PSEUDODICTYOPHIMIDAE Suzuki, 2021

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 : 507-508

Family PSEUDODICTYOPHIMIDAE Suzuki , n. fam.

urn:lsid:zoobank.org:act:B6589535-06A6-4E0B-84A1-7F4EC54DB8F2

Tripocalpida Haeckel, 1882: 428 [nomen dubium, below tribe]; 1887: 1133-1135 [as a family]. — Wisniowski 1889: 686 [as a family]. — Bütschli 1889: 1983 [as a family]. — nec Rüst 1892: 178 [as a family]. — nec Cayeux 1894: 206, 2111.

Tripocalpidae – Popofsky 1908: 271 [nomen dubium]; 1913: 327. — Schröder 1914: 91. — Clark & Campbell 1942: 62; 1945: 33. — Campbell & Clark 1944a: 38. — Chediya 1959: 188. — Tan & Tchang 1976: 273. — Tan & Su 1982: 169. — Nishimura 1990: 107 ( sensu emend. ). — van de Paverd 1995: 212. — Chen & Tan 1996: 153. — Tan & Chen 1999: 288. — Tan & Su 2003: 113, 114. — Chen et al. 2017: 173.

Tripocalpididae – Poche 1913: 220 [nomen dubium].

TYPE GENUS. — Pseudodictyophimus Petrushevskaya, 1971a: 91 [type species by monotypy: Dictyophimus gracilipes Bailey, 1856: 4 ].

INCLUDED GENERA. —? Chitascenium Sugiyama, 1994: 4. —? Corythomelissa Campbell 1951: 529. — Pseudodictyophimus Petrushevskaya, 1971a: 91 . — Steganocubus Sugiyama, 1993: 56 (= Marimoum n. syn.). — Syscioscenium Sugiyama, 1992c: 216 . — Tripodocyrtis Funakawa, 1994: 473 .

NOMINA DUBIA. — Dictyophimus , Pterocanium , Tripocalpis, Tripodoconus , Tripodonium .

JUNIOR HOMONYM. — Sethomelissa Haeckel, 1887 (= Corythomelissa) nec Haeckel, 1882.

DIAGNOSIS. — Anatomically, Pseudodictyophimidae Suzuki , n. fam. are practically two-segmented Plagiacanthoidea with a well-developed first segment (cephalis) and a developed, sometimes lacking, second segment (thorax). A large part of the cephalis is the eucephalic lobe located between the A- and V-rods. The postcephalic lobe and antecephalic lobe are located between the lowest part of the eucephalic lobe and the middle to lower part of the thorax. The suture and boundary of the eucephalic lobe are always situated above the MB’s level. The cephalic spicular system consists of MB, A-, V-, D-, double L- and Ax-rods. The double l-rod is generally absent. The MB is very short or retrogrades to become a pointed connection (PC) with the D- and double L-rods. The PC (or MB) is located at the center of the cephalic cavity. The V-rod is rarely absent at the genus or species levels. An anatomical basal ring composed of LL- and double AL- (or AD-) arches is present. All these arches convex upward to form a suture between the cephalis and the thorax. A large part of LL- and double AL- (or AD-) arches merges with the shell wall or is located very close to the shell wall. The Ax-rod is very short. No tubes are present on the cephalis. The feet that are directly connected to the D- and double L-rods may be present. The A-rod is merged to the cephalis. The cephalis may also be partly or fully free in the cephalic cavity. The sutures and the most constricted part of the shell are always located above the MB or PC.

A protoplasm was observed in Pseudodictyophimus . The endoplasm is transparent and located inside the cephalis. Depending on specimens, the endoplasm may also be observed in part of the thorax. No algal symbionts are observed. No axopodial projection has been found as of yet.

STRATIGRAPHIC OCCURRENCE. — Late Eocene-Living.

REMARKS

The diagnosis given above excludes Steganocubus as this genus possesses a typical, but very small basal ring-like structure and does not have three feet. Poor development of connecting bars between the basal ring-like structure and shell wall in Steganocubus seem to regard it as an intermediate form, between the Dictyocryphalidae Suzuki , n. fam. and the Pseudodictyophimidae Suzuki , n. fam. The Pseudodictyophimidae Suzuki , n. fam. is distinguished from the Dictyocryphalidae Suzuki , n. fam. by the presence of an anatomical basal ring with the LL- and double AL-arches, instead of a basal ringlike structure.

Differing from the Dimelissidae , no true arches directly connected to the D-rod exist. The overall appearance of Steganocubus is almost identical to Syscioscenium . However, the former possesses a typical but very small, basal ring-like structure whereas the latter develops LL- and double ADarches that merge with the shell wall. Both Chitascenium and Corythomelissa are difficult to distinguish from Archipilium ( Archipiliidae ), several genera belonging to the Phaenocalpididae , some genera in the Dimelissidae , and the Tripocyrtis - form of Clathrocanium (Sethoperidae) . Sandin et al. (2019) considered Chitascenium a member of the Archipiliidae . The Phaenocalpididae can be distinguished from Chitascenium and Corythomelissa by the presence of a suture with the ADarch, a well-developed ventral spine and a true basal ring. The Dimelissidae differ from both these genera by the absence of the cephalic lobe, the eccentric position of the PC or short MB, the presence of a double LV-arch. The Tripocyrtis -form of Clathrocanium differs from Chitascenium and Corythomelissa by the presence of a true basal ring, several free arches in the cephalic cavity, no sutures related to the arches, and a very small ventral tube.

The stratigraphic distribution of species belonging to Pseudodictyophimidae Suzuki , n. fam. is poorly documented; in addition, many genera and species remain undescribed. The cephalic initial spicular system is documented for Chitascenium ( Sugiyama 1994: pl. 1, figs 4, 6), Corythomelissa ( Funakawa 1994: fig. 14.1), Pseudodictyophimus ( Caulet 1974: pl. 5, figs 3-6; Poluzzi 1982: pl. 24, fig. 9?; Nishimura 1990: fig. 16.6-16.10, 18.5; Sugiyama et al. 1992: pl. 17, figs 2-4; Sugiyama 1993: fig. 23.3; Funakawa 1994: figs 12.1-12.3; 1995a: pl. 6, figs 1-2?, pl. 7, figs 2, 3, pl. 8, figs 1-6), Syscioscenium ( Sugiyama 1992c: pl. 21, figs 1-4, pl. 22, figs 1-4; 1994: pl. 1, fig. 5), Steganocubus ( Sugiyama 1992a: pl. 1, fig. 3?; 1993: figs 10-12; Funakawa 1994: figs 9.1-9.4; 1995a: pl. 9, figs 1-7, pl. 10, figs 1-4), and Tripodocyrtis ( Nishimura 1990: fig.17.7; Funakawa 1994: figs 13.1, 13.2;1995a: pl. 10, figs 5, 6). “Living” or protoplasm images are illustrated for Pseudodictyophimus ( Sashida & Uematsu 1994: fig. 3.6; Sashida & Kurihara 1999: fig. 11.5; Suzuki & Not 2015: fig. 8.11.7; Zhang et al. 2018: 19, fig. 19, p. 23, fig. 14).

VALIDITY OF GENERA Steganocubus After these genera were published, the authors who named Steganocubus and Marimoum agree that these are the same genus (interview from Funakawa and Sugiyama by NS in 1995). The name Steganocubus is older than Marimoum .