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Thalassochelydia

Osteichthyes

Discussion

The name Thalassochelydia is here referred to the clade that includes all turtles more closely related to Eurysternum wagleri Meyer, 1839c, Plesiochelys etalloni (Pictet and Humbert, 1857), and Thalassemys hugii Rütimeyer, 1873a, than to Pelomedusa subrufa (Bonnaterre, 1789), Testudo graeca Linnaeus, 1758, or Protostega gigas (Cope, 1871). Eucryptodiran turtles from the Late Jurassic of Europe were traditionally classified in several families, in particular Eurysternidae, Plesiochelyidae, and Thalassemydidae, but we are unaware of any higher level name having been pro- posed to unite all into a group. We here recognize that some information is available that hints at the monophyly of these turtles and we therefore here propose a new name for that group, Thalassochelydia, in allusion to their predominantly marine habitat preferences. Increased taxon sampling and the development of new cranial characters recently allowed this group to be supported in a phylogenetic context (Anquetin et al. 2015). In order to avoid potential conflict with the phylogenetic definition of Protostegidae Cope, 1872, as recently proposed by Cadena and Parham (2015), our definition of Thalassochelydia specifically excludes the species Protostega gigas (Cope, 1871).

Synonyms
Synonymy list
YearName and author
1856Acichelys approximata Wagner p. 23
1861Euryaspis radians Wagner p. 89 figs. plate 2
1861Euryaspis approximata Wagner p. 92
1880Tropidemys morinica Sauvage pp. 536-537 figs. Pl. XX:1-3
1924Plesiochelys oblonga Oertel
1924Plesiochelys pumilio Oertel
1924Thalassemys heusseri Oertel
2017Thalassochelydia Anquetin et al.
2020Thalassochelydia Anquetin and Püntener
2020Thalassochelydia Joyce and Mäuser
2021Thalassochelydia Pérez-Garcia and Ortega

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
classOsteichthyes
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
RankNameAuthor
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
Sauropsida
classReptilia
subclassEureptilia()
Romeriida
Diapsida()
Archosauromorpha(Huene 1946)
ArchelosauriaCrawford 2015
Pantestudines
Testudinata(Oppel 1811)
Thalassochelydia
Thalassochelydia

