Fruits of an “Old World” tribe (Phytocreneae; Icacinaceae) from the Paleogene of
North and South America
Author(s): Gregory W. Stull, Fabiany Herrera, Steven R. Manchester, Carlos Jaramillo, and Bruce H.
Tiffney
Source: Systematic Botany, 37(3):784-794. 2012.
Published By: The American Society of Plant Taxonomists
URL: http://www.bioone.org/doi/full/10.1600/036364412X648724
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Systematic Botany (2012), 37(3): pp. 784–794
© Copyright 2012 by the American Society of Plant Taxonomists
DOI 10.1600/036364412X648724
Fruits of an “Old World” tribe (Phytocreneae; Icacinaceae) from the Paleogene
of North and South America
Gregory W. Stull,1,4 Fabiany Herrera,1,2 Steven R. Manchester,1 Carlos Jaramillo,2 and Bruce H. Tiffney3
1
Florida Museum of Natural History and Department of Biology, University of Florida, Gainesville, Florida 32611, U. S. A.
2
Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Balboa, Ancón, República de Panamá.
3
Department of Earth Science, University of California, Santa Barbara, California 93106, U. S. A.
4
Author for correspondence (gwstull@ufl.edu)
Communicating Editor: Mark P. Simmons
Abstract—The Phytocreneae (Icacinaceae) are a tribe of scrambling shrubs and lianas presently distributed in tropical Africa, Madagascar,
and Indo-Malesia. We describe the oldest known fossils of this tribe and provide the first recognition of this group in the Neotropical fossil record
based on distinctive fruit remains. Palaeophytocrene piggae sp. nov., from the late Paleocene of western North America, and Palaeophytocrene
hammenii sp. nov. and cf. Phytocrene sp., from the middle-late Paleocene of Colombia, constitute the oldest confirmed records of this tribe.
Pyrenacantha austroamericana sp. nov., from the Oligocene of Peru, represents an extant Old World genus known also from the Eocene fossil
record of North America and Europe. Collectively, these fossils indicate that the Phytocreneae were previously established in the Neotropics,
despite their current absence from the region, and may provide evidence for Paleogene floristic exchange between North and South America.
Keywords—Biogeography, fossil endocarps, Icacinaceae, Neotropics, Paleogene.
The Icacinaceae are a pantropical family within the Lamiidae
(Soltis et al. 2011) consisting of trees, shrubs, and woody
climbers. As currently circumscribed (Kårehed 2001; Lens
et al. 2008), the family contains 35 genera and 150 species
divided among four informal groups: the Icacina, Apodytes,
Cassinopsis, and Emmotum groups. Although these groups
probably do not together form a monophyletic assemblage,
the Icacina group itself is strongly supported in molecular
and morphological phylogenetic analyses as monophyletic
(Kårehed 2001; Lens et al. 2008). This clade, which is predominantly Paleotropical today, includes all of the genera of the
traditional tribes Iodeae, Phytocreneae, and Sarcostigmateae,
and some of the genera of the traditional tribe Icacineae (tribes
sensu Engler 1893; Sleumer 1942). Relationships within the
Icacina group remain poorly understood, but it appears that,
of the tribes within this clade, perhaps only the Phytocreneae
are monophyletic (Kårehed 2001; Lens et al. 2008).
The Phytocreneae (Engler 1893; Sleumer 1942), which consist
of the lianescent genera Chlamydocarya Baill. (five species),
Miquelia Meisn. (eight species), Phytocrene Wall. (12 species), Pyrenacantha Wight (30 species), and Polycephalium
Engl. (two species), occur today in lowland tropical forests
of Africa, Madagascar, and Indo-Malesia (Sleumer 1971; Fig. 1).
Fruits of this group are easily recognized and well documented
in the fossil record (Fig. 1) due to the distinctive features
of their endocarps, including deeply pitted outer surfaces
formed by tuberculate indentations, which, in all genera
except Phytocrene, penetrate into the locule, and transversely
oriented, interlocking undulate to digitate cells making up
the endocarp wall (Reid and Chandler 1933; Villiers 1973;
Manchester 1994; Potgeiter and van Wyk 1994). Fossils of
the Phytocreneae are well represented in the Paleogene of
Europe (Reid and Chandler 1933) and North America (Crane
et al. 1990; Manchester 1994; Rankin et al. 2008; Stull et al.
2011), suggesting that they were an important element of
mid-latitude forests during the warm interval of the early
Paleogene. Younger occurrences of Phytocreneae (Pyrenacantha
and Chlamydocarya) are also known from the Oligocene Fayum
flora of Egypt (Manchester and Tiffney 1993), indicating that
this group has been present in tropical forests of Africa for at
least 30 Ma. To date, the tribe has not been recognized in the
fossil record of the Neotropics.
In this paper, we describe the oldest known fossils of this
tribe and provide the first recognition of this group in the
Neotropical fossil record. Palaeophytocrene piggae sp. nov.,
based on endocarps from the late Paleocene (58 Ma) of
western North America, and Palaeophytocrene hammenii sp. nov.
and cf. Phytocrene, from the middle-late Paleocene of Colombia
(60–58 Ma), represent the oldest known fossil records of this
tribe (Fig. 2). Pyrenacantha austroamericana sp. nov., a carbonatepermineralized endocarp from the late early Oligocene of
Peru (30–28.5 Ma), represents an extant genus also known
from the Eocene fossil record of North America and Europe
(Fig. 3). These fossils provide important information on the
geographic history of this group, indicating that it was previously established in the Neotropics, despite its current
absence from the region. The presence of Palaeophytocrene
and Pyrenacantha in both North and South America may
also reflect a broader pattern of floristic exchange between
these regions during the Paleogene (Jaramillo and Dilcher
2001; Pennington and Dick 2004; Herrera et al. 2011).
Materials and Methods
Geological Settings—Palaeophytocrene piggae is based on endocarps
from several localities in the Paleocene of the Great Plains of western
North America. Two permineralized specimens were collected from the
Almont locality, Morton County, North Dakota (Sentinel Butte Formation), which is considered late Paleocene (58 Ma) in age (Crane et al.
1990; UF loc. 15722, 46 550 12.8600 N, 101 300 17.4000 W). Another permineralized specimen was recovered from Beicegel Creek, McKenzie County,
North Dakota (UF loc.18907, 47 21.9090 N, 103 25.4250 W). The other
specimens, which consist of endocarp impressions, casts, and molds,
were collected from the Fort Union Formation in Montana and Wyoming.
