A Basal Tapejarine (Pterosauria; Pterodactyloidea; Tapejaridae) from the Crato Formation, Early Cretaceous of Brazil

RESEARCH ARTICLE A Basal Tapejarine (Pterosauria; Pterodactyloidea; Tapejaridae) from the Crato Formation, Early Cretaceous of Brazil Rodrigo Vargas Pêgas1*, Maria Eduarda de Castro Leal2, Alexander Wilhelm Armin Kellner1 a11111 1 Laboratory of Systematics and Taphonomy of Fossil Vertebrates, Departamento de Geologia e Paleontologia, Universidade Federal do Rio de Janeiro, Museu Nacional, Rio de Janeiro, Brazil, 2 Departamento de Geologia, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil * Abstract OPEN ACCESS Citation: Pêgas RV, Leal MEdC, Kellner AWA (2016) A Basal Tapejarine (Pterosauria; Pterodactyloidea; Tapejaridae) from the Crato Formation, Early Cretaceous of Brazil. PLoS ONE 11(9): e0162692. doi:10.1371/journal.pone.0162692 Editor: William Oki Wong, Institute of Botany, CHINA Received: May 29, 2016 Accepted: August 22, 2016 Published: September 21, 2016 Copyright: © 2016 Pêgas et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. A three-dimensional and almost complete pterosaur mandible from the Crato Formation (Early Cretaceous of Northeastern Brazil), Araripe Basin, is described as a new species of a tapejarine tapejarid. Tapejarines are a particular group of toothless pterosaurs, characterized by well-developed cranial crests, downturned rostra, and have been proposed to represent frugivorous flying reptiles. Though comparatively well represented and distributed, the evolutionary history of the group is still poorly known, and the internal relationships of its members are not well understood. The new species here reported, named Aymberedactylus cearensis gen. et sp. nov., adds new data concerning the evolution of the group, concerning their morphology and geographical origin. It differs from known tapejarids due to its unusually elongate retroarticular process and a shallow fossa on the splenial exhibiting distinctive rugose texture. Furthermore,it exhibits a suite of basal and derived conditions within the Tapejaridae, demonstrating how their morphological traits probably evolved and that these forms were even more diverse than already acknowledged. The discovery of Aymberedactylus cearensis sheds new light on the evolutionary history of the Tapejarinae. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) http://www. faperj.br/ Grant numbers 213265 to RVP and E-26/ 102.737/2012to AWAK. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) http://cnpq.br/ Grant number CNPq 304780/2013-8 to AWAK. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) & Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP) http://www.funcap.ce.gov.br/ Grant number CNPq/FUNCAP-DCR/305426/2014-1 to MECL. The funders had no role in study design, Introduction The Tapejaridae are a clade of toothless pterosaurs easily recognized by their well-developed cranial sagittal crests and particularly large nasoantorbital fenestrae [1–5]. The clade has been split into the subfamilies Thalassodrominae and Tapejarinae: whereas thalassodromine tapejarids display straight dorsal jaw margins and premaxillary crests that extend very high posteriorly, tapejarines typically display short, downturned jaws and premaxillary crests anteriorly high that constrict posteriorly, and well-developed dentary crests [5]. The Tapejarinae include at least ten species ranging from the Barremian to the Turonian-Campanian [6, 7], and displaying a widespread geographic distribution, having been found in Brazil, China, Morocco and Spain [8]. These pterosaurs typically display an occlusal gap and a step-like dorsal margin of PLOS ONE | DOI:10.1371/journal.pone.0162692 September 21, 2016 1 / 17 A Basal Tapejarine Pterosaur from the Crato Formation data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. the dentary symphyses, traits that have been interpreted as linked to a frugivore diet [9]. The presence of fruits in the diet of tapejarines has been subsequently accepted by several workers [7, 8, 10–13]. The Thalassodrominae, in contrast, are much less diverse, with a very narrow geographic distribution that could suggest an endemic pattern. So far, all described and confirmed species come from the Romualdo Formation (Aptian-Albian, Santana Group, Araripe Basin): Tupuxuara longicristatus, Tupuxuara leonardii and Thalassodromeus sethi [6]. A fourth thalassodromine species from the same formation, “Tupuxuara deliradamus”, has been proposed [14], and later invalidated [6]. Another described species, Lacusovagus magnificens from the Crato Formation (Aptian, Santana Group, Araripe Basin), was assigned to the Chaoyangopteridae [15], but could be a thalassodromine [6, 16]. So far, pterosaur taxa from the clades Anhangueria (sensu Rodrigues & Kellner, 2013 [17] and Azhdarchoidea (sensu Kellner, 2003 [2]) are known from the Crato Formation. The former are represented by Brasileodactylus araripensis [18] and Ludodactylus sibbicki [19], whereas the latter are represented by the tapejarine tapejarids Tupandactylus imperator [20] and Tupandactylus navigans [21], plus the indeterminate azhdarchoid Lacusovagus magnificens. All of those are known from isolated cranial material. Over three hundred indeterminate postcranial specimens from the Crato Formation have been assigned to the same clades [12]. Here we report a new species of pterosaur from the Crato Formation, based on a single three-dimensional lower jaw. In virtue of its toothlessness, slightly downturned dentary symphysis and vestiges of a dentary crest, it can be identified as a tapejarine. It displays a unique combination of thalassodromine-like and tapejarine features, which together suggest its placement as a basal tapejarine. This inference is corroborated by a phylogenetic analysis presented here. The new species exhibits a novel morphology among its relatives and provides new insights into tapejarid diversity and tapejarine evolution. Geological Setting The Santana Group of Araripe Basin, located in Northeastern Brazil, records the transgressionregression cycle taking place in the Afro-Brazilian rift system during the Aptian-Albian worldwide marine transgression [22–25]. It contains two of the most important Mesozoic fossil Konservat Lagerstätte on Gondwana, the Crato and Romualdo Formations [22–26]. The Crato Formation comprises mostly micritic laminated limestone rocks, interpreted as deposits from the shallow waters of a coastal lagoon with both marine and fluvial influences [23]. Although its fossils are generally compressed to some level, these beds are famous fo (...truncated)