查看更多>>摘要：This research presents new material of ray-finned fishes recovered from Upper Cretaceous strata exposed in the city of Algarrobo, central Chile. The material includes specimens here referred to the genus Enchodus, which are the first local records of early Maastrichtian age. Three coeval, isolated teeth are here referred to the genus Pachyrhizodus, six distinctive, barracuda-like teeth are here referred to as indeterminate pachycormids. These finds represent the first record of Pachyrhizodus , the second record of a pachycormid in the Upper Cretaceous of southern South America. In addition, it is provided a critical review of the historic ray-finned fishes from the Upper Cretaceous Quiriquina Formation of central Chile and equivalent units within the Arauco Basin. The updated information suggests that latest Cretaceous actinopterygian diversity along the southeastern Pacific was much discrete than previously thought, and unusually scarce in terms of abundance. Locally, this scarcity was already present during the lower Maastrichtian and persisted throughout the end of the Cretaceous. (c) 2021 Elsevier Ltd. All rights reserved.
Lazo, Dario G.Bressan, Graciela S.Aguirre-Urreta, M. BeatrizAndrada, A. Mariel...
14页
查看更多>>摘要：A new species of Protaxius Beurlen, P. paucisaetosus sp. nov., is erected on the basis of 40 specimens from a single stratigraphic level within the Agrio Formation (lower Hauterivian) in the Neuque = n Basin. Specimen preservation varies from isolated chelae to complete exoskeletons, all invariably enclosed in concretions. Since the genus Protaxius had previously been interpreted as a junior subjective synonym of Etallonia Oppel, we have revised the type material of all the species assigned to Protaxius so as to assess this proposal; we here reject this and consider Protaxius to be distinct. Previous records of species of Protaxius are from the Upper Jurassic of Europe and Japan, making the present record not only the first from the Southern Hemisphere, but also the first report of the genus from the Cretaceous, extending its stratigraphical range. (c) 2021 Elsevier Ltd. All rights reserved.
查看更多>>摘要：The Caribbean islands are one of the most important hotspots of endemism and biodiversity globally, and the scenario of unique examples of biological radiations. Although our knowledge of the current and recently extinct diversity in the area is strong, the origin and evolution of most groups in the region remain obscure because of the absence of fossils from deep time periods. The existence of temporal islands on the Caribbean plate can be traced back to the late Mesozoic, but little evidence of the paleo-communities that once inhabited the archipelago and their relationship with the older lineages in the region has been discovered. Simultaneously, the relationship of the early Caribbean archipelago with the Late Cretaceous-early Paleogene biotic interchange between the Americas has remained unsolved. Here we describe the first evidence of a Late Cretaceous terrestrial community in the region based on several remains recovered at three upper Campanian-lower Maastrichtian localities in Central Cuba. The fossil assemblage includes four specimens referable to a midsize pterosaur on the base of morphological and paleohistological characters, as well as seeds and casts of leafy shoots of plants of the families Cupres-saceae and Lauraceae. Fossils fruits of a new taxon closely related to Chlorocardium are of particular interest because they correspond to the first direct evidence of the role played by the Caribbean seaway and islands in the First American Biotic Interchange. Published by Elsevier Ltd.
查看更多>>摘要：Mesozoic fossils of Psephenidae are sparse. Here we characterise, describe and figure a new genus and species of Psephenidae from the Albian/Cenomanian Burmese amber, Pseudomataeopsephus burmensis gen. et sp. nov, based on an adult male. Pseudomataeopsephus has an interesting combination of characters, including filiform antennae in male, pronotum with crenulate basal rim, scutellum and elytra with smooth basal rims, mesoventral process with emarginate apex, and abdomen with five ventrites. This unique character combination is unknown in any extant psephenid subfamilies, suggesting that Pseudomataeopsephus may represent an early-diverging lineage in Psephenidae. 0 2021 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A new well-preserved partial skeleton of the djadochtatheriid multituberculate Kryptobaatar is here described from the Campanian Bayan Mandahu Formation of the southern Gobi Basin in Inner Mongolia, China. We refer to it as Kryptobaatar sp. because it presents characters that are specific to Kryptobaatar dashzevegi and others specific to Kryptobaatar mandahuensis, as well as characters of its own. When those taxa are incorporated into a phylogenetic analysis of the Djadochtatherioidea, the Kryptobaatar species appear to be paraphyletic. This raises again questions about the high intraspecific variability in some multituberculates. Based on a comparison with the published specimens, we conclude that K. mandahuensis is a valid species, close to but distinct from K. dashzevegi. Our results also suggest that endemism alone in the Gobi Basin is not the cause of the high variability observed in the genus Kryptobaatar. But the impact of a possible difference in age or paleoenvironment between the different Kryptobaatar-bearing sites of the Gobi Desert is, for the moment, not possible to test in the current state of knowledge. (c) 2021 Elsevier Ltd. All rights reserved.
