Some recent non-dino papers not yet mentioned:
Xufeng Hu, Lu Li, Hui Dai, Ping Wang, Eric Buffetaut, Guangbiao Wei, Can Xiong & HaiyanTong (2020)
Turtle remains from the Middle Jurassic Xintiangou Formation of Yunyang, Sichuan Basin, China.
Annales de PalÃontologie 102440
doi: https://doi.org/10.1016/j.annpal.2020.102440 https://www.sciencedirect.com/science/article/abs/pii/S075339692030063X
Three turtle shells from the Middle Jurassic Xintiangou Formation of Yunyang (Chongqing, China) are described and assigned to Xinjiangchelyidae (Testudines: Eucryptodira). This is the first report of turtle remains from the Xintiangou Formation, Sichuan Basin and represents the oldest known Xinjiangchelyidae. The assemblage includes two taxa, Protoxinjiangchelys sp. and Xinjiangchelyidae indet. This discovery extends the stratigraphical distribution of Xinjiangchelyidae and improves our knowledge about the early evolution of that family. It demonstrates that by the Middle Jurassic, at the time of deposition of the Xintiangou Formation, the group was already diversified in the Sichuan Basin.
Teiid lizards are well represented in the fossil record and are common components of modern ecosystems in North and South America. Many fossils were referred to the cnemidophorine teiid group (whiptails, racerunners and relatives), particularly from North America. However, systematic interpretations of morphological features in cnemidophorines were hampered by the historically problematic taxonomy of the clade, and the biogeography and chronology of cnemidophorine evolution in North America is poorly understood from the fossil record. Few fossil cnemidophorines were identified with an apomorphy-based diagnosis, and there are almost no fossil cnemidophorines that could be used to anchor node calibrations. Here, I describe a cnemidophorine from the Miocene Ogallala Group of Nebraska and diagnose the fossil using apomorphies. In that process, I clarify the systematic utility of several morphological features of cnemidophorine lizards. I refer the fossil to the least inclusive clade containing Aspidoscelis, Holcosus and Pholidoscelis. The most conservative minimum age of the locality of the fossil is a fission-track date of 6.3 Ma, but mammal biochronology provides a more refined age of 9.4 Ma, which can be used as a minimum age for the crown cnemidophorine clade in divergence time analyses. The fossil indicates that a cnemidophorine lineage that does not live in Nebraska today inhabited the area during the Miocene. I refrain from naming a new taxon pending discovery of additional fossil material of the lineage to which the fossil belonged.
Takaki Kurita, Yosuke Kojima, Mohamad Yazid Hossman & Kanto Nishikawa (2020)
Phylogenetic position of a bizarre lizard Harpesaurus implies the co-evolution between arboreality, locomotion, and reproductive mode in Draconinae (Squamata: Agamidae).
Systematics and Biodiversity (advance online publication)
doi: https://doi.org/10.1080/14772000.2020.1795741 https://www.tandfonline.com/doi/full/10.1080/14772000.2020.1795741
Viviparous reproduction has evolved independently more than 100 times in the evolutionary history of Squamata (lizards and snakes). Adaptation to cold climates is the dominant hypothesis explaining shifts to viviparity, but viviparous species are also present in the tropical lowlands, implying the presence of other factors that may also promote the evolution of viviparity. For example, the tropical Asian/Oceanian subfamily, Draconinae, includes two viviparous genera (Cophotis and Harpesaurus). However, one of them, Harpesaurus, is extremely rare, making it difficult to study aspects of their ecology or evolution. We managed to collect a H. borneensis, and this provided an opportunity to address the evolution of viviparity in draconine lizards. Based on a new molecular phylogenetic hypothesis, including all viviparous groups in Draconinae, we infer that viviparity has evolved twice within the subfamily. Ancestral state reconstruction analyses indicated that shifts to viviparity were preceded by the evolution of arboreality and slow-moving locomotion. Our analysis strongly suggests evolutionary correlations between habitats, locomotion, and reproductive modes. Taken together, these results suggest that the use of arboreal habitats and slow locomotion facilitated the evolution of viviparity in these tropical/subtropical lizards. Arboreal, slow-moving species are considered to rely more on crypsis in predator avoidance rather than fleeing. Therefore, we propose that such species are relatively insusceptible to the concomitant cost of viviparity: reduced locomotive ability and increased risk of predation during pregnancy. We also describe and discuss the unique behaviours of H. borneensis.
