(Clockwise from bottom left) Equatorial, axial and tangential axial sections of Eolasiodiscus donbassicus, from Loeblich & Tappan (1964).

Belongs within: Fusulinida.

The Lasiodiscidae are a group of fusulinids known from the Lower Carboniferous to the Upper Permian in which the test is primarily composed of a single tubular chamber (Loeblich & Tappan 1964).

Characters (from Loeblich & Tappan 1964): Test planispiral to conical, proloculus followed by unsegmented tubular chamber; wall calcareous, with microgranular layer and radially built vitreous layer, latter concentrated as umbilical fillings perforated by canal-like fissures in advanced forms but consisting only of bridges across spiral suture in simple forms; aperture at open end of tubular chamber, with supplementary sutural openings.

    |  i. s.: Mesolasiodiscus CM01
    |         Lasiodiscus Reichel 1945 LT64
    |           `--*L. granifer Reichel 1945 LT64
    |         Lasiotrochus Reichel 1946 LT64
    |           `--*L. tatoiensis Reichel 1946 LT64
    |--Vissariotaxis compressa CM01
    `--+--Planohowchinia Cózar & Mamet 2001 CM01
       |    `--*P. espielensis Cózar & Mamet 2001 CM01
       `--+--Howchinia Cushman 1927 CM01, LT64 (see below for synonymy)
          |    |--*H. bradyana (Howchin 1888) [=Patellina bradyana] LT64
          |    `--H. gibba (von Möller 1879) [=Tetrataxis conica var. gibba, *Monotaxis gibba] LT64
          `--+--Monotaxinoides Brazhnikova & Yartseva 1956 CM01, LT64
             |    `--*M. transitorius Brazhkinova & Yartseva 1956 LT64
             `--Eolasiodiscus Reytlinger 1956 CM01, LT64
                  |--*E. donbassicus Reytlinger 1956 [=Monotaxinoides donbassicus] LT64
                  |--E. curvus CM01
                  `--E. priscus CM01

Howchinia Cushman 1927 CM01, LT64 [incl. Monotaxis Vissarionova 1948 nec Bennett 1830 nec Hulst 1898 nec Hampson 1900 LT64]

*Type species of generic name indicated


[CM01] Cózar, P., & B. L. Mamet. 2001. Planohowchinia (Lasiodiscidae, Foraminiferida), a new Late Viséan genus, southwestern Spain. Journal of Foraminiferal Research 31 (3): 228–232.

[LT64] Loeblich, A. R., Jr & H. Tappan. 1964. Sarcodina: chiefly “thecamoebians” and Foraminiferida. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt C. Protista 2 vol. 1. The Geological Society of America and The University of Kansas Press.

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