首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Abstract:  Abundant and diverse bioerosion trace fossils in the Lower Devonian of the Rade de Brest, France, were produced by boring ctenostomate bryozoans, polychaete annelids and algae. Two unidentifiable traces of encrusting sclerobionts are also considered. Two new taxa are described: Pinaceocladichnus cristatus ichnosp. nov. and Ichnogutta erectus ichnogen. et ichnosp. nov. Both are attributed to the work of boring bryozoans. Sedimentary condensation during intervals of sea-level rise seems to have had an important influence in promoting infestation by organisms, the activities of which are now preserved as trace fossils. A zonation of bioerosion trace fossils within the offshore zone, in the Lower Devonian of the Armorican Massif, is also suggested.  相似文献   

2.
Three new trace fossils are described from Miocene paleosols of southern Argentina. Celliforma pinturensis, n. ichnosp. and Celliforma rosellii, n. ichnosp. are interpreted as cells of digging bees, possibly Anthophoridae, and Coprinisphaerafrenguellii, n. ichnosp. are brood balls of dung‐beetles. Both burrowing bees and dung‐beetles are common nesters in relatively open areas, confirming previous reconstructions of the paleoenvironment of the Pinturas Formation. A brief review of scarabeid and bee fossil nests from South America is presented, and we propose that constructed nests have a higher preservation potential than excavated nests. This fact explains their more common occurrences as trace fossils in paleosols. A new ethological category, calichnia, is proposed for hymenopterous and coleopterous traces, in which adult individuals make nests exclusively for larvae.  相似文献   

3.
The low Lower Cambrian rocks from the Sierra de Córdoba contain one of the best successions in Europe, which consists of well exposed mixed facies with abundant fossil assemblages showing long stratigraphical ranges throughout the Pedroche Formation. These assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobes, trace fossils and stromatolites. Trace fossils are still poorly known, and thus they are the main objective of this work. Ichnological data are obtained from the Arroyo de Pedroche 1, Arroyo de Pedroche 2 and Puente de Hierro sections. Trace fossils include the ichnogenera Bergaueria, aff. Bilinichnus, Cochlichnus, aff. Cosmorhaphe?, Cylindrichnus, Dactyloidites, Dimorphichnus, Diplichnites, Monocraterion, Palaeophycus, aff. Phycodes, Planolites, Psammichnites, Rusophycus, Skolithos, Torrowangea and Treptichnus, as well as faecal pellets, meniscate trace fossils and others. They are abundant in shales and sandstones, and indicate important changes in the benthic conditions with respect to the underlying Torreárboles Formation. Changes in fossil assemblages within Member I of the Pedroche Formation indicate palaeoecological disruptions, which led to the disappearance of numerous archaeocyath species and the decrease of stromatolite biodiversity. This was followed by dominance of trilobite and brachiopod assemblages, accompanied by trace fossils of the Psammichnites ichnosp. A ichnoassociation. This biotic turnover (Pedroche event) occurred at the lower part of the archaeocyath Zone III, within the Bigotina bivallata biozone. The diagnoses of the ichnospecies Cochlichnus anguineus and Dactyloidites cabanasi are emended.  相似文献   

4.
A new, diverse and complex Early Triassic assemblage was recently discovered west of the town of Paris, Idaho (Bear Lake County), USA. This assemblage has been coined the Paris Biota. Dated earliest Spathian (i.e., early late Olenekian), the Paris Biota provides further evidence that the biotic recovery from the end-Permian mass extinction was well underway ca. 1.3 million years after the event. This assemblage includes mainly invertebrates, but also vertebrate remains such as ichthyoliths (isolated skeletal remains of fishes). Here we describe first fossils of Chondrichthyes (cartilaginous fishes) from the Paris Biota. The material is composed of isolated teeth (mostly grinding teeth) preserved on two slabs and representing two distinct taxa. Due to incomplete preservation and morphological differences to known taxa, the chondrichthyans from the Paris Biota are provisionally kept in open nomenclature, as Hybodontiformes gen. et sp. indet. A and Hybodontiformes gen. et sp. indet. B, respectively. The present study adds a new occurrence to the chondrichthyan fossil record of the marine Early Triassic western USA Basin, from where other isolated teeth (Omanoselache, other Hybodontiformes) as well as fin spines of Nemacanthus (Neoselachii) and Pyknotylacanthus (Ctenachanthoidea) and denticles have been described previously.  相似文献   

