[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

[dinosaur] New Konzhukovia species (temnospondyl) from Permian of South America + Early Triassic polar coprolites + more papers





Ben Creisler

bcreisler@gmail.com



Some recent non-dino papers:


Konzhukovia sangabrielensis 


Cristian Pereira Pacheco, Estevan Eltink, Rodrigo Temp Müller & Sérgio Dias-da-Silva (2016)

A new Permian temnospondyl with Russian affinities from South America, the new family Konzhukoviidae, and the phylogenetic status of Archegosauroidea

Journal of Systematic Palaeontology (advance online publication)

DOI:10.1080/14772019.2016.1164763

http: // www.tandfonline.com/doi/full/10.1080/14772019.2016.1164763


 

A new Permian temnospondyl from South America is described and considered to represent a new species – Konzhukovia sangabrielensis sp. nov. – of the genus Konzhukovia previously recorded exclusively from Russia. It consists of the anterior half and partial right side of the skull roof and palate. A comprehensive phylogenetic analysis was performed with several archegosauroids and other well-supported groups of temnospondyls in order to access the affinities of the new Brazilian species and test the monophyly of Archegosauroidea. Archegosauroidea was not recovered as a monophyletic group, comprising successive paraphyletic taxa. The only monophyletic group of ‘archegosauroids’ is the ‘Tryphosuchinae’ (in a sister-group relationship with Stereospondyli), composed of Tryphosuchus paucidens, Konzhukovia vetusta, K. tarda and K. sangabrielensis. As the diagnosis of T. paucidens is unclear and based on incomplete material, nested among three species of Konzhukovia, we consider this taxon to be a nomen dubium and purge it from the strict consensus tree. An alternative solution would be to erect a new taxonomic combination for T. paucidens. In order to solve these taxonomic problems, it is necessary to discover more complete material with a clear set of diagnostic characters, to either revalidate this taxon or provide a new combination for it. The phylogenetic results support the erection of a new family – Konzhukoviidae – to replace ‘Tryphosuchinae’ and accommodate Konzhukovia vetusta, K. tarda and K. sangabrielensis, the new Brazilian species basal to the Russian forms. An early diverging konzhukoviid in Gondwana leads to interesting insights regarding the evolution of the new family, stereospondyl origins, their early diversification and their palaeobiogeographical patterns of distribution.


http: // zoobank.org/urn:lsid:zoobank.org:pub:4772DC7E-C427-4F5F-89FD-9E68E3B0BFD5

===


Pavel P. Skutschas & Elizaveta A. Boitsova (2016)
Histology of sculptured cranial dermal bones of the stem salamander Kokartus honorarius (Amphibia: Caudata) from the Middle Jurassic of Kyrgyzstan.
Historical Biology (advance online publication
DOI:10.1080/08912963.2016.1171859
http: // www.tandfonline.com/doi/full/10.1080/08912963.2016.1171859


Kokartus honorarius from the Middle Jurassic (Bathonian) of Kyrgyzstan is one of the oldest and basalmost salamanders in the fossil record, and this taxon is useful for documenting a primitive caudate condition and patterns of character state transformations within Caudata. Here, we provide a histological analysis of its dermal bones based on two thin sections of a fragment of a sculptured dermal skull roof bone (squamosal?). The dermal bone histology of Kokartus is similar to that of basal crown-group tetrapods (e.g. temnospondyls, lepospondyls and seymouriamorphs) in the following features: the presence of basic pattern of organisation of dermal bones (diploë structure); the cancellous middle region occupies larger space than the compact cortices; active remodelling with the formation of numerous erosion bays and secondary osteons; high number of vascular canals with the formation a dense vascular network (= ‘rete vasculosum’); and parallel-fibred bone is a dominant type of primary bone matrix. Crown-group salamanders retained the diploë structure, but demonstrate features of simplification (in comparison with Kokartus): absence of pronounced sculpture, lower degree of vascularisation and lower degree of remodelling. The simplification of the histological structure is a derived feature for the Caudata which appeared during the transition from stem-group to crown-group salamanders.


