B. Mamet (Belgium) assigns certain families (e.g. Palaeoberesellaceae, Beresellaceae and Issinellaceae) to Chlorophyta (green algae) as an order of that phylum (Palaeosiphonocladales), at least one other family (Ungdarellaceae) to Rhodophyta (red algae), and some other genera (Groenlandella, Labyrinthoconus) simply to "Microproblematica". Meanwhile, D. Vachard (France) and P. Cózar (Spain) treated Algospongia (such as the family Calcifoliaceae) as Algae incertae sedis, before deciding (in 2010) against any algal affinity and reassigning them to the [zoological] protists, as a group possibly paralleling the Foraminifera. Since that paper, Cózar has continued to use zoological terminology in his published works, while Vachard has once again assigned the group to the Algae incertae sedis, lying hypothetically mid-way between the extant Rhodophyta and Chlorophyta. In this work, the author states: "The Algospongia Termier et al. are subdivided into two orders: Moravamminales and Aougaliiales, six suborders (including Beresellina, Donezellina and Calcifoliina) and 17 families. However, some authors still consider that the Aougaliida are red algae, and Moravamminales green algae." A number of the genera allocated to Algospongia in the present treatment (which follows Vachard & Cózar, 2010 in the main) were recently (2021) treated as either Foraminifera, or as red or green algae, in the World Register of Marine Species, a situation that is currently under revision. For convenience in the present article, the published summary of Vachard & Cózar (2010) is presented below (with modifications as necessary), which treats the relevant genera as a single class (not split e.g. among different botanical phyla) under zoological nomenclature, however also recognizing that the botanical treatment now preferred by Vachard may in fact be correct, an approach currently adopted in the Interim Register of Marine and Nonmarine Genera (IRMNG).
Members of the group occur in the fossil record from the Ordovician to the Late Permian periods, although only Wetheredella is prominent prior to the start of the Devonian. They share a common wall appearance (frequently perforated), possess functional apertures between successive chambers or cells, and appear to have had a sessile or attached mode of life, at depths considered too deep for green algae but possibly overlapping those of red algae, while morphologically they do not exactly resemble members of either of those groups. The most comprehensive recent taxonomic treatment of the group is by Vachard & Cózar, 2010, in which they are treated as a single class divided into 2 orders (Aoujgalida and Moravamminida, corresponding to Aoujgaliales and Moravamminales in botanical nomenclature) typified by the genera Aoujgalia and Moravammina, respectively, plus a number of suborders; this treatment is reproduced below, together with adjustments based on more recent literature of relevance.
Morphology Algosponges are described as a group of sessile or attached microorganisms with characteristic calcified walls described as "yellowish, apparently granular" that are frequently perforated, and possess either lateral or terminal apertures between successive chambers or cells. The order Aoujgalida (bot.: Aoujgaliales) is characterised by Vachard & Cózar as follows (emended description):
while the order Moravamminida (bot.: Moravamminales) is described as follows (emended description):
Classification The treatment below is based on that published by Vachard & Cózar in 2010, (alternative, botanical treatment indicated separated by "/"); more recent genera (post 2010) and, in some cases, corrections have been added per other available sources. If the group is considered zoological (i.e. non-Algal), nomenclature should follow the provisions of the International Code of Zoological Nomenclature (ICZN); if treated as Algae incertae sedis as per Vachard et al., 2016 and Vachard, 2021, the botanical Code (now International Code of Nomenclature for algae, fungi, and plants or ICNafp) applies. The possibly analogous Foraminifera (protists or Protozoa in many classifications) are members of the clade SAR, which is presently assigned to the kingdom Chromista in many classifications.
