Forfexopterus jeholensis: a new Archaeopterodactyloid Pterosaur From Cretaceous China

A new archaeopterodactyloid pterosaur from the Jiufotang Formation of western Liaoning, China, with a comparison of sterna in Pterodactylomorpha

Authors:

Jiang et al

Abstract:

Eleven species of archaeopterodactyloid pterosaurs have been reported in China, mostly from the Yixian Formation of western Liaoning. The first uncontroversial archaeopterodactyloid from the Jiufotang Formation is described here. A new genus and species, Forfexopterus jeholensis, is erected on the basis of a unique combination of characters and one autapomorphy: the first wing phalanx is shorter than the second, but longer than the third. The sternum of Forfexopterus is nearly complete and provides the first incontrovertible evidence about the position of sternocoracoid articulations in the Archaeopterodactyloidea. A preliminary geometric morphometric analysis of sterna was carried out with data from 17 species of Pterodactylomorpha. The results document the variation in the shape of the sternum, including the length of the cristospine, the shapes of the lateral, posterior, and anterior margins, and the constriction and expansion of the cristospine. These characters can be used to compare sterna in different pterosaur taxa.

Gladocephaloideus: a new Ctenochasmatoid Pterosaur From Cretaceous CHina

New Material of the Pterosaur Gladocephaloideus Lü et al., 2012 from the Early Cretaceous of Liaoning Province, China, with Comments on Its Systematic Position

Authors:

Lü et al

Abstract:

Although there are nine genera of ctenochasmatoids reported from the Jehol Biota, at present each is known from a specimen that has either a skull or a relatively complete postcranial skeleton. A nearly complete juvenile specimen of Gladocephaloideus from the Lower Cretaceous Jiufotang Formation of Sihedang, Lingyuan of Liaoning Province is the most complete ctenochasmatoid preserved to date with a skull and postcranial skeleton. Based on the holotype (IG-CAGS 08–07) and the nearly complete new specimen (JPM 2014–004), the diagnosis of Gladocephaloideus is amended: approximately 50 teeth in total with sharp tips; small nasoantorbital opening, occupying approximately 13% of total skull length; ratio of prenarial rostrum length to skull length approximately 0.63; deep groove along the mid-line of the mandibular symphysis; length to width ratio of the longest cervical vertebra = 4.1; ratio of femur length to tibia length = 0.61; tibia as long as the wing-phalange 1. Phylogenetic analysis recovers Gladocephaloideus within the clade Ctenochasmatidae. Gladocephaloideus has a closer relationship to the Chinese Pterofiltrus rather than to other ctenochasmatid pterosaurs. Microstructure of limb bones implies that JPM 2014–004 represents an early juvenile of Gladocephaloideus jingangshanensis, and that the type specimen is not a fully grown specimen either. We assume that the holotype may equate to the late juvenile or sub-adult developmental stage of Gladocephaloideus.

Anisian Triassic Dinosauriform Asilisaurus kongwe Just Complicated Dinosauriform Ontogeny

The femoral ontogeny and long bone histology of the Middle Triassic (?late Anisian) dinosauriform Asilisaurus kongwe and implications for the growth of early dinosaurs

Authors:

Griffin et al

Abstract:

The ontogeny of early-diverging dinosauromorphs is poorly understood because few ontogenetic series from the same species-level taxon are known and what is available has not been extensively documented. The large numbers of skeletal elements of the silesaurid Asilisaurus kongwe recently recovered from Tanzania provide an opportunity to examine the ontogenetic trajectory of the earliest known member of Ornithodira and one of the closest relatives to Dinosauria. We examined the ontogeny of the femur and the histology of a series of long bone elements. We observed bone scar variation in a series of femora (n = 27) of different lengths (73.8–177.2 mm). We hypothesize that most femora follow a similar developmental trajectory; however, we observed sequence polymorphism in the order of appearance and shape of bone scars, and we quantified this polymorphism using ontogenetic sequence analysis (OSA). Additionally, five femora, three tibiae, a fibula, and a humerus were thin-sectioned to examine osteological tissues. No lines of arrested growth (LAGs) are present in any specimen, and there is little histological information about the ontogenetic stage of femora, although none have slowed or ceased growth. The woven-fibered bone present in the cortex of elements sectioned is similar to that of the earliest dinosaurs. This sequence polymorphism provides an alternate hypothesis for the robust/gracile dichotomy found in early dinosaurs often interpreted as sexual dimorphism. The shared femoral features found in Asilisaurus and early dinosaurs suggest that this ontogenetic pattern is plesiomorphic for Dinosauria, and that size is a poor predictor of maturity in early dinosauriforms.

