XING Lida, LOCKLEY, Martin G., YOU Hailu, PENG Guangzhao, TANG Xiang, RAN Hao, WANG Tao, HU Jian, PERSONS, W. Scott (2016)
Early Jurassic sauropod tracks from the Yimen Formation of Panxi region, Southwest China: Ichnotaxonomy and potential trackmaker.
Geological Bulletin of China 35(6): 851-855
Dinosaur track and bone records often occur at different locations. However, a few formations show a close correspondence between bones and tracks that correspond to likely trackmakers. In this paper, the authors report sauropod tracks (Brontopodus) in very close geographic and stratigraphic proximity to the type locality of the eusauropod Tonganosaurus hei in the middle-upper parts of the Lower Jurassic Yimen Formation in Tongbao Village, Huili County, Panxi region of Sichuan Province. This Huili track-trackmaker correlation is possibly existent, but still needs more evidence to confirm. As the first Jurassic sauropod tracks found in the Panxi region, the Tongbao Brontopodus tracks have provided evidence indicating coexistence of primitive sauropod and basal sauropodomorphs in Southwest China during Early Jurassic.
Eleanor E. Gardner, Sally E. Walker & Lytt I. Gardner (2016)
Palaeoclimate, environmental factors, and bird body size: a multivariable analysis of avian fossil preservation.
Earth-Science Reviews (advance online publication)
For this study, we abstracted data on 693 avian fossil specimens from 398 publications to determine preservation biases in the avian fossil record. Our results show that dissociated wing and leg bones are the most commonly preserved avian skeletal elements and they are preferentially preserved in environments of high erosion and reworking potential—notably continental shelf marine environments. Using bivariate descriptive displays and multivariable regression analyses, we investigated the trends and associations between well-preserved avian specimens (i.e., fully- or partially-articulated) and a variety of taphonomic factors, including depositional environment, body size, and palaeoclimate. The regression model shows that well-preserved specimens are independently associated with depositional environments of low reworking potential commensurate with low energy systems, warm and humid climates, and smaller bird body size. Our results also indicate that fossils of smaller birds are less common than those of larger birds, but they are more often well-preserved. Bivariate analyses revealed that five times as many articulated specimens are found in warm and humid climates as in cool or dry climates, and this association persists in the multivariable regression model. Warm climates, the strongest predictor of better skeletal preservation, may be underestimated as a source of taphonomic bias in the avian fossil record, possibly because of the indirect nature of climate effects. Rapid burial events, such as volcanic ash accumulations and mudflows, are recognised for their influence on preservation, but climate-related storm events may be more important to avian taphonomy than previously understood. Our analyses indicate that geologic processes leading to high quality preservation of avian fossils are closely associated with climate. Additional studies, based both on fossils and modern taphonomic experiments, with improved collection of climate-related data, are needed to advance our understanding of avian taphonomy.
Alexander O. Averianov, Igor G. Danilov, Pavel P. Skutschas, Ivan T. Kuzmin, Hans-Dieter Sues, and Gareth Dyke (2016)
The Late Cretaceous vertebrate assemblages of western Kazakhstan.
in Khosla, A. and Lucas, S.G., eds., 2016, Cretaceous Period: Biotic Diversity and Biogeography. New Mexico Museum of Natural History and Science Bulletin 71: 5-17.
Late Cretaceous vertebrates are known from the Turonian Zhirkindek and Santonian Bostobe formations in the western Kazakhstan region northeast of the Aral Sea. The Zhirkindek vertebrate assemblage resembles that known from the Turonian Bissekty Formation of the Kyzylkum Desert, Uzbekistan, because of the presence of the rhinobatoid ray Myledaphus tritus that has unsculptured teeth and the prevalence of gars (Lepisosteidae). The latter apparently became locally extinct during the Coniacian. The Santonian Bostobe and Yalovach (Tajikistan) formations are similar in that they share the presence of the more derived rhinobatoid, Myledaphus glickmani, that has sculptured teeth. The Zhirkindek assemblage is also noteworthy for the presence of basal neoceratopsians, whereas the basal ceratopsid or stem-ceratopsid Turanoceratops tardabilis is present in the Bissekty Formation and possibly in the Santonian Bostobe and Syuk Syuk formations of southern Kazakhstan. The ornithopods from the Bostobe Formation, the basal hadrosauroid Batyrosaurus rozhdestvenskyi and the basal lambeosaurine Aralosaurus tuberiferus, are more derived than the basal hadrosauroid Levnesovia transoxiana known from the Bissekty Formation. The mammalian assemblage of the Bostobe Formation is dominated by zhelestid stemplacentals also similar to those from the Bissekty Formation.
Asher J. Lichtig and Spencer G. Lucas (2016)
Cretaceous nonmarine turtle biostratigraphy and evolutionary events.
in Khosla, A. and Lucas, S.G., eds., 2016, Cretaceous Period: Biotic Diversity and Biogeography. New Mexico Museum of Natural History and Science Bulletin 71: 185-194
A biostratigraphic organization of the Cretaceous nonmarine turtle record provides valuable insight into turtle evolutionary events. Five biostratigraphic datums based on Cretaceous turtle distribution are identified: Barremian, Aptian/Albian, Albian/Cenomanian, Turonian, Santonian/Campanian and the K/T boundary. The Barremian encompasses the lowest occurrences of Lindholemydidae, Dortokidae, Podocnemoidea, Nanhsiungchelydae, and Trionychidae, marking a major increase in turtle diversity. The Aptian/Albian datum is marked by the lowest occurrences of Bothremydidae and Baenidae. The Albian/Cenomanian datum is the highest occurrence of Xinjiangchelyidae, Araripemydidae, and Euraxemydidae. The Turonian datum is marked by the first occurrence of Macrobaenidae and Chelydridae in North America. The Santonian/Campanian datum is marked by the lowest occurrence of Compsemydidae. Further, this is the highest occurrence of Sinemydidae. The K/Pg datum is marked by the highest occurrences of Nanhsiungchelydae, Kallokibotionidae, and Solemydidae. The dispersal of bothremydids to South America and Africa is hypothesized to be the result of a lowering of global sea level. This may also explain the immigration of trionychoideans into North America at a similar time. Further, macrobaenid appearance in North America also falls within the temporal uncertainty of the bothremydid and trionychoidean migrations, so these may represent one event.
On a less "sound science" note:
Shonisaurus-shifting, artistic Kraken returns...
Book chapter links:
Mark A. S. McMenamin (2016)
In: Dynamic Paleontology: 131-158
What killed the giant ichthyosaurs of Berlin-Ichthyosaur State Park in Nevada? The leading hypothesis is that a giant octopus-like cephalopod attacked and killed the Shonisaurus ichthyosaurs and dragged their corpses to the Triassic sea floor. The Triassic Kraken hypothesis has survived all tests to date, and currently stands alone as the best explanation for the strange collection of large ichthyosaur bones at Berlin-Ichthyosaur State Park, Nevada.
Mark A. S. McMenamin (2016)
In: Dynamic Paleontology: 159-179
What did the giant Shonisaurus ichthyosaurs eat? Analysis of their coprolites indicates that shonisaurs fed on coelacanths, a fish type that is often associated with deeper water habitats. It is possible to make comparisons between Triassic and modern deep water, open ocean communities. Environmental convergence may be measured in tetrapod:cephalopod:fish trophic webs by means of the corrected connectance (Cc) parameter.