Compsemydidae

Compsemydidae Temporal range: Berriasian–Thanetian PreꞒ Ꞓ O S D C P T J K Pg N Possible Late Jurassic records
Fossil of Peltochelys duchastelii
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Pantestudines
Clade:	Testudinata
Clade:	†Paracryptodira
Family:	†Compsemydidae Pérez-García et al., 2015
Genera
See text

Compsemydidae is an extinct family of turtles, likely belonging to the clade Paracryptodira. The earliest undisputed member is Tongemys from the Berriasian age of the Early Cretaceous; two Late Jurassic genera (Riodevemys and Selenemys) have also sometimes been included in the group,[1] but may alternatively be members of the family Pleurosternidae.[2] The genus Compsemys survived the Cretaceous–Paleogene extinction event and lasted until the Thanetian age of the Paleocene.[3]

Taxonomy

Compsemydidae was named in a 2015 paper by Pérez-García et al., who included the type genus Compsemys and its possible synonym Berruchelus.[4] A 2020 paper by Joyce and Rollot expanded the family to include the enigmatic Peltochelys from the Early Cretaceous, as well as the Late Jurassic Riodevemys and Selenemys that had earlier been placed in Pleurosternidae.[1] A 2021 paper by Rollot et al. added the Late Cretaceous Kallokibotion to the family, but moved Riodevemys back into Pleurosternidae.[5] 2022 saw the description of two new compsemydids, the Early Cretaceous Tongemys and the Late Cretaceous Calissounemys, by Joyce et al. and Tong et al. respectively.[6][7]

Joyce & Rollot (2020) defined Compsemyidae as "the most inclusive group of turtles that includes Compsemys victa but not the baenid Baena arenosa Leidy, 1870, the pleurosternid Pleurosternon bullockii (Owen, 1842), or any extant turtle".[1]

Genera

• Berruchelus France, Paleocene (some authors include this genus within Compsemys)[8]
• Calissounemys Var, France, Late Cretaceous (Campanian)[7]
• Compsemys North America, Europe, Late Cretaceous–Palaeocene
• Kallokibotion? Hațeg Basin, Romania, Late Cretaceous (Maastrichtian)[5]
• Peltochelys Sainte-Barbe Clays Formation, Belgium, Early Cretaceous (Barremian)[3]
• Riodevemys? Villar del Arzobispo Formation, Spain, Late Jurassic (Tithonian)[1]
• Selenemys? Lourinhã Formation, Portugal, Late Jurassic (Kimmeridgian)[3]
• Tongemys Purbeck Group, England, Early Cretaceous (Berriasian)[6]

Phylogeny

A phylogenetic analysis by Pérez-García et al. (2015) found Compsemydidae to be the most basal (early-diverging) group within Paracryptodira, lying outside Baenoidea, the clade formed by Baenidae and Pleurosternidae.[4] Rollot et al. (2021) instead found Compsemydidae to be more closely related to traditional baenids than to pleurosternids, thus making Compsemydidae a subgroup of Baenidae by definition.[5] Rollot & Joyce (2022) recovered compsemydids as early-diverging paracryptodires when using implied weighting, but the group was placed in a polytomy with Paracryptodira and several other turtle genera when equal weighting was used.[3]

The cladogram below follows the implied weighting analysis of Rollot & Joyce (2022), with the rogue taxa Pleurosternon moncayensis and Scabremys ornata removed:[3]

Paracryptodira	Compsemydidae Kallokibotion bajazidi Selenemys lusitanica Peltochelys duchastelii Compsemys russelli Compsemys victa Helochelydridae Dinochelys whitei Glyptops ornatus Dorsetochelys typocardium Uluops uluops Baenoidea Baenidae Pleurosternidae

References

1. Joyce, W. G.; Rollot, Y. (2020). "An alternative interpretation of Peltochelys duchastelii as a paracryptodire". Fossil Record. 23 (1): 83–93. Bibcode:2020FossR..23...83J. doi:10.5194/fr-23-83-2020.
2. Pérez-García, A.; Martín-Jiménez, M.; Aurell, M.; Canudo, J. I.; Castanera, D. (2022). "A new Iberian pleurosternid (Jurassic-Cretaceous transition, Spain) and first neuroanatomical study of this clade of stem turtles". Historical Biology. 34 (2): 298–311. Bibcode:2022HBio...34..298P. doi:10.1080/08912963.2021.1910818.
3. Rollot, Y.; Evers, S. W.; Pierce, S. E.; Joyce, W. G. (2022). "Cranial osteology, taxonomic reassessment, and phylogenetic relationships of the Early Cretaceous (Aptian-Albian) turtle Trinitichelys hiatti (Paracryptodira)". PeerJ. 10: e14138. doi:10.7717/peerj.14138. PMC 9636874. PMID 36345484.
4. Pérez-García, A.; Royo-Torres, R.; Cobos, A. (2015). "A new European Late Jurassic pleurosternid (Testudines, Paracryptodira) and a new hypothesis of paracryptodiran phylogeny". Journal of Systematic Palaeontology. 13 (4): 351–369. Bibcode:2015JSPal..13..351P. doi:10.1080/14772019.2014.911212.
5. Rollot, Y.; Evers, S. W.; Joyce, W. G. (2021). "A redescription of the Late Jurassic (Tithonian) turtle Uluops uluops and a new phylogenetic hypothesis of Paracryptodira". Swiss Journal of Palaeontology. 140 (1): 23. Bibcode:2021SwJP..140...23R. doi:10.1186/s13358-021-00234-y. ISSN 1664-2376. PMC 8550081. PMID 34721284.
6. Joyce, W. G.; Bourque, J. R.; Fernandez, V.; Rollot, Y. (2022). "An alternative interpretation of small-bodied turtles from the "Middle Purbeck" of England as a new species of compsemydid turtle". Fossil Record. 25 (2): 263–274. Bibcode:2022FossR..25..263J. doi:10.3897/fr.25.85334. S2CID 251659402.
7. Tong, H.; Tortosa, T.; Buffetaut, E.; Dutour, Y.; Turini, E.; Claude, J. (2022). "A compsemydid turtle from the Upper Cretaceous of Var, southern France". Annales de Paléontologie. 108 (1): 102536. Bibcode:2022AnPal.10802536T. doi:10.1016/j.annpal.2022.102536.
8. Pérez-García, A. (2012). "Berruchelus russelli, gen. et sp. nov., a paracryptodiran turtle from the Cenozoic of Europe". Journal of Vertebrate Paleontology. 32 (3): 545–556. Bibcode:2012JVPal..32..545P. doi:10.1080/02724634.2012.658933. ISSN 0272-4634.