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On the supposed pterosaurian nature of Faxinalipterus minima Bonaparte et al. (2010) from the Upper Triassic of Rio Grande do Sul, Brazil.
... The oldest unequivocal pterosaurs are Norian in age Wild, 1978). Nevertheless, there are few well-preserved specimens of early pterosaurs (Dalla and the pterosaur affinities of some of them have been questioned (Soares et al., 2013). The group has been treated as prolacertiforms (Peters, 2000), early archosauriforms (Bennett, 1996;Benton, 1985) or ornithodirans (Benton, 1990;Nesbitt, 2011;Novas, 1996). ...
Exquisite discoveries and new interpretations regarding an enigmatic group of cursorial avemetatarsalians led to a new phylogenetic hypothesis regarding pterosaur affinities. Previously thought to be dinosaur precursors, lagerpetids are now considered to be the closest relatives to pterosaurs. This new hypothesis sheds light on a new explorable field, especially regarding the character acquisition and evolution within the pterosaur lineage. In the present study, the morphospace occupation of distinct skeletal regions of lagerpetids withing the morphological spectrum of avemetatarsalians is investigated. This approach indicates which portions of the skeleton are more similar to the anatomy of pterosaurs and which portions present different homoplastic signals. The analyses demonstrates that the craniomandibular traits of lagerpetids are pterosaur‐like, the pectoral girdle and forelimb are dinosauromorph‐like and the axial skeleton and the pelvic girdle and hindlimb are unique and highly specialized among the analysed sample. So, despite the close phylogenetic relationships, the postcranial skeleton of lagerpetids and pterosaurs are very different. The occurrence of two distinct and highly specialized groups of pterosauromorphs coexisting with a wide ecological range of dinosauromorphs during Triassic suggests pressure for new niches occupation.
... Located in the municipality of Faxinal do Soturno, State of Rio Grande do Sul, this site has revealed an astonishing quantity and diversity of Norian vertebrates (Bonaparte et al., 2010a;Schultz et al., 2020). After its discovery at the end of the 1990s, this site yielded hundreds of tetrapod remains that stand out for their exceptional preservation, including several cranial and postcranial materials of non-mammaliaform cynodonts (Bonaparte et al., , 2003(Bonaparte et al., , 2010aMartinelli et al., 2005;Oliveira et al., 2011;Soares et al., 2011;Guignard et al., 2019a,b), one partial skeleton of the saurischian dinosaur Guaibasaurus candelariensis (Bonaparte et al., 2007;Agnolín and Martinelli, 2012), remains of a putative pterosaur (Bonaparte et al., 2010b; but see Soares et al., 2013;Dalla Vecchia, 2014), skulls and postcranial elements of procolophonoids (Cisneros and Schultz, 2003), sphenodontians (Ferigolo, 2000;Bonaparte and Sues, 2006;Arantes et al., 2009;Hsiou et al., 2015;Romo-de-Vivar et al., 2015, 2020a, and skull remains of non-rhynchocephalians lepidosauromorphs (Bonaparte et al., 2010a;Romo-de-Vivar et al., 2020b). In addition, fish remains, insects, conchostracans, invertebrate ichnofossils, dinosaur footprints, and gymnosperms have been recovered at the site (Silva et al., 2012;Barboni and Dutra 2013;Rohn et al., 2014), although from overlaying levels. ...
Irajatherium hernandezi is a poorly known non‐mammaliaform cynodont from the Late Triassic of southern Brazil. A new specimen of this cynodont was found in recent fieldwork to the type‐locality, the Linha São Luiz site (Candelária Sequence), providing new insights into the anatomy of this mammalian forerunner. The new specimen comprises a partial skull preserving the left canine, two left and three right postcanines, and an isolated exoccipital; the left dentary with the canine and postcanines; a fragment of the right dentary; the proximal portion of the left partial humerus; the right scapula; and indeterminate fragments. It reveals a new suite of traits for the taxon: rostrum broad and short, possibly as long as the temporal region; three foramina on the lateral surface of the maxilla, that could correspond to the external openings of the rostral alveolar, infraorbital, and zygomaticofacial canals; zygomatic arch slender and postorbital bar absent; temporal fossa is widest at the posterior region; long secondary palate, slightly surpassing the level of the last upper postcanine tooth; cerebral hemispheres of the cranial endocast divided by a median sulcus; scapular blade long and straight, and postscapular fossa absent. Finally, I. hernandezi and other tritheledontids were included in a phylogenetic analysis of Eucynodontia. The analysis recovered unresolved relationships for ictidosaurs/tritheledontids, nested within a polytomy with Tritylodontidae and a clade composed by Pseudotherium argentinus, Botucaraitherium belarminoi, Brasilodon quadrangularis, and Mammaliaformes.
