[Paleontology • 2026] Jeanerpeton mazonensis • A New, exceptionally preserved, late Carboniferous amphibamiform from the Mazon Creek Lagerstätte, Illinois, USA

 

Jeanerpeton mazonensis

Sefcovic, Kohlberg, So & Mann, 2026 

 

DOI: doi.org/10.1080/02724634.2026.2698799 

 

ABSTRACT

The Mazon Creek fossil assemblage has provided the earliest fossil records of several important early tetrapod lineages, including the oldest dissorophoid temnospondyl, Amphibamus grandiceps. Recent systematic efforts have unveiled exceptional diversity of recumbirostran tetrapods at Mazon Creek; however, similar attention has not been paid to the numerous temnospondyl fossils from the site. Here, we provide an anatomical and systematic revision to a uniquely preserved amphibamiform from Mazon Creek, FMNH PR 558, that was previously reported to have the earliest body fossil evidence of lissamphibian-like toe pads in temnospondyls. Restudy of this fossil, with particular attention devoted to the dorsal and lateral skull and the axial skeleton has revealed distinct differences from coeval and other Permo-Carboniferous amphibamiforms, allowing for the designation of the new taxon Jeanerpeton mazonensis, gen. et sp. nov. Based on preliminary observations of varying presacral vertebral counts among Mazon Creek amphibamiform fossils there is more diversity of this group from the Moscovian amongst known material than previously recognized.

Jeanerpeton mazonensis, gen. et sp. nov.

 

Allison J. Sefcovic, Payton J. Kohlberg, Calvin So and Arjan Mann. 2026. Jeanerpeton mazonensis, gen. et sp. nov.: A New, exceptionally preserved, late Carboniferous amphibamiform from the Mazon Creek Lagerstätte, Illinois. Journal of Vertebrate Paleontology. e2698799. DOI: doi.org/10.1080/02724634.2026.2698799  [24 Sep 2026]

[Paleontology • 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

 

Dinodontosaurus isiyavamanda

George, Escobar, Moody, Saanane, Day & Larkin, 2026

DOI: doi.org/10.1080/02724634.2026.2692542

Life reconstruction by Gabriel Ugueto

 

ABSTRACT 

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.

SYSTEMATIC PALEONTOLOGY

SYNAPSIDA Osborn, 1903

THERAPSIDA Broom, 1905

ANOMODONTIA Owen, 1860

DICYNODONTIA Owen, 1859

DICYNODONTOIDEA Olson, 1944

KANNEMEYERIIFORMES Maisch, 2001

DINODONTOSAURUS Romer, 1943

Diodontosaurus Tupí-Caldas, 1936 [nomen suppressum].

Chanaria Cox, 1968.

Type Species––Dinodontosaurus oliveirai Romer, 1943 (=Dicynodon tener Huene, 1935).

Diagnosis––Medium- to large-sized kannemeyeriiform (maximum skull length ca. 40 cm) with the following unique combination of character states: frontals with a “tab-like” median anterior process; postorbital bone with elongate, curved suborbital process; elongate caniniform process sharply offset from zygomatic arch; and hypertrophied tusks present in large individuals (taken from Kammerer & Ordoñez, 2021).

DINODONTOSAURUS ISIYAVAMANDA sp. nov.

Ruhuhuungualasaurus croucheri Larkin, 1994, p. 2.

Shansiodon sp. Surkov and Benton, 2004, p. 627.

Shansiodon sp. Surkov and Benton, 2008, p. 1126.

Diagnosis––Can be distinguished from both Dinodontosaurus brevirostris and Dinodontosaurus tener by a premaxillary posterior/median palatal ridge that expands anteriorly into a wide, bulbous morphology (does not retain the ridge-like morphology throughout its length), and extends further anteriorly than the point of eruption of the tusks; a midline groove extending along the temporal bar from immediately posterior to the pineal foramen to the posterior end of the postparietal; and mandibular rami that diverge more laterally. Can be further distinguished from Dinodontosaurus brevirostris by the lack of a ridge along the anterior surface of the mandibular symphysis. Can be further distinguished from Dinodontosaurus tener by a wider interorbital region and snout, and a pineal foramen that is not completely anterior to the intertemporal bar (i.e., pineal foramen is at the same anteroposterior level as the anterior portion of the bar).