Brown (1962, pl. 67, Fig. 26) figured a specimen as “impression of a seed
showing pits arranged in longitudinal rows” from Lebo Creek, Montana
(USGS loc. 4618), and listed the same taxon from Sand Creek, 7 miles N.
of Glenrock, Wyoming (USGS loc. 8551). Additional Fort Union Formation
occurrences are Sand Draw (USGS loc. 9532, 42 48.0490 N, 108 10.9680 W),
Hells Half Acre (UF loc. 15740D, 43 01.020 N, 107 04.660 W), Leffingwell
Bluff (UF loc. 15776, 43 18.420 N, 105 02.090 W), and Linch (UF loc. 18255,
43 38.020 N, 106 12.320 W) in Wyoming, and Traub Ranch (USGS loc. 8910,
45 9.3440 N, 105 41.5930 W) in southeastern Montana. These fossils are
stored at the Florida Museum of Natural History (UF), the Field Museum
(PP), and the Smithsonian Institution (USNM). Although Crane et al.
(1990) previously reported several of these fossils, they did not formally
name or describe the species; here we provide a full treatment of these
stratigraphically significant records.
784
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STULL ET AL.: FOSSIL PHYTOCRENEAE FROM NORTH AND SOUTH AMERICA
785
Burnham and Johnson 2004), a reassessment of the age based on diatom
assemblages in the fossiliferous matrix (Manchester et al. in press) indicates that the site is late early Oligocene (30–28.5 Ma). The specimen is
housed at UF.
Systematic Comparisons—Other fossil and modern fruits of Phytocreneae
were investigated to provide a context for comparative systematic evaluation (Table 1; Appendix 1). Modern species representing all extant genera of Phytocreneae were studied from the herbaria A, MO, UC, and
WAG. The other fossil representatives studied include all of the four
genera of the tribe currently known from the fossil record (Chlamydocarya,
Palaeophytocrene, Phytocrene, and Pyrenacantha) (Table 1; Appendix 1). The
major fruit morphological characters examined are listed in Table 1. The
fossil and modern fruits were photographed with Nikon and Pentax SLR
digital cameras. For higher magnification, specimens were imaged using
a Zeiss STEMI SV8 dissecting microscope fitted with a Canon Powershot
A640 camera.
Taxonomic Treatment
Palaeophytocrene piggae Stull, sp. nov.—TYPE: U. S. A.
North Dakota: Sentinel Butte Formation (late Paleocene),
Almont, 46 550 12.8600 N, 101 300 17.4000 W (holotype, here
designated: UF 15722–22298).
Endocarp elliptic, unilocular, 7–10 mm long, 4–7 mm wide,
with a slight bulge on one side at the apical end. Endocarp
surface covered with numerous, evenly spaced pits arranged
in five to seven longitudinal rows, with approximately six pits
in each row. Pits formed by small, conical, tuberculate extensions into the locule. Tubercles 0.15–0.25 mm long, 0.25–
0.5 mm in diameter, extending shallowly into the locule.
Endocarp wall 0.20 mm thick. Figure 2A–F.
Fig. 1. Temporal and geographic distribution of Phytocreneae. Present distribution based on Sleumer (1942, 1971); fossil distribution based
on Reid and Chandler (1933), Manchester and Meyer (1987), Crane et al.
(1990), Manchester and Tiffney (1993), Manchester (1994), Rankin et al.
(2008), Stull et al. (2011), Collinson et al. (2012), and this paper. IndoMalesia is a biogeographic region including India, Indochina, and Malesia
(with Malesia comprising the Malay Peninsula, the Malay Archipelago,
New Guinea, and the Bismarck Archipelago). The genus Phytocrene might
also be represented in the Paleocene of South America (based on cf.
Phytocrene sp., informally described here).
Palaeophytocrene hammenii is based on single cast with an adhering
carbonized wall, collected from the recently discovered middle-late
Paleocene (60–58 Ma) Bogotá flora of Colombia (Herrera et al. 2011).
The locality outcrops in the Checua clay pit near the town of Nemocón in
the state of Cundinamarca (STRI loc. FH0806, 5 0.80 14.5N, 73 500 80.200 W).
Other plant remains found at this site include Annonaceae, Fabaceae,
Malvaceae, and Menispermaceae. This fossil is stored in the paleontological collections of the Colombian Geological Institute (INGEOMINAS) in
Bogotá, Colombia.
The species referred to as cf. Phytocrene sp. is based on an endocarp
compression from the middle-late Paleocene (60–58 Ma) Cerrejón Formation from northern Colombia (Wing et al. 2009; STRI loc. FH0322, Pit
Tabaco, Cesar-Rancheria basin, Guajira peninsula, 11 10 N, 72 50 W). Other
plant remains from this site include representatives of Araceae, Arecaceae,
Fabaceae, Lauraceae, Malvaceae, and Menispermaceae (Doria et al. 2008;
Herrera et al. 2008; Gomez-Navarro et al. 2009; Carvalho et al. 2011). This
fossil is stored in the paleontological collections of the Colombian Geological Institute (INGEOMINAS) in Bogotá, Colombia.
Pyrenacantha austroamericana is described based on a single carbonatepermineralized endocarp recently collected from the Belén fruit and
seed locality of northern coastal Peru. The Belén locality (UF loc. 603,
4 44.9660 S, 81 14.219 0 W), which was first reported by Berry (1927,
1929), is located in the desert area of northwestern Peru, 13 miles south
of Talara, in the Piura Region. The locality contains an abundance of
carbonate-permineralized fruits and seeds, representing taxa such as
Anonaspermum (Annonaceae); Leea, Cissus, and Ampelocissus (Vitaceae);
and Duckesia and Vantanea (Humiriaceae). Although formerly considered
early Eocene in reviews of South American paleofloras (Romero 1986;
Additional Specimens Studied—PP 33791 from Almont (UF loc. 15722),
UF 53529 from Beicegel Creek (UF loc. 18907), UF 35281 from Leffingwell
Bluff (UF loc. 15776), UF 23051 from Hell’s Half Acre (UF loc. 15740D),
UF 35282 from Linch (UF loc. 18255), USNM 545432 from Sand Draw
(USGS loc. 9532), USNM 545703 from Traub Ranch (USGS loc. 8910),
USNM 545704 from Lebo Creek (USGS loc. 4618), and USNM 545705
from Sand Creek (USGS loc. 8551).
