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The first Cretaceous bird from Madagascar
Abstract
WE report the discovery of two exquisitely preserved specimens of a new, very primitive bird from the Late Cretaceous period of Madagascar. The new taxon, Vorona berivotrensis, is provisionally placed phylogenetically in an unresolved trichotomy with Enantiornithes and a clade consisting of Patagopteryx and Ornithurae. These specimens are the first known pre-Holocene birds from Madagascar and the first avian skeletal remains from the Mesozoic era of a large portion of Gondwana.
... Outside Asia, well-preserved Early Cretaceous birds are mostly represented by Enantiornithes known from a handful of sites, including Las Hoyas in Spain and the Crato Formation in Brazil (e.g., Sanz and Lacasa, 1988;Sanz and Bonaparte, 1992;Sanz and Buscalioni, 1992;Sanz et al., 1996;Carvalho et al., 2015a, b). Ornithuromorpha is the clade that includes Patagopteryx deferrariisi Alvarenga andVorona berivotrensis Forster, Chiappe, Krause andSampson, 1996, Ornithurae, and all birds phylogenetically nested in between (Chiappe, 1996). Stem group ornithuromorphs were reported in Early Cretaceous beds, but they are very rare in number of specimens when compared with Enantiornithes (Zhou and Hou, 2002). ...
... In spite of a number of enantiornithine features, K. mater differs from Enantiornithes (including Cratoavis cearensis, which was found in roughly coeval beds; Carvalho et al., 2015a, b) in having a plantarly displaced metatarsal III. In Enantiornithes such as Yungavolucris brevipedalis, Avisaurus archibaldi, Soroavisaurus australis, and Gobipteryx minuta Elzȧnowski, 1974, as well as some basal ornithuromorphs such as Patagopteryx deferrariisi, Archaeorhynchus spathula, Bellulornis rectusunguis Wang, Zhou, and Zhou, 2016 and Vorona berivotrensis, the metatarsals are coplanar (Brett-Surman and Paul, 1985;Elzanowski, 1995;Chiappe, 1996Chiappe, , 2002Forster et al., 1996Forster et al., , 2002Wang, Zhou et al., 2016). In K. mater there is a slender shaft of metatarsal II, being subequal to slightly narrower to metatarsal IV, features that are widespread among non-enantiornithine basal birds. ...
... In K. mater the hypotarsus is mediolaterally stout and rounded, and does not form tendinal canals, or calcaneal crests as in modern birds, resembling in this aspect other basal ornithuromorphs such as Patagopteryx deferrariisi, Apsaravis ukhaana Clarke and Norell, 2002and hesperornithids (Chiappe, 1996Clarke and Norell, 2002;Bell and Everhart, 2009;Bell et al., 2015), whereas more basal ornithuromorphs lack signs of a hypotarsus (e.g., Archaeorhynchus spathula, Schizooura lii, Vorona berivotrensis, and Hollanda luceria; Forster et al., 1996;Zhou and Zhang, 2006;Bell et al., 2010;Kurochkin et al., 2011). ...
The fossil record of Early Cretaceous birds in South America has been restricted to members of Enantiornithes from the Crato Formation (Aptian) of Brazil. Here we describe a new genus and species of bird discovered at Pedra Branca Mine, Nova Olinda County, Ceará State, Brazil, which adds to the avian fossil record from the Crato Formation. The specimen is represented by an isolated foot that is exposed in plantar view. A plantarly displaced metatarsal III with a well-developed hypotarsus supports its referral to Ornithuromorpha, representing the oldest member of the clade reported for Gondwana. Its unique foot conformation indicates that it may belong to an unknown ornithuromorph clade with some cursory similarities to extant flightless ratites. The presence of Early Cretaceous ornithuromorphs in Brazil indicates that the clade was widespread in Gondwana during the Mesozoic.
http://zoobank.org/urn:lsid:zoobank.org:pub:08333BA3-F231-4E61-9E89-105C7478AE31
... Two paravians have been named from the Maevarano Fm.: Rahonavis ostromi , and the non-ornithurine avialan Vorona berivotrensis Forster et al., 1996 (see also Forster et al., 2002). A number of other mostly isolated avialan remains also have been recovered from the Maevarano Fm., including synsacra, humeri, coracoids, furculae, ulnae, radii, a carpometacarpus, a femur, tibiotarsae, and pedal elements; these specimens are fully described and illustrated in O' Connor and Forster (2010). ...