Etymology––From the Manda words ‘isi ya vamanda’ that translate to ‘country of the Wamanda.’ In reference to the Wamanda people, many of whom were crucial to the discovery of the holotype, but whose individual names were not documented and never credited.

two bulky Dinodontosaurus isiyavamanda walking through dense vegetation 

Life reconstruction by Gabriel Ugueto

Hady George, Juan A. Escobar, Edmund R.R. Moody, Charles B. Saanane, Michael O. Day and 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: doi.org/10.1080/02724634.2026.2692542 [15 Sep 2026]

 

[Paleontology • 2026] Mandrasuchus milleri • A New alligatorid (Crocodylia: Alligatoridae) from the Early Paleocene (Danian) of the Denver Basin supports earliest Paleocene North American alligatorid radiation

 

Mandrasuchus milleri

Lessner, Sherman, Petermann, Panigot, Duffy & Lyson, 2026 

 

DOI: doi.org/10.1080/02724634.2026.2712566 

Illustration by Andrey Atuchin

ABSTRACT

The North American eusuchian fossil record through the Cretaceous–Paleogene (K–Pg) mass extinction shows a remarkable increase in diversity across the K–Pg boundary through the early Eocene. This is in contrast to most other vertebrate clades. Despite the group’s uninterrupted existence across the K–Pg boundary, gaps remain in the alligatorid fossil record, particularly near the K–Pg boundary and geographically in Colorado. Here we describe a new alligatorid, Mandrasuchus milleri, gen. et sp. nov., from the lower Paleocene Denver Formation of Corral Bluffs, Colorado, represented by over 15 specimens. We identify a globidontan alligatorine by the globular caudal dentition and blunted rostrum. Regardless of precise taxonomic assignment, the alligatorid is stratigraphically the earliest confirmed alligatorine, with diagnostic crania from ∼350 kyrs (Puercan 2 North American Land Mammal Age [NALMA]) and referred globular teeth from ∼200 kyrs (Puercan 1 NALMA) post-K–Pg mass extinction. The alligatorine is a new representative of a largely unresolved portion of the crocodylian phylogeny, and its addition could help resolve relationships of early diverging alligatorids and taxa historically referred to Allognathosuchus. This taxon’s distinct rostral morphology and globidont dentition suggest its ability to engage in a macrogeneralist diet. Dietary niche partitioning is likely present in this ecosystem as M. milleri lived alongside the generalist macrocarnivore Borealosuchus sternbergii, the other known Denver Formation crocodylian. The eusuchian survivorship across the K–Pg mass extinction and the morphological diversity of these apex freshwater predators underscores the degree to which freshwater terrestrial ecosystems were buffered from Earth's last mass extinction.

Mandrasuchus milleri hunting crayfish along a river bank in Colorado some 65.5 million years ago.

 Mandrasuchus milleri, gen. et sp. nov.

Emily J. Lessner, Sadie M. Sherman, Holger Petermann, Eldon Panigot, Franklin Duffy and Tyler R. Lyson. 2026. New alligatorid, Mandrasuchus milleri, from the Early Paleocene (Danian) of the Denver Basin supports earliest Paleocene North American alligatorid radiation. Journal of Vertebrate Paleontology. e2712566. DOI: doi.org/10.1080/02724634.2026.2712566 [02 Sep 2026]

[PaleoIchthyology • 2026] Nazaria limnica • A New deep bodied ray-finned fish (Osteichthyes: Actinopterygii) from the Permian Pedra do Fogo Formation (Northeastern Brazil) and its phylogenetic and paleogeographic affinities

Nazaria limnica

Richter, Cisneros, Kammerer, Pardo, Marsicano, Fröbisch, Smith & Angielczyk, 2026

 DOI: doi.org/10.1080/02724634.2026.2697805  

Artwork by Juan C. Cisneros & Martha Richter

 bsky.app/profile/cisneros.bsky.social

ABSTRACT

A deep bodied ray-finned fish is reported from Cisuralian lacustrine deposits of the Parnaíba Basin. Its ecological niche and systematic affinities are discussed, considering the paleogeographic distribution of selected Permo-Carboniferous deep bodied fishes from several separate sedimentary successions of western Gondwana. The occurrence of deep bodied fishes in the Parnaíba Basin mirrors the presence of a similarly shaped but less derived and distantly related taxon, Paranaichthys longianalis from the late Permian of the Paraná Basin of southern Brazil. The new taxon’s unique combination of characters includes an elongated pectoral fin; posteriorly inclined suspensorium; deep flank scales ornamented with fine vertical striae, tiny mandibular teeth and palatal crushing dental plates. It shares with Guildayichthys and Discoserra two preopercular bones, a supraorbital, and marginal teeth on the lower jaw. Phylogenetic analyses were performed based on two datasets. Dataset 1 included 53 characters coded for 26 deep bodied and fusiform fish fossils from Brazil, North America, China, South Africa, and Australia, with results indicating that is most closely related to the North American order Guildayichthyformes, known from marine rocks of Pennsylvanian age. Dataset 2 included 119 taxa coded for 293 characters. The two analyses place the new taxon as the sister group of a clade comprised of Blourugia and Paranaichthys. However, the results of the study of both datasets show a high degree of uncertainty about the interrelationships between the new taxon and other deep bodied Paleozoic fish species.

SYSTEMATIC PALEONTOLOGY

OSTEICHTHYES Huxley, 1880

ACTINOPTERYGII Cope, 1887

NAZARIA, gen. nov.

