Trimanicula penultima Dumitrică, 1991

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

Trimanicula penultima Dumitrică, 1991

Figure 7b

1991 Trimanicula penultima Dumitrică, 1991, p. 54 , pl. 3, fig. 5; pl. 4, fig. 2; pl. 8, figs. 7, 8; pl. 9, figs. 11-13.

Remarks. The species is very rare, represented until present by only the holotype. It evolved probably from the genus Patulibracchium Pessagno , its probable forerunner, by the reduction of the arms probably during the Cretaceous-Tertiary boundary crisis. Judging from the morphology of the holotype, it seems that it is a young specimen with the arms incompletely developed. This holotype differs from T. centrospina Dumitrică especially by the angle between the lateral primary rays that reaches 160°, rather close to that of some Campanian species of the genus Patulibracchium illustrated by Pessagno (1971).

Range and occurrence. Earliest Paleocene, DSDP 21- 208-31 CC, Lord Howe Rise, SW Pacific.

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.