Comments—This species is based on ten endocarps from
several localities of the Fort Union and Sentinel Butte Formations (see Materials and Methods). Most of the fossils are
compressions or impressions, revealing the pitting pattern
on the endocarp surface and/or protrusions into the locule.
Three specimens, from Almont and Beicegal Creek, North
Dakota, are permineralized portions of endocarps, revealing
the topography of the locule surface as well as the outer
endocarp surface. On one of these permineralized specimens
the tubercles are mostly broken, revealing sediment in-fillings
of the tubercle channels, which correspond to the pits on the
endocarp surface (Fig. 2A).
Etymology—The specific epithet, piggae, is established in
honor of Kathleen B. Pigg, recognizing her contributions to
paleobotany including the study of Icacinaceae in the Paleocene of North America.
Systematic Affinity—Endocarps of Phytocreneae show a
suite of features consistent with the fossil specimen described
here. They are unilocular, elliptic-ovoid, and possess pits on
the outer surface created by the hollow core of tuberculate protrusions of the endocarp wall into the locule. These
characters provide strong evidence for placement within the
Phytocreneae. Although distinct from Polycephalium, Pyrenacantha,
and Chlamydocarya, which possess cylindrical, spiny, or vertically elongate tubercles, and from Phytocrene, which has protrusions that terminate before the locule, these fossils show
similarities with two genera of this tribe: the extant genus
Miquelia (Fig. 4) and the fossil genus Palaeophytocrene. Endocarps of extant Miquelia show mound-like or sloping, rather
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SYSTEMATIC BOTANY
[Volume 37
Fig. 2. Paleocene endocarps of Phytocreneae from western North America and Colombia. A–F. Palaeophytocrene piggae Stull, sp. nov. A.
Permineralized endocarp showing the locular surface, UF 22298 holotype; UF loc. 15722. B. Same as A, PP 33791 (UF loc. 15722). C. Impression of the
dorsal or ventral endocarp surface, USNM 545703 (USGS loc. 8910). D. Impression of endocarp surface, USNM 545432 (USGS loc. 9532). E. Endocarp
compression, showing the pitted external surface, UF 23051 (UF loc. 15740D). F. Fossil from A in cross section, showing the endocarp wall and
tubercluate extensions into the locule (indicated by arrows). G–H. cf. Phytocrene sp, STRI 9959 (STRI loc. FH0322). G. Transverse section of the fossil
from H, showing the termination of the pits before the locule (indicated by arrows). H. Endocarp compression, showing the pitted external surface. I–K.
Palaeophytocrene hammenii Stull, sp. nov., STRI 12832 holotype; STRI loc. FH0806. I. Fractured endocarp cast showing the morphology of the locule surface
and remnant carbonized endocarp wall. J. Close-up view of the conical tubercules lining the locule surface. K. Counterpart of the endocarp cast shown in
I. Scale bars: A–E, H = 5 mm; F = 0.5 mm; G, J = 1 mm; I, K = 2 mm.
2012]
STULL ET AL.: FOSSIL PHYTOCRENEAE FROM NORTH AND SOUTH AMERICA
787
Fig. 3. Pyrenacantha austroamericana Stull, sp. nov., UF 54804 (holotype; UF loc. 603). A, B. Opposite lateral faces of the endocarp, showing the finely
pitted surface. C, D. Transverse views of the endocarp, showing the spiny tuberculate extensions into the locule. E, F. Enlarged transverse views,
showing hollow tubercle channels leading to pits on the endocarp surface. Scale bars: A, B, C, D = 5 mm; E, F = 1 mm.
than parallel-sided, tubercles (Reid and Chandler 1933; Rankin
et al. 2008; Fig. 4F, L). Such conical tubercles, which are also
shown in the fossils described here (Fig. 2F), have been considered an important feature for distinguishing between
Miquelia and Palaeophytocrene, a genus established for fossil
endocarps with pitted surfaces and broad, parallel-sided tubercles (Reid and Chandler 1933). However, numerous fossils
placed in Palaeophytocrene, including P. ambigua described by
Reid and Chandler (1933), show tubercle morphologies ranging from parallel-sided to conical. For example, P. manchesteri
Rankin, Stockey & Beard (2008) was described as having
conical tubercles, whereas P. cf. pseudopersica Scott (Rankin
et al. 2008) has tubercles ranging from conical to parallel sided,
and P. hancockii Scott (Scott 1954; Manchester 1994) has distinctly parallel-sided tubercles. In addition to this overlap
in tubercle morphology, both Palaeophytocrene and at least
some species of Miquelia appear to have micropapillate locule
linings (Rankin et al. 2008; Fig. 4L). However, endocarps of
Palaeophytocrene have relatively evenly spaced pits and usually
lack reticulate ridging, whereas the fruits of Miquelia that we
examined (Appendix 1) show more clustering of the pits, and
have a reticulum of ridges on the endocarp surface (Fig. 4A,
B, G, H). Palaeophytocrene vancouverensis, however, appears to
possess a reticulum of ridges on its endocarp surface (Rankin
et al. 2008). Clearly a re-evaluation of Palaeophytocrene with
greater reference to modern fruits of Miquelia, as well as other
genera of Phytocreneae, will be necessary to better delimit this
fossil genus and understand its relation to modern taxa of this
tribe. Because the fossils described here fit within the morpho-
logical range of previously described fossils of Palaeophytocrene,
it seems appropriate to place the species within Palaeophytocrene,
as this genus has functioned as a general repository for pitted
and shortly tuberculate endocarp fossils distinct from those
of the modern genera. The approach is also adopted for the morphologically similar fossil from Colombia described below.
Palaeophytocrene piggae is distinct from other species of
Palaeophytocrene in terms of size and number of surface pits;
most previously described Palaeophytocrene species are larger
than 10 mm in length and show a greater number of surface
pits (e.g. 10–20 surface pits spanning the length vs. six pits in
P. piggae). Palaeophytocrene manchesteri and P. pseudopersica
(Rankin et al. 2008; Manchester 1994), which match the size
range of P. piggae (Table 1), have a greater density of surface
pits, and have larger tubercles than those of the fossil described
here. Palaeophytocrene piggae differs from P. hammenii sp. nov.,
described below, in having considerably shorter tubercles and a
more elongated apical end. Palaeophytocrene piggae differs from
the Cerrejón fossil, cf. Phytocrene sp., described below, in having
tubercles that extend into the locule; in the Cerrejón specimen,
the pits or tubercles terminate before the locule cavity.