 

Etymology—Named after the municipality of Nazária in the State of Piauí, where the fossils were collected.

NAZARIA LIMNICA, gen. et sp. nov.

Etymology—Derives from the Greek epithet limne (‘lake’) a reference to the lacustrine paleoenvironment where the fishes lived.

Nazaria limnica, MAP PV1029 (holotype).
A, part; B, counterpart (reversed). The caudal and anal fins are not preserved in the holotype.

Abbreviations: vrs, ventral ridge scales.

Nazaria limnica, MAP PV1029 (holotype).
A, skull and anterior part of the trunk (dorsal crest not figured here); B, identification of skull bones as preserved in A and, augmented drawing of one of the anteriormost trunk scales, showing its vertical ornamental ridges and dorsal of the peg-and-socket articulation system. The hatched lines indicate uncertain bone boundaries.

Abbreviations: An, angular; a.In, anterior infraorbital; br, branchiostegal rays; Cl, cleithrum; Cla, clavicle; De, dentary; Dro, dorsal rostral; Dsp, dermosphenotic; Ent?, impression of an entopterygoid?; Ex, extrascapulars; Fr, frontal; Ju, jugal; mt, mandibular teeth; Mx, maxilla; Na, nasal; Op, operculum; Pa, parietal; Pmx-ant, premaxilla-antorbital; Pop1, preoperculum 1; Pop2, preoperculum 2; Psp, post-spiracular; Sco, scapulocoracoid; So, suborbitals; Sop, suboperculum; St, supratemporal; Su, supraorbital; Vo, vomer; VRo, ventral rostral.

 Nazaria limnica, MAP PV1029 (holotype).
A, detail of the mouth and surrounding region; B, details of the dentition.

 Abbreviations: maxt?, possible maxillary crushing teeth; mt, mandibular marginal teeth; Mx, maxilla; Vo, vomer (vomerine tooth plate).

Tentative reconstruction of the skull pattern and anteriormost flank scales of Nazaria limnica, based on MAP PV1029 (holotype), after rearrangement of some taphonomically dislocated bones (jugal, lachrymal and ventral preopercular). Short, dotted lines represent inferred bone limits (preoperculum, suboperculum, and ventral limit of the suprachleithrum). The inset features the skull sensorial line pattern.

Abbreviations: An, angular; a.In, anterior infraorbital; app, anterior process of parasphenoid; asp, posterior ascending process of parasphenoid; br, branchiostegal rays; Cl, cleithrum; Cla, clavicle; Dro, dorsal rostral; Dsp, dermosphenotic; Ent?, impression of an entopterygoid?; Ex, extrascapulars; Fr, frontal; Ju, jugal; Mx, maxilla; Na, nasal; Op, operculum; P1, pectoral fin; Pa, parietal; Par, parasphenoid; Pmx-ant, premaxilla-antorbital; Pop1, preoperculum 1; Pop2, preoperculum 2; Psp, post-spiracular; Sco, scapulocoracoid; So, suborbitals; Sop, suboperculum; sr, sclerotic ring; St, supratemporal; Su, supraorbital; Vo, vomer; Vro, ventral rostral.

Life reconstruction of Nazaria limnica, based on a composite rendering of characters observed on either the holotype, the paratype or both.

Art by Juan C. Cisneros based on Martha Richter reconstruction.

 

Martha Richter, Juan C. Cisneros, Christian F. Kammerer, Jason D. Pardo, Claudia A. Marsicano, Jörg Fröbisch, Roger M. H. Smith and Kenneth D. Angielczyk. 2026. A New deep bodied ray-finned fish (Osteichthyes/Actinopterygii) from the Permian Pedra do Fogo Formation (Northeastern Brazil) and its phylogenetic and paleogeographic affinities. Journal of Vertebrate Paleontology. e2697805. DOI: doi.org/10.1080/02724634.2026.2697805 [26 Aug 2026]

 bsky.app/profile/cisneros.bsky.social/post/3mtzp3mskp225

 bsky.app/profile/jdpardo.bsky.social/post/3mtyrzy7tw225

[Paleontology • 2026] Spea labreae • A New extinct Pleistocene Species of Spadefoot Toad (Anura: Scaphiopodidae) and comments on the Paleoecology and Paleobiogeography of Anurans from Rancho La Brea, California

Reconstruction of Spea labreae, (dark spadefoots, center) in La Brea Tar Pits compared with Spea hammondii (light spadefoot, left), the species currently present in the area, and the presence of the Mexican burrowing toad (Rhinophrynidae, bottom). 

