[Paleontology • 2025] Thilastikosuchus scutorectangularis • A New notosuchian (Crocodyliformes: Mesoeucrocodylia) from the Quiricó Formation, Lower Cretaceous, Sanfranciscana Basin, Brazil

Thilastikosuchus scutorectangularis

 de Carvalho, Santos, Pinto & Santucci, 2025 

DOI: doi.org/10.1080/02724634.2025.2452947 

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ABSTRACT

Notosuchians comprise a clade of mostly terrestrial crocodyliforms generally found in Cretaceous Gondwanan deposits. They evolved into many forms and some species show convergences with mammalian features such as the development of a high degree of heterodonty and multicuspid teeth. South American deposits concentrate the highest number of described notosuchian species, which is more than twice the number of taxa known from strata elsewhere. Here, a novel candidodontid notosuchian, Thilastikosuchus scutorectangularis, gen. et sp. nov., is presented and described, comprising a new monospecific genus and the oldest notosuchian record found in Brazil, and likely from South America. This new taxon lacks the sharp hypertrophied caniniform teeth of closely related forms, such as Malawisuchus and Pakasuchus, but shares the posterior molariform teeth with increasingly wider crowns and denticulated cingula. Additionally, the phylogenetic analysis with the inclusion of the new Brazilian material places Candidodontidae as the earliest notosuchian radiation, shedding new light into its origins.

Thilastikosuchus scutorectangularis, gen. et sp. nov.

Thilastikosuchus scutorectangularis gen. et sp. nov.

reconstruction by Felipe Elias

Joyce Celerino de Carvalho, Daniel Martins dos Santos, Ricardo Lourenço Pinto and Rodrigo Miloni Santucci. 2025. Anatomical Description and Systematics of A New notosuchian (Mesoeucrocodylia; Crocodyliformes) from the Quiricó Formation, Lower Cretaceous, Sanfranciscana Basin, Brazil. Journal of Vertebrate Paleontology. e2452947. DOI: doi.org/10.1080/02724634.2025.2452947  

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[Paleontology • 2024] Benggwigwishingasuchus eremicarminis • A New pseudosuchian (Archosauria: Pseudosuchia) from the Favret Formation of Nevada reveals that Archosauriforms occupied Coastal Regions globally during the Middle Triassic

Benggwigwishingasuchus eremicarminis 

Smith, Klein, Sander & Schmitz, 2024 

DOI: 10.1098/rsbl.2024.0136

Abstract

Recent studies suggest that both stem- and crown-group Archosauria encompassed high ecological diversity during their initial Triassic radiation. We describe a new pseudosuchian archosaur, Benggwigwishingasuchus eremicarminis gen. et sp. nov., from the Anisian (Middle Triassic) Fossil Hill Member of the Favret Formation (Nevada, USA), a pelagic setting in the eastern Panthalassan Ocean characterized by the presence of abundant ammonoids and large-bodied ichthyosaurs. Coupled with archosauriforms from the eastern and western Tethys Ocean, Benggwigwishingasuchus reveals that pseudosuchians were also components of Panthalassan ocean coastal settings, establishing that the group occupied these habitats globally during the Middle Triassic. However, Benggwigwishingasuchus, Qianosuchus, and Ticinosuchus (two other pseudosuchians known from marine sediments) are not recovered in a monophyletic group, demonstrating that a nearshore marine lifestyle occurred widely across Archosauriformes during this time. Benggwigwishingasuchus is recovered as part of an expanded Poposauroidea, including several taxa (e.g. Mandasuchus, Mambawakalae) from the Middle Triassic Manda Beds of Tanzania among its basally branching members. This implies a greater undiscovered diversity of poposauroids during the Early Triassic, and supports that the group, and pseudosuchians more broadly, diversified rapidly following the End-Permian mass extinction.

Class Reptilia Linnaeus, 1758

Archosauriformes  

Archosauria  

Pseudosuchia  

Poposauroidea  

Benggwigwishingasuchus eremicarminis gen. et sp. nov.
Holotype skeleton (LACM-DI 158616) (a) (pelvis block mirrored for articulation); and interpretive drawing (b)  

Genus Benggwigwishingasuchus

Benggwigwishingasuchus eremicarminis gen. et sp. nov.

  Holotype: LACM-DI 158616, a partially articulated skeleton, including some cranial elements but most of the axial column, girdles and limbs.

