Dinodontosaurus isiyavamanda, new dicynodont from Triassic of Tanzania + turtle systematics + Sclerocephalus (Permian temnospondyl) lower jaw ossification (free pdfs)
68 views
Skip to first unread message
Ben Creisler
Sep 16, 2026, 11:11:43 AM (7 days ago) Sep 16
to DinosaurMa...@googlegroups.com
Ben Creisler
New tetrapod papers:
Dinodontosaurus isiyavamanda sp. nov.
Hady George , Juan A. Escobar , Edmund R.R. Moody , Charles B. Saanane , Michael O. Day & Nigel R. Larkin (2026)
Craniomandibular osteology of Dinodontosaurus isiyavamanda sp. nov. (Therapsida: Anomodontia) from the Manda Beds of Tanzania and new support for a younger age for the alleged oldest dinosaurs
Journal of Vertebrate Paleontology e2692542
doi: https://doi.org/10.1080/02724634.2026.2692542
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2692542
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2026.2692542
Fossils from the Manda Beds of Tanzania have greatly informed on the diversity and evolution of Triassic tetrapods, including on what might be the oldest dinosaurs. Here, a new dicynodont taxon from the Manda Beds is described. It lacks key anatomical traits of known dicynodonts from the Manda Beds, as well as the Sino-African genus Shansiodon to which some of this material was previously referred. The new taxon is referred to the otherwise South American Dinodontosaurus based on the diagnostic presence of frontals with “tab-like” anterior processes and a combination of other traits seen in the genus. This Tanzanian material possesses a predominantly bulbous posterior/median palatal ridge of the premaxilla and a midline groove along the temporal bar, among other traits that are absent in the South American Dinodontosaurus material, indicating it represents a distinct species, here named Dinodontosaurus isiyavamanda sp. nov. Phylogenetic analyses conducted with Bayesian estimation and parsimony support the inclusion of this species in Dinodontosaurus. The unique palate of D. isiyavamanda is hypothesized to be related to resource partitioning, representing different adaptations for food processing than coeval dicynodonts. The presence of Dinodontosaurus suggests the mid-to-upper Lifua Member of the Manda Beds is equivalent to the Dinodontosaurus Assemblage Zone of Brazil and the Chañares Formation of Argentina. Consequently, the mid-to-upper Lifua Member, which includes what are possibly the oldest records of dinosaurs globally, can be confidently interpreted as late Ladinian to Carnian in age, supporting recent research questioning its equivalency with the Cynognathus Assemblage Zone of South Africa.
====
Free pdf:
Serjoscha W. Evers & Walter G. Joyce (2026)
Transforming turtle systematics: challenges, opportunities and the path ahead
Journal of Systematic Palaeontology 24(2): 2707291
doi: https://doi.org/10.1080/14772019.2026.2707291
https://www.tandfonline.com/doi/full/10.1080/14772019.2026.2707291
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/14772019.2026.2707291
Turtle systematics has a long history at the interface of palaeontology and phylogenetic methodology, supported by a rich fossil record, abundant extant comparative material, and a broadly stable molecular framework for relationships among living clades. Here we review the state of the art in turtle systematics and identify key outstanding problems that continue to limit phylogenetic resolution and macroevolutionary inference. These include the phylogenetic position of the turtle total group among amniotes and the placement of critical early stem taxa; the unclear divergence of crown turtles amid multiple Mesozoic clades of uncertain affinities; the cryptic or missing stem lineages of major crown clades and pronounced asymmetries in fossil representation among sister lineages; unresolved relationships surrounding the origins and early evolution of marine turtles; major post-Eocene knowledge gaps driven by collection bias; and persistent uncertainty regarding rates, modes, and drivers of morphological evolution across deep time. We argue that the next advances in turtle systematics will depend on strengthening the anatomical data pipeline through high-resolution imaging and consistent open-data practices, modernizing inference through wider adoption of Bayesian, total-evidence and time-calibrated phylogenetic frameworks, and increasing integration among museum revision, targeted fieldwork and interdisciplinary collaboration. Together, these steps provide a realistic roadmap for transforming turtle systematics into a more rigorous and broadly influential model system for vertebrate evolution.
