Paleopanax boldensis, 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 : 29-42

publication ID

https://doi.org/ 10.26879/579

persistent identifier

https://treatment.plazi.org/id/A21187CB-FF9C-FFB4-46CA-FC322D81FBE8

treatment provided by

Felipe

scientific name

Paleopanax boldensis
status

sp. nov.

Paleopanax boldensis sp. nov.

( Figure 24 View FIGURE 24 )

Diagnosis. Fruit capsule small, globose, dehiscent, with three persistent styles, an epigynous disc, and a long pedicel; carpel D-shaped.

Description. Infructescence with one middle acrocidal capsule flanked by two lateral capsules. Middle fruit small, globose, dehiscent, ca 4 mm in diameter; pedicel 2 mm long and 1 mm wide. Two lateral fruits also globose, 3.5 and 4 mm in diameter respectively; three styles, each ca 0.8 mm long and 0.2 mm wide; pedicels 5 mm long and 1 mm wide. Peduncle 16 mm long and 1 mm wide.

Number of specimens examined. 1. UF15738- 059493 (holotype, designated here) .

Occurrence. Bolden clay pit, Mississippi.

Age and Horizon. Early Eocene, Tallahatta Formation, Claiborne Group.

Etymology. The species name refers to its occurrence at the Bolden locality, Mississippi.

Remarks. The diagnostic characters of the new species are consistent with those of the fruits from the middle Eocene Nut Beds Flora, Clarno Formation, Oregon ( Manchester, 1994, p. 38-39, pl. 7, figures 3-4). Petrified wood with possible affinity to Araliaceae was also reported by Wheeler and Manchester (2014) from the Clarno Formation. It differs from the specimens from the Nut Beds in not having an obvious epigynous disc. Leaves belonging to the family Araliaceae , i.e., Dendropaber of locules in each fruit is unknown. Based on the impression of UF15738-059493’ ( Figure 24.3- 4 View FIGURE 24 ), at least three are present. The number of seeds in each locule is also unknown. Based on the impressions of UF15738-059493’ ( Figure 24.3-4 View FIGURE 24 ) and UF15738-059493 ( Figure 24.1 View FIGURE 24 ), it seems each locule bears only one seed.

The D-shaped carpel and the fruit size of the Bolden specimen is similar to the specimens that Berry (1930) described as Rubiacites wilcoxensis (Bell City pit, Calloway County, Kentucky; p. 133, plate 45, figure 8) and Rubiacites sphericus (Bell City pit, Kentucky; p. 133, plate 45, figure 10). The Rubiacites wilcoxensis specimen does seem to have an epigynous disc but it does not appear to be dehiscent. The other two specimens Berry (1930) described as Rubiacites sphericus (Bradley pit and Puryear pit, Tennessee; p. 133, plate 45, figures 9, 11) are larger. All specimens described by Berry do not have persistent styles.

The size of the capsules from the Bolden locality is similar to that of the fruits of Decodon gibbosus (E. Reid) E. Reid in Nitikin ( Lythraceae ) reported from the early Miocene of northern Bohemia ( Kvaček and Sakala, 1999, p. 205, figure 3). They differ in that the pedicellate capsules of D. gibbosus are axillary and that each capsule contains at least 10 seeds.

nax eocenensis Dilcher and Dolph, 1970, have been reported from other Claiborne localities ( Dilcher and Dolph, 1970). Araliaceous woody racemes of globose infructescences were also reported from the late Eocene or early Oligocene Florissant flora, Colorado ( Manchester, 2001).

The middle capsule seems to be the oldest among the three fruits because the styles had already fallen off before preservation. The two lateral fruits still have their styles attached. The num-

Angiosperm Incertae Sedis – Flowers

cf. “ Solanites ” saportanus (Berry) Martínez-Millán, 2010

( Figure 25 View FIGURE 25 )

v. 1916 b Solanites saportana Berry , p. 348, pl. 106, figs. 4-5.

v. 2010 Solanites saportanus (Berry) ; Martínez-Millán, p. 166-167, fig. 3.3 A-C.

v. 2014 Solanites saportanus (Berry) ; Millan and Crepet, p. 79-80, fig. 3 a-b.

