Taissa Rodrigues

Background
Anhanguerids comprise an important clade of pterosaurs, mostly known from dozens of three-dimensionally preserved specimens recovered from the Lower Cretaceous Romualdo Formation (northeastern Brazil). They are remarkably diverse in this sedimentary unit, with eight named species, six of them belonging to the genus Anhanguera. However, such diversity is likely overestimated, as these species have been historically diagnosed based on subtle differences, mainly based on the shape and position of the cranial crest. In spite of that, recently discovered pterosaur taxa represented by large numbers of individuals, including juveniles and adults, as well as presumed males and females, have crests of sizes and shapes that are either ontogenetically variable or sexually dimorphic.

Methods
We describe in detail the skull of one of the most complete specimens referred to Anhanguera, AMNH 22555, and use it as a case study to review the diversity of anhanguerids from the Romualdo Formation. In order to accomplish that, a geometric morphometric analysis was performed to assess size-dependent characters with respect to the premaxillary crest in the 12 most complete skulls bearing crests that are referred in, or related to, this clade, almost all of them analyzed first hand.

Results
Geometric morphometric regression of shape on centroid size was highly statistically significant (p = 0.0091) and showed that allometry accounts for 25.7% of total shape variation between skulls of different centroid sizes. Premaxillary crests are both taller and anteroposteriorly longer in larger skulls, a feature consistent with ontogenetic growth. A new diagnosis is proposed for Anhanguera, including traits that are nowadays known to be widespread within the genus, as well as ontogenetic changes. AMNH 22555 cannot be referred to “Anhanguera santanae” and, in fact, “Anhanguera santanae”, “Anhanguera araripensis”, and “Anhanguera robustus” are here considered nomina dubia.

Discussion
Historically, minor differences in crest morphology have been used in the definition of new anhanguerid species. Nowadays, this practice resulted in a considerable difficulty in referring well-preserved skulls into known taxa. When several specimens are analyzed, morphologies previously believed to be disparate are, in fact, separated by a continuum, and are thus better explained as individual or temporal variations. Stratigraphically controlled excavations on the Romualdo Formation have showed evidence for faunal turnover regarding fish communities. It is thus possible that some of the pterosaurs from this unit were not coeval, and might even represent anagenetic morphotypes. Unfortunately, amateur collecting of Romualdo Formation fossils, aimed especially at commerce, resulted in the lack of stratigraphic data of virtually all its pterosaurs and precludes testing of these further hypotheses.

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.

Pterosaurs possess skeletal pneumatization, which can be assessed externally through the observation of pneumatic foramina. These foramina vary in position, shape, and number among taxa. Here we propose new characters referring to the position and number of pneumatic foramina present in cervical and dorsal vertebrae of pterosaurs. A cladistic analysis was performed after first-hand study of material in collections and using data from the literature in order to test these new characters for homology, and they were subsequently mapped in a strict consensus tree. The analysis resulted in nine equally parsimonious trees with 215 steps each. The strict consensus tree obtained does not present significant differences in relation to trees obtained in previous studies. The mapping performed identified that most pneumatic foramina evolved independently in several lineages, and only two of the eight added characters appeared once in the evolution of pterosaurs. In general, pneumatic foramina were more common in the Dsungaripteroidea, however, the flattened preservation of non-pterodactyloids and in the Archaeopterodactyloidea often precludes their visualization, and therefore the presence of vertebral pneumatization may be broaden with the discovery of new, better preserved specimens.

