Paleobiota of the Green River Formation explained

The Green River Formation is a famous Konservat-Lagerstätte located in the Intermountain West of the United States, in the states of Colorado, Utah, and Wyoming. It comprises sediments deposited during the Early Eocene in a series of large freshwater lakes: Lake Gosiute, Lake Uinta, and Fossil Lake (the last containing Fossil Butte National Monument). It preserves a high diversity of freshwater fish, birds, reptiles, and mammals.

Cartilaginous fish

Genus	Species	Member	Abundance	Notes	Image
Asterotrygon	A. maloneyi	Fossil Lake		A stingray of uncertain affinities.^[1]
Heliobatis	H. radians			A stingray of uncertain affinities.

Bony fish

Primarily based on Grande (2001), with changes where necessary:

Lepisosteiformes

Genus	Species	Member	Abundance	Notes	Image
Atractosteus	A. atrox	Fossil Lake		A gar related to the alligator gar. A. atrox is the largest of the Green River gar species.
	A. simplex	Fossil Lake, possibly Lake Gosiute
Cuneatus	C. cuneatus	Lake Gosiute, Lake Uinta, possibly Fossil Lake		A gar.
	C. wileyi	Lake Uinta
Lepisosteus	L. bemisi	Fossil Lake		A gar.^[2]
Masillosteus	M. janeae	Fossil Lake		A gar.

Amiiformes

Genus	Species	Member	Abundance	Notes	Image
Amia	A. pattersoni	Fossil Lake, Lake Gosiute		An amiid related to modern bowfins.
Cyclurus	C. gurleyi	Fossil Lake	Only 8 specimens known	An amiid.

Osteoglossiformes

Genus	Species	Member	Abundance	Notes	Image
Phareodus	P. encaustus	Fossil Lake, Lake Gosiute		A bonytongue.
	P. testis	Fossil Lake

Clupeiformes

Genus	Species	Member	Abundance	Notes	Image
Gosiutichthys	G. parvus	Lake Gosiute		A clupeiform.
Knightia	K. alta	Fossil Lake, Lake Gosiute & Lake Uinta		A clupeid.^[3] The most commonly found articulated vertebrate fossil in the world.^[4]
	K. eocaena		The most common fish of the formation.

Siluriformes

Genus	Species	Member	Abundance	Notes	Image
Astephus	A. antiquus	Lake Gosiute, Lake Uinta, Fossil Lake	Only one specimen known from Fossil Lake.	An ictalurid catfish.
Hypsidoris	H. farsonensis	Lake Gosiute		A hypsidorid catfish.

Percopsiformes

Genus	Species	Member	Abundance	Notes	Image
Amphiplaga	A. brachyptera	Fossil Lake		A relative of trout-perch.
Erismatopterus	E. levatus	Lake Gosiute, Lake Uinta		A relative of trout-perch.

Moroniformes

Genus	Species	Member	Abundance	Notes	Image
Cockerellites	C. liops	Fossil Lake		A temperate bass.
Hypsiprisca	H. hypsacantha	Fossil Lake		A temperate bass.
	H. sp.
Priscacara	P. serrata	Fossil Lake, Lake Uinta		A temperate bass.
	P. sp. a	Fossil Lake
	P. sp. b.

Incertae sedis

Genus	Species	Member	Abundance	Notes	Image
Asineops	A. squamifrons	Fossil Lake, Lake Gosiute, Lake Uinta		An acanthomorph of uncertain affinities, possibly a percopsiform, polymixiiform, or perciform.
	A. sp.	Fossil Lake

Amphibians

Salamanders

Reptiles

Squamates

Genus	Species	Member	Abundance	Notes	Image
Afairiguana	A. avius	Fossil Lake		A stem-anole.^[6]
Bahndwivici	B. ammoskius			A relative of the Chinese crocodile lizard.
Boavus	B. idelmani			A boa.
Dunnophis	D. sp.			Possibly a dwarf boa.^[7]
Saniwa	S. ensidens			A stem-monitor lizard.
Shinisauridae indet.		Lake Uinta		A relative of the Chinese crocodile lizard, unusually preserved with a mineralized body without a skeleton.^[8]

Crocodilians

Genus	Species	Member	Abundance	Notes	Image
Borealosuchus	B. wilsoni	Fossil Lake		A eusuchian of uncertain affinities.
Tsoabichi	T. greenriverensis			A caiman.^[9]

Turtles

Genus	Species	Member	Abundance	Notes	Image
Axestemys	A. sp.	Fossil Lake		A softshell turtle.
Baptemys	B. wyomingensis			A dermatemydid.
Chisternon	C. undatum			A baenid.
Echmatemys	E. wyomingensis			A geoemydid.^[10]
Oliveremys	O. uintaensis			A softshell turtle.
Plastomenus	P. thomasii			A softshell turtle.

