- Type images:
type image: A. pyroensis
From Suzuki Paleotax db:
2015 Arachnocorallium? pyroensis n. sp. Renaudie & Lazarus p. 193, pl. 5, figs. 6A-6B, 8-9B
Catalog entries: Arachnocorallium pyroensis
type image: A. pyroensisOriginal description:
Diagnosis. Cephalis wall is a loose meshwork attached to a sagit- tal ring; spines D, Ll and Lr are long and thin.
Description. Monocyrtid with a cephalis arranged on both sides of a clearly developed sagittal ring (i.e. A, V and arch AV; see Pl. 5, fig. 9B). This sagittal ring apex is orientated ventrally. Spines D, Ll and Lr are well developed, long, thin and conical. A supplementary spine projects from spine A dorsally as a short conical horn. Ventrally, a triangular dent can be seen high on spine V. Shell wall is loose, consists of a few large, elliptical pores separated by crested bars. In apical view (see specimen Pl. 5, fig. 6A–B), the shell has a cardioid outline due to a constriction following spine A. The breadth (perpendicularly to the sagittal ring) seems on this specimen slightly greater than its width (parallel to the sagittal ring).
Remarks. Despite having what seems to be a sagittal ring, this species is unlikely to be a trissocyclid due to the absence of a basal ring. It differs from members of the genus Zygocircus Bütschli, 1882 and the genus Cortina Haeckel, 1887 in possessing a shell wall and in its well-developed spines D, Ll and Lr. It differs from members of the genus Arachnocorallium in possessing a sagittal ring. The generic assignment is therefore provisional and based on the postulate that the presence of the sagittal ring in this species is only a convergence with the sagittal ring seen in the Trissocyclidae sensu Goll (1979), the Acanthodesmiidae sensuPetrushevskaya (1971) or even the Stephaniidae sensu Nishimura (1990).
Geological Range:
Last occurrence (top): within Tortonian Stage (7.25-11.62Ma, top in Tortonian stage). Data source:
First occurrence (base): within Tortonian Stage (7.25-11.62Ma, base in Tortonian stage). Data source:
Plot of occurrence data:
References:
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Arachnocorallium pyroensis compiled by the radiolaria@mikrotax project team viewed: 20-8-2026
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