Cyst of Litosphaeridium arundum, from here.

Belongs within: Peridiniphycidae.
Contains: Areoligeraceae.

The Leptodinioideae are a group of dinoflagellates known as fossil cysts from the Middle Jurassic to the Miocene (Fenson et al. 1993).

Characters (from Fensome et al. 1993): L-type ventral organisation; neutral to sinistral torsion. Four climactal (1u, B, C, A) plates present contacting the apical pore complex, not including Cv which may or may not be present; first apical homologue (1u) not significantly reduced in size compared to other apical plates. Six precingular plates, of which the distalmost, the sixth precingular homologue (li) is pentagonal and broadly geniculate at its anterior; sixth precingular homologue almost invariably contacts first apical homologue (1u). Six cingular plates; ends of cingulum not overhanging each other, sulcus straight and relatively broad throught its length. Five or six Kofoid postcingular plates; first postcingular homologue (Iu) almost invariably small, commonly within the sulcus. Fundital plates in sexiform configuration.

    |--Ambonosphaera Fensom 1979FT93
    |--Acanthaulax Sarjeant 1968 [=Acanthogonyaulax Sarjeant 1966 non (Kofoid) Graham 1942]FT93
    |--‘Amphorula’ Dodekova 1969 non Grove 1922FT93
    |--Carpodinium Cookson & Eisenack 1962FT93
    |--Cernicysta Stover & Helby 1987FT93
    |--Clathroctenocystis Wiggins 1972FT93
    |--Cymososphaeridium Davey 1982FT93
    |--Diacanthum Habib 1972FT93
    |--Dichadogonyaulax Sarjeant 1966 [incl. Brotzenia Horowitz 1975 non Hofker 1954 (ICZN)]FT93
    |--Durotrigia Bailey 1987FT93
    |--Egmontodinium Gitmez & Sarjeant 1972FT93
    |--Emmetrocysta Stover 1975FT93
    |--Eodinia Eisenack 1936FT93
    |--Lanterna Dodekova 1969FT93
    |--Limbodinium Riding 1987FT93
    |--Meiourogonyaulax Sarjeant 1966FT93
    |--Occisucysta Gitmez 1970FT93
    |--Omatia Cookson & Eisenack 1958FT93
    |--Perisseiasphaeridium Davey & Williams 1966FT93
    |--Rotosphaeropsis Davey 1988FT93
    |--Stiphrosphaeridium Davey 1982FT93
    |--Energlynia Sarjeant 1976FT93
    |    `--E. acollaris (Dodekova) Sarjeant 1978EB93
    |--Lophocysta Manum 1979FT93
    |    `--L. sulcolimbata Manum 1979EB93
    |--Eatonicysta Stover & Evitt 1978FT93
    |    `--E. urnulae [=Membranilarnacia ursulae]G87
    |--Tehamadinium Jan du Chêne, Becheler et al. in Jan du Chêne, Masure et al. 1986FT93
    |    `--T. brixii (Below 1982) Jan du Chêne et al. 1986FT93
    |--Lithodinia Eisenack 1935FT93
    |    `--L. jurassica Eisenack 1965FT93
    |--Endoscrinium (Klement 1960) Vozzhenikova 1967 [incl. Athigmatocysta Duxbury 1977]FT93
    |    `--E. luridum (Deflandre 1939) Gocht 1970RC02
    |--Conosphaeridium Cookson & Eisenack 1969FT93
    |    `--C. striatoconum (Deflandre & Cookson 1955) Cookson & Eisenack 1969RC02
    |--Herendeenia Wiggins 1969FT93
    |    `--H. postprojecta Stover & Helby 1987RC02
    |--Ochetodinium Damassa 1979FT93
    |    `--O. romanum Damassa 1979FT93
    |--Rigaudella Below 1982FT93
    |    `--R. aemula (Deflandre 1939) Below 1982RC02 [=Adnatosphaeridium aemulum (Deflandre) Williams & Downie 1969FT93]
    |--Sirmiodinium Alberti 1961FT93
