Humerocyrtis deweveri, 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 : 66-67

Humerocyrtis deweveri n. sp.

Fig. 6e

Diagnosis. Shell relatively large, bell-shaped with rounded shoulder. Proximal part, consisting of cephalis and upper part of thorax, conical with concave lateral sides. Cephalis conical with two three-bladed horns: an apical horn in axial position and a smaller ventral horn, both pointed and having thin blades. Cephalic wall perforated by small circular or subcircular and irregularly arranged pores. Thorax of this part of shell wide conical. It has much larger and irregularly disposed pores. Shoulder rounded and having small pores of variable sizes and irregular arrangement, especially on the proximal side. On distal side of thorax the shoulder has two circumferential rows of rounded pores of various sizes. Below them the thorax is constricted and distally flared, bearing three circumferential rows of large pores arranged into 3 circumferential intercalary rows of two types: the first two rows with very large rounded rectangular or oval pores with long axes longitudinally positioned, the last row with slightly smaller pores arranged with transversally directed long axes, each row containing 6-7 pores on half the perimeter.

Studied material. A single specimen in the sample BV 85-70.

Holotype. Fig. 6e , sample BV 85-70, coll. MGL.110285.

Dimensions. Length of shell without apical horn 114 µm, with apical horn 160 µm, length of shell up to the circumferential ring 50 µm, of distal part 65 µm, diameter of cephalis 40 µm, of shoulder or circumferential ring 74 µm, of distal end 120 µm.

Etymology. The species is dedicated to my friend Prof. Patrick De Wever for his contribution to the knowledge of Triassic radiolarians.

Remarks. This new species resembles very much the species Humerocyrtis superba n. sp. by having a rather similar morphology from which it differs by being smaller, by having smaller horns, shoulder with rounded outline and distal part of thorax with only three circumferential rows of large pores.

Stratigraphic range. Livinallongo Formation, Marmolada Massif, North Italy, sample BV85-70, lower Ladinian.

Figures

Fig. 6. a, b. – Gorispela (?) triangulocephalis n. sp., FÖ 87: a. – specimen showing internal structure, b. – holotype, D – dorsal ray. c. – Humerocyrtis superba n. sp., holotype, BV 85-70; 6d, 6c. – Humerocyrtis jekeli n. sp., Rc4, 6c. – holotype, d. - paratype; e. – Humerocyrtis deweveri n. sp., holotype, BW 85-70; f. – Humerocyrtis problematica n. sp., holotype, Rc4. Scale bar of 50 µm is for all figures.