 Cruz & Lindsey, 2026

 DOI: doi.org/10.1080/02724634.2026.2689465 

Artwork by Arturo Dávalos

ABSTRACT

Fossil amphibians hold great promise for paleoecological, paleoclimatological, and biogeographic studies because of their extreme sensitivity to environmental conditions. However, the study of fossil amphibians to date has been limited, because the fragility of frog, toad, and salamander skeletons means that diagnostic elements are rarely preserved in the fossil record. One unique locality that preserves a robust record of Quaternary amphibians is Rancho La Brea in Los Angeles, California, U.S.A. Here, we describe the amphibian fauna from the Hancock Collection of Rancho La Brea, which contains fossils from ∼45,000 years before present through the Holocene. We document previously unrecognized taxa from this locality, including the Mexican burrowing toad Rhinophrynus sp. and a new species of spadefoot toad, Spea labreae, sp. nov. Using osteological comparison material, we calculate the size of this new species of Spea, which is larger than the extant species in this genus. We analyze the current distribution and fossil record of the genus Spea and the family Rhinophrynidae, documenting changes in geographic ranges of these taxa during the Quaternary. These changes likely resulted from the interplay of deglacial climate changes and topographic complexity in the American Southwest, and may help to predict amphibian responses to climate changes impacting the region today.

Class AMPHIBIA, Linnaeus, 1767

Order ANURA Rafinesque, 1815

Family SCAPHIOPODIDAE Cope, 1865

Genus SPEA Cope, 1866

SPEA LABREAE, sp. nov.

Etymology—The specific epithet refers to La Brea, Spanish for ‘the tar’ which gave rise to the name of Rancho La Brea, the locality where this species is found.

 

Locality, Horizon, and Age—Pit A, Rancho La Brea, Los Angeles, California, Late Pleistocene–Holocene.

 

Reconstruction of Spea labreae, (dark spadefoots, center and right) in La Brea Tar Pits compared with Spea hammondii (light spadefoot, left), the species currently present in the area, and the presence of the Mexican burrowing toad (Rhinophrynidae, bottom).

 Artwork by Arturo Dávalos.

 

J. Alberto Cruz and Emily L. Lindsey. 2026. A New extinct Pleistocene Species of Spadefoot Toad and comments on the Paleoecology and Paleobiogeography of Anurans from Rancho La Brea, California. Journal of Vertebrate Paleontology. e2689465. DOI: doi.org/10.1080/02724634.2026.2689465 [04 Aug 2026]

[Paleontology • 2026] Kank australis • New unenlagiid (Theropoda: Unenlagiidae) from the Chorrillo Formation (Late Cretaceous, Maastrichtian), SW Patagonia, Argentina

 

Kank australis

Motta, Rolando, Rozadilla, Agnolín, Egli, Herrera, Chimento, Coco, Tsuihiji, Manabe, Pol & Novas, 2026

 

DOI: doi.org/10.1080/02724634.2026.2656456 

A reconstruction by Gabriel Díaz Yantén

 

ABSTRACT

Unenlagiids constitute a group of paravian theropods up to now represented in Gondwanan landmasses. They are particularly diverse in northern Patagonia, where at least seven species were discovered in Upper Cretaceous beds. In southern Patagonia, by contrast, the record is restricted to a few isolated remains of indeterminate taxa from Argentina and Chile. The aim of the present contribution is to describe an unenlagiid, Kank australis gen. et sp. nov. from the Maastrichtian beds of southern Santa Cruz, southern Patagonia, Argentina. Kank australis is represented by vertebrae, isolated pedal phalanges, and shed teeth. The holotype individual has a unique combination of characters, including a highly pneumatized cervical vertebra with well-developed parapophysis and carotid processes. Further, a pedal phalanx II-2 resembles those of troodontids due the reduction of the distal condyles, and differs from other known unenlagiids. The apomorphic condition of the few available elements suggests that Kank australis was probably distinct from its kin and reinforces the hypothesis that Unenlagiidae was a morphologically disparate clade.

SYSTEMATIC PALEONTOLOGY

DINOSAURIA OWEN, 1842

SAURICHIA SEELEY, 1888

THEROPODA MARSH, 1881

PARAVES SERENO, 1997

UNENLAGIIDAE (Bonaparte, 1999)

KANK AUSTRALIS gen. et sp. nov.

Diagnosis—Medium-sized unenlagiid (phalanges similar in size to Neuquenraptor argentinus estimated in ∼27 kg; Motta, 2023) showing the following combination of characters (autapomorphies marked by an asterisk): (1) dentary teeth having mesial carinae restricted to the apical third of the crown (shared with Austroraptor); (2) labiolingually compressed maxillary teeth “8” in cross-section (shared with Buitreraptor); (3) dentary teeth having a crenulate mesial carina restricted to its apical third; (4) cervicodorsal vertebra having three pneumatic foramina on its ventral surface*; (5) cervicodorsal vertebra having epipophyseal fossa*; and (6) phalanx 2-II showing reduced distal condyles and collateral pits located very close to the anterodorsal corner of the condyles (shared with troodontids).

Etymology—“Kank,” in reference to the “elder Rhea,” who created the constellation Choiols (Southern Cross constellation) in the Aonikenk mythology, and “australis,” which means “from south” in Latin, in reference to the southern latitude where this dinosaur was found.