5.
Three new ichnogenera and five new ichnospecies are described for new trace fossils of termitaria (including associated gallery systems) of subterranean termites from upper Eocene through lower Miocene rocks of northern Egypt. All but two ichnospecies (Krausichnus trompitus, ichnogen, and ichnosp. nov., and A’, altus, ichnosp. nov.) show varying degrees of affinity to nests of the extant subterranean termite species Sphaerotermes sphaerothorax (Termitidae, Macro‐termitinae).

Termitichnus qatranii (Bown, 1982) is divided into two ichnospecies, the previously named T. qatranii, and a more generalized form, T. simplicidens, ichnosp. nov. Vondrichnus obovatus, ichnogen. and ichnosp. nov., is named for simple, possibly macrotermitine nests with oblate form, and Fleaglellius pagodus, ichnogen. and ichnosp. nov., records a nest form similar to V. obovatus, but one in which successive vertical growth by chamber apposition has produced a subterranean, tower‐like structure, reminiscent of that built by extant, epigeous Cubitermes. Krausichnus trompitus, ichnogen. and ichnosp. nov., and A’, altus, ichnosp. nov., record two unique nest architectures probably produced by unknown but related species of humivorous termites. The nest architecture expressed by Krausichnus is of wholly unknown affinity and is only distantly related in form to the ichnofossils of other termite nests known from the Tertiary of Egypt.

Study of the architecture of the nests of these ancient termites reveals details important in reconstructing the phylogeny of termite nests and documents two novel blueprints for chamber expansion and society budding in what were probably primitive Macrotermi‐tinae. It also indicates that at least two constructed edifices, earlier known only as epigeous manifestations of extant termite species, were almost certainly first developed by species living underground.

The extant Macrotermitinae are a subfamily of termites originally believed to have evolved in the post‐Eocene of the Ethiopian biogeo‐graphic region. We offer fossil evidence of four distinct, possibly macrotermitine structures from upper Eocene rocks. This evidence suggests that this termite subfamily (or at least their peculiar mode of nest construction) might have evolved considerably earlier, as it is already well established and exhibits several variants by the late Eocene in Egypt.  相似文献   

6.
《Comptes Rendus Palevol》2018,17(7):435-442
Three new localities yielding fossiliferous flints are reported from the Châtellerault area (Vienne, western France). They include one archaeological site (La Grande Vallée) and two zones with alterite deposits (L’Aunas and Les Bariollières). Broken surfaces of flint nodules show co-occurrence of marine invertebrates such as bryozoans, echinoids (Micraster Agassiz, Orthopsis Cotteau), gastropods (Acteonella d’Orbigny), rudists, and sponges. The association of Acteonella, Micraster and Orthopsis confirms the Turonian age (Upper Cretaceous) of the fossil assemblage. The marine invertebrates co-occur with plant macroremains including fragments of conifer leafy axes such as Brachyphyllum? Brongn., Frenelopsis (Schenk) emend. J. Watson and Geinitzia Endl., as well as fragments of angiosperm leaves. Plant remains are preserved as siliceous permineralizations, showing the gross morphology and all tissues in three dimensions. The fossil assemblage suggests that sediments were deposited proximally along the shoreline in shallow environment influenced by both continental and marine inputs. This coastal area was close to a conifer-dominated forest ecosystem, Geinitzia being probably one of the main components of the flora.  相似文献   

