Palmocarpon wilcoxiana (Berry) Wang, Blanchard, and Dilcher, 2013

Blanchard, J, Wang, H & Dilcher, D, 2016, Fruits, seeds and flowers from the Bovay and Bolden clay pits (early Eocene Tallahatta Formation, Claiborne Group), northern Mississippi, USA, Palaeontologia Electronica 19 (3), pp. 1-59 : 51-53

Palmocarpon wilcoxiana (Berry) Wang, Blanchard, and Dilcher, 2013

( Figure 55 )

Description. Endocarp elliptic, 1.2–2.3 cm long and 0.7–1 cm wide. Distal fine projections 1–2 mm long.

Number of specimens examined. 3. UF15737- 008221, 059231, 059243a.

Remarks. This type of endocarp is common in the Claiborne Group (see Wang et al., 2013, p. 54-55, figures 47, 48).

Undetermined

Claiborne Undetermined Structure 1

( Figure 56 )

Description. Structure 8 mm long and 7 mm wide with a curved, median groove/ridge. Broadest at the base. No ornamentation observed.

Number of specimens examined. 1. UF15737- 059229.

Remarks. This structure may represent one valve of a capsule, a bud scale, or a sepal of a flower. However, none of the known fruit capsules or flowers from the Claiborne Group seems to possess valves or sepals with similar morphology.

The median groove/ridge is similar to that of Carpolithus sophorites from the Warman clay pit ( Wang et al., 2013, p. 51, figure 44). This specimen from Bovay differs from C. sophorites in having a rough surface, probably representing an internal mold of a seed. It is similar to Carpolithus puryearensis ( Berry 1916b, p. 351, plate 104, figure 8) in that both have central grooves/ridges. They differ in that C. puryearensis is larger (15 mm long and 8 mm wide), and its central groove/ridge is thin relative to the width of the entire structure.

Claiborne Undetermined Structure 2

( Figure 57 )

Description. Structure rectangular in outline, 12 mm long and 9 mm wide with a lengthwise central groove dividing it into symmetrical portions.

Number of specimens examined. 1. UF15737- 059297.

Remarks. This structure differs from Undetermined Structure 1 and Carpolithus sophorites from the Warman clay pit ( Wang et al., 2013, p. 51, figure 44) in that it is larger and the groove is straight.

Claiborne Undetermined Structure 3

( Figure 58 )

Description. Structure with about 24 linear, basally fused units encircling a central area approximately 1 mm in diameter; each unit ca 2 mm long and 0.3 mm wide, with an acute, curved apex.

Number of specimens examined. 1. UF15737- 059244.

Remarks. This structure may represent a basally fused calyx or a stem sheath on the node of Equisetum .

Claiborne Undetermined Structure 4

( Figure 59 )

Description. Fragment of structure 2 mm long and 1 mm wide, with scale-like, irregular hexagonal surface pattern.

Number of specimens examined. 1. UF15737- 008228.

Remarks. The hexagonal surface pattern of the specimen is similar to that of the seed wing of some members of the Rubiaceae , e.g., Pinckneya bracteata (W. Bartram) Rafinesque, 1827 . Fossils of the Rubiaceae have been reported from as early as the middle Eocene of Oregon and Washington, USA and Hainan, China, and the late Eocene of Panama and Australia ( Graham, 2009; Shi et al., 2012). Leaves assigned to the Rubiaceae have also been reported from the Claiborne Group from Tennessee ( Roth and Dilcher, 1979).

Figures

FIGURE 55. Palmocarpon wilcoxiana (Berry) Wang et al., 2013: 1-2) UF15737-008221, 008221'. Part and counterpart of a specimen showing elliptic endocarp and fiber strands (indicated by arrow). Scale bar equals 2 mm; 3) UF15737-059231. Specimen showing elliptic endocarp. Note fine fiber strands at the distal end (indicated by arrow). Scale bar equals 2 mm; 4) UF15737-059243a. Specimen showing fiber strands/projections at the distal end (indicated by arrow). Scale bar equals 2 mm.

FIGURE 56. Claiborne Undetermined Structure 1 (1-2), UF15737-059229, 059229'. Specimen showing a median ridge on part and a median groove on the counterpart. Scale bar equals 1 mm.

FIGURE 57. Claiborne Undetermined Structure 2, UF15737-059297. Specimen showing a symmetric structure with a central groove. Scale bar equals 2 mm.

FIGURE 58. Claiborne Undetermined Structure 3, UF15737-059244. Specimen showing linear, basally fused units encircling a central area. Note that the apices of the linear units (indicated by arrows) are curved into the matrix. Scale bar equals 1 mm.

FIGURE 59. Claiborne Undetermined Structure 4, UF15737-008228. Specimen showing scale-like, irregular hexagonal surface pattern of the structure. Scale bar equals 0.25 mm.