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1.
Abstract

The current study reports the effects of heavy metals issued from the emissions of phosphate and their bioaccumulation in the soils, leaf litter, and the terrestrial isopod Porcellionides pruinosus in the vicinity of Gabes-Ghannouch industrial complex. Cd, Pb, Zn, and Cu concentrations were measured in soils, leaf litter, and P. pruinosus individuals, collected from four stations located at different distances from the factory. Results showed that heavy metal concentrations in soils varied from one site to another and did not reflect those measured in individuals. In contrast, a positive correlation was found between the isopods’ body length and the distance from the pollution source, revealing the isopod sensitivity to the soil metal concentrations. The bioaccumulation factor was calculated using soil and leaf litter as a solid support with the aim of ordering the metal accumulation in P. pruinosus for each site. Overall, P. pruinosus could be defined as a macroconcentrator of Cd, Zn, and Cu (BAF?>?2) and as a deconcentrator of Pb (BAF?<?1).  相似文献   

2.
A fossil flora from the Late Paleocene-Early Eocene Thyra Ø Formation of eastern North Greenland (paleolatitude 77° N) has yielded monocotyledon leaf impressions with characters seen only in the closely related modem species in the families of Heliconiaceae, Musaceae, and Strelitziaceae. The combination of large costae widths and parallel, nonanastomosing, lateral veins that depart at right angles from the costae in the fossil material are features present only in leaves of extant species from these families. Three basic venation patterns also are recognized in the modem species of these families, but except for the genera Strelitzia and Phenakospermum, none of these patterns are present exclusively in any one family. Musopsis n. gen. is created for the fossil material from Greenland, but it is considered a form genus due to the lack of gross morphological features that can be used for separating leaves of the modem genera in Heliconiaceae, Musaceae, and Strelitiziaceae. It is the first known Arctic occurrence of fossil leaf material resembling this modem group of taxa.  相似文献   

3.
Peter H. Gibson 《Ichnos》2017,24(2):83-90
This study used measurements and observations on the burrows of extant species of Dodecaceria fimbriata and D. concharum to identify their possible fossil burrows. The extant burrows were from marine littoral shale and the calcareous alga Lithothamnion. From published records unequivocal fossil burrows were not found for these two species. Trace fossils of D. fimbriata appear to have been present in the Miocene and Dodecaceria cretacea (probably not Dodecaceria) in the Cretaceous. The conclusion is that D. fimbriata and D. concharum separated from a common ancestor in the late Cretaceous.  相似文献   

4.
A fossil of the aerophytic green algal genus Phycopeltis (Trentepohliaes, Ulvophyceae) dated to 35 Ma, is reported from the Pikopiko Fossil Forest, Southland, New Zealand. Previous reports of fossilized Phycopeltis have been subsequently synonymized with fungi by other authors; however, our specimen is not vulnerable to their criticisms. Inflated cells present in two approximately concentric rings are interpreted as gametangia, with irregular structures resembling the gametangial pores of modern material; sporophytic material is absent. The fossil resembles the modern disc‐forming species P. novae‐zelandiae, P. expansa, and P. arundinacea. The limited material available prevents the assignation of a specific epithet, but the habit and dimensions of the fossil clearly fall within those of modern representatives of the genus. Its single cell thickness throughout, absence of distinct melanization, and larger size demonstrate that it is not a fungal shield. The specimen constitutes arguably the most convincing fossil belonging to Trentepohliales, and the first unambiguously for the genus Phycopeltis. It is consistent in age with other known fossils of the order that, when combined with molecular evidence, suggests a terrestrial radiation far more recent than that of land plants.  相似文献   

5.
Three new species of Mya Linné are described from Greenland. Mya eideri sp. nov. is figured and compared with boreal and fossil species with which it has been confused, and the known distribution of the species is indicated. The validity in Recent faunas of the fossil species M. pseudoarenaria and M. uddevallensis is discussed; two new Recent species, M. neoovata sp. nov. and M. neouddevallensis sp. nov., from Ikka Fjord, southwest Greenland, and Scoresbysund, East Greenland, respectively, are described for Recent material of the comparable two fossil taxa. Accepted: 2 May 1999  相似文献   

