''Leyvachelys'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

s in the family Sandownidae from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

( Late Aptian to Early Albian) of the present-day

Altiplano Cundiboyacense The Altiplano Cundiboyacense () is a high plateau located in the Eastern Cordillera of the Colombian Andes covering parts of the departments of Cundinamarca and Boyacá. (Do not confuse with The Altiplano or the Altiplano Nariñense, both fur ...

, Eastern Ranges,

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The genus is known only from its

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, ''Leyvachelys cipadi'', described in

2015 2015 was designated by the United Nations as: * International Year of Light * International Year of Soil __TOC__ Events January * January 1 – Lithuania officially adopts the euro as its currency, replacing the litas, and becomes ...

by Colombian paleontologist Edwin Cadena. Fossils of ''Leyvachelys'' have been found in the fossiliferous Paja Formation, close to Villa de Leyva, Boyacá, after which the genus is named. The holotype specimen is the oldest and most complete sandownid turtle found to date. Fossils of a turtle found in the dinosaur-rich Glen Rose Formation of

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, informally named ''Glenrosechelys brooksi'', have been assigned to the same genus and type species.

Etymology

The genus name is derived from Villa de Leyva and ''chelys'' means "turtle" in

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

. The species

epithet An epithet (, ), also a byname, is a descriptive term (word or phrase) commonly accompanying or occurring in place of the name of a real or fictitious person, place, or thing. It is usually literally descriptive, as in Alfred the Great, Suleima ...

''cipadi'' refers to the CIP; the Centro de Investigaciones Paleontológicas, the paleontological research centre outside Villa de Leyva.

Description

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was found on the Loma La Catalina, west of Villa de Leyva,

in 2009. The fossil was discovered in a layer of calcareous

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...

with abundant occurrences of ferruginous-calcareous nodules and concretions. The section belongs to the middle segment of the Paja Formation called "Arcillolitas abigarradas Member" and has been dated on the basis of

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

s to be Late Barremian to Early Aptian in age.Cadena, 2015a The turtle is the earliest recorded sandownid turtle in the world and the first of this family discovered in South America. The fossil find consists of a fairly complete skull, a well-preserved lower jaw and postcrania with an almost complete

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

, three cervical vertebrae, right humerus and coracoid, both femora,

tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...

e, and pelvic girdle. The length of the skull is estimated at and the maximum size of the carapace has been reported as . The carapace of ''L. cipadi'' is the first complete ever found for a sandownid.

Habitat

The

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...

to Late Aptian Paja Formation is one of the richest fossiliferous stratigraphic units of Colombia, where other marine reptiles are found too. Pliosaurs as '' Kronosaurus'' and '' Stenorhynchosaurus'',

ichthyosaur Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of the Mesozoic era; based on fo ...

s as '' Muiscasaurus'' and ''

Platypterygius ''Platypterygius'' is a historically paraphyletic genus of platypterygiine ichthyosaur from the Cretaceous period. It was historically used as a wastebasket taxon, and most species within ''Platypterygius'' likely are undiagnostic at the genus or ...

'' and a

plesiosaur The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...

s known as '' Callawayasaurus'' represent the known marine reptile fauna assemblage of the formation. From the Paja Formation in the same year as ''Leyvachelys'', the oldest sea turtle known in the world, '' Desmatochelys padillai'',Cadena & Parham, 2015b, p.1 has been reported. The habitat of ''Leyvachelys'' is described as

littoral The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely i ...

, not open marine as is the case for ''Desmatochelys''. Additionally, many different

s and

crustacea Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

ns are described from the formation.Kabakadze & Hoedemaeker, 1997Bermúdez et al., 2013 The morphology of the shell of ''L. cipadi'', allows the support of previously hypothesized habitat adaptations for sandownids; in particular, that they inhabited

to near-shore shallow marine environments, and that their general body-plan was not designed for leading an open marine lifestyle. They nevertheless potentially shared niches with open marine turtles, as evidenced by the occurrence of protostegids as ''Desmatochelys'', from the same stratigraphical horizons. The abundant occurrence of molluscs, principally ammonites, some of them preserved associated with the carapace of ''L. cipadi'', suppose a potential source of food for its durophagous diet adaptation which could have also included arthropods, as for example crabs. Fossil turtle fragments, initially and informally described as ''Glenrosechelys brooksi'', found in the contemporaneous to slightly younger Glen Rose Formation of Texas have been assigned to the same genus ''Leyvachelys''. Both occurrences in Texas (paleocoordinates 30.0° N, 55.5° W),SMU 246
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org and Colombia (paleocoordinates 3.6° N, 42.2° W)Loma La Catalina
at

.org represent the northern and southern paleocoastline of the Early Cretaceous proto-Caribbean Sea.

References

Bibliography

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External links