... However, scattered amongst these bones were elements belonging to turtles (isolated fragments of carapace), isolated vertebrae of the snake Madtsoia madagascariensis (see LaDuke et al., 2010), isolated teeth of the abelisaurid theropod Majungasaurus crenatissimus (see Sampson et al., 1998;Krause et al., 2007), isolated elements and teeth of the small abelisaurid theropod Masiakasaurus knopfleri (see Sampson et al., 2001;Carrano et al., 2002Carrano et al., , 2011, and a number of avialan bones. The avialan material belongs to Vorona berivotrensis (see Forster et al., 1996Forster et al., , 2002O'Connor and Forster, 2010), and at least five other unnamed taxa (O'Connor and Forster, 2010). ...
... The digital formula is 2-3-4-5(?)-0(?). There is no trace of a fifth metatarsal on either foot although its presence cannot be ruled out; MT V is present in Archaeopteryx (e.g., BMMS 500) and a variety of early branching birds (e.g., Forster et al., 1996;Zhou and Zhang, 2003). The metatarsus of Rahonavis is relatively short as the third metatarsal is only 40% of the length of the tibia, compared to approximately 54% in Archaeopteryx (e.g., NHMUK 37001) and 67% in Buitreraptor (Gianechini et al., 2018). ...
... Within the group, Austroraptor is typically recovered as a sister taxon of Unenlagia, which are both in turn sister to Buitreraptor (Turner et al., 2012;Agnolín and Novas, 2013;Pei et al., 2020). Rahonavis, originally described as a long, bony-tailed bird (Forster et al., 1996), has been identified as a member of the Unenlagiinae with additional referred material and anatomical work continuing to support that relationship (Forster et al., 2020), but some authors still find it to be an early-diverging avialan (Agnolín and Novas, 2013;Agnolín et al. 2019). Unenlagiine synapomorphies shared by some recent studies include a pubic shaft that is vertically oriented when articulated and an ilium with a reduced supraacetabular crest that is still separate from the antitrochanter (Foth et al., 2014;Pei et al., 2020) and has a postacetabular process with a concave dorsal edge (Agnolín and Novas, 2013;Pei et al., 2020). ...
... Rahonavis was originally described as an early-diverging avialan (Forster et al., 1996) and has been found in a later-diverging position than Archaeopteryx (Cau, 2018;Novas et al., 2018). However, it has also been recovered as a dromaeosaurid by a range of other studies Turner et al., 2012), which is the position favored in this volume. ...
New and important pennaraptoran specimens continue to be discovered on a regular basis. Yet, with these discoveries the number of viable phylogenetic hypotheses has increased, including ones that challenge the traditional grouping of dromaeosaurids and troodontids within a monophy-letic Deinonychosauria. This chapter will cover recent efforts to address prevailing phylogenetic uncertainties and controversies, both between and within key clades, including deinonychosaurian monophyly, the phylogenetic position of anchiornithines and scansoriopterygids, and the interrelationships of enantiornithines. While recent discoveries mainly from Asia have created much of the latest uncertainty and controversy, new material, particularly from Asia, promises to rather fittingly address these issues. Further curatorship of long-standing phylogenetic datasets and more prevalent use of extended analytical protocols will be essential to meeting this challenge, especially for groups whose boundaries have been blurred. As it becomes increasingly difficult to study all fossil materials, owing to their growing numbers and ever disparate locations, broader use of digital fossils and online character databases for character coding is acutely needed to ensure that errors arising from remote, rather than firsthand, scoring are reduced as far as possible, particularly at this time of rapid data accumulation.
... Within the group, Austroraptor is typically recovered as a sister taxon of Unenlagia, which are both in turn sister to Buitreraptor (Turner et al., 2012;Agnolín and Novas, 2013;Pei et al., 2020). Rahonavis, originally described as a long, bony-tailed bird (Forster et al., 1996), has been identified as a member of the Unenlagiinae with additional referred material and anatomical work continuing to support that relationship (Forster et al., 2020), but some authors still find it to be an early-diverging avialan (Agnolín and Novas, 2013;Agnolín et al. 2019). Unenlagiine synapomorphies shared by some recent studies include a pubic shaft that is vertically oriented when articulated and an ilium with a reduced supraacetabular crest that is still separate from the antitrochanter (Foth et al., 2014;Pei et al., 2020) and has a postacetabular process with a concave dorsal edge (Agnolín and Novas, 2013;Pei et al., 2020). ...
