Pterodactyloid Pterosaur Research Articles

Pterosaur tracks from the Upper Cretaceous (Cenomanian) Candeleros Formation of northwestern Patagonia, Argentina: Ichnotaxonomic and palaeoecological perspectives from Gondwana

New pterosaur tracks from the Cenomanian Candeleros Formation (Neuquén Basin) have been discovered in the Aguada de Tuco locality, northwestern Patagonia, Argentina. Preserved in medium-grained sandstones originating from alluvial deposits, these tracks include both isolated manus and pes impressions. The manus tracks are tridactyl and display a marked asymmetry, while pes tracks exhibit three-digit impressions and a subrectangular to subtriangular shape. The absence of a clearly defined trackway, coupled with the limited preservation quality of the documented pes tracks and distinctions from known pterosaur ichnotaxa, prompted the provisional assignment of these tracks to aff. Pteraichnus isp. They also exhibit a different morphology from previously recorded tracks within the same unit, thus contributing to a greater morphological variability of pterosaur tracks for the Candeleros Formation. Additionally, these tracks are found in association with narrow furrows interpreted as traces left by pterosaur manus and pes claws. Considering the shape and preservation of these tracks and the fragmentary record of pterosaurs from the Neuquén Basin, it is possible to attribute the producers to pterodactyloid pterosaurs. Moreover, the observed variability in manus track size, all sharing a similar morphology, suggests having been produced by individuals of different ages rather than different species of pterodactyloid pterosaurs. This study significantly contributes to our understanding of the pterosaur track record from Gondwana and the Cenomanian worldwide.

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.

The makers of Rhamphichnus ispp. reinterpreted as lepidosaurian and crocodilian, not pterosaurian

Three ichnospecies of the Late Jurassic trace fossil genus Rhamphichnus were first described and interpreted as the walking tracks of non-pterodactyloid pterosaurs like Rhamphorhynchus. This despite not resembling any previously identified pterosaur tracks and having a morphology unmatched by pterosaur skeletal elements. To fit the pterosaurian model, elongated imprints of R. pereiraensis and R. lafaurii, displaying four or five digit impressions were interpreted as manus prints, while shorter, five-digit prints were interpreted as imprints made by pedes with dislocated metatarsals and disarticulated phalanges. Comparison of published images and descriptions of Rhamphichnus ispp. to skeletal elements of six contemporaneous non-pterodactyloid taxa, skeletons and tracks from pterodactyloid pterosaurs, and modern and ancient lepidosaurs and crocodilians suggests an alternative interpretation. R. crayssacensis closely resembles crocodilian (Crocodylopodus (Sustenodactylus) isp.) and crocodylomorph (Batrachopus isp.) tracks; its holotype trackway was found 50 cm away from and parallel to a crocodilian swimming trackway with the same sized feet, possibly made by the same individual. R. pereiraensis and R. lafaurii strongly resemble lepidosaurian tracks and match the size and morphology of contemporary rhynchocephalians. Prints originally interpreted as manual and pedal in R. pereiraensis and R. lafaurii are reinterpreted and transposed in light of new data from pterosaurian, lepidosaurian, and crocodilian tracks and anatomy. Identification of fossil trackmakers depends on comparisons of a wide range of candidate taxa and elimination of those that cannot be considered further. With this reinterpretation of Rhamphichnus, there are no non-pterodactyloid pterosaurian tracks yet identified in the fossil record.

A new pterodactyloid pterosaur with a unique filter-feeding apparatus from the Late Jurassic of Germany

A new long-legged, spatula-beaked, filter-feeding pterodactyloid pterosaur from Upper Jurassic plattenkalk limestones at Wattendorf, Bavaria, Southern Germany, is remarkable for its completeness, unusual dentition and hints of the preservation of soft tissues, including wing membranes. The fully articulated specimen displays both jaws each side with over one hundred sub-parallel-sided teeth with a small, slightly hooked expansion at the crown tip. There are at least 480 teeth in total. The tip of the rostrum widens to a spatula-like, laterally concave structure with teeth only along its lateral margins. The straight anterior margin is devoid of teeth allowing plankton-rich water to stream in, while the teeth interdigitate forming a fine mesh trap. A slightly up swept rostrum assisted filtering by probable pulsating movements of the long neck, while wading or swimming through shallow water.

