Saportaspermum, Meyer and Manchester, 1997

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 : 42-51

Genus SAPORTASPERMUM Meyer and Manchester, 1997

Type species. Saportaspermum occidentalis Meyer and Manchester, 1997 , here designated.

cf. Saportaspermum sp.

( Figure 48 )

Description. Seed 2.2 cm long; wing 5 mm wide just above the seed and gradually narrowing toward the apex, with a few longitudinal striations. Seed body large relative to wing, 7 mm in diameter with radial striations.

Number of specimens examined. 1. UF15737- 059314.

Remarks. Saportaspermum is a fossil genus established by Meyer and Manchester (1997) (p. 161-162, pl. 74, figures 14-20) for winged seeds with uncertain affinities from the Oligocene Bridge

Creek flora. These seeds consist of an ovate to elliptical seed body that is oriented with the long axis at an oblique (40°) angle to the long axis of the veinless wing.

This single specimen from the Bovay locality possesses similar characters. However, the seed body possesses radial striations, and its shape is different from and its size is larger than other known Saportaspermum species ( Meyer and Manchester, 1997; Collinson et al., 2010, 2012; Kvaček and Wilde, 2010).

“ Acer ” knowltoni (Berry) Brown, 1940

( Figure 49 )

v. 1930 Phanerophlebites knowltoni Berry , page, 50, pl. 7, fig. 6.

v. 1940 “ Acer” knowltoni (Berry) Brown ; Brown, p. 351, figs. 7, 8.

Description. Samara 2.5 cm long and 1 cm at the widest part of wing. Wing rounded at apex, gradually narrowing toward the seed. Outer margin straight; inner margin straight at the proximal 67% and wavy at the distal 33%. Veins fine, numerous, diverging from the distal portion of the seed body. A protrusion ca 2 mm long with a fibrous tip present on one specimen.

Number of specimens examined. 2. UF15737- 059223 and an unnumbered specimen from Bolden locality, stored at the Field Museum of Natural History.

Remarks. Berry (1930, p. 48, plate 7, figure 6) first reported a fruit from the Holly Springs sand, Fayette County, Tennessee. He described it as a fragment of a pinna. Brown (1940, p. 351; figures 7, 8) transferred this specimen and two leaves, described by Berry (1930, p. 98, plate 21, figure 7; plate 42, figure 7) as Negundo knowltoni , to Acer knowltoni . The transfer of the fruit out of the fossil fern genus Phanerophlebites is valid. However, the transfer of the leaf specimens is invalid because these leaves and fruits are not attached. Also, assigning these fruits to the genus Acer is probably incorrect, because, as stated by Brown (1940), “the samaras have unusually long wings, and narrow heads which are seldom well enough preserved to show the attachment scar.” Even though the specimens are well preserved ( Figure 49.1-4 ), they do not appear to have the typical attachment scars that are often observed on fossil Acer fruits. In this report, we place these fruits in Angiosperm Incertae Sedis.

The venation pattern of the fruit is similar to that of extant fruits of Banisteriopsis ( Malpighiaceae ; Burnham, 1995), Securidaca ( Polygalaceae ; Burnham, 1995; Pigg et al., 2008) and Paleosecuridaca curtisii ( Polygalaceae ; Pigg et al., 2008), Tipuana (Legumnosae; Burnham, 1995), Loxopterygium ( Anacardiaceae ; Burnham and Carranco, 2004) and Deviacer ( Manchester, 1994; Chen and Manchester, 2015). However, the lack of detailed information of the seed and a stalk make it difficult to further compare this fruit with the modern and other fossil taxa.

Claiborne Fruit/Seed Type 6

( Figure 50 )

Description. Fruit/seed nearly spherical in outline, 0.9–1.2 cm in diameter. Surface with reticulate pattern, Fibers present on the fruit/seed surface.

Number of specimens examined. 2. UF15737- 059237, 059242.

Remarks. The outline of this fruit/seed type is similar to those Leguminosites chesterensis Berry specimens from Holly Springs sand, Tennessee, described by Berry (1930, p. 89, plate 14, figures 7-10). However, they differ in that specimens from the Bovay locality possess fiber strands.

Claiborne Fruit/Seed type 7

( Figure 51 )

Description. Disseminule spatulate, 5.5 mm long and ca 1.5 mm wide at the broadest end and tapering to 0.5 mm at the other. Margin entire. No surface pattern or ornamentation.

Number of specimens examined. 1. UF15837- 059319.

