Humerocyrtis undulata, 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 : 69-70

Humerocyrtis undulata n. sp.

Figs. 8e ,?8d

Diagnosis. Shell bell-shaped and thick-walled with a three-bladed, robust, pointed and slightly curved apical horn. One of its blades is in the plane of the ventral spine and the other two are laterally directed. Ventral spine very short and pointed. Cephalis cavity pear-shaped with pointed end in apical direction and its wall practically poreless. Collar boundary marked by a slight constriction and by the appearance of pores. Thorax short, thick-walled, with evident shoulder but without a circumferential ring. Distal end thick with undulate border. Pores of thorax rounded, separated by wide intervening bars and relatively quincuncially arranged.

Studied material. Two specimens in sample Rc4.

Holotype. Fig. 8e , coll. MGL.110291.

Paratype. Fig. 8d , coll. MGL .110292.

Dimensions. Length of shell with apical horn 120-140 µm, of apical horn 40-65 µm, length of cephalis 25-30 µm, of thorax 50-55 µm, diameter of shoulder 60-64 µm, of distal end 72-?95 µm.

Etymology. From the Latin undulatus, - a, - um – winding due to its undulate distal border.

Remarks. This species differs from the other species of this genus herein described by the undulate distal border. The specimen illustrated in Fig. 8d is questionably included in this species because its thorax is less thick, the shoulder less marked and the distal end less undulated. By its overall morphology it seems to be intermediate between H. undulata and H. gracilis n. sp.

Stratigraphic range. Sparse in Buchenstein Formation, lower Ladinian, Recoaro.

Figures

Fig. 8. a. – Humerocyrtis contraria n. sp., holotype, Rc4; b. – Humerocyrtis conica n. sp., holotype, Rc4. c. – Humerocyrtis jekeli n. sp., holotype, Rc2; e,?d.– Humerocyrtis undulata n. sp., Rc4: e – holotype. f – Humerocyrtis lahmi n. sp., holotype, Rc4. Scale bar of 50 µm is for all figures.