The Lowerverse local fauna of West Texas, USA, preserves a rare, early Campanian assemblage of microvertebrates from Laramidia. The recovery of 137 fragmentary specimens reveals that albanerpetontids were locally abundant here and also widespread throughout much of the Western Interior of North America by early Campanian time. Both gracile- and robust-snouted species are represented within the assemblage. Among these, the occurrence of Albanerpeton nexuosum is consistent with its occurrence in paracontemporaneous deposits elsewhere in the Western Interior. The referral of two specimens to Albanerpeton sp., cf. A. galaktion strongly suggests that this long-lived taxon was far more widespread during the early Campanian than previously known and its likely occurrence in West Texas represents a significant geotemporal range extension for the species. However, Albanerpeton gracile is seemingly restricted to Judithian 'age' deposits in North America and was not identified at Lowerverse. The Lowerverse assemblage supports the current paradigm involving the occurrence of these three named albanerpetontids during middle CampanianâMaastrichtian time in the Western Interior of North America.
We report the first Permian ichnofauna from the Zat Valley in Morocco.
The ichnoassemblage includes protostomian traces and tetrapods tracks.
Tracks are described using photogrammetric imaging techniques.
Palaeoenvironment evolved from braided/meandering systems to alluvial floodplains.
A new ichnofauna from the Permian of Morocco is described in details: it is the first Palaeozoic ichnofauna from the Zat Valley in Marrakech High Atlas. The new tracksite was found in the Tighdouine region, in the middle-upper Permian of the Cham-el-Houa Siltstone Formation. An abundant and diverse ichnoassemblage composed of both protostomian (probably arthropods and annelids) traces and vertebrate tracks is recorded. The presence of protostomian burrows and traceways, associated with tetrapod tracks corresponds to the Scoyenia ichnofacies. Protostomian traces are ascribed to Diplichnites gouldi, Diplopodichnus biformis, Scoyenia cf. gracilis and Spongeliomorpha carlsbergi. Tetrapod tracks include more than 70 tracks attributed to Amphisauropus, Erpetopus, Hyloidichnus, Characichnos, and indeterminate tracks. The co-occurrence of tetrapod tracks (both walking and swimming tracks), protostomian traces, mudcracks, ripple marks, as well as the lithological features of the track-bearing levels, indicate regularly inundated depositional environments during periods of high discharge under a local seasonal climate. A sedimentological analysis shows that the depositional environments evolved from braided-meandering systems to alluvial floodplains. The track-bearing surfaces are mainly preserved in crevasse splays, levees and pond deposits. This newly discovered ichnofauna helps to better reconstruct the palaeoenvironments of the Marrakech High Atlas in Morocco during the Permian, and enlarges the palaeogeographic distribution of important ichnotaxa.
Fortuna Alla, Korzhenkov Andrew & Abdieva Svetlana (2020)
Mesozoic and Cenozoic fauna in the territory the Northern Tien Shan.
Bulletin of the Institute of Seismology of the National Academy of Sciences of the Kyrgyz Republic 1(15): 91-105 (in Russian)https://elibrary.ru/item.asp?id=42847891
The paper presents the material on the fauna of fossil remains, which were found in the Mesozoic and Cenozoic sediments of the Northern Tien Shan.
Isadora da Costa, LÃlian Paglarelli Bergqvist, Caio CÃsar Rangel & Fernando Henrique de Souza Barbosa (2020)
Earliest evidence of bone lesion in a metatherian.
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2020.1802446 https://www.tandfonline.com/doi/full/10.1080/08912963.2020.1802446
Although metatherians are known since Early Cretaceous, there is little evidence of bone lesions in this extremely diverse mammalian clade. Here, we report an asymptomatic and benign condition named torus mandibularis in an incomplete right dentary assigned to Patene simpsoni, a basal sparassodont from the early Eocene of SÃo JosÃ de ItaboraÃ Basin, Brazil. This report represents the oldest evidence of bone lesion in a Metatheria, as well as the first occurrence of torus mandibularis in a nonhuman fossil. The proposed diagnosis was based on location and external appearance of the bone overgrowth.