7.
Floral initiation and development of Hedysarum varium, Onobrychis melanotricha and Alhagi persarum was studied using epi-illumination light-microscopy techniques. The studied species belong to the tribe Hedysareae of the inverted repeat loss clade (IRLC clade), which is characterized by missing the large inverted repeat in the chloroplast genome. The main aim of our study was to determine developmental bases for similarities and differences among the three taxa and to verify the position of Alhagi relative to other genera of the IRLC clade. According to our observations, bracteoles are missing in Onobrychis melanotricha, but are present in the other two species. All three species share unidirectional sepal initiation starting with a median abaxial sepal and bidirectional petal initiation. Stamen initiation is unidirectional in all except in the outer stamen whorl of Hedysarum varium, where it is bidirectional. An important ontogenetic feature in O. melanotricha is the existence of five common primordia, which give rise to petal and stamen primordia. Although in H. varium and O. melanotricha common primordia are observed at some stages in floral organ initiations, in Alhagi all organs are initiated separately. Moreover, overlap in time of floral organs initiation occurs in H. varium and O. melanotricha, but not in A. persarum. The carpel initiates concurrently with the petal primordia in all. It might be presumed that Alhagi is primitive in relation to the other studied Hedysareae taxa, due to the presence of bracteoles, the absence of common primordia, and the lack of overlap in time of different organ initiations.  相似文献   

8.
Among several highly fossiliferous localities in the Bloubank Valley (Gauteng, South Africa), the Cooper's Cave System has been known since 1938 and has produced a rich fossil assemblage, including some remains of the early hominin Paranthropus robustus. In 2001, excavations began at a new locality, Cooper's D, which dates to ~1.4-1.5 Ma. Although hominins are relatively rare in the assemblage, remains of cercopithecoid primates are much more common. Craniodental fossils currently indicate the possible presence of at least three large-bodied cercopithecoid primate genera at Cooper's D: Gorgopithecus, Papio, and Theropithecus. In this study, we identify and describe > 100 cercopithecoid primate postcranial fossils representing all regions of the appendicular skeleton. The specimens come from several age classes and size morphs; more than one third of the fossils described are from sub-adult and juvenile individuals. The adult postcranial fossils vary substantially in size, with body masses estimated between 30 and 60 kg (from 16 of the better preserved specimens). The functional morphology of the postcranial remains indicate that these elements come from animals that likely utilized terrestrial substrates, but they remain difficult to definitively attribute to Gorgopithecus, Theropithecus, or Papio given the absence of associated skeletons. The smaller specimens likely belong to Papio while the larger ones can be attributed to the other two genera. Because Cooper's D has also yielded fossils of the early hominin Paranthropus robustus, this raises the question of how these four large-bodied, mostly terrestrial primates sympatrically utilized the landscape.  相似文献   

9.
We report the study of the collection of fossil bovid specimens from the Early-Middle Pleistocene Acheulian site of Gesher Benot Ya‘aqov. This locality, situated in the Levantine Corridor (the bottleneck that connects Africa and Eurasia) is a key site to explain the faunal and human dispersals out of Africa during the Matuyama/Brunhes boundary around 0.8 Ma. Two species of bovine (Bos sp., and Bovini gen. et sp. indet. cf. Bison sp.), one antelope (Gazella sp. cf. G. Gazella), and another indeterminate Bovidae gen. et sp. indet., have been recorded. The largest species, Bos sp., is an African immigrant related to the species from the Eritrean site of Buia, Bos buiaensis, which evolved from the buffalo of Olduvai Pelorovis oldowayensis, and colonized the Eurasian continent in parallel with the dispersal of the Acheulian culture into the northern continent. Numerous important species first recorded in several localities of Early-Middle Pleistocene transition from Eurasia are included in this dispersal out of Africa, including the megaherbivore, Palaeoloxodon antiquus, and the carnivores Crocuta crocuta, and later, Panthera leo and Panthera pardus. This faunal turnover is coincident with the change to colder climates that dominated the Middle Pleistocene.  相似文献   