Palaeophytocrene hammenii Stull, sp. nov.—TYPE:
COLOMBIA. Cundinamarca: Bogotá flora (middle-late
Paleocene, Bogotá Formation), Checua clay pit, 5 0.80 14.500 N,
73 500 80.200 W (holotype, here designated: STRI 12832).
Endocarp elliptic, unilocular, 5 mm long, 3.25 mm wide.
Inner surface of endocarp wall showing numerous tubercles,
which are represented by pits on the external endocarp surface.
788
SYSTEMATIC BOTANY
[Volume 37
Table 1. Comparative morphology of modern and fossil Phytocreneae fruits. Data assembled from the following sources: Reid and Chandler
(1933), Sleumer (1971), Manchester (1994), Rankin et al. (2008), and personal observations of the specimens listed in Appendix 1. All measurements are
in millimeters. Authorities for binomials indicated in Appendix 1. Under the category Endocarp surface, “ridged” indicates the presence of an
ornamentation of ridges on the endocarp surface, in addition to pits, whereas “smooth” refers to the absence of such surface ridging.
Taxon
1. Chlamydocarya macrocarpa
2. Chlamydocarya thomsoniana
3. Chlamydocarya sp.
4. Miquelia caudata
5. Miquelia celebica
6. Polycephalium capitatum
7. Pyrenacantha acuminata
8. Pyrenacantha kaurabasana
9. Pyrenacantha occidentalis
10. Pyrenacantha repanda
11. Pyrenacantha austroamericana
sp. nov.
12. Pyrenacantha staudtii
13. Pyrenacantha sylvestris
14. Pyrenacantha sp.
15. Palaeophytocrene ambigua
16. Palaeophytocrene foveolata
17. Palaeophytocrene hammenii
sp. nov.
18. Palaeophytocrene hancockii
19. Palaeophytocrene manchesteri
20. Palaeophytocrene piggae
sp. nov.
21. Palaeophytocrene cf.
pseudopersica
22. Palaeophytocrene
vancouverensis
23. cf. Phytocrene sp.
Distribution or fossil locality
Endocarp length
West Africa
Central/West Africa
Oligocene Fayum flora, Egypt
Malesia
Malesia
West Africa
Central/West Africa
East Africa
Eocene Clarno Nut
Beds flora, Oregon
Philippines
Oligocene Belen flora, Peru
Pitted/ridged
Pitted/ridged
Pitted/unknown
Pitted/ridged
Pitted/ridged
Pitted/smooth
Pitted/smooth
Pitted/smooth
Pitted/smooth
20.25
12
27
17
16
9.5
11.5
13.5
25–33
Pitted/smooth
Pitted/smooth
23.5
20 (estimation)
Central Africa
Central Africa
Oligocene Fayum flora, Egypt
Eocene London Clay flora, England
Eocene London Clay flora, England
Paleocene Bogotá flora, Colombia
Pitted/smooth
Pitted/smooth
Pitted/smooth
Pitted/smooth
Pitted/smooth
Pitted/unknown
13.5
8.75
30
22
15–27
5
Eocene Clarno Nut
Beds flora, Oregon
Eocene Appian Way,
British Columbia
Paleocene Fort Union Group,
western North America
Eocene Appian Way,
British Columbia
Eocene Appian Way,
British Columbia
Paleocene Cerrejón flora, Colombia
Pitted/smooth
38.5–85.0
Pitted/smooth
7.2
Pitted/smooth
7–8
Pitted/smooth
At least 9.8
Pitted/ridged
19.5
Pitted/ridged
5.5
Endocarp
width
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Endocarp surface
(pitted/ridged or smooth
15
7.5–10
19
11.25
7.25
7
8
10.25
15.7
30
At least 11.5
9.5
9
15
14.5
14–17
3.25
26.9–50.0
5.3
4–5
7.5–11.0
12.5
4.0
Endocarp
thickness
0.6
0.5
Unknown
0.25–0.5
0.25–0.5
0.25–0.5
0.5
0.35
1.0
0.25
0.25
0.25–0.5
0.25
Unknown
1.0–1.2
Unknown
Unknown
2.0–2.3
0.1–0.3
0.25
0.7–1.0
1.5–2.1
0.2
Tubercles more or less conical, 0.5–0.75 mm in length, 0.5 mm
in diameter, arranged in five longitudinal rows, with up to
six tubercles per row. Figure 2I–K.
Comments—This species is based on a single carbonized
endocarp retaining the three-dimensionality of the original
fruit. The endocarp is fractured, showing tubercles lining the
locule wall. Several tubercles are broken, revealing sediment-
Pit number
(in length)
Pit number
(in width)
Tubercle
shape
Tubercle
length
Tubercle
diameter
8
8–10
Unknown
9
11
12
15
20–25
16–19
20–25
At least 20
9
9
20–25
8–9
12
6
13–14
12
6
At least 8
12
7
8
8–10
Unknown
6
7
6
12
15
12–14
11–13
11–13
6–7
9
15
4–5
8
5
9
9
5
8
6–7
6
Elongate plates
Elongate plates
Elongate plates
Conical
Shallowly conical
Peg-shaped
Thin, tapering
Peg-shaped
Cylindrical
Spine-shaped
Spine-shaped
Cylindrical to plate-like
Peg-shaped to plate-like
Cylindrical
Conical
Cylindrical
Conical
Cylindrical
Conical
Conical
Cylindrical
Cylindrical-conical
Absent
1.75
0.75
1–2
0.5–0.75
0.5
0.5–0.75
1.25–1.5
0.5–0.75
4.5–5.2
0.75
1.0
1.5–2.0
1
Unknown
Unknown
0.7–1.0
0.5–0.75
2.0–3.5
0.5–0.75
0.15–0.25
1.4–1.8
2.0–2.7
N/A
0.75–1.0
0.5–0.75
1.0–1.5
1.0–1.25
1.0–1.5
0.25
0.25
0.25
1.0
0.15–0.25
0.25
0.5–0.75
0.5
0.8
0.3–0.5
0.2–0.4
0.5
2.2
0.2–0.4
0.25–0.5
0.6–1.0
0.8–1.4
N/A
filled channels within that correspond to pits on the endocarp external surface.
Etymology—The specific epithet, hammenii, is established
in honor of the late paleobotanist Thomas van der Hammen,
who worked extensively toward the advancement of paleobotany in Colombia and the preservation of modern
Andean forests.
2012]
STULL ET AL.: FOSSIL PHYTOCRENEAE FROM NORTH AND SOUTH AMERICA
789
Fig. 4. Modern endocarps of Miquelia. A–F. Miquelia caudata King (King 7621). A. Lateral view. B. Dorsal view. C. Basal view. D. Apical view. E.
