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Lophophaena(?) thaumasia Caulet, 1991

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Description. Two-segmented shell. Cephalis small, with two small dorso-lateral lobes, largely coalesced with the thorax. Apical spine included in the cephalic wall, protruding as a strong three-bladed apical horn as long as the cephalis. Vertical spine short, prolonged into an external, strong vertical spine, three-bladed. Lateral and dorsal spines extending briefly through the upper part of the thoracic wall. Collar stricture not marked. Pores subcircular, of various sizes, in irregular order. Termination ragged.
Remarks. Assignment of this species to the genus Lophophaena is not entirely satisfying. Like all Lophophaena species, its cephalis has a small ovoid shape with slightly marked dorso-lateral lobes that coalesce with the upper part of the thorax. However, the apical horn and the vertical spine are well-developed, like those of Lithomelissa and Psilomelissa representatives, but the cephalis is smaller, and lateral and dorsal spines do not protrude as external spines or feet.
Name. Thaumasia (Greek: peculiar).
Occurrences. The FCO is in Sample 119-744A-12H-3, 53-55 cm (Oligocene/Miocene boundary). The LCO is unknown. Rare to common.
Dimensions. Length of the apical horn: 30-40 µm; of the vertical spine: 20 µm; of the cephalis: 30-40 µm; of the thorax: 95-100 µm.
Maximum breadth of the cephalis: 45-55 µm; of the thorax: 100-105 µm.
Types. Holotype (MNHN no. F61384), Sample 119-744A-12H-3, 53- 55 cm, 1-Z26 (PI. 2, Fig. 5). Paratypes (MNHN no. F61385 and MNHN no. F61386), Samples 119-744A-12H-3, 53-55 cm, 1-T41/3 (PI. 2, Fig. 6), and 29-278-33-6, 48-52 cm, 3-G43.
Caulet 1991











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