10.
Abstract—Morphology and histology of several fragmentary turtle specimens from the Middle Jurassic locality in the Berezovsk quarry (Krasnoyarsk Region, Russia) are described, including Testudines indet. 1 (costal VIII), Testudines indet. 2 (two ornamented shell fragments), and Testudines indet. 3 (distal part of a humerus), and also skeletal elements of Annemys sp. (Xinjiangchelyidae) represented by mass material in the same locality. It is shown that Testudines indet. 1 and 3 probably belong to one or two taxa of basal aquatic turtles, while Testudines indet. 2 is most likely an abnormal Annemys sp. The presumable presence of basal turtles in the Berezovsk Quarry Assemblage agrees with the fact that they are present in other Middle Jurassic turtle assemblages of Asia.  相似文献   

11.
We present a first look at the microvertebrate fauna of the Middle Pleistocene site of Hummal in Central Syria. Some 2000 microvertebrate remains (1200 mammalian; 230 reptilian; 600 unidentified) were found in unit G/layer 17 by screen-washing sediments in an area of 4 m2. The following taxa have been identified: Reptilia: Agaminae indet., Gekkota indet., Lacertidae indet. (2–3 taxa), Eryx sp., Natricinae indet.; and Mammalia: Crocidurinae indet., Chiroptera indet., Lepus sp., Arvicolinae indet., Ellobius sp., Microtus sp., Murinae indet. (large form), Mus sp., Meriones sp., Gerbillus sp. The presence of Ellobius indicates a Middle Pleistocene age of the fauna. This genus does not occur in Syria today, but is recorded in Israel in Late Acheulean to Early Mousterian sites. In North Africa, the occurrence of this genus is restricted to the early part of the Middle Pleistocene. The ecological requirements of the nearest living relatives of the recorded taxa indicate mainly open habitats, but also the presence of vegetation and wet conditions, at least close to the site. Lepus, Ellobius, Meriones, Gerbillus, and Eryx live to various extents in steppes, semi-deserts, and deserts. Various extant species of large murids that come into consideration occupy a variety of wooded habitats, grassland and savannah and require the presence of water. Hummal offers the most detailed Pleistocene portrait yet of hominin palaeoenvironment in an area that, at the end of the Pleistocene, became known as part of the Fertile Crescent.  相似文献   

12.
Ankylosaurian remains from the Transylvanian Basin, Romania, are extremely rare. More than 100 years after the discovery of the first and only better-known assemblage, namely the type material of Struthiosaurus transylvanicus, new ankylosaurian material has been discovered in the Maastrichtian of the Ha?eg Basin, as well as at another locality (Vurp?r), in the Transylvanian Basin, that is described here. The material consists of one tooth in a small jaw fragment (from the Ha?eg Basin) and at least two accummulations of associated, as well as several isolated, postcranial elements (from Vurp?r). No diagnostic elements are preserved that would overlap with the type of Stransylvanicus, so we cannot assign any of the new specimens to this species. The tooth shows marked differences compared to those of other anklyosaurs including S. austriacus and Hungarosaurus in having only six, more or less equally sized, apically pointed cusps separated by deep grooves. The postcranial material from Vurp?r represents at least three different individuals. The humerus is the most diagnostic element among the postcranial remains being most similar both in size and morphology to humeri referred to as Struthiosaurus from different European localities, thus here we refer the humerus and probably associated elements preserved in one assemblage to as cf. Struthiosaurus sp.; the remaining specimens from Vurp?r are retained as Nodosauridae indet. Histological studies have confirmed the adult nature of all sampled bones in the Vurp?r ankylosaur material suggesting that these fully grown animals were of similar size to Struthiosaurus, a small-bodied nodosaurid the ontogenetic status of which, however, has never been investigated histologically. The obviously diminished body size of the Transylvanian ankylosaurs compared to other members of the clade could be explained by insular dwarfism using the same histology-based argument as presented for Magyarosaurus.  相似文献   

