Carpolithes sp. 5

Tiffney, Bruce H. & Manchester, Steven R., 2022, The Early Middle Eocene Wagon Bed Carpoflora Of Central Wyoming, U. S. A., Fossil Imprint 78 (1), pp. 51-79 : 70

Carpolithes sp. 5

Text-fig. 9a–d

M a t e r i a l. One specimen, chalcedony cast, USNM

PAL 772370.

D e s c r i p t i o n. Seed broadly elliptic in face view, 7.8 mm long, slightly dorsiventrally flattened, 5.8 mm by 4.9 mm, oval in cross-section. Seed with a circular, raised point of attachment with a central depression. Lateral to this on one side is a raised ridge that parallels one margin of the wider axis, disappearing into the seed margin about halfway along its length ( Text-fig. 9a, d ). Surface peeling off in a manner suggestive of cell layers ( Text-fig. 9c ), but more likely erosional. No internal structure apparent.

D i s c u s s i o n. Carpolithes species 5 is interpreted as an anatropous seed with an adjacent apical hilum and micropyle, and a subtending lateral raphe, melding into the seed about halfway down the margin. In these characters, they bear a resemblance to the seeds of Nymphaeaceae L. However , the separation of the hilum and micropyle is not distinct as in many Nymphaeaceae , and no details of the cellular structure of the seed coat are apparent, both critical in making a more certain assignment.

Figures

Text-fig. 9. Carpolithes (a–r). a–d: Carpolithes sp. 5. USNM PAL 772370. Scale bar = 5mm, reflected light, palladium coated. a: Lateral view of seed, apex up, possible raphe descending from apex toward viewer. b: Lateral view of seed, apex up, possible raphe on right. c: Lateral view, opposite side, apex up, possible raphe on left. d: Apical view, note central pit with raphe descending towards bottom margin. e–h: Carpolithes sp. 6. USNM PAL 772371. Scale bar = 5mm. e: Basal view illustrating depression and keel in plane of bisymmetry, reflectedlight, palladium coated. f–h: Micro-CTscansurface rendering.f: Lateralviewshowingrelatively smoothrounded surface. g: Specimen rotated 180° from (f), surface partially eroded. h: Longitudinal view, showing median keel. i–m: Carpolithes sp. 7 USNM PAL 772372. Scale bar = 5mm. i: View of intact face of globose fruit, possible apical constriction at top. j: Lateral view, intact surface to right, possible apical constriction at top, both micro-CT scan surface renderings. k: Apical view. l: Face view illustrating the mineral filling and the fine, radiating structure of the fruit wall on the left and right margins, both reflected light, palladium coated. m: Closeup of the cellular layer on the left of (l), micro-CT scan surface rendering. n–p: Carpolithes sp. 8. USNM PAL 772373. Scale bar = 3mm, reflected light, palladium coated. n: Lateral view of pyrene-like structure, one ridge running vertically in the center of view, the other two forming the left and right margins. o: Lateral view of pyrene-like structure, ridge in (n) on the left. p: End-on view illustrating one convex, one concave, and one relatively flat to very slightly concave face. q, r: Carpolithes sp. 9 USNM PAL 772374. Scale bar = 5mm, reflected light, palladium coated. q: Exterior of the smooth broken half-sphere. r: Interior of the broken half-sphere.