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Mesozoic birds display considerable diversity in size, flight adaptations and feather organization 1 – 4 , but exhibit relatively conserved patterns of beak shape and development 5 – 7 . Although Neornithine (that is, crown group) birds also exhibit constraint on facial development 8 , 9 , they have comparatively diverse beak morphologies associated with a range of feeding and behavioural ecologies, in contrast to Mesozoic birds. Here we describe a crow-sized stem bird, Falcatakely forsterae gen. et sp. nov., from the Late Cretaceous epoch of Madagascar that possesses a long and deep rostrum, an expression of beak morphology that was previously unknown among Mesozoic birds and is superficially similar to that of a variety of crown-group birds (for example, toucans). The rostrum of Falcatakely is composed of an expansive edentulous maxilla and a small tooth-bearing premaxilla. Morphometric analyses of individual bony elements and three-dimensional rostrum shape reveal the development of a neornithine-like facial anatomy despite the retention of a maxilla–premaxilla organization that is similar to that of nonavialan theropods. The patterning and increased height of the rostrum in Falcatakely reveals a degree of developmental lability and increased morphological disparity that was previously unknown in early branching avialans. Expression of this phenotype (and presumed ecology) in a stem bird underscores that consolidation to the neornithine-like, premaxilla-dominated rostrum was not an evolutionary prerequisite for beak enlargement. A crow-sized stem bird, Falcatakely forsterae , possesses a long and deep rostrum—a beak morphology that was previously unknown among Mesozoic birds and is similar to that of some crown-group birds, such as toucans.

Rapetosaurus krausei is a titanosaur sauropod from the Upper Cretaceous Maevarano Formation of northwestern Madagascar and is among the most complete titanosaurs ever discovered. To date, over 15 localities in a 10 km2 field area have yielded hundreds of titanosaur bones, including associated and articulated specimens of Rapetosaurus. A juvenile skeleton is of particular significance because it was found directly associated with a well-preserved partial skull. The juvenile postcranial skeleton only lacks only the axis, atlas, representative elements from the proximal caudal series, carpals, and tarsals. The Rapetosaurus axial column consists of at least 17 cervical, 10 dorsal, six sacral, and 17 caudal vertebrae. Appendicular skeletal anatomy documents unique aspects of the titanosaur skeleton, and the association of large osteoderms with other, adult specimens confirms the lithostrotian status of Rapetosaurus. These new skeletal data have proven significant for phylogenetic resolution within Titanosauria, particularly because Rapetosaurus can be coded for 83% of over 400 characters for titanosaurs.

The extant anuran fauna of Madagascar is exceptionally rich and almost completely endemic. In recent years, many new species have been described and understanding of the history and relationships of this fauna has been greatly advanced by molecular studies, but very little is known of the fossil history of frogs on the island. Beelzebufo ampinga, the first named pre-Holocene frog from Madagascar, was described in 2008 on the basis of numerous disarticulated cranial and postcranial elements from the Upper Cretaceous (Maastrichtian) Maevarano Formation of Madagascar. These specimens documented the presence of a hyperossified taxon that differed strikingly from extant Malagasy frogs in its large size and heavy coarse cranial exostosis. Here we describe and analyse new, articulated, and more complete material of the skull, vertebral column, and hind limb, as well as additional isolated elements discovered since 2008. μCT scans allow a detailed understanding of both internal and external morphology and permit a more accurate reconstruction. The new material shows Beelzebufo to have been even more bizarre than originally interpreted, with large posterolateral skull flanges and sculptured vertebral spine tables. The apparent absence of a tympanic membrane, the strong cranial exostosis, and vertebral morphology suggest it may have burrowed during seasonally arid conditions, which have been interpreted for the Maevarano Formation from independent sedimentological and taphonomic evidence. New phylogenetic analyses, incorporating both morphological and molecular data, continue to place Beelzebufo with hyloid rather than ranoid frogs. Within Hyloidea, Beelzebufo still groups with the South American Ceratophryidae thus continuing to pose difficulties with both biogeographic interpretations and prior molecular divergence dates.

Recent fieldwork in the Upper Cretaceous (Maastrichtian) Maevarano Formation, northwest Madagascar, has yielded important new skull material of the abelisaurid theropod, Majungasaurus crenatissimus. One of these specimens in particular-a virtually complete, disarticulated, and well preserved skull-greatly elucidates the craniofacial osteology of abelisaurids. Herein we describe the skull and lower jaws of this mid-sized theropod dinosaur. A number of features of the facial skeleton and cranium (as well as the postcranium) appear to result from increased levels of mineralization and ossification, which, at least in some instances, can be related directly to specific soft-tissue structures; examples include lacrimal-postorbital contact dorsal to the orbit, suborbital processes of the lacrimal and postorbital, presence of a mineralized interorbital septum, fused interdental plates, and mineralization of the overlying integument. Autapomorphic features include a highly derived nasal-greatly thickened and fused to its counterpart, with a large interior pneumatic chamber-and a median, 'dome'-like thickening of the frontals, which appear to have been variably pneumatized by a paranasal air sac. Majungasaurus also possesses a derived suite of skull morphologies, including: a rostrocaudally abbreviated, dorsoventrally deep, and transversely broad skull; an expanded occiput, likely associated with expanded cervical musculature; short-crowned dentition; and an enlarged external mandibular fenestra consistent with a moderate degree of intramandibular movement or accommodation. A number of characters, present on both the skull and postcranial skeleton, suggest a divergent mode of predation relative to other, non-abelisaurid theropods.