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Unr. †Thalassochelydia Anquetin et al. 2017
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G. †Achelonia von Meyer 1860
+
Achelonia formosa von Meyer 1860
Fm. †Eurysternidae Dollo 1886
+
G. †Chelonides Maack 1869
+
Chelonides wittei Maack 1869
G. †Hydropelta Meyer 1850
+
Hydropelta meyeri Tholliere 1851
G. †Idiochelys Meyer 1839
+
Idiochelys fitzingeri Meyer 1839
+
Invalid names: Chelonemys ovata Jourdan 1862 [synonym], Chelonemys plana Jourdan 1862 [synonym], Idiochelys wagneri Meyer 1846 [synonym]
Idiochelys wagneri Meyer 1846
G. †Palaeomedusa Meyer 1860
+
Palaeomedusa testa von Meyer 1860
+
Invalid names: Eurysternum crassipes Wagner 1861 [objective synonym]
G. †Parachelys Meyer 1864
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Parachelys eichstaettensis von Meyer 1864
Invalid names: Plesiochelys minima Oertel 1915 [nomen dubium]
G. †Eurysternum Meyer 1839
+
Eurysternum neuquinum Fernandez and de la Fuente 1988
Eurysternum wagleri Meyer 1839
G. †Hylaeochelys Lydekker 1889
+
Hylaeochelys belli Mantell 1844
+
Invalid names: Archaeochelys valdensis Lydekker 1889 [synonym], Hylaeochelys sollasi Nopcsa 1928 [synonym], Platemys dixoni Owen 1853 [synonym], Platemys mantelli Owen 1841 [synonym]
Hylaeochelys kappa Pérez-García and Ortega 2014
+
Invalid names: Pleurosternon koeneni Grabbe 1884 [synonym]
Invalid names: Archaeochelys Lydekker 1889 [synonym]
G. †Jurassichelon Pérez-García 2015
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Jurassichelon moseri Bräm 1965
Jurassichelon oleronensis Pérez-García 2015
G. †Neusticemys Fernandez and de la Fuente 1993
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Neusticemys neuquina Fernandez and de la Fuente 1988
Fm. †Plesiochelyidae Rütimeyer 1873
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G. †Craspedochelys Rütimeyer 1873
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Craspedochelys jaccardi Pictet 1860
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Invalid names: Plesiochelys choffati Sauvage 1898 [synonym]
Craspedochelys passmorei Andrews 1921
Craspedochelys picteti Rütimeyer 1873
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Invalid names: Craspedochelys crassa Rütimeyer 1873 [synonym]
Craspedochelys renzi Cadena et al. 2025
Invalid names: Emys dollfusii Lennier 1870 [nomen dubium]
G. †Globochelus de Lapparent de Broin et al. 2021
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Globochelus lennieri de Lapparent de Broin et al. 2021
G. †Plesiochelys Rütimeyer 1873
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Plesiochelys bigleri Puntener et al. 2017
Plesiochelys etalloni Pictet and Humbert 1857
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Invalid names: Plesiochelys langii Rütimeyer 1873 [synonym], Plesiochelys sanctaeverenae Rütimeyer 1873 [synonym], Plesiochelys solodurensis Rütimeyer 1873 [synonym], Stylemys hannoverana Maack 1869 [synonym], Stylemys lindenensis Maack 1869 [synonym]
Plesiochelys normandicus Bergounioux 1937
Invalid names: Clemmys grayi Fitzinger 1835 [nomen oblitum], Emys hugi Gray 1831 [nomen oblitum], Emys hugii Gray 1831 [nomen oblitum], Emys jurensis Keferstein 1834 [nomen oblitum], Emys trionychoides Gray 1831 [nomen oblitum], Plesiochelys minor Portis 1878 [nomen dubium], Stegochelys Lydekker 1889 [synonym]
G. †Portlandemys Gaffney 1975
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Portlandemys gracilis Anquetin et al. 2015
Portlandemys mcdowelli Gaffney 1975
G. †Tholemys Andrews 1921
G. †Yanduchelys Peng et al. 2005
+
Yanduchelys delicatus Peng et al. 2005
Invalid names: Emys dutertrei Sauvage 1872 [nomen dubium], Hispaniachelys Slater et al. 2011 [nomen dubium], Hispaniachelys prebetica Slater et al. 2011 [nomen dubium], Stylemys lindenensis Maack 1869 [nomen dubium]
G. †Solnhofia Gaffney 1975
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Solnhofia brachyrhyncha Anquetin and Püntener 2020
Solnhofia parsonsi Gaffney 1975
G. †Thalassemys Rütimeyer 1859
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Thalassemys bruntrutana Puntener et al. 2015
Thalassemys carva Nessov 1984
Thalassemys hugii Rütimeyer 1873
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Invalid names: Eurysternum ignoratum Bräm 1965 [synonym], Thalassemys gresslyi Rütimeyer 1873 [synonym]
Invalid names: Parathalassemys Nessov and Krassevskaya 1984 [synonym]
G. †Tropidemys Rütimeyer 1873
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Pelobatochelys blakii Seeley 1875
Tropidemys langii Rütimeyer 1873
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Invalid names: Craspedochelys plana Rütimeyer 1873 [synonym], Tropidemys expansa Rütimeyer 1873 [synonym], Tropidemys gibba Rütimeyer 1873 [synonym]
Tropidemys seebachi Portis 1878
Invalid names: Chelonia valanginiensis Pictet and Campiche 1862 [nomen dubium], Chelonides robusta Portis 1878 [nomen dubium]
Invalid names: Acichelys approximata Wagner 1856 [nomen dubium], Euryaspis radians Wagner 1861 [nomen dubium], Plesiochelys oblonga Oertel 1924 [nomen dubium], Plesiochelys pumilio Oertel 1924 [nomen dubium], Thalassemys heusseri Oertel 1924 [nomen dubium], Tropidemys morinica Sauvage 1880 [nomen dubium]
Diagnosis
No diagnoses are available
Measurements
No measurements are available
Composition: phosphaticsubp
Environment: terrestrialsubc
Locomotion: actively mobilec
Life habit: planktonicp
Diet: suspension feederp
Created: 2017-04-17 15:16:03
Modified: 2017-04-17 15:16:03
Source: subc = subclass, c = class, subp = subphylum, p = phylum
References: Kiessling 2004, Bambach et al. 2007, Carroll 1988, Hendy et al. 2009