Birds

Lithornithiformes

Genus	Species	Member	Abundance	Notes	Image
Calciavis	C. grandei	Fossil Lake		A lithornithid.^[11]
Pseudocrypturus	P. cercanaxius			A lithornithid.

Anseriformes

Genus	Species	Member	Abundance	Notes	Image
Paakniwatavis	P. grandei	Fossil Lake		An anseriform of uncertain affinities.
Presbyornis	P. pervetus			A presbyornithid anseriform.

Leptosomiformes

Genus	Species	Member	Abundance	Notes	Image
Plesiocathartes	P. major	Fossil Lake		A stem-cuckoo roller.^[12]
	P. wyomingensis

Coraciiformes

Genus	Species	Member	Abundance	Notes	Image
Paracoracias	P. occidentalis			A coraciiform.^[13]
Primobucco	P. mcgrewi	Fossil Lake		A primobucconid coraciiform.

Piciformes

Genus	Species	Member	Abundance	Notes	Image
Neanis	N. schucherti	Fossil Lake		A possible piciform of uncertain affinities.
Pristineanis	P. kistneri			A possible piciform of uncertain affinities.^[14]

Strisores

Genus	Species	Member	Abundance	Notes	Image
Eocypselus	E. rowei	Fossil Lake		A eocypselid apodiform.^[15]
Fluvioviridavis	F. platyrhamphus			A basal strisore, possibly a stem-frogmouth.^[16] ^[17]
Prefica	P. nivea			A stem-oilbird.^[18]

Suliformes

Genus	Species	Member	Abundance	Notes	Image
Limnofregata	L. azygosternon	Fossil Lake		An early frigatebird.
	L. hasegawai

Eufalconimorphae

Genus	Species	Member	Abundance	Notes	Image
Avolatavis	A. tenens	Fossil Lake		A quercypsittid.
Cyrilavis	C. colburnorum			A halcyornithid.
	C. olsoni
Eofringillirostrum	E. boudreauxi			A psittacopedid.^[21]
Eozygodactylus	E. americanus			A zygodactylid.^[22]
Tynskya	T. eocaena			A messelasturid.
Zygodactylus	Z. grandei			A zygodactylid.^[23]

Neoaves incertae sedis

Two other genera, Eoeurypyga (a stem-sunbittern) and Wyomingcypselus (an early apodiform) are mentioned only in a 2002 dissertation^[25], and are presently nomina nuda.

Mammals

Chiroptera

Genus	Species	Member	Abundance	Notes	Image
Icaronycteris	I. gunnelli	Fossil Lake	2 skeletons.^[26]	An icaronycterid bat.
	I. index
Onychonycteris	O. finneyi			An onychonycterid bat.

Perissodactyla

Genus	Species	Member	Abundance	Notes	Image
Lambdotherium	L. popoagicum	Fossil Lake		A small-sized basal brontothere.
Protorohippus	P. venticolus		2 skeletons.	An equid.