  Diagnosis: Mid-sized pseudosuchian (total length: approximately 1.5 m; femur length: 17.75 cm) diagnosed by the following unique combination of characters (*indicates autapomorphy, †indicates autapomorphy inferred from phylogenetic analysis): semilunate eminence on middle of ventral ramus of prefrontal*; ventral ramus of prefrontal broadly exposed in lateral view, extensive ventrally and excludes lacrimal from orbit; supratemporal fossa well-exposed dorsally on parietal; high cervical vertebrae count (10–11); low dorsal vertebrae count (10–11)*; dorsal vertebrae with well-developed laminae and deep infradiapophyseal fossae; anterior caudal vertebrae with well-developed, spatulate ribs; anterior caudal ribs asymmetrical in dorsal view, with diagonal bevel on posterolateral edge*; weakly sinusoidal fibular shaft; metatarsal IV longer than metatarsal III†; metatarsal IV subequal in length to metatarsal II†; robust lateral plantar tubercle on ventral face of metatarsal V; dorsal osteoderms in one-to-one, mirrored alignment in dorsal aspect†; osteoderms with indentations creating an ‘hourglass’ waisting in dorsal view*; osteoderms with multiple short spikes on lateral and medial edges.

  Etymology: The generic name combines ‘Benggwi Gwishinga’ from the Shoshone term for ‘catching fish’, with ‘suchus’, the Greek term for Sobek, the Egyptian crocodile-headed god. The specific epithet combines the Latin ‘erema’ and ‘carminis’, meaning ‘desert song’, and honours Elaine Kramer and Monica Shaffer, and their love of the palaeontology, museums, and opera of the southwestern USA. The binomen is intended to translate roughly as ‘Fisherman Croc's desert song’.

Middle Triassic palaeogeographic map with localities of Archosauriformes known from marine settings.

  Locality and age: Fossil Hill Member of the Favret Formation, Favret Canyon, Augusta Mountains, Pershing County, Nevada, USA. The type locality, LACM LOC 8057, is near the top of the north slope of Favret Canyon at an altitude of 1911 m. The horizon pertains to the Frechites occidentalis Zone, which is late Anisian (Middle Triassic) in age.

Nathan D. Smith, Nicole Klein, P. Martin Sander and Lars Schmitz. 2024. A New pseudosuchian from the Favret Formation of Nevada reveals that Archosauriforms occupied Coastal Regions globally during the Middle Triassic. Biol. Lett. 2020240136. DOI: doi.org/10.1098/rsbl.2024.0136

[Paleontology • 2024] Parvosuchus aurelioi • A New small-sized predatory pseudosuchian Archosaur (Pseudosuchia: Gracilisuchidae) from the Middle-Late Triassic of Southern Brazil

 Parvosuchus aurelioi  

Müller, 2024 

   

DOI: 10.1038/s41598-024-63313-3

 Artwork by Matheus Fernandes.

Abstract

Before the rise of dinosaurs and pterosaurs, pseudosuchians—reptiles from the crocodilian lineage—dominated the Triassic land ecosystems. This lineage diversified into several less inclusive clades, resulting in a wide ecomorphological diversity during the Middle and Late Triassic. Some giant pseudosuchians occupied the top of the trophic webs, while others developed extensive bony armor as a defense mechanism, which later evolved as a convergence in the avemetatarsalian lineage. On the other hand, there were groups like the Gracilisuchidae, which was composed of carnivorous forms with lightweight build and less than 1 m in length. The fossil record of gracilisuchids is geographically restricted to China and Argentina, with one ambiguous record from Brazil. In the present study, the first unambiguous gracilisuchid from Brazil is described. Parvosuchus aurelioi gen. et sp. nov. comes from the Dinodontosaurus Assemblage Zone of the Santa Maria Formation, which is associated with the Ladinian-Carnian boundary. Composed of a complete cranium, vertebrae, pelvic girdle and hindlimbs, the new species nests with Gracilisuchus stipanicicorum and Maehary bonapartei in a phylogenetic analysis. Its discovery fills a taxonomic gap in Brazilian pseudosuchian fauna and reveals the smallest known member of this clade from the Dinodontosaurus Assemblage Zone, highlighting the diversity of pseudosuchians during the moment that preceded the dawn of dinosaurs.

 

Skull and lower jaws of Parvosuchus aurelioi gen. et sp. nov.
Holotype (CAPPA/UFSM 0412)
 from the Pinheiros-Chiniquá Sequence (Ladinian-Carnian boundary) of the Santa Maria Supersequence, southern Brazil. 

