AMPHITHOLIDAE Haeckel, 1887

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 : 448-449

Family AMPHITHOLIDAE Haeckel, 1887 n. stat.

sensu De Wever et al. (2001)

Amphitholida Haeckel, 1887: 663 [as a subfamily].

Archidiscaria Haeckel, 1887: 484 [nomen dubium, as a section between subfamily and family].

Archidiscida Haeckel, 1887: 484-485 [nomen dubium, as a subfamily]. — Schröder 1909: 42. — Chen et al. 2017: 138 [as a subfamily].

Tholonida Haeckel, 1887: 604, 660-663 [nomen dubium, as a family]. — Bütschli 1889: 1967 [as a family]. — nec Rüst 1892: 141. — Schröder 1909: 4 [as a family]. — Anderson 1983: 24 [as a family].

Staurotholida Haeckel, 1887: 663, 670 [nomen dubium, as a subfamily].

Cubotholida Haeckel, 1887: 663, 677 [as a subfamily].

Tholoniidae – Poche 1913: 210 [nomen dubium]. — Campbell 1954: D98. — Riedel 1967b: 295; 1971: 655. — Nakaseko et al. 1975: 171. — Nakaseko & Sugano 1976: 126. — Riedel & Sanfilippo 1977: 867. — Petrushevskaya 1979: 110. — Anderson 1983: 39. — Dumitrica 1984: 101. — Takahashi 1991: 89. — Chen & Tan 1996: 152. — Boltovskoy 1998: 32. — Tan 1998: 270-271. — Anderson et al. 2002: 1003. — De Wever et al. 2001: 157-158. — Afanasieva et al. 2005: S287. — Afanasieva & Amon 2006: 130. — Matsuzaki et al. 2015: 35-36.

Archidiscinae – Campbell 1954: D88 [nomen dubium]. — Chediya 1959: 132.

Amphitholinae – Campbell 1954: D98. — Chediya 1959: 156.

Staurotholinae – Campbell 1954: D98 [nomen dubium]. — Chediya 1959: 157.

Tholoniinae – Campbell 1954: D98 [nomen dubium]. — Dumitrica 1989: 234, 237.

Tholonidae [sic] – Chediya 1959: 156 [nomen dubium] (= Tholoniidae ). — Tan & Su 1982: 160. — Tan & Chen 1999: 257. — Chen et al. 2017: 156.

Cubotholinae – Chediya 1959: 157.

TYPE GENUS. — Amphitholus Haeckel, 1887: 666 [type species by subsequent designation ( Campbell 1954: D98): Amphitholus artiscus Haeckel, 1887: 666 ] = junior subjective synonym of Tholomura Haeckel, 1887: 672 [type species by monotypy: Tholoma metallasson Haeckel, 1887: 672 ].

INCLUDED GENERA. — Tholomura Haeckel, 1887: 672 (= Amphitholonium , Cubotholonium , Staurotholoma synonymized by Matsuzaki et al. 2015: 36; Amphitholissa n. syn., Amphitholura n. syn., Amphitholus n. syn., Cubotholissa n. syn., Cubotholus n. syn., Staurotholura

n. syn., Tholartella n. syn., Tholartus n. syn., Tholocubitus n. syn., Tholodes n. syn., Tholocubulus n. syn., Tholocubus n. syn., Tholoma n. syn., Tholomantha n. syn., Tholonilla synonymized by Zhang & Suzuki 2017: 59 ).

INVALID NAME. — Tholothauma .

NOMINA DUBIA. — Archidiscus , Axodiscus , Circoniscus , Cubotholura , Dioniscus , Hexoniscus , Pentoniscus , Staurotholissa , Staurotholodes , Staurotholonium , Staurotholus , Tetroniscus , Tholartissa , Tholonetta , Tholonium , Tholostaurantha , Tholostauroma , Tholostaurus , Trioniscus .

DIAGNOSIS. — Phorticioidea with gates of the girdles closed by pillars in earlier ontogenetic stages, which become completely closed with growing. In latest ontogenetic stages, the cupolas becoming opposite latticed domes successively disposed on each of the three cartesian axes. Protoplasm occupies the inner space of the cortical shell. No algal symbionts are detected. A gelatinous sheath wraps the entirety of shell, including the lower part of the radial spines.

