A new small-sized predatory pseudosuchian archosaur from the Middle-Late Triassic of Southern Brazil.

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.

The postcranial skeleton of Teyujagua paradoxa (Reptilia: Archosauromorpha) from the early Triassic of South America.

Teyujagua paradoxa is a remarkable early archosauromorph from the Lower Triassic Sanga do Cabral Formation, Brazil. The species was originally described from an almost complete skull and a few associated cervical vertebrae, and no further postcranial elements were known at that time. Additional fieldwork in the Sanga do Cabral Formation, however, was successful in recovering a fairly complete postcranial skeleton attributable to the holotype. Here, we describe this new postcranial material, which is composed of cervical, dorsal, sacral and caudal vertebrae, limbs, pectoral and pelvic girdles, ribs, and gastralia. The description of its postcranial skeleton makes T. paradoxa one of the best-known early-diverging archosauromorphs. The cladistic analysis performed after the scoring of postcranial data recovered T. paradoxa in the same position initially described, close to the node that defines the Archosauriformes. Teyujagua paradoxa shares morphological features with representatives of early-diverging archosauromorphs and archosauriforms, with certain traits demonstrating a mosaic of plesiomorphic and apomorphic character states. We also performed partitioned morphospace and disparity analysis to elucidate the morphological disparity and evolutionary patterns among archosauromorphs. Teyujagua paradoxa occupies a notable position, suggesting an intermediate morphology between early archosauromorphs and proterosuchids. Disparity estimates highlighted Pseudosuchia and Avemetatarsalia as having the highest median disparity, reflecting their diverse cranial and postcranial morphologies, respectively. These findings offer valuable insights into archosauromorph macroevolution and adaptation.

Virtual endocasts of Clevosaurus brasiliensis and the tuatara: Rhynchocephalian neuroanatomy and the oldest endocranial record for Lepidosauria.

Understanding the origins of the vertebrate brain is fundamental for uncovering evolutionary patterns in neuroanatomy. Regarding extinct species, the anatomy of the brain and other soft tissues housed in endocranial spaces can be approximated by casts of these cavities (endocasts). The neuroanatomical knowledge of Rhynchocephalia, a reptilian clade exceptionally diverse in the early Mesozoic, is restricted to the brain of its only living relative, Sphenodon punctatus, and unknown for fossil species. Here, we describe the endocast and the reptilian encephalization quotient (REQ) of the Triassic rhynchocephalian Clevosaurus brasiliensis and compare it with an ontogenetic series of S. punctatus. To better understand the informative potential of endocasts in Rhynchocephalia, we also examine the brain-endocast relationship in S. punctatus. We found that the brain occupies 30% of its cavity, but the latter recovers the general shape and length of the brain. The REQ of C. brasiliensis (0.27) is much lower than S. punctatus (0.84-1.16), with the tuatara being close to the mean for non-avian reptiles. The endocast of S. punctatus is dorsoventrally flexed and becomes more elongated throughout ontogeny. The endocast of C. brasiliensis is mostly unflexed and tubular, possibly representing a more plesiomorphic anatomy in relation to S. punctatus. Given the small size of C. brasiliensis, the main differences may result from allometric and heterochronic phenomena, consistent with suggestions that S. punctatus shows peramorphic anatomy compared to Mesozoic rhynchocephalians. Our results highlight a previously undocumented anatomical diversity among rhynchocephalians and provide a framework for future neuroanatomical comparisons among lepidosaurs.

New reptile shows dinosaurs and pterosaurs evolved among diverse precursors.