查看更多>>摘要：This work presents high-resolution palynological and micropalaeontological analyses of a cored succession across the upper Maastrichtian from a well in the More Basin (Norwegian continental shelf). Diverse assemblages of dinoflagellate cysts and foraminifera provide insights into the palaeobiogeography and palaeoenvironmental conditions during the late Maastrichtian in this region. An outer neritic setting is interpreted based on the general high abundance of planktonic foraminifera. A subdivision of the biostratigraphic record into three Ecozones has allowed for a detailed documentation of the phytoplankton communities during the late Maastrichtian until the K-Pg boundary. Ecozone A is characterised by a predominance of peridinoid cysts which together with abrupt fluctuations in planktonic foraminifera suggests high nutrient availability and, possibly, high terrestrial input potentially associated with regional turbiditic currents. Also, the occurrence of taxa characteristic of boreal affinity suggests colder waters for this Ecozone. Ecozone B is characterised by consecutive influxes of areoligeracean species such as Palynodinium grallator, Areoligera senonensis and Circulodinium distinctum in the dinoflagellate cyst assemblages. The increase abundances of planktonic foraminifera across this interval suggests an increase in palaeowater depth into a more outer shelf to upper slope. Immediately before the K-Pg boundary (Ecozone C), an increase in abundance of low latitude dinoflagellate species and the planktonic foraminifera Pseudotextularia elegans may represent the local signal of the global latest Maastrichtian Warming Event. Two new dinoflagellate cyst species restricted to the late Maastrichtian, Glaphyrocysta turgida sp. nov. and Heterosphaeridium silybum sp. nov. are also formally described. (c) 2021 Elsevier Ltd. All rights reserved.
查看更多>>摘要：The iron maiden ant, which was first described as tZigrasimecia Barden & Grimaldi, 2013, received its nickname for bearing a unique mandible and ferocious mouthparts covered by spiky, columnar-shaped denticles. Here, we describe a new species based on an alate female preserved in 99-Ma Kachin amber -tZigrasimecia goldingot sp. nov. -which displays several diagnostic features shared with the known species of this genus. Such features include the peg-like mandibular setae, setae of the labrum, clypeal denticles, and an omega-shaped head capsule. Our findings suggest a high diversity among tZigrasimeciinae and support the grouping of this subfamily. Our work adds to the biodiversity of tZigrasimecia and tZigrasimeciinae, and explores the morphological and functional aspects, as well as the early appearance of the unique mouthparts in this ancient ant group. (c) 2021 Elsevier Ltd. All rights reserved.
Rombola, Cosme F.Greppi, Carlos D.Pujana, Roberto R.Garcia Massini, Juan L....
12页
查看更多>>摘要：Two silicified fossil woods from outcrops of the Cerro Fortaleza Formation (Campanian, Upper Cretaceous) in Los Hornos Hill, Santa Cruz Province, Argentina are described. Based on their anatomical characteristics, both specimens were assigned to a new species of the fossil genus Brachyoxylon Hollick and Jeffrey, B. patagonicum sp. nov. They are characterized by having distinct growth ring boundaries, absence of axial parenchyma, uniseriate rays, mixed and uniseriate intertracheary radial pitting, and araucarioid cross-fields with 1-8 circular half-bordered pits per cross-field. In turn, one specimen has three rows of axial traumatic resin canals parallel to the growth rings were identified close to the middle of the growth rings or close to the latewood. Approximately 45% of Brachyoxylon species present traumatic resin canals, which suggests that they are a common feature of this fossil genus. Alternatively, the specimen with the canals shows biological remains (hyphae) and wood fungal degradation patterns, which may be thought as some of those of possible organisms contributing to the formation of the resin canals. This record provides fresh evidence attesting to the abundance and widespread distribution of Cheirolepidiaceae in the Cretaceous of Patagonia. (c) 2021 Elsevier Ltd. All rights reserved.
Carmo, Daniel D. D.Lamas, Carlos J. E.Ribeiro, Guilherme C.
6页
查看更多>>摘要：A new extinct genus of the Diptera family Therevidae is described from the Lower Cretaceous Crato Formation of Northeastern Brazil. Cretothereva antiqua gen. et sp. nov. is the oldest known fossil of the family Therevidae and the entire therevoid clade. The new taxon cannot be classified in any existing subfamily, and probably correspond to a stem lineage of the Therevidae. The new finding presented herein brings light on the minimum age of therevoids, and falsifies current biogeographical hypotheses standing for a North American origin of the family Therevidae. (c) 2021 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A new species of conifer wood, Brachyoxylon lalongense sp. nov., was discovered from the Lower Cretaceous Duoni Formation of Bangoin County in the northern part of the Lhasa Block, Southwest China. The anatomical structure of the secondary xylem is characterized by the absence of growth rings, mixed type of radial tracheary pitting, araucarioid cross -field pits, uniseriate xylem rays, and the absence of resin canals. The absence of growth rings in the secondary wood indicates that this conifer was evergreen and the area was dominated by a hot climate during the Early Cretaceous. This conclusion is coincident with the coeval palaeobotanical and palynological evidences discovered in Tibet. (c) 2021 Elsevier Ltd. All rights reserved.
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