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Ueekenkcoracias tambussiae gen. et sp. nov.
Here we present the first record of a stem-Coracii outside the Holarctic region, found in the early Eocene of Patagonia at the Laguna del Hunco locality. Ueekenkcoracias tambussiae gen. et sp. nov. consists of an incomplete right hind limb that presents the following combination of characters, characteristic of Coracii: relatively short and stout tibiotarsus, poorly developed crista cnemialis cranialis, short and wide tarsometatarsus, with the tuberositas m. tibialis cranialis located medially on the shaft, and curved and stout ungual phalanges. Although the presence of a rounded and conspicuous foramen vasculare distale and the trochlea metatarsi II strongly deflected medially resemble Primobucconidae, a fossil group only found in the Eocene of Europe and North America, our phylogenetic analysis indicates the new taxon is the basalmost known Coracii. The unexpected presence of a stem-Coracii in the Eocene of South America indicates that this clade had a more widespread distribution than previously hypothesized, already extending into the Southern Hemisphere by the early Eocene. Ueekenkcoracias tambussiae represents new evidence of the increasing diversity of stem lineages of birds in the Eocene. The new material provides novel morphological data for understanding the evolutionary origin and radiation of rollers and important data for estimates of the divergence time of the group.
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Simple Summary
Some of the earliest studies using molecular data to resolve evolutionary history separated birds into three main groups: Paleognathae (ostriches and allies), Galloanseres (ducks and chickens), and Neoaves (the remaining ~95% of avian species). The early evolution of Neoaves, however, has remained challenging to understand, even as data from whole genomes have become available. We have recently proposed that some of the conflicts among recent studies may be due to the type of genomic data that is analyzed (regions that code for proteins versus regions that do not). However, a rigorous examination of this hypothesis using coding and non-coding data from the same genomic regions sequenced from a relatively large number of species has not yet been conducted. Here we perform such an analysis and show that data type does influence the methods used to infer evolutionary relationships from molecular sequences. We also show that conducting analyses using models of sequence evolution that were chosen to minimize reconstruction errors result in coding and non-coding trees that are much more similar, and we add to the evidence that non-coding data provide better information regarding neoavian relationships. While a few relationships remain problematic, we are approaching a good understanding of the evolutionary history for major avian groups.
Abstract
The phylogeny of Neoaves, the largest clade of extant birds, has remained unclear despite intense study. The difficulty associated with resolving the early branches in Neoaves is likely driven by the rapid radiation of this group. However, conflicts among studies may be exacerbated by the data type analyzed. For example, analyses of coding exons typically yield trees that place Strisores (nightjars and allies) sister to the remaining Neoaves, while analyses of non-coding data typically yield trees where Mirandornites (flamingos and grebes) is the sister of the remaining Neoaves. Our understanding of data type effects is hampered by the fact that previous analyses have used different taxa, loci, and types of non-coding data. Herein, we provide strong corroboration of the data type effects hypothesis for Neoaves by comparing trees based on coding and non-coding data derived from the same taxa and gene regions. A simple analytical method known to minimize biases due to base composition (coding nucleotides as purines and pyrimidines) resulted in coding exon data with increased congruence to the non-coding topology using concatenated analyses. These results improve our understanding of the resolution of neoavian phylogeny and point to a challenge--data type effects--that is likely to be an important factor in phylogenetic analyses of birds (and many other taxonomic groups). Using our results, we provide a summary phylogeny that identifies well-corroborated relationships and highlights specific nodes where future efforts should focus.
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Rageryx schmidi gen. et sp. nov.Â
Krister T. SMITH & AgustÃn SCANFERLA (2021)
A nearly complete skeleton of the oldest definitive erycine boid (Messel, Germany).
In STEYER J.-S., AUGÃ M. L. & MÃTAIS G. (eds), Memorial Jean-Claude Rage: A life of paleo-herpetologist.
Geodiversitas 43(1): 1-24
doi:
https://doi.org/10.5252/geodiversitas2021v43a1https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/43/1A nearly complete skeleton of an erycine boid is described from the Ypresian-Lutetian (early-middle Eocene) site of Messel, Germany, for which we propose the name Rageryx schmidi n. gen., n. sp. The animal had a total length of c. 52 cm, with c. 258 vertebrae. In skull proportions it is similar to ungaliophiine boids, especially Ungaliophis, and to Tropidophis. The proportions and distinctive accessory processes of the distal caudal vertebrae that are common to all living erycine boids are present in the specimen, although the processes are not as elaborate as in many extant species. The premaxilla was not protruded to form a wedge-shaped snout, and the nasofrontal joint does not appear to show any special buttressing, unlike in many burrowing snake species. Furthermore, the inner ear lacks adaptations to an actively burrowing mode of life. We conclude that the animal, while it was probably secretive, was not fossorial. Phylogenetic analyses using maximum parsimony and Bayesian inference place Rageryx schmidi n. gen., n. sp. unambiguously on the stem of the North American clade (Lichanura + Charina). If this relationship is accurate, it provides further support for a common Euro-American squamate fauna in the early Eocene. The majority of known Messel snake taxa are small-bodied with a small gape, suggesting that such forms may have played a greater role in the early evolutionary radiation of Booidea than their present diversity would suggest.
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Marine reptiles from the Upper Jurassic of Central Europe are rare and often fragmentary, which hinders their precise taxonomic identification and their placement in a palaeobiogeographic context. Recent fieldwork in the Kimmeridgian of KrzyÅanowice, Poland, a locality known from turtle remains originally discovered in the 1960s, has reportedly provided additional fossils thought to indicate the presence of a more diverse marine reptile assemblage, including giant pliosaurids, plesiosauroids, and thalattosuchians. Based on its taxonomic composition, the marine tetrapod fauna from KrzyÅanowice was argued to represent part of the "Matyja-Wierzbowski Line"--a newly proposed palaeobiogeographic belt comprising faunal components transitional between those of the Boreal and Mediterranean marine provinces. Here, we provide a detailed re-description of the marine reptile material from KrzyÅanowice and reassess its taxonomy. The turtle remains are proposed to represent a "plesiochelyid" thalassochelydian (Craspedochelys? sp.) and the plesiosauroid vertebral centrum likely belongs to a cryptoclidid. However, qualitative assessment and quantitative analysis of the jaws originally referred to the colossal pliosaurid Pliosaurus clearly demonstrate a metriorhynchid thalattosuchian affinity. Furthermore, these metriorhynchid jaws were likely found at a different, currently indeterminate, locality. A tooth crown previously identified as belonging to the thalattosuchian Machimosaurus is here considered to represent an indeterminate vertebrate. The revised taxonomy of the marine reptiles from KrzyÅanowice, as well as the uncertain provenance of the metriorhynchid specimen reported from the locality, cast doubt on the palaeobiogeographic significance of the assemblage.