STRATIGRAPHIC OCCURRENCE. — Holocene-Living.

REMARKS

The reason of the synonymy with Tholomura was explained in detail by Matsuzaki et al. (2015). This family was called Tholoniidae but its type genus is a nomen dubium. We selected the family name Amphitholidae due to the illustration of the Amphitholonium type species displaying a clearer internal structure than that of Cubotholonium . The internal skeletal structure for Tholomura has been already illustrated ( Dumitrica 1989: pl. 15, figs 7-10; Sugiyama et al. 1992: pl. 11, fig. 6-9). Protoplasm and algal symbionts were documented by epi-fluorescent techniques using DAPI methods ( Zhang et al. 2018: 14, fig. 30, p. 17, fig. 12).

VALIDITY OF GENERA

Tholomura

The morphological terminology followed both an anatomical terminology ( Zhang & Suzuki 2017 : tables 1-4, figs 3-5) and a morphology under a transmitted microscope ( Zhang & Suzuki 2017 : fig. 2).

It is helpful to understand the validity of the genera using the knowledge of the formation of the shell in Tholomura . The ideal Tholomura has the following structures: the “central combination” of S1a (= microsphere) and S1a-girdle in the center, the six cupolas with the settings of two opposite cupolas aligned along the three perpendicular axes outside of the “central combination”. The word “cupola” is also called “dome-shaped test”, and is defined as a large vaulted dome ( Zhang & Suzuki 2017 : table 1). These six cupolas form the 2nd pseudo-concentric shell. The term pseudo-concentric shell is defined for an easy recognition of the concentric patterns for Tholomura in transmitted light microscopy and the 2 nd pseudo-concentric shell corresponds to the anatomical term “S2-girdles”. The three sets of two opposite cupolas in the case of S2-girdels are anatomically called “G1 of S2-girdle”, “G2 of S2-girdle” and “G3 of S2-girdle from the inner one to the outer one within the S2-girdle. Outside of the 2nd pseudoconcentric shell (=S2-girdle), the next three sets of two opposite cupolas are developed as the 3rd pseudo-concentric shell (=S3-girdle). The Tholoniidae sensu Campbell (1954 : D94) are subdivided into three subfamilies based on the development patterns of cupolas: A set of two opposite cupolas are aligned along three perpendicular axes in the “Tholoniinae”, along to two perpendicular axes in the “Staurotholoninae”, and along a single axis in the “Amphitholinae”. They correspond to the presence of G3, G2 and G1 of a certain girdle, respectively. This means that the different ontogenetic stages of the same pseudo-concentric shell were separated at the subfamily level. The subfamily in the sense of Campbell (1954) was systematically divided into genera with “how many cupolas pile up?” and the existence of a medullary shell. The former reflects the number of pseudo-concentric shells and the latter is related with preservation conditions. Genera in the sense of Campbell (1954) are subdivided into subgenera with the occurrence of radial spines or thorns. Radial spines may or may not be different at species level.

The Atlas illustrated 14 available genera after exclusion of nomina dubia, junior objective synonyms and invalid names . In consideration of the definition of Campbell (1954), of the type-illustrations cited from Haeckel (1887) and our supporting image, these 14 available genera can be arranged as follows: 1) Three pseudo-concentric shells: Amphitholura , Tholartus (presumably) and Tholodes (presumably)(G1 mode); Cubotholus , Staurotholura , Tholocubitus (probably), Tholonilla (probably) (G2 mode); and 2) Four pseudo-concentric shells: Amphitholonium , Amphitholus (presumably) and Staurotholoma (G1 mode); Tholoma (presumably), Tholocubus (probably) and Tholomura (probably) (G2 mode); and Cubotholonium (G3 mode). Genera “probably” assigned here are based on supporting images of this Atlas and those “presumably” assigned here are classified on the basis of a probable existence of more internal shells from other specimens. These genera were compared under the same mode and the same number of pseudo-concentric shells and there are no significant differences within these groups. As the difference between G1, G2 and G3 is related with different ontogenetic modes under the same number of pseudo-concentric shells, this is not a criterion for genus. There are no differences among different numbers of pseudo-concentric shells so that all these 14 available genera are included in the same genus. In respect to the first formal discussion by Matsuzaki et al. (2015), Tholomura is validated among these genera that were simultaneous published in Haeckel (1887).