    |    `--S. grossii Alberti 1961RC02
    |--Systematophora Klement 1960 [incl. Polystephanosphaera Sarjeant 1960]FT93
    |    |--S. areolata Klement 1960EB93
    |    `--S. placacantha (Deflandre & Cookson 1955) Davey et al. 1969FT93
    |--Leptodinium Klement 1960FT93
    |    |--L. mirabile Klement 1960FT93
    |    `--L. posterosulcatum Snape 1972RC02
    |--Rhynchodiniopsis Deflandre 1935FT93
    |    |--R. aptiana Deflandre 1935FT93
    |    |--R. cladophora (Deflandre 1939) Below 1981FT93
    |    `--R. regalis (Gocht) Jan du Chêne et al. 1985EB93
    |--Oligosphaeridium Davey & Williams 1966FT93
    |    |--O. abaculum Davey 1979FT93
    |    |--O. complex (White 1842) Davey & Williams 1966RC02
    |    `--O. pulcherrimum (Deflandre & Cookson 1955) Davey & Williams 1966RC02
    |--Kleithriasphaeridium Davey 1974 [incl. Diversispina Benson 1976]FT93
    |    |--K. eoinodes (Eisenack 1958) Davey 1974RC02
    |    |--‘Hystrichosphaeridium’ readei Davey & Williams 1966FT93
    |    `--K. tubulosum (Cookson & Eisenack 1969) Stover & Evitt 1978RC02
    |--Litosphaeridium Davey & Williams 1966FT93
    |    |--L. arundum (Eisenack & Cookson 1960) Davey 1979RC02
    |    |--L. conispinum Davey & Verdier 1973RC02
    |    `--L. siphoniphorum (Cookson & Eisenack 1958) Davey & Williams 1966RC02
    |--Ctenidodinium Deflandre 1939 [incl. Hystrichogonyaulax Sarjeant 1969]FT93
    |    |--‘Hystrichogonyaulax’ cladophoraT87
    |    |--C. combazii Dupin 1968FT93
    |    |--C. continuum Gocht 1970EB93
    |    |--C. elegantulum Millioud 1969EB93
    |    `--C. ornatum (Eisenack 1935) Deflandre 1939FT93
    |--Wanaea Cookson & Eisenack 1958FT93
    |    |--W. acollaris Dodekova 1975RC02
    |    |--W. clathrataG87
    |    |--W. digitataG87
    |    |--W. fimbriataG87
    |    `--W. spectabilisG87
    `--Areosphaeridium Eaton 1971FT93
         |--A. diktyoplokus (Klumpp 1953) Eaton 1971G87, FT93
         `--+--A. arcuatum Eaton 1971G87, FT93
            `--+--‘Glaphyrocysta’ intricata [=Cyclonephelium intricatum]G87
               `--+--A. multicornutum Eaton 1971G87, FT93
                  `--+--A. fenestratumG87

*Type species of generic name indicated


Edwards, D., J. G. Baldauf, P. R. Brown, K. J. Dorning, M. Feist, L. T. Gallagher, N. Grambast-Fessard, M. B. Hart, A. J. Powell & R. Riding. 1993. ‘Algae’. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 15–40. Chapman & Hall: London.

[FT93] Fensome, R. A., F. J. R. Taylor, G. Norris, W. A. S. Sarjeant, D. I. Wharton & G. L. Williams. 1993. A classification of living and fossil dinoflagellates. Micropaleontology Special Publication 7: i–viii, 1–351.

[G87] Goodman, D. K. 1987. Dinoflagellate cysts in ancient and modern sediments. In: Taylor, F. J. R. (ed.) The Biology of Dinoflagellates pp. 649–722. Blackwell Scientific.

[RC02] Riding, J. B., & J. A. Crame. 2002. Aptian to Coniacian (Early–Late Cretaceous) palynostratigraphy of the Gustav Group, James Ross Basin, Antarctica. Cretaceous Research 23: 739–760.

[T87] Taylor, F. J. R. 1987. Dinoflagellate morphology. In: Taylor, F. J. R. (ed.) The Biology of Dinoflagellates pp. 24–91. Blackwell Scientific.

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