Alievium eurasicum 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 : 110

Alievium eurasicum Dumitrică n. sp.

Fig. 8p

1982 Alievium sp. – Okamura & Uto, pl. 5, fig. 10.

Description. Shell lenticular in lateral view and triangular with unequal sides in face view with three long primary spines with circular cross section. Surface of shell with numerous small triangular meshes with small nodes at cross meeting points of the network. Scattered on the surface there are also some rare bigger nodes.

Studied material. A single specimen in sample OZ825.

Holotype. Fig, 8p, coll. MGP-PD, stub PD120 -OZ825- R12-11 .

Dimensions. Height 135-136 µm.

Remarks. This species, of which we have only the illustrated specimen with the three spines broken off, seems to be close to the early Cenomanian Alievium antiguum Pessagno by having the same morphology, with very small and irregularly arranged triangular meshes and many superficial nodes. However, it differs from Pessagno’s species by having some bigger nodes prolonged into very short spines and the three main spines are conical instead of three-bladed. The remain of one spine of the holotype proves that its section is circular similar to the specimen from Japan. By having three conical spines and some bigger nodes irregularly scattered on the surface of shell, it resembles perfectly the specimen illustrated by Okamura & Uto ( 1982) from the Lower Cretaceous sequence of chert in the Yokonami Mélange of Shimanto Belt, Shikoku, Japan.

This species differs especially from the other species of the Lower Cretaceous genus Alievium by having nonbladed primars spines.

Etymology. From its occurrence in Europe and Asia.

Range and occurrence. Very rarely in the upper Valanginian of Sardinia and Japan.

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.