Dinosaurs and pterosaurs have remarkable diversity and disparity through most of the Mesozoic Era1-3. Soon after their origins, these reptiles diversified into a number of long-lived lineages, evolved unprecedented ecologies (for example, flying, large herbivorous forms) and spread across Pangaea4,5. Recent discoveries of dinosaur and pterosaur precursors6-10 demonstrated that these animals were also speciose and widespread, but those precursors have few if any well-preserved skulls, hands and associated skeletons11,12. Here we present a well-preserved partial skeleton (Upper Triassic, Brazil) of the new lagerpetid Venetoraptor gassenae gen. et sp. nov. that offers a more comprehensive look into the skull and ecology of one of these precursors. Its skull has a sharp, raptorial-like beak, preceding that of dinosaurs by around 80 million years, and a large hand with long, trenchant claws that firmly establishes the loss of obligatory quadrupedalism in these precursor lineages. Combining anatomical information of the new species with other dinosaur and pterosaur precursors shows that morphological disparity of precursors resembles that of Triassic pterosaurs and exceeds that of Triassic dinosaurs. Thus, the 'success' of pterosaurs and dinosaurs was a result of differential survival among a broader pool of ecomorphological variation. Our results show that the morphological diversity of ornithodirans started to flourish among early-diverging lineages and not only after the origins of dinosaurs and pterosaurs.

Palaeohistology reveals an unusual periodontium and tooth implantation in a filter-feeding pterodactyloid pterosaur, Pterodaustro guinazui, from the Lower Cretaceous of Argentina.

Pterosaurs are an extinct group of Mesozoic flying reptiles, which exhibited high diversity with regard to their dentition. Although morphological features of pterosaur dentition have been described in detail in several contributions, the histology of tooth and tooth attachment tissues (i.e. periodontium) has been scarcely analysed to date for this clade. Here we describe and interpret the microstructure of the tooth and periodontium attachment tissues of Pterodaustro guinazui, a filter-feeding pterodactyloid pterosaur from the Lower Cretaceous of Argentina. The histological analysis of the lower jaw and its filamentous teeth verifies that the geometry of the implantation corresponds to an aulacodont condition (i.e. teeth are set in a groove with no interdental separation). This pattern departs from that recorded in other archosaurs, being possibly also present in other, non-closely related, pterosaurs. Regarding tooth attachment, in contrast to other pterosaurs, there is no direct evidence for gomphosis in Pterodaustro (i.e. the absence of cementum, mineralized periodontal ligamentum and alveolar bone). Nevertheless, the current evidence for ankylosis is still not conclusive. Contrary to that reported for other archosaurs, replacement teeth are absent in Pterodaustro, which is interpreted as evidence for monophyodonty or diphyodonty in this taxon. Most of the microstructural features are possibly related to the complex filter-feeding apparatus of Pterodaustro and does not appear to represent the general pattern of pterosaurs.

Macro- and microscopic brain anatomy of the amazon lava lizard (Tropidurus torquatus) (WIED, 1820) / Anatomia macro- e microscópica do encéfalo do calango (Tropidurus torquatus) (WIED, 1820)

Reptiles have a key role in understanding amniotes' reproductive independence of water. Many adaptations arose, including in locomotor patterns and behaviours, and the nervous system adapted to those new habits.We have described the macroscopic anatomy and cytoarchitecture of the Amazon Lava Lizard brain (Tropidurus torquatus), an abundant lizard in South America. Fifteen specimens were captured, euthanized and their brains were dissected, eight of these were processed and stained in haematoxylineosin. Their main areas of the brain are the telencephalon and diencephalon, in the forebrain, tectum and tegmentum, in the midbrain and bulbota and cerebellum, in the hindbrain. The main and accessory olfactory bulbs are the most rostral structure of the brain and are composed of six layers. Brain hemispheres compose the telencephalon and are divided in pallium and subpallium. Medial, dorsomedial, lateral and dorsal cortices are part of the pallium. Striatum, pallidum and septum compose the subpallium. The diencephalon is composed of thalamus, epithalamus and hypothalamus. The midbrain has a ventral tegmentum, composed of torus semicircularis and a dorsal 14 layered optic tectum. Most part of the hindbrain is composed of the bulbo, and the cerebellum arises from it, forming a three-layered plate like structure. In general, the brain of Tropidurus torquatusresembles those of other lizards, with its own adaptations

