Humerocyrtis marmoladensis, Dumitrică, 2024

Dumitrică, Paulian, 2024, New Middle Triassic Bell-Shaped Nassellarian Radiolaria From Alpine And Carpathian Areas, Acta Palaeontologica Romaniae 20 (1), pp. 51-75 : 74

Humerocyrtis marmoladensis n. sp.

Fig. 10f

Diagnosis. Shell bell-shaped, wide opened distally with cephalis bearing a long, straight and thin conical apical horn in axial position and a three-bladed ventral spine with thin but very broad triangular blades. Cephalis elongate globular and practically imperforated except its distal part that contained small and irregularly disposed pores. Its distal end passes gradually to the short and wide conical proximal part of thorax. Shoulder rather angular but without a circumferential ridge. Distal part of thorax wide open, slightly concave; distal end of shell irregular and of diameter larger than that of the shoulder.

Studied material. The holotype from the sample BV 85- 70.

Holotype. Figure 10f , coll. MGL.110301.

Dimensions. Length of shell without apical horn 108 µm, of apical horn 67 µm, of ventral horn 42 µm, diameter of shoulder 75 µm, of distal end 97 µm.

Etymology. From the Marmolada Massif, north Italy.

Remarks. The shape of the shell of Humerocyrtis marmoladensis n. sp. resembles very well that of the species Humerocyrtis gracilis n. sp., from which it differs by having larger and irregularly arranged pores, a very long and thin conical apical horn and the ventral horn thick, three-bladed and much longer.

Stratigraphic range. Very rare in the lower Ladinian of the Livinallongo Formation, Marmolada Massif, North Italy.

Figures

Fig. 10. a – Humerocyrtis infinita n. sp, Rc4. b, d – Humerocyrtis brevithorax n. sp.: b – R78/1b, d – poorly preserved specimen, Rc4. c – Humerocyrtis asymmetrica n. sp., Rc4. f – Humerocyrtis marmoladensis n. sp., BV 85-70. e, g – Humerocyrtis mediotriassica n. sp.: e – CR25, g – Rc4. Scale bar of 50 µm is for all figures.