Cimolesta

Notes and References

1. De Carvalho . Marcelo R. . Maisey . John G. . Grande . Lance . June 2004 . Freshwater Stingrays of the Green River Formation of Wyoming (Early Eocene), With the Description of a New Genus and Species and an Analysis of Its Phylogenetic Relationships (Chondrichthyes: Myliobatiformes) . Bulletin of the American Museum of Natural History . en . 284 . 1–136 . 10.1206/0003-0090(2004)284<0001:FSOTGR>2.0.CO;2 . 0003-0090.
2. Schwartz . Frank J. . 2011-10-01 . An Emperical Synthetic Pattern Study of Gars (Lepisosteiformes) and Closely Related Species, Based Mostly on Skeletal Anatomy the Resurrection of Holostei . Journal of North Carolina Academy of Science . en . 127 . 3 . 219 . 10.7572/2167-5880-127.3.219 . 2167-5880.
3. Near . Thomas J. . Thacker . Christine E. . 2024-04-18 . Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii) . Bulletin of the Peabody Museum of Natural History . 65 . 1 . 10.3374/014.065.0101 . 0079-032X.
4. Web site: Fossil Fish - Fossil Butte National Monument (U.S. National Park Service) . 2024-08-17 . www.nps.gov . en.
5. Henrici . Amy C. . Báez . Ana M. . Grande . Lance . 2013 . Aerugoamnis paulus, New Genus and New Species (Anura: Anomocoela): First Reported Anuran from the Early Eocene (Wasatchian) Fossil Butte Member of the Green River Formation, Wyoming . Annals of Carnegie Museum . en . 81 . 4 . 295–309 . 10.2992/007.081.0402 . 0097-4463.
6. Scarpetta . Simon G. . 2024 . A Palaeogene stem crotaphytid (Aciprion formosum) and the phylogenetic affinities of early fossil pleurodontan iguanians . Royal Society Open Science . en . 11 . 1 . 10.1098/rsos.221139 . 2054-5703 . 10776235 . 38204790. 2024RSOS...1121139S .
7. Web site: PBDB Taxon . 2024-08-17 . paleobiodb.org.
8. Carpenter . Kenneth . 2018-10-18 . Soft-bodied fossil of a lizard from the Parachute Creek Member, Green River Formation (Eocene), Utah . Geology of the Intermountain West . en . 5 . 263–269 . 10.31711/giw.v5.pp263-269 . 2380-7601.
9. Brochu . Christopher A. . 2010-07-14 . A new alligatorid from the lower Eocene Green River Formation of Wyoming and the origin of caimans . Journal of Vertebrate Paleontology . en . 30 . 4 . 1109–1126 . 10.1080/02724634.2010.483569 . 2010JVPal..30.1109B . 0272-4634.
10. Vlachos . Evangelos . 2020-07-17 . The turtles from 'Gilmore's slab': evolution and diversity of the extinct turtle Echmatemys (Testudines: Testudinoidea: Geoemydidae) from the central United States . Journal of Systematic Palaeontology . en . 18 . 14 . 1193–1216 . 10.1080/14772019.2020.1754938 . 2020JSPal..18.1193V . 1477-2019.
11. Musser . Grace . Clarke . Julia A. . 2024-07-30 . A new Paleogene fossil and a new dataset for waterfowl (Aves: Anseriformes) clarify phylogeny, ecological evolution, and avian evolution at the K-Pg Boundary . PLOS ONE . en . 19 . 7 . e0278737 . 10.1371/journal.pone.0278737 . free . 1932-6203 . 11288464 . 39078833.
12. Weidig . Ilka . 2006 . The first New World occurrence of the Eocene birdPlesiocathartes (Aves: ?Leptosomidae) . Paläontologische Zeitschrift . en . 80 . 3 . 230–237 . 10.1007/BF02988439 . 2006PalZ...80..230W.
13. Clarke . Julia A. . Ksepka . Daniel T. . Smith . N. Adam . Norell . Mark A. . 2009-10-26 . Combined phylogenetic analysis of a new North American fossil species confirms widespread Eocene distribution for stem rollers (Aves, Coracii): NEW SPECIES FROM THE EOCENE GREEN RIVER FORMATION . Zoological Journal of the Linnean Society . en . 157 . 3 . 586–611 . 10.1111/j.1096-3642.2009.00550.x.
14. Mayr . Gerald . Kitchener . Andrew C. . 2024-06-01 . The Picocoraciades (hoopoes, rollers, woodpeckers, and allies) from the early Eocene London Clay of Walton-on-the-Naze . PalZ . en . 98 . 2 . 291–312 . 10.1007/s12542-024-00687-9 . 1867-6812.
