Carpolithes BRONGN.

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 : 67

Genus Carpolithes BRONGN.

Carpolithes sp. 1

Text-fig. 8a–e

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

PAL 772366.

D e s c r i p t i o n. Ovoid to obovoid in lateral view, inflated, three sided in cross section ( Text-fig. 8a–c ). 13.4 mm long, 8.2 by 8.4 mm in cross section. Two of the three angles defined by strong longitudinal ridges, the third angle eroded, without a pronounced ridge ( Text-fig. 8d ). The most pronounced ridge bounded by two faint lineations that meet near the more rounded end. The faces between the ridges (where not eroded) with fainter longitudinal striations. The rounded end with a small, circular raised point, possibly of attachment. The opposite end more pointed, but with the tip eroded. The structure is almost split in half at the more pointed end.

D i s c u s s i o n. The presence of a scar on the rounded end leads us to postulate that this is the base, although that might be in error. The size and three angled aspect of the fossil, coupled with the faint lineations adjacent to the most well-developed ridge, led to the initial hypotheses that this might be a three-angled endocarp with three valves, perhaps like Nyssa . However, these potential valves are more elongate than those of Nyssa , which has valves limited to the apical half of the endocarp. If it were Nyssa , this would also suggest that the scar on the rounded end was in fact associated with the stigma, and that the pointed and eroded end was the base. However, in the absence of further detail, we choose to treat this as Carpolithes .

Figures

Text-fig. 8. Carpolithes (a–t). a–e: Carpolithes sp. 1. USNM PAL 772366. Scale bar = 1cm. a: Lateral view of endocarp, note two longitudinal ridges. b: Lateral view of endocarp rotated 90° from (a), note singlelateral ridge in center, a, b reflected light, palladium coated. c: Lateral view, Micro-CT scan surface rendering. d: View of rounded end of the endocarp, reflected light, palladium coated. e: View of the opposite (pointed) end of the endocarp, note split; reflected light, palladium coated. f–j: Carpolithes sp. 2. USNM PAL 772367. Scale bar = 5mm. f: Lateral view, base down; note raphe-like structure (arrow), reflected light, palladium coated. g: Lateral view, the raphe-like structure extending vertically from the base. h: Lateral view, rotated 90° from (g). i: Lateral view, the opposite face to that in (h). j: Basal view, raphe-like structure running from the center to the right of the image. g–j: CT scan surface renderings. k–o: Carpolithes sp. 3 USNM PAL 772368. Scale bar = 5mm. k: Ventral view of the specimen, note flared apical extension, reflected light, uncoated. l: Dorsal view illustrating the flared apical extension, rotated 180o from (k). m: Lateral view rotated 90° from that in (l). n: Apical view, the apical extension with central pore (arrow) and a clear lineation running down the side to the top of the image. o: Basal view. l–o: Micro-CT scan surface renderings. p–t: Carpolithes sp. 4. USNM PAL 772369. Scale bar = 3mm. p: Basal view illustrating the concentric rings of radiating possible cells surrounding a central depression. q: Lateral view, base down, note possible cellular pattern. r: Lateral view, rotated 180° from (q), base down; p–r: reflected light, palladium coated. s, t: Basal and lateral views, micro-CT scan surface renderings.