Kingdom incertae sedis (Animalia or Protista/Protozoa, or Plantae, inferred from Vachard, 2021) Phylum incertae sedis ("Algae incertae sedis" in Vachard, 2021) Class Algospongia Termier, Termier & Vachard, 1977 Order Aoujgaliida Termier, Termier & Vachard, 1975 / bot.: Aoujgaliales Termier et al., 1975 ex Vachard & Cózar, 2010 Suborder Aoujgaliina G. Termier et al., 1975, nomen translat. Vachard & Cózar, 2010 / bot.: -inae? Family Aoujgaliidae Termier, Termier & Vachard, 1975 / bot.: Aoujgaliaceae Termier, Termier & Vachard, 1975 Aoujgalia G. Termier & H. Termier, 1950 (syn.: Mametella Brenkle, 1977) Asteroaoujgalia Brenckle, 2004 Costacheoides Vachard & Cózar, 2010 Epistacheoides A.A. Petryk & B.L. Mamet, 1972 Pseudostacheoides A.A. Petryk & B.L. Mamet, 1972 Roquesselsia Termier, Termier & Vachard, 1977 Sinustacheoides Termier, Termier & Vachard, 1977 Stacheoides R.H. Cummings, 1955 (syn.: Chantonia Termier, Termier & Vachard, 1977; Stacheoidella Mamet & Roux in Mamet et al., 1987; Stacheoides Cummings, 1951, nom. nud.) Valuzieria Termier, Termier & Vachard, 1977 (listed under accepted name Aoujgalia in Vachard & Cózar, 2010, Table 3, but reinstated as a distinct genus by Vachard et al., 2016 Family Cuneiphycidae Vachard & Cózar, 2010 / bot.: Cuneiphycaceae D. Vachard & P. Cózar, 2010 ('Cuneiphycidae') Cuneiphycus J.H. Johnson, 1960 Iberiaella L.G. Racz, 1984 (syn.: Contortiporidium Maslov, 1973 - latter name not in Vachard & Cózar, 2010) Masloviporidium J.R. Groves & B.L. Mamet in D.F. Toomey & M.H. Nitecki, 1985 (syn.: Pseudodonezella Mamet & Herbig, 1990; latter name incorrectly listed as syn. of Frustulata (Calcifoliidae) in Vachard & Cózar, 2010, Table 3) Multiporidium Vachard & Cózar, 2010 Family Stacheiidae Loeblich & Tappan, 1961 / bot.: Stacheiaceae Loeblich & Tappan, 1961 Fourstonella R.H. Cummings, 1955 (syn.: Amorfia L. Rácz, 1964; Chuvashovia Vachard & Montenat, 1981; Eflugelia (sometimes as "Efluegelia") Vachard in Massa & Vachard, 1979; Foliophycopsis Gaillot, 2006; Parastacheia B. Mamet & A. Roux, 1977) Stacheia Brady, 1876 (syn.: Conilalia Vachard in Massa & Vachard, 1979) Family Ungdarellidae Maslov, 1956 / bot.: Ungdarellaceae Maslov, 1954 Cheggatella J. Poncet, 1989 Cheggatellina B. Mamet & A. Preat, 2013 (latter name not in Vachard & Cózar, 2010) Erevanella V.P. Maslov, 1962 Foliophycus J.H. Johnson, 1960 Komia K.B. Korde, 1951 (syn.: Pseudokomia L. Rácz, 1964; Turkomia Gaillot, 2006) Petschoria K.B. Korde, 1951 Ungdarella V.P. Maslov, 1956 (syn.: Pseudoungdarella Ivanova, 1999; Suundukella B. Chuvashov & A. Anfimov, 2007; Ungdarelloides B. Chuvashov & A. Anfimov, 2007; Urtasimella B. Chuvashov & A. Anfimov, 2007) Ungdarellita Mamet & Villa, 2004 Suborder Calcifoliina G. Termier et al., 1977 nomen translat. Vachard & Cózar, 2010 / bot.: -inae? Family Calcifoliidae Shuysky in Chuvashov et al., 1987 / bot.: Calcifoliaceae Termier, Termier & Vachard, 1977 Calcifolium M.S. Svecov & L.M. Birina, 1935 Falsocalcifolium D. Vachard & P. Cózar, 2005 Frustulata V.D. Saltovskaja in M.R. Dzhalolov, 1984 Family Fasciellidae Shuysky, 1999 / bot.: Fasciellaceae Shuysky, 1999 Fasciella R.M. Ivanova, 1973 (syn.: Shartymophycus E.L. Kulik in O.L. Einor, 1973) Fascifolium