Trigonobalanoidea americana Crepet and Nixon, 1989

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 : 15-20

cf. Trigonobalanoidea americana Crepet and Nixon, 1989

( Figure 14 )

Description. Immature pistillate infructescence, unbranched, with a slightly curved axis 3 cm long and 0.3 mm wide, bearing at least 32 alternately arranged immature fruits. Fruits sessile, 1.5 mm wide and up to 2 mm long, tapering toward the distal end. Two or three styles present.

Number of specimens examined. 1. UF15737- 059224.

Remarks. This specimen probably represents an immature infructescence of Trigonobalanoidea americana ( Crepet and Nixon, 1989) . However, the specimen is not well preserved. The demarcation of the cupule and fruit body is indistinct. One fruit available or a character is not observed.

with two styles and one fruit with three styles are observed.

Claiborne Fagaceae Fruit Type 3

( Figure 15.1-3 )

Description. Fruit 10 mm in diameter. Nutlets at least two, 2 mm long and 1 mm wide, enclosed by three spiny cupule valves; basal portion of the spines forming a web-like pattern with lamina tissues within the network and distal portion of the spines simple or branched. Simple trichomes present on the spines and lamina tissue. Peduncle short, 0.5–1 mm long with scattered simple spines. Number of specimens examined. 3. UF15815- 005347 ( Figure 15.1-2 ); UF15826-029215 (figure 2.F in DeVore et al., 2014); UF15826-51307 ( Figure 15.3 ; figure 17.4 in Wang et al., 2013; figure 2C in DeVore et al., 2014).

Remarks. All the fagaceous fruit types described in this manuscript are assigned to Fagaceae based on the presence of three spiny cupule valves characteristic of extant members of the family. Here we revise the Claiborne Fagaceae Fruit Type 3 to include three specimens, one from the Lamkin clay pit, Kentucky (UF15815-005347, Figure 15.1-2 ), and two specimens from the Warman clay pit, Tennessee. DeVore et al. (2014, figure 2F) illustrated detail of branched spines at the margin of the involucre of one specimen from Warman (UF15826- 029215). The second specimen from Warman (UF15826-51307) was illustrated by Wang et al. (2013, figure 17.4) and by DeVore et al. (2014, figure 2C) and is also presented here in Figure 15.3 . We transfer UF15826-029216 ( Figure 15.5 ), also illustrated by Wang et al. (2013, figure 17.1-3) to a new morphotype, Claiborne Fagaceae Fruit Type 5 (see discussion below), because of its large size. This revision increases the number of taxa/morphotypes recognized from Warman from 61 to 62.

The fruit size and the morphology of Claiborne Fagaceae Fruit Type 3 are similar to those of Catahoulea grahamii DeVore, Pigg, Dilcher and Freile ( DeVore et al., 2014; also see Figure 15.4 in this paper) from the Oligocene Huntsville locality, Texas. However, they differ in that each fruit of Claiborne Fagaceae Fruit Type 3 has a very short peduncle and three spiny cupule valves ( Table 3). The peduncle of the specimens from the Huntsville locality is very long relative to the involucre or the nutlet. For example, the peduncle of the holotype specimen ( DeVore et al., 2014, figure 1A; also see Figure 15.4 in this paper) is about four times as long as the nutlet and about two times as long as the involucre (spiny cupule valve or cupule). One other major difference is that the strongly cordate shape of the involucres (spiny cupule valves) of the Huntsville specimens is not as obvious on specimens from the Warman clay pit. Because of these differences and due to a limited number of specimens (one from the Lamkin locality, Kentucky and two from the Warman locality, Tennessee), we temporarily separate them as two different types. However, future collection may prove that these two fruit types belong to the same taxon. The fruits of Catahoulea grahamii may also have three spiny cupule valves. The spiny cupule valves of Claiborne Fagaceae Fruit Type 3, Claiborne Fagaceae Fruit Type 5, and C. grahamii , may not, or only slightly, enclose the nutlets.

