THALASSOTHAMNIDAE Haecker, 1906

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 : 468

Family THALASSOTHAMNIDAE Haecker, 1906

Thalassothamnidae Haecker, 1906: 879 ; 1908: 394-400. — Popofsky 1908: 203-205. — Lankester et al. 1909: 144. — Hollande & Enjumet 1953: 108 [in Collodaria ]. — Campbell 1954: D46 [in Collodaria ].— Kozur & Mostler 1981: 5; 1982: 406 [in Entactinaria ]. — Cachon & Cachon 1985: 284 [in Sphaerocollina]. — Petrushevskaya 1986: 122- 123. — De Wever et al. 2001: 175, 177 [in Entactinaria ].

Cytocladidae Schröder, 1908: 209.

TYPE GENUS. — Thalassothamnus Haecker, 1906: 888 [type species by subsequent designation ( Campbell 1954: D46): Thalassothamnus genista Haecker, 1906: 881 ].

INCLUDED GENERA. — Cytocladus Schröder, 1908: 219 . — Thalassothamnus Haecker, 1906: 888 .

DIAGNOSIS (CONTRIBUTED BY YASUHIDE NAKAMURA). — A radiolarian with a single large diverging spicule. The several radial spines of the diverging spicule merge together at several points.

STRATIGRAPHIC OCCURRENCE. — Holocene-Living.

REMARKS (CONTRIBUTED BY YASUHIDE NAKAMURA)

The genus Cytocladus was classified into the family Thalassothamnidae Haecker 1906 . It should be noted that Cytocladus is covered with a spherical extracapsular protoplasm and that its skeletal architecture is similar to the Sphaerozoidae and Thalassosphaeridae . These features suggest a close relationship to Collodaria ( Cachon & Cachon 1985; Petrushevskaya 1984; Nakamura et al. 2020). Living specimens were illustrated and examined by Cachon & Cachon (1985: 284) and Nakamura et al. (2020: figs 2.D-2.F). The overall appearance of Thalassothamnus somewhat resembles that of the family Astracanthidae of Phaeodaria (Cercozoa, Rhizaria).However, this genus differs from the aforementioned phaeodarians in several ways: a) the cross-section of the radial spines is solid (not hollow), b) several divergent points occasionally exist, and, c) there is generally one central capsule (whereas, several central capsules can be found in Astracanthidae ).