Cimoliopterus dunni: a new Toothed Pterosaur From Cenomanian Cretaceous Texas

First North American occurrence of the toothed pteranodontoid pterosaur Cimoliopterus

Author:

Myers

Abstract:

A new pterosaur species, Cimoliopterus dunni, sp. nov., is described based on a partial rostrum from the upper Cenomanian Britton Formation in the Eagle Ford Group of north-central Texas. The holotype preserves alveoli for a minimum of 26 upper teeth and bears a thin premaxillary crest that begins above the fourth pair of alveoli. The rostrum, characterized by a slight lateral flare, lacks the pronounced lateral expansion found in ornithocheirids and anhanguerids. The tip of the snout is small and blunt, and the anterior face of the rostrum is oriented posteroventrally, forming an approximately 45° angle with the anterior portion of the palate. The anteroventrally oriented first pair of alveoli is directed more ventrally than anteriorly. Phylogenetic analysis suggests that Cimoliopterus dunni and Cimoliopterus cuvieri, from the Cenomanian Grey Chalk Subgroup in Kent, England, are basal pteranodontoids that are closely related to Aetodactylus halli from the middle Cenomanian Tarrant Formation of north Texas. Cimoliopterus dunni marks only the second known occurrence of Cimoliopterus, extending its geographic range from Europe to North America. In conjunction with Coloborhynchus wadleighi from the upper Albian Pawpaw Formation, Cimoliopterus dunni provides unambiguous evidence of biogeographic linkages between the pterosaur faunas of North America and Europe in the middle Cretaceous.

The Form of Pterosaur Bellubrunnus' Wingtips Suggests a Unique Flight Profile

The wingtips of the pterosaurs: Anatomy, aeronautical function and ecological implications

Authors:

Hone et al

Abstract:

The leading edge and shape of the pterosaur wing is constrained by the skeleton. Although it has long been known that at least some pterosaurs had posteriorly curved distal wing phalanges, affecting the shape of the wingtip, this has been little studied despite that this may have profound effects on flight performance. Here we examine the evidence for curved wingtips in pterosaurs and evaluate the possible aerodynamic and aeronautical effects. Curved wingtips are shown to be common in both pterosaurs likely to have inhabited terrestrial environments, and those which were strongly pelagic. The recently described genus Bellubrunnus provides new anatomical novelty for pterosaurs having anteriorly directed wingtips and thus likely had a different flight profile to all previously known pterosaurs.

Pterosaurs had two Ovaries, Seem to Lack Medullary Bone

Eggshell and Histology Provide Insight on the Life History of a Pterosaur with Two Functional Ovaries

Authors:

Wang et al

Abstract:

The counterpart of a previously described non-pterodactyloid pterosaur with an egg revealed the presence of a second egg inside the body cavity of this gravid female. It clearly shows that pterosaurs had two functional oviducts and demonstrates that the reduction of one oviduct was not a prerequisite for developing powered flight, at least in this group. Compositional analysis of one egg suggests the lack of a hard external layer of calcium carbonate. Histological sections of one femur lack medullary bone and further demonstrate that this pterosaur reached reproductive maturity before skeletal maturity. This study shows that pterosaurs laid eggs even smaller than previously thought and had a reproductive strategy more similar to basal reptiles than to birds. Whether pterosaurs were highly precocial or needed parental care is still open to debate.

Pterosaur -opolcalypse!

Comments on Triassic pterosaurs with discussion about ontogeny and description of new taxa

Author:

Kellner

Abstract:

Eudimorphodon ranzii was the first Triassic pterosaur to be described and several specimens have been referred to this taxon mainly based on the presence of multicuspid teeth. Since this dental feature has been observed in several other pterosaurs, the revision of some specimens assigned to Eudimorphodon shows that they represent new taxa as follows: Arcticodactylus cromptonellus (comb. nov.), Austriadraco dallavecchiai (gen. et sp. nov.) and Bergamodactylus wildi (gen. et sp. nov.). A preliminary analysis of pterosaur ontogeny resulted in the recognition of six distinct ontogenetic stages (OS1-6). According to this classification, the holotype of Arcticodactylus cromptonellus has reached OS2, and although being ontogenetically much younger than others, the conspicuous anatomical differences lead to its exclusion from Eudimorphodon. The holotypes of Austriadraco dallavecchiai, Bergamodactylus wildi and Carniadactylus rosenfeldi have reached at least OS5, which demonstrates that the anatomical differences among them cannot be explained by ontogeny. Moreover, Bergamodactylus wildi reaches about 60% of the maximized wingspan of Carniadactylus rosenfeldi and further concurs that these specimens collected in distinct Triassic Islands of Europe are not conspecific. The present study increases the diversity of Triassic flying reptiles and further pushes the origins of this clade back to at least the Middle Triassic.

