Sinoergilornis guangheensis gen. et sp. nov.Â
Grace Musser, Zhiheng Li & ÂJulia A Clarke (2019)
A new species of Eogruidae (Aves: Gruiformes) from the Miocene of the Linxia Basin, Gansu, China: Evolutionary and climatic implications.
The Auk: ukz067 (advance online publication)
doi:
https://doi.org/10.1093/auk/ukz067https://academic.oup.com/auk/advance-article-abstract/doi/10.1093/auk/ukz067/5645102 Despite having one of the most robust fossil records within core-gruiform birds (rails, cranes, and allies), the biogeographic history of Gruidae (cranes) and key drivers of diversification within this group remain largely unknown. The Eogruidae of Eurasia represent some of the earliest known crane-like fossils. Here, we present description of a new species represented by a well-preserved specimen of a foot from the late Miocene (7â6.5 mya) Liushu Formation of Linxia Basin, Gansu, China. It is the only eogruid fossil that has been found in this formation and is the first eogruid known from northwest China. Linxia Basin is located along the margin of the northeastern Tibetan Plateau, which allows for new insight into Miocene dispersal of the Eogruidae and potential climatological and geological connections. It is also the first specimen with an associated tarsometatarsus and nearly complete phalanges, including a claw, which provides further morphological information on this taxon. Referral of the new specimen to Eogruidae is based on extreme reduction of the trochlea of metatarsal II, which is most similar to the condition present in the eogruid subclade traditionally termed Ergilornithidae.
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Giovanne M. Cidade, Douglas Riff & Annie Schmaltz Hsiou (2019)
The feeding habits of the strange crocodylian Mourasuchus (Alligatoroidea, Caimaninae): a review, new hypotheses and perspectives.
Revista Brasileira de Paleontologia 22(2):106â119
doi:10.4072/rbp.2019.2.03
http://www.sbpbrasil.org/assets/uploads/files/rbp2019203.pdfThe caimanine crocodylian Mourasuchus from the Miocene of South America is one of the most peculiar crocodylomorphs of all time. It exhibits an unusual long, wide and dorsoventrally flattened rostrum, long, slender mandibles, and relatively short cervical vertebrae. These features have led previous authors to propose that the feeding habits of Mourasuchus were very different from those of most crocodylomorphs. In order to significantly improve the knowledge on the feeding habits of Mourasuchus, we performed a comprehensive review on this issue in order to offer the most complete assessment on the question to date, and to propose new hypotheses coherent with our current knowledge on Mourasuchus and on the feeding habits of crocodylomorphs. As a result, this study proposes that Mourasuchus was likely incapable of capturing and consuming large preys and specialized in eating small ones, such as mollusks, crustaceans and small fishes. The rostrum of Mourasuchus possibly evolved to cover the largest possible area, in order to be more efficient in the capture of large amounts of small preys. Whether Mourasuchus was capable to âselectâ the food from other material ingested with it is not yet known. In consequence, we suggest "gulp-feeding" to describe the proposed feeding habits of these animals. Mourasuchus was probably an inhabitant of quiet, shallow water bodies, where there were a broad range of habitats in which the preferred preys of this taxon dwelled. It is also proposed that the habit of Mourasuchus evolved from the durophagous habit proposed for many fossil caimanines. This hypothesis, however, has to be addressed by future studies.
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Data archiving statement:
Data for this study are available in the Dryad Digital Repository:
https://doi.org/10.5061/dryad.f4114kqVariation in preservation and sampling probability clouds our estimates of past biodiversity. The most extreme examples are LagerstÃtten faunas and floras. Although such deposits provide a wealth of information and represent true richness better than other deposits, they can create misleading diversity peaks because of their species richness. Here, we investigate how LagerstÃtten formations add to time series of vertebrate richness in the UK, Germany and China. The first two nations are associated with wellâstudied fossil records and the last is a country where palaeontology has a much shorter history; all three nations include noted LagerstÃtten in their fossil records. LagerstÃtten provide a larger proportion of China's sampled richness than in Germany or the UK, despite comprising a smaller proportion of its fossiliferous deposits. The proportions of taxa that are unique to LagerstÃtten vary through time and between countries. Further, in all regions, we find little overlap between the taxa occurring in LagerstÃtten and in âordinaryâ formations within the same time bin, indicating that LagerstÃtten preserve unusual faunas. As expected, fragile taxa make up a greater proportion of richness in LagerstÃtten than the remainder of the fossil record. Surprisingly, we find that LagerstÃtten account for a minority of peaks in the palaeodiversity curves of all vertebrates (18% in the UK; 36% in Germany and China), and LagerstÃtten count is generally not a good overall predictor of the palaeodiversity signal. Vastly different sampling probabilities through taxa, locations and time require serious consideration when analysing palaeodiversity curves.