6.
A humerus and a coracoid from the Early Eocene Wasatch Formation in the Washakie Basin of south‐western Wyoming are the oldest materials (by ~2 million years) of the pelecaniform Limnofregata (Aves) and represent a new large species, Limnofregata hutchisoni sp. nov. This fossil is the oldest known member of the frigatebird lineage. Other than its large size relative to Limnofregata azygosternon and Lhasegawai, the new material is very similar morphologically to other known Limnofregata specimens. The size of this new species is comparable to the largest living species (e.g. Fregata minor and Fregata magnifiscens) and much larger than the two described species of Limnofregata. This fossil indicates that the hard minimum date previously advocated for molecular calibration of the split between Fregatidae and Suloidea is an underestimate by approximately two million years. The presence of early pelecaniform bird lineages (represented by Limnofregata and Masillastega) in limnic ecosystems prior to their known occurrences in marine deposits/habitats appears to indicate that some clades of pelecaniform birds may have undergone an evolutionary transition from freshwater to marine habitats in a pattern reminiscent of what has been suggested during the evolution of pinnipeds or that their palaeoecology included broader niches ranging across a variety of aquatic habitats. That transition in habitat occupation and the origin of many of the characteristic biological aspects present in the crown frigatebird clade likely occurred during a significant temporal gap (> 45 million years) in the fossil record of the frigatebird lineage after these earliest occurrences in the Early Eocene and before the oldest records of the extant Fregata species in the Pleistocene.  相似文献   

7.
A well-preserved Macaranga leaf fossil from the middle Miocene Fotan Group of Zhangpu County, Fujian, South-eastern China is examined and described as a new species, Macaranga zhangpuensis Z.X. Wang et B.N. Sun sp. nov. The present fossil species represents the highest latitudinal distribution of a reliable Macaranga fossil in the world, and we present the first Macaranga fossil described with detailed cuticular characteristics from China. Based on the global palaeogeographic distribution of Macaranga, we infer that the genus probably originated during the Oligocene in Africa and spread from Africa to India and then to South Fujian, China, further into the Mariana Islands and finally into the Philippine Islands and Malaysia, leading to its present distribution. In addition, the new leaf material described herein is the first Macaranga fossil record with three leaf tips globally. This finding demonstrates that Macaranga with three leaf tips already existed during the Miocene in Fujian, South China, and it provides new information for understanding climatic changes between the Miocene and the present -day.  相似文献   

8.
The diatom genus Toxarium Bailey has been treated as a pennate because of its elongate shape and benthic lifestyle (it grows attached to solid substrata in the marine sublittoral). Yet its valve face lacks all structures that would ally it with the pennates, such as apical labiate processes, a midrib (sternum) subtending secondary ribs and rows of pores extending perpendicularly out from the midrib, or a raphe system. Instead, pores are scattered irregularly over the valve face and only form two distinct rows along the perimeter of the valve face. In our nuclear small subunit rDNA phylogenies, Toxarium groups with bi‐ and multipolar centrics, as sister to Lampriscus A. Schmidt. Thus, the genus acquired a pennate‐like shape and lifestyle independently from that of the true pennates. The two species known, T. hennedyanum Grunow and T. undulatum Bailey, differ only in a single feature: the valve perimeter of the former shows only a central expansion, whereas that of the latter possesses in addition a regular undulation. Yet both forms were observed in our monoclonal cultures, indicating that the two taxa represent extremes in a plasticity range. Toxarium resembles another elongate and supposedly araphid diatom, Ardissonea De Notaris, in being motile. Cells can move at speeds of up to 4 μm·s ? 1 1 Received 7 June 2002. Accepted 4 October 2002. through secretion of mucilage from the cell poles or they remain stationary for longer periods, when they form short polysaccharide stalks. Division during longer periods of quiescence leads to the formation of small colonies of linked or radiating cells.  相似文献   

9.
Abstract

Gobies (family Gobiidae) were in the past and now important components of marine ecosystems as an essential part of the food chain. However, the early fossil record of this group is relatively meager, with only scarce skeletal remains. The oldest known representative of the genus Gobius has been recently described from the Early Miocene of Czech Republic as Gobius jarosi P?ikryl & Reichenbacher, 2018. Here we present a detailed study of a well-preserved goby skeleton of the same age from the Harta locality (Poland). This specimen is assumed as belonging to Gobius jarosi based on its almost complete morphological and meristic identity with the type material from the Vá?any nad Litavou locality. Some aspects of the paleogeography and paleoecology of the Early Miocene fish assemblage from Harta with special reference to the Carpathian Basin are also discussed in this paper.  相似文献   

10.
It is demonstrated in this paper that before we can hope to formulate phylogenetic relationships between and amongst fossil hominoid material it is first necessary to sex the material accurately. In order to determine whether the morphological and morphometrical variability seen in fossil specimens is due to sexual or inter species dimorphism, it is necessary to calibrate fossil specimens against extant hominoid species' morphologies. Only after fossil specimens have been sexed is it possible to differentiate between morphologies that are related to sex and those that are species specific. This will help reduce fossil misallocation. A morphometric analysis of extant and fossilProconsul hominoid material is presented. Each fossil specimen has been sexed according to symplesiomorphic sex morphologies as defined in this paper. After the fossil specimens have been sexed they are analyzed using multivariate statistics. The identification of differing sex patterns within the specimens examined here suggests that a new species ofProconsul may have to be considered.  相似文献   

11.