Titanosauria is a clade of sauropod dinosaurs that includes species ranging from the largest known terrestrial vertebrates to insular dwarfs no bigger than elephants. Although most sauropod dinosaurs exhibit highly vascularized fibrolamellar bone signaling rapid growth rates comparable to those of extant mammals, diminutive titanosaurs apparently exhibit histological traits consistent with reduced primary growth rates and/or truncated active growth to reach small adult body sizes. A better understanding of the evolution of titanosaur body size requires additional sampling of the 40 + known titanosaur species. The best-preserved and most complete titanosaur yet discovered is Rapetosaurus krausei from the Maastrichtian Maevarano Formation in Madagascar. Skeletal material from many individuals spanning a wide range of ontogeny, from neonates to very large body sizes, makes Rapetosaurus an ideal candidate for an analysis of growth. We analyzed Rapetosaurus histology using a growth series of 25 forelimb, hind limb, and girdle elements representing different ontogenetic stages, including samples from the largest Rapetosaurus known (femur length = 143 cm). Primary bone histology in Rapetosaurus is highly vascularized fibrolamellar tissue, such as is found in other sauropods and most sampled titanosaurs. Secondary remodeling begins early, as noted in other titanosaur taxa, and by mid-ontogeny is pervasive in most sampled elements. The largest known Rapetosaurus was still growing, whereas some small juveniles exhibit an unusual pattern of bone erosion and replacement in the context of peripheral lines of arrested growth that signal a temporary pause in bone apposition. We hypothesize that these signals may relate to the drought-stressed ecosystem inhabited by Rapetosaurus.

Simosuchus clarki is a small, pug-nosed notosuchian crocodyliform from the Late Cretaceous of Madagascar. Originally described on the basis of a single specimen including a remarkably complete and well-preserved skull and lower jaw, S. clarki is now known from five additional specimens that preserve portions of the craniofacial skeleton. Collectively, these six specimens represent all elements of the head skeleton except the stapedes, thus making the craniofacial skeleton of S. clarki one of the best and most completely preserved among all known basal mesoeucrocodylians. In this report, we provide a detailed description of the entire head skeleton of S. clarki, including a portion of the hyobranchial apparatus. The two most complete and well-preserved specimens differ substantially in several size and shape variables (e.g., projections, angulations, and areas of ornamentation), suggestive of sexual dimorphism. Assessment of both external and internal morphological features indicates a habitual head posture in which the preorbital portion of the dermal skull roof was tilted downward at an angle of ∼45°. Functional and comparative assessment of the feeding apparatus strongly indicates a predominantly if not exclusively herbivorous diet. Other features of the craniofacial skeleton of S. clarki are consistent with the interpretation developed from analysis of the postcranial skeleton of a terrestrial habitus, but the current working hypothesis of a burrowing lifestyle is not supported. The atypical appearance of the skull and lower jaw of S. clarki is underscored by the identification of at least 45 autapomorphic features, many of them related to the greatly foreshortened snout.

Noasauridae is a clade of ceratosaurian theropods that evolved small body size independently of other nonavian theropods. The best-preserved and most complete noasaurid is Masiakasaurus knopfleri from the Maastrichtian-aged Maevarano Formation in Madagascar. An abundance of skeletal material from several individuals spanning a wide range of ontogeny makes Masiakasaurus an ideal candidate for the analysis of growth. We histologically sampled a growth series of elements consisting of four femora and three tibiae. Bright-field and circularly polarized light microscopy were used to distinguish between slowly and rapidly growing forms of bone. To simultaneously estimate age at death and reconstruct growth trajectories, we measured the perimeters of growth lines in each specimen and fitted models to these data using a novel application of mixed-effects regression. Our histological results show an external fundamental system in the largest tibial specimen and confirm that Masiakasaurus grew determinately, matured at small body size, and is not the juvenile form of a larger-bodied theropod. Parallel-fibered bone is unusually prominent and suggests relatively slow growth. Moreover, our quantitative analysis shows that the average individual took about 8-10 years to get to the size of a large dog. Although Masiakasaurus grew 40% faster than crocodylians, it grew about 40% slower than comparably sized non-avian theropods. Slowed growth may have evolved as a means to minimize structural and maintenance costs while living in a semiarid and seasonally stressful environment. Dimorphism does not appear related to asymptotic size or growth rate but seems to reflect the degree of skeletal maturity. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