Os répteis têm um papel fundamental para a compreensão da independência reprodutiva da água que surgiu nos amniotas. Várias adaptações ocorreram, inclusive em padrões e comportamentos locomotores, e o sistema nervoso se adaptou a esses novos hábitos. Descrevemos a anatomia macroscópica e a citoarquitetura do encéfalo do calango (Tropidurus torquatus), um lagarto abundante na América do Sul. Quinze espécimes foram capturados, eutanasiados e seus encéfalos dissecados, oito destes foram processados e corados em hematoxilina-eosina. As principais áreas do cérebro são o telencéfalo e o diencéfalo, na parte anterior do encéfalo, teto e tegmento, no mesencéfalo e bulbo e cerebelo, na parte posterior do encéfalo. Os bulbos olfatórios principais e acessórios são as estruturas mais rostrais do cérebro e são compostos por seis camadas. Os hemisférios cerebrais compõem o telencéfalo e são divididos em pálio e subpálio. Os córtices medial, dorsomedial, lateral e dorsal fazem parte do pálio. Estriado, pálido e septo compõem o subpálio. O diencéfalo é composto pelo tálamo, epitálamo e hipotálamo. O mesencéfalo possui um tegmento ventral, composto de torus semicircularis e um tecto óptico dorsal com 14 camadas. A maior parte da parte posterior do encéfalo é composta pelo bulbo, e o cerebelo surge como uma projeção dessa estrutura, em formato plano, com três camadas. Em geral, o encéfalo de Tropidurus torquatusse assemelha ao de outros lagartos, com suas próprias adaptações.

Novel information on the cranial anatomy of the tapejarine pterosaur Caiuajara dobruskii.

Caiuajara dobruskii is a tapejarid pterosaur from the Cretaceous of the 'Cemitério dos Pterossauros' (pterosaur graveyard) site, a unique pterosaur bonebed which is located at the municipality of Cruzeiro do Oeste (Paraná, Brazil). Preliminary inferences on Caiuajara morphology were founded on a few partial skeletons, with no detail on the skull anatomy. Here we describe a new specimen from the pterosaur graveyard site, which corresponds to the most complete skull of Caiuajara dobruskii known so far. Furthermore, we describe and compare other specimens including the holotype, a paratype, and several other undescribed specimens. The new specimen preserves the posterior portion of the skull, allowing a better comprehension of its morphology and provides an appreciation of the anatomic structures of the basicranium, enabling better interpretation of this region. We also described the lower jaw of Caiuajara, reporting a unique feature of its symphyseal which adds to the diagnosis for the species. A variability in the premaxillary crest is also noted in different specimens of Caiuajara, which might be interpreted as sexual dimorphism or ontogenetic variability. Therefore, those new findings allow a better comprehension of its skull and enables a more precise comparison between the skulls of those extinct flying reptiles.

Diphyodont tooth replacement of Brasilodon-A Late Triassic eucynodont that challenges the time of origin of mammals.

Two sets of teeth (diphyodonty) characterise extant mammals but not reptiles, as they generate many replacement sets (polyphyodonty). The transition in long-extinct species from many sets to only two has to date only been reported in Jurassic eucynodonts. Specimens of the Late Triassic brasilodontid eucynodont Brasilodon have provided anatomical and histological data from three lower jaws of different growth stages. These reveal ordered and timed replacement of deciduous by adult teeth. Therefore, this diphyodont dentition, as contemporary of the oldest known dinosaurs, shows that Brasilodon falls within a range of wide variations of typically mammalian, diphyodont dental patterns. Importantly, these three lower jaws represent distinct ontogenetic stages that reveal classic features for timed control of replacement, by the generation of only one replacement set of teeth. This data shows that the primary premolars reveal a temporal replacement pattern, importantly from directly below each tooth, by controlled regulation of tooth resorption and regeneration. The complexity of the adult prismatic enamel structure with a conspicuous intra-structural Schmelzmuster array suggests that, as in the case of extant mammals, this extinct species would have probably sustained higher metabolic rates than reptiles. Furthermore, in modern mammals, diphyodonty and prismatic enamel are inextricably linked, anatomically and physiologically, to a set of other traits including placentation, endothermy, fur, lactation and even parental care. Our analysis of the osteodental anatomy of Brasilodon pushes back the origin of diphyodonty and consequently, its related biological traits to the Norian (225.42 ± 0.37 myr), and around 25 myr after the End-Permian mass extinction event.

