Allopleuron

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title: "Allopleuron" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["prehistoric-turtles-of-asia", "late-cretaceous-turtles", "paleogene-turtles", "prehistoric-turtles-of-europe", "prehistoric-turtle-genera", "fossil-taxa-described-in-1831", "taxa-named-by-john-edward-gray", "cheloniidae"] description: "Extinct genus of turtles" topic_path: "general/prehistoric-turtles-of-asia" source: "https://en.wikipedia.org/wiki/Allopleuron" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct genus of turtles ::

| fossil_range = Late Cretaceous–Oligocene

| image = Allopleuron hoffmani.JPG | image_caption = Fossil specimen, Royal Belgian Institute of Natural Sciences | taxon = Allopleuron | authority = Baur, 1888 | type_species = Chelonia hofmanni | type_species_authority = Gray, 1831 | subdivision_ranks = Species | subdivision_ref = | subdivision = * †A. hofmanni (Gray, 1831)

• †A. insulare (Cope, 1872)
• †A. lipsiense Karl, 2007
• †A. qazaqstanense Karl et al., 2012

Allopleuron (meaning "other side") is a genus of extinct sea turtle, which measured 2 to long in life. The type species is Allopleuron hofmanni. It is a basal member of the clade Pancheloniidae, closely related to Protosphargis. Similar to Protosphargis, it was characterized by shell reduction.

Fossil history

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b3/Allopleuron_hoffmanni_13.jpg"] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/d/d9/Allopleuron_hoffmanni_87.JPG" caption="Top view"] ::

Allopleuron lived from the Late Cretaceous (Cenomanian age, 94.3 Ma) to the Oligocene (Rupelian age, 28.4 Ma), therefore surviving the Cretaceous-Paleogene extinction event. Fossils have been found from Germany, the Netherlands, Kazakhstan and the United States.

Life history

Allopleuron was believed to have used the Laurasian-Holarctic southern continental shelf as a breeding area. The modern day location of the breeding ground is along the coast of Asia. Allopleuron is believed to have eaten jellyfish, seaweed, or carcasses; A. hofmanni δ13C values indicate a carnivorous diet. It is believed that adult male Allopleuron lived off the coast of southeast Netherlands, and northeast Belgium due to the large amount of fossils in these areas. The area is believed to have been a sea grass meadow that was able to sustain the large population. The lack of remains from juvenile Allopleuron indicate that the young of the species lived elsewhere.

Phylogeny

Evers et al. (2019):

|label1=Panchelonioidea |1={{Clade |1=†Toxochelys |2={{Clade |1=†Protostegidae |label2=Chelonioidea |2={{Clade |1=†Corsochelys |2=Dermochelyidae |3={{Clade |1=†Nichollsemys |2={{Clade |1=†Allopleuron |2={{Clade |1=Cheloniidae |2={{Clade |1=†Argillochelys |2=†Procolpochelys |3={{Clade |1=†Eochelone |2=†Puppigerus }} |4={{Clade |1=†Ctenochelys |2=†Peritresius |3=†Cabindachelys

References

References

1. Gray, J.E. (1831), ''Synopsis Reptilium'', Part I: [https://www.biodiversitylibrary.org/page/33482489 54] and [https://www.biodiversitylibrary.org/page/33482518 79]
2. Hirayama, Ren. (2005). "SYSTEMATIC POSITION OF PROTOSPHARGIS VERONENSIS CAPELLINI, AN ENIGMATIC SEA TURTLE FROM THE LATE CRETACEOUS OF ITALY". Journal of Vertebrate Paleontology.
3. (2012). "New materials of the giant sea turtle ''Allopleuron'' (Testudines: Chelonioidea) from the marine Late Cretaceous of Central Europe and the Palaeogene of Kazakhstan". Studia Palaeocheloniologica IV, Studia Geologica Salmanticensia.
4. "Fossilworks: Allopleuron".
5. Universidad de Salamanca, Ediciones. (2013-12-20). "Índice". Studia Historica. Historia Moderna.
6. "Marine Turtles".
7. (15 December 2013). "Oxygen and carbon stable isotope records of marine vertebrates from the type Maastrichtian, The Netherlands and northeast Belgium (Late Cretaceous)". [[Palaeogeography, Palaeoclimatology, Palaeoecology]].
8. (2019-05-01). "Anatomy of Rhinochelys pulchriceps (Protostegidae) and marine adaptation during the early evolution of chelonioids". PeerJ.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::