Age range: base of the Callovian to the top of the MN 4 or 165.30000 to 15.98000 Ma

Collections (115 total)


Time interval Ma Country or state Original ID and collection number
Jurassic201.4 - 143.1Germany (Barvaria) Acichelys approximata (137802)
Middle Jurassic174.7 - 161.5China (Yunnan) Plesiochelys oshanensis (49502)
Callovian165.3 - 161.5Kyrgyzstan (Jalal-Abad) Plesiochelys sp. (37596)
Oxfordian161.5 - 154.8Portugal (Porto de Mos) Craspedochelys sp. (196750)
Middle Oxfordian - Early/Lower Kimmeridgian161.5 - 152.21Spain Hispaniachelys prebetica (140115)
Late/Upper Jurassic161.5 - 143.1China Plesiochelys kwanganensis (195440)
Early/Lower Kimmeridgian154.8 - 152.21Germany (Lower Saxony) Plesiochelys hannoverana, Tropidemys seebachi, Plesiochelys minor, Chelonides wittei, Stylemys lindenensis, Chelonides robusta (138029)
Early/Lower Kimmeridgian154.8 - 152.21Germany (Nordrhein-Westfalen) Tropidemys langii, Idiochelys fitzingeri, Eurysternum wagleri (182492)
Early/Lower Kimmeridgian154.8 - 152.21France (Haute-Normandie) Emys dollfusii, Plesiochelys normandica, Globochelus lennieri (60398) Tropidemys langii (219047)
Kimmeridgian154.8 - 149.2Germany (Bavaria) Thalassemys bruntrutana (207479)
Kimmeridgian154.8 - 149.2Poland (Zachodniopomorskie) Plesiochelys sp. (163141)
Kimmeridgian154.8 - 149.2France (Nord-Pas-de-Calais) Emys dutertrei (65033)
Kimmeridgian154.8 - 149.2United Kingdom (Oxfordshire) Thalassemys hugii (179854)
Kimmeridgian154.8 - 149.2Switzerland (Berne) Plesiochelys etalloni (137800)
Kimmeridgian154.8 - 149.2Portugal (Centro) Plesiochelyidae indet. (24563)
Kimmeridgian154.8 - 149.2Switzerland (Jura) Plesiochelys bigleri (200138) Plesiochelys sp., Tropidemys langii, Eurysternidae indet., Plesiochelys etalloni, Plesiochelys bigleri (154715) Plesiochelys sp., Tropidemys langii, Plesiochelys etalloni, Plesiochelys bigleri (154716) Tropidemys langii, Plesiochelys bigleri (154713)
Kimmeridgian154.8 - 149.2France Thalassemys hugii (131960)
Kimmeridgian - Early/Lower Tithonian154.8 - 145.06United Kingdom (England) Plesiochelys etalloni (140709) Tropidemys sp., Pelobatochelys blakei, Tropidemys langi (92096)
Kimmeridgian - Tithonian154.8 - 143.1Spain (Aragón) Plesiochelys sp., Plesiochelyidae indet. (58763)
Late/Upper Kimmeridgian152.21 - 149.2Germany (Baden-Württemberg) Eurysternum sp. (154138)
Late/Upper Kimmeridgian152.21 - 149.2Switzerland (Jura) Eurysternidae indet., Thalassemys bruntrutana (180789) Plesiochelys bigleri (149745) Plesiochelys sp., Tropidemys langii, Plesiochelys etalloni, Plesiochelys bigleri (154714) Portlandemys gracilis (171092 171093) Thalassemys hugii, Eurysternidae indet. (180788) Tropidemys langii, Solnhofia brachyrhyncha (154717)
Late/Upper Kimmeridgian152.21 - 149.2Germany (Eastern Bavaria) Eurysternidae indet. (187436)
