Mesochelydia (from
Greekmesos "middle" and chelys "turtle") is a
clade within
Pantestudines, more inclusive than
Perichelydia, but less than
Testudinata. The clade is known from the Early Jurassic to the Present, and contains all Jurassic representatives of Testudinata aside from Australochelys.[1] The ancestral condition for Mesochelydia is thought to be aquatic, as opposed to terrestrial for Testudinata.[2] They are distinguished from more basal testudinatans by the presence of the following characters: strap like
pectoral girdle, supramarginals absent, reduced posterior entoplastral process, eleven pairs of peripherals, elongate processus interfenestralis, paired basioccipital tubercles, fully formed
cavum tympani and antrum postoticum, single
vomer, confluent external
nares,
lacrimals and
supratemporals absent.[1]
^
abJoyce, Walter G. (April 2017). "A Review of the Fossil Record of Basal Mesozoic Turtles". Bulletin of the Peabody Museum of Natural History. 58 (1): 65–113.
doi:
10.3374/014.058.0105.
ISSN0079-032X.
S2CID54982901.
^Sterli, Juliana; de la Fuente, Marcelo S.; Rougier, Guillermo W. (2018-07-04). "New remains of Condorchelys antiqua (Testudinata) from the Early-Middle Jurassic of Patagonia: anatomy, phylogeny, and paedomorphosis in the early evolution of turtles". Journal of Vertebrate Paleontology. 38 (4): (1)–(17).
doi:
10.1080/02724634.2018.1480112.
ISSN0272-4634.
S2CID109556104.
^V. B. Sukhanov. 2006. An archaic turtle, Heckerochelys romani gen. et sp. nov. from the Middle Jurassic of Moscow region, Russia. Fossil Turtle Research1:112-118
^Skutschas, Pavel P.; Markova, Valentina D.; Kolchanov, Veniamin V.; Averianov, Alexander O.; Martin, Thomas; Schellhorn, Rico; Kolosov, Petr N.; Grigoriev, Dmitry V.; Vitenko, Dmitry D.; Obraztsova, Ekaterina M.; Danilov, Igor G. (February 2020). "Basal turtle material from the Lower Cretaceous of Yakutia (Russia) filling the gap in the Asian record". Cretaceous Research. 106: 104186.
doi:
10.1016/j.cretres.2019.07.016.
S2CID202195840.