Over a decade after the last major review of the Cambridge Greensand pterosaurs, their systematics remains one of the most disputed points in pterosaur taxonomy. Ornithocheiridae is still a wastebasket for fragmentary taxa, and some nomenclatural issues are still a problem. Here, the species from the Cretaceous of England that, at some point, were referred in Ornithocheirus, are reviewed. Investigation of the primary literature confirmed that Criorhynchus should be considered an objective junior synonym of Ornithocheirus. Taxonomic review of more than 30 species known from fragmentary remains showed that 16 of them are undiagnosable (nomina dubia): Palaeornis cliftii, Cimoliornis diomedeus, Pterodactylus compressirostris, Pterodactylus fittoni, Pterodactylus woodwardi, Ornithocheirus brachyrhinus, Ornithocheirus carteri, Ornithocheirus crassidens, Ornithocheirus dentatus, Ornithocheirus enchorhynchus, Ornithocheirus eurygnathus, Ornithocheirus oxyrhinus, Ornithocheirus scaphorhynchus, Ornithocheirus tenuirostris, Ornithocheirus xyphorhynchus, and Pterodactylus sagittirostris. Fourteen species are considered valid, and diagnoses are provided to all of them: Ornithocheirus simus, Lonchodraco giganteus comb. n., Lonchodraco machaerorhynchus comb. n., Lonchodraco(?) microdon comb. n., Coloborhynchus clavirostris, ‘Ornithocheirus’ capito, Camposipterus nasutus comb. n., Camposipterus(?) sedgwickii comb. n., Camposipterus(?) colorhinus comb. n., Cimoliopterus cuvieri comb. n., ‘Ornithocheirus’ polyodon, ‘Ornithocheirus’ platystomus, ‘Pterodactylus’ daviesii, and ‘Ornithocheirus’ denticulatus. These species are referred in the genera Ornithocheirus, Lonchodraco gen. n., Coloborhynchus, Cimoliopterus gen. n., and Camposipterus gen. n., but additional genera are probably present, as indicated by the use of single quotation marks throughout the text. A cladistic analysis demonstrates that Anhangueridae lies within a newly recognized clade, here named Anhangueria, which also includes the genera Cearadactylus, Brasileodactylus, Ludodactylus, and Camposipterus. The anhanguerian ‘Cearadactylus’ ligabuei belongs to a different genus than Cearadactylus atrox. Lonchodraconidae fam. n. (more or less equivalent to Lonchodectidae sensu Unwin 2001) is a monophyletic entity, but its exact phylogenetic position remains uncertain, as is the case of Ornithocheirus simus. Therefore, it is proposed that Ornithocheiridae should be constricted to its type species and thus is redundant. Other taxa previously referred as “ornithocheirids” are discussed in light of the revised taxonomy.

Flying reptiles from Australia are very rare, represented mostly by isolated bones coming from the Early Cretaceous (Albian) Toolebuc Formation, which crops out in western Queensland. Among the first pterosaur specimens discovered from this deposit is a mandibular symphysis that some authors thought to have a particular affinity to species found in the Cambridge Greensand (Cenomanian) of England. It was further referred as a member of or closely related to one of the genera Ornithocheirus, Lonchodectes or Anhanguera. Here we redescribe this specimen, showing that it cannot be referred to the aforementioned genera, but represents a new species of Pteranodontoid (sensu Kellner 2003), here named Aussiedraco molnari gen. et sp. nov. It is the second named pterosaur from Australia and confirms that the Toolebuc deposits are so far the most important for our understanding of the flying reptile fauna of this country.

Two almost complete long-tailed pterosaurs from the Linglongta, Jianchang County, western Liaoning, China, are described and represent new taxa referred to the non-pterodactyloid clade Wukongopteridae. Kunpengopterus sinensis gen. et sp. nov. differs from other members of this clade mainly by the rounded posterior region of the skull, thick lacrimal process of the jugal and lack of a bony premaxillary crest. This species further shows a soft tissue crest above the frontal, a comparatively larger wing finger, and the proximal segment of the second pedal phalanx of the fifth toe shorter than in other wukongopterids. The second new species is referred to the genus Darwinopterus, D. linglongtaensis sp. nov. based on the posterior region of the skull. It further differs from other wukongopterid pterosaurs by the thin lacrimal process of the jugal, foramen on nasal process rounded, and by having the second pedal phalanx of the fifth toe less curved (115°). Several differences among the Wukongopteridae can be found in the dentition and the feet, suggesting that they might have occupied slightly different ecological niches. The long-tailed Changchengopterus pani is tentatively referred to this clade and new diagnosis for the wukongopterids Wukongopterus lii and Darwinopterus modularis is provided.