TRIPODISCIIDAE Haeckel, 1882

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 : 508

Family TRIPODISCIIDAE Haeckel, 1882 n. stat.

Tripodiscida Haeckel, 1882: 428 [below tribe].

TYPE GENUS. — Tripodiscium Haeckel, 1882: 427 [type species by subsequent designation ( Campbell 1954: D117): Tripodiscium tristylospyris Haeckel, 1887: 1143 ].

INCLUDED GENERA. — Tridictyopus Hertwig, 1879: 203. — Tripodiscium Haeckel, 1882: 427 (= Tripodiscinus with the same type species; Tripodisculus n. syn., Tristylospyrium n. syn.). —? Tristylocorys Haeckel, 1887: 1140 .

DIAGNOSIS. — One segment with three feet and no apical horn.

STRATIGRAPHIC OCCURRENCE. — Living.

REMARKS

This family is simply used to maintain Tripodiscium as a valid genus in this review; however, the consistency of Tripodisciidae needs to be confirmed by retrieving good specimens of the genera included in this family. Tridictyopus is very similar to Conicavus . Broken specimen of Periplecta (Phaenocalpididae) and the Tripocyrtis -form of Clathrocanium (Sethoperidae) are nearly identical to Tripodiscium .

VALIDITY OF GENERA

Tripodiscium

Although the type-illustrations of Tripodiscium ( Haeckel 1887: pl. 52, fig. 22), Tripodisculus ( Haeckel 1887: pl. 52, fig. 21), and Tristylospyrium ( Haeckel 1887: pl. 52, fig. 23) are very similar, Campbell (1954) placed these genera within different superfamilies. Tristylospyrium was classified into “ Triospyridinae of the Triospyrididae within superfamily Triospyridicae ” ( Campbell 1954: D112), whereas Tripodiscium and Tripodisculus were classified into “Archipiliinae of the Archipiliidae within subsuperfamily Archipiliilae within superfamily Archipiliicae ” ( Campbell 1954: D117). Superfamily “ Triospyridicae ” is defined by a bilocular cephalis with sagittal constriction, whereas superfamily “ Archipiliicae ” is defined by a cephalis that is neither bilocular nor lobate; these morphological characters cannot be specified in the type-illustrations. Triospyrididae is defined by a shell composed of cephalis and its apophyses, without apical cupola or dome or thorax, but this definition is applicable to Tristylospyrium , Tripodiscium , and Tripodisculus . Strangely, “three basal feet” is used to identify the subfamily Triospyridinae but also to distinguish among different ranks within family Archipiliidae . Thus, these taxonomic ranks are meaningless among Tristylospyrium , Tripodiscium , and Tripodisculus . Subfamily “Archipiliinae” within family Archipiliidae is defined as having the basal shell mouth open, which is not included as a character for subfamily “Triopsyridinae” of the Triospyrididae in the superfamily “ Triospyridicae ”, which represents another direct contradiction. Differences among these three genera are definitely not related at the family or higher taxonomic rank; therefore, it is sufficient to consider their morphological characters directly at the genus level, even sensu Campbell (1954) . Tristylospyrium is characterized by an apex without a horn, Tripodiscium by three unbranched solid feet, and Tripodisculus by branched or forked feet ( Campbell 1954: D112, 117, and 118). However, the type-illustration of Tripodiscium has branched or forked feet, not unbranched solid feet ( Haeckel 1887: pl. 52, fig. 22). Because the apex without horn and branched or forked feet are the only common features among these three genera, they need not be separated at the superfamily level. The oldest available name is Tripodiscium .