Palmocarpon wilcoxiana (Berry) Wang, Blanchard and Dilcher 2013

Na, Yuling, Blanchard, Jane & Wang, Hongshan, 2019, Fruits, seeds and flowers from the Puryear clay pit (middle Eocene Cockfield Formation), western Tennessee, USA, Palaeontologia Electronica (a 49) 23 (3), pp. 1-57 : 43-44

Palmocarpon wilcoxiana (Berry) Wang, Blanchard and Dilcher 2013

Figure 58

Description. See Wang et al. (2013, pp. 54–55, figures 47, 48) and Blanchard et al. (2016, p. 51, figure 55).

Number of specimens examined. 6. UF15820- 007246, 059470, 043616, 059402.

Remarks. The specimens from the Puryear clay pit show size variations from 1 to 2.8 cm long. For example, one endocarp (UF15820-043616; Figure 58.1 ) is 2.8 cm long and is larger than any specimens described from the Warman clay pit, Tennessee (1.5–2.5 cm long; Wang et al., 2013) and the Bovay clay pit, Mississippi (1.2–2.3 cm long; Blanchard et al., 2016). The specimens from the Puryear clay pit show a wider variation in size than those from the Warman or Bovay clay pits. The Puryear specimens include both the smallest and largest specimens of Palmocarpon wilcoxiana we have examined.

Lesquereux (1878; p. 119) established the fossil genus Palmocarpon for dispersed fruits from the Eocene strata in Colorado and New Mexico, with the following diagnosis: “Fruits of various size and forms, generally surrounded by a shelly pericarp, and found in connection with remains of palms.” These fruits co-occur with fragments of palm leaves in the same horizon. Therefore, Lesquereux (1878, pp.108-109) assigned this fossil genus to the Palmae, although he did not specify which characters he used to associate these fruits with the family.

Berry (1916; p. 331, pl. 99, figs. 5–7; p. 332, pl. 99, fig. 8.) first described four impression specimens from the Puryear clay pit, Tennessee, and assigned three to Nyssa wilcoxiana and one to Nyssa eolignitica . In his following publications, Berry assigned similar specimens to Nyssa wilcoxiana (Berry, 1924, 1930, 1941) and two other specimens to Palmocarpon syagrusioides (Berry, 1930) . These specimens may represent different preservation modes of the same fruit/seed type at various developmental stages. We propose that they all belong to the same fossil-genus Palmocarpon but available characters do not warrant their assignment to the genus Nyssa or the Palmae. We retain the species epithet wilcoxiana proposed by Berry (1916).

Figures

FIGURE 58. Palmocarpon wilcoxiana (Berry) Wang, Blanchard, and Dilcher, 2013: 1) UF15820-043616, a large endocarp ca. 29 mm long and 10 mm wide; 2) UF15820-059402, an endocarp with a middle ridge (indicated by the black arrow) and two grooves (indicated by the two white arrows); 3) UF15820-059470, a small endocarp; 4) UF15820-007246, an endocarp with a middle groove (indicated by arrow). All scale bars equal 3 mm.