Provenance of Parvosuchus aurelioi gen. et sp. nov. 
(a) Location and geological context of the Linha Várzea 2 site, Paraíso do Sul, Rio Grande do Sul, Brazil. (b) General view of the Linha Várzea 2 site (taken in January 2023).
(c) Hypothetical reconstruction of the skeleton of the Parvosuchus aurelioi gen. et sp. nov. depicting (in orange) the preserved portions of CAPPA/UFSM 0412. Unpreserved portions are based on the skeletal reconstruction of Gracilisuchus stipanicicorum by Jorge González.

Systematic paleontology

Archosauria Cope, 1869

Pseudosuchia Zittel, 1887–1890

Gracilisuchidae Butler et al., 2014

Parvosuchus aurelioi gen. et sp. nov. 

Holotype: CAPPA/UFSM 0412, a partial skeleton, including a skull with lower jaws, 11 dorsal vertebrae, two sacral vertebrae, a complete pelvic girdle, both femora (lacking the distal portion), partial left tibia, partial left fibula, and left calcaneum.

Etymology: The genus name combines the Latin word “parvus” (= small) and the Greek word “suchus” (= crocodile). The specific epithet honors Pedro Lucas Porcela Aurélio for his passion for paleontology and prospecting, as well as for having discovered the fossil material described here.

Results of the phylogenetic analysis and diversity of the Dinodontosaurus Assemblage Zone of Brazil. (a) Time-calibrated reduced strict consensus tree depicting the phylogenetic position of Parvosuchus aurelioi gen. et sp. nov. Number on nodes represent Bremer support values higher than 1. The temporal bars for each OTU represent the maximum and minimum ages of each geological unit. Divergence times set as approximately 1 million years. (b) Percentage of taxonomic groups recorded in the Dinodontosaurus Assemblage Zone according to the number of species. (c) Approximate body length of pseudosuchian species from the Dinodontosaurus ZA.

Artistic representation of a Middle-Late Triassic landscape of southern Brazil.
(a) A large Prestosuchus chiniquensis feeds on the carcass of a dicynodont while individuals of Parvosuchus aurelioi gen. et sp. nov. compete for scraps. (b) and (c) depict details of individuals of Parvosuchus aurelioi gen. et sp. nov. Artwork by Matheus Fernandes.

Rodrigo T. Müller. 2024. A New small-sized predatory pseudosuchian Archosaur from the Middle-Late Triassic of Southern Brazil. Scientific Reports. 14, 12706. DOI: 10.1038/s41598-024-63313-3

[Paleontology • 2024] Garzapelta muelleri • A New aetosaur (Archosauria: Pseudosuchia) from the Late Triassic (middle Norian) middle Cooper Canyon Formation, Dockum Group, Texas, USA, and its implications on our understanding of the morphological disparity of the aetosaurian dorsal carapace

 Garzapelta muelleri

 Reyes, Martz &  Small, 2024

  

DOI: 10.1002/ar.25379

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Abstract

The Late Triassic Dockum Group in northwestern Texas preserves a rich diversity of pseudosuchian taxa, particularly of aetosaurs. In this contribution, we present Garzapelta muelleri gen. et sp. nov., a new aetosaur from the Late Triassic middle Cooper Canyon Formation (latest Adamanian–earliest Revueltian teilzones) in Garza County, Texas, based on an associated specimen that preserves a significant portion of its dorsal carapace. The carapace of G. muelleri exhibits a striking degree of similarity between that of the paratypothoracin Rioarribasuchus chamaensis and desmatosuchins. We quantitatively assessed the relationships of G. muelleri using several iterations of the matrix. Scoring the paramedian and lateral osteoderms of G. muelleri independently results in conflicting topologies. Thus, it is evident that our current matrix is limited in its ability to discern the convergence within this new taxon and that our current character lists are not fully accounting for the morphological disparity of the aetosaurian carapace. Qualitative comparisons suggest that G. muelleri is a Rioarribasuchus-like paratypothoracin with lateral osteoderms that are convergent with those of desmatosuchins. Although the shape of the dorsal eminence, and the presence of a dorsal flange that is rectangular and proportionately longer than the lateral flange are desmatosuchin-like features of G. muelleri, the taxon does not exhibit the articulation style between the paramedian and lateral osteoderms which diagnose the Desmatosuchini (i.e., a rigid interlocking contact, and an anteromedial edge of the lateral osteoderm that overlaps the adjacent paramedian osteoderm).

