Eosphargis

Eosphargis; Temporal range: Late Paleocene to Early Eocene, 59–51.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N
	Eosphargis breineri skull cast at the University of Copenhagen Geological Museum
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Family:	Dermochelyidae
Genus:	†Eosphargis; Lydekker, 1889
Species
	†E. breineri Nielsen, 1959; †E. gigas (Owen, 1880); †E. insularis (Cope, 1872);
Synonyms
	†Anglocetus Tarlo, 1964; †Lembonax Cope, 1872;

Eosphargis (from Greek eos, meaning "dawn", and sphargis, the Greek word for the leatherback turtle) is an extinct genus of sea turtles from the late Paleocene and early Eocene of western Europe and eastern North America.^[1] It is a member of the family Dermochelyidae, which also includes the modern leatherback sea turtle (Dermochelys coriacea), of which it is the earliest known definitive member.^[2]

Taxonomy

The genus Eosphargis was first described by British paleontologist Richard Lydekker in 1889. It contains three known species:^[1]^[2]

The following species are known:

†E. breineri Nielsen, 1959 - Early Eocene of Denmark (Fur Formation)
†E. gigas (Owen, 1880) - Early Eocene of England (London Clay), potentially Maryland, US (Nanjemoy Formation)^[3]
†E. insularis (Cope, 1872) - Late Paleocene of New Jersey, US (Vincentown Formation) and Virginia, US (Aquia Formation)^[3]

It is possible that E. insularis is conspecific with one of the two other known species, as it is known from only fragmentary material.^[3] It was excluded from a 2025 taxonomic review for this reason.^[2] E. breineri is known from the Fur Formation lagerstatte of Denmark, and is thus the species with the best-preserved remains.^[4]

In 1964, an alleged record of a scapula from an early archaeocete whale from the London Clay was described as †Anglocetus beatsoni Tarlo, 1964. This would have been one of the earliest known whales, and one of the only known from the Eocene of Europe. However, a later analysis found this bone to likely belong to an individual of E. gigas.^[5]

External links

Eosphargis at the Paleobiology Database

References

^ ^a ^b "PBDB". paleobiodb.org. Archived from the original on 2024-04-01. Retrieved 2025-10-11.
^ ^a ^b ^c Gentry, Andrew D.; Burns, Michael E.; Ebersole, Jun A.; Gregson, Kimberly A.; Martinez, Emma C.; Parham, James F. (2025-09-12). "A new leatherback marine turtle from the lower Oligocene of North America and a phylogenetic nomenclature for Dermochelyidae". Palaeodiversity. 18 (1). doi:10.18476/pale.v18.a6. ISSN 1867-6294.
^ ^a ^b ^c Weems, Robert E. (2014-05-27). "Paleogene chelonians from Maryland and Virginia". PaleoBios. 31 (1). doi:10.5070/P9311022744. ISSN 0031-0298.
^ NIELSEN, E. (1964). "On the post-cranial skeleton of Eosphargis breineri Nielsen". Bulletin of the Geological Society of Denmark. 15: 281–328.
^ HALSTEAD, L. B (1984). "The first whale (Anglocetus beatsoni) is a turtle". The first whale (Anglocetus beatsoni) is a turtle. 6 (1): 1–4. ISSN 0308-9649.

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[:0-1] "PBDB". paleobiodb.org. Archived from the original on 2024-04-01. Retrieved 2025-10-11.

[:1-2] Gentry, Andrew D.; Burns, Michael E.; Ebersole, Jun A.; Gregson, Kimberly A.; Martinez, Emma C.; Parham, James F. (2025-09-12). "A new leatherback marine turtle from the lower Oligocene of North America and a phylogenetic nomenclature for Dermochelyidae". Palaeodiversity. 18 (1). doi:10.18476/pale.v18.a6. ISSN 1867-6294.

[:2-3] Weems, Robert E. (2014-05-27). "Paleogene chelonians from Maryland and Virginia". PaleoBios. 31 (1). doi:10.5070/P9311022744. ISSN 0031-0298.

[4] NIELSEN, E. (1964). "On the post-cranial skeleton of Eosphargis breineri Nielsen". Bulletin of the Geological Society of Denmark. 15: 281–328.

[5] HALSTEAD, L. B (1984). "The first whale (Anglocetus beatsoni) is a turtle". The first whale (Anglocetus beatsoni) is a turtle. 6 (1): 1–4. ISSN 0308-9649.

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