Fingers zipped up or baby mittens? Two main tetrapod strategies to return to the sea.

The application of network methodology in anatomical structures offers new insights on the connectivity pattern of skull bones, skeletal elements and their muscles. Anatomical networks helped to improve our understanding of the water-to-land transition and how the pectoral fins were transformed into limbs via their modular disintegration. Here, we apply the same methodology to tetrapods secondarily adapted to the marine environment. We find that these animals achieved their return to the sea with four types of morphological changes, which can be grouped into two different main strategies. In all marine mammals and the majority of the reptiles, the fin is formed by the persistence of superficial and interdigital connective tissues, like a 'baby mitten', whereas the underlying connectivity pattern of the bones does not influence the formation of the forefin. On the contrary, ichthyosaurs 'zipped up' their fingers and transformed their digits into carpal-like elements, forming a homogeneous and better-integrated forefin. These strategies led these vertebrates into three different macroevolutionary paths exploring the possible spectrum of morphological adaptations.

Reptile diversity in the Duas Bocas Biological Reserve, Espírito Santo, southeastern Brazil

The lack of information on the occurrence of species in a region limits the understanding of the composition and structure of the local community and, consequently, restricts the proposition of effective measures for species conservation. In this study, we researched the reptiles in the Duas Bocas Biological Reserve (DBBR), Espírito Santo, southeastern Brazil. We analyzed the parameters of the local community, such as richness, composition, and abundance of species. We conducted samplings from August 2017 to January 2019, through active search. We performed the samplings in nine standard plots of 250 meters in length. All individuals located in the plots or occasionally on the trails were registered. To evaluate sample effort to characterize the reptile community, we performed an accumulation curve of species, and to update the DBBR reptile list, we used as secondary data specimens deposited in collections and previously published studies. Considering primary and secondary data, we recorded 38 species, one chelonia, 13 lizards, and 24 snakes. Our study showed a richness of 15 additional species to the previous list of reptiles, increasing by about 40% the known richness to the area. We concluded that the DBBR holds a high richness of reptile species, representing 12% of the richness of reptiles of the Atlantic Forest and with a considerable number of endemic species in this biome. This suggests that the DBBR is an important forest fragment constituting a reservoir of the biodiversity of the reptiles of the Atlantic Forest.(AU)

A new archosauromorph from South America provides insights on the early diversification of tanystropheids.

After the Permo-Triassic mass extinction, the archosauromorph fossil record is comparatively abundant and ecologically diverse. Among early archosauromorphs, tanystropheids gained considerable attention due to the presence of extreme skeletal adaptations in response to sometimes overspecialized lifestyles. The origin and early radiation of Tanystropheidae, however, remains elusive. Here, a new Early Triassic archosauromorph is described and phylogenetically recovered as the sister-taxon of Tanystropheidae. The new specimen, considered a new genus and species, comprises a complete posterior limb articulated with pelvic elements. It was recovered from the Sanga do Cabral Formation (Sanga do Cabral Supersequence, Lower Triassic of the Paraná Basin, Southern Brazil), which has already yielded a typical Early Triassic vertebrate assemblage of temnospondyls, procolophonoids, and scarce archosauromorph remains. This new taxon provides insights on the early diversification of tanystropheids and represents further evidence for a premature wide geographical distribution of this clade. The morphology of the new specimen is consistent with a terrestrial lifestyle, suggesting that this condition was plesiomorphic for Tanystropheidae.

A rostral neurovascular system in the mosasaur Taniwhasaurus antarcticus.

Mosasaurs were a cosmopolitan group of marine squamate reptiles that lived during the Late Cretaceous period. Tylosaurinae mosasaurs were characterized for having an edentulous rostrum anterior to the premaxillary teeth. External morphology of the snout of the tylosaurine Taniwhasaurus antarcticus from the Upper Cretaceous beds at James Ross Island (Antarctic Peninsula) shows a complex anatomy with diverse large foramina and bone sculpture. A computed tomography scan of the Taniwhasaurus rostrum revealed a complex internal neurovascular system of branched channels in the anteriormost part of the snout. Systems like this are present in extant aquatic vertebrates such as cetaceans and crocodiles to aid them with prey detection, and are inferred to have functioned in a similar manner for several extinct reptile clades such as plesiosaurs and ichthyosaurs. Thus, it is probable that Taniwhasaurus also was able to detect prey with an enhanced neural system located in its rostrum. This condition may be more widespread than previously thought among mosasaurs and other marine reptiles.