D. Vachard, A. Karim & P. Cózar in Vachard & Cózar, 2010 Order Moravammida Pokorný, 1951 / bot.: Moravamminales Pokorný, 1951 ex Vachard in Termier et al., 1975; syn.: Palaeosiphonocladales Shuysky, 1985 Suborder Beresellina Vachard, 1994, nomen. translat. Vachard & Cózar, 2010 / bot.: -inae? Family Beresellidae Maslov & Kulik, 1956 / bot.: Beresellaceae Deloffre, 1988 Ardengostella Vachard in Perret & Vachard, 1977 Beresella V.N. Makhaev ex V.P. Maslov & E.L. Kulik, 1956 Dvinella I.V. Khvorova, 1949 (syn.: Eomizzia R. Endô & M. Horiguchi, 1957) Trinodella (Maslov & Kulik, 1956) Vachard & Cózar, 2010 (previously a subgenus of Dvinella) Uraloporella K.B. Korde, 1950 (syn.: Samarella V.P. Maslov & E.L. Kulik, 1956) Suborder Donezellina G. Termier et al., 1975, nomen translat. Vachard & Cózar, 2010 / bot.: -inae? Family Claracrustidae Vachard in Vachard et al., 2001 / bot.: Claracrustaceae Vachard in Vachard et al., 2001 Asphaltinella B. Mamet & A. Roux, 1978 Claracrusta Vachard & Montenat, 1981 (syn.: Berestovia O.I. Berchenko in Y.V. Teslenko, 1982) Denisella Vachard & Cózar, 2010 Kleinbergella B. Mamet & F. Boulvain, 1992 Peristacheia B. Mamet & A. Roux, 1983 Pokorninella Vachard in Perret & Vachard, 1977 Precorninella Vachard, 1991 Ungdarellina B. Mamet, 2002 Family Donezellidae Termier, Termier & Vachard, 1975 / bot.: Donezellaceae Termier, Termier & Vachard, 1975 Alanyana T. Güvenç, 1967 (listed under accepted name Donezella in Vachard & Cózar, 2010, Table 3, but only as "possible synonym" in text) Donezella V.P. Maslov, 1929 ex Vachard in Meissami et al., 1978 (syn.: Goksuella T. Güvenç, 1966) Kamaenella B.L. Mamet & A. Roux, 1975 Praedonezella E.L. Kulik in O.L. Einor, 1973 Suborder Moravamminina Pokorný, 1951, nomen translat. Vachard & Cózar, 2010 / bot.: -inae? Family Anthracoporellopsidae Shuysky, 1985 / bot.: Anthracoporellopsidacae Shuysky, 1985 ex Vachard in Vachard et al., 1989 Anthracoporellopsis V.P. Maslov, 1956 Brazhnikovia O.I. Berchenko, 1981 Catenaella V.P. Shuysky, 1987 (as "Catenaenella" (misspelling) in Vachard & Cózar, 2010, Table 3) Crassikamaena P.L. Brenckle, 1985 Culmiella V.P. Shuysky in V.P. Shuysky & D.I. Schirschova in V.N. Dubatolov & T.A. Moskalenko, 1988 Dokutchaevskella O.I. Berchenko, 1981 Einoriella V.D. Saltovskaja in M.R. Dzhalolov, 1984 (as "Einorella" (misspelling) in Vachard & Cózar, 2010, Table 3) Evlania Bykova, 1952 Evlaniopsis Vachard & Montenat, 1981 Groenlandella B.L. Mamet & L. Stemmerik, 2000 Pseudonanopora B.L. Mamet & A. Roux, 1975 Family Issinellidae Deloffre, 1987 / bot.: Issinellaceae Deloffre, 1987 Amarellina B. Mamet, 1995 Calcicaulis V.P. Shuysky & D.I. Schirschova in V.P. Shuysky, 1987 Dreesenulella Vachard, 1991 (syn.: Baculella Conil & Dreesen in Dreesen et al., 1985) note: synonymy reversed from that given in Vachard & Cózar, 2010, per Vachard et al., 2016 Eouraloporella O.I. Berchenko, 1981 Issinella E.A. Reitlinger, 1954 Issinellina V.P. Shuysky in V.P. Shuysky & D.I. Schirschova in V.N. Dubatolov & T.A. Moskalenko, 1988 Jansaella B.L. Mamet & A. Roux, 1975 Lemosquetella B. Mamet & A. Sebbar, 1998 Luteotubulus Vachard in Vachard et al., 1977 Serrisinella Vachard, 1991 Tubus B.I. Tchuvashov, 1985