Note on new pterosaur remains (Archosauria: Pterodactyloidea) from Cerro La Isla, Atacama region, northern Chile

In this study, new isolated fragmentary pterosaur bones are described from Lower Cretaceous outcrops exposed at Cerro La Isla, a site located approximately 95 km east of Copiapó city, Atacama region, northern Chile. The material consists of a jaw fragment with broken teeth, the caudal portion of a mid-cervical vertebra and the distal portion of a femur. Based on their morphology, the jaw and cervical fragments are assigned to Ctenochasmatidae, a group of pterodactyloid pterosaurs that has been previously reported from this locality, while the femur lacks diagnostic characters that would allow its referral to a more exclusive taxon than Pterodactyloidea indet. This new material confirms the previously proposed presence of ctenochasmatid pterosaurs in the Cretaceous outcrops of Cerro La Isla, and increases the diversity of their skeletal elements discovered at the site.

The ontogenetic growth of Anhangueridae (Pterosauria, Pterodactyloidea) premaxillary crests as revealed by a crestless Anhanguera specimen

ABSTRACT The Anhangueridae are a clade of toothed pterodactyloid pterosaurs, known from their characteristic anteriorly expanded premaxillae and conspicuous rostral sagittal premaxillary and dentary crests. Most known anhanguerids come from the Lower Cretaceous Romualdo Formation within the Araripe Basin of northeast Brazil. With four currently valid genera and several specimens referred to the clade, anhanguerids are the most abundant and diverse tetrapod group in the Romualdo Formation. However, some studies suggest this diversity may be overestimated, as many taxa have been diagnosed based on subtle differences in their premaxillary crests, a structure argued to be either ontogenetically variable or sexually dimorphic. Here we describe an anterior fragment of a gracile pterosaur rostrum that possesses the single diagnostic feature of Anhanguera (fifth and sixth pairs of dental alveoli smaller than the fourth and seventh), but lacks a sagittal crest. The affinities of the new fossil among other toothed pterosaurs were tested through both cladistic and geometric morphometric approaches, which allow referral of the new specimen to Anhanguera. The absence of a crest in the new specimen of Anhanguera suggests that this structure varies in terms of ontogeny and/or sex, and that perhaps it was influenced by sexual selection.

The wandering jaws of Istiodactylus latidens (Pterosauria, Istiodactylidae)

A new specimen of the Early Cretaceous pterodactyloid pterosaur Istiodactylus latidens is described. This specimen in the Moscow Vernadsky State Geological Museum represents the associated anterior ends of the rostrum and mandibular symphysis but lacks collection data. It likely comes from the Barremian-Aptian Vectis Formation of southern England based on a pollen analysis of the matrix sample. This specimen could represent the missing jaws of the holotype of I. latidens. The specimen was studied using computer microtomography. It has an isodont dentition consisting of large lancet-like interlocking teeth, a mandibular odontoid process, and a palatal ridge. The palatal ridge, known previously for some istiodactylid taxa, is reported here for the first time for Istiodactylus.

New toothed pterosaurs (Pterosauria: Ornithocheiridae) from the middle Cretaceous Kem Kem beds of Morocco and implications for pterosaur palaeobiogeography and diversity

Pterodactyloid pterosaurs underwent a diversification in the Late Jurassic and Early Cretaceous, followed by a major turnover event in the mid-Cretaceous, when ornithocheirids and basal azhdarchoids were replaced by pteranodontids, nyctosaurids and azhdarchids in the latest Cretaceous. However, precise patterns of turnover are obscured by the incompleteness of the pterosaur fossil record. Fossils from the middle Cretaceous Kem Kem beds of Morocco (?Albian –Cenomanian) have helped shed light on the diversity of pterosaurs from this time and provide a window into the diversity of a continental pterosaur assemblage from this critical transitional period. Two toothed pterosaurs, the ornithocheirids Siroccopteryx moroccensis and Coloborhynchus fluviferox, have been reported from the Kem Kem beds. Here, we report a partial mandible and two premaxillae representing three additional taxa of toothed pterosaurs. The mandibular symphysis closely resembles that of Anhanguera piscator from the Romualdo Member of the Santana Formation of Brazil in the arrangement and spacing of the alveoli, the weak anterior upturn of the jaw, and the ventral crest. One premaxilla closely resembles that of the ornithocheirid Ornithocheirus simus from the Cambridge Greensand Formation of eastern England. A second premaxilla is referred to Coloborhynchus, bearing similarities to C. clavirostris from the Hastings Group of southern England, and C. fluviferox from the Kem Kem beds of Morocco. In total, the Kem Kem pterosaur fauna includes at least nine species, of which five are ornithocheirids. The Kem Kem assemblage supports the hypothesis that toothed pterosaurs remained diverse during the mid Cretaceous before disappearing from post-Cenomanian strata.