Description. Flower 6-merous, 9 mm in diameter, with a shallow floral cup ca 4 mm in diameter. Perianth parts (sepals?) triangular, 3 mm long and 2 mm wide at the base; a midvein present in each part. Pedicel present, ca 0.5 mm in diameter.

Number of specimens examined. 1. UF15737- 008222.

Remarks. Solanites is a fossil genus established by Saporta (1862; see Martínez-Millán, 2010 and Millan and Crepet, 2014 for nomenclatural history) for actinomorphic, 5-merous, gamopetalous flowers with five stamens (short filaments and elongated anthers) alternating with the petals. The type species is Solanites brongniartii . Saporta (1862) assigned several members of the genus to the

BLANCHARD, WANG, & DILCHER: FOSSIL PLANTS FROM MISSISSIPPI

Solanaceae . However, phylogenetic analysis ( Martínez-Millán, 2010; Millan and Crepet, 2014) suggests that the genus is best placed as Incertae Sedis within the Euasterids.

Berry (1916b) described one specimen from the Holly Springs locality, Tennessee, as Solanites saportana . Martínez-Millán (2010) and Millan and Crepet (2014) corrected the species epithet and changed the species name to S. saportanus and noted that the only feature it shares with the type species, S. brongniartii , is pentamery. They further suggested that this and three other species from North American be removed from the genus because they show little resemblance to the type species.

The presence of a pedicel on the Bovay specimen is indicated by the depression at the center of the floral cup. It is similar to the two flowers described by Berry (1916b) in having a shallow floral cup and a midvein in each floral part. However, it differs from Berry’s specimens in having six floral parts.

Solanites ” sarachaformis Berry, 1930

( Figure 26 View FIGURE 26 )

v. 1930 Solanites sarrachaformis Berry , p. 131; pl. 25, fig. 31.

Description. A vertically preserved flower about 10 mm in diameter. Four perianth parts (sepals?) present, each part ovate, ca 4.5 mm long, and 3.5 mm wide; 5 veins present on each part. A shallow floral cup present, formed by fusion of the basal 20% of floral parts.

Number of specimens examined. 1. UF15737- 049569.

Remarks. Based upon Article 60 (Section 1, Chapter IX) of the International Code of Nomenclature for Algae, Fungi, and Plants ( McNeill et al., 2012), Martínez-Millán (2010) noted the typographical error of Berry (1930) and corrected the species epithet from sarrachaformis to sarachaformis. This specimen is similar to the one described by Berry (1930) from the Holly Springs, Mississippi locality ( Berry, 1930; p. 131, plate 25, figure 31) except that it has four floral parts. The species differs from the other two species, i.e., cf. “ Solanites ” saportanus (Berry) Martínez-Millán and “ Solanites ” pusillus Berry , in having an inconspicuous floral cup ( Table 4).

Claiborne Floral Type 5

( Figure 27 View FIGURE 27 )

Description. Vertically preserved flower 2.2 cm in diameter showing five separate ovate, finely veined perianth parts; the most complete being 7 mm long and 5 mm wide at the widest point with a rounded apex. Ovary 5 mm in diameter.

Number of specimens examined. 1. UF15738- 008216.

Remarks. Fifteen specimens have been discovered from the Warman clay pit, Tennessee ( Wang et al., 2013). The venation of the floral parts on this specimen from Bolden clay pit, Mississippi, is not as well preserved as that of the Warman specimens. Many depressions on one part of the central column may represent the attachment scars of the stamens. We assign this specimen to Claiborne Floral Type 5 based on the size of the flower and the shape and number of perianth parts ( Table 4).