13.
Preliminary results of the investigation of the microfauna at the Acheulo-Yabrudian Middle Pleistocene site of Qesem Cave, Israel, are presented. Thus far the assemblage includes ca. 10,000 bone and tooth fragments, of which 50% could be identified to the generic and some hundreds to the species level. Based on the current material, the fauna includes the following squamate reptiles: Laudakia sp., Chamaeleo sp., Gekkonidae indet., Lacertidae indet., Scincidae indet., Pseudopus sp., Varanus sp., Colubroidea indet. (at least three species) and micromammals: Suncus etruscus, Crocidura cf. leucodon, Crocidurinae indet. (large form), Chiroptera indet., Sciurus cf. anomalus, Cricetulus cf. migratorius, Microtus guentheri, Nannospalax ehrenbergi, Dipodillus cf. dasyurus, Meriones cf. tristrami, Gerbillidae indet., Mus cf. musculus, Apodemus cf. flavicollis. These results suggest that the fauna includes only taxa that occur recently in the territory of Israel. The ecological preferences of the nearest living relatives of the recorded taxa allow us to infer a paleoenvironment with a mosaic of open and woodland habitats. However, comparing the lower with the upper levels of the microfauna-bearing profile, a slight shift towards more wooded conditions might be detectable. Biostratigraphical inferences from the recorded micromammal taxa cover a rather wide age range, whereas the radiometric (U-series and preliminary TL) dating enable a provisionally estimated date for the microfauna-bearing levels at 360-300 ka. Detailed morphometric comparisons with material from other sites in the region are necessary and may yet provide further insights.  相似文献   

14.
The Upper Barremian (Lower Cretaceous) site of Las Hoyas (Spain) is an important Konservat Lagerstätte that has a yielded well-preserved biota. Both the palaeohistology and the preservation of six tetrapods were investigated in this study. Chemical analysis (Ca/P ratio, fluorine, strontium, barium and REE amounts) reveals an alteration of the original apatite of the bone in fluoroapatite by postmortem substitutions, a late Sr incorporation during fossilization, and a rather moderate postmortem REE incorporation in the freshwater environment of Las Hoyas. However, the conditions of fossilization have limited the dissolution-recrystallisation processes and preserved the microstructure of the bones. Bone growth rate estimations have been made according to Amprino's rule. The Discoglossidae indet, the Centrocryptodira indet. and Scandensia ciervensis are characterized by low growth rates and an ectothermic metabolism. Concornis lacustris, Pelecanimimus polyodon and the Archosauria indet. are characterized by a faster growth and probably higher resting metabolic rate. All of the specimens are adults of small-sized species. This leads to the hypothesis of an ecological filter favoring small-sized species in this ecosystem, strengthening the taphonomical results. The combination of geochemical and histological studies seems to offer a more precise overlook of life history traits and preservation of these fossils from Las Hoyas.  相似文献   

15.
Bioerosion is a common process in hard substrates. This study introduces an example from the rocky palaeoshore cropping out at a sea cliff on the Bozcaada Island. It includes bioerosion trace fossils preserved in limestone boulders of the shallow marine and lacustrine Alcitepe Formation of Late Miocene age. The ichnotaxa include borings produced by duraphagous drillers (Oichnus isp.), phonorids (cf. Conchotrema isp.), clionid sponges (Entobia cf. goniodes, Entobia geometrica, Entobia laquea, Entobia ovula, E. cf. solaris, Entobia isp.), endolithic bivalves (Gastrochaenolites torpedo, Gastrochaenolites lapidicus, Gastrochaenolites isp., Phrixichnus isp.), polychaete annelids (Maeandropolydora isp., Maeandropolydora sulcans, Maeandropolydora decipiens, Caulostrepsis taeniola, Caulostrepsis isp.), echinoids (cf. Circolites isp.) and spinculid worms (cf. Trypanites isp.). Barnacles are also common as encrusters. The borings can be ascribed to the Gastrochaenolites-Entobia assemblage, which is typical of Neogene rocky-shores. They belong to the Entobia ichnofacies indicating various conditions of light, energy, and depth. Therefore they can reveal environmental changes and play an important role in forming palaeo-rocky shores and wave-cut platforms during marine trangressive events.  相似文献   