Keywords: Aetosaur, Dockum Group, Late Triassic, Revueltian, Texas

William A. Reyes, Jeffrey W. Martz, Bryan J. Small. 2024. Garzapelta muelleri gen. et sp. nov., A New aetosaur (Archosauria: Pseudosuchia) from the Late Triassic (middle Norian) middle Cooper Canyon Formation, Dockum Group, Texas, USA, and its implications on our understanding of the morphological disparity of the aetosaurian dorsal carapace. The Anatomical Record. DOI: 10.1002/ar.25379

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[Paleontology • 2022] Mambawakale ruhuhu • A New Pseudosuchian Archosaur (Pseudosuchia) from the Middle Triassic Manda Beds of Tanzania

Mambawakale ruhuhu 

Butler, Fernandez, Nesbitt, Leite & Gower, 2022

 

DOI: 10.1098/rsos.211622 

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 Life reconstruction by Gabriel Ugueto twitter.com/SerpenIllus

Abstract

The Manda Beds of southwest Tanzania have yielded key insights into the early evolutionary radiation of archosaurian reptiles. Many key archosaur specimens were collected from the Manda Beds in the 1930s and 1960s, but until recently, few of these had been formally published. Here, we describe an archosaur specimen collected in 1963 which has previously been referred to informally as Pallisteria angustimentum. We recognize this specimen as the type of a new taxon, Mambawakale ruhuhu gen. et sp. nov. The holotype and only known specimen of M. ruhuhu comprises a partial skull of large size (greater than 75 cm inferred length), lower jaws and fragments of the postcranium, including three anterior cervical vertebrae and a nearly complete left manus. Mambawakale ruhuhu is characterized by several cranial autapomorphies that allow it to be distinguished with confidence from all other Manda Beds archosaurs, with the possible exception of Stagonosuchus nyassicus for which comparisons are highly constrained due to very limited overlapping material. Phylogenetic analysis suggests that M. ruhuhu is an early diverging pseudosuchian, but more precise resolution is hampered by missing data. Mambawakale ruhuhu is one of the largest known pseudosuchians recovered to date from the Middle Triassic.

Keywords: phylogeny, Pseudosuchia, Triassic, Archosauria, Tanzania

 

Figure 1. Photographs showing the collection of NHMUK R36620, holotype of Mambawakale ruhuhu, in 1963. Alan Charig is sat in the bottom right of the frame in the top left image, and is accompanied by Alfred ‘Fuzz’ Crompton. The top left and bottom right images also show Tanzanians (names unfortunately not recorded in archival material) who were employed by the 1963 expedition team and were critical to its success, discovering many of the fossil sites, constructing roads and carrying excavated fossils out of the field.

Photographs courtesy of Barry Cox and Steve Tolan. Original slides of these photographs are archived at NHMUK.

 Photographs of the skull of NHMUK R36620, holotype of Mambawakale ruhuhu, in right lateral (a) and left lateral (b) views.

Systematic Palaeontology

Archosauria 1869–1870

Pseudosuchia 1887–1890

Mambawakale ruhuhu gen. et sp. nov.

Holotype. NHMUK R36620, partial skull including premaxillae, maxillae, vomers, palatines, pterygoids, ectopterygoids and fragments of the jugals and basipterygoid, with associated hemimandibles, hyoids and isolated maxillary or dentary teeth. These cranial remains are associated (see below) with an incomplete postcranium, including an atlantal intercentrum, partial axis and partial third cervical vertebra, a mostly complete left manus, and additional poorly preserved fragments.

Etymology. Mambawakale, from the Kiswahili words mamba, meaning crocodile, and wakale, meaning ancient. The species name refers to the Ruhuhu Basin from which the type specimen and other taxa from the Manda Beds were collected.

Locality and stratigraphy. Field locality U15/1 of Attridge et al. [1964], Lifua Member of the Manda Beds (Middle Triassic: ?Anisian), Ruhuhu Basin, southwest Tanzania. ...

 Life reconstruction of Mambawakale ruhuhu.
 Only the skull, mandible and a few postcranial elements are known for Mambawakale ruhuhu, so the rest of the body, tail and limbs are reconstructed based on the anatomy of hypothesized close relatives of similar size.

Illustration by Gabriel Ugueto, who retains the copyright.

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Richard J. Butler, Vincent Fernandez, Sterling J. Nesbitt, João Vasco Leite and David J. Gower. 2022. A New Pseudosuchian Archosaur, Mambawakale ruhuhu gen. et sp. nov., from the Middle Triassic Manda Beds of Tanzania. Royal Society Open Science. 9: 211622. DOI: 10.1098/rsos.211622

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