Edana Lord, Nicolas Dussex, Marcin Kierczak, David DÃez-del-Molino, Oliver A. Ryder, David W.G. Stanton, M. Thomas P. Gilbert, FÃtima SÃnchez-Barreiro, Guojie Zhang, Mikkel-Holger S. Sinding, Eline D. Lorenzen, Eske Willerslev, Albert Protopopov, Fedor Shidlovskiy, Sergey Fedorov, HervÃ Bocherens, Senthilvel K.S.S. Nathan, Benoit Goossens, Johannes van der Plicht, Yvonne L. Chan, Stefan Prost, Olga Potapova, Irina Kirillova, Adrian M. Lister, Peter D. Heintzman, Joshua D. Kapp, Beth Shapiro, Sergey Vartanyan, Anders GÃtherstrÃm & Love DalÃn (2020)
Pre-extinction Demographic Stability and Genomic Signatures of Adaptation in the Woolly Rhinoceros.
Current Biology (advance online publication)
Complete genome and mitogenome analysis of the extinct woolly rhinoceros
Demographic analysis suggests stable population size until close to extinction
No increased inbreeding or reduced genomic diversity coinciding with human arrival
Woolly rhinoceros had genetic adaptations to arctic climate
Ancient DNA has significantly improved our understanding of the evolution and population history of extinct megafauna. However, few studies have used complete ancient genomes to examine species responses to climate change prior to extinction. The woolly rhinoceros (Coelodonta antiquitatis) was a cold-adapted megaherbivore widely distributed across northern Eurasia during the Late Pleistocene and became extinct approximately 14 thousand years before present (ka BP). While humans and climate change have been proposed as potential causes of extinction, knowledge is limited on how the woolly rhinoceros was impacted by human arrival and climatic fluctuations. Here, we use one complete nuclear genome and 14 mitogenomes to investigate the demographic history of woolly rhinoceros leading up to its extinction. Unlike other northern megafauna, the effective population size of woolly rhinoceros likely increased at 29.7 ka BP and subsequently remained stable until close to the speciesâ extinction. Analysis of the nuclear genome from a â18.5-ka-old specimen did not indicate any increased inbreeding or reduced genetic diversity, suggesting that the population size remained steady for more than 13 ka following the arrival of humans . The population contraction leading to extinction of the woolly rhinoceros may have thus been sudden and mostly driven by rapid warming in the BÃlling-AllerÃd interstadial. Furthermore, we identify woolly rhinoceros-specific adaptations to arctic climate, similar to those of the woolly mammoth. This study highlights how species respond differently to climatic fluctuations and further illustrates the potential of palaeogenomics to study the evolutionary history of extinct species.
Climate change, not hunters, may have killed off woolly rhinos
Studies of biodiversity through deep time have been a staple for biologists and palaeontologists for over 60 years. Investigations of species richness (diversity) revealed that at least five mass extinctions punctuated the last half billion years, each seeing the rapid demise of a large proportion of contemporary taxa. In contrast to diversity, the response of morphological diversity (disparity) to mass extinctions is unclear. Generally, diversity and disparity are decoupled, such that diversity may decline as morphological disparity increases, and vice versa. Here, we develop simulations to model disparity changes across mass extinctions using continuous traits and birthâdeath trees. We find no simple null for disparity change following a mass extinction but do observe general patterns. The range of trait values decreases following either random or traitâselective mass extinctions, whereas variance and the density of morphospace occupation only decline following traitâselective events. General trends may differentiate random and traitâselective mass extinctions, but methods struggle to identify trait selectivity. Longâterm effects of mass extinction trait selectivity change support for phylogenetic comparative methods away from the simulated Brownian motion towards OrnsteinâUhlenbeck and Early Burst models. We find that morphological change over mass extinction is best studied by quantifying multiple aspects of morphospace occupation.