The bizarre crocodyliform Simosuchus clarki shares several derived cranial characteristics with basal notosuchian taxa. In the original phylogenetic analysis assessing placement of Simosuchus among other crocodyliforms, it was recovered as a basal notosuchian. Additional preparation of the holotype skull and postcranium, and discovery of additional specimens, provides new information on the suite of morphologies in this notosuchian. Morphological analysis of all available material of S. clarki yields 60 autapomorphies distributed across the skeleton. To provide an updated test of the phylogeny of Notosuchia and placement of Simosuchus within the clade, we added seven new characters and expanded taxon sampling to include recently described notosuchians. A phylogenetic analysis of 301 characters and 84 crocodyliforms supports the position of Simosuchus as sister to Libycosuchus, more derived than Araripesuchus and Uruguaysuchus, and basal to other ziphosuchian notosuchians. We did not recover an Anatosuchus + Simosuchus clade, nor a monophyletic Araripesuchus, but did recover a peirosaurid clade including Peirosaurus, Lomasuchus, Uberabasuchus, and Hamadasuchus (but not Stolokrosaurus). We also found weak support for inclusion of Anatosuchus, Araripesuchus, Peirosauridae, and Mahajangasuchidae within Notosuchia and therefore for the conclusion that all basal mesoeucrocodylians from Gondwana, with the exception of Stolokrosuchus, are notosuchians. The results of this analysis demonstrate that basal mesoeucrocodylian relationships are currently in a state of flux and the need for caution in naming higher-level taxa until a more stable consensus topology is achieved. Similarly, large gaps in the notosuchian record render inconclusive the biogeographic origins of Simosuchus and the clade it represents on Madagascar.

We present the first digital reconstruction of the endocranial cavity and endosseous labyrinth of the Late Cretaceous gondwanatherian mammal Vintana sertichi from the Maevarano Formation of Madagascar. The Malagasy specimen is exceptionally well preserved and represents the only described cranium known for Gondwanatheria, an enigmatic clade from the Late Cretaceous and Paleogene of Gondwana. The endocranial cast of Vintana is relatively small for an animal of its estimated body mass. Its encephalization quotient is 0.28–0.56 for a range of body mass estimates, which is similar to that of basal mammaliaforms. The olfactory bulbs are very large, occupying over 14% of the endocranial volume. The cerebral hemispheres are only slightly expanded, more similar to the condition in Morganucodon than to that in multituberculates and monotremes. Unlike the condition in other Mesozoic mammaliaforms, the endocast is greatly flexed at the circular fissure. The osseous labyrinth displays a mixture of derived and primitive features. The cochlear canal is only slightly curved and short compared with that of extant therians. The ratio between total cochlear canal length and maximum cranial length is smaller than in basal mammaliaforms and approximates that of non-mammaliaform cynodonts. By contrast, the presence of both primary and secondary osseous laminae, the tractus foraminosus, and Rosenthal's canal represent derived characteristics of the mammalian inner ear typical of cladotherians. A modern innervation of the cochlea has either evolved independently in Vintana and cladotherians or was already present in the last common ancestor of both clades.

The Gondwanatheria are an enigmatic clade of Cretaceous and Paleogene mammals known from South America, Africa, Madagascar, India, and the Antarctic Peninsula. The eight valid species—each belonging to a monotypic genus and the first of which was described only 30 years ago—are represented almost exclusively by isolated teeth, in addition to fragmentary dentaries attributed to Sudamerica, Gondwanatherium, Ferugliotherium, and an unnamed taxon from Tanzania. No cranial (skull exclusive of lower jaw) or postcranial material has heretofore been assigned to the Gondwanatheria, a severe limitation that has precluded a comprehensive assessment of phylogenetic affinities. Here we describe, in detail, the first cranial specimen of a gondwanatherian mammal. This material consists of a complete and wellpreserved cranium of the sudamericid Vintana sertichi, recovered from the Upper Cretaceous (Maastrichtian) Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. Salient features of the cranium include elongate, scimitarlike jugal flanges, huge orbits, strong klinorhynchy, and a vaulted nuchal region. Micro-computed tomography greatly facilitated the delineation of sutures and the description of internal morphology. The cranial features of Vintana are compared with those of a broad range of synapsids, with particular concentration on other Mesozoic mammaliaforms. The cranium of Vintana exhibits a mosaic of extremely primitive and extremely derived features. It is the second largest known for a Mesozoic mammaliaform, superseded only by that of the eutriconodontan Repenomamus giganticus from the Early Cretaceous of China. Vintana is the largest known Late Cretaceous mammaliaform; it is also the largest known Mesozoic mammaliaform from Gondwana.