Transverse view. F. Close-up of the endocarp wall, showing the conical tubercles. G-L. Miquelia celebica Blume (Ramos and Edano 49155). G. Lateral view.
H. Dorsal view. I. Apical view. J. Basal view. K. Transverse view. L. Close-up of a single, shallowly sloping tubercle covered in papillae. Scale bars: A, B,
E, G, H, K = 5 mm; C, D, F, I, J = 3 mm; L = 1 mm.
Systematic Affinity—Palaeophytocrene hammenii is similar
to P. piggae (described above). The endocarps of both species
are relatively small (5–10 mm in length), and show surface
pits arranged in longitudinal rows, with approximately five
pits spanning the width of the endocarp and six pits spanning the length. Palaeophytocrene hammenii differs, however,
in having longer tubercles that extend more deeply into the
locule. Additionally, P. piggae has a more distinctly elongate
apical end compared to this Colombian fossil. Therefore,
despite morphological similarity with P. piggae, these differences support recognition of the Colombian fossil as a distinct species.
Systematic Affinity—Phytocrene is unique among the genera of Phytocreneae in having pits or tubercles that do not
extend into the locule cavity. This character, which has proved
useful in distinguishing fossils of Phytocrene from other members of this tribe (Stull et al. 2011), is also present in the fossil
illustrated here, suggesting affinities between the Cerrejón
specimen and this extant genus. However, the fossil is considerably smaller than the modern Phytocrene fruits we have
examined. Additionally, unlike fruits of Phytocrene, the fossil
illustrated here is possibly bivalved. Given these differences,
and the limited number of modern Phytocrene fruits we have
been able to study, we hesitate to place the fossil in this genus.
cf. Phytocrene sp. COLOMBIA. Guajira Peninsula: Cerrejón
flora (middle-late Paleocene, Cerrejón Formation),
Cesar-Rancheria basin, Pit Tabaco, 11 10 N, 72 50 W (ING
0857/STRI 9959).
Endocarp elliptic, unilocular, 5.5 mm long, 4.0 mm wide.
Surface covered with numerous pits, 7 pits in length and
6 pits in width, that do not penetrate the locule. The pit
diameters generally decrease toward the margin of the endocarp. Pits encircled by slight ridges. Endocarp wall 0.2 mm
thick. Figure 2G, H.
Comments—Only one fossil of this kind was recovered
from the Cerrejón flora. It is a fragmentary, carbonized endocarp compression. The fossil represents a complete lateral
endocarp half, suggesting that the original endocarp was
bivalved; this is also suggested by the pitting pattern, which
shows larger pits toward the center of the endocarp half and
smaller pits along the margin. From the surface appearance (Fig. 2H), this fossil was first thought to represent
Palaeophytocrene hammenii. However a transverse section
(Fig. 2G) revealed that the tuberculate formations do not
extend into the locule (Fig. 2G), an important difference from
P. hammenii and Palaeophytocrene in general.
Pyrenacantha austroamericana Stull, sp. nov.—TYPE: PERU,
Piura: Belén flora (late early Oligocene), 4 44.9660 S,
81 14.2190 W (holotype, here designated: UF 603–54804).
Endocarp unilocular, elliptical to ovoid overall (extrapolation from incomplete specimen), lenticular in transverse section, 20 mm long (estimated based on the curvature of the
of the incomplete specimen, which is 10 mm in length), at
least 11.5 mm wide, 4.25 mm thick; surface covered with
small pits (0.15–0.25 mm in diameter), pits regularly spaced
(0.75–1.0 mm apart, except near base, where they are more
densely spaced). Width of endocarp spanned by 12 pits
(counted at the middle of the endocarp), length spanned by
30 pits (twice the number counted from the partial specimen). The pits are the surface expression of elongate tubercles
that penetrate the locule. Tubercles 1 mm long, 0.25 mm in
diameter at the base, and tapering distally to a point. Each
tubercle possesses a hollow inner channel leading to a pit on
the external endocarp surface. Endocarp wall relatively thin
(0.25 mm). Figure 3.
Comments—This species is based on a single, fragmentary
carbonate-infiltrated endocarp lacking cellular preservation.
Although the specimen represents only the basal half of the
790
SYSTEMATIC BOTANY
fruit, the endocarp morphology is well preserved, showing
the pitted external surface, the thickness of the endocarp
wall, and the tuberculate extensions into the locule.
Etymology—The specific epithet, austroamericana, with the
Latin derivation meaning literally “South America,” emphasizes the geographic source, which is well outside the modern geographic range of the genus.
Systematic Affinity—The suite of features shown by this
fossil is consistent with that of Phytocreneae endocarps in
general (e.g. unilocular, elliptic, with pitted outer surfaces
and tuberculate protrusions into the locule). Of the genera of
Phytocreneae, the Peruvian fossil shows strongest similarity
to Pyrenacantha. Most extant species of Pyrenacantha possess
smooth endocarp surfaces covered with small, densely spaced
pits of the kind seen in this fossil (e.g., Fig. 5B). Endocarp
surface pits of other genera are wider in diameter (Phytocrene,
Miquelia, and Palaeophytocrene), longitudinally oriented and
encircled by ridge-like structures (Chlamydocarya; Fig. 5M),
or irregularly spaced (Polycephalium; Fig. 5K). Also, like the
Peruvian fossil, Pyrenacantha can have spiny or tapering
tubercles, circular in transverse section, that extend into the
locule cavity (Fig. 5D, E). This tubercle type is not found in
any other genus of Phytocreneae. Tubercles of Miquelia are
larger in diameter and shallowly conical (Reid and Chandler
1933; Rankin et al. 2008; Fig. 4F); those of Phytocrene do not
[Volume 37
penetrate the locule or do so only slightly, appearing as low
mounds (Reid and Chandler 1933; Rankin et al. 2008); those
of Chlamydocarya are vertically elongate and plate-like (Fig. 5O);
those of Polycephalium are peg-shaped (Fig. 5L); and those of
Palaeophytocrene are typically much broader than the tubercles found in Pyrenacantha (Reid and Chandler 1933) and the
other modern genera we have observed. Although a few species of Pyrenacantha show peg-shaped tubercles resembling those of Polycephalium (e.g. Pyrenacantha kaurabassana),
no members of Polycephalium are known to possess the fine,
densely spaced surface pits, corresponding to spiny tubercles,
found in certain members Pyrenacantha. Therefore, we place
the Peruvian fossil in the genus Pyrenacantha.
