Testudinata Klein, 1760

Cadena, Edwin-Alberto, Carrillo-Briceño, Jorge D., Bastiaans, Dylan, Fairbanks-Freund, Tandra, Costeur, Loïc & Scheyer, Torsten M., 2025, The first occurrence of “ PleSioCHelyidae ” marine turtles in the early cretaceous of South America, Swiss Journal of Palaeontology (52) 144 (1), pp. 1-12 : 5-8

publication ID	https://doi.org/10.1186/s13358-025-00394-1
persistent identifier	https://treatment.plazi.org/id/3C3F7E38-FFEB-FF82-FF36-D2ABFE8840B2
treatment provided by	Felipe
scientific name	Testudinata Klein, 1760
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Treatment

Testudinata Klein, 1760 ; sensu Joyce et al., 2020 Talassochelydia Anquetin et al., 2017

“ Plesiochelyidae ” Baur, 1888; sensu Anquetin et al., 2017

Craspedochelys Rütimeyer, 1873

Craspedochelys renzi sp. nov.

( Figs. 3 View Fig , 4 View Fig , 6 View Fig ).

Etymology. In honor of the Swiss geologist Otto Renz, who discovered and collected the fossil turtle Otto Rentz’s legacy also includes important geological and paleontological studies of the Cretaceous of Colombia and Venezuela ( Renz, 1982, and references therein).

Holotype. NMB SA.M.19 partially preserved articulated shell (bone component of the posterior carapace, infilled of the mid-anterior carapacial cavity, and nearly complete plastron); most of its right hindlimb bones including the femur, the tibia, the fibula, autopodium bones; some bones of the left hindlimb including the femur and a fibula? portion; both pubes and right ischium; and at least six caudal vertebrae.

Type locality and horizon. “ E” section (between 11º53 ′ 50.87’’N, 71º44 ′ 08.23’’W and 11º53 ′ 41.64’’N, 71º43 ′ 20.11’’W) ( Fig. 1B, C View Fig ) Moina Fm. following Renz (1960), Cuña de Cuiza , Guajira Department, Colombia GoogleMaps

( Fig. 2A View Fig ). Indeterminate stratigraphic horizon ( Fig. 2D View Fig ).

Diagnosis. Craspedochelys renzi shares the following combination of characteristics with other thalassochelyians, particularly with members of “ Plesiochelyidae ”: (1) a V-shaped posterior plastral lobe, reduced in length and without anal notch; (2) an indentation of the sutural contact between the hypoplastra and xiphiplastra; (3) occurrence of an "intermediate" bone between the last neural (neural 8) and suprapygal 1; 4) completely ossified carapace and bridge to the plastron, and (5) lack of carapacial fontanelles. Inside “ Plesiochelyidae ”, it is attributable to Craspedochelys and excluded from Plesiochelys by: (1) a broader carapace, which appears to have been approximately as wide as it was long, as indicated by an estimated (as preserved) length/width ratio of 4.12 (103/ 25 mm) for the left costal 4—similar to other species of the genus with values greater than 4 ( Anquetin et al., 2014, Table 3); (2) a relatively shorter plastron, and (3) proportionally wider hyoplastra. It is excluded from being part of Tropidemys by (1) its wider vertebral scutes, and (2) absence of neural keels. It differs from all other “plesiochelyids” by (1) suprapygal 2 small and in a nearly triangle shape, instead of being trapezoidal or pentagonal, and in posterior contact only with the pygal, without reaching the posterior-most peripheral bones, and (2) from all other the specimens of Craspedochelys spp. , by exhibiting an incomplete neural series, where costals 7 meet medially, but costals 8 are separated by an isolated neural, potentially neural 8.

Description.—Te shell of Craspedochelys renzi sp. nov. is three-dimensionally preserved thanks to the rock matrix that created a cast of its internal cavity ( Fig. 3 View Fig ). As preserved, the shell measures 25.5 cm in length and 23.1 cm in width. Te cortical bone of both carapace and plastron exhibits a smooth to slightly eroded surface in some regions.

Carapace. Te original bony component of the carapace is preserved only at the most posterior part, with some missing portions of the left peripherals. A rock matrix cast of the mid-anterior portions of the carapace preserves, in anatomical position, parts of the axillary buttresses and the medial rib projections of the costals, indicating that there were eight pairs of costals. Te most ventral portions of the thoracic ribs are also preserved along the midline of the carapacial cast ( Fig. 3A, B View Fig ). Although the complete shape of the carapace is not possible to establish, as preserved, it is evident that it was nearly as wide as long. Te neural series is interrupted by a medial contact of costals 7. A neural bone is located right before the intermediate bone, possibly neural 8?. Two neurals, possibly 5 and 6? are nearly hexagonal and restricted between costals 5 to 7, suggesting that neural 7 is absent in the specimen or at least not expressed dorsally. Te intermediate bone is nearly trapezoidal in shape and restricted between costals 8, suprapygal 1 and neural 8?. Tere are two suprapygal bones, being suprapygal 1 the larger and exhibiting an elongated hexagonal shape. Te suprapygal bone 2 is triangular and restricted between the suprapygal 1 and the pygal. Most of the posterior edge of the pygal bone is missing. Te preserved costal bones (5 to 8) are rectangular elongated, slightly longer at their lateral edges. Tis seems to be the case also for the fully eroded costals 2 to 4, as some portions of the sutural contacts between them are preserved as scars in the rocky cast, in the particular case of the left costal 4, it has an estimated preserved length of 103 mm and a width of 25 mm. Te posterior peripherals 7 to 11 of both sides are preserved, squared in shape and most of them with their lateral edges broken, especially those from the left side. Te sulci left by vertebral scutes 4 and 5 indicate that both were hexagonal in shape, much wider than long. Pleural scute 4 was trapezoidal in shape and much narrower than pleural scute 3. Marginal scutes were restricted to the peripherals, without reaching the costals.

Plastron. Te plastron of C. renzi sp. nov. is nearly complete, missing only the most anterior portions of the anterior lobe, including the entoplastron and epiplastra. It measures 19.2 cm in length and 19.8 cm in width as preserved ( Fig. 3C, D View Fig ). Te posterior plastral lobe exhibits a V-shape, lacking a medial anal notch. Each xiphiplastron has a nearly triangular shape, with an indentation at the sutural contact with the hypoplastron, near the lateral region of the bone. Te hypoplastra are highly sutured to the carapace laterally and meet each other medially without the presence of fontanelles. Te hyoplastra are the largest bones of the plastron. Additionally, the hyoplastra are flat, meet medially, and are strongly sutured to the peripherals laterally. Te anterior-most margins of the hyoplastra are broken and indicate that the missing entoplastron was a small bone located very anteriorly in the anterior plastral lobe. Te sulci left by the plastral scutes are marked on the bones and indicate that the anals were restricted to the xiphiplastral, the femorals were the longest scutes, the abdominals the shortest medially. Tere is an indication of at least three lateral inframarginal scutes in both sides of the plastron.

Postcranial. Several postcranial bones are preserved in C. renzi sp. nov. ( Fig. 4 View Fig ). Tey are only mentioned here as a more detailed description based on CT scan analysis that will be presented in a separate publication currently in progress. Te postcranial bones exposed after preparation of the specimen include both femora, portions of both fibulae, the right tibia, and the right ischium and pubis. Most of the elements of the right pes are also preserved, including three distal tarsals and five metatarsals. Additionally, at least six caudal vertebrae are preserved, nearly articulated.