Discosauriscus juvenile with soft tissue preserved + Elkanemys caelestis, new turtle species from Cretaceous of Argentina + gliding lizard aerodynamics + amniote limb structure trabecular diversity
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Ben Creisler
Nov 6, 2025, 2:22:32 PM (5 days ago) Nov 6
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Ben Creisler
Recent tetrapod papers:
Free pdf:
Antoine LOGGHE, Arnaud REBILLARD, Guillaume HOUÉE, Alicia SÁNCHEZ GIMENO, Erwan COURVILLE, Lazare ELBAZ, Paloma-Maria TARABA, Rodolphe PASO, Max HERDE, Stanislav ŠTAMBERG, Jean-Marc POUILLON & J.-Sébastien STEYER (2025)
Palaeoecology and palaeoenvironment of Discosauriscus Kuhn, 1933 with exceptional preservation of skin and intestine molds from the early Permian of Franchesse (Allier, France)
Comptes Rendus Palevol 24(24): 489-504
doi: https://doi.org/10.5852/cr-palevol2025v24a24
https://sciencepress.mnhn.fr/en/periodiques/comptes-rendus-palevol/24/24
Free pdf:
https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/comptes-rendus-palevol2025v24a24.pdf
The Carboniferous-Permian is a key period concerning the emergence and diversification of major tetrapod clades such as amphibians and amniotes. This is particularly the case of the Seymouriamorpha Watson, 1917. Some seymouriamorphs are well-known, such as Seymouria Broili, 1904 from North America and Germany, but the ecology of most taxa remains debated. This is the case of Discosauriscus Kuhn, 1933 from the early Permian of Europe. Here we provide a preliminary study of new specimens from the early Permian Lagerstätte of Franchesse (Allier, France) whose exceptionally well-preserved soft tissues including skin and intestinal casts provide valuable insights into the palaeoecology of Discosauriscus. We describe for the first time the complete skin external and histological features of a seymouriamorph indicating that juvenile discosauriscids already displayed epidermal scalation. This suggests a skin adapted towards terrestrial lifestyle in juvenile Discosauriscus. The recovery of an in situ cololite facilitates the identification of seymouriamorph coprolites found ex situ, and thus, future interpretations of the specific diet of this taxon. In order to better understand how these soft tissues have been preserved, we also conducted a taphonomic study including a stratigraphic and palaeoenvironmental analysis of the fossil layer deposits. Our results suggest that pronounced volcanic activity at work during the early Cisuralian of the Bourbon-l’Archambault Basin may be the cause of the multiple Permian mass mortality assemblages found at Franchesse, as well as the exceptional preservation of the fossil remains from this site.
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Elkanemys caelestis sp. nov.
Mariana Sarda & Ignacio J. Maniel (2025)
A new species of Elkanemys (Pleurodira: Pelomedusoides) from the Portezuelo Formation (Turonian–Coniacian) of Patagonia, Argentina
Journal of Systematic Palaeontology 23(1): 2572329
doi: https://doi.org/10.1080/14772019.2025.2572329
https://www.tandfonline.com/doi/full/10.1080/14772019.2025.2572329
We describe Elkanemys caelestis sp. nov., a pelomedusoid turtle, based on two specimens from the Baal locality, Portezuelo Formation (Turonian-Coniacian), situated on the northern shore of Barreales Lake, Neuquén Province, Argentina. Specimens MUC-Pv 2218 and MUC-Pv 2219 represent two individuals, preserving both the carapace and plastron articulated by the bridge, showing characteristics of Pelomedusoides within Pleurodira, such as absence of a cervical scute, lateral rounded mesoplastra and a wide posterior plastral lobe. MUC-Pv 2219 also preserves the skull which exhibits characteristics typical of Pelomedusoides such as the presence of a quadratojugal bone and the absence of nasal bones. The carapace of MUC-Pv 2219 exhibits an anomaly of supernumerary peripheral bones and marginal scutes. Furthermore, MUC-Pv 2219 presents a unique indeterminate sub-triangular bone element ventral to the dentary, which is not described in other Cretaceous pleurodires. Both specimens demonstrate shared features, including hexagonal first neurals with short posterolateral sides and quadrangular second neurals, reinforcing their placement within the genus Elkanemys. Our phylogenetic analysis recovers Elkanemys as a member of Podocnemidoidae, exhibiting close affinities with Bauru Basin species.
A new species of Elkanemys (Pleurodira: Pelomedusoides) from the Portezuelo Formation (Turonian–Coniacian) of Patagonia, Argentina
Journal of Systematic Palaeontology 23(1): 2572329
doi: https://doi.org/10.1080/14772019.2025.2572329
https://www.tandfonline.com/doi/full/10.1080/14772019.2025.2572329
We describe Elkanemys caelestis sp. nov., a pelomedusoid turtle, based on two specimens from the Baal locality, Portezuelo Formation (Turonian-Coniacian), situated on the northern shore of Barreales Lake, Neuquén Province, Argentina. Specimens MUC-Pv 2218 and MUC-Pv 2219 represent two individuals, preserving both the carapace and plastron articulated by the bridge, showing characteristics of Pelomedusoides within Pleurodira, such as absence of a cervical scute, lateral rounded mesoplastra and a wide posterior plastral lobe. MUC-Pv 2219 also preserves the skull which exhibits characteristics typical of Pelomedusoides such as the presence of a quadratojugal bone and the absence of nasal bones. The carapace of MUC-Pv 2219 exhibits an anomaly of supernumerary peripheral bones and marginal scutes. Furthermore, MUC-Pv 2219 presents a unique indeterminate sub-triangular bone element ventral to the dentary, which is not described in other Cretaceous pleurodires. Both specimens demonstrate shared features, including hexagonal first neurals with short posterolateral sides and quadrangular second neurals, reinforcing their placement within the genus Elkanemys. Our phylogenetic analysis recovers Elkanemys as a member of Podocnemidoidae, exhibiting close affinities with Bauru Basin species.
