Archaeodictyomitra pumila Dumitrică, 2022

Dumitrica, Paulian, Dieni, Iginio & Massari, Francesco, 2022, Valanginian Radiolarians Of Ne Sardinia (Italy) In The Frame Of The Weissert Event, Acta Palaeontologica Romaniae 18 (2), pp. 97-159 : 141

Archaeodictyomitra pumila Dumitrică n. sp.

Fig. 14c

Description. Shell very small conical with nine continuous costae visible on half the perimeter in lateral view. Pores circular, increasing in size distally and arranged in two rows on each segment: one above the segment junctions and one below, separated by a wide imperforate transversal band in the middle of segments. Segmental junction marked by a narrow band between the two rows of pores, one corresponding to the anterior chamber and one to the posterior chamber. Distal end without the appendage characteristic of Thanarla . Distal end opend in a large circular aperture.

Studied material. A single specimen in sample OZ834.

Holotype. Fig. 14c , coll. MGP-PD, stub PD120 -OZ834- R09-12 .

Dimensions. Length 122 µm, maximum diameter 70 µm.

Etymology. From the Latin pumilus, - a, -um = dwarf.

Remarks. By its conical shape, this species has the morphology of the genus Thanarla and the wall with pore disposition as in Apiaromitra n. gen.

Occurrence. A single specimen in the upper Valanginian sample OZ 834.

Figures

Fig. 14 a - Archaeodictyomitra conicoscalaris Dumitrică n. sp., OZ839. b, f - Archaeodictyomitra humerosa Dumitrică n. sp.: b - OZ834, f - OZ824. c - Archaeodictyomitra pumila Dumitrică n. sp., OZ834. d, e - Archaeodictyomitra conica (Aliev), OZ824. g - Thanarla cf. pulchra (Squinabol), OZ825. h - Thanarla pulchra (Squinabol), OZ839. i, j – Mictyoditra thiensis (Tan), OZ836. k - Archaeodictyomitra excellens (Tan), OZ839. l - Archaeodictyomitra sp., OZ836. m, n - Loopus nudus (Schaaf): m - OZ838, n - OZ834. o - Loopus cf. primitivus (Matsuoka & Yao), OZ834. p, p1, p2 - Svinitzium depressum (Baumgartner), p1, p2 - details of penultimate segmental band showing relic pores of parvicingulid type or other types, OZ824. Figs. r, t - Svinitzium (?) irregulare Dumitrică n. sp.: r - OZ 836, t - OZ834. s, u - Pseudodictyomitra cf. carpatica (Lozynyak): s - OZ834, u - OZ 824. Figs. b, n x250, the others x300.