Among the modern species of Pyrenacantha examined,
including specimens from Africa and Indo-Malesia, the Peruvian fossil is most morphologically similar to endocarps of
P. repanda, of the Philippines (Sleumer 1971), and P. volubilis,
which occurs in Cambodia, India, Sri Lanka, Vietnam, and
the Hainan Province of China (Hua and Howard 2008). Endocarps of these species, like the fossil, possess small surface pits
corresponding to spine-shaped tubercles that extend one mm
into the locule (Hua and Howard 2008). The African species
examined differ in having tubercles that are more elongate and
cylindrical (P. staudtii), peg-shaped (P. kaurabassana), or thin and
tapering to a hair-like apical strand (P. vogeliana, P. acuminata).
Fig. 5. Modern endocarps of Pyrenacantha, Polycephalium, and Chlamydocarya. A–E. Pyrenacantha repanda Merr. (Elmer 17359). A. Lateral view of fruit
with exocarp remaining. B. Lateral view of sectioned endocarp (exocarp removed). C. Dorsal view. D. Transverse view. E. Close-up of the endocarp wall
and the spiny tubercles. F–G. Pyrenacantha kaurabasana Baill. (Reitsma 126). F. Lateral view. G. Transverse view. H–J. Pyrenacantha staudtii (Engl.) Engl.
(Breteler 2968). H. Lateral view. I. Transverse view. J. Close-up of the endocarp wall and tuberculate extensions (oblique lateral view). K–L. Polycephalium
lobatum (Pierre) Pierre ex Engl. (Bokdam 3062). K. Laterial view. L. Transverse view. M–O. Chlamydocarya macrocarpa A. Chev. ex Hutch. (Koning 1058).
M. Lateral view. N. Transverse view. O. Close-up of the vertically elongate tubercles (oblique lateral view). Scale bars: A–D, F–I, K, L, N = 5 mm; E = 1 mm;
J, O = 2 mm; M = 10 mm.
2012]
STULL ET AL.: FOSSIL PHYTOCRENEAE FROM NORTH AND SOUTH AMERICA
Compared to other known fossils of Pyrenacantha, the
Peruvian fossil is clearly distinct. Pyrenacantha occidentalis
Manchester (1994), from the Eocene of Oregon, has cylindrical,
rather than spiny, tubercles that extend much farther into
the locule. Fossil endocarps of Pyrenacantha from the Oligocene of Fayum, Egypt, have peg-shaped tubercles (Manchester
and Tiffney 1993; also examined for this study), similar to
those of several modern African species (e.g. P. kaurabassana
and P. vitifolia), but distinct from the spine-shaped tubercles
of the species described here. Several specimens from the
Eocene of Messel, Germany (e.g. SM.B Me 7150; Collinson
et al. 2012) are similar in overall size and shape and in the
size and density of their surface pits. However, the inner
morphology of these Messel specimens has not yet been investigated, impeding more detailed comparison with the Peruvian fossil. Because the Peruvian fossil is geographically and
temporally isolated from modern members of Pyrenacantha,
and cannot be assigned to any previously described fossil species of this genus, it therefore warrants placement in a new
species, Pyrenacantha austroamericana.
Discussion
Fossil Record of the Phytocreneae—The Phytocreneae
are represented in the fossil record by three extant genera,
Chlamydocarya, Phytocrene, and Pyrenacantha, and the extinct
genus Palaeophytocrene (Fig. 1). Reid and Chandler (1933) also
placed the fossil genus Stizocarya, from the Eocene London
Clay Flora, in this tribe. Stizocarya was reported to have a
tuberculate wall structure (Reid and Chandler 1933), like the
other genera of this tribe, but there has been no subsequent
work to further refine its placement. An endocarp similar
to Chlamydocarya is known from the Oligocene of Egypt
(Manchester and Tiffney 1993). This fossil shows the lamellate tubercles characteristic of the modern endocarps of this
genus (Villiers 1973), but the lamellae are oriented at right
angles to the long axis of the endocarp rather than parallel to it.
Phytocrene is represented by two fossil species, P. densipunctata
(Stull et al. 2011) and P. punctilinearis (Collinson et al. 2012),
respectively from the Eocene of Tennessee, U. S. A., and the
Eocene of Messel, Germany. Investigation of specimens previously attributed to Phytocrene by Scott and Barghoorn
(1957) from the Cretaceous (Turonian) of New York revealed
that these Cretaceous fossils do not represent this modern
genus, or even the family Icacinaceae (Stull and Manchester,
unpublished observations). Hence the specimens from Tennessee
and Messel constitute the only confirmed fossil records for
this genus. If the Cerrejón specimen, described here, does
indeed represent Phytocrene, this would be the oldest record
of this extant genus. The Cerrejón fossil is considerably
smaller than Phytocrene fruits previously described from the
Eocene of North America and Europe, and therefore, if it
does represent Phytocrene, the Cerrejón fossil might not represent an immediate phylogenetic/biogeographic connection
to these other fossil taxa.
Pyrenacantha and Palaeophytocrene are known from numerous Paleogene localities in various geographic regions. Fossil
fruits of Pyrenacantha are known from the middle Eocene flora
of Messel, Germany (Collinson et al. 2012), the middle Eocene
Clarno Nut Beds of Oregon (Manchester 1994), and the Oligocene Fayum flora of Egypt (Manchester and Tiffney 1993).
Pyrenacantha austroamericana, described here from the Oligocene of Peru, represents the first report of this genus from the
791
Neotropics. As mentioned above, P. austroamericana is distinct from previously reported fossils of this genus and perhaps more morphologically similar to fruits of the modern
Indo-Malesian species, e.g. Pyrenacantha repanda. Several specimens from Messel, Germany are at least superficially similar
to P. austroamericana and deserve closer study, with focus on
the internal structure, particularly the tubercle configuration.
Palaeophytocrene has the oldest and most extensive fossil
record of the tribe, including reports from the early Eocene
London Clay flora (Reid and Chandler 1933), the middle Eocene of Messel, Germany (Collinson et al. 2012), the
middle Eocene of Oregon (Manchester 1994) and British
Columbia (Rankin et al. 2008), the Eocene Roslyn Formation
of Washington (Pigg and Wehr 2002), and the early Oligocene
of Oregon (Manchester and Meyer 1987). The oldest fossils of
Palaeophytocrene, and of tribe in general, are those described
here from the middle-late Paleocene (60–58 Ma) of western
North America and Colombia.
