Carpolithes sp. 3
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publication ID |
https://doi.org/ 10.37520/fi.2022.004 |
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persistent identifier |
https://treatment.plazi.org/id/039C6431-0824-FFCC-A076-949BD4A1FC4F |
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treatment provided by |
Felipe |
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scientific name |
Carpolithes sp. 3 |
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Text-fig. 8k–o View Text-fig
M a t e r i a l. One specimen, chalcedony cast, USNM
PAL 772368.
D e s c r i p t i o n. Seed, broadly ovate in lateral view, elliptic in cross section, 6.1 mm high, 6 mm in diameter perpendicular plane of symmetry and 7.5 mm parallel to it. Apex with a prominent extension, 2.7 mm in diameter and 1.5 mm in height, flared at it distal tip ( Text-fig. 8k–m View Text-fig ), with a central cylindrical aperture ( Text-fig. 8n View Text-fig ). A distinct groove runs along one side from the apical extension, down the side away from the offset, fading into the surface just before reaching the base ( Text-fig. 8k, n View Text-fig ). The surface with a very faint reticulate pattern ( Text-fig. 8l View Text-fig , lower left).
D i s c u s s i o n. We interpret this as either an anatropous seed or locule cast, possibly with an intact aril and with a prominent groove, possibly a raphe, running medially from the apex to a basal chalaza. The fact that a strong groove is not present on both sides of the seed, and that it fades towards the base, suggests that it is a raphe and not a plane of dehiscence. The prominence of the apical extension could reflect a piece of adherent seed coat, but its symmetry and the central apical canal (micropylar?) suggests a caruncle, like that of Euphorbiaceae JUSS.
The rounded base, carunculate apex, prominent raphe, and surface cellular pattern are consistent with Euphorbiaceae . It may be appropriate to place this in the fossil genus Euphorbiospermum E.REID et M.CHANDLER , which was established to accommodate seeds clearly referable to the Euphorbiaceae but for which extant generic affinities are not known ( Reid and Chandler 1933). Although the several London Clay species that Reid and Chandler placed in the genus do not preserve the arils, they typically possess a hilar truncation consisting of a pair of oblique ventral facets forming a broad angle of 100 to 130 degrees that likely indicates the position of the caruncle. Although the softer lipid-rich tissue of the caruncle might not be expected to preserve, it has been shown to preserve in casts of seeds within euphorbiaceous fruit from the early Oligocene of Peru ( Hamersma et al. 2022). Alternatively, the apical extension could suggest that this was a seed that was surrounded by a fleshy layer in life that was mostly not preserved except for the remaining apical fragment.
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