15. Ksepka . Daniel T. . Clarke . Julia A. . Nesbitt . Sterling J. . Kulp . Felicia B. . Grande . Lance . 2013-06-22 . Fossil evidence of wing shape in a stem relative of swifts and hummingbirds (Aves, Pan-Apodiformes) . Proceedings of the Royal Society B: Biological Sciences . 280 . 1761 . 20130580 . 10.1098/rspb.2013.0580 . 0962-8452 . 3652446 . 23760643.
16. Nesbitt . Sterling J. . Ksepka . Daniel T. . Clarke . Julia A. . 2011-11-30 . Podargiform Affinities of the Enigmatic Fluvioviridavis platyrhamphus and the Early Diversification of Strisores ("Caprimulgiformes" + Apodiformes) . PLOS ONE . en . 6 . 11 . e26350 . 10.1371/journal.pone.0026350 . free . 1932-6203 . 3227577 . 22140427. 2011PLoSO...626350N .
17. Mayr . Gerald . Kitchener . Andrew C. . 2024-06-07 . The non-apodiform Strisores (potoos, nightjars and allied birds) from the early Eocene London Clay of Walton-on-the-Naze . Palaeobiodiversity and Palaeoenvironments . en . 10.1007/s12549-024-00610-9 . 2024PdPe..tmp...21M . 1867-1608.
18. Mayr . Gerald . 2005 . The Palaeogene Old World potoo Paraprefica Mayr, 1999 (Aves, Nyctibiidae): Its osteology and affinities to the New World Preficinae Olson, 1987 . Journal of Systematic Palaeontology . en . 3 . 4 . 359–370 . 10.1017/S1477201905001653 . 2005JSPal...3..359M . 1477-2019.
19. Field . Daniel J. . Hsiang . Allison Y. . 2018-06-25 . A North American stem turaco, and the complex biogeographic history of modern birds . BMC Evolutionary Biology . en . 18 . 1 . 102 . 10.1186/s12862-018-1212-3 . free . 1471-2148 . 6016133 . 29936914. 2018BMCEE..18..102F .
20. Smith . Nathan D. . Grande . Lance . Clarke . Julia A. . 2013 . A new species of Threskiornithidae-like bird (Aves, Ciconiiformes) from the Green River Formation (Eocene) of Wyoming . Journal of Vertebrate Paleontology . en . 33 . 2 . 363–381 . 10.1080/02724634.2012.722898 . 2013JVPal..33..363S . 0272-4634.
21. Ksepka . Daniel T. . Grande . Lance . Mayr . Gerald . 2019 . Oldest Finch-Beaked Birds Reveal Parallel Ecological Radiations in the Earliest Evolution of Passerines . Current Biology . 29 . 4 . 657–663.e1 . 10.1016/j.cub.2018.12.040 . 2019CBio...29E.657K . 0960-9822.
22. Weidig . Ilka . 2010-05-26 . New birds from the Lower Eocene Green River Formation, North America. In Proceedings of the VII International Meeting of the Society of Avian Paleontology and Evolution, ed. W.E. Boles and T.H. Worthy . Records of the Australian Museum . en . 62 . 1 . 29–44 . 10.3853/j.0067-1975.62.2010.1544 . 0067-1975.
23. Smith . N. Adam . DeBee . Aj M. . Clarke . Julia A. . 2018-06-25 . Systematics and phylogeny of the Zygodactylidae (Aves, Neognathae) with description of a new species from the early Eocene of Wyoming, USA . PeerJ . en . 6 . e4950 . 10.7717/peerj.4950 . free . 29967716 . 6022727 . 2167-8359.
24. Musser . Grace . Clarke . Julia A. . 2020-10-26 . An Exceptionally Preserved Specimen From the Green River Formation Elucidates Complex Phenotypic Evolution in Gruiformes and Charadriiformes . Frontiers in Ecology and Evolution . English . 8 . 10.3389/fevo.2020.559929 . free . 2296-701X.
25. Fossil birds from the lower eocene Green River formation (USA) . Universitätsbibliothek Johann Christian Senckenberg . 2003 . Ilka . Weidig.
26. Rietbergen . Tim B. . Ostende . Lars W. van den Hoek . Aase . Arvid . Jones . Matthew F. . Medeiros . Edward D. . Simmons . Nancy B. . 2023-04-12 . The oldest known bat skeletons and their implications for Eocene chiropteran diversification . PLOS ONE . en . 18 . 4 . e0283505 . 10.1371/journal.pone.0283505 . free . 1932-6203 . 10096270 . 37043445. 2023PLoSO..1883505R .