===


Grzegorz Niedźwiedzki, Piotr Bajdek, Krzysztof Owocki & Benjamin P. Kear (2016)

An Early Triassic polar predator ecosystem revealed by vertebrate coprolites from the Bulgo Sandstone (Sydney Basin) of southeastern Australia.

Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)

doi:10.1016/j.palaeo.2016.04.003

http: // www.sciencedirect.com/science/article/pii/S0031018216300578

 

Highlights


First vertebrate coprolite record from Early Triassic deposits of the Sydney Basin in Australia.

Phosphatic groundmass indicates a previously undocumented vertebrate predator diversity including large freshwater fishes, variously sized temnospondyls, and archosauriforms or other apex carnivores.

Rare Earth Element (REE) analyses confirm burial within coastal fluvial sediments during early diagenesis.

Reconstructed eco-community structure incorporates abundant aquatic predators and evidence of large amniotes that inhabited an Early Triassic near polar environment.


Abstract


Vertebrate trace fossils often provide a measure of cryptic biodiversity, and are especially pertinent when skeletal remnants are exceptionally rare. The Lower Triassic (lower Olenekian) Bulgo Sandstone at Long Reef in the Sydney Basin of southeastern Australia constitutes just such a deposit, having yielded isolated bones of giant capitosaurian temnospondyls and proterosuchid archosauriforms, together with abundant coprolites that are geochemically rich in elemental phosphate and carbon denoting vertebrate predators. Microstructural analysis of these preserved droppings reveals occasional bone fragments, fish scales, insect cuticles, plant material and bacterial traces (pseudomorph voids), as well as silicate mineral particles. REE concentrations indicate that burial and early diagenesis occurred explicitly within fluvial sediments. Furthermore, external morphological characterization permits attribution of spiral coprolites to chondrichthyan or osteichthyan fishes, polygonal, ovoid–spherical and typically flattened feces to temnospondyls, and conspicuously large cylindrical droppings to archosauriforms or other amniote apex predators. Collectively, the Bulgo Sandstone coprolite assemblage thus offers new insights into ecosystem structure and palaeoenvironment in what was an earliest Triassic near polar setting. Such data compliments the documented skeletal record, but indicates a greater range of aquatic and possibly terrestrial carnivores — the latter being enigmatically sparse in the Australian Triassic and yet detected here via the hitherto underexplored trace fossil evidence of their ecological presence.


==



Alyson M. Thibodeau, Kathleen Ritterbush, Joyce A. Yager, A. Joshua West, Yadira Ibarra, David J. Bottjer,  William M. Berelson, Bridget A. Bergquist & Frank A. Corsetti (2016)

Mercury anomalies and the timing of biotic recovery following the end-Triassic mass extinction.

Nature Communications 7, Article number: 11147

doi:10.1038/ncomms11147

http: // www.nature.com/ncomms/2016/160406/ncomms11147/full/ncomms11147.html



The end-Triassic mass extinction overlapped with the eruption of the Central Atlantic Magmatic Province (CAMP), and release of CO2 and other volcanic volatiles has been implicated in the extinction. However, the timing of marine biotic recovery versus CAMP eruptions remains uncertain. Here we use Hg concentrations and isotopes as indicators of CAMP volcanism in continental shelf sediments, the primary archive of faunal data. In Triassic–Jurassic strata, Muller Canyon, Nevada, Hg levels rise in the extinction interval, peak before the appearance of the first Jurassic ammonite, remain above background in association with a depauperate fauna, and fall to pre-extinction levels during significant pelagic and benthic faunal recovery. Hg isotopes display no significant mass independent fractionation within the extinction and depauperate intervals, consistent with a volcanic origin for the Hg. The Hg and palaeontological evidence from the same archive indicate that significant biotic recovery did not begin until CAMP eruptions ceased.