Alievium rotundum 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 : 112

Alievium rotundum Dumitrică n. sp.

Fig. 8h, i, k, l

Description. Shell circular or subcircular in face view with 3 three-bladed equatorial spines of unknown length. Structurally, shell consists exclusively of an equal triangular meshwork of thin bars interconnecting relatively thick nodes. Usually this triangular meshwork is complicated by development of very thin bars interconnecting the primary bars. Nodes not prolonged into spines but arranged in commonly straight parallel rows, the maximum number of nodes on rows varying between 6-7.

Studied materials. Eight specimens.

Holotype. Figure 8 k, l , coll. MGP-PD, stub PD120 - OZ834- R10-28 .

Dimensions. Diameter of shell 160-200 µm.

Etymology. From the Latin rotundus, - a, - um – round, circular.

Remarks. This species is the most common pseudoaulophacid in the Valanginian radiolarian fauna from Sardinia. It differs from Alievium regulare , as it is understood in the present article, by having larger size, more shell layers and by not having spines originated on tubercles. Fig. 8h is a broken specimen of probably A. rotundum showing the internal skeleton.

Occurrence. Upper Valanginian in Sardinia so far as known .

Figures

Fig. 8. a - Becus coronatus Dumitrică n. sp., OZ839. b-f1, j - Becus triangulocentrum Dumitrică, b - OZ836; c - same, lateral view, d - OZ836. e, f - OZ825, f1 - lateral view of fig. f. g - Alievium regulare (Wu & Li), OZ836. h, i, k, l - Alievium rotundum Dumitrică n. sp.: h, specimen destroyed showing internal structure, OZ836; i - OZ836, k, l - holotype, OZ834. m - Alievium incomptum Dumitrică n. sp., OZ836. n - Godia (?) lenticulata Dumitrică n. sp., OZ834. o - Godia (?) lens Dumitrică n. sp., OZ825. p - Alievium eurasicum Dumitrică n. sp., OZ825. r - Microsandwichia plana (Hori), OZ834. s, t - Spumellarian gen. et sp. indet., OZ834. figs. c, e-h, k, m, r, t x250, figs. a, b, d, i, j, l, p, s x300; figs. n, o, t x400.