Latentifistula Nazarov & Ormiston, 1983 sensu Maldonado & Noble (2010)

Noble, Paula, Aitchison, Jonathan C., Danelian, Taniel, Dumitrica, Paulian, Maletz, Jörg, Suzuki, Noritoshi, Cuvelier, Jessie, Caridroit, Martial & O’Dogherty, Luis, 2017, Taxonomy of Paleozoic radiolarian genera, Geodiversitas 39 (3), pp. 419-502 : 462-463

Latentifistula Nazarov & Ormiston, 1983 sensu Maldonado & Noble (2010)

Latentifistula Nazarov & Ormiston, 1983b: 371 . — Maldonado & Noble 2010: 88.

Ouaka Cheng, 1986: 176 .

Trilacertus Cheng, 1986: 177 .

Wonella Kozur & Mostler, 1989: 220 .

TYPE SPECIES. — Latentifistula crux Nazarov & Ormiston, 1983 ( Nazarov & Ormiston 1983b: 372, pl. 1, fig. 1).

AGE AND LOCATION OF TYPE MATERIAL. — Lower Asselian (Lower Permian), Nikol village, Ural River, Southern Urals, Russia.

TAXON CODE. — 184.

STATUS. — Valid.

DIAGNOSIS. — “ Latentifistulidae having an internal framework in the form of a non-porous sphere with three hollow, short rays. These rays usually radiate from the sphere at angles of 120°, producing the same cruciform arrangement of the skeleton. The internal framework is enclosed by a spongy-porous or platy shell. Terminal spines connected by thin rods to the internal hollow rays, well expressed in one species and lacking in others.” ( Nazarov & Ormiston 1983b: 371).

REMARKS The type species is from the Permian of west Texas, but also included in this genus are Mississippian forms, including Latentifistula (Paronaella) impella Ormiston & Lane, 1976 . Holdsworth & Murchey (1988: 784-786) assert that the Mississippian stauraxon radiolarians, which include most of those assigned to Latentifistulida by Nazarov & Ormiston (1983 b, 1985, 1986, 1992) possess solid rectilinear axial filaments inside the rays, connected to a perforate sphere. This observation is contrary to the above definition that describes the rays as hollow tubes and the inner sphere as perforate. In the type species, Latentifistula crux , a younger (Lower Permian) species, axial filaments extend through the majority of the length of the rays, and the hollow tube is very short, present only in the proximal 30 µm of the ray that extends from the sphere. Meanwhile, Won (1983) established Scharfenbergia , and included several of the taxa assigned to Latentifistula , but with a type species based on a triangular form demonstrably without hollow rays. In their revision of the genus, Kozur & Mostler (1989) restrict Latentifistula to triradiate and trilobite forms, and move Paronaella impella to a new genus Wonella . Nestell & Nestell (2010) provide a nice review of the history of these taxa, and essentially adopt the definition of Kozur & Mostler (1989), except that they also include Wonella as a junior synonym. Maldonado & Noble (2010) largely concur with Nestell & Nestell (2010), except they use a more expanded definition that incorporates forms that have three or occasionally four rays. This definition includes two Carboniferous genera described by Cheng (1986), Ouaka , Trilacertus . Both of Cheng’s genera are from his superfamily Archaeopyramacea , which reportedly has a distinct wall architecture described as labyrinthine (see comments under respective genera and the family Latentifistulidae ). Thus, the current usage of Latentifistula incorporates trilobate and triradiate forms, occasionally with a 4 th ray, that have a central sphere that appears either porous or non-porous, and rays or beams that emanate from the sphere inside the arms. These rays may be hollow and/or a latticed extension of the inner sphere (termed a medullary shell by Cheng) and connect distally to a solid thin axial ray.