Braincase anatomy of Almadasuchus figarii (Archosauria, Crocodylomorpha) and a review of the cranial pneumaticity in the origins of Crocodylomorpha.

Almadasuchus figarii is a basal crocodylomorph recovered from the Upper Jurassic levels of the Cañadón Calcáreo Formation (Oxfordian-Tithonian) of Chubut, Argentina. This taxon is represented by cranial remains, which consist of partial snout and palatal remains; an excellently preserved posterior region of the skull; and isolated postcranial remains. The skull of the only specimen of the monotypic Almadasuchus was restudied using high-resolution computed micro tomography. Almadasuchus has an apomorphic condition in its skull shared with the closest relatives of crocodyliforms (i.e. hallopodids) where the quadrates are sutured to the laterosphenoids and the otoccipital contacts the quadrate posterolaterally, reorganizing the exit of several cranial nerves (e.g. vagus foramen) and the entry of blood vessels (e.g. internal carotids) on the occipital surface of the skull. The endocast is tubular, as previously reported in thalattosuchians, but has a marked posterior step, and a strongly projected floccular recess as in other basal crocodylomorphs. Internally, the skull of Almadasuchus is heavily pneumatized, where different air cavities invade the bones of the suspensorium and braincase, both on its dorsal or ventral parts. Almadasuchus has a large basioccipital recess, which is formed by cavities that excavate the basioccipital and the posterior surface of the basisphenoid, and unlike other crocodylomorphs is connected with the basisphenoid pneumatizations. Ventral to the otic capsule, a pneumatic cavity surrounded by the otoccipital and basisphenoid is identified as the rhomboidal recess. The quadrate of Almadasuchus is highly pneumatized, being completely hollow, and the dorsal pneumatizations of the braincase are formed by the mastoid and facial antra, and a laterosphenoid cavity (trigeminal diverticulum). To better understand the origins of pneumatic features in living crocodylomorphs we studied cranial pneumaticity in the basal members of Crocodylomorpha and found that: (a) prootic pneumaticity may be a synapomorphy for the whole clade; (b) basisphenoid pneumaticity (pre-, postcarotid and rostral recesses) is a derived feature among basal crocodylomorphs; (c) quadrate pneumatization is acquired later in the history of the group; and (d) the rhomboidal sinus is a shared derived trait of hallopodids and crocodyliforms. The marine thallatosuchians exhibit a reduction of the pneumaticity of the braincase and this reduction is evaluated considering the two phylogenetic positions proposed for the clade.

Unique Tooth Morphology and Prismatic Enamel in Late Cretaceous Sphenodontians from Argentina.

Mammals and reptiles have evolved divergent adaptations for processing abrasive foods. Mammals have occluding, diphyodont dentitions with taller teeth (hypsodonty), more complex occlusal surfaces, continuous tooth eruption, and forms of prismatic enamel that prolong the functional life of each tooth [1, 2]. The evolution of prismatic enamel in particular was a key innovation that made individual teeth more resilient to abrasion in early mammals [2-4]. In contrast, reptiles typically have thin, non-prismatic enamel, and shearing, polyphyodont dentitions with multi-cusped or serrated tooth crowns, multiple tooth rows, rapid tooth replacement rates, or batteries made of hundreds of teeth [5-9]. However, there are rare cases where reptiles have evolved alternative solutions to cope with abrasive diets. Here, we show that the combined effects of herbivory and an ancestral loss of tooth replacement in a lineage of extinct herbivorous sphenodontians, distant relatives of the modern tuatara (Sphenodon punctatus) [10], are associated with the evolution of wear-resistant and highly complex teeth. Priosphenodon avelasi, an extinct sphenodontian from the Cretaceous of Argentina, possesses a unique cone-in-cone dentition with overlapping generations of teeth forming a densely packed tooth file. Each tooth is anchored to its predecessor via a rearrangement of dental tissues that results in a novel enamel-to-bone tooth attachment. Furthermore, the compound occlusal surfaces, thickened enamel, and the first report of prismatic enamel in a sphenodontian are convergent strategies with those in some mammals, challenging the perceived simplicity of acrodont dentitions [11-15] and showcasing the reptilian capacity to produce complex and unusual dentitions.