Remarks. This disseminule is similar to the fruits of Anisosciadium lanatum Boissier 1888 , of the Apicaceae. However, only one specimen is observed from this locality. There are not enough diagnostic characters to assess its modern affinities.

Claiborne Fruit/Seed Type 8

( Figure 52 )

Description. Compressed ovoid sclerotesta, surface smooth, 5.5 mm long and 3 mm wide; endotesta membranous.

Number of specimens examined. 1. UF15737- 059245.

Remarks. In gross morphology, this type is similar to the seeds of cf. Magnolia sp. ( Wang et al., 2013, p. 9, figure 5) and Corylopsis grotei ( Wang et al., 2013, p. 11, figure 8), both described from the Warman clay pit. However, characters at the chalazal end of the seed are not visible, and this makes it difficult to assign to either taxon.

Claiborne Fruit/Seed Type 9

( Figure 53 )

Description. Elliptical fruit/seed 9 mm long and 3.5 mm wide at widest point. Tapering at both ends. Longitudinal striations visible.

Number of specimens examined. 1. UF15737- 059324.

Remarks. The longtitudinal striations and the shape are similar to those of “ Aralia ” semina Berry (see Wang et al., 2013, p. 36-37, figure 30). But the size of “ Aralia ” semina seeds is only about 25% of Fruit/Seed Type 9. It is possible that this specimen may represent a beetle elytra. However, the presence of a thin layer of cuticle ( Figure 53.2 ; UF15737-059324’) makes it more likely to be a compressed fruit/seed.

Claiborne Fruit/Seed Type 10

( Figure 54 )

Description. Seed ca 2 mm in diameter. A thin layer of tissue up to 0.3 mm wide present on the periphery of the seed body.

Number of specimens examined. 1. UF15737- 059228.

Remarks. The thin layer of tissue around the seed body indicates that this specimen may represent a tiny winged seed.

Figures

FIGURE 48. cf. Saportaspermum sp. (1-2), UF15737- 059314, 059314'. Part and counterpart of specimen showing circular seed body and veinless wing. Note radial striations on the seed body. Scale bar equals 5 mm.

FIGURE 49. “Acer” knowltoni (Berry) Brown, 1940: 1-2) UF15737-059223, 059223'. Part and counterpart showing a samara. Note the protrusion with fibrous tip (indicated by arrow). Scale bar equals 2 mm; 3) A specimen from the Bolden clay pit, stored at the Paleobotany Collection at the Field Museum of Natural History, showing a samara and its venation. Scale bar equals 3 mm; 4) Enlargement of Figure 49.3 to show the smooth curvature of the inner margin of the base of the samara (indicated by arrow) and the seed outline. Scale bar equals 1 mm.

FIGURE 50. Claiborne Fruit/Seed Type 6: 1-2) UF15737-059237, 059237'. Part and counterpart of a specimen showing a spherical fruit/seed. Note fibers on the surface (indicated by arrows). Scale bar equals 1 mm; 3) UF15737-059242. Showing a spherical fruit/seed. Scale bar equals 1 mm; 4) Enlargement of Figure 50.3 (indicated by arrow) to show fibers associated with the fruit/seed. Scale bar equals 0.5 mm; 5) Enlargement of Figure 50.2 (indicated by arrow) to show fibers associated with the fruit/seed. Scale bar equals 0.5 mm.

FIGURE 51. Claiborne Fruit/Seed Type 7 (1-2), UF15837-059319. Showing two possible orientations of a disseminule. It may represent a fruit with a persistent style (indicated by arrow) as in Figure 51.1 or a fruit with a pedicel (indicated by arrow) in Figure 51.2. Scale bar equals 0.5 mm.

FIGURE 52. Claiborne Fruit/Seed Type 8 (1-2), UF15737-059245, 059245’. Part and counterpart of a specimen showing compressed ovoid sclerotesta with smooth surface and membranous endotesta (indicated by arrow in Figure 52.2). Scale bar equals 1 mm.

FIGURE 53. Claiborne Fruit/Seed Type 9 (1-2), UF15737-059324, 059324'. Part and counterpart of a specimen showing elliptical fruit/seed with longitudinal striations. Scale bar equals 1 mm.

FIGURE 54. Claiborne Fruit/Seed Type 10 (1-2), UF15737-059228, 059228’. Part and counterpart of a specimen showing thin layer of tissue (indicated by white arrow) and hilum scar (at the bottom of seed as indicated by black arrows). Scale bar equals 0.5 mm.