A new ?chaoyangopterid (Pterosauria: Pterodactyloidea) from the Cretaceous Kem Kem beds of southern Morocco

A new genus and species of edentulous pterodactyloid pterosaur with a distinctive partial rostrum from the mid-Cretaceous (?Albian/Cenomanian) Kem Kem beds of southeast Morocco is described. The taxon is assigned to Chaoyangopteridae based upon its edentulous jaws, elongate rostrum and slightly concave dorsal outline. The rostral cross-section is rounded dorsally and concave on the occlusal surface. The lateral margins are gently convex dorsally becoming slightly wider toward the occlusal border, and a row of small lateral foramina parallel to the dorsal margin determines it as a taxon distinct from other chaoyangopterids. Apatorhamphus gyrostega gen et sp. nov. is a pterosaur of medium to large size (wingspan likely somewhere between ~3 m and ~7 m). This new species brings the number of named Kem Kem azhdarchoids to three, and the number of named Kem Kem pterosaurs to five, indicating a high pterosaur diversity for the Kem Kem beds.

The first non-pterodactyloid pterosaurian trackways and the terrestrial ability of non-pterodactyloid pterosaurs

New discoveries on the ichnological site known as “the Pterosaur Beach of Crayssac” (lower Tithonian, Upper Jurassic; south-western France) answer the question of terrestrial capabilities of non-pterodactyloid pterosaurs. If the terrestrial type of locomotion of pterodactyloid pterosaurs has been solved from ichnological evidence for more than twenty years, no tracks and trackways referable to non-pterodactyloid pterosaurs have ever been described. Thus, the debate on terrestrial capabilities of these non-pterodactyloids was based on morpho-functional studies, with the main conclusion that those pterosaurs were arboreal dwellers and bad walkers. Six trackways referable to three non-pterodactyloid new ichnotaxa, maybe closely related to Rhamphorhynchidae, are described in this work. Their study leads to the conclusion that grounded non-pterodatyloids, at least during the Late Jurassic, were quadrupedal with digitigrade manus and plantigrade to digitigrade pes. They were clearly good walkers, even if hindlimbs are supposed to be hampered by the uropatagium, what could have constrained the terrestrial agility of these animals. Thus, from ichnological evidence and contrary to the current hypotheses, non-pterodactyloid pterosaurs seem to have been good walkers even though their trackways are very rare or unidentified to date. This rarity could be due to behaviour rather than to functional capacities, many non-pterodactyloids being considered both littoral fishers and arboreal or cliff dwellers. However, the concept of non-pterodactyloid “good climbers and bad walkers” has to be modified to “good climbers and rare walkers”, unless many non-pterodactyloid ichnites have yet to be discovered.

Additional evidence for very large wing-span pterosaurs in the Wessex Formation (Early Cretaceous, Barremian) of southern England

A partial distal left metacarpal IV of a pterodactyloid pterosaur is notable for its size. The specimen, from the Early Cretaceous (Barremian) Wessex Formation exposed on the southwest coast of the Isle of Wight, southern England is identified as an ornithocheirid, perhaps close to the Ornithocheirus, Coloborhynchus, Caulkicephalus, Anhanguera complex. A morphometric analysis suggests an original wing span of approximately 5.6 m. With an early Barremian age, this pterosaur would have been a giant for its time.