Claiborne Floral Type 7

( Figure 28 View FIGURE 28 )

Description. Flower ca. 11 mm in diameter, vertically preserved showing three petals alternating with three sepals. Ovary inferior, 3 mm in diameter; sepals triangular, 3 mm long and 2 mm wide, apex acute; petals 4 mm long and 1 mm wide.

Number of specimens examined. 1. UF15737- 059208a.

Remarks. The sepals and petals seem to be attached to the rim of the depression, indicating an inferior ovary. The petals slightly overlap the adjacent sepals. The presence of an ovary is indicated by the hole at the center of the depression.

Claiborne Floral Type 8

( Figure 29 View FIGURE 29 )

Description. Flower 8 mm in diameter, consisting of at least seven perianth parts, an ovary within a hypanthium with a thickened rim, stamens, and a pedicel. Perianth parts triangular, 1.5–2.5 mm long and 1.5–2 mm wide, trichomes present; each with at least five relatively strong veins. Ovary 2 mm in diameter, trichomes present; hypanthium rim ca. 0.5 mm thick. Four or five stamens observed, attached to hypanthium rim; filaments ca 2.5 mm long and 0.1 mm wide. Pedicel 0.5 mm in diameter. Number of specimens examined. 2. UF15737- 049567a, 049570.

Remarks. It is difficult to separate these perianth parts into sepals and petals. Although only seven floral parts are observed on one specimen, their arrangement on the rim indicates probable presence of an eighth perianth part ( Figure 29.1-2 View FIGURE 29 ; Table 4). The presence of a pedicel is indicated by the depression at the center of the compressed flower ( Figure 29.1 View FIGURE 29 ). It seems that at least four or five stamens are attached at the base of each sepal/petal ( Figure 29.3-4 View FIGURE 29 ).

Claiborne Floral Type 9

( Figure 30 View FIGURE 30 )

Description. Vertically preserved flower 6 mm in diameter with five perianth parts; perianth parts separate, 2 mm long, and 1 mm wide, triangular, acute at apices. Ovary 2–3 mm in diameter, with a prominent rim at least 0.5–1 mm thick. A pedicel present, ca. 0.2 mm wide.

Number of specimens examined. 2. UF15737- 059240; 059247.

Remarks. The presence of a pedicel is indicated by a central depression on one part of the specimen ( Figure 30.1 View FIGURE 30 ) and a central small circle on the counterpart specimen. The thickness of the ovary rim is defined by the two concentric outer circles ( Figure 30.3 View FIGURE 30 ). The prominent ovary (hypanthium) rim of this specimen is similar to Solanites pusillus Berry (also see Wang, et al., 2013, p. 41, figure 35; Table 4). However, they differ in that the perianth parts do not have a midvein. The ovary rim is also similar to that of a flower from Webb County, Texas, described as “ Diospyros ” mirafloriana by Berry (1924, p. 195, plate 40, figure 5) and Ball (1931, p. 170, plate 32, figure 5). They differ in that the flower reported by Berry is almost five times larger. This flower differs from Eoglandulosa warmanensis (Taylor and Crepet, 1987, figures 1- 6, 9-13, 33, 34; Wang et al., 2013, figure 21) in that the flower from Bovay is smaller, the floral parts are separate, and the trichomes are absent from all floral parts.

Claiborne Floral Type 10

( Figure 31 View FIGURE 31 )

Description. Flower 6-merous, vertically preserved, ca 15 mm in diameter; perianth parts (petals?), ovate, about 5 mm long, and 2–2.5 mm wide; faint veins present. Inferior (?) ovary about 5 mm in diameter.

Number of specimens examined. 1. UF15737- 059243b.

Remarks. The perianth parts do not seem to overlap, and they seem to be attached to the upper rim of the compressed ovary, indicating an inferior ovary. This flower is similar to “ Solanites ” saportanus (Berry) Martínez-Millán in that both flower types are 6-merous. They are different in that the floral parts of “ Solanites ” saportanus (Berry) Martínez-Millán are triangular and possess a prominent midvein ( Table 4). The shape of the perianth parts of this 6-merous flower is similar to those of Wuyunanthus hexapetalus Wang, Li, Li, and Fu, 2001 , a flower described from the Paleocene Wuyun Formation from northeast China. They differ in that the flower from Bovay, Mississippi, is smaller and it does not have a hexagonal disk.

