A comparison of plant-insect associations in the middle Eocene Green River Formation and the Upper Eocene Florissant Formation and their climatic implications

2008 ◽  
Author(s):  
Dena M. Smith
Keyword(s):  
Middle Eocene ◽  
Green River Formation ◽  
Upper Eocene ◽  
Green River ◽  
Florissant Formation

The second genus of the extinct dragonfly family Urolibellulidae from the Eocene Green River Formation (Odonata, Anisoptera: Cavilabiata)

2020 ◽  
Vol 3 (1) ◽  
pp. 050-053 ◽  
Author(s):  
ANDRÉ NEL
Keyword(s):  
Middle Eocene ◽  
Green River Formation ◽  
Green River

If the oldest record of the anisopteran ‘libelluloid’ group Anauriculida Bechly, 1996 goes to the Cretaceous (Fleck et al., 1999; Kohli et al., 2016), its extant families are scarce or even absent before the Eocene. Nevertheless, the Anauriculida were already rather diverse during Eocene with a Libellulidae in the earliest Eocene (Fleck et al., 2000), and the extinct monotypic family Urolibellulidae in the middle Eocene Green River Formation (Zeiri et al., 2015). Crown Libellulidae become more and more frequent and diverse during Oligocene, and even dominate the dragonfly fauna in some outcrops (Céreste, Rott, Aix-en-Provence, Bes-Konak) (Nel & Paicheler, 1993). Thus any discovery in the Paleocene–Eocene of a new fossil related to these families is welcome. Here we describe a complete hindwing of this kind from the Green River Formation in Colorado.

scholarly journals Bonanzacarpum sprungerorum Sp. Nov. – A Bizarre Fruit from the Eocene Green River Formation in Utah, USA

2019 ◽  
Vol 75 (2) ◽  
pp. 281-288
Author(s):  
Steven R. Manchester ◽  
Terry A. Lott
Keyword(s):  
Middle Eocene ◽  
Three Dimensional ◽  
Systematic Position ◽  
Lateral View ◽  
Green River Formation ◽  
Fossil Plant ◽  
Green River ◽  
Fruit Type ◽  
Reflected Light ◽  
Plant Remains

Abstract Shales of the early middle Eocene Parachute Creek Member of the Green River Formation in Utah, western USA, have yielded a large number of fossil plant remains with abundant Platanaceae, Salicaceae, and Ulmaceae, but many of the constituents of this flora remain indeterminate. Here we present a new fruit type based on distinctive sedimentary molds investigated by reflected light and μCT scanning. The structures are oblate woody fruits, about 18–26 mm wide but only 2–4 mm high, but partially flattened by compression within the sediment. In transverse view they are rounded-polygonal, with 5–6 sides. In lateral view the locule is dome-shaped with 7 to 11 obpyriform grooves radiating from the center of the basal wall. Three-dimensional imaging and both physical and digital sections indicate that the fruits were circumscissile capsules. Although analogous fruits occur in the Lecythidaceae A.Rich., Bonanzacarpum sprungerorum sp. nov. fruits are much smaller and lack the prominent woody pedicel and corresponding basal scar that characterizes that family. Hence, the systematic position of B. sprungerorum remains uncertain.

scholarly journals First record of the subfamily Sagrinae (Coleoptera: Chrysomelidae) from the Eocene of North America

Fossil Record ◽  
2021 ◽  
Vol 24 (1) ◽  
pp. 135-139
Author(s):  
Andrei A. Legalov
Keyword(s):  
North America ◽  
Type Species ◽  
New Genus ◽  
Middle Eocene ◽  
First Record ◽  
Green River Formation ◽  
Green River ◽  
The Family

Abstract. A new genus, Palaeatalasis gen. nov. (type species P. monrosi sp. nov.), from the tribe Megamerini (Chrysomelidae: Sagrinae) from the early-middle Eocene Green River Formation is described and illustrated. The new genus is similar to the Recent Atalasis Lacordaire, 1845 but differs from it in the subparallel sides of the pronotum, metafemora without teeth, and non-emarginate eyes. It differs from the Eocene Eosagra Haupt, 1950 in the large, convex, non-emarginate eyes, wide elytra, and transverse pronotum. The new genus is distinguished from the Paleocene Gallopsis Legalov, Kirejtshuk et Nel, 2019 in the wide forehead and convex eyes. It is the first record of the Sagrinae from North America and the fourth known species of the family Chrysomelidae from the Green River.