On a new crested pterodactyloid from the Early Cretaceous of the Iberian Peninsula and the radiation of the clade Anhangueria

The pterosaur record from the Iberian Peninsula is mostly scarce and undefined, but in the last few years some new taxa have been described from different Lower Cretaceous sites of Spain. Here we describe a new genus and species of toothed pterodactyloid pterosaur from the Barremian of the Iberian Peninsula, Iberodactylus andreui gen. et sp. nov., that shows a close and rather unexpected relationship with Hamipterus tianshanensis from China. A review of the phylogenetic relationships of the Anhangueria reveals a new family of pterodactyloid pterosaurs, the Hamipteridae fam. nov. being recovered as sister-group of the Anhangueridae. This latter clade can be in turn divided into the new clades Anhanguerinae and Coloborhynchinae. The close relationships of Iberodactylus and Hamipterus shows an interesting palaeobiogeographical correlation between the Chinese and Iberian pterosaur faunas during the Barremian (Lower Cretaceous). The discovery of Iberodactylus strongly suggests that the clade Anhangueria has clear ancestral ties in eastern Laurasia.

First Pterosaur Post-Cranial Remains from the Lower Cretaceous Lohan Cura Formation (Albian) of Patagonia, Argentina

In this contribution, we present the first pterosaur post-cranial bone from the Lohan Cura Formation (Albian) of the Cerro de los Leones locality (Picun Leufu, Neuquen Province). The material is an incomplete left ulna, preserved in three dimensions, and composed of the proximal epiphysis and part of the diaphysis. The element shares several affinities with derived pterodactyloid pterosaurs, such as a diaphysis with a sub-oval cross-section, thin bone walls, pneumatic foramina in the dorsal surface of the proximal epiphysis and between the cotyles, and wingspan reconstruction indicating a medium-size specimen. An analysis of the microstructure allowed us to evaluate the ontogenetic stage of the specimen. The thin-section from the mid-shaft shows a wide and sub-circular medullary cavity, encircled by a thin cortical bone ring. In the innermost cortex, secondary lamellar bone forms a distinct and avascular endosteal layer, while the cortical layer is dominated by a well vascularized primary bone with coarse parallel fibers, as in other pterodactyloids. The presence of an avascular endosteal lamellar layer, an unremodeled cortical layer dominated by parallel-fibered bone, and a well ossified proximal epiphysis suggest that the specimen was an advanced juvenile or sub-adult with active-growth at the time of death. Considering the limited pterosaurian fossil record of Argentina, the new pterosaur specimen not only contributes to the reconstruction of the paleoecosystem of the Lohan Cura Formation in the central Neuquen Basin, but also improves our knowledge on the pterosaur taxonomic diversity during the Early Cretaceous of Patagonia.

Pterodactyloid pterosaur bones from Cretaceous deposits of the Antarctic Peninsula.

Fossil vertebrates from Antarctica are considerably rare, hampering our understanding of the evolutionary history of the biota from that continent. For several austral summers, the PALEOANTAR project has been carrying out fieldwork in the Antarctic Peninsula in search for fossils, particularly Cretaceous vertebrates. Among the specimens recovered so far are two bones referable to Pterosauria, more specifically to the Pterodacyloidea, the first volant reptiles from Antarctica to be fully described. MN 7800-V (part and counterpart) was recovered from a moraine at the Abernathy Flats (Santa Marta Formation, Lachman Crags Member, Santonian-Campanian) on James Ross Island. It is interpreted as the distal articulation of a first phalanx of the wing finger, representing an animal with an estimated wingspan between 3 and 4 m. The second specimen (MN 7801-V) comes from Vega Island (Snow Hill Island Formation, Maastrichtian) and is identified as a wing metacarpal IV of an animal with an estimated wingspan from 4 to 5 m. These occurrences show that pterodactyloids inhabited the Antarctic Peninsula at least during the Upper Cretaceous and demonstrate that large pterosaurs were widespread through all parts of the planet during that period.