The ichnogenus Tonganoxichnus, produced by one or more monuran insect taxa, is now recorded from the Middle Pennsylvanian Mansfield Formation of Indiana. Tonganoxichnus is a resting trace that has three important implications. First, it represents a recurrent behavioral pattern in Upper Carboniferous to Lower Permian marginal marine environments of North America. Second, it provides finely resolved anatomical information for axial and appendicular body structures and behaviors that are difficult to determine from body‐fossil material alone. Third, integrated sedimentologic and ichnologic observations indicate that the Tonganoxichnus assemblage, inclusive of other ichnotaxa, is common in tidal rhythmites that were developed under freshwater conditions, probably in the innermost part of estuarine systems, close to or at the fluvioestuarine transition.  相似文献   

12.
13.
Pseudotettigonia leona sp.n. is described from a single left forewing collected from the Middle Eocene Kishenehn Formation in northwestern Montana, U.S.A. P. leona is the second of only two fossil macropterous Tettigoniidae that preserve an intact stridulatory apparatus. The subfamily Pseudotettigoniinae is reexamined. The specific epithet bricei is assigned to the late Miocene fossil tettigoniid Tettigonia bricei sp.n. , originally described as the extant Tettigonia viridissima. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:E69E83CE‐9046‐4BBD‐AA11‐E0AD0C382700 .  相似文献   

14.
15.
Extant baleen whales (Cetacea, Mysticeti) are a disparate and species‐rich group, but little is known about their fossil record in the northernmost Atlantic Ocean, a region that supports considerable extant cetacean diversity. Iceland's geographical setting, dividing North Atlantic and Arctic waters, renders it ideally situated to shed light on cetacean evolution in this region. However, as a volcanic island, Iceland exhibits very little marine sedimentary exposure, and fossil whales from Iceland older than the late Pleistocene are virtually unknown. Here, we present the first fossil whale found in situ from the Pliocene Tjörnes Formation (c. 4.5 Ma), Iceland's only substantial marine sedimentary outcrop. The specimen is diagnosed as a partial skull from a large right whale (Mysticeti, Balaenidae). This discovery highlights the Tjörnes Formation as a potentially productive fossil vertebrate locality. Additionally, this find indicates that right whales (Eubalaena) and bowhead whales (Balaena) were sympatric, with broadly overlapping latitudinal ranges in the Pliocene, in contrast to the modern latitudinal separation of their living counterparts.  相似文献   

16.
The end‐Devonian mass extinction has been framed as a turning point in vertebrate evolution, enabling the radiation of tetrapods, chondrichthyans and actinopterygians. Until very recently ‘Romer's Gap’ rendered the Early Carboniferous a black box standing between the Devonian and the later Carboniferous, but now new Tournaisian localities are filling this interval. Recent work has recovered unexpected tetrapod and lungfish diversity. However, the composition of Tournaisian faunas remains poorly understood. Here we report on a Tournaisian vertebrate fauna from a well‐characterized, narrow stratigraphic interval from the Ballagan Formation exposed at Burnmouth, Scotland. Microfossils suggest brackish conditions and the sedimentology indicates a low‐energy debris flow on a vegetated floodplain. A range of vertebrate bone sizes are preserved. Rhizodonts are represented by the most material, which can be assigned to two taxa. Lungfish are represented by several species, almost all of which are currently endemic to the Ballagan Formation. There are two named tetrapods, Aytonerpeton and Diploradus, with at least two others also represented. Gyracanths, holocephalans, and actinopterygian fishes are represented by rarer fossils. This material compares well with vertebrate fossils from other Ballagan deposits. Faunal similarity analysis using an updated dataset of Devonian–Carboniferous (Givetian–Serpukhovian) sites corroborates a persistent Devonian/Carboniferous split. Separation of the data into marine and non‐marine partitions indicates more Devonian–Carboniferous faunal continuity in non‐marine settings compared to marine settings. These results agree with the latest fossil discoveries and suggest that the Devonian–Carboniferous transition proceeded differently in different environments and among different taxonomic groups.  相似文献   