Judging from the rarity of Paleocene specimens, even at
well-collected sites, the Phytocreneae appear to have been a
minor, yet widespread, constituent of Paleocene floras (Crane
et al. 1990; and our observations); only a handful of fossils,
representing two species of Palaeophytocrene (and potentially
one species of Phytocrene), have been recognized from this
epoch. In contrast, the tribe is an abundant, relatively diverse,
and widespread constituent of Eocene floras (Reid and
Chandler 1933; Manchester 1994; Stull et al. 2011; Collinson
et al. i2012), including numerous species of Palaeophytocrene
as well as representatives of several modern genera (Phytocrene,
Pyrenacantha). This fossil record suggests that the tribe may
have radiated in response to the expansion of warm biomes
during the early Eocene, when global temperatures reached
their Cenozoic maximum (Zachos et al. 2001; Wing et al. 2005).
A similar pattern of diversification at this time is exhibited by
members of the Iodeae (Pigg et al. 2008) as well as other, nonicacinaceous taxa, such as Menispermaceae (Jacques 2009),
Sabiaceae (Reid and Chandler 1933; Crane et al. 1990;
Manchester 1994), and Vitaceae (Chen 2009).
Biogeographic Implications—Today, the Phytocreneae occur
in tropical Africa, Madagascar, and Indo-Malesia (Sleumer
1971). Although there have been numerous reports of this
tribe from the Paleogene of North America and Europe (e.g.
Reid and Chandler 1933; Manchester 1994; Rankin et al. 2008;
Stull et al. 2011), suggesting that it was an important element
of mid-latitude forests of these continents during times of
warmer climate, previously there has been no indication that
the Phytocreneae ever occurred in the Neotropics. Pyrenacantha
austroamericana, Palaeophytocrene hammenii, and cf. Phytocrene sp.
offer the first reliable paleobotanical evidence of this tribe in
South America, expanding our understanding of the historical
distribution of this group. These fossils, ranging in age from
middle-late Paleocene to late early Oligocene (60–30 Ma), also
suggest that the Phytocreneae were present in the Neotropics
throughout much of the Paleogene. The point at which the
tribe was extirpated from South America is uncertain.
The presence of Pyrenacantha in northern Peru during the
late early Oligocene (30–28.5 Ma) suggests a drastic difference in climate compared with modern conditions, given that
the genus occurs today mostly in humid tropical forest (Labat
et al. 2006), whereas this part of Peru is currently extremely
dry, a product of both the cool Humboldt current (Ravelo 2006)
and the rain-shadow of the Andes. Pyrenacantha austroamericana,
along with some other co-occurring fossils like Ampelocissus,
792
SYSTEMATIC BOTANY
Duckesia, Vantanea, and Leea (Manchester et al. in press), suggest that the Belén area was much more humid during the
early Oligocene, either because the Andes mountains still
did not have a pronounced topographic relief (< 1,000 m)
(Garzione et al. 2008), or because the Humboldt current
was considerably reduced, or both. This paleobotanically
inferred paleoclimate corroborates climate models predicting
that a low topological relief for the Andes Mountains would
significantly increase sea surface temperature and precipitation in northern coastal Peru (Sepulchre et al. 2009). This
evidence challenges previous suggestions (Lamb and Davis
2003) that coastal northern Peru experienced an arid climate
during the late Paleogene.
Although the Phytocreneae occur today exclusively in
tropical Africa, Madagascar, and Indo-Malesia, there are several lines of evidence suggesting that these South American
fossils represent a Paleogene floristic connection with North
America, where the tribe was previously widespread and
diverse (Manchester 1994; Stull et al. 2011). The morphological similarity of the roughly contemporaneous species
Palaeophytocrene piggae and P. hammenii suggests that they
might be closely related taxa that diverged following migration between these continents. The presence of Pyrenacantha
in both North and South America during the Paleogene provides another potential floristic link between these regions
(in addition to the Paleocene occurrences of Palaeophytocrene),
and the observation that Pyrenacantha austroamericana is more
similar morphologically to the extant Indo-Malesian species
of this genus than to the extant African species also favors the
hypothesis of exchange via North America. If the Paleocene
fossil from Cerrejón, described here, does represent the genus
Phytocrene, this would constitute another South American
connection with a group distributed both in the fossil flora
of North America and the modern flora of Indo-Malesia; however, the affinities of this fossil with other modern and fossil
species of Phytocrene are ambiguous, limiting inferences of
biogeographic patterns.
Although the directionality of this potential North-South
America floristic connection is difficult to assess, the presence of Palaeophytocrene and Pyrenacantha in both North and
South America requires that at least two dispersal events
occurred between these continents during the Paleogene.
This fits with growing evidence (e.g. Jaramillo and Dilcher
2001; Pennington and Dick 2004; Herrera et al. 2011) that
floristic exchange between North and South America, particularly during the Paleogene, occurred more frequently than
previously thought (Burnham and Graham 1999). This phytogeographic exchange could have been favored when a
Caribbean volcanic arc briefly connected North and South
America during the Paleocene (Cardona et al. 2010; Bayona
et al. 2011), upon the first emergence of the Central American
arch during the middle to late Eocene (Montes et al. 2012),
or upon the emergence of the proto-Greater Antilles during
the late Eocene (Iturralde-Vinent and MacPhee 1999). Other
fossils supporting this floristic connection include fruits of
Palaeoluna (Menispermaceae) shared between the Paleocene
of Colombia and western North America (Herrera et al. 2011)
and multiple pollen taxa shared between Colombia and the
Gulf Coast of North America during the Paleocene-Eocene,
e.g. Bombacacidites nacimientoensis, Malvaceae s. l. (Carvalho
et al. 2011); Ulmoideipites krempii, Ulmaceae; Syncolporites
poricostatus, Myrtaceae; and Proxapertites operculatus, Araceae
( Jaramillo and Dilcher 2001).
[Volume 37
While Palaeophytocrene may have migrated to or from
South America before the late Paleocene, it is uncertain when
Pyrenacantha arrived in South America. The oldest fossil
records of Pyrenacantha are from the Middle Eocene of Europe
(Collinson et al. 2012) and North America (Manchester 1994),
suggesting that this genus may have originated in the
Northern Hemisphere and then migrated to South America
sometime between the Middle Eocene and Late Oligocene.
