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Madagascar has a diverse but mainly endemic frog fauna, the biogeographic history of which has generated intense debate, fueled by recent molecular phylogenetic analyses and the near absence of a fossil record. Here, we describe a recently discovered Late Cretaceous anuran that differs strikingly in size and morphology from extant Malagasy taxa and is unrelated either to them or to the predicted occupants of the Madagascar-Seychelles-India landmass when it separated from Africa 160 million years ago (Mya). Instead, the previously undescribed anuran is attributed to the Ceratophryinae, a clade previously considered endemic to South America. The discovery offers a rare glimpse of the anuran assemblage that occupied Madagascar before the Tertiary radiation of mantellids and microhylids that now dominate the anuran fauna. In addition, the presence of a ceratophryine provides support for a controversial paleobiogeographical model that posits physical and biotic links among Madagascar, the Indian subcontinent, and South America that persisted well into the Late Cretaceous. It also suggests that the initial radiation of hyloid anurans began earlier than proposed by some recent estimates.

Two new insect-related ichnogenera are reported in fossil dinosaur bones from Upper Cretaceous continental strata in Madagascar and Utah. Cubiculum ornatus n. igen. and isp. is described from numerous fossil bones in the Upper Cretaceous Maevarano Formation of northwestern Madagascar, and consists of hollow, ovoid chambers with concave flanks excavated into both spongy and compact bone. Traces similar in morphology to Cubiculum ornatus have been reported elsewhere in North America, Asia, Europe, and Africa in bones ranging in age from Jurassic to Pleistocene, and have been interpreted as pupal chambers constructed by carrion beetle larvae. Osteocallis mandibulus n. igen. and isp. is described in dinosaur bones from continental deposits of the Upper Cretaceous Maevarano Formation of Madagascar and the Upper Cretaceous Kaiparowits Formation of southern Utah. O. mandibulus consists of shallow, meandering surface trails, composed of numerous arcuate grooves, bored into compact (cortical) bone surfaces, and is tentatively interpreted as a feeding trace. Based on similar patterns of bioglyph preserved in both Cubiculum ornatus and Osteocallis mandibulus, the tracemaker is interpreted to be the same or similar for both borings. Given the recurrent association with animal remains, the tracemaker is furthermore presumed to be a necrophagous or osteophagous insect that used bone as a substrate for both reproduction (C. ornatus) and feeding (O. mandibulus).

An assemblage of large-diameter vertical burrows interpreted as lungfish estivation burrows is documented from the Upper Cretaceous (Maastrichtian) Maevarano Formation of northwestern Madagascar. These burrows suggest that lungfish were present in the Maevarano Formation paleofauna, and they are the first lungfish estivation burrows described from the rock record of Gondwana. Over 100 large-diameter burrows penetrate a pervasively cross-stratified fluvial sandstone body intercalated near the top of the Masorobe Member. The surface of this sandstone body was mapped and 74 burrows were documented in an area spanning ∼110 m2. Burrows cut through and deform surrounding foreset laminae, and in some cases impact surrounding strata up to 8 cm from the edges of individual burrows. In map view, the burrows exhibit three distinctive morphologies: circular, elliptical, and figure-eight shaped. These three map view cross sections are very similar to the modern burrow morphology of the African lungfish Protopterus when its burrow is exhumed along its full vertical expanse. Combined, these transverse-section views provide indication of lungfish estivation, and they are supplemented by several additional key characteristics, including spatial clustering (reflecting gregarious behavior), possible fin traces, and oxidized burrow margins. The localized occurrence of 100+ lungfish estivation burrows is consistent with previous reconstructions that posit a dryland paleoenvironment with a markedly seasonal wet-dry climate for the Maevarano Formation.