A Short Necked Azhdarchid Pterosaur From Maastrichtian Cretaceous Romania

A Medium-Sized Robust-Necked Azhdarchid Pterosaur (Pterodactyloidea: Azhdarchidae) from the Maastrichtian of Pui (Haţeg Basin, Transylvania, Romania)

Authors:

Vremir et al

Abstract:

We describe a pterosaurian cervical vertebra collected from Maastrichtian sediments at the Pui locality in the Haţeg Basin, Romania. This specimen, a medium-sized, robust fourth cervical, is distinctive in morphology and represents a new, as yet unrecognized, azhdarchid pterosaur size class within the Haţeg Island fauna: it most likely belongs to a new taxon which we opt not to name here. The vertebra is referred to Azhdarchidae based on clearly preserved diagnostic features characteristic of this group and differs in proportions and anatomical details from the recently named azhdarchid Eurazhdarcho langendorfensis Vremir et al., 2013a, from the Sebeş region of the Transylvanian basin. We take issue with claims that all Maastrichtian Romanian azhdarchids (and other penecontemporaneous azhdarchids and azhdarchoids) should be uncritically assumed to be synonymous: it ignores anatomical characters that allow the specimens concerned to be differentiated and is based on an erroneous “one stratum, one species” philosophy contradicted by empirical data from other azhdarchoid assemblages. It has been suggested that the absence of small to medium-sized pterosaurs in Upper Cretaceous sediments is indicative of an evolutionary trend. However, evidence from the Haţeg Island fauna may indicate instead that smaller-sized pterosaurs were indeed present in this interval but remain underrepresented due to rare preservation and collection.

Orientognathus chaoyngensis: a new Rhamphorhynchid Pterosaur From Upper Jurassic China

A new rhamphorhynchid pterosaur (Pterosauria) from Jurassic deposits of Liaoning Province, China

Authors:

Lü et al

Abstract:

Compared to pterosaurs from the Early Cretaceous from China, Late Jurassic pterosaurs are relatively rare. A new rhamphorhynchid pterosaur, Orientognathus chaoyngensis gen. et sp. nov., is erected based on an incomplete skeleton from the Upper Jurassic Tuchengzi Formation of Chaoyang, Liaoning Province, China. It is identified by the following characters: the toothless tip of the lower jaw is slightly pointed; the length ratio of wing metacarpal to humerus is 0.38, the ulna is shorter than each wing phalanx and the tibia is nearly equal to femur in length. A phylogenetic analysis recovers Orientognathus chaoyngensis as a rhamphorhynchid pterosaur. Orientognathus chaoyngensis is perhaps the youngest Jurassic pterosaur from western Liaoning Province of China.

Contrarian View: Did Pterosaurs NOT Breathe Like Birds?

Breathing in a box: Constraints on lung ventilation in giant pterosaurs

Authors:

Giest et al

Abstract:

Pterosaurs were the first vertebrates to achieve active flight, with some derived forms reaching enormous size. Accumulating fossil evidence confirms earlier indications that selection for large size in these flying forms resulted in a light, yet strong skeleton characterized by fusion of many bones of the trunk. However, this process also added mechanical constraints on the mobility of the thorax of large pterosaurs that likely limited the options available for lung ventilation. We present an alternative hypothesis to recent suggestions of an avian-like mechanism of costosternal pumping as the primary means of aspiration. An analysis of the joints among the vertebrae, ribs, sternum, and pectoral girdle of large pterosaurs indicates limited mobility of the ribcage and sternum. Comparisons with modes of lung ventilation in extant amniotes suggests that the stiffened thorax, coupled with mobile gastralia and prepubic bones, may be most consistent with an extracostal mechanism for lung ventilation in large pterodactyloids, perhaps similar to a crocodile-like visceral displacement system.

Two bits.  I thought crocs did breathe like birds?  And given iguanas and monitors are supposed to as well, that strikes me as the likelihood is the bird-breathing scheme is basal to diapsids.  I am waiting to see what Mark and Darren state about this...