 

Matías J. Motta, Alexis M. Aranciaga Rolando, Sebastián Rozadilla, Federico L. Agnolín, Federico Brissón Egli, Gerardo P. Álvarez Herrera, Nicolás R. Chimento, Gastón Lo Coco, Takanobu Tsuihiji, Makoto Manabe, Diego Pol and Fernando E. Novas. 2026. New unenlagiid from the Chorrillo Formation (Late Cretaceous, Maastrichtian), SW Patagonia, Argentina. Journal of Vertebrate Paleontology. e2656456. DOI: doi.org/10.1080/02724634.2026.2656456  [28 May 2026]

https://newsroom.taylorandfrancisgroup.com/heron-like-fish-eating-dinosaur-from-70-million-years-ago-discovered-in-argentina

https://www.macnconicet.gob.ar/kank-australis-el-nuevo-raptor-descubierto-en-la-patagonia-argentina

[Paleontology • 2026] Labrujasuchus expectatus • A New shuvosaurid (Archosauria: Poposauroidea) from the Late Triassic (Norian) Hayden Quarry of New Mexico, U.S.A.

Labrujasuchus expectatus

Turner, Kernan, Laing, Pritchard, Stocker, Irmis, Smith, Werning & Nesbitt, 2026

DOI: doi.org/10.1080/02724634.2026.2618182

Artwork: Jorge Gonzalez/NHMLAC Dinosaur Institute

ABSTRACT

Bipedal shuvosaurid archosaurs were present for much of the Late Triassic Period. The clade is particularly diverse in Upper Triassic assemblages in the western U.S.A. Isolated bones are easily differentiated from contemporary archosaurs, but the two named North American species, Shuvosaurus inexpectatus and Effigia okeeffeae, display remarkably similar skeletons. Here we describe a new shuvosaurid species, Labrujasuchus expectatus, gen. et sp. nov., from the middle Norian (∼212 Ma) Hayden Quarry of northern New Mexico, U.S.A., located within the Petrified Forest Member of the Chinle Formation, that fills the temporal gap between the two species. The holotype consists of a partial skeleton, with additional shuvosaurid material from the Hayden Quarry likely pertaining to this taxon. This taxon is distinguished by four autapomorphies and assignable to Shuvosauridae based on a deep fossa present on the posterodorsal edge of the coracoid, the proximal portion of the humerus less than twice the width of the midshaft, the anteromedial tuber of the femur large and ‘hooked’ posteriorly, and a ventrally descended posterolateral portion of the femoral head. Recent Bayesian estimates of archosaur phylogeny and divergence times suggested a Middle Triassic split for Shuvosauridae as well as a decrease in the rate of morphological evolution for the clade relative to that of other archosaurs. The anatomical similarity of L. expectatus with other shuvosaurids is consistent with these estimated low rates, and the long gaps in the fossil record for the clade suggest that much of their evolutionary history remains to be sampled.

Reconstruction of Labrujasuchus expectatus, a new species of Shuvosauridae from Late Triassic rocks of Ghost Ranch, New Mexico.

Artwork: Jorge Gonzalez/NHMLAC Dinosaur Institute

SYSTEMATIC PALEONTOLOGY

ARCHOSAURIA Cope, 1870 (sensu Gauthier & Padian, 1985)

SUCHIA Krebs, 1974 (sensu Benton & Clark 1988)

SHUVOSAURIDAE Chatterjee, 1993 (sensu Nesbitt, 2011)

LABRUJASUCHUS gen. nov.

Type Species—Labrujasuchus expectatus

Etymology—The generic name Labrujasuchus (“la-broo-ha-soo-kus”) is derived from “Ranchos de los Brujos,” Ranch of the Witches, an old Spanish name for the Ghost Ranch area, and the Greek word Σοῦχος (suchus) meaning “crocodile.” It is masculine in gender.

 

LABRUJASUCHUS EXPECTATUS sp. nov.

Etymology—From the Latin “expectatus” for expected or awaited.

The species name is based on the anticipated nature of a shuvosaurid discovery at the Hayden Quarry.

Alan H. Turner, Ciara E. Kernan, Adam Laing, Adam C. Pritchard, Michelle R. Stocker, Randall B. Irmis, Nathan D. Smith, Sarah Werning and Sterling J. Nesbitt. 2026. A New shuvosaurid (Archosauria, Poposauroidea) from the Late Triassic (Norian) Hayden Quarry of New Mexico, U.S.A. Journal of Vertebrate Paleontology.  e2618182 DOI: doi.org/10.1080/02724634.2026.2618182  [26 May 2026]

[Paleontology • 2026] Acutodon villeveyracensis • A New pan-shinisaur Lizard (Anguimorpha) from the lower Campanian of Villeveyrac (Hérault, France)