... Rahonavis was originally described as an early-diverging avialan (Forster et al., 1996) and has been found in a later-diverging position than Archaeopteryx (Cau, 2018;Novas et al., 2018). However, it has also been recovered as a dromaeosaurid by a range of other studies Turner et al., 2012), which is the position favored in this volume. ...
New and important pennaraptoran specimens continue to be discovered on a regular basis. Yet, with these discoveries the number of viable phylogenetic hypotheses has increased, including ones that challenge the traditional grouping of dromaeosaurids and troodontids within a monophyletic Deinonychosauria. This chapter will cover recent efforts to address prevailing phylogenetic uncertainties and controversies, both between and within key clades, including deinonychosaurian monophyly, the phylogenetic position of anchiornithines and scansoriopterygids, and the interrelationships of enantiornithines. While recent discoveries mainly from Asia have created much of the latest uncertainty and controversy, new material, particularly from Asia, promises to rather fittingly address these issues. Further curatorship of long-standing phylogenetic datasets and more prevalent use of extended analytical protocols will be essential to meeting this challenge, especially for groups whose boundaries have been blurred. As it becomes increasingly difficult to study all fossil materials, owing to their growing numbers and ever disparate locations, broader use of digital fossils and online character databases for character coding is acutely needed to ensure that errors arising from remote, rather than firsthand, scoring are reduced as far as possible, particularly at this time of rapid data accumulation.
... Africa: Avialan remains are yet to be discovered on the African continent although a large number of avialan bones have been collected from the Maastrichtian Maevarano Formation in nearby Madagascar, consisting of a diversity of enantiornithines (O'Connor and Forster, 2010) as well as the ornithuromorph, Vorona (Forster et al., 1996). Rahonavis was also described as an avialan from this formation, but although this was supported by some subsequent analyses (Agnolín and Novas, 2013;Cau, 2018;Novas et al., 2018), Rahonavis has also recognized as a dromaeosaurid by several studies Turner et al., 2012;Pei et al., in press). ...
An unabated surge of new and important discoveries continues to transform knowledge of pen-naraptoran biology and evolution amassed over the last 150+ years. This chapter summarizes progress made thus far in sampling the pennaraptoran fossil record of the Mesozoic and Paleocene and proposes priority areas of attention moving forward. Oviraptorosaurians are bizarre, nonparavian pennaraptorans first discovered in North America and Mongolia within Late Cretaceous rocks in the early 20th century. We now know that oviraptorosaurians also occupied the Early Cretaceous and their unquestionable fossil record is currently limited to Laurasia. Early Cretaceous material from China preserves feathers and other soft tissues and ingested remains including gastroliths and other stomach contents, while brooding specimens and age-structured, single-species accumulations from China and Mongolia provide spectacular behavioral insights. Less specialized early oviraptorosaurians like Incisivosaurus and Microvenator remain rare, and ancestral forms expected in the Late Jurassic are yet to be discovered, although some authors have suggested Epidexipteryx and possibly other scansoriopterygids may represent early-diverging oviraptorosaurians. Long-armed scansoriopterygids from the Middle-Late Jurassic of Laurasia are either early-diverging oviraptorosaurians or paravians, and some have considered them to be early-diverging avialans. Known from five (or possibly six) feathered specimens from China, only two mature individuals exist, representing these taxa. These taxa, Yi and Ambopteryx, preserve stylopod-supported wing membranes that are the only known alternative to the feathered, muscular wings that had been exclusively associated with dinosaurian flight. Thus, scansoriopterygid specimens-particularly those preserving soft tissue-remain a key priority for future specimen collection. Dromaeosaurids and troodontids were first discovered in North America and Mongolia in Late Cretaceous rocks. More recent discoveries show that these animals originated in the Late Jurassic, were strikingly feathered, lived across diverse climes and environments, and at least in the case of dromaeosaurids, attained a global distribution and the potential for aerial locomotion at small size.
... Therefore, this embryonic state can be inferred as continually present from the saurian common ancestor to crown-group birds. In extinct non-pygostylian archosaurs, the osteological correlate for this ligament (the fovea) is located between the AMT and the PMT off the tip of the femoral head long axis [15], whereas it is at the centre of the femoral head apex since early pygostylians (Confuciusornis [69]; enantiornithines [70][71][72][73]; and early euornithines [74,80,81] ) (figure 4a-h). Thus, during the evolution to pygostylians, the fovea seemingly relocated to the centre of the femoral head [82] as though the ligament itself shifted its insertion (figure 4e versus f; electronic supplementary material, SI.4). ...