Alanqa saharica: an Albanian/Campanian Cretaceous Azhdarchid Pterosaur With an Unusual Jaw Modification

An unusual modification of the jaws in cf. Alanqa, a mid-Cretaceous azhdarchid pterosaur from the Kem Kem beds of Morocco

Authors:

Martill et al

Abstract:

A jaw bone attributed to the mid-Cretaceous azhdarchid pterosaur Alanqa saharica Ibrahim et al., 2010 is described. The new specimen from the Kem Kem beds of south eastern Morocco is unusual for the presence of expanded rostral bones that protrude above the occlusal surface of the jaws. The function of this unusual osteological modification is uncertain, but it is considered likely that it served a role in food processing, or perhaps jaw stability.

Daohugoupterus delicatus: a new Pterosaur From Middle Jurassic Inner Mongolia

Short note on a non-pterodactyloid pterosaur from Upper Jurassic deposits of Inner Mongolia, China

Authors:

Cheng et al

Abstract:

Daohugou is an important locality of the Jurassic Yanliao Biota, where only two pterosaurs have been described so far (Jeholopterus and Pterorhynchus). Here we report a new genus and species, Daohugoupterus delicatus gen. et sp. nov. (IVPP V12537), from this region, consisting of a partial skeleton with soft tissue. The skull is laterally compressed, differing from Jeholopterus. The antorbital fenestra is larger than in Pterorhynchus. The upper temporal fenestra is unusually small. The short cervical vertebrae bearing cervical ribs indicate that it is a non-pterodactyloid flying reptile. The sternal plate is triangular, being much wider than long. The deltopectoral crest of humerus is positioned proximally and does not extend further down the shaft, a typical feature of basal pterosaurs. Daohugoupterus also differs from the wukongopterids and scaphognathids from the Tiaojishan Formation at Linglongta, regarded to be about the same age as the Daohugou Bed. The new specimen increases the Jurassic non-pterodactyloid pterosaur diversity of the Yanliao Biota and is the smallest pterosaur from Daohugou area so far.

A New, Exquisite Anhanguera piscator (Pterosaur) Specimen From Aptian/Albian Cretaceous Brazil

The pterodactyloid pterosaur from the Lower Cretaceous of Brazil at the CosmoCaixa Science Museum (Barcelona, Spain)

Authors:

Dalla Vecchia et al

Abstract:

An apparently nearly complete and fairly well-articulated specimen of a large toothed pterosaur from the Lower Cretaceous of Brazil is exhibited at the CosmoCaixa – Museo de la Ciencia, Barcelona, Spain. The museum label refers it to Anhanguera piscator and reports a provenance from the Crato Formation. Its study shows that it is from the Romualdo Formation and is an assembled and composite specimen over 45% reconstructed. The original skeletal elements show no diagnostic feature of Anhanguera piscator, belong to non-tapejarid pterosaurs, and do not furnish further significative scientific information. Several mistakes were made in the reconstruction and assemblage of the skeleton and some elements do not follow the proportions of Anhanguera piscator. Care is suggested when describing pterosaur material from the Romualdo Formation prepared and sold by private fossil dealers in the absence of an adequate documentation on the original material and its preparation.

Anurognathus ammoni: an Anurognathid Pterosaur From Late Jurassic China

Short note on an anurognathid pterosaur with a long tail from the Upper Jurassic of China

Authors:

Jiang et al

Abstract:

Pterosaurs consist of an extinct group of flying reptiles that show short- and long-tailed species. Among those are the anurognathids whose phylogenetic position has been considered quite controversial. So far, there are about 10 described specimens from the Anurognathidae, from which only a few show the preservation of caudal elements. Here, we report a new anurognathid specimen (IVPP V16728) from Mutoudeng, Qinglong, Hebei, China that shows the most complete tail of this non-pterodactyloid clade. The preserved part of the tail has at least 20 caudal vertebrae, some showing extended chevrons and zygapophyses, which is a very primitive character within pterosaurs.

