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The real Devario browni from the Irrawaddy River basin, and the new Devario ahlanderi from the Salween River basin in Myanmar (Teleostei: Cyprinidae: Danioninae)
No full textSpecimens of Devario from a tributary to the Salween River in Myanmar initially identified as Devario browni but witha different colour pattern, were subjected to a comparative morphological analysis with syntypes and other specimens of D. browni from near its putative type locality. The Salween sample was recognised as representing a distinct species, here named Devario ahlanderi. No significant morphometric differences were found between D. ahlanderi and D. browni.The type series of Devario ahlanderi differed from D. browni and most other species of Devario in the presence of 14 vs 12 circumpeduncular scale rows. Devario ahlanderi, D. browni, and D. fangae shared subadult colour pattern. Adult D. ahlanderi differed from adult D. browni in the trunk colour pattern, consisting of rows of dark blotches or short vertical bars. In D. browni, the flank colour pattern consisted of horizontal dark stripes, the middle of which (the P stripe) frequently diverged anteriorly, enclosing a small light blotch. Specimens previously reported as D. browni from the upper Salween River basin in Yunnan differed slightly in colour pattern, and may represent a distinct species. Devario ahlanderi shared spotted colour pattern with that of one ontogenetic state in D. kysonensis, except that a row of spots marking the P-1 stripe in D. kysonensis was absent in D. ahlanderi. The minimum genetic distance between D. ahlanderi and congeneric species varied from 2.1 to 5% in the mt-coI gene
Miocene Nautilus (Mollusca, Cephalopoda) from Taiwan, and a review of the Indo‐Pacific fossil record of Nautilus
No full textThe fossil record of the cephalopod genus Nautilus has been obscured because a few influential taxonomists during the 20th Century decided that fossils similar to Nautilus were instead other genera. We now recognize fossils once classified as species of other genera as species of Nautilus. This includes fossils from Miocene rocks of Taiwan that were previously described as Kummelonautilus taiwanum but herein recognized instead as being the northernmost Neogene record of Nautilus in the Indo-Pacific region. The name is corrected to Nautilus taiwanus, and now known to occur in two formations in central Taiwan, the early Miocene Shihmentsun and early to middle Miocene Houdongkeng formations. Miocene fossils from Indonesia that were placed in other genera are now considered to represent Nautilus as they were originally assigned, in addition to several Miocene species from Australia, which provide the southernmost Neogene fossil record for the genus. Some of these Indo-Pacific fossils may represent the same species, but more specimens are needed to determine the amount of variability within these Neogene taxa.Financial support was provided by the Swedish Research Council (Vetenskapsrådet) through grant 2016-03920 to Steffen Kiel. Cheng-Hsiu Tsai was financially supported by the Taiwan Ministry of Science and Technology (MOST 108-2621-B-002-006-MY3) and the public donations to National Taiwan University (NTU FD107028 for the Lab of Evolution and Diversity of Fossil Vertebrates).</p
Lipid Biomarker Patterns Reflect Nutritional Strategies of Seep-Dwelling Bivalves From the South China Sea
No full textInvertebrates living at methane seeps such as mussels and clams gain nutrition through symbiosis with chemosynthetic, chiefly methanotrophic and thiotrophic bacteria. Lipid biomarkers, including their compound-specific carbon stable isotope compositions, extracted from the host tissues are predestined for deciphering the various sources of diets and the associations among varying environments, endosymbionts, and hosts. Here, we investigated lipid inventories of soft tissues of two bathymodiolin mussel species hosting aerobic methanotrophic bacteria (Gigantidas platifrons from Site F and Gigantidas haimaensis from Haima seeps), one bathymodiolin mussel with thiotrophic bacteria (Bathymodiolus aduloides from Haima seeps), and one vesicomyid clam (Archivesica marissinica from Haima seeps) from the South China Sea. The gills of mussels hosting methanotrophic symbionts were found to contain high amounts of lipids of aerobic methanotrophic bacteria, such as the 4,4-dimethyl lanosterol, and other 4-methyl sterols, and the type I methanotroph-specific monounsaturated fatty acids (MUFAs) C16:1ω9 and C16:1ω8. Production of methyl-sterols is favored over fatty acids at low oxygen concentrations, as demonstrated