Late/Upper Kimmeridgian152.21 - 149.2Switzerland (Solothurn) Thalassemys hugii, Plesiochelys solodurensis, Thalassemys moseri, Plesiochelys jaccardi, Tropidemys langi (90875) Tropidemys sp., Thalassemys hugii, Plesiochelys solodurensis, Solnhofia parsonsi, Craspedochelys picteti, Craspedochelys crassa, Plesiochelys langii, Plesiochelys sanctaverenae, Thalassemys gresslyi, Eurysternum ignoratum, Tropidemys langi, Tropidemys expansa, Tropidemys gibba, Craspedochelys plana, Thalassemys bruntrutana, Emys hugi, Emys hugii, Emys trionychoides, Emys jurensis, Plesiochelys etalloni, Thalassemys moseri (137749)
Late/Upper Kimmeridgian152.21 - 149.2Poland (Ilza) Tretosternon punctatum (123852)
Late/Upper Kimmeridgian152.21 - 149.2France Idiochelys fitzingeri, Chelone meyeri, Achelonia formosa, Chelonemys ovata, Chelonemys plana (24426) Plesiochelyidae indet. (138010)
Late/Upper Kimmeridgian152.21 - 149.2Germany (Bavaria) Eurysternum wagleri, Tropidemys seebachi, Achelonia formosa (132944)
Late/Upper Kimmeridgian152.21 - 149.2Germany (Niedersachsen) Plesiochelys oblonga, Plesiochelys pumilio, Thalassemys heusseri (149723)
Late/Upper Kimmeridgian152.21 - 149.2Portugal (Centro) Craspedochelys jaccardi (138023)
Late/Upper Kimmeridgian152.21 - 149.2Germany (Bayern) Eurysternum wagleri (130048) Idiochelys fitzingeri, Palaeomedusa testa, Idiochelys wagneri, Plesiochelys minima, Eurysternum crassipes (57682) Solnhofia parsonsi, Eurysternidae indet., Eurysternum wagleri (59175)
Late/Upper Kimmeridgian152.21 - 149.2France (Nord-Pas-de-Calais) Tropidemys morinica (67107)
Late/Upper Kimmeridgian152.21 - 149.2France (Aquitaine) Plesiochelys hannoverana, Tropidemys gibba (94532)
Late/Upper Kimmeridgian152.21 - 149.2France (Lot) Craspedochelys 'squat form' (138014 138018) Craspedochelys jaccardi (138016) Plesiochelyidae indet. (138009 138011 138012 138013) Solnhofia parsonsi (138017)
Late/Upper Kimmeridgian152.21 - 149.2United Kingdom (England) Thalassemys sp. (167731) Tholemys passmorei (138007)
Late/Upper Kimmeridgian - Early/Lower Tithonian152.21 - 145.06Spain (Aragón) Plesiochelyidae indet., Tropidemys sp. (53890)
Late/Upper Kimmeridgian - Early/Lower Tithonian152.21 - 145.06Portugal (Centro) Tropidemys sp. (167730)
Late/Upper Kimmeridgian - Tithonian152.21 - 143.1Spain (Teruel) Plesiochelyidae indet. (58770)
Early/Lower Tithonian149.2 - 145.06Switzerland (Canton de Neuchâtel) Emys jaccardi (138021)
Early/Lower Tithonian149.2 - 145.06France (Provence-Alpes-Côte d'Azur) Plesiochelyidae indet., Eurysternum sp., Solnhofia sp. (35262)
Early/Lower Tithonian149.2 - 145.06France (Jura) Plesiochelys etalloni (137799)
Early/Lower Tithonian149.2 - 145.06Germany (Bavaria) Solnhofia parsonsi (212955) Solnhofia parsonsi, Eurysternum wagleri (58604)
Early/Lower Tithonian149.2 - 145.06France (Oléron Island) Jurassichelon oleronensis (167752)
Early/Lower Tithonian149.2 - 145.06Germany (Bayern) Eurysternum wagleri (81855 106543 123985) Solnhofia parsonsi (53036 212952) Solnhofia parsonsi, Eurysternum wagleri, Thalassochelydia indet. (144679) Testudinata new species? (123906)
Early/Lower Tithonian149.2 - 145.06Argentina (Neuquén) Eurysternum neuquinum, Neusticemys neuquina (79651)
Early/Lower Tithonian149.2 - 145.06France (Poitou-Charentes) Plesiochelyidae indet., Eurysternum sp. (164377)