Dorota Konietzko-Meier & Nicole Klein (2026)
Diverse ossification pathways in the lower jaw of Sclerocephalus (Lower Permian) as revealed by the first record of chondroid bone in Amphibia
Scientific Reports 16: 28764
doi: https://doi.org/10.1038/s41598-026-68964-y
https://link.springer.com/article/10.1038/s41598-026-68964-y
Free pdf:
Dinodontosaurus isiyavamanda sp. nov.
Hady George , Juan A. Escobar , Edmund R.R. Moody , Charles B. Saanane , Michael O. Day & Nigel R. Larkin (2026)
Craniomandibular osteology of Dinodontosaurus isiyavamanda sp. nov. (Therapsida: Anomodontia) from the Manda Beds of Tanzania and new support for a younger age for the alleged oldest dinosaurs
Journal of Vertebrate Paleontology e2692542
doi: https://doi.org/10.1080/02724634.2026.2692542
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2692542
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/02724634.2026.2692542
Fossils from the Manda Beds of Tanzania have greatly informed on the diversity and evolution of Triassic tetrapods, including on what might be the oldest dinosaurs. Here, a new dicynodont taxon from the Manda Beds is described. It lacks key anatomical traits of known dicynodonts from the Manda Beds, as well as the Sino-African genus Shansiodon to which some of this material was previously referred. The new taxon is referred to the otherwise South American Dinodontosaurus based on the diagnostic presence of frontals with “tab-like” anterior processes and a combination of other traits seen in the genus. This Tanzanian material possesses a predominantly bulbous posterior/median palatal ridge of the premaxilla and a midline groove along the temporal bar, among other traits that are absent in the South American Dinodontosaurus material, indicating it represents a distinct species, here named Dinodontosaurus isiyavamanda sp. nov. Phylogenetic analyses conducted with Bayesian estimation and parsimony support the inclusion of this species in Dinodontosaurus. The unique palate of D. isiyavamanda is hypothesized to be related to resource partitioning, representing different adaptations for food processing than coeval dicynodonts. The presence of Dinodontosaurus suggests the mid-to-upper Lifua Member of the Manda Beds is equivalent to the Dinodontosaurus Assemblage Zone of Brazil and the Chañares Formation of Argentina. Consequently, the mid-to-upper Lifua Member, which includes what are possibly the oldest records of dinosaurs globally, can be confidently interpreted as late Ladinian to Carnian in age, supporting recent research questioning its equivalency with the Cynognathus Assemblage Zone of South Africa.
====
Free pdf:
Serjoscha W. Evers & Walter G. Joyce (2026)
Transforming turtle systematics: challenges, opportunities and the path ahead
Journal of Systematic Palaeontology 24(2): 2707291
doi: https://doi.org/10.1080/14772019.2026.2707291
https://www.tandfonline.com/doi/full/10.1080/14772019.2026.2707291
Free pdf:
https://www.tandfonline.com/doi/epdf/10.1080/14772019.2026.2707291
Turtle systematics has a long history at the interface of palaeontology and phylogenetic methodology, supported by a rich fossil record, abundant extant comparative material, and a broadly stable molecular framework for relationships among living clades. Here we review the state of the art in turtle systematics and identify key outstanding problems that continue to limit phylogenetic resolution and macroevolutionary inference. These include the phylogenetic position of the turtle total group among amniotes and the placement of critical early stem taxa; the unclear divergence of crown turtles amid multiple Mesozoic clades of uncertain affinities; the cryptic or missing stem lineages of major crown clades and pronounced asymmetries in fossil representation among sister lineages; unresolved relationships surrounding the origins and early evolution of marine turtles; major post-Eocene knowledge gaps driven by collection bias; and persistent uncertainty regarding rates, modes, and drivers of morphological evolution across deep time. We argue that the next advances in turtle systematics will depend on strengthening the anatomical data pipeline through high-resolution imaging and consistent open-data practices, modernizing inference through wider adoption of Bayesian, total-evidence and time-calibrated phylogenetic frameworks, and increasing integration among museum revision, targeted fieldwork and interdisciplinary collaboration. Together, these steps provide a realistic roadmap for transforming turtle systematics into a more rigorous and broadly influential model system for vertebrate evolution.