Reptile diversity in the Duas Bocas Biological Reserve, Espírito Santo, southeastern Brazil

The lack of information on the occurrence of species in a region limits the understanding of the composition and structure of the local community and, consequently, restricts the proposition of effective measures for species conservation. In this study, we researched the reptiles in the Duas Bocas Biological Reserve (DBBR), Espírito Santo, southeastern Brazil. We analyzed the parameters of the local community, such as richness, composition, and abundance of species. We conducted samplings from August 2017 to January 2019, through active search. We performed the samplings in nine standard plots of 250 meters in length. All individuals located in the plots or occasionally on the trails were registered. To evaluate sample effort to characterize the reptile community, we performed an accumulation curve of species, and to update the DBBR reptile list, we used as secondary data specimens deposited in collections and previously published studies. Considering primary and secondary data, we recorded 38 species, one chelonia, 13 lizards, and 24 snakes. Our study showed a richness of 15 additional species to the previous list of reptiles, increasing by about 40% the known richness to the area. We concluded that the DBBR holds a high richness of reptile species, representing 12% of the richness of reptiles of the Atlantic Forest and with a considerable number of endemic species in this biome. This suggests that the DBBR is an important forest fragment constituting a reservoir of the biodiversity of the reptiles of the Atlantic Forest.

Análise histológica do segmento sexual renal de Suaçuboia / Histological analysis of the renal sexual segment of Suaçuboia

Corallus hortulanus is a snake with wide geographical distribution and valid ecological importance. However, information about their reproductive biology is scarce and most of the data obtained is from snakes in captivity. Thus, the work aimed to describe the histological aspects of the sexual segment of the kidney (SSK), a specialized part of the kidneys. Therefore, histological analysis and measurement of SSK were performed from 12 specimens of Corallus hortulanus collected in different months of the year. The histological aspects of the SSK observed were similar to those described for other species of snakes and the tubular segments had an average diameter of 76.8 ± 25.6 µm. However, a great variation was observed in the morphological aspects (hypertrophy and presence and disposition of granules) and in the diameter of the tubular segments among the individuals analyzed, apparently related to reproductive seasonality. The results obtained in this study contribute to a greater understanding of the reproductive aspects of C. hortulanus and the possible seasonal variations should be better investigated.

Análise histológica do segmento sexual renal de Suaçuboia / Histological analysis of the renal sexual segment of Suaçuboia

Corallus hortulanus is a snake with wide geographical distribution and valid ecological importance. However, information about their reproductive biology is scarce and most of the data obtained is from snakes in captivity. Thus, the work aimed to describe the histological aspects of the sexual segment of the kidney (SSK), a specialized part of the kidneys. Therefore, histological analysis and measurement of SSK were performed from 12 specimens of Corallus hortulanus collected in different months of the year. The histological aspects of the SSK observed were similar to those described for other species of snakes and the tubular segments had an average diameter of 76.8 ± 25.6 µm. However, a great variation was observed in the morphological aspects (hypertrophy and presence and disposition of granules) and in the diameter of the tubular segments among the individuals analyzed, apparently related to reproductive seasonality. The results obtained in this study contribute to a greater understanding of the reproductive aspects of C. hortulanus and the possible seasonal variations should be better investigated.(AU)

First complete pterosaur from the Afro-Arabian continent: insight into pterodactyloid diversity.

