Williriedellum occultithorax 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 : 121

Williriedellum occultithorax Dumitrică n. sp.

Figs. 10 s-s1

Description. Shell with abdomen practically spherical, smooth surfaced with dense and small circular pores arranged quincuncially. Cephalothorax with thorax hidden in the abdominal chamber. Cephalis small imperforated and thorax practically completely hidden in abdominal wall and cavity. Sutural pore not visible; it is probably situated on the other side of the shell. Aperture large, circular with rounded border.

Studied material. A single specimen in sample OZ826.

Holotype. Figs. 10 s-s1, coll. MGP-PD, stub PD120 - OZ826- R11-08 a-c.

Dimensions. Diameter of abdomen 124 µm.

Etymology. From the Latin verb occultus, - a, - um = hidden, and thorax, as the thorax is hidden in the abdomen.

Remarks. This species differs from the other syngeneric taxa by the large distal aperture with rounded borders, very small abdominal pores, smooth surface, and hidden thorax.

Occurrence. A single specimen in sample OZ826.

Figures

Fig. 10 a-c1 - Hemicryptocapsa (?) bellireticulum (Wu & Li): a - OZ825, b - OZ836. c - OZ838, c1 - OZ824. d-f, j-j2 - Williriedellum labeosum Dumitrică n. sp.: d, e, j-j2, OZ837, f - OZ834. g, g1 - Cryptamphorella circumthoracica Dumitrică n. sp., OZ838; g1 - view of apical part. h, k-o – Cryptamphorella dumitricai Schaaf: h - detail of sutural pore, k - OZ825, l - OZ 824, m - OZ838, n-o, OZ839. i, i1- Williriedellum gilkei Dumitrică, OZ838. p - Zhamoidellum ovum Dumitrică, OZ839. r - Williriedellum cordiforme Dumitrică n. sp., OZ837. s, s1 - Williriedellum occultithorax Dumitrică n. sp. in lateral and obliquely apical views, OZ826. t-t2 – Cryptamphorella crassilabrosa Dumitrică n. sp., OZ837: t, t1 - holotype in two positions, t2 – sutural pore much magnified showing inside the wall of the hidden thorax. Figs. a-f, i, h, k-o, r x250; g, gi, h, t, t1 x300.