Ben Creisler
Some new papers that may be of interest:
Tai Kubo (2019)
Biogeographical Network Analysis of Cretaceous Terrestrial Tetrapods: A Phylogeny-Based Approach.
Systematic Biology, syz024 (advance online publication)Â
Network methods are widely used to represent and analyse biogeography. It is difficult, however, to convert occurrence data of fossil vertebrates to a biogeographical network, as most species were known from a single locality. A new method for creating a biogeographical network that can incorporate phylogenetic information is proposed in this study, which increases the number of edges in the network of fossil vertebrates and enables the application of various network methods. Using ancestral state reconstruction via maximum parsimony, the method first estimates the biogeographical regions of all internal nodes of a given phylogeny using biogeographical information on the terminal taxa. Then, each internal node in the phylogenetic tree is converted to an edge in the biogeographical network that connects the region(s), if unambiguously estimated, of its two descendants. The new method was applied to phylogenetic trees generated by a birth-death model. Under all conditions tested, an average ofâ>â70% of the internal nodes in phylogenetic trees were converted into edges. Three network indicesâlink density, average link weight, and endemism indexâwere evaluated for their usefulness in comparing different biogeographical networks. The endemism index reflects the rate of dispersal; the other indices reflect nonbiogeographical parameters, the number of taxa and regions, which highlights the importance of evaluating network indices before applying them to biogeographical studies. Multiple Cretaceous biogeographical networks were constructed from the phylogenies of ïve tetrapod taxa: terrestrial crocodyliforms, terrestrial turtles, non-avian dinosaurs, avians, and pterosaurs. The networks of avians and pterosaurs showed similar topologies and a strong correlation, and unexpectedly high endemism indices. These similarities were probably a result of shared taphonomic biases (i.e., the LagerstÃtten effect) for volant taxa with fragile skeletons. The crocodyliform network was partitioned into the Gondwanan and Laurasian continents. The dinosaur network was partitioned into three groups of continents: (1) North America, Asia, and Australia; (2) Europe and Africa; (3) India, Madagascar, and South America. When Early and Late Cretaceous dinosaurs were analysed separately, the dinosaur networks were divided into (1) North America, Asia, and Australia; and (2) Europe, Africa, India, and South America for the Early Cretaceous and (1) North America, Asia, and Europe; (2) India, Madagascar, and South America for the Late Cretaceous. This partitioning of dinosaur and crocodyliform networks corroborates the results of previous biogeographical studies and indicates that the method introduced here can retrieve biogeographical signals from a source phylogeny when sufficient data are available for most targeted biogeographical regions.
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Ekaterina B. Pestchevitskaya, Irina M. Maschuk, Andrei O. Frolov, Svetlana A. Reshetova, Sofia M.Sinitsa & Anna G. Tyapkina (2019)
Biostratigraphy and palaeoenvironment of the Kulinda section (Transbaikalia, Russia) based on the Middle Jurassic palynology and macroflora.
Palaeoworld (advance online publication)
The palynological and macrofloral assemblages from the Lower Member of the Ukurey Formation have been studied based on the materials from a section exposed along the Kulinda Ravine (Olov Depression, Transbaikalia). This section is of special interest due to the occurrence of ornithischian dinosaurs. Based on palynological and palaeobotanical data, the studied deposits are dated as Middle Jurassic (Bathonian). Specific features of the palynological assemblages allow the correlation of the studied interval with Western Siberian palynozones calibrated by ammonite and foraminiferal successions. The resulting biostratigraphy suggests that the lower extent of the Ukurev Formation is not restricted to the Upper Jurassic as previously assumed. Lacustrine origin of the Lower Member of the Ukurev Formation is confirmed based on palaeoenvironmental analysis, showing changes of the terrestrial vegetation, associated with climatic conditions and fluctuations of the lake-level. Palaeobotanical and palynological data suggest that Middle Jurassic floras of eastern regions of Central Asia, southern regions of Siberia and Far East, as well as northern regions of China exhibit similar features.