Acutodon villeveyracensis 

Jansen, Augé, Garcia, Otero & Valentin, 2026

DOI: doi.org/10.1080/02724634.2026.2636649 

Artwork by Olivier Jansen

ABSTRACT

The Chinese crocodile lizard (Anguimorpha, Pan-Shinisaurus Shinisaurus crocodilurus) is an endangered species inhabiting the lowland rainforests of southeastern China and northern Vietnam. The evolutionary history of this clade remains poorly understood, as only five fossil species and a few fossil specimens are described from the Lower Cretaceous of China and the Cenozoic of Europe and North America, revealing a considerable gap in the fossil record. A new anguimorph, Acutodon villeveyracensis gen. et sp. nov., is described from the lower Campanian (Upper Cretaceous) locality of Villeveyrac (Hérault, France), corresponding to a freshwater subtropical paleoenvironment. The species is attributed to a pan-shinisaur anguimorph based on a toothed maxilla sharing multiple characters with the extant Sh. crocodilurus and its fossil relatives, notably tall, tapered, and recurved teeth, with mesiodistally constricted tooth bases lacking basal infoldings but possessing medial resorption pits, and a posteromedially shifted anterior superior alveolar foramen. This Cretaceous record is the oldest in Europe for pan-shinisaur lizards. It pre-dates the occurrence of this clade in Europe by around 30 Myr, raising questions about the paleobiogeographic history of pan-shinisaur lizards.

Acutodon villeveyracensis holotype and unique material (UP.VIL.2010.55). Photographs, virtual reconstruction, and interpretative drawings of the maxilla in A, labial; B, lingual; C, occlusal; and D, dorsal views. Note that the posteriormost tooth was lost after CT scanning.

Abbreviations: asaf, anterior superior alveolar foramen; ce, cutting edge; cl, crista lateralis; ct, crista transversalis; fp, facial process; lf, labial foramina; lic, lamina intercristalis; lpp, lateral premaxillary process; lr, lacrimal recess; mpp, medial premaxillary process; ps, palatal shelf; rp, resorption pit; sds, supradental shelf. Scale bar equals 10 mm.

Details of the teeth of Acutodon villeveyracensis holotype and unique material (UP.VIL.2010.55) from the virtual reconstruction.
A, morphology in anterior view; B, section in median plane; C, section in horizontal plane.

Abbreviations: asaf, anterior superior alveolar foramen; c, cement; cl, crista lateralis; ct, crista transversalis; d, dentine; lf, labial foramen; lpp, lateral premaxillary process; m, maxilla; mpp, medial premaxillary process; ps, palatal shelf; t1–t4, teeth numbered from front to back. Scale bar equals 2 mm.

SQUAMATA Oppel, 1811

ANGUIMORPHA Fürbringer, 1900

PAN-SHINISAURUS sensu Smith and Gauthier, 2013

ACUTODON gen. nov.

ACUTODON VILLEVEYRACENSIS, gen. et sp. nov.

Diagnosis—Large anguimorph lizard characterized by the following combination of characters: the teeth are tall, thin, and possess a tapered apex; anterior teeth are strongly posteriorly recurved, but the most posterior teeth are straight; the teeth lack striations and basal infoldings; the base of the teeth expands lingually but is strongly anteroposteriorly compressed, and is covered in a thin layer of cementum; the crowns have a faint cutting edge, restricted to the most apical portion; medial resorption pits are ...

Etymology—‘acutus’ (Latin), sharp, pointed, piercing, and thin; ‘ὀδόντος’ (Greek), teeth; the genus name refers to the tapered, sharp, and thin teeth of this new genus; ‘villeveyracensis’ (Latin) from the locality of Villeveyrac, department of Hérault, France, where this new lizard taxon has been found.

Acutodon villeveyracensis
Paleoartistic reconstruction of the new genus and species of pan-shinisaur lizard from the lower Campanian of Villeveyrac (Hérault, France). Original artwork by Olivier Jansen.

Olivier Jansen, Marc Augé, Geraldine Garcia, Olga Otero and Xavier Valentin. 2026. A New pan-shinisaur Lizard (Anguimorpha) from the lower Campanian of Villeveyrac (Hérault, France). Journal of Vertebrate Paleontology. DOI: doi.org/10.1080/02724634.2026.2636649  [20 May 2026]

[PaleoMammalogy • 2026] Cimolodon desosai • Cranial and Postcranial Remains of A New Species of Cimolodon (Multituberculata: Cimolodontidae) from the Upper Cretaceous (Campanian) El Gallo Formation of Baja California, México

Cimolodon desosai

Mantilla, Newbins, Fastovsky, Zhang, Montellano-Ballesteros, Alcántara & Chen, 2026