... Based on zircon U-Pb analyses, the maximum depositional age of the fossil-bearing layers is Norian at $225.42 ± 0.37 Mya (Langer et al. 2018). The Linha São Luiz outcrop has produced the procolophonian Soturnia caliodon (Cisneros & Schultz 2003), the rhynchocephalians Clevosaurus brasiliensis (Bonaparte & Sues 2006) and Lanceirosphenodon ferigoloi (Romo de Vivar et al. 2020a), the non-rhynchocephalian lepidosauromorph Cargninia enigmatica (Bonaparte et al. 2010;Romo de Vivar et al. 2020b), an archosaur of uncertain affinities, Faxinalipterus minima (Bonaparte et al. 2010;Soares et al. 2013), the dinosaur Guaibasaurus candelariensis (Bonaparte et al. 1999(Bonaparte et al. , 2007, and the probainognathian cynodonts Brasilodon quadrangularis (¼ Brasilitherium riograndensis, Minicynodon maieri), Riograndia guaibensis and Irajatherium hernandezi (e.g. Bonaparte et al. 2001Bonaparte et al. , 2003Bonaparte et al. , 2005Bonaparte et al. , 2010Bonaparte et al. , 2012Martinelli et al. 2005Martinelli et al. , 2017Oliveira et al. 2011;Soares et al. 2011). ...
Rhynchocephalians are a group of lizard-like diapsid reptiles that were very diverse during the Mesozoic but are now restricted to a single extant genus in New Zealand. Recent cladistic analyses have revealed two major clades, Eusphenodontia and the more crownward Neosphenodontia, but relationships of individual taxa have remained difficult to determine because of missing data and an unrevised data matrix. Here we drastically revise the established data matrix on rhynchocephalians by reassessing, evaluating, and adding new characters and operational taxonomic units, differing from any previous analyses in our goal to consider all known rhynchocephalians. In addition, we describe a new genus and species of an early eusphenodontian taxon from the Norian of southern Brazil, with a unique mosaic of plesiomorphic and apomorphic traits, and we re-examine the craniodental anatomy of the eusphenodontian Clevosaurus brasiliensis with µCT imaging, revealing a unique form of acrodonty amongst rhynchocephalians.
http://zoobank.org/urn:lsid:zoobank.org:pub:A9211C5A-D4F9-472A-B8AB-877D13ABFDD5
... These layers are referred to the Riograndia Assemblage Zone (Norian in age) of the Candelária Sequence (Santa Maria Supersequence;Horn et al., 2014;Langer et al., 2018). In addition to Cargninia, the Linha São Luiz outcrop has produced the procolophonian Soturnia caliodon (Cisneros and Schultz, 2003); the sphenodontians Clevosaurus brasiliensis (Bonaparte and Sues, 2006) and a new taxon (Romo de Vivar et al., submitted); the archosaur of uncertain affinities Faxinalipterus minima (Bonaparte et al., 2010;Soares et al., 2013); the dinosaur Guaibasaurus candelariensis (Bonaparte et al., 1999); and the probainognathian cynodonts Brasilodon quadrangularis, Brasilitherium riograndensis, Minicynodon maieri, Riograndia guaibensis, and Irajatherium hernandezi (e.g., Bonaparte et al., 2001Bonaparte et al., , 2003Bonaparte et al., , 2005Bonaparte et al., , 2012Martinelli et al., 2005;Oliveira et al., 2011;Soares et al., 2011). ...
In this contribution, we re-describe the holotype (i.e., the posterior fragment of a left dentary with dentition) of Cargninia enigmatica from the Riograndia Assemblage Zone, Candelária Sequence, Santa Maria Supersequence (Upper Triassic, Brazil), originally considered a member of the Lepidosauria. In addition, two other specimens of lepidosauromorphs from the same locality are described and compared. Broad comparisons suggest that C. enigmatica possesses a unique combination of features, but several key features are widely distributed among basal non-rhynchocephalian lepidosauromorphs and kuehneosaurids. Thus, two possible scenarios are proposed: (1) Cargninia is a basal non-lepidosaurian lepidosauromorph, or (2) it is a basal lepidosaurian. The new specimens are a portion of a right maxilla with teeth (in two fragments) and a fragment of a dentary with teeth. The first specimen is identified as a lepidosauromorph because the maxilla cannot be directly compared with the holotype of C. enigmatica and it is difficult to evaluate if the differences in the dentition (upper versus lower teeth) are the result of intra-or interspecific variation. The dentary, on the other hand, is tentatively referred to C. enigmatica. These specimens together add new clues to understanding the early evolution of Lepidosauromorpha.
... Whitin Ornithodira, a possible basal form is the small Faxinalipterus minima, found in the Linha São Luiz site (Bonaparte et al., 2010b;Soares et al., 2013). Non-dinosaurian Dinosauriformes are represented by the Silesauridae Sacisaurus agudoensis, the most conspicuous fossil of the Sacisaurus site as it is alluded by the name of the outcrop (Ferigolo and Langer, 2007;Langer and Ferigolo, 2013). ...
... The Riograndia AZ (top of the Candel aria Sequence, Santa Maria Supersequence; Zerfass et al. 2003;Soares et al. 2011;Horn et al. 2014 Soares et al. 2013) and several probainognathian cynodonts (e.g. Brasilodon quadrangularis, Brasilitherium riograndensis, Minicynodon maieri, Riograndia guaibensis, Irajatherium hernandezi; Bonaparte et al. 2001Bonaparte et al. , 2003Bonaparte et al. , 2005Bonaparte et al. , 2012Martinelli et al. 2005;Soares et al. 2011;Oliveira et al. 2011). ...