Claiborne Floral Type 11

( Figure 32 View FIGURE 32 )

Description. Vertically preserved flower ca 11 mm in diameter with four perianth parts and a long pedicel. Perianth parts ovate in outline, separate, 5 mm long, and 3 mm at middle. Pedicel 10 mm long and 0.5 mm wide. Ovary ca 2 mm in diameter.

Number of specimens examined. 1. UF15737- 008227.

Remarks. The pedicel seems to be very thin. It is possible that it represents a long exserted style of a flower. It is also possible that this flower may be 3-merous. But based upon its asymmetry and the large gap between two adjacent floral parts ( Figure 32.1 View FIGURE 32 ), we conclude that this flower possesses four floral parts. Table 4 summarizes the descriptions of Claiborne Floral Types 5, 8–11 and also “ Diospyros ” mirafloriana, Eoglandulosa warmanensis , “ Solanites” pusillus , “ Solanites” saportanus , and “ Solanites ” sarachaformis. These taxa/morphotypes are similar in their vertical preservation and radial symmetry. It is likely that most have a hypanthium.

Claiborne Floral Type 12

( Figure 33 View FIGURE 33 )

Description. A cluster of vertically and laterally compressed flowers subtended by two large (ca 1.8 cm long and 5 mm wide) bracts/leaves and one small, incomplete bract/leaf; the two large bracts/ leaves emerging 180° apart. One laterally compressed flower ca 7 mm long (including pedicel) and 7 mm wide; ovary inferior, obconic, ca 2 mm long, and 2 mm wide; pedicel short, ca 1.5 mm long and 0.5 mm wide. Perianth not well preserved. No other floral parts present. A second laterally compressed floral structure appears to be in a later developmental stage, showing a possible developing fruit ca 3 mm in diameter. Anthers observed only in vertically compressed flowers; anthers ca 2 mm long and 1 mm wide; filaments not observed. A prominent midvein present on the two large bracts/ leaves.

Number of specimens examined. 1. UF15738- 008217.

Remarks. This cluster of flowers is unique in that it is subtended by at least three bracts or leaves. The cluster could be a mixture of staminate and pistillate flowers.

Claiborne Floral Type 13

( Figure 34 View FIGURE 34 )

Description. Small, laterally preserved flowers about 3.5 mm long, 2 mm wide at the apex of the closed or fused perianth, and 1 mm wide at the base. Style 0.5 mm long; filaments 2 mm long. Pedicel short, 0.5 mm long.

Number of specimens examined. 1. UF15737- 059232.

Remarks. A total of six small, dispersed, laterally preserved flowers are observed. One flower shows exserted filaments about 2 mm in length.

Claiborne Floral Type 14

( Figure 35 View FIGURE 35 )

Description. Laterally preserved flower, sympetalous, small, 7 mm long, and 6.5 mm wide at the distal portion. Perianth tube cupuliform, thin, with three lobes; simple trichomes present on entire perianth. Remnant of calyx observed at the base of the perianth tube.

Number of specimens examined. 1. UF15738- 052528.

Remarks. This cupuliform perianth is unique among the flowers observed from the Claiborne Group. The presence of a calyx (or sepals) is inferred from the thick carbonaceous material at the base of the perianth tube. Flowers with cupuliform perianth tubes occur in many angiosperm families, such as some members of the Ericaceae and Lauraceae ( Li et al., 2008) .

Claiborne Floral Type 15

( Figure 36 View FIGURE 36 )

Description. Laterally preserved flower showing three separate (but not spreading) perianth parts about 2 mm long and 0.8–1.2 mm wide. Apex of each perianth part acute. Receptacle 1.5 mm wide and ca 1 mm high tapering to pedicel 1 mm long and 0.8 mm wide.

