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Axoprunum (?) monostylum
Caulet, 1986
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Description - Add description
Axoprumun with one single strong polar spine. Three shells subspherical tu cuboid; 20-25 pores on the equatorial plane. The medullary and cortical shells are joined by rods (about 6) disposed in the equatorial plane, and by 2 rods going to the opposite poles of the shell. One rod penetrates the cortical shell and forms a strong spine, three-edged and thorny at its end. The other rod projects as a small thorn. Secondary spines, three-edged, often broken, arise from the bars of the third shell.
Dimensions:
Polar spines length, 100-120µm. Shell diameter, 80-90µm.
Remarks:
Very similar morphotypes can be found in some Langhian marls from Spain. But these older forms possess shells with 35-40 small pores. A nearly dissolved specimen was found in sample 586B-20-3,60-61cm, but it is difficult to describe with precision.Assignment of a generic nae to this morphotype poses a difficult taxonomic problem. Vinassa (1900) describes two Prunoidea and two Sphaeroidea with a single polar spine (Dorydruppa, Doryprunum and Dorysphaera, Dorylonchidium). But the descriptions are very sketchy and the figures of this species cannot be compared to this species. As the inner structure of A. monostylum seems to be similar to the inner structure of A. stauraxonium, this new morphotype is privisionally ascribed to the genus Axoprunum. | Caulet 1986 |
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