Search

The non-marine bivalve Ferganoconcha occurred widely in palaeolakes in the high-middle latitude of northern China, Siberia and Central Asia during the Early and Middle Jurassic and was an important member of these lacustrine ecosystems. The diagnostic features and phylogenetic position of Ferganoconcha are still under debate. Here, based on nearly one hundred of Ferganoconcha specimens from the lacustrine and fluvial facies of the Junggar Basin in northwestern China, it is clearly shown that its most important distinctive features are the thin and flatted to weakly inflated shell covered with wrinkled ornament and the ligament is well-developed. This kind of shell indicate that the Ferganoconcha is a weak suspension feeder, burrowing rapidly and living in fine-soft substrata of the 'low energy' environments. In addition, we conclude that the dispersal pattern of the Ferganoconcha generally followed the cool to temperate and humid paleoclimate zone in northern China during the Early to Middle Jurassic, making the genus a possible palaeclimatic indicator. [ABSTRACT FROM AUTHOR]

The new genus and species, Jurassephemera zhangi gen. et sp. nov., belonging to the extinct family Sharephemeridae (Ephemeroptera: Mesephemeroidea), is established from the late Early Jurassic interval of the Shiti Formation of Guangxi Zhuang Autonomous Region, South China. The new genus and species is characterised by its moderate size; small head with reduced compound eyes; body with ten abdominal segments; round-triangular forewing shape; vein R dividing three times, forming five veinlets and three triads; veins MA, MP, and CuA straight, all basally forking once with single triads between; crossveins well developed; and hind wing oval, much smaller than forewing, with veins generally radial and single. SEM observations also reveal that crossveins are much more developed than previously recognised under optical illumination. The forewing venation of all sharephemerid genera is compared. The first report of this family in China herein increases the diversity and palaeogeographic distribution of Sharephemeridae. [ABSTRACT FROM AUTHOR]

A distinct coal break occurs widely in the late Early Jurassic in Central Asia, the cause of which, however, is still debated largely due to the uncertainty of its age constraint. In the Junggar Basin of northwestern China, this coal break coincides with the Sangonghe Formation, which is well exposed along the basin margins, and is mainly composed of lacustrine deposits rich in a variety of fossils, including plants, pollens and spores, bivalves, clam shrimps, insects and some vertebrates. Here we name them as the Sangonghe biota and review their biostratigraphic framework. The Sangonghe biota constrains the Sangonghe Formation to the late Pliensbachian to the early Aalenian. Abundant thermophilous plants and Classopollis, together with frequent occurrences of red beds and carbonate nodules in the middle part of the Sangonghe Formation, are indicative of an arid climate in Central Asia at that time. This arid interlude should be responsible for the coal break, which may be related to the global warming in the early Toarcian. However, more precise dating evidence is needed to substantiate this. [ABSTRACT FROM AUTHOR]

As an important combination of behaviour and pattern in animals to resemble benign objects, biolog ical mimesis can effectively avoid the detection of their prey and predators. It at least dates back to the Permian in fossil records. The recognition of mimesis within fossil, however, might be subjective and lack quantitative analysis being only based on few fossils with limited information. To compensate for this omission, we propose a new method using a Siamese network to measure the dissimilarity between hypothetical mimics and their models from images. It generates dissimilarity values between paired images of organisms by extracting feature vectors and calculating Euclidean distances. Additionally, the idea of 'transfer learning' is adopted to fine-tune the Siamese network, to overcome the limitations of available fossil image pairs. We use the processed Totally-Looks-Like, a large similar image data set, to pretrain the Siamese network and fine-tune it with a collected mimetic-image data set. Based on our results, we propose two recommended image dissimilarity thresholds for judging the mimicry of extant insects (0–0.4556) and fossil insects (0–0.4717). Deep learning algorithms are used to quantify the mimicry of fossil insects in this study, providing novel insights into exploring the early evolution of mimicry. [ABSTRACT FROM AUTHOR]

The second species of Saltissus, as the first mimarachnid planthopper, is herein described from the upper Weald Clay Formation, Smokejacks brickworks, England. Saltissus fennahi Luo, Liu et Jarzembowski sp. nov. can be distinguished from the type species Saltissus eskovi Shcherbakov, 2007 due to the tegmen being more than 20 mm long, stem Pc+CP merged with margin at less than 1/10th of tegmen length, stem ScP+R forked beyond the fusion of Pcu+A1, and branch A1 curved strongly at base. The distribution and tegminal colour pattern of Mimarachnidae are briefly discussed. [ABSTRACT FROM AUTHOR]