Medullary Bone-like Tissue in Found in Satonian Cretaceous Pterosaur Bakonydraco

Medullary bone-like tissue in the mandibular symphyses of a pterosaur suggests non-reproductive significance

Authors:

Prondvai et al

Abstract:

Medullary bone is a special bone tissue forming on the endosteal surface of the medullary cavity in the bones of female birds prior to and during egg-laying to serve as a calcium reservoir for building the hard eggshell. It has also been identified in non-avian dinosaurs, where its presence is considered as a reliable indicator of a sexually mature female. Here, we reveal that multiple mandibular symphyses of the azhdarchid pterosaur Bakonydraco galaczi possess a special bone tissue that shows all microanatomical, histological, and developmental characteristics of medullary bone, despite its unusual location. Its frequent occurrence in the sample renders a pathologic origin unlikely. Our findings as well as the extremely thin-shelled eggs of pterosaurs suggest that this medullary bone-like tissue probably had a non-reproductive role in these animals. Although the non-reproductive significance and the anatomical location of this medullary bone-like tissue in Bakonydraco suggest independent evolutionary appearance from dinosaurian medullary bone, a common origin and later diverging function and physiological regulation is an equally viable phylogenetic hypothesis.

Oh no They Didn't! Ikrandraco avatar: An Aptian Cretaceous Pterosaur From Aptian Cretaceous China

An Early Cretaceous pterosaur with an unusual mandibular crest from China and a potential novel feeding strategy

Authors:

Wang et al

Abstract:

The Aptian Jiufotang Formation of northeast China is a Konservat Lagerstätte particularly rich in pterosaurs, notably azhdarchoids. Here we describe a new genus and species of toothed pteranodontoid pterosaur, Ikrandraco avatar gen. et sp. nov., based on two laterally flattened specimens. Ikrandraco avatar is diagnosed by a suite of features, including a very low and elongate skull, strongly inclined quadrate, and a deep, blade-like bony mandibular crest with a hook-like process on its posterior edge, an unusual structure so far unique to this taxon. The particular skull shape hints at a distinct feeding habit for pterosaurs that potentially includes temporary skimming and an extensible skin acting as a throat pouch that was more developed than in any other pterosaur known so far. The presence of two other taxa of purported piscivorous pterosaurs in the Jiufotang Formation suggests distinct resource exploitation in this part of China during the Early Cretaceous.

Mark Whitton on Scleromochlus taylori: the Carnian Triassic Ornithodiran Archosaur Pretending to be a Gerbil

Go read and behold the awesomeness.

Caiuajara dobruskii: a Gregarious Upper Cretaceous Pterosaur Found in a Bonebed in Brazil

Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles

Authors:

Manzig et al

Abstract:

A pterosaur bone bed with at least 47 individuals (wing spans: 0.65–2.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (~115°) in juveniles to large and steep (~90°) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs.

Azhdarchid Pterosaur Fossil Found in Campanian Cretaceous Russia

A pterosaurian vertebra from the Upper Cretaceous of the Saratov Region

Authors:

Averianov et al

Abstract:

A dorsal vertebra referred to as Azhdarchidae indet. from the Rybushka Formation (Upper Cretaceous, Lower Campanian) of the Beloe Ozero locality in the Saratov Region is described. Its vertebral centrum has a hypapophysis and, at the base of the neural arch, there is a large pneumatic foramen. The vertebra possibly belongs to Volgadraco bogolubovi Averianov, Arkhangelskii et Pervushov, 2008, described from the Rybushka Formation of the Shirokii Karamysh 2 locality in the Saratov Region.

Thalassodromeus sebesensis: A Chronologically & Geographically Unexpected Maastrichtian Cretaceous Tapejarid Pterosaur

Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur

Authors:

Grellet-Tinner et al

Abstract:

We report here the first occurrence of a small pterosaur, Thalassodromeus sebesensis from the Maastrichtian Hateg Island. This new species with its significantly expanded premaxillary crest extends the known distribution of this genus from South America to Europe. Furthermore, this important discovery doubles the thalassadromine fossil record and demonstrates a 42 million years temporal displacement from its older Aptian Gondwanan congener Thalassodromeus sethi. Thalassodromeus sebesensis sp. nov. is diagnosed by an unusual expanded premaxillary crest and synapomorphies shared only with its Brazilian congener, T. sethi. Yet, the new specimen displays enough autapomorphic characters to erect a new thalassodromine species. The discovery of Thalassodromeus sebesensis in an exposure known for its diverse angiosperm assemblage lends more support to the tapejarid and flowering plants co-evolution. It also suggests this new small thalassadromine was a forest dweller, as such possibly not competing with the known giant azhdarchid pterosaurs on this island. Moreover, its presence in this insular ecosystem confirms once more the aberrant nature of the Late Cretaceous Hateg island-dwelling endemic fauna.