16.
17.
18.
Upper Jurassic (Kimmeridgian–Tithonian) and Cretaceous (Berriasian–Barremian) strata of the Ukrainian part of the Carpathian Foredeep basement are rich, at least locally, in crinoid remains. Crinoids belonging to cyrtocrinids (Cyrtocrinida) are represented by whole cups, isolated remains of disarticulated cups, brachial plates and columnals. They are assigned to the following taxa: Cyrtocrinida indet., Eugeniacrinites cf. cariophilites (von Schlotheim), Lonchocrinus sp., Phyllocrinus stellaris Zaręczny, Ascidicrinus pentagonus (Jaekel), Gammarocrinites sp., Psalidocrinus armatus (Zittel), Psalidocrinus sp., and Hemibrachiocrinidae gen. indet. Cyrtocrinids are associated with other stalked (isocrinids, Isocrinida and millericrinids, Millericrinida) and stemless (saccocomids, Roveacrinida) crinoids. Columnals, pluricolumnals, brachial plates, and cirrals of isocrinids are assigned to Balanocrinus sp., Isocrinina fam. et subfam. indet., and columnals of millericrinids to Millericrinida indet. Free-living roveacrinids are assigned to Saccocoma sp. and Crassicoma sp. Knowledge on Jurassic and Cretaceous crinoids formerly described from Ukraine is discussed. Although majority of crinoids described herein seems to be allochthonous, autochthonous forms were also found with certainty in some intervals. These include some cyrtocrinids, which dominate in shallow-water environments of the Ukrainian Carpathian Foredeep basement. Isocrinids are also common in this shallow marine environment, whereas sessile saccocomids are assigned to low-energy, mud-supported bottom, open marine, outer-platform/upper slope, and relatively deep environments.  相似文献   

19.
《Annales de Paléontologie》2017,103(3):223-233
The « Marnes et calcaires lumachelles à huîtres » Formation (late Albian–early Cenomanian) of the South Riffian Ridges, rich in bivalves, yielded in levels of upper Albian some gastropod specimens including: Ampullina aff. uchauxiensis Cossmann, Ampullina indet., Aporrhaidae indet., Calliomphalus cf. orientalis (Douvillé), Cerithioidea indet., Mrhilaia indet.,?Neogastropoda indet., Pleurotomaria indet., Pseudamaura subbulbiformis (d’Orbigny), Tylostoma aff. globosum Sharpe, and a rare bivalve, Pinna (Pinna) cretacea cretacea (Schlotheim). The two underlying formations « Conglomérat et marnes sableuses » and « Calcaires gréseux » (early to middle Albian?), poor in macrofauna, yielded rare Nerineopsis aff. excavata (Brongniart) and Turritella indet. These species are reported for the first time in the Moroccan Cretaceous deposits.  相似文献   

20.
The bacterial aerobic respiratory chain has a terminal oxidase of the heme-copper oxidase superfamily, comprised of cytochrome c oxidase (COX) and ubiquinol oxidase (UOX); UOX evolved from COX. Acetobacter pasteurianus, an α-Proteobacterial acetic acid bacterium (AAB), produces UOX but not COX, although it has a partial COX gene cluster, ctaBD and ctaA, in addition to the UOX operon cyaBACD. We expressed ctaB and ctaA genes of A. pasteurianus in Escherichia coli and demonstrated their function as heme O and heme A synthases. We also found that the absence of ctaD function is likely due to accumulated mutations. These COX genes are closely related to other α-Proteobacterial COX proteins. However, the UOX operons of AAB are closely related to those of the β/γ-Proteobacteria (γ-type UOX), distinct from the α/β-Proteobacterial proteins (α-type UOX), but different from the other γ-type UOX proteins by the absence of the cyoE heme O synthase. Thus, we suggest that A. pasteurianus has a functional γ-type UOX but has lost the COX genes, with the exception of ctaB and ctaA, which supply the heme O and A moieties for UOX. Our results suggest that, in AAB, COX was replaced by β/γ-Proteobacterial UOX via horizontal gene transfer, while the COX genes, except for the heme O/A synthase genes, were lost.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号