Toritenum hirsutum, Dumitrica & Zügel, 2003

Dumitrica, Paulian & Zügel, Peter, 2003, Lower Tithonian mono- and dicyrtid Nassellaria (Radiolaria) from the Solnhofen area (southern Germany), Geodiversitas 25 (1), pp. 5-72 : 52

Toritenum hirsutum n. sp. ( Fig. 26 A-C, H)

Parvicingula sp. aff. P.(?) obesa – Hattori 1989: 89, pl. 44, fig. F.

HOLOTYPE. — Photo No. 45636; stub Mue 22/ 16; Musée de Géologie , Lausanne, No. 74406 ( Fig. 26A ).

ETYMOLOGY. — From the Latin hirsutus: hirsute, hairy.

OCCURENCE. — Early Middle Jurassic of Japan ( Hattori 1989), early Tithonian ( Hybonotum Zone ).

MATERIAL EXAMINED. — 15 illustrated specimens and many others not illustrated from the type horizon (sample Mue 22).

DIMENSIONS ( IN µM). — Total length 465-560 (av. 505), length of apical horn 90-120 (av. 105), width of cephalis measured on the first circumferential ridge 75- 120 (av. 95), maximum width of test 200-265 (av. 225). DESCRIPTION

Test highly conical composed of a short conical cephalis and a very long conical to cylindrical thorax. Cephalis with small pores distributed irregularly and a long, robust three-bladed apical horn in axial position. Transition between cephalis and apical horn gradual in both outline and superficial ornamentation, longitudinal ridges on the cephalis coalescing gradually on the blades of the horn. Collar boundary marked by a circumferential ridge. V, D, and the two L shortly prolonged on the inner surface of thorax but not visible on the outer surface. Proximal part of thorax rapidly increasing in diametre, middle and distal parts commonly cylindrical or even slightly tapering distally. Thorax usually with seven to 10 or more circumferential ridges separated by concave bands. Ridges on proximal part usually rather close to each other, with two to four transverse rows of alternate pores between two ridges. Median and distal parts with larger intervals between ridges, which may have seven to 10 transverse rows of alternate pores. Pores small and rounded. Cephalis and proximal part of thorax, especially, covered by numerous small thorns, size and frequency of thorns decreasing distally.

REMARKS

Toritenum hirsutum n. gen., n. sp. is the most frequent species of this family in the sample Mue 22, outnumbering by 10 times the total number of specimens of the other species. The specimen illustrated by Hattori (1989) is quite probably the oldest representative of this species. It only differs from our specimens in not having small thorns on cephalis and proximal part of thorax. The species illustrated by Kiessling (1999) as Eucyrtidium (?) sp. differs from T. hirsutum n. gen., n. sp. in being higher-conical.

Figures

FIG. 26. — A-C, H, Toritenum hirsutum n. gen., n. sp.; A, holotype; B, C, H, paratypes; C, broken specimen showing non-segmented internal surface; H, broken specimen, basal view showing details of initial spicule; D-G, Toritenum corpulentum n. gen., n. sp.; D, holotype; E-G, paratypes. Scale bars: A-G, 100 µm; H, 30 µm.