Pseudoxitus wui 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 : 151

Pseudoxitus wui Dumitrică n. sp.

Fig. 16d

Description. Shell elongate ovoid consisting of five segments. Cephalis and thorax form a conical portion of shell with smooth surface, rounded apex and without apical horn. Both chambers separated by a circumferential row of small pores. Thorax perforated by very small pores irregularly disposed. Abdomen is truncate-conical and continues the conical shell above. It is a little more expanded, has larger pores, a circumferential row of very small tubercles at the lower part and an imperforated circle at the upper part, which is connected by a rib with each of the lower tubercles forming trapezoidal areas with rather regularly disposed pores. First postabdominal segment cylindrical with much larger diameter than abdomen and with surface divided into polygonal areas by differently oriented ribs which form very small tubercles at their meeting points. Pores a little larger than those of the abdominal segment, circular and disposed in regular rows of various orientations. Postlumbar boundary more or less well marked by a constriction. Second postabdominal chamber sensibly shorter than the first postabdominal one and slightly inverted-trapezoidal in outline. Its superficial ornamentation similar to that of the first postabdominal chamber. Second postlumbar boundary marked by a circle of rare larger pores. Distal end with a large circular opening.

Studied material. The illustrated specimen and one specimen from Oman .

Holotype. Fig. 16d , coll. MGP-PD, stub PD120 -OZ838- R05-07 .

Dimensions. Length of test 180 µm, maximum diameter 104 µm.

Etymology. The species is dedicated to Haoruo Wu who described several species of the family Xitidae .

Remarks. Pseudoxitus wui n. sp. seems to belong to a small group of species with ovoid shell formed of five segments and having tuberculate surface such as Pseudoxitus seriola Dumitrică and P. laguncula Dumitrică. Pseudoxitus wui differs from the other species mentioned in this genus by lacking big tubercles but by having polygonal areas outlined by thin crests and very small tubercles at the meeting points of crests.

Range and occurrence. Upper Valanginian of Sardinia to Hauterivian of Oman.

Figures

Fig. 16 a, b, m, n - Novixitus quadripartitus Dumitrică n. sp.: a - holotype, OZ836. b - paratype, OZ834. c?, g-i, k, l, - Novixitus robustus Wu, OZ825. d - Pseudoxitus wui Dumitrică n. sp., holotype, OZ836. e - Xitus vermiculatus (Renz), OZ838. f, j - Pseudoxitus laguncula Dumitrică, OZ836. i - OZ836, k - basal view, OZ839. All figures x250.