Claiborne Fagaceae Fruit Type 4

( Figure 16 )

Description. Laterally preserved fruit 1.2 cm long and 6.5 mm wide. Apex acute. Dark core of nutlets at the basal end 5 mm at the widest point and 7 mm long, surrounded by a spiny cupule; spines of the cupule branched, intertwined, or interlocking. Three ridges/grooves present, converging at both ends of the fruit body. Peduncle 2 mm long and 0.5 mm wide, with spines.

Number of specimens examined. 1. UF15737- 059211.

Remarks. This specimen is similar to one of the two specimens described as Fagaceous Fruit Type 3 from the Warman clay pit, Tennessee ( Wang et al., 2013, p. 23, figure 17.4) in having spiny cupule valves. The spines of this fruit are branched and interlocking, usually obscuring the surface of the cupule. Based on this observation, this specimen is more closely related to Chrysolepis or Castanea than to Fagus ( Nixon, 1997) . In comparison with Claiborne Fagaceae Fruit Type 3 and Catahoulea grahamii, Claiborne Fagaceae Fruit Type 4 differs from them in having two large nutlets ( Table 3).

Claiborne Fagaceae Fruit Type 5

( Figure 15.5 )

Description. Fruit 2.5 cm in diameter. Nutlets not observed, three spiny cupule valves present; basal portions of the spines intertwined, forming a web-like pattern with laminal tissues within the network. Distal portions of the spines simple or branched. Simple trichomes present on the spines and lamina tissue. Peduncle stout, 10 mm long, and 1 mm wide with scattered simple spines.

Number of specimens examined. 1. UF15826- 29216 ( Figure 15.5 ).

Remarks. This specimen was included in Claiborne Fagaceous Fruit Type 3 by Wang et al. (2013, p. 26, figure 17.1-3). In this paper, we assign this specimen to a new type because of its large fruit size and its stout, relatively long peduncle ( Table 3). Table 3 summarizes the major characters of the five Claiborne Fagaceae fruit types and those of Catahoulea grahamii .

Figures

FIGURE 14. cf. Trigonobalanoidea americana Crepet and Nixon, 1989: 1) UF15737-059224. An immature infructescence with at least 32 sessile fruits. Scale bar equals 2 mm; 2) Enlargement of a fruit indicated by the upper arrow in Figure 14.1 to show two styles (s, indicated by arrow). Scale bar equals 0.5 mm; 3) Enlargement of a fruit indicated by the lower arrow in Figure 14.1 to show three styles (s, indicated by arrow). Scale bar equals 0.5 mm; 4) Counterpart of Figure 14.1 showing an immature infructescence. Scale bar equals 2 mm.

FIGURE 15. Claiborne Fagaceae Fruit Type 3 (1-3): 1) UF 15815-005347', Lamkin clay pit, Kentucky. Fruit showing two nutlets (n) and spiny cupule valve (c) with a web-like pattern. Scale bar equals 2 mm; 2) UF 15815-005347, Lamkin clay pit, Kentucky. Counterpart of Figure 15.1 showing a short peduncle (p). Note the overlap of spiny cupule valves (c). Scale bar equals 2 mm. 3) UF 15826-051307, Warman clay pit, Tennessee. Fruit showing spiny cupule valve (c) and short peduncle (p). Scale bar equals 2 mm. Catahoulea grahamii DeVore, Pigg, Dilcher and Freile, 2014: 4) UF 15841-062191, Huntsville, Texas. Fruit showing spiny cupule valve (c) and long peduncle (p). Scale bar equals 2 mm. Claiborne Fagaceae Fruit Type 5 (5) UF15826-29216, Warman clay pit, Tennessee. Specimen showing peduncle (p) and two overlapping spiny cupule valves (c). Scale bar equals 2 mm.

FIGURE 16. Claiborne Fagaceae Fruit Type 4: 1) UF15737-059211. Showing interwined spines, fruit body, a short peduncle (p). Scale bar equals 1 mm; 2) UF15737-059211'. Counterpart of Figure 16.1 showing three ridges converging at both ends of the fruit body and a short peduncle (p). Scale bar equals 1 mm.