As prominent abrupt climatic events during the last deglaciation and the early Holocene, the Younger Dryas (YD) and the 8.2 ka events have been intensely discussed to reveal the relationship between their phases and intensities, and their underlying mechanisms based on massive marine and terrestrial archives. However, the related paleoclimate records with sufficient resolution and/or precise age constraints from the Southern Hemisphere, especially East Africa, are relatively sparse, hindering our comprehensive understanding about the phases of these two events. Here, we provide a precisely dated record of an aragonite-calcite stalagmite covering 11.3–13.5 ka BP from northwest Madagascar to unravel the arid conditions during the YD, in contrast to the pluvial conditions in the 8.2 ka event that has been evidenced before. Changes in austral summer precipitation related to the Intertropical Convergence Zone (ITCZ) have always been interpreted to be the primary means of controlling regional rainfall amounts and thus the δ18O variations in stalagmite. However, ITCZ’s meridional migration alone is not enough to interpret the opposite hydroclimatic conditions during the YD and the 8.2 ka events in northwest Madagascar. The variation in convection intensity within the ITCZ combined with the rainfall dipole mode in East Africa, and the redistribution of the duration of the ITCZ’s presence at different latitudes might be responsible for this phenomenon. In addition, sea surface temperature could play a nonnegligible role.

Although the image of crocodyliforms as ‘unchanged living fossils’ is naive, several morphological features of the group are thought to have varied only within narrow limits during the course of evolution 1 . These include an elongate snout with an array of conical teeth, a dorsoventrally flattened skull and a posteriorly positioned jaw articulation, which provides a powerful bite force. Here we report an exquisitely preserved specimen of a new taxon from the Late Cretaceous of Madagascar that deviates profoundly from this Bauplan, possessing an extremely blunt snout, a tall, rounded skull, an anteriorly shifted jaw joint and clove-shaped, multicusped teeth reminiscent of those of some ornithischian dinosaurs. This last feature implies that the diet of the new taxon may have been predominantly if not exclusively herbivorous. A close relationship with notosuchid crocodyliforms, particularly Uruguaysuchus (Late Cretaceous, Uruguay) 2 is suggested by several shared derived features; this supports a biogeographical hypothesis that Madagascar and South America were linked during the Late Cretaceous 3 .

Rapetosaurus krausei (Sauropoda: Titanosauria) from the Upper Cretaceous Maevarano Formation of Madagascar is the best-preserved and most complete titanosaur yet described. The skull of Rapetosaurus is particularly significant because most titanosaurs are diagnosed solely on the basis of fragmentary postcranial material, and knowledge of the titanosaur skull has remained incomplete. Material referred to Rapetosaurus includes the type skull from an adult that preserves the basicranium, rostrum, mandible, and palate. A second, juvenile skull preserves most of the braincase and cranial vault, as well as some of the palate and lower jaw. Here we provide a detailed description of Rapetosaurus cranial anatomy and highlight comparative relationships among known titanosaur and other neosauropod skulls. The Rapetosaurus skull is similar to those of diplodocoids in its overall shape, with retracted external nares and an elongated snout. However, extensive tooth distribution and bone articulations surrounding the external narial region and orbit are more similar to those of macronarians like Camarasaurus and Brachiosaurus. The maxilla, basicranium, paroccipital process, and pterygoid are among the most diagnostic elements of the Rapetosaurus skull, along with the enlarged antorbital fenestra, anteroventrally oriented braincase, and mandible. Titanosaur crania exhibit a greater diversity than previously recognized and, in light of Rapetosaurus, it is apparent that there is not a narrowly constrained bauplan for the skull of titanosaurs. Broad generalizations about evolution based on previously known, fragmentary fossils require re-evaluation. Ultimately, Rapetosaurus will be key in resolving titanosaur higher-level and ingroup phylogeny.

Here we report the discovery of a small-bodied (∼1.8 m) predatory dinosaur from the Late Cretaceous (Maastrichtian) of Madagascar. Masiakasaurus knopfleri , gen. et sp. nov., represented by several skull elements and much of the postcranial skeleton, is unique in being the only known theropod with a highly procumbent and distinctly heterodont lower dentition. Such a derived dental morphology is otherwise unknown among dinosaurs. Numerous skeletal characteristics indicate that Masiakasaurus is a member of Abelisauroidea, an enigmatic clade of Gondwanan theropods. Previously, small-bodied abelisauroids were known only from Argentina 1 , 2 , 3 . The occurrence of Masiakasaurus on Madagascar suggests that small-bodied abelisauroids, like their larger-bodied counterparts, were more cosmopolitan, radiating throughout much of Gondwana and paralleling the diversification of small coelurosaur theropods in Laurasia.