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Leslie M.E. ManrÃquez, Ernesto L. Lavina, Roy A. FernÃndez, Cristine Trevisan, Marcelo A. Leppe (2019)
Campanian-Maastrichtian and Eocene stratigraphic architecture, facies analysis, and paleoenvironmental evolution of the northern Magallanes Basin (Chilean Patagonia).
Journal of South American Earth Sciences (advance online publication)
Highlights
Six third-order depositional sequences with abrupt limits (forced regression) were recognized during the Upper CretaceousâEocene.
Continental facies represent 40% and shallow marine environments 60% of the succession.
Each sequence is characterized by a Lowstand Systems Tract, a Transgressive Systems Tract, and, in one case, a Highstand Systems Tract.
The fossil record is diverse and abundant along the succession (invertebrates, vertebrates and plants).
Abstract
The stratigraphic architecture and environmental evolution of the Cerro Guido-Rio de las Chinas Valley Complex contains the upper Cretaceous to Eocene record of the Magallanes/Austral Basin, located in southernmost Chile. This retroarc foreland basin contains a significant record of early Cretaceous to Miocene biogeographic and environmental changes that occurred in high paleolatitudes after the break-up of Gondwana. Using 37 stratigraphic sections, we generated a 1390âm thick stratigraphic column, which was used to developed sedimentary facies and an analysis of sequence stratigraphy. Results show, in general, aggradation composed of six third-order depositional sequences each delimited by an erosive surface. A lowstand systems tract developed above each surface, represented by alluvial environments similar to braided fluvial systems, and coastal plain environments, with the development of meandering fluvial and lacustrine systems. Above the lowstand tract, the transgressive systems tract is composed of a shallow marine environment with foreshore, shoreface, and offshore systems. A highstand systems tract was observed in one sequence, and is represented by shallow marine facies. The extensive outcrop in the studied area contains a diverse and voluminous fossil record, containing fossilized invertebrates (bivalves, gastropods, bryozoans, and brachiopods), vertebrates (hadrosaurs, ornithischians, sauropods, theropods, birds, mammals, frogs, turtles, plesiosaurs, mosasaurs, and sharks), and plants (wood, leaves impressions, flowers, pollen, and spores). Thus, this study broadens the understanding of the South American-Antarctic connection during the late Cretaceous-Paleogene, through a diverse fossil record and study of the paleoenvironmental evolution of this high-latitude basin.
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Also:
Free pdf:
Gilad Bino, Richard T. Kingsford, Michael Archer, Joanne H. Connolly, Jenna Day, Kimberly Dias, David Goldney, Jaime Gongora, Tom Grant, Josh Griffiths, Tahneal Hawke, Melissa Klamt, Daniel Lunney, Luis Mijangos, Sarah Munks, William Sherwin, Melody Serena, Peter Temple-Smith, Jessica Thomas, Geoff Williams & Camilla Whittington (2019)
The platypus: evolutionary history, biology, and an uncertain future.Â
Journal of Mammalogy 100(2): 308â327
The platypus (Ornithorhynchus anatinus) is one of the worldâs most evolutionarily distinct mammals, one of five extant species of egg-laying mammals, and the only living species within the family Ornithorhynchidae. Modern platypuses are endemic to eastern mainland Australia, Tasmania, and adjacent King Island, with a small introduced population on Kangaroo Island, South Australia, and are widely distributed in permanent river systems from tropical to alpine environments. Accumulating knowledge and technological advancements have provided insights into many aspects of its evolutionary history and biology but have also raised concern about significant knowledge gaps surrounding distribution, population sizes, and trends. The platypusâ distribution coincides with many of Australiaâs major threatening processes, including highly regulated and disrupted rivers, intensive habitat destruction, and fragmentation, and they were extensively hunted for their fur until the early 20th century. Emerging evidence of local population declines and extinctions identifies that ecological thresholds have been crossed in some populations and, if threats are not addressed, the species will continue to decline. In 2016, the IUCN Red Listing for the platypus was elevated to "Near Threatened," but the platypus remains unlisted on threatened species schedules of any Australian state, apart from South Australia, or nationally. In this synthesis, we review the evolutionary history, genetics, biology, and ecology of this extraordinary mammal and highlight prevailing threats. We also outline future research directions and challenges that need to be met to help conserve the species.
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