Significant evolutionary shifts in locomotor behaviour often involve comparatively subtle anatomical transitions. For dinosaurian and avian evolution, medial overhang of the proximal femur has been central to discussions. However, there is an apparent conflict with regard to the evolutionary origin of the dinosaurian femoral head, with neontological and palaeontological data suggesting seemingly incongruent hypotheses. To reconcile this, we reconstructed the evolutionary history of morphogenesis of the proximal end of the femur from early archosaurs to crown birds. Embryological comparison of living archosaurs (crocodylians and birds) suggests the acquisition of the greater overhang of the femoral head in dinosaurs results from additional growth of the proximal end in the medial-ward direction. On the other hand, the fossil record suggests that this overhang was acquired by torsion of the proximal end, which projected in a more rostral direction ancestrally. We reconcile this apparent conflict by inferring that the medial overhang of the dinosaur femoral head was initially acquired by torsion, which was then superseded by mediad growth. Details of anatomical shifts in fossil forms support this hypothesis, and their biomechanical implications are congruent with the general consensus regarding broader morpho-functional evolution on the avian stem.
... Slightly younger deposits have yielded enantiornithines with an even wider distribution, present in Brazil (de Souza Carvalho et al., 2015) and Australia (Close et al., 2009), with the earliest hesperornithiforms preserved in late Albian deposits in the U.K. (Galton and Martin, 2002). During the Late Cretaceous, enantiornithines and later-diverging ornithuromorphs (ornithurines) had a global distribution, with records in Asia (e.g., Gobipteryx), South America (e.g., Patagopteryx), North America (e.g., Ichthyornis), Europe (e.g., Baptornis), Madagascar (Vorona), and Antarctica (Vegavis) (Elzanowski, 1974;Martin and Bonner, 1977;Alvarenga and Bonaparte, 1992;Forster et al., 1996;Clarke, 2004;Clarke et al., 2005). ...
The Coelurosauria are a group of mostly feathered theropods that gave rise to birds, the only dinosaurians that survived the Cretaceous-Paleogene extinction event and are still found today. Between their first appearance in the Middle Jurassic up to the end Cretaceous, coelurosaurians were party to dramatic geographic changes on the Earth’s surface, including the breakup of the supercontinent Pangaea, and the formation of the Atlantic Ocean. These plate tectonic events are thought to have caused vicariance or dispersal of coelurosaurian faunas, influencing their evolution. Unfortunately, few coelurosaurian biogeographic hypotheses have been supported by quantitative evidence. Here, we report the first, broadly sampled quantitative analysis of coelurosaurian biogeography using the likelihood-based package BioGeoBEARS. Mesozoic geographic configurations and changes are reconstructed and employed as constraints in this analysis, including their associated uncertainties. We use a comprehensive time-calibrated coelurosaurian evolutionary tree produced from the Theropod Working Group phylogenetic data matrix. Six biogeographic models in the BioGeoBEARS package with different assumptions about the evolution of spatial distributions are tested against geographic constraints. Our results statistically favor the DIVALIKE+J and DEC+J models, which allow vicariance and founder events, supporting continental vicariance as an important factor in coelurosaurian evolution. Ancestral range estimation indicates frequent dispersal events via the Apulian route (connecting Europe and Africa during the Early Cretaceous) and the Bering land bridge (connecting North America and Asia during the Late Cretaceous). These quantitative results are consistent with commonly inferred Mesozoic dinosaurian dispersals and continental-fragmentationinduced vicariance events. In addition, we recognize the importance of Europe as a dispersal center and gateway in the Early Cretaceous, as well as other vicariance events such as those triggered by the disappearance of land bridges.
... The fibula bears a craniolaterally directed tubercle for the insertion of m. iliofibularis at the level approximately one-quarter of the distance from the proximal end of the tibiotarsus. In contrast, that tubercle is laterally directed in the basal ornithuromorphs Patagopteryx deferrariisi and Vorona berivotrensis (Forster et al., 1996), but caudally or caudolaterally oriented in Ornithurae (Chiappe, 1996). The distal end of the fibula is missing, precluding assessment of its total length. ...
