THEOCOTYLIDAE Petrushevskaya, 1981

Suzuki, Noritoshi, Caulet, Jean-Pierre & Dumitrica, Paulian, 2021, A new integrated morpho- and molecular systematic classification of Cenozoic radiolarians (Class Polycystinea) - suprageneric taxonomy and logical nomenclatorial acts, Geodiversitas 43 (15), pp. 405-573 : 524

Family THEOCOTYLIDAE Petrushevskaya, 1981

Theocotylinae Petrushevskaya, 1981: 216-217. — Afanasieva et al. 2005: S298. — Afanasieva & Amon 2006: 147.

Theocotylidae – De Wever et al. 2001: 280.

TYPE GENUS. — Theocotyle Riedel & Sanfilippo, 1970: 524 [type species by original designation: Theocotyle venezuelensis Riedel & Sanfilippo, 1970: 524 ] = junior subjective synonym of Axocorys Haeckel, 1882: 434 [type species by subsequent monotypy: Axocorys macroceros Haeckel, 1887: 1420 ].

INCLUDED GENERA. — Axocorys Haeckel, 1882: 434 (= Theocotyle synonymized by Petrushevskaya 1981: 220; Theocotylissa n. syn.). — Clistophatna Haeckel, 1882: 433 . — Pentalacorys Haeckel, 1882: 436 (= Hexalacorys n. syn.; Octalacorys synonymized bySanfilippo & Riedel 1982: 175). — Pterocodon Ehrenberg, 1847: 54 . — Thyrsocyrtis Ehrenberg, 1847: 54 (= Podocyrtarium synonymized by Petrushevskaya & Kozlova 1972: 542).

INVALID NAME. — Clistophaena.

DIAGNOSIS. — Theocotylidae consist of three segmented Pterocorythoidea with a small spherical cephalis and an abdomen that is usually two or three times larger than the thorax. The distal segment of the shell is always open. The cephalic initial spicular system consists of MB, A-, V-, D-, double L- and double l-rods. The basal ring is directly connected to the V-, double L- and double l-rods forming a four-leafed clover shape. Each of the double L- and double l-rods tend to be arranged into a straight line. The basal ring is bended along the line with the double l-rod. The A-rod is free and extends vertically to reach near the top of the cephalic cavity. The double AL-arch is visible under a light microscope near the top of the A-rod in the cephalic cavity and merge with the cephalic wall. The D-rod near MB is free from the shell wall and extends downward and is attached to the shell wall. The double L-rod is also free near the edge of the basal ring. These double L-rod extends downward, attaching itself to the shell wall. If present three feet are disconnected from the D- and double L-rods. Three or more feet appear disconnected from all parts of the cephalic initial spicular system. These feet are developed in some genera. Nothing is known about the protoplasmic characteristics.

STRATIGRAPHIC OCCURRENCE. — Middle Paleocene-early Middle Miocene.

REMARKS

Some genera and species that possess a spherical cephalis in the Pterocorythidae (e.g., Calocycloma ) may be misidentified as genera of the Theocotylidae (e.g., Pentalacorys ). The Theocotylidae are distinguished from the Pterocorythidae by the presence of a free vertical A-rod in the cephalic cavity. All Pterocorythidae genera, except for Calocyclas , have an A-rod merged with the cephalic wall. The cephalic structure of the Theocotylidae is very similar to type B of the Pterocorythidae (with a basal ring and double l-rods, see remarks under Pterocorythidae ). However, the former is always associated with double l-rods and a D-rod that is free from the shell wall near the MB. Another fundamental difference between both families is the stability of the cephalic structure. The combination of the cephalic initial spicular system varies, even in a same species of Pterocorythidae , yet it remains unchanged in the Theocotylidae . At the generic level, the differences in Theocotylidae is marked, between the Theocotylissa -form of Axocorys and Pentalacorys , by the geometric relationship of the cephalic basal ring to the shell wall. The basal ring of the Theocotylissa -form of Axocorys is distanced from the shell wall on the apical side of the MB, whereas in Pentalacorys the basal ring is connected to the shell wall. The cephalic initial spicular system was described in Pentalacorys ( Nishimura 1990: figs 28.4-28.7, 30.7; O’Connor 1997a: pl. 9, figs 1-5) and in the Theocotylissa -form of Axocorys ( Nishimura 1990: figs 26.8, 26.9) using scanning electron microscopy. However, the free vertical A-rod in the cephalic cavity is also visible using a light microscope in Pentalacorys ( Ogane et al. 2009b: pl. 54, figs 1e, 2c, pl. 55, fig.1e, pl. 57, fig. 1e, pl. 91, fig. 3b, pl. 92, fig. 3a) and Thyrsocyrtis ( Ogane et al. 2009b: pl. 56, figs 1e, 2d). The evolution between Thyrsocyrtis and Pentalacorys has been partially reported ( Kling 1978: 234-235; Riedel & Sanfilippo 1982: pl. 3, figs 8-12; Sanfilippo & Riedel 1982).

VALIDITY OF GENERA

Axocorys

Theocotyle was previously synonymized with Axocorys byPetrushevskaya (1981: 220). Identical real specimens similar to the type-illustration of Axocorys macroceros ( Haeckel 1887: pl. 68, fig. 1), the type species of Axocorys , have not been seen for over a century. The most similar specimen is illustrated in the supporting image for Axocorys ; it has two segments, not three. The type-illustration of Axocorys is similar to Theocotyle in its deep constriction among segments and a fenestrated aperture. We tentatively synonymize Theocotyle with Theocotylissa . The best definition of Theocotylissa was written by Kozlova (1999: 161), and is translated as follows: “ Three-segmented shell, frequently very large, square or conical. Cephalis small, subspherical, with apical horn. Thorax conical or hemispherical, 2-2.5 times larger than cephalis. Abdomen is the widest segment. Thoracic and sub-abdominal pores large, distributed in alternate longitudinal rows, 13-25 rows on the visible half of the shell. Aperture shape narrower with triangular teeth, sharp thorns, or a smooth rim. External strictures between segments not always marked. ” Kozlova (1999) commented that Theocotylissa differs from Theocotyle in its larger size and more curved abdomen. These differences are not important at the genus level, but the lectotype of Eucyrtidium ficus ( Ogane et al. 2009b: pl. 59, figs 2a, 2b) is marked by a smooth surface. Synonymy among these groups must be investigated in a future study; Axocorys is the oldest available name among them.

Pentalacorys

The living image of Alacorys friderici ( Haeckel 1887: pl. 65, fig. 1) is implausible; its morphological characters are identical to those Pentalacorys . Until a living Alacorys friderici is found, this genus is synonymized with Pentalacorys . Octalacorys was previously synonymized with Pentalacorys by Sanfilippo & Riedel (1982: 175). Pentalacorys and Hexalacorys were simultaneously published in Haeckel (1882: 436 for both). As the type specimen of Podocyrtis pentacantha was examined by Ehrenberg himself in the Ehrenberg collection ( Ogane et al. 2009b: pl. 93, figs 1a-d), Pentalacorys is selected as the valid name.