HOLLANDOSPHAERIDAE Deflandre, 1973

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 : 417-418

Family HOLLANDOSPHAERIDAE Deflandre, 1973

Hollandosphaeridae Deflandre, 1973: 1151 . — Cachon & Cachon 1985: 288.

Coscinommida Haeckel, 1887: 208 [nomen dubium, as a subfamily]. — Wisniowski 1889: 684 [as a subfamily]. — Schröder 1909: 16 [as a subfamily].

Coscinomminae – Campbell & Clark 1944a: 15 [nomen dubium]. — Clark & Campbell 1945: 16. — Chediya 1959: 94.

Heliasteridae Hollande & Enjumet, 1960: 68 , 86, 91 [unavailable name] (= Hollandosphaeridae ). — Anderson 1983: 50.

TYPE GENUS. — Hollandosphaera Deflandre, 1973: 1150 [type species by monotypy; ICZN 1999: art. 67.8: Heliaster hexagonium Hollande & Enjumet, 1960: 92 ].

INCLUDED GENERA. — Anomalosoma Loeblich & Tappan, 1961: 223. — Hollandosphaera Deflandre, 1973: 1150 . — Tetrapetalon Hollande & Enjumet, 1960: 92 .

NOMINA DUBIA. — Coscinomma , Coscinommarium , Coscinommidium , Coscinommonium .

JUNIOR HOMONYMS. — Heterosoma Hollande & Enjumet, 1960 (= Anomalosoma) nec Schaum, 1845; Heliaster Hollande & Enjumet, 1960 (= Hollandosphaera ) nec Gray, 1840.

DIAGNOSIS. — One spherical shell with a honeycomb structure and fine internal spicules originating in a center. Architecture of fine internal spicules are variable among genera. Many by-spines or more than eight fine radial spines are present. Neither robust radial beams or spines are present.

As for Hollandosphaera , a reddish endoplasm occupies a large portion inside the cortical shell. Hundreds of algal symbionts are scattered along important pseudopodia which radiate throughout the shell. A straight robust axoflagellum appears. Tetrapetalon also possesses algal symbionts. In the axopodial system of periaxoplastid-type: the axoplast is located outside of the nucleus and is attached on a side of the nucleus. Axonemes cross the nucleus through nucleus membrane tunnels and form a thick bundle of axonemes in the intracapsular zone. This thick bundle forms an axoflagellum. The axoplast either encloses the Median Bar (MB) or a relevant structure of the initial spicular system. Conversely, it may be attached on MB or a relevant structure. The nucleus is situated inside the central structure or encloses it. Bundles of axonemes extend to the opposite side of MB or a relevant structure.

STRATIGRAPHIC OCCURRENCE. — Holocene-Living.

REMARKS

A precise determination of Hollandosphaeridae relies on the internal structure, but the honeycomb structure of the spherical shell is useful in specifying possible Hollandosphaeridaetaxa. The shell is so fragile that reliable fossil records have not been reported yet. Classical representatives of Cenosphaera and Acanthosphaera , currently Ethmosphaera ( Ethmosphaeridae ) and Rhaphidocapsa (Actinommidae) in the catalogue, may be mixed with members of Hollandosphaeridae (see remarks for Actinommidae ). Internal skeletal structure is illustrated for Hollandosphaera ( van de Paverd 1995: pl. 20, fig. 1; Onodera et al. 2011: pl. 3, fig. 3). Living or protoplasmic image was published for Hollandosphaera ( Probert et al. 2014: S1, Vil 217, S2, VER 1; Suzuki & Not 2015: fig. 8.8.9) and Tetrapetalon (Anderson et al. 1998: pl. 1, fig.1). Fine protoplasmic structure is illustrated for Hollandosphaera ( Hollande & Enjumet 1960: pl. 2, figs 5-8; pl. 6, fig. 11; pl. 7, fig. 6; pl. 39, figs 1-5; pl. 41, figs 1, 2) and Tetrapetalon ( Hollande & Enjumet 1960: pl. 1, fig. 10; pl. 41, fig. 4; Anderson et al. 1998: pls 1, 2). Some genera may not have been formally described yet (e.g., Itaki et al. 2012: pl. 2, fig. 3). Algal symbionts of Hollandosphaera are identified as Brandtodinium nutricula by Probert et al. (2014).