We report here the first unequivocal record of a pre-Late Pleistocene lizard from the island of Madagascar, based on a nearly complete lower jaw, elements of both the pectoral and pelvic girdles, several vertebrae and ribs, and numerous osteoderms of what is presumed to be a single individual. The specimen, recovered from the Upper Cretaceous (Maastrichtian) Anembalemba Member, Maevarano Formation, Mahajanga Basin, northwestern Madagascar, is identified as a scincoid scincomorph and, more specifically, a new genus and species of ?Cordylidae (Cordyliformes), based on a combination of gnathic, dental, and postcranial characters. The new taxon is the first identifiable lizard from the Late Cretaceous of the African continent (sensu lato). If the new taxon is correctly attributed to the Cordylidae, it constitutes a significant temporal and geographic range extension for the clade since cordylids have no definite representatives in the fossil record and extant forms are restricted to the sub-Saharan portion of mainland Africa. This new record also indicates that cordylids, after their occurrence in the Maastrichtian, became extinct on Madagascar, leaving only zonosaurine Gerrhosauridae as extant representatives of Cordyliformes on the island. Owing to limited knowledge concerning the time of divergence for cordylids and gerrhosaurids relative to the tectonic separation of Africa and Madagascar, and in light of the paucity of Mesozoic lizard fossils in general, and from Gondwana in particular, the discovery of the new taxon in the Late Cretaceous of Madagascar does little to otherwise constrain scenarios concerning the biogeographic history of early cordyliforms. Finally, we document here the observation that lizards appear to have been much less speciose than snakes in Late Cretaceous faunas of Gondwana, whereas the reverse is true in Laurasia. Lizards do not appear to become common in Gondwana until the Early Tertiary.

Upper Cretaceous strata of the Mahajanga Basin, northwestern Madagascar, yield some of the most significant and exquisitely preserved vertebrate fossils known from Gondwana. The sedimentology of these strata and their stratigraphic relations have been the focus of renewed geological investigations during the course of five expeditions since 1993. We here designate stratotypes and formalize the terrestrial Maevarano Formation, with three new members (Masorobe, Anembalemba, Miadana), and the overlying marine Berivotra Formation. The Maevarano Formation accumulated on a broad, semiarid alluvial plain bounded to the southeast by crystalline highlands and to the northwest by the Mozambique Channel. The Berivotra Formation was deposited in an open marine setting that evolved from a clastic‐ to a carbonate‐dominated shelf, resulting in deposition of the overlying Betsiboka limestone of Danian age. New stratigraphic data clearly indicate that the Maevarano Formation correlates, at least in part, with the Maastrichtian Berivotra Formation, and this in turn indicates that the most fossiliferous portions of the Maevarano Formation are Maastrichtian in age, rather than Campanian as previously reported. This revised age for the Maevarano vertebrate assemblage indicates that it is approximately contemporaneous with the vertebrate fauna recovered from the Deccan basalt volcano‐sedimentary sequence of India. The comparable age of these two faunas is significant because the faunas appear to be more similar to one another than either is to those from any other major Gondwanan landmass. The revised age of the Maevarano Formation, when considered in the light of our recent fossil discoveries, further indicates that the ancestral stocks of Madagascar's overwhelmingly endemic modern vertebrate fauna arrived on the island in post‐Mesozoic times. The basal stocks of the modern vertebrate fauna are conspicuously absent in the Maevarano Formation. Finally, the revised age of the Maevarano Formation serves to expand our global perspective on the K/T event by clarifying the age of a diverse, and arguably the best preserved, sample of Gondwanan vertebrates from the terminal Cretaceous.

Recently discovered reptile specimens from the \"Eotriassic\" deposits of Madagascar (Lower Triassic) are reported, adding valuable information to our knowledge of Malagasy faunas and providing additional data on tetrapod survivorship across the Permian-Triassic (P-T) boundary. Four specimens are attributable to the terrestrial procolophonoid Barasaurus besairiei Piveteau 1955, whereas the remainder are referable to the aquatic younginiform family Tangasauridae, including some individuals identifiable as Hovasaurus boulei Piveteau 1926. These specimens represent the geologically youngest tangasaurid and Barasaurus specimens to be described from Madagascar and suggest that these small reptiles passed unaffected through the end Permian mass extinction event, when ∼78% of amniote families disappeared.