Confuciusornithidae is the clade of Early Cretaceous birds most rich in materials and plays a central role in our understanding of the evolution of avian horny beaks and pygostyles. A handful of specimens demonstrate that this avian group is distinguishable from other basal birds by their robust, toothless upper and lower jaws, a fused scapulocoracoid and a tiny claw on the middle manual digit, among other features. Here, we report a new taxon of Confuciusornithidae, Yangavis confucii gen. et sp. nov., from the Early Cretaceous Jehol Biota, northeastern China. This new bird, however, has a normal-sized major digit claw, as in other basal birds, which was probably regained independently as Confuciusornithidae evolved, based on our phylogenetic study. Unfortunately, the biological significance of this trait is unclear owing to a lack of analogues in modern birds (manual claws are completely lost in adults). Yangavis confucii is differentiated from other confuciusornithids by its proportionally much longer forelimb. Our morphometric analysis indicates that the morphospace of Confuciusornithidae, with the addition of Y. confucii, is greatly broadened to a degree that it overlaps with the Early Cretaceous Ornithuromorpha and Enantiornithines, indicating that the biological diversity of confuciusornithids is greater than previously thought.
... Slightly younger deposits have yielded enantiornithines with an even wider distribution, present in Brazil (de Souza Carvalho et al., 2015) and Australia (Close et al., 2009), with the earliest hesperornithiforms preserved in late Albian deposits in the U.K. (Galton and Martin, 2002). During the Late Cretaceous, enantiornithines and later-diverging ornithuromorphs (ornithurines) had a global distribution, with records in Asia (e.g., Gobipteryx), South America (e.g., Patagopteryx), North America (e.g., Ichthyornis), Europe (e.g., Baptornis), Madagascar (Vorona), and Antarctica (Vegavis) (Elzanowski, 1974;Martin and Bonner, 1977;Alvarenga and Bonaparte, 1992;Forster et al., 1996;Clarke, 2004;Clarke et al., 2005). ...
The Coelurosauria are a group of mostly feathered theropods that gave rise to birds, the only dinosaurians that survived the Cretaceous-Paleogene extinction event and are still found today. Between their first appearance in the Middle Jurassic up to the end Cretaceous, coelurosaurians were party to dramatic geographic changes on the Earth's surface, including the breakup of the supercontinent Pangaea, and the formation of the Atlantic Ocean. These plate tectonic events are thought to have caused vicariance or dispersal of coelurosaurian faunas, influencing their evolution. Unfortunately , few coelurosaurian biogeographic hypotheses have been supported by quantitative evidence. Here, we report the first, broadly sampled quantitative analysis of coelurosaurian biogeography using the likelihood-based package BioGeoBEARS. Mesozoic geographic configurations and changes are reconstructed and employed as constraints in this analysis, including their associated uncertainties. We use a comprehensive time-calibrated coelurosaurian evolutionary tree produced from the The-ropod Working Group phylogenetic data matrix. Six biogeographic models in the BioGeoBEARS package with different assumptions about the evolution of spatial distributions are tested against geographic constraints. Our results statistically favor the DIVALIKE+J and DEC+J models, which allow vicariance and founder events, supporting continental vicariance as an important factor in coelurosaurian evolution. Ancestral range estimation indicates frequent dispersal events via the Apulian route (connecting Europe and Africa during the Early Cretaceous) and the Bering land bridge (connecting North America and Asia during the Late Cretaceous). These quantitative results are consistent with commonly inferred Mesozoic dinosaurian dispersals and continental-fragmentation-induced vicariance events. In addition, we recognize the importance of Europe as a dispersal center and gateway in the Early Cretaceous, as well as other vicariance events such as those triggered by the disappearance of land bridges.
... Africa: Avialan remains are yet to be discovered on the African continent although a large number of avialan bones have been collected from the Maastrichtian Maevarano Formation in nearby Madagascar, consisting of a diversity of enantiornithines (O'Connor and Forster, 2010) as well as the ornithuromorph, Vorona (Forster et al., 1996). Rahonavis was also described as an avialan from this formation, but although this was supported by some subsequent analyses (Agnolín and Novas, 2013;Cau, 2018;Novas et al., 2018), Rahonavis has also recognized as a dromaeosaurid by several studies Turner et al., 2012;Pei et al., in press). ...