in culture experiments with Methylococcus capsulatus. Since lesser fatty acids and abundant sterols are found in G. haimaensis compared to G. platifrons, G. haimaensis apparently lived at very low oxygen levels. Extremely high levels of MUFAs C16:1ω7 and C18:1ω7 were found in gill tissue of both B. aduloides and the vesicomyid clam A. marissinica. Given the absence of ω8 fatty acids, both B. aduloides and the vesicomyid clam contain thiotrophic bacteria only. The occurrence of 13C-enriched 24-methylenecholesterol in B. aduloides indicates that the animal complemented its diet by filter-feeding (ca. 3% of the total sterol inventory) on photosynthetically derived carbon, whereas the majority of sterols are pointing to a diet relying on endosymbionts. Different types of 4-methyl sterols were observed between the thiotroph-containing mussel and methanotroph-containing mussels, suggesting different biosynthetic steps are present from lanosterol to cholesterol between animal hosts and aerobic methanotrophs. Among the four bivalve species, specific lipid biomarker patterns diagnostic for either the symbionts or the hosts yielded similar δ13C values in each species, indicating that the host obtained its nutrition either directly from the symbionts or derived at least most of its carbon in this way. The information derived from lipid biomarkers of bivalves and their corresponding symbionts in modern environments is vital to interpret data from the rock record, where most other methods to study microbial community composition are not applicable.This research was supported by NSF of China (Grant Number 91958105) and the Shandong Special Fund of Pilot National Laboratory for Marine Science and Technology (Qingdao; Grant Number 2021QNLM020002).</p
Arctic ice and the ecological rise of the dinosaurs
No full textAbundant lake ice-rafted debris in Late Triassic and earliest Jurassic strata of the Junggar Basin of northwestern China (paleolatitude ~71°N) indicates that freezing winter temperatures typified the forested Arctic, despite apersistence of extremely high levels of atmospheric Pco2 (partial pressure of CO2). Phylogenetic bracket analysis shows that non-avian dinosaurs were primitively insulated, enabling them to access rich deciduous and evergreen Arctic vegetation, even under freezing winter conditions. Transient but intense volcanic winters associated withmassive eruptions and lowered light levels led to the end-Triassic mass extinction (201.6 Ma) on land, decimating all medium- to large-sized nondinosaurian, noninsulated continental reptiles. In contrast, insulated dinosaurs were already well adapted to cold temperatures, and not only survived but also underwent a rapid adaptive radiation and ecological expansion in the Jurassic, taking over regions formerly dominated by large noninsulated reptiles.This is a contribution to UNESCO-IUGS IGCP project 632 and the CycloAstro Project funded by the Heising-Simons Foundation. This work wassupported by the National Natural Science Foundation of China (41730317), the Chinese Academy of Geological Sciences (DD20190009), the Special Basic Program of Ministry of Science and Technology of China (2015FY310100), the Bureau of Geological Survey of China, and the National Committee of Stratigraphy of China (DD20160120-04). The Lamont Climate Center is acknowledged for support to P.O., C.C., and S.K. The LDEO repository is funded by NSF OCE-1259124 and the OSU NSF OCE-1558679. Additional funding was provided by the Heising-Simons Foundation (award no. 2021-2801), the Swedish Research Council (VR grant2019), and the Knut and Alice Wallenberg (KAW) Foundation</p
On the identity of three little-known Microterys Thomson species (Hymenoptera: Encyrtidae)
No full textIllustrated redescriptions are given for three species of encyrtid wasps first described in the early 1800s: Microterys cedrenus (Walker), M. cyanocephalus (Dalman) and M. interpunctus (Dalman), and four new synonyms are proposed: M. aldreyi Japoshvili (of M. cedrenus), M. dichrous (Mercet) (of M. cedrenus), M. steinbergi Sugonjaev (of M. cyanocephalus), and M. duplicatus (Nees) (of M. interpunctus)
Correlation of Cretaceous deposits along the Dniester river (Ukraine) by palynological and lithological methods
No full textA geochronological review of magmatism along the external margin of Columbia and in the Grenville-age orogens forming the core of Rodinia
No full textA total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari (southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10 000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set. Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia.
