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

Belongs within: Spirillinana.

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.: MesolasiodiscusCM01
| Lasiodiscus Reichel 1946 [Lasiodiscinae]HW93
| `--*L. granifer Reichel 1945LT64
| Lasiotrochus Reichel 1946LT64
| `--*L. tatoiensis Reichel 1946LT64
| Glomotrocholina Nikitina 1977HW93
|--Vissariotaxis Mamet 1970CM01, HW93 [Vissariotaxinae]
| `--V. compressaCM01
`--+--Planohowchinia Cózar & Mamet 2001CM01
| `--*P. espielensis Cózar & Mamet 2001CM01
`--+--Howchinia Cushman 1927CM01, 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 1956CM01, LT64 [Monotaxinoididae]
| `--*M. transitorius Brazhkinova & Yartseva 1956LT64
`--Eolasiodiscus Reytlinger 1956CM01, LT64
|--*E. donbassicus Reytlinger 1956 [=Monotaxinoides donbassicus]LT64
|--E. curvusCM01
`--E. priscusCM01

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

*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.

[HW93] Hart, M. B., & C. L. Williams. 1993. Protozoa. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 43–70. Chapman & Hall: London.

[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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