Despite being known from every continent, the geological record of pterosaurs, the first group of vertebrates to develop powered flight, is very uneven, with only a few deposits accounting for the vast majority of specimens and almost half of the taxonomic diversity. Among the regions that stand out for the greatest gaps of knowledge regarding these flying reptiles, is the Afro-Arabian continent, which has yielded only a small number of very fragmentary and incomplete materials. Here we fill part of that gap and report on the most complete pterosaur recovered from this continent, more specifically from the Late Cretaceous (~95 mya) Hjoûla Lagerstätte of Lebanon. This deposit is known since the Middle Ages for the exquisitely preserved fishes and invertebrates, but not for tetrapods, which are exceedingly rare. Mimodactylus libanensis gen. et sp. nov. differs from the other Afro-Arabian pterosaur species named to date and is closely related to the Chinese species Haopterus gracilis, forming a new clade of derived toothed pterosaurs. Mimodactylidae clade nov. groups species that are related to Istiodactylidae, jointly designated as Istiodactyliformes (clade nov.). Istiodactyliforms were previously documented only in Early Cretaceous sites from Europe and Asia, with Mimodactylus libanensis the first record in Gondwana.

Amphisbaenia: adaptações para o modo de vida fossorial / Amphisbaenia: adaptations to the fossorial lifestyle

Amphisbaenia são répteis fossoriais, que vivem em sistemas de túneis construídos por eles mesmos. Atualmente, são descritas 195 espécies recentes. O objetivo deste estudo foi reunir informações bibliográficas sobre aspectos de sua morfologia, fisiologia e comportamento relacionando-as ao hábito fossorial. O principal instrumento de escavação dos anfisbênios é a cabeça, cuja morfologia está relacionada com a maneira como a escavação é realizada. Assim, nas espécies com a cabeça arredondada o mecanismo de escavação é generalizado e nas espécies com a cabeça em forma-de-pá, de espátula ou com uma quilha vertical é especializado. O crânio é resistente, formado por placas ósseas rígidas, que devem suportar as investidas da cabeça. O corpo é alongado e cilíndrico desprovido de membros, na maioria, e formado por anéis tegumentares, importantes no deslocamento retilíneo do corpo para a frente e para trás, dentro dos túneis. O alongamento do corpo é refletido nos órgãos internos que são, em sua maioria, alongados; os órgãos pares tendem a sofrer redução ou deslocamento unilateral. Como estratégias de defesa utilizam-se da autotomia caudal, exibição da cauda ou salto de fuga. São predadores que se alimentam, normalmente, de insetos e suas larvas, apreendidos por mandíbulas potentes, dentes fortes e recurvados. O sistema visual é reduzido, no entanto, são capazes de perceber sons e vibrações oriundas do substrato, e possuem um acurado senso químico. A maioria das espécies é ovípara com um baixo número de ovos por ninhada e o ciclo sexual é geralmente sazonal, sincronizado com a estação quente e chuvosa, mas outros aspectos relacionados ao comportamento reprodutivo das espécies ainda são desconhecidos. Exibem termorregulação comportamental e selecionam micro-habitat com temperaturas mais favoráveis às suas atividades, realizando migrações verticais no solo, de acordo com a temperatura ambiental e estações do ano...

Amphisbaenia are fossorial reptiles, which live in tunnel systems built by themselves. Currently, 195 species are described. The objective of this study was to gather bibliographic information on aspects of their morphology, physiology and behavior related to the fossorial habit. The main digging tool of the amphisbaenians is the head, whose morphology is related to the way excavation is carried out. In round-headed species, the mechanism is generalized, and in species with a paddle-shaped head, a spatula or a vertical keel, is specialized. The skull is sturdy, consisting of rigid bony plates, which must support the head thrust. The body is elongated and cylindrical, devoid of limbs, mostly formed by integumentary rings, important in the rectilinear displacement of the body back and forth within the tunnels. The elongation of the body is reflected in the internal organs which are, for the most part, elongated; the paired organs tend to undergo unilateral reduction or displacement. As a defense strategy they use caudal autotomy, tail exhibit or escape jump. They are predators that normally feed on insects and their larvae, caught by powerful jaws, strong recurved teeth. The visual system is reduced; however, they can perceive sounds and vibrations from the substrate and have an accurate chemical sense. Most species are oviparous with a low number of eggs per litter and the sexual cycle is usually synchronized with the hot and rainy season; but other aspects related to the reproductive behavior of species are still unknown. They exhibit behavioral thermoregulation and microhabitat selection with temperatures more favorable to their activities, performing vertical migrations in the soil according to the environmental temperature and seasons. Soil types and soil water content seem to affect the spatial distribution of Amphisbaenia, but this relationship needs to be better studied...