An unabated surge of new and important discoveries continues to transform knowledge of pen-naraptoran biology and evolution amassed over the last 150+ years. This chapter summarizes progress made thus far in sampling the pennaraptoran fossil record of the Mesozoic and Paleocene and proposes priority areas of attention moving forward. Oviraptorosaurians are bizarre, nonparavian pennaraptorans first discovered in North America and Mongolia within Late Cretaceous rocks in the early 20th century. We now know that oviraptorosaurians also occupied the Early Cretaceous and their unquestionable fossil record is currently limited to Laurasia. Early Cretaceous material from China preserves feathers and other soft tissues and ingested remains including gastroliths and other stomach contents, while brooding specimens and age-structured, single-species accumulations from China and Mongolia provide spectacular behavioral insights. Less specialized early oviraptorosaurians like Incisivosaurus and Microvenator remain rare, and ancestral forms expected in the Late Jurassic are yet to be discovered, although some authors have suggested Epidexipteryx and possibly other scansoriopterygids may represent early-diverging oviraptorosaurians. Long-armed scansoriopterygids from the Middle-Late Jurassic of Laurasia are either early-diverging oviraptorosaurians or paravians, and some have considered them to be early-diverging avialans. Known from five (or possibly six) feathered specimens from China, only two mature individuals exist, representing these taxa. These taxa, Yi and Ambopteryx, preserve stylopod-supported wing membranes that are the only known alternative to the feathered, muscular wings that had been exclusively associated with dinosaurian flight. Thus, scansoriopterygid specimens-particularly those preserving soft tissue-remain a key priority for future specimen collection. Dromaeosaurids and troodontids were first discovered in North America and Mongolia in Late Cretaceous rocks. More recent discoveries show that these animals originated in the Late Jurassic, were strikingly feathered, lived across diverse climes and environments, and at least in the case of dromaeosaurids, attained a global distribution and the potential for aerial locomotion at small size.
More than half of the evolutionary history of birds is played out in the Mesozoic. A recent burst of fossil discoveries has documented a tremendous diversity of early avians. Clarification of the Phylogenetic structure of this diversity has provided clues for a better understanding of the evolution of functional, developmental and physiological characteristics of modern birds. Yet their long Mesozoic history is only beginning to be deciphered.
THE Late Cretaceous rocks of Mongolia have produced unusual and phylogenetically important dinosaurs1,2. Here we report a startling new example, Mononychus olecranus gen. et sp. nov., an avialian theropod dinosaur with a short, robust forelimb possessing a single stout claw. Several features, including a carinate sternum and reduced fibula, suggest that Mononychus olecranus is more closely related to modern birds than is Archaeopteryx lithographica. The two skeletons are among the best preserved fossils known of a primitive bird, and emphasize the complexity of the morphological transformation from nonavialian theropods to modern birds. The occurrence of such a primitive bird in the Late Cretaceous reflects the paucity of Mesozoic bird fossils and suggests that the early radiation of avialians is only beginning to be sampled.
Widespread basalts and rhyolites were erupted in Madagascar during the Late Cretaceous. These are considered to be related
to the Marion hot spot and the breakup of Madagascar and Greater India. Seventeen argon-40/argon-39 age determinations reveal
that volcanic rocks and dikes from the 1500-kilometer-long rifted eastern margin of Madagascar were emplaced rapidly (mean
age = 87.6 ± 0.6 million years ago) and that the entire duration of Cretaceous volcanism on the island was no more than 6
million years. The evidence suggests that the thick lava pile at Volcan de l'Androy in the south of the island marks the focal
point of the Marion hot spot at ∼88 million years ago and that this mantle plume was instrumental in causing continental breakup.
Current classification of birds recognizes four subclasses: the Archaeornithes, the Enantiornithes, the Odontornithes and the Neornithes. Three of these subclasses were proposed during the nineteenth century, but the Enantiornithes was proposed only five years ago, based on material from the Lecho Formation (Maas-trichtian) of Salt a Province in Argentina1. Further material from Asia (Mongolia) and North America (Mexico) has been referred to the Enantiornithes2, all of it from the Campanian. Now, in addition, a small tibiotarsus found in the Lower Cretaceous (Albian) of Queensland not only represents the first bony material of Mesozoic birds from Australia, but is also the first reported occurrence of an enantiornithine bird in the Lower Cretaceous.
According to a traditional but hitherto untested reconstruction of Madagascar’s Holocene environment, continuous forest preceded
the monotonous grassland formations that now cover most of the island’s interior. Preliminary analyses of pollen samples collected
near14C-dated horizons at Ampasambazimba (central Madagascar) indicate that a mosaic of woodlands, bushlands, and savanna existed
close to this important vertebrate subfossil site around 7000–8000 BP. Although most members of Madagascar’s recently extinct
“subfossil” fauna are thought to have been forest dwellers, several may have preferred a more open habitat like the one inferred
for the region of Ampasambazimba. Dry savanna-woodland burns more readily than does dense forest and may have been more severely
affected by the forces which transformed the Malagasy environment during the later Holocene. If so, the loss of savanna-woodland,
not dense forest, may have been an important factor in the subfossil extinctions.