DOI: doi.org/10.1080/02724634.2026.2641109

Illustration by Andrey Atuchin

ABSTRACT

Late Cretaceous mammals from North America are predominantly known from isolated teeth and fragmentary jaws and from localities representing coastal lowlands along the Western Interior Seaway. Here, we report craniodental and associated postcranial remains of a new species of the cimolodontid multituberculate genus Cimolodon from the Upper Cretaceous (Campanian) El Gallo Formation of Baja California, México. The specimen was deposited along the Pacific Coast between 75.17 ± 0.30 Ma and 74.55 ± 0.18 Ma. It represents the most complete mammal known from the Mesozoic of México and one of the best known cimolodontan multituberculates from North America. Morphologically, the new species, Cimolodon desosai, is most like C. nitidus, but differences include upper anterior premolar shape, molar cusp formulae, and relative length proportions of the cheek teeth. Phylogenetic analysis supports placement of the new species within Cimolodon and Ptilodontoidea, but uncertainties remain regarding relationships among cimolodontan families. Using the craniodental and postcranial data, we quantitatively reconstruct C. desosai as a small-bodied (∼100 g), animal-dominated omnivore with a scansorial locomotor mode. With the new taxonomic occurrence, the El Gallo mammalian local fauna is now known from 16 specimens referred to three multituberculate species (Mesodma cf. M. formosa, ?Stygimys sp., and Cimolodon desosai), one metatherian (Pediomys sp.), and one eutherian (Gallolestes pachymandibularis). Although further sampling is needed, the mammalian local fauna presently shows greatest biogeographic affinities with the Terlingua local fauna of western Texas.

SYSTEMATIC PALEONTOLOGY

MAMMALIA Linnaeus, 1758

MULTITUBERCULATA Cope, 1884

CIMOLODONTA McKenna, 1975

PTILODONTOIDEA Sloan and Van Valen, 1965

CIMOLODONTIDAE McKenna, 1975

CIMOLODON Marsh, 1889

CIMOLODON DESOSAI, sp. nov.

Partial cranium of the holotype of Cimolodon desosai (IGM 14691).
Images are three-dimensional surface renderings from μCT scans in: A, anterior; B, stereo dorsal; C, stereo ventral; D, left lateral; and E, right lateral views of the partial cranium; and F, occlusal view of the right upper cheek tooth row in high magnification. Dashed white lines represent interpreted position of cranial bone sutures.

Abbreviations: al, anterior lamina; fr, frontal; iof, intraorbital foramen; mx, maxilla; na, nasal; naf, nasal foramen; otc, orbitotemporal canal; pa, parietal; pav, palatal vacuity; pmx, premaxilla; pop, postorbital process; sq, squamosal; zpm, zygomatic process of the maxilla. Scale bar equals 10 mm for A–E and 2 mm for F.

Cimolodon desosai on the tree with a fruit in its mouth. It was about the size of a golden hamster. It likely scampered on the ground and in the trees and ate fruits and insects.

Illustration by Andrey Atuchin

 

 

Gregory P. Wilson Mantilla, Isiah R. Newbins, David E. Fastovsky, Yue Zhang, Marisol Montellano-Ballesteros, Dalia García Alcántara and Meng Chen. 2026. Cranial and Postcranial Remains of A New Species of Cimolodon (Mammalia, Multituberculata, Cimolodontidae) from the Upper Cretaceous (Campanian) El Gallo Formation of Baja California, México. Journal of Vertebrate Paleontology. e2641109. DOI: doi.org/10.1080/02724634.2026.2641109  [22 Apr 2026]

[Paleontology • 2026] Sonselasuchus cedrus • Osteology and Relationships of A New shuvosaurid (Pseudosuchia: Poposauroidea: Shuvosauridae) from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona, U.S.A

Sonselasuchus cedrus

Smith & Sidor, 2026

DOI: doi.org/10.1080/02724634.2025.2604859

Artwork by Gabriel Ugueto

ABSTRACT

Shuvosauridae is a clade of pseudosuchian archosaurs currently represented by three named species characterized by a body plan strikingly convergent with that of ornithomimid theropod dinosaurs. This paper documents a new genus and species of shuvosaurid from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona. Sonselasuchus cedrus, gen. et sp. nov., is largely diagnosed by features of the maxilla, including a reduced body and anterior process, an enlarged subnarial foramen, and an expanded facet on the posterior process, although other unique cranial features are also noted herein. By contrast, its postcranial anatomy is largely similar to what has been described for other shuvosaurids, although subtle differences are noted. A phylogenetic analysis finds S. cedrus in an unresolved clade with Effigia okeeffeae and Shuvosaurus inexpectatus, likely as a result of non-overlapping missing data, particularly for the skull of Shuvosaurus. A review of the shuvosaurid fossil record indicates that shuvosaurids were persistent components of Late Triassic terrestrial vertebrate faunas in North America. S. cedrus is represented by a minimum number of 36 individuals, mostly skeletally immature, that occur within a multitaxic bonebed of almost exclusively disarticulated elements. An analysis of the relative size change of limb dimensions indicates the forelimb was growing on a negative allometric trajectory relative to the hindlimb, which is consistent with a transition in locomotory mode from quadrupedal to bipedal in S. cedrus during ontogeny.