Early/Lower Tithonian149.2 - 145.06Portugal (Lisboa) Plesiochelyidae indet. (49262)
Early/Lower Tithonian149.2 - 145.06Germany Parachelys eichstaettensis (121197)
Early/Lower Tithonian149.2 - 145.06Germany (Land Bayern) Euryaspis radians (137801)
Early/Lower Tithonian - Late/Upper Tithonian149.2 - 143.1Argentina (Neuquén) Eurysternum neuquinum, Neusticemys neuquina (79652)
Middle Tithonian - Late/Upper Tithonian149.2 - 143.1Portugal (Centro) Hylaeochelys kappa (153564) Plesiochelys sp. (184944)
Tithonian149.2 - 143.1Portugal (Torres Verdes) Plesiochelys sp. (219477)
Tithonian149.2 - 143.1Portugal (Torres Verdas) Plesiochelys sp. (219478)
Tithonian149.2 - 143.1France (Nord-Pas-de-Calais) Plesiochelys sp., Tropidemys sp. (53967)
Tithonian149.2 - 143.1Germany (Franconia) Palaeomedusa testa (24521)
Tithonian149.2 - 143.1Portugal Plesiochelyidae indet. (55235)
Tithonian149.2 - 143.1France (Lot) Craspedochelys jaccardi (138015) Plesiochelyidae indet. (138019)
Tithonian149.2 - 143.1Argentina (Neuquen) Neusticemys neuquina (206016)
Tithonian149.2 - 143.1Ethiopia Plesiochelyidae indet. (204301)
Tithonian149.2 - 143.1United Kingdom (England) Chelone planiceps (137747) Stegochelys planiceps (137748)
Tithonian149.2 - 143.1Portugal (Lisbon) Plesiochelys choffati (189389)
Late/Upper Tithonian145.06 - 143.1United Kingdom (England) Portlandemys sp., Stegochelys planiceps (119505)
Late/Upper Tithonian145.06 - 143.1Argentina (Neuquén) Neusticemys neuquina (122661 140285)
Late/Upper Tithonian - Early/Lower Berriasian145.06 - 141.0France (Nord-Pas-de-Calais) Plesiochelys sp. (92145) Plesiochelys sp., Tropidemys sp. (92144)
Berriasian143.1 - 137.05France (Poitou-Charentes) Plesiochelyidae indet., Hylaeochelys belli (142093)
Berriasian143.1 - 137.05United Kingdom (England) Hylaeochelys latiscutata (127480) Plesiochelys sp. (92916) Pleurosternon latiscutatum (127481) Thalassochelydia indet. (127478)
Early/Lower Cretaceous143.1 - 100.5Spain (Castilla y Leon) Testudines indet. (64406)
Early/Lower Valanginian137.05 - 132.6Switzerland Chelonia valanginensis (2225)
Early/Lower Valanginian137.05 - 132.6United Kingdom (England) Hylaeochelys belli (127529)
Late/Upper Valanginian137.05 - 132.6United Kingdom (England) Chelone belli, Platemys mantelli, Platemys dixoni, Archaeochelys valdensis, Plesiochelys sp. (52258)
Valanginian137.05 - 132.6United Kingdom (England) Hylaeochelys latiscutata (127535)
Hauterivian132.6 - 125.77Colombia (Guajira) Craspedochelys renzi (242132)
Late/Upper Hauterivian132.6 - 125.77United Kingdom (England) Plesiochelys sp. (22700)
Early/Lower Aptian121.4 - 119.57Switzerland Chelonia valanginiensis (167361)
Early/Lower Aptian121.4 - 119.57United Kingdom (England) Tropidemys sp. (167728)
Late/Upper Aptian119.57 - 113.2Uzbekistan (Karakalpakstan) Plesiochelyidae sp. (58465)
Late/Upper Albian - Cenomanian106.3 - 93.9Uzbekistan (Navoi) Thalassemydidae indet. (58471)
Middle Cenomanian - Late/Upper Cenomanian100.5 - 93.9Germany Hydropelta sp. (74183)
MN 416.9 - 15.98Spain (Catalonia) Parachelys catalaunica (176265)