Amphisbaenia: adaptações para o modo de vida fossorial / Amphisbaenia: adaptations to the fossorial lifestyle

Amphisbaenia são répteis fossoriais, que vivem em sistemas de túneis construídos por eles mesmos. Atualmente, são descritas 195 espécies recentes. O objetivo deste estudo foi reunir informações bibliográficas sobre aspectos de sua morfologia, fisiologia e comportamento relacionando-as ao hábito fossorial. O principal instrumento de escavação dos anfisbênios é a cabeça, cuja morfologia está relacionada com a maneira como a escavação é realizada. Assim, nas espécies com a cabeça arredondada o mecanismo de escavação é generalizado e nas espécies com a cabeça em forma-de-pá, de espátula ou com uma quilha vertical é especializado. O crânio é resistente, formado por placas ósseas rígidas, que devem suportar as investidas da cabeça. O corpo é alongado e cilíndrico desprovido de membros, na maioria, e formado por anéis tegumentares, importantes no deslocamento retilíneo do corpo para a frente e para trás, dentro dos túneis. O alongamento do corpo é refletido nos órgãos internos que são, em sua maioria, alongados; os órgãos pares tendem a sofrer redução ou deslocamento unilateral. Como estratégias de defesa utilizam-se da autotomia caudal, exibição da cauda ou salto de fuga. São predadores que se alimentam, normalmente, de insetos e suas larvas, apreendidos por mandíbulas potentes, dentes fortes e recurvados. O sistema visual é reduzido, no entanto, são capazes de perceber sons e vibrações oriundas do substrato, e possuem um acurado senso químico. A maioria das espécies é ovípara com um baixo número de ovos por ninhada e o ciclo sexual é geralmente sazonal, sincronizado com a estação quente e chuvosa, mas outros aspectos relacionados ao comportamento reprodutivo das espécies ainda são desconhecidos. Exibem termorregulação comportamental e selecionam micro-habitat com temperaturas mais favoráveis às suas atividades, realizando migrações verticais no solo, de acordo com a temperatura ambiental e estações do ano... (AU)

Amphisbaenia are fossorial reptiles, which live in tunnel systems built by themselves. Currently, 195 species are described. The objective of this study was to gather bibliographic information on aspects of their morphology, physiology and behavior related to the fossorial habit. The main digging tool of the amphisbaenians is the head, whose morphology is related to the way excavation is carried out. In round-headed species, the mechanism is generalized, and in species with a paddle-shaped head, a spatula or a vertical keel, is specialized. The skull is sturdy, consisting of rigid bony plates, which must support the head thrust. The body is elongated and cylindrical, devoid of limbs, mostly formed by integumentary rings, important in the rectilinear displacement of the body back and forth within the tunnels. The elongation of the body is reflected in the internal organs which are, for the most part, elongated; the paired organs tend to undergo unilateral reduction or displacement. As a defense strategy they use caudal autotomy, tail exhibit or escape jump. They are predators that normally feed on insects and their larvae, caught by powerful jaws, strong recurved teeth. The visual system is reduced; however, they can perceive sounds and vibrations from the substrate and have an accurate chemical sense. Most species are oviparous with a low number of eggs per litter and the sexual cycle is usually synchronized with the hot and rainy season; but other aspects related to the reproductive behavior of species are still unknown. They exhibit behavioral thermoregulation and microhabitat selection with temperatures more favorable to their activities, performing vertical migrations in the soil according to the environmental temperature and seasons. Soil types and soil water content seem to affect the spatial distribution of Amphisbaenia, but this relationship needs to be better studied...(AU)