Antiquity and Evolution of Prosternal Horns in Baridine Weevils (Coleoptera: Curculionidae)

2010 ◽  
Vol 84 (5) ◽  
pp. 918-926 ◽  
Author(s):  
Steven R. Davis ◽  
Michael S. Engel
Keyword(s):  
Middle Eocene ◽  
Green River Formation ◽  
Unique Form ◽  
Male Aggression ◽  
Green River ◽  
Minimum Age ◽  
Horned Beetles

Among weevils of the subfamily Baridinae (548 extant genera and ca. 9,000 species), unique prosternal horns and associated sheaths have evolved independently multiple times. These structures are utilized in a unique form of male-male aggression in which males push, rather than overturn as in most other horned beetles, their competitor. Herein we report the first fossils of male Baridinae exhibiting such prosternal horns. Two males recovered from the middle Eocene Green River Formation in northwestern Colorado serve to provide a minimum age (at ca. 47 million years old) for both the origin of horns and its associated form of male-male combat in Baridinae.

scholarly journals Past ecosystems drive the evolution of the early diverged Symphyta (Hymenoptera: Xyelidae) since the earliest Eocene

Fossil Record ◽  
2021 ◽  
Vol 24 (2) ◽  
pp. 379-393
Author(s):  
Corentin Jouault ◽  
Arvid Aase ◽  
André Nel
Keyword(s):  
New Records ◽  
Wing Venation ◽  
Upper Eocene ◽  
Green River ◽  
Lower Eocene ◽  
The Past ◽  
Host Trees ◽  
The Family ◽  
Florissant Formation ◽  
Lake Deposits

Abstract. Paleoxyela nearctica gen. et sp. nov., is described from the upper Eocene of Florissant Formation in Colorado. We placed Paleoxyela gen. nov. in the subfamily Macroxyelinae and the tribe Macroxyelini based on the numerous wing venation characters visible on the specimen. Proxyelia pankowskii gen. et sp. nov. is described from the lower Eocene Fossil Lake deposits of the Green River Formation in Wyoming. We placed Proxyelia gen. nov. in the subfamily Macroxyelinae and the tribe Xyeleciini based on the numerous wing venation characters visible on the specimen. These new records of the family Xyelidae are of particular importance to better understand the past diversity of the clade and propose hypotheses about their diversification. Extant Xyelidae inhabit temperate Northern Hemisphere forests, and most of their larvae feed on conifers, which may explain why they are relatively poorly diversified compared to the other symphytan families. We suggest that the global decline in conifers and the reduced diversity of extant host trees partly explain the diversity of extant Xyelidae. We correlate the biome repartition during the Eocene to that of the extant xyelid.

New records of insect families from the freshwater Middle Eocene of British Columbia

1977 ◽  
Vol 14 (5) ◽  
pp. 1139-1155 ◽  
Author(s):  
Mark V. H. Wilson
Keyword(s):  
British Columbia ◽  
New Records ◽  
Middle Eocene ◽  
Green River Formation ◽  
Green River ◽  
First Time

New collections of Middle Eocene insects from seven localities in British Columbia include representatives of 17 families, in seven orders, bringing the total number of families recorded for the fauna to 31, distributed among 10 orders. The Mastotermitidae, Pentatomidae, Trichoptera, Sciaridae, Mycetophilidae, Syrphidae, and Vespidae are recorded from the fauna for the first time. The single specimens each of Syrphidae and Vespidae are among the oldest known of their respective taxa.Only one family, the Mastotermitidae, is not also known from either the Green River Formation or the Florissant Shales. The composition of fauna within British Columbia suggests age or environmental differences between the Horsefly and Princeton area localities, with the Driftwood Creek locality intermediate.

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