LAMPROMITRIDAE 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 : 477-478

? Family LAMPROMITRIDAE Haeckel, 1882

sensu Suzuki emend. herein

Lampromitria Haeckel, 1882: 431 [below tribe].

Lampromitridae – Petrushevskaya & Kozlova 1972: 534 ( sensu emend. ). — Petrushevskaya 1975: 589; 1981: 103. — Kozlova 1999: 113. — Amon 2000: 59. — Afanasieva et al. 2005: S295. — Afanasieva & Amon 2006: 143.

Lampromitrinae – Petrushevskaya 1981: 103-104; 1986: 134. — Amon 2000: 59-60. — Afanasieva et al. 2005: 295. — Afanasieva & Amon 2006: 143.

TYPE GENUS. — Lampromitra Haeckel, 1882: 431 [type species by subsequent designation ( Campbell 1954: D122): Lampromitra coronata Haeckel, 1887: 1214 ].

INCLUDED GENERA. — Lamprodiscus Ehrenberg, 1861b: 831 . — Lampromitra Haeckel, 1882: 431 (= Hexaphormis , Pentaphormis synonymized by Petrushevskaya 1971a: 103).

INVALID NAME. — Heptaphormis.

DIAGNOSIS. — Lampromitridae consists of a shallow hat-like conical shape formed by the cephalis and thorax. The cephalis is, small, perforated and smoothly adjoined to the thorax.No feet and no apical horn are present. The thoracic pores are systematically distributed in both longitudinal and lateral directions. A velum or velum-like structure develops in some members. The cephalis consists of a initial spicular system with A-, V-, D-, double L- and Ax-rods. The MB is either short or pointed. Both, double l-rods and a basal ring are absent. Instead of a basal ring, double AL-, double AD-, and double VL-arches develop to form a suture between the cephalis and the thorax. These are almost completely merged, forming parts of the pore frames. Direct rods from D- and double L-rods extend downward and are merged with the thoracic wall at certain points to form significant rims. The endoplasm is too small to be visible around the cephalis. Single very long robust pseudopodium (axial projection) are absent.

STRATIGRAPHIC OCCURRENCE. — Early Pliocene-Living.

REMARKS

As subsequently explained, the cephalic structure of Lamprodiscus is completely different from that of Lampromitra , ergo the diagnosis shown above is based upon Lampromitra . The taxonomic relationship between the Lampromitridae and Plectopyramididae is highly questionable due to the lack of molecular support data. Furthermore, the overall appearance and ecology of the Lampromitridae are quite different from that of the Plectopyramididae . Petrushevskaya (1981: 102) placed the Lampromitridae in the Plectopyramidoidea (originally Acropyramidoidea). Lampromitra was later placed in the Pseudodictyophimidae Suzuki , n. fam. (originally Lophophaenidae ) by De Wever et al. (2001: 226). Lamprodiscus was not treated in De Wever et al. (2001). We simply pursued the approach of Petrushevskaya (1981).

As mentioned, the cephalic structure is different between Lamprodiscus ( Nishimura 1990: figs 19.2, 19.3; Sugiyama et al. 1992: pl. 16, fig. 2) and Lampromitra ( Nishimura 1990: figs 19.1, 19.6). In Lamprodiscus , the cephalic initial spicular system consists of A-, D-, double L- and Ax-rods. The MB is pointed or very short.The V-rod may be present or absent.Both, double l-rods and basal rings are absent. Instead of a basal ring, a basal ring-like structure is present above MB or the relevant structure. The former structure is directly connected to the supplementary rods arising from the D- and double L-rods, forming the three collar-like pores of the MB. This basal ringlike structure is completely merged with the meshwork of the shell.LL-arch, or double VL-arches, develop and partially merge with a section of the cephalic meshwork.AL-arches are absent. The D- and double L-rods are subdivided at some points, or near their ends. D- and double L-rods extend downward and merge with the thoracic wall to form significant rims. The basal ring-like structure above MB is a structure unique to the Pseudodictyophimidae Suzuki , n. fam. As such, Lamprodiscus may belong to the Pseudodictyophimidae Suzuki , n. fam. Lampromitra is similar to the Theopiliidae as no basal ring is present; however, the cephalic structure is not well known, for this reason the assignation in this superfamily is queried.

The protoplasm was observed in Lamprodiscus ( Suzuki & Not 2015: fig. 8.11.20; Zhang et al. 2018: 10, figs 2.9) and Lampromitra ( Sashida & Kurihara 1999: fig. 12.13). One or two algal symbiont cells were observed several times near the cephalis in the shallow water representatives of Lamprodiscus .

Incertae familiae

INCLUDED GENUS. — Zealithapium O’Connor, 1999: 5 .

STRATIGRAPHIC OCCURRENCE. — Early Eocene-early Late Miocene.

REMARKS

Zealithapium was initially included in the Spumellaria without a clear explanation. This may be due to the lack of a recognized cephalic spicular system in the illustration of pl. 2, fig. 11 from O’Connor (1999). The proximal end of Zealithapium oamaru test shown in O’Connor (1999: pl. 2, fig. 11) is equivalent to that of other Zealithapium species of Nishimura (1990: figs 33.2-33.8). Thus, the proximal end of Zealithapium consists of MB, A, double l- and double L-rods whose structures crop out as parts of the pore meshwork. Thickness and length of both double-l and double L-rods are similar. These rods extend downward to connect with a hexagonal ring. The attachment point of these rods is always at the mid-point of the bar on the hexagonal ring. Viewed from the hexagonal ring, the MB appears to be situated in the center. The degraded cephalic spicular system is similar to that of the Plectopyramididae but other characters are dissimilar. One evolutionary hypothesis suggest that Zealithapium evolved from a spherical species with pyriform microsphere to an umbrella-type form ( Riedel & Sanfilippo 1981: 338). The forerunner belongs to Entapium ( Entapiidae , Spumellaria ), but its pear-shaped microsphere has no MB or MB-like structure.