Trimanicula centrospina Dumitrică, 1991

Dumitrica, Paulian, 2019, Cenozoic Spumellarian Radiolaria With Eccentric Microsphere, Acta Palaeontologica Romaniae 15 (1), pp. 39-60 : 47-48

Trimanicula centrospina Dumitrică, 1991

Figures 7a, f

1972 Trigonactinium sp. – Petrushevskaya & Kozlova, pl. 17, fig. 2.

1987 Suttonium sp. – Petrushevskaya, p. 1451, fig. 4 (9- 10).

1991 Trimanicula centrospina Dumitrică , p. 52, pl. 3, fig. 4; pl. 4, figs. 1, 3, 4; pl. 7, figs. 8-10; pl. 8, figs. 1-6, 9-11; pl. 9, figs. 1-10.

2001 Trimanicula centrospina Dumitrică – De Wever et al., p. 142-143, fig. 82. 1-2.

Remarks. Due to its range and regular three-rayed shell, this species evolved, directly or through a yet unknown intermediary species, from the early Paleocene species Trimanicula penultima Dumitrică by a slight migration of the microsphere towards the centre and, as a consequence, regularization of the skeleton that from bilaterally symmetrical and cross-shaped became regularly three radial with angles of about 120° between arms.

Range and occurrence. Early Oligocene to early Pliocene so far as known.

Figures

Fig. 7 a, f. Trimanicula centrospina Dumitrică, holotype rephotographed, AMPH 6P, 21-23 cm., f – same, central part of a, double magnified. b. Trimanicula penultima Dumitrică, holotype rephotographed, DSDP 21-208-31 CC. c-e – Cryptomanicula absconsa Dumitrică nov. gen., nov. sp., same, paratype as that illustrated on fig. 3h, focused at another level; d. e – detail of centre focused on surface and on microsphere, respectively, DSDP 21-208-30 CC. Scale bar of a-c = 50 μm.