Number of specimens examined. 1. UF15737- 059251.

Remarks. This flower differs from Lauroflorum warmanensis ( Wang et al., 2013, p. 4, figure 3) in having a very short pedicel and a much smaller size. The gross shape of the lateral view is similar

(1916b) specimen is larger and has a much longer pedicel.

Claiborne Floral Type 16

( Figure 37 View FIGURE 37 )

Description. Small laterally preserved floret 1.5 mm in diameter. Calyx fused at base with a shallowly lobed upper margin. Up to three perianth parts extend about 0.5 mm beyond the calyx. Ovary 1 mm in diameter. Style 0.5 mm long with an expanded stigmatic disc ca 0.3 mm wide. Pedicel very thin, ca 1–2.5 mm long and 0.2 mm wide.

Number of specimens examined. 2. UF15737- 059226, 059317.

Remarks. On one specimen (UF15737-059226), there are at least 18 scattered florets preserved together with an unknown floral structure.

Claiborne Floral Type 17

( Figure 38 View FIGURE 38 )

Description. Laterally preserved flower ca 10 mm long and 2.5 mm wide at widest point of the ovary; ovary obtriangular, 2 mm long and 2.5 mm wide; perianth parts elliptic, 4 mm long and 2 mm wide, with a prominent midrib. Filaments numerous, ca 4–5 mm long. Pedicel ca 3.5 mm long and 1 mm wide.

Number of specimens examined. 1. UF15738- 060634, 060634’.

Remarks. Table 2 shows the differences among Claiborne Fabaceae Floral Types 1 and 2, Protomimosoidea buchananensis , and Claiborne Floral Types 17 and 18.

to Claiborne Floral Type 1 and Claiborne Floral Type 2 ( Wang et al., 2013, figure 36), but it is much smaller in size compared with the Warman flowers. The size and number of floral parts (three) of Laurophyllum florum Berry (1916b , plate 86, figure 6) seem to be similar to the Bovay flower, but Berry’s

Claiborne Floral Type 18

( Figure 39 View FIGURE 39 )

Description. Laterally preserved flower(s?) with ovary, stamens with partially fused filaments, and a short pedicel. Ovary spherical, 2 mm in diameter with several (four?) fragments of perianth attached, one extending 0.5 mm beyond the apex of the ovary. Filament column ca 2 mm long and 0.5 mm wide, with 4–6 anthers. Anthers 0.5–1 mm long and 0.5 mm wide, with strong connectives. Pedicel 1 mm long and 0.5 mm wide.

Number of specimens examined. 2. UF15737- 059323, 059241a.

Remarks. One specimen ( Figure 39.2 View FIGURE 39 ) shows a filament splitting from the central column. This indicates that distal portions of the filaments are separate (see Table 2).

Claiborne Floral Type 19

( Figure 40 View FIGURE 40 )

Description. Floral part 5.5 mm long and 0.7 mm wide. Apex attenuate; a midrib and thin lateral veins present.

Number of specimens examined. 1. UF15737- 059316.

Remarks. This specimen may represent a petal, a stipule, or a wing of a fruit/seed.

Claiborne Floral Type 20

( Figure 41 View FIGURE 41 )

Description. A mass of stamens laterally preserved. The size of the filament zone about 7 mm long and 3 mm wide and the size of the anther zone about 10 mm long and 1.5 mm wide; anthers suborbiculate, ca 0.8 mm long and 0.6 mm wide.

Number of specimens examined. 2. UF15737- 059209.

Remarks. This stamen mass is different from all other Claiborne reproductive material recognized.

Angiosperm Incertae Sedis – Infructescences

Sparganium ” sp.

( Figure 42 View FIGURE 42 )

v. 1930 Sparganium ? sp., Berry, p. 54; pl. 8, fig. 1.

v. 2013 “ Sparganium ” sp. Wang, Blanchard, Dilcher, fig. 49.