Life in the woods: Taphonomic evolution of a diverse saproxylic community within fossil woods from Upper Cretaceous submarine mass flow deposits (Mzamba Formation, southeast Africa)
No full textOrganisms that colonize wood are subject to a taphonomic tragedy—the richer and more diverse they become, the greater the deterioration of the host wood and the less likely such communities are to be fossilized. Moreover, palaeobotanical studies of fossil wood usually focus on the plant tissue, neglecting the evidence of parasitic, saproxylic, and other contained organisms. Such a case involved a relatively well-known fossil wood assemblage from the Santonian (Late Cretaceous, ca 84 Ma) of southeast Africa. In a set of 150 thin sections of silicified wood stored in the Senckenburg Museum for more than half a century, we discovered evidence of a diverse biotic community comprising bacteria, fungi, nematodes, several types of arthropods, and marine bivalves. These body fossils and traces, together with growth-ring features, fossil log size and shape, and the distribution of glauconite, facilitated interpretation of the multi-stage evolution of a wood-hosted biocoenosis of unprecedented diversity. This record is unique for the Mesozoic and is of importance for understanding the taphonomic pathways to preservation and the evolution and diversification of saproxylic and other wood-hosted communities in terrestrial and marine settings
Triassic coleoid beaks and other structures from the Calcareous Alps revisited
No full textWe performed comprehensive study of seven Carnian, Late Triassic specimens of a coleoid cephalopod Phragmoteuthis bisinuata, on which Suess based his hypothesis on “beaks of P. bisinuata”. Using SEM/EDS, we found that “beaks of P. bisinuata” consist of a micro-granular carbonized matrix containing ~4–30 μm diameter and ~50–200 μm visible length, dense calcified bone-like micro-structures. This strongly suggests that these objects are vertebrate bone-inducing cartilages in which the matrix was post-mortem reworked by carbon-accumulating bacteria and substituted by nano-particles of carbon accumulated in micro-granules. Hence, the presumed “beaks of P. bisinuata” are cartilaginous remains of a prey, presumably juvenile fish. This data dismissed the entire hypothesis of Seuss. A small spatula-shape plate with a rachis-like process in an association with 10 or so imprints around (arm crown), found in front of a proostracum of P. bisinuata evidences an unknown Late Triassic juvenile teuthid which possessed a gladius resembling that of the early Permian Glochinomorpha stifeli. It inhabited the open sea area of the northwestern Tethys Ocean, and was, along with juvenile fishes, in the diet of P. bisinuata. The first identified Anisian (Middle Triassic) coleoid beak is represented by an isolated specimen from the Gardena Valley, NE Italy. It has a typical composition and morphology of coleoid upper beak: chitinous, wide-oval lateral walls, short wings, and pointed hook-like rostrum. This suggests similar upper beak structure in the Carnian P. bisinuata in which the lower beaks were apparently similar to that of the co-occurring Lunzoteuthis schindelbergensis and had a widely open outer lamella with posteriorly elongated paired wings joined into a pointed rostrum in the anterior portion.This study was carried outthanks to financial support of the Austrian and Swedish Academies of Sciences, Department of Geology and Paleontology of the Museum of Natural History in Vienna and the Society “Friends of the Museum of Natural History, Vienna”, Department of Palaeobiology of the Swedish Museum of Natural History, and Museo de Ghereina, Italy</p