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Free pdf:
Erik A. Sathe & Robert Dudley (2025)
Forelimb motion and reciprocation mediate aerodynamic control in a gliding lizard
BMC Ecology and Evolution 25: 117
doi: https://doi.org/10.1186/s12862-025-02419-2
https://link.springer.com/article/10.1186/s12862-025-02419-2
Background
The origin of the flight stroke in vertebrate flight evolution remains obscure. However, using forelimbs to control aerodynamic forces while gliding provides a possible exaptation from which wingless taxa evolved incipient wing flapping and powered flight. We used flat-tailed house geckos (Hemidactylus platyurus) to model the possible dynamics of those gliding taxa ancestral to vertebrate flyers, and characterized their limb and body kinematics while gliding in a vertical wind tunnel, so as to determine biomechanical consequences of forelimb movements during controlled aerial behavior.
Results
Geckos mostly assumed a stereotypical skydiving posture but intermittently would flex the body ventrally as the forelimbs were retracted posteriorly. Shoulder retraction, spinal column flexion, and subsequent translational velocity in the vertical and cranial directions were positively correlated; such alteration of body posture with simultaneous forelimb displacement thus modulates the directions and magnitudes of aerodynamic forces, including horizontal thrust production. Independent of shoulder retraction and body bend, body pitch correlated positively with vertical acceleration and negatively with horizontal acceleration.
Conclusions
Gliding geckos actively use their forelimbs to alter body speed and to generate thrust, suggesting aerodynamic function for limb displacement and reciprocation in the absence of wings. Prior to the origin of the flapping of winglike structures, analogous forelimb motions (including symmetric reciprocation) may have thus provided biomechanical advantage in the evolution of volant vertebrates.
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Tristan E Reinecke & Kenneth D Angielczyk (2025)
Exploring functional and phylogenetic variation in limb trabecular structure across amniote taxa
Biological Journal of the Linnean Society 146(3): blaf073,
doi: https://doi.org/10.1093/biolinnean/blaf073
https://academic.oup.com/biolinnean/article-abstract/146/3/blaf073/8312934
Trabecular bone, a lattice of bony struts located within the cortical shell of many skeletal elements, plays a pivotal role in skeletal support by adjusting its architecture to withstand compressive forces. Research on trabecular morphology historically has concentrated on primates, with comparatively limited focus on other clades or on broad analysis of higher-order groups. In this study, we investigate the trabecular architecture of a diverse range of terrestrial amniote taxa to examine how size, phylogenetic context, ecomorphology, and posture influence trabecular development in two limb elements. This comparative analysis was made possible by establishing a uniform orientation method that can be applied to other amniote taxa. Our results demonstrate clear differences between the trabeculae of the humerus and femur in mammals that are not seen in reptiles. Although ecological niche and postural groups have limited influence on most traditional trabecular metrics, our results highlight striking differences in trabecular orientation between these groups. Posture was correlated with trabecular orientation, probably stemming from the varied angle of limbs and the resulting directions of stress exerted during locomotion. Future research into non-primate taxa should incorporate trabecular orientation to gain a better understanding of trabecular diversity.
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Exploring functional and phylogenetic variation in limb trabecular structure across amniote taxa
Biological Journal of the Linnean Society 146(3): blaf073,
doi: https://doi.org/10.1093/biolinnean/blaf073
https://academic.oup.com/biolinnean/article-abstract/146/3/blaf073/8312934
Trabecular bone, a lattice of bony struts located within the cortical shell of many skeletal elements, plays a pivotal role in skeletal support by adjusting its architecture to withstand compressive forces. Research on trabecular morphology historically has concentrated on primates, with comparatively limited focus on other clades or on broad analysis of higher-order groups. In this study, we investigate the trabecular architecture of a diverse range of terrestrial amniote taxa to examine how size, phylogenetic context, ecomorphology, and posture influence trabecular development in two limb elements. This comparative analysis was made possible by establishing a uniform orientation method that can be applied to other amniote taxa. Our results demonstrate clear differences between the trabeculae of the humerus and femur in mammals that are not seen in reptiles. Although ecological niche and postural groups have limited influence on most traditional trabecular metrics, our results highlight striking differences in trabecular orientation between these groups. Posture was correlated with trabecular orientation, probably stemming from the varied angle of limbs and the resulting directions of stress exerted during locomotion. Future research into non-primate taxa should incorporate trabecular orientation to gain a better understanding of trabecular diversity.
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