We describe a new eusphenodontian, Lanceirosphenodon ferigoloi gen. et sp. nov., from the Upper Triassic (Norian) Riograndia Assemblage Zone (AZ) of the Candelária Sequence (Santa Maria Supersequence) of Rio Grande do Sul, Brazil. The new taxon consists of an almost complete left dentary with dentition, which exhibits a mosaic of features considered ‘typical’ of non-eusphenodontian rhynchocephalians, along with others reported for eusphenodontian taxa. It has the typical rhynchocephalian regionalized dentition with 19 teeth and also pleuroacrodont implantation; the additional dentition presents alternation of size and shape, with the last additional teeth resembling a spear in labial view. A well-developed chin is also present. Our phylogenetic analysis places Lanceirosphenodon as one of the most basal eusphenodontians and reinforces the hypothesis that Rhynchocephalia underwent an early diversification, probably in the Early Triassic, followed by an explosion in morphological disparity. Based on the ontogenetic sequence of Sphenodon, Lanceirosphenodon fitted between stages T2 and T3, representing a probable early juvenile individual. In spite of its ontogenetic stage, the set of characters present in Lanceirosphenodon, including two autapomorphies, supports its recognition as a new taxon. This new taxon increases our knowledge of the faunal diversity in the Triassic of Gondwana and more locally for the Riograndia Assemblage Zone of southern Brazil.
https://zoobank.org:pub:1849FF5A-B5D3-484B-B16C-7D952AF62A26
... P. Upchurch et al. 2006). Similarly, Bonaparte et al. (2006) reported pterosaurian remains from the Carnian of Brazil, but the affinities of this material remain poorly understood and it is not certain that it represents a true pterosaur (Dalla Vecchia 2013) and it has recently been reinterpreted as a basal ornithodiran (Soares et al. 2013). The only other occurrences of pterosaurs in the Late Triassic are records from the Norian and Rhaetian of Greenland and Europe. ...
The biogeographical history of pterosaurs has received very little treatment. Here, we present the first quantitative analysis of pterosaurian biogeography based on an event-based parsimony method (Treefitter). This approach was applied to a phylogenetic tree comprising the relationships of 108 in-group pterosaurian taxa, spanning the full range of this clade's stratigraphical and geographical extent. The results indicate that there is no support for the impact of vicariance or coherent dispersal on pterosaurian distributions. However, this group does display greatly elevated levels of sympatry. Although sampling biases and taxonomic problems might have artificially elevated the occurrence of sympatry, we argue that our results probably reflect a genuine biogeographical signal. We propose a novel model to explain pterosaurian distributions: pterosaurs underwent a series of ‘sweep-stakes’ dispersal events (across oceanic barriers in most cases), resulting in the founding of sympatric clusters of taxa. Examination of the spatiotemporal distributions of pterosaurian occurrences indicates that their fossil record is extremely patchy. Thus, while there is likely to be genuine information on pterosaurian diversity and biogeographical patterns in the current data-set, caution is required in its interpretation.
... This is the idea that Witton favours, which is fair enough since there are unpublished studies showing that the crown-archosaur hypothesis is supported even when oddball taxa considered close to pterosaurs by some (Peters 2000) are included in the analysis too. Nevertheless, the crown-archosaur idea does look odd given that we lack taxa that appear in any way transitional between pterosaurs and other ornithodirans (Faxinalipterus minima -published in 2010 as a possible sistertaxon to the rest of Pterosauria -is not a pterosaur, nor obviously close to pterosaurs at all (Soares et al. 2013)). ...
Faxinalipterus minimus was originally described as a purported pterosaur from the Late Triassic (early Norian) Caturrita Formation of southern Brazil. Its holotype comprises fragmentary postcranial elements, whereas a partial maxilla was referred to the species. The assignment of Faxinalipterus minimus to Pterosauria has been questioned by some studies, but the specimen has never been accessed in detail after its original description. Here we provide a reassessment of Faxinalipterus minimus after additional mechanical preparation of the holotype. Our interpretations on the identity of several bones differ from those of the original description, and we found no support favoring pterosaur affinities for the taxon. The maxilla previously referred to Faxinalipterus minimus is disassociated from this taxon and referred to a new putative pterosauromorph described here from a partial skull and fragmentary postcranial elements. Maehary bonapartei gen. et sp. nov. comes from the same fossiliferous site that yielded Faxinalipterus minimus, but the lack of overlapping bones hampers comparisons between the two taxa. Our phylogenetic analysis places Faxinalipterus minimus within Lagerpetidae and Maehary bonapartei gen. et sp. nov. as the earliest-diverging member of Pterosauromorpha. Furthermore, the peculiar morphology of the new taxon reveals a new dental morphotype for archosaurs, characterized by conical, unserrated crowns, with a pair of apicobasally oriented grooves. These two enigmatic archosaurs expand our knowledge on the Caturrita Formation fauna and reinforce the importance of its beds on the understanding of Late Triassic ecosystems.
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