Allopleuron

{{Automatic taxobox

| fossil_range = Late Cretaceous–Oligocene
{{fossil range|94.3|28.4}}

| 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, 1831Gray, J.E. (1831), Synopsis Reptilium, Part I: [https://www.biodiversitylibrary.org/page/33482489 54] and [https://www.biodiversitylibrary.org/page/33482518 79]

| subdivision_ranks = Species

| subdivision_ref =

| subdivision = * †A. hofmanni {{small|(Gray, 1831)}}

†A. insulare {{small|(Cope, 1872)}}
†A. lipsiense {{small|Karl, 2007}}
†A. qazaqstanense {{small|Karl et al., 2012}}

}}

Allopleuron (meaning "other side") is a genus of extinct sea turtle, which measured {{convert|2|to|2.5|m|adj=on}} 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.{{cite journal |url=https://www.researchgate.net/publication/297915862 |last=Hirayama |first=Ren |date=2005 |title=SYSTEMATIC POSITION OF PROTOSPHARGIS VERONENSIS CAPELLINI, AN ENIGMATIC SEA TURTLE FROM THE LATE CRETACEOUS OF ITALY |journal=Journal of Vertebrate Paleontology |issue=25 |pages=70A}}

Fossil history

File:Allopleuron hoffmanni 13.jpg

Image:Allopleuron hoffmanni 87.JPG

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.{{cite journal |author1=Hans-Volker Karl |author2= Elke Gröning |author3=Carsten Brauckmann |year=2012 |title=New materials of the giant sea turtle Allopleuron (Testudines: Chelonioidea) from the marine Late Cretaceous of Central Europe and the Palaeogene of Kazakhstan |journal=Studia Palaeocheloniologica IV, Studia Geologica Salmanticensia |volume=9 |pages=153–173 |url=https://www.researchgate.net/publication/291056688}}{{Cite web|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=36326|title=Fossilworks: Allopleuron|website=fossilworks.org|access-date=17 December 2021}}

Life history

Allopleuron was believed to have used the Laurasian-Holarctic southern continental shelf as a breeding area.{{Cite journal|last=Universidad de Salamanca|first=Ediciones|date=2013-12-20|title=Índice|journal=Studia Historica. Historia Moderna|volume=35|page=1|doi=10.14201/11405|issn=0213-2079|doi-access=free}} The modern day location of the breeding ground is along the coast of Asia. Allopleuron is believed to have eaten jellyfish, seaweed, or carcasses;{{Cite web|url=http://oceansofkansas.com/Turtles.html|title=Marine Turtles|website=oceansofkansas.com|access-date=2019-05-05}} A. hofmanni δ¹³C values indicate a carnivorous diet.{{Cite journal |last1=van Baal |first1=Remy R. |last2=Janssen |first2=Renée |last3=van der Lubbe |first3=H.J.L. |last4=Schulp |first4=Anne S. |last5=Jagt |first5=John W.M. |last6=Vonhof |first6=Hubert B. |date=15 December 2013 |title=Oxygen and carbon stable isotope records of marine vertebrates from the type Maastrichtian, The Netherlands and northeast Belgium (Late Cretaceous) |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018213003945 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=392 |pages=71–78 |doi=10.1016/j.palaeo.2013.08.020 |bibcode=2013PPP...392...71V |access-date=1 December 2024 |via=Elsevier Science Direct}} 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):{{Cite journal|last1=Evers|first1=Serjoscha W.|last2=Barrett|first2=Paul M.|last3=Benson|first3=Roger B. J.|date=2019-05-01|title=Anatomy of Rhinochelys pulchriceps (Protostegidae) and marine adaptation during the early evolution of chelonioids|journal=PeerJ|volume=7|pages=e6811|doi=10.7717/peerj.6811|issn=2167-8359|pmc=6500378|pmid=31106054 |doi-access=free }}

{{Clade|style=font-size:85%;line-height:85%

|label1=Panchelonioidea

|1={{Clade

|1=†Toxochelys

|2={{Clade

|1=†Protostegidae

|label2=Chelonioidea

|2={{Clade

|1=†Corsochelys

|2=Dermochelyidae

|3={{Clade

|1=†Nichollsemys