Life restoration of Sonselasuchus cedrus as depicted by Gabriel Ugueto. Note the occurrence of individuals in both bipedal and quadrupedal stances.

SYSTEMATIC PALEONTOLOGY

ARCHOSAURIA Cope, 1869

PSEUDOSUCHIA Zittel, 1887–1890

PARACROCODYLOMORPHA Parrish, 1993

POPOSAUROIDEA Nopcsa, 1923

SHUVOSAURIDAE Chatterjee, 1993

SONSELASUCHUS CEDRUS gen. et sp. nov.

Etymology—For the genus, ‘Sonsela’ refers to the Sonsela Member of the Chinle Formation, the type section is located at the Sonsela Buttes on the Navajo Nation; ‘suchus’ is a Latinization of the Greek word soukhos, for the Egyptian crocodile deity Sobek, reflecting the pseudosuchian affinities of the taxon. The specific epithet, ‘cedrus’ is the genus name for the common cedar (actually the juniper, Juniperus spp.) and refers to Cedar Tank, the geographic feature in Petrified Forest National Park near the type locality.

Holotype—PEFO 47305/UWBM 119436, left maxilla.

Locality and Horizon—The Kaye Quarry (PFV 410/UWBM C2226) is located west of Cedar Tank at Petrified Forest National Park, Apache County, Arizona, U.S.A. (Fig. 1). The site is within the Jim Camp Wash beds of the Sonsela Member of the Chinle Formation and is Norian in age (Marsh et al., 2024). ...

Elliott Armour Smith and Christian A. Sidor. 2026. Osteology and Relationships of A New shuvosaurid (Pseudosuchia, Poposauroidea) from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona, U.S.A. Journal of Vertebrate Paleontology. e2604859. DOI: doi.org/10.1080/02724634.2025.2604859 [08 Mar 2026]

[Paleontology • 2026] The ontogenetically youngest known pachycephalosaur (Dinosauria: Ornithischia) postcranium

 

juvenile Pachycephalosauria indet. (CMNFV 22039)
Life reconstruction in an environment typical of the upper Maastrichtian Frenchman Formation, Saskatchewan. 

in Moore, Evans, Ryan, Patterson et Mallon, 2026. 

  DOI: doi.org/10.1080/02724634.2026.2616325

Illustration by Kaitlin Lindblad. 

 x.com/Jordan_Mallon

 

ABSTRACT

Pachycephalosaurian dinosaurs are represented in the fossil record primarily by their taphonomically resistant frontoparietal domes that developed fully only at maturity. Consequently, the postcranial record of Pachycephalosauria is poor, particularly for immature forms. Here, we describe the ontogenetically youngest known, and Canada’s second-most complete, pachycephalosaur postcranium, collected from the uppermost Maastrichtian Frenchman Formation, Saskatchewan. Despite its small size (estimated total length ∼90 cm), the skeleton shows several characters diagnostic of Pachycephalosauria, including a double ridge-and-groove articulation on the pre- and postzygapophyses of the dorsal neural arches, a medial flange on the postacetabular process of the ilium, and a highly reduced pubis that contributes only minimally to the acetabular margin. Histological sectioning of the crural bones shows an immature woven bone texture. The absence of cyclical or annual growth indicators suggests that this specimen was less than a year old at the time of death. Phylogenetic analysis recovers the specimen as a member of Pachycephalosaurinae, perhaps related to Prenocephale, but the lack of cranial data for our specimen and the complementary lack of postcranial data for other pachycephalosaurs make this determination tenuous. Spatiotemporal considerations suggest a possible but currently untestable affiliation with Sphaerotholus buchholtzae. The relatively long hindlimbs of the juvenile compared with those of adult pachycephalosaurs indicate probable negative ontogenetic allometry in the hindlimbs.

 Preserved elements (in red) of juvenile Pachycephalosauria indet. (CMNFV 22039).
 The preserved left ischium does not show in this view. Diagram illustrates preserved elements only and does not accurately reflect the proportions of CMNFV 22039.

Skeletal drawing modified after original illustrations of Pachycephalosaurus (postcranium) and “Dracorex” (cranium) by Gregory Paul. Used with permission.

Life reconstruction of CMNFV 22039 in an environment typical of the upper Maastrichtian Frenchman Formation. 

Illustration by Kaitlin Lindblad. Used with permission.

 

Bryan R. S. Moore, David C. Evans, Michael J. Ryan, R. Timothy Patterson and Jordan C. Mallon. 2026. The ontogenetically youngest known pachycephalosaur (Dinosauria: Ornithischia) postcranium. Journal of Vertebrate Paleontology. e2616325. DOI: 10.1080/02724634.2026.2616325 [26 Feb 2026]

 www.tandfonline.com/doi/full/10.1080/02724634.2026.2616325

 x.com/Jordan_Mallon/status/2027031604879835644