====
Free pdf:
Dorota Konietzko-Meier & Nicole Klein (2026)
Diverse ossification pathways in the lower jaw of Sclerocephalus (Lower Permian) as revealed by the first record of chondroid bone in Amphibia
Scientific Reports 16: 28764
doi: https://doi.org/10.1038/s41598-026-68964-y
https://link.springer.com/article/10.1038/s41598-026-68964-y
https://www.nature.com/articles/s41598-026-68964-y
Dermal bones are typically thought to form directly from mesenchyme, however some can develop via a transient tissue called chondroid bone, which are well documented among fishes and amniotes. Here, we report the first occurrence of chondroid bone among non-amniote tetrapods and the stratigraphically oldest record of this tissue among vertebrates, in the temnospondyl Sclerocephalus nobilis from the Lower Permian of Germany. Histological analysis of its mandible reveals a heterogeneity of developmental pathways: the angular forms through direct intramembranous ossification, the articular ossifies endochondrally from Meckelian cartilage, and the dermal surangular uniquely contains chondroid bone, with chondrocyte-like cells embedded in the matrix composed of interwoven loop complexes. This tissue likely represents an early developmental stage, promoting rapid expansion of the bone surface while potentially providing mechanical support in regions experiencing high stress during feeding. The angular exhibits a diploë structure and is composed of lamellar and parallel-fibred bone, with remnants of avascular faint parallel-fibred bone representing the larval stage. The articular represents the only endochondral bone and consists of an early-formed periosteal bone that is parallel-fibred in nature, with prominent Sharpey’s fibers and a secondary trabecular endosteal region. The discovery of chondroid bone in Sclerocephalus expands the known diversity of skeletal tissues among early tetrapods and suggests that transitional bone types may have been more widespread than previously recognized, but are likely underreported due to preservational biases and limited sampling.
Dermal bones are typically thought to form directly from mesenchyme, however some can develop via a transient tissue called chondroid bone, which are well documented among fishes and amniotes. Here, we report the first occurrence of chondroid bone among non-amniote tetrapods and the stratigraphically oldest record of this tissue among vertebrates, in the temnospondyl Sclerocephalus nobilis from the Lower Permian of Germany. Histological analysis of its mandible reveals a heterogeneity of developmental pathways: the angular forms through direct intramembranous ossification, the articular ossifies endochondrally from Meckelian cartilage, and the dermal surangular uniquely contains chondroid bone, with chondrocyte-like cells embedded in the matrix composed of interwoven loop complexes. This tissue likely represents an early developmental stage, promoting rapid expansion of the bone surface while potentially providing mechanical support in regions experiencing high stress during feeding. The angular exhibits a diploë structure and is composed of lamellar and parallel-fibred bone, with remnants of avascular faint parallel-fibred bone representing the larval stage. The articular represents the only endochondral bone and consists of an early-formed periosteal bone that is parallel-fibred in nature, with prominent Sharpey’s fibers and a secondary trabecular endosteal region. The discovery of chondroid bone in Sclerocephalus expands the known diversity of skeletal tissues among early tetrapods and suggests that transitional bone types may have been more widespread than previously recognized, but are likely underreported due to preservational biases and limited sampling.
===
Reply all
Reply to author
Forward
0 new messages