Rediscovery of the Tagragra Tracksite (Maastrichtian, Agadir, Morocco): Agadirichnus elegans Ambroggi and Lapparent 1954 is Pterosaurian Ichnotaxon

ABSTRACTDiscovered in 1954 by Ambroggi and Lapparent, the Tagragra tracksite (Maastrichtian, Agadir, Morocco) yielded tracks of theropod dinosaurs, birds and enigmatic forms tentatively attributed to Lacertilia under the name Agadirichnus elegans. The original specimens are today considered to be lost, and the status of A. elegans has been questioned, even though these footprints can retrospectively be referred to pterodactyloid pterosaur tracks. In order to discuss the status of these foot prints, the historical site has been actively sought and recently rediscovered by one of us (MdD). New material confirms the presence of pterodactyloid footprints, with two morphotypes, in two different facies, respectively associated with bird and theropod tracks. Morphotype I is tentatively conferred to Pteraichnus Stokes 1957, which extends the stratigraphical distribution of this ichnotaxon to the Maastrichtian. Morphotype II corresponds to the original ichnospecies A. elegans Ambroggi and Lapparent 1954, which is here reassessed as a valid ichnotaxon, with the designation of a neotype. Thus, A. elegans Ambroggi and Lapparent 1954 is historically the first pterosaurian ichnotaxon ever described.

Systematic reassessment of the first Jurassic pterosaur from Thailand

Abstract A pterosaur humerus (PRC 64) from the Upper Jurassic of Thailand was initially assigned to the Azhdarchoidea, an important clade of edentulous Cretaceous pterodactyloid pterosaurs. Here it is reassigned, on the basis of morphological comparisons and a phylogenetic analysis, to the Rhamphorhynchidae, a widely distributed clade of small to medium-sized seemingly piscivorous basal pterosaurs. This record extends the geographical range of rhamphorhynchids and confirms recent findings that these pterosaurs inhabited continental as well as marginal marine ecosystems.

A large pterodactyloid pterosaur from the Upper Jurassic of Liuhuanggou, Xinjiang, People's Republic of China

A large pterodactyloid pterosaur from the Upper Jurassic of Liuhuanggou, Xinjiang, People's Republic of China

A large pterodactyloid pterosaur from the Late Cretaceous Ferron Sandstone of Utah

Abstract Three associated incomplete wing bones of a large pterodactyloid pterosaur from the Ferron Sandstone Member of the Mancos Shale Formation of Utah are described. Based on the morphology of the bones’ articular ends, the specimen is referred to the Pteranodontoidea. Associated ammonites indicate that the specimen's age is Middle Turonian, so it adds to the sparse worldwide record of Turonian pterosaurs. The record of pteranodontoid pterosaurs in the Western Interior Seaway of North America is reviewed, and it is suggested that pteranodontoids were not diverse.

A new pterosaur specimen from the Upper Tunbridge Wells Sand Formation (Cretaceous, Valanginian) of southern England and a review of Lonchodectes sagittirostris (Owen 1874)

Abstract A specimen of a pterodactyloid pterosaur from the Upper Tunbridge Wells Sand Formation (Early Cretaceous, Valanginian) of Bexhill, East Sussex, southern England is described. It comprises a small fragment of jaw with teeth, a partial vertebral column and associated incomplete wing bones. The juxtaposition of the bones suggests that the specimen was originally more complete and articulated. Its precise phylogenetic relationships are uncertain but it represents an indeterminate lonchodectid with affinities to Lonchodectes sagittirostris (Owen 1874) which is reviewed here, and may belong in Lonchodraco Rodrigues & Kellner 2013. This specimen is only the third record of pterosaurs from this formation.

Topotype specimens probably attributable to the giant azhdarchid pterosaur Arambourgiania philadelphiae (Arambourg 1959)

Abstract Six specimens accessioned to the Bavarian State Collection for Palaeontology and Geology in Munich, Germany, in 1966 are identified as coming from a gigantic pterodactyloid pterosaur. The previously undescribed material was obtained in 1955 by Jean Otto Haas and compares favourably in size with the type specimen of the Late Cretaceous (Maastrichtian) azhdarchid pterosaur Arambourgiania philadelphiae (Arambourg 1959) from the same locality/region. The material represents fragments of two cervical vertebrae, a neural arch, a left femur, a ?radius, and a metacarpal IV and bones of problematic identity, and does not duplicate the type material of Arambourgiania . The timing of its collection and its locality of Ruseifa, Jordan suggest it might pertain to the same individual as the holotype.