Dipelta bovayensis, Blanchard, J, Wang, H & Dilcher, D, 2016

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 : 27-29

Dipelta bovayensis sp. nov.

( Figure 23 )

v. 2009 Dipelta sp. , Manchester et al., 2009, p. 18, fig. 14 .

Diagnosis. Fruit with two accrescent, membranous, wing-like bracts. Bract very wide ovate, margin entire, base auriculate, apex obtuse, with length/width ratio 1. Primary veins actinodromous, slightly converging toward the apex; medial primary vein extending directly toward the apex; lateral primary veins and branches from medial primary vein dichotomizing and joining adjacent branches to form reticulate meshes that become successively smaller toward the margin. Pedicel thin.

Description. Fruit with two accrescent, membranous, wing-like bracts, overlapping when compressed. Bract very wide ovate, margin entire, base auriculate, apex obtuse, 1.8 cm long and 1.8 cm wide (length/width ratio 1). Five primary veins present, actinodromous, slightly converging toward the apex; medial primary vein extending directly toward the apex; lateral primary veins and branches from medial primary vein dichotomizing and joining adjacent branches to form reticulate meshes that become successively smaller toward the margin. Pedicel thin, 10 mm long, and 0.5 mm wide.

Number of specimens examined. 1. Holotype (designated here): UF15737-049026 .

Occurrence. Bovay clay pit, Mississippi.

Age and horizon. Late early Eocene, Tallahatta Formation.

Remarks. The fruit (achene) and the persistent calyx are not observed. Manchester et al. (2009, p. 18, figure 14) assigned this specimen to extant Dipelta based on shared characteristic arrangement and venation of the bracts, and the presence of a narrow, persistent pedicel. Modern Dipelta are deciduous shrubs in mixed or broad-leaved forests (600–2400 m elevation) in Gansu, Guangxi, Guizhou, Hubei, Hunan, Shaanxi, Sichuan, and Yunnan Provinces of China ( Yang and Landrein, 2011). The enlarged bracts function in wind dispersal ( Manchester et al., 2009, figure 12). Fossils also have been reported from the early Oligocene of England ( Reid and Chandler, 1926; also see figure 13 in Manchester et al., 2009). This specimen from the lower Eocene Tallahatta Formation of Mississippi, USA, represents the earliest record of this genus.

Figures

FIGURE 23. Dipelta bovayensis sp. nov.: 1-2) UF15737-049026, 049026'. Part and counterpart of a specimen showing a fruit with two overlapping bracts (indicated by arrow), venation, and a slender pedicel. Note obtuse apex of the top bract. Scale bar equals 3 mm; 3) Enlargement of Figure 23.1 to show reticulate venation. Scale bar equals 3 mm.