Description. Globose infructescence ca 8.0 mm in diameter, bearing numerous fruits ca 0.5 mm in diameter. Stalk ca 6 mm long and 1 to 1.5 mm wide, covered with trichomes. Triangular projections ca 0.25 mm long present on each fruit.

Number of specimens examined. 1. UF15737- 027592.

Remarks. This specimen from the Bovay clay pit is the same as the two specimens from the Warman clay pit ( Wang et al., 2013), except that it is larger.

Claiborne Infructescence Type 4

( Figure 43 View FIGURE 43 )

Description. Incomplete catkin ca 7 cm long and 5 mm wide; axis ca 1 mm wide. Florets/fruits sessile, ca 1.5 mm long and 0.7 mm wide, attached in the axils of bracts; three or four florets/fruits per centimeter. Subtending bract simple, ca 2.5 mm long, extending from the axis at a 45° angle.

Number of specimens examined. 1. UF15737- 059313.

Remarks. The specimen is poorly preserved. However, this catkin can be distinguished from Eokachyra aeolius Crepet, Dilcher, and Potter, 1975 (see Wang et al., p. 24, figure 18) in that the bracts of E. aeolius are three to four lobed, and the florets are densely arranged on the axis. It differs from the catkin of Eomimosoidea plumosa Crepet and Dilcher, 1977 in that the bract subtending each flower of E. plumosa is auricular in shape (see Wang et al., 2013, p. 13, figure 10, 11). It differs from Trigonobalanoidea americana Crepet and Nixon, 1989 in that there are no bracts subtending the florets/fruits of T. americana (see Crepet and Nixon, 1989, p. 851; figure 28).

Claiborne Infructescence Type 5

( Figure 44 View FIGURE 44 )

Description. Infructescence pedunculate, about 5 mm in diameter, bearing at least seven crescentshaped, winged fruits ca 2 mm long and 1 mm Number of specimens examined. 1. UF15737- 059315.

Remarks. The number of fruits in each infructescence and the number of perianth parts associated with each fruit are unknown. The depression on each fruit probably indicates the presence of a pedicel. This infructescence type is different from Infructescence Type 1 from the Warman clay pit, Tennessee ( Wang et al., 2013, figure 31) in having a spherical shape, smaller individual fruits, presence of persistent perianth parts, and the absence of spines on the peduncle.

wide. Receptacle 4 mm wide and 2 mm wide; peduncle 4 mm long and 0.5 mm wide.

Number of specimens examined. 2. UF15737- 059234, 059250.

Remarks. This small infructescence differs from all other infructescences described from the Claiborne Group in its small, winged fruits attached to a receptacle. The specimen illustrated in Figure 44.2 View FIGURE 44 (UF15737-059234) may be an infructescence at a less mature stage.

Claiborne Infructescence Type 6

( Figure 45 View FIGURE 45 )

Description. Laterally compressed spherical infructescence, 6 mm in diameter. Peduncle incomplete, 5 mm long and 1 mm wide, covered with trichomes. Individual fruit about 1 mm in diameter, with persistent perianth parts; a depression present on each fruit.

Claiborne Infructescence Type 7

( Figure 46 View FIGURE 46 )

Description. Main axis 24 mm long and 0.5–1 mm wide, dichotomously branching once to give rise to two branches, each ca 12 mm long and 0.6 mm wide; each dichotomously branching once more to give rise to four ultimate axes, each bearing one aggregate globose fruit ca 3.5 mm in diameter. At least four seeds in each fruit, ca. 1–1.5 mm in diameter, attached at a central point.

Number of specimens examined. 1. UF15738- 060633.

Remarks. The specimen may represent a determinate infructescence such as a raceme. The two lateral branches may represent the pedicels of fruits.

Angiosperm Incertae Sedis - Fruits and Seeds

Kingdom

Plantae

Phylum

Tracheophyta

Class

Magnoliopsida

Order

Apiales

Family

Araliaceae

Genus

Paleopanax

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