17.
Escontria chiotilla, Polaskia chichipe, and Stenocereus pruinosus are species of Mexican columnar cacti that are economically important because of their edible fruits. These species are managed by gathering fruits from the wild, silvicultural management in agroforestry systems, and cultivation in home gardens. Previous studies reported that artificial selection favored individuals that produced larger fruits, which indirectly led to the production of larger seeds and seedlings, with possible effects on survival. We hypothesized that seedlings from managed populations would be larger but more susceptible to xeric conditions than those from wild populations. We evaluated the effects of artificial and natural selection on seedling survival of the three species in wild and managed populations, which were managed with low and high intensity, respectively. We tested seedling performance in gradients of shade (0, 40, and 80%) and humidity (low and high). A GLM of seedling survival showed significant differences among species, shade, and humidity treatments, with each species having environmental requirements associated with their particular adaptations. High humidity decreased seedling survival of all species, and high solar radiation decreased survival of S. pruinosus and P. chichipe. The effect of management type was significant only in S. pruinosus. Significant differences in the initial growth of seedlings among species were detected with ANOVA. In optimal conditions, the hypocotyl and the cotyledons decreased in size and the epicotyl grew, whereas under stress, these structures remained unchanged. The optimum conditions of shade and humidity varied among species and management types. The seedlings of S. pruinosus were the largest and the most susceptible, but in all species, seedlings from managed populations were more susceptible to environmental conditions. Thus, artificial selection influenced the susceptibility of these cacti to xeric environments.  相似文献   

18.
Summary The heliozoeans Pinaciophora denticulata Thomsen, Acanthocystis perpusilla Petersen et Hansen, Acanthocystis turfacea Carter and Acanthocystis sp., collected from a marine location in Ellis Fjord, Antarctica and grown in saline culture, are pictured by scanning and transmission electron microscopy. P. denticulata has been reported from cold marine localities elsewhere in the world, but marine reports of Acanthocystis are rare, and both A. perpusilla and A. turfacea have been reported previously only from fresh waters.  相似文献   

19.
A taxonomic and biostratigraphical re‐assessment of Subterraniphyllum Elliott (Corallinales, Rhodophyta) is presented. Results from studies of the type collection and of newly collected material from north‐eastern Italy and northern Slovenia have shown that this taxon is not a geniculate coralline red alga as originally suggested by Elliott and most subsequent authors. Vegetatively, Subterraniphyllum most closely resembles certain living members of the Corallinales; however, the phenetic and phylogenetic relationships of Subterraniphyllum to other Corallinales cannot be determined with greater certainty. The exclusion of Subterraniphyllum from any group of Corallinaceae with genicula is based on unequivocal evidence that branch formation does not involve the occurrence of genicula. Subterraniphyllum seems to be restricted to the Oligocene. Reports of occurrences in Upper Eocene and Lower Miocene sediments cannot be substantiated. Subterraniphyllum, however, cannot be considered a useful stratigraphical marker until further data on its occurrence in well‐dated carbonate sequences are acquired. This study illustrates the problems associated with placing fossil coralline algal specimens into geniculate genera without the preservation of relevant morphological characters. This is especially true in the absence of the careful assessment of fossil material with respect to current taxonomic concepts of geniculate coralline genera, all of which are based on studies of living species. According to the current concepts for geniculate coralline genera, the placing of fossil specimens into geniculate genera without appropriate evidence must be avoided by grouping all potentially geniculate fragments under the informal group ‘Geniculate sensu lato’. Furthermore, for all those many fossil specimens where unequivocal evidence is not present, it is possible to utilize ‘form genera’ based on characters that are normally preserved. This leads to creating a consistent, workable system of applying names to most fossil corallines so that they can be reliably used in relation to stratigraphical and palaeoecological studies.  相似文献   

20.
Osedax worms subsist entirely on vertebrate skeletons on the seafloor, using root-like tissues to bore into and degrade the bones. Paleontologists have only recently begun to appreciate the possible destructive effect that these worms may have had on the marine vertebrate fossil record and little is known of their evolutionary history. Using microcomputed tomography, we document Osedax-like borings in a fossil whale bone from the Pliocene of Italy and present new data on the borings of extant Osedax worms. The fossil borings are distinguished from those of other known borers and identified as traces of Osedax activity based on diagnostic features. Our results suggest that it is necessary to isolate individual borings for the confident identification of Osedax traces. This is only the second paleogeographic occurrence of Osedax in the fossil record and indicates that by the Pliocene these worms had colonised a large portion of the world's oceans. This is the first evidence for Osedax in the Mediterranean, past or present, and suggests that more species await discovery in this region.  相似文献   

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