However, it cannot be ruled out that Pyrenacantha, and possibly the tribe in general, originated in the Neotropics and
then migrated northward during the early Paleogene. Future
paleobotanical work on Paleocene-Eocene deposits in South
America will be necessary to determine in more detail the
history of Pyrenacantha, and the Phytocreneae in general, in
the Neotropics.
The presence of a Paleogene floristic connection between
North and South America also has important broader implications for tropical plant historical biogeography. Early Tertiary floras of North America (Manchester 1999) show strong
taxonomic similarity with those of Europe (Reid and Chandler
1933; Collinson et al. 2012) and the modern flora of the Old
World tropics, particularly Indo-Malesia, suggesting that migration between North America and the Old World tropics,
via Europe, was frequent during the Paleogene (Tiffney
1985). If North America also had a floristic connection with
South America during this period, even if relatively weak, this
would have facilitated the exchange of taxa between the New
and Old World tropics. This may explain the presence of
“Old World” taxa in Paleogene floras of South America,
such as Phytocreneae (Icacinaceae; this paper), Leea (Vitaceae;
Manchester et al. in press), and Stephania (Menispermaceae;
Herrera et al. 2011), and point to an important historical
means by which tropical groups established pantropical distributions or New World-Old World disjunctions, as has been
suggested in previous studies based on paleobotanical data
(Herrera et al. 2011; Stull et al. 2011) and molecular dating
analyses (e.g. Davis et al. 2002).
The new species described here provide important information on the age and geographic history of the Phytocreneae.
Based on previous paleobotanical reports (e.g. Reid and
Chandler 1933; Manchester 1994; Stull et al. 2011), the tribe
was known to have extended into Europe and North America
during the Paleogene, despite its present confinement
to the Old World tropics. The fossils described here, which
include the oldest records for the tribe, indicate that the
Phytocreneae were present in South America as well as
North America and Europe during the Paleogene. Several
lines of evidence indicate that these South American fossils
represent direct floristic exchange with North America during the Paleogene, offering important broader implications
for the role of North America in shaping patterns of tropical
plant distribution.
Acknowledgments. We thank Jan Wieringa (WAG) for making modern icacinaceous fruits available for study, Terry A. Lott (UF) for assistance
with photography and proofreading, and Mark P. Simmons and
two anonymous reviewers for providing helpful suggestions for improving
the manuscript. This study was supported by graduate student research
awards from the American Society of Plant Taxonomists and the Society
of Systematic Biologists to G. W. Stull; the Evolving Earth Foundation, the
Geological Society of America Foundation, the Asociación Colombiana de
Geólogos y Geofı́sicos del Petroleo-ARES, the Gary S. Morgan Student
Research Award, and the Lewis & Clark Foundation-American Philosophical Society to F. Herrera; the Smithsonian Paleobiology Endowment
Fund, the Fundación para la Promoción de la Investigación y la Tecnologı́a,
2012]
STULL ET AL.: FOSSIL PHYTOCRENEAE FROM NORTH AND SOUTH AMERICA
Banco de la República, the Colombian Petroleum Institute, and Fundación
Ares to C. Jaramillo; and National Science Foundation grant BSR 0743474
to S. R. Manchester.
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Appendix 1. Modern and fossil fruits of Phytocreneae examined for
this study. For the modern fruit specimens, voucher information is in the
following sequence: taxon and authority, collector and number (herbarium acronym), country (number of fruit specimens examined). For the
fossil fruit specimens, information is listed as follows: taxon and authority, museum acronym and specimen number(s), age, and locality. Fossil
specimens not physically examined, but studied based on published
descriptions and photographs, are noted with an asterisk. Acronyms
of museums housing the fossil collections are as follows: UF (Florida
Museum of Natural History), UM (University of Michigan Museum of
Paleontology), NHM (Natural History Museum, London), UAPC-ALTA
(University of Alberta Paleobotanical Collections).
Modern fruits: Chlamydocarya macrocarpa A. Chev. ex Hutch. et Dalziel,
Koning 4918 (WAG), Ivory Coast (1); Chlamydocarya macrocarpa A. Chev.
[Volume 37
ex Hutch. et Dalziel, Koning 1058 (WAG), Ivory Coast (1); Chlamydocarya
thomsoniana Baill., Bos 5432 (WAG), Cameroon (1); Chlamydocarya thomsoniana
Baill., Koning 5275 (WAG), Ivory Coast (1); Miquelia celebica Blume, Ramos and
Edano 49155 (UC), Philippines (1); Miquelia caudata King, King 7621 (UC),
Malaysia (1); Polycephalium lobatum (Pierre) Pierre ex Engl., Bokdam 3062
(WAG), Congo (2); Pyrenacantha acuminata Engl., Wieringa 5017 (WAG),
Gabon (1); Pyrenacantha kaurabassana Baill., Reitsma 126 (WAG), Kenya (1);
Pyrenacantha kaurabassana Baill., Wilde 6359 (WAG), Ethiopia (1); Pyrenacantha
repanda Merr., Elmer 17359 (UC), Philippines (1); Pyrenacantha staudtii (Engl.)
Engl., Breteler 2968 (WAG), Cameroon (1); Pyrenacantha sylvestris S. Moore,
Breteler 11262 (WAG), Gabon (1).
Fossil fruits: *Chlamydocarya sp., s. n., Oligocene, Fayum Flora, Egypt;
*Palaeophytocrene ambigua Reid et Chandler, NHM v22646, early Eocene,
London Clay Flora, England; *Palaeophytocrene hancockii Scott emend.
Manchester, UM 29933 (and some UF and USNM specimens), middle
Eocene, Clarno Nut Beds flora, Oregon; Palaeophytocrene pseudopersica Scott
emend. Manchester, UF 8597, 8599, 8602, 8605-8610, middle Eocene, Nut
Beds Flora, Oregon; *Palaeophytocrene cf. pseudopersica Scott emend.
Manchester, UAPC-ALTA AW112, AW118, AW118, Eocene, Appian
Way, British Columbia; *Palaeophytocrene manchesteri Rankin, Stockey et
Beard, UAPC-ALTA AW301, Eocene, Appian Way, British Columbia;
*Palaeophytocrene vancouverensis Rankin, Stockey et Beard, UAPC-ALTA
AW363, Eocene, Appian Way, British Columbia; Phytocrene densipunctata
Stull, Moore et Manchester, UF 18927, middle Eocene, Cockfield Formation, Tennessee; Pyrenacantha occidentalis Manchester, UF 8617, middle
Eocene, Nut Beds flora, Oregon; *Pyrenacantha sp., s. n., Oligocene, Fayum
Flora, Egypt.