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Preservation of soft parts (collagen fibres, blood vessels and cells) in extinct vertebrates is rare and usually limited to fossilized bone and cartilage. Well-preserved coarse collagenous fibre bundles embedded in a mineralized matrix of tendons, as well as numerous hollow, tubular structures consistent morphologically with fibril bundles, blood vessels and associated cells, were identified in ossified tendons of Late Cretaceous ornithischians from North America and Central East Asia. Detailed, high-accuracy imaging, along with spectroscopic characterization of those fibrous structures and comparison with ossified tendons of modern-day turkeys, support the proposition that physiologically driven tendon ossification is common for avians and non-avian dinosaurs. The examined soft parts were preserved through the pathway of iron-induced crosslinking and alumino-silification, documenting a variety of pathways for the preservation of soft parts, depending on the burial environment. For the first time, the structure of dinosaur fossilized tendons is analysed in detail, revealing shared histogenetic principles with modern birds and the nature of preservation. [ABSTRACT FROM AUTHOR]

Currently, the validity of many nominal bivalve species of the genus Corbicula endemic to the Russian Far East and South Korea needs a critical reassessment. In this study, we clarify the taxonomic status of Corbicula species of this area based on a combination of molecular genetic, conchological and anatomical data. According to our results, four Corbicula lineages, corresponding to the nominal species Corbicula japonica , Corbicula elatior , Corbicula leana and Corbicula fluminea , can be delineated in samples collected in the Primorye and Khabarovsk regions of Russia and South Korea. Two species endemic to the Russian Far East (i.e. Corbicula finitima and Corbicula lindholmi) are considered here as junior synonyms of the species C. japonica , which is widely distributed in estuarine habitats around the Japanese Archipelago, Sakhalin Island, southern Kurile Islands, Primorye and Khabarovsk regions, Korean Peninsula and China. Three nominal species described from the Lower Amur basin (Corbicula amurensis , Corbicula nevelskoyi and Corbicula sirotskii) appeared to be synonyms of C. elatior , whose range covers the Korean Peninsula, Primorye and Khabarovsk regions and, perhaps, China. We delineated several colour morphs of C. fluminea and C. japonica. The distinctness between these colour morphs can be attributed to both heritable and environmental factors. [ABSTRACT FROM AUTHOR]

With about 480 known species, Pilidiophora (phylum Nemertea) has been regarded as consisting of Hubrechtiiformes (~20 spp.) and Heteronemertea (~460 spp.). Most (~87%) of the latter belong to Lineidae (> 400 spp.), while the systematics of non-lineid heteronemerteans remains largely untouched. To explore the phylogeny of non-hubrechtiiformid, non-lineid pilidiophorans, we performed multilocus molecular phylogenetic analyses with five genes (18S, 28S, H3 , 16S and COI) from 41 newly sequenced specimens. Pilidiophora comprised Hubrechtellidae, Lineidae, Valenciniidae, the new family Eopilidiidae and a not formally named family-level heteronemertean taxon. Eopilidion misakiense gen. et sp. nov. is described from a specimen from Japan, but whether it belongs to Heteronemertea remains unclear. Apart from this new species, the following 11 new species of valenciniids are established, based on molecular sequences and external morphology (localities in parentheses): Baseodiscus giribeti sp. nov. (Panama), B. kakuii sp. nov. (Japan), B. komatsui sp. nov. (Japan), B. narusei sp. nov. (Japan), B. ohtsukai sp. nov. (Japan), B. paracelensis sp. nov. (Vietnam), B. profundus sp. nov. (Russian Far East), B. urgorrii sp. nov. (Spain), B. zebra sp. nov. (Japan), Oxypolella hiebertae sp. nov. (Vietnam) and Valencinura jambio sp. nov. (Japan). [ABSTRACT FROM AUTHOR]

Phylogenetic relationships of the two largest species groups in the genus Amiota [the Amiota alboguttata group (29 known and six new species) and the Amiota basdeni group (17 known and three new species)] were reconstructed using two mitochondrial gene sequences (COI and ND2). The paraphyly of the A. alboguttata group was identified based on molecular evidence. The monophyletic A. basdeni group is found to be nested in the A. alboguttata group, rendering the latter paraphyletic. Automatic barcode gap discovery and Bayesian phylogenetics and phylogeography methods were used to assess species limits of the A. alboguttata and A. basdeni groups. The results indicate that most analysed species could be delimited clearly, including nine new species (Amiota beama sp. nov. , Amiota cyclophylla sp. nov. , Amiota flormontana sp. nov. , Amiota obtusa sp. nov. , Amiota planiceps sp. nov. , Amiota scrobicula sp. nov. , Amiota jianjuni sp. nov. , Amiota tentacula sp. nov. and Amiota xinglaii sp. nov.), except for some closely related morphospecies. Furthermore, based on the highly biased distributions of these two groups, southwestern China is hypothesized to be a possible centre of origin and diversification for Amiota in East Asia. [ABSTRACT FROM AUTHOR]

Dibamid reptiles have a known current distribution on two continents (Asia and North America). Although this clade represents an early-diverging group in the Squamata and thus should have a long evolutionary history, no fossil record of these peculiar burrowing squamate reptiles has been documented so far. The fossil material described here comes from the early Oligocene of the Valley of Lakes in Central Mongolia. This material consists of jaws and is placed in the clade Dibamidae on the basis of its morphology, which is further confirmed by phylogenetic analyses. In spite of the fragmentary nature of this material, it thus forms the first, but putative, fossil evidence of this clade. If correctly interpreted, this material demonstrates the occurrence of Dibamidae in East Asia in the Palaeogene, indicating its distribution in higher latitudes than today. The preserved elements possess a unique combination of character states, and a new taxon name is therefore erected: Hoeckosaurus mongoliensis sp. nov. The dentary of Hoeckosaurus exhibits some characters of the two extant dibamid taxa. However, the open Meckel's groove, together with other characters, show that this group was morphologically much more diverse in the past. [ABSTRACT FROM AUTHOR]

Oligoneuriidae is a Pantropical family of Ephemeroptera, with 68 species described in 12 genera. Three subfamilies are recognized: Chromarcyinae, with a single species from East Asia; Colocrurinae, with two fossil species from Brazil; and Oligoneuriinae, with the remaining species distributed in the Neotropical, Nearctic, Afrotropical and Palaearctic regions. Phylogenetic and biogeographical analyses were performed for the family based on 2762 characters [73 morphological and 2689 molecular (COI , 16S, 18S and 28S)]. Four major groups were recovered in all analyses (parsimony, maximum likelihood and Bayesian inference), and they were assigned to tribal level, namely Oligoneuriini, Homoeoneuriini trib. nov. , Oligoneuriellini trib. nov. and Elassoneuriini trib. nov. In addition, Yawari and Madeconeuria were elevated to genus level. According to Statistical Dispersal-Vicariance (S-DIVA), Dispersal Extinction Cladogenesis (DEC) and divergence time estimation analyses, Oligoneuriidae originated ~150 Mya in the Gondwanan supercontinent, but was probably restricted to the currently delimited Neotropical region. The initial divergence of Oligoneuriidae involved a range expansion to Oriental and Afrotropical areas, sometime between 150 and 118 Mya. At ~118 Mya, the family started its diversification, reaching the Nearctic through dispersal from the Neotropical region and the Palaearctic and Madagascar from the Afrotropical region. [ABSTRACT FROM AUTHOR]