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1.
A chimaerid holocephalian, Chimaera zangerli sp. nov., is described from both palatine tooth plates, two tooth plate fragments, and part of the chondrocranium in a nodule from the Maastrichtian of Antarctica. Possibly the oldest known chimaerid, C. zangerli sp. nov. exhibits a tooth plate which is a morphological intermediate between that of the Jurassic Ganodus and the Oligocene C. rupeliensis . The presence of C. zangerli sp. nov. before the end of the Cretaceous is evidence of the early evolution of the Chimaeridae, considered the most derived of the chimaeroid fishes.  相似文献   

2.
The wood flora from Williams Point, Livingston Island, contains 12 wood types of gymnosperm and angiosperm origin. Recent collections of material have increased the biodiversity of a postulated species-rich vegetation. The gymnosperm wood can be readily assigned to four form-genera: Araucarioxylon Kraus, Araucariopitys Jeffrey, Podocarpoxylon Gothan and Sahnioxylon Bose and Sah. This indicates a diversity of coniferous araucarian and podocarp trees alongside woods of uncertain affinity ( Sahnioxylon ; Bennettitales). Two angiosperm morphotypes are assigned to the organ genera Hedycaryoxylon Su¨ss (Monimiaceae) and Weinmannioxylon Petriella (Cunoniaceae). The remaining four taxa of angiosperm wood cannot be confidently placed in extant families as they exhibit features that suggest relationships with the Magnoliidae, Hamamelidae and Rosidae. This paper presents the first comprehensive taxonomic revision of the wood flora from Livingston Island and discusses the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous. Newly described taxa are Araucarioxylon chapmanae sp. nov., Araucariopitys antarcticus sp. nov., Podocarpoxylon chapmanae sp. nov., P. verticalis sp. nov., P. communis sp. nov., Weinmannioxylon ackamoides sp. nov., Antarctoxylon livingstonensis gen. et sp. nov., A. multiseriatum gen. et sp. nov., A. heteroporosum gen. et sp. nov. and A. uniperforatum gen et sp. nov.  相似文献   

3.
A new species of carcineretid crab, Carcineretes planetarius, is described from the Upper Cretaceous (lower Maastrichtian) Barton Creek Dolomite at Albion Island, Belize. The age is based on the stratigraphic range of associated nerineid gastropods and correlation with nannoplankton, benthic foraminifera, and the other known congeneric species of crab found in Jamaica. Confirmation of this age aids in constraining the timing of ejecta deposits of the Chicxulub impact found at the top of Barton Creek Dolomite exposed on Albion Island. Paleoenvironmental and paleoecological analyses suggest that these crabs were swimmers in lagoonal settings, capable of burrowing a few centimeters into the mud for protection.  相似文献   

4.
We report excavations of an abandoned penguin colony on Byers Peninsula, Livingston Island, Antarctica, in austral summer 2008/2009. Nine abandoned pebble mounds were located on Devils Point, near an active Gentoo Penguin (Pygoscelis papua) colony of about 3,000 nests, at an elevation of 40–45 m above sea level. Three of the nine mounds were excavated to recover organic remains for radiocarbon and ancient DNA analyses; two additional mounds were probed to obtain tissue samples for additional dating. All radiocarbon dates were corrected for the marine-carbon reservoir effect using a ΔR of 700 ± 50 years. Calibrated 2-sigma ranges in calendar years before present (B.P.) on 23 samples of egg membrane and bone provided an overall range of 40–1,150 B.P., with most of the dates falling between 225 and 465 B.P. Ancient DNA analysis confirmed that the tissues recovered from these excavations represent Gentoo Penguin. One radiocarbon date from the active Gentoo Penguin colony indicated an age of 285–480 B.P. for the initiation of this current occupation and corresponding in age with most of the abandoned mounds. Although geologic evidence indicates that Byers Peninsula has been ice free for at least 3,000 years, these results indicate that penguin occupation lagged behind deglaciation by over 2,000 years. Small numbers of Chinstrap Penguins (P. antarctica) also occupy the same breeding colonies as Gentoo Penguins at Byers Peninsula, but their absence in the ancient sediments suggests that they have only recently colonized this area.  相似文献   

5.
Abstract: Two extraordinarily well‐preserved testate amoebae are described from Late Albian age amber from south‐western France. The specimens are attributed to a new family, the Hemiarcherellidae fam. nov., and are described as Hemiarcherella christellae gen. et sp. nov. The amoebae described herein originate from highly fossiliferous amber pieces. Based on syninclusions, Hemiarcherella christellae was a soil‐dwelling organism, probably an active bacterivore. This taxon represents the third species of testate amoebae described from mid‐Cretaceous French amber. Analysis of this fossil amoeba fauna illustrates the uniqueness of mid‐Cretaceous French amber deposits. Indeed, most amoebae found in amber have been assigned to modern species, corroborating the hypothesis of morphological stasis in different microbial lineages. However, the well‐preserved amoebae fauna found in French amber can be distinguished clearly from modern species and help us to better understand the fossil record of these organisms.  相似文献   

6.
For the first time a detailed stratigraphic section of the Lower Cretaceous (Albian) of Cabo de Ajo peninsula (Cantabria Province) is logged. The Ajo facies represents a subtropical shallow-water carbonate platform environment. When the platform was subjected to relatively high-energy conditions, calcarenite skeletal shoals developed. In periods of higher sealevel, deeper-water marls were deposited in intraplatform basins. The outcrops yield abundant fossils of scleractinian corals. Three selected stratigraphic horizons containing corals were sampled. Fauna 1 and 2 grew on a shallow-water soft bottom substrate (marl) below wave-base level and contain very small plocoid and phaceloid growth forms. Fauna 3 is associated with a calcarenitic matrix and large forms suggesting a more agitated and wave-influenced environment. 16 species of corals belonging to 7 suborders are described taxonomically. These rather diverse coral associations are among the youngest from the Urgonian facies of Europe, and compare well with other Urgonian Tethyan faunas.  相似文献   

7.
Three new taxa from Albian, Early Cretaceous assemblages in Gondwana (Australia and Antarctica) and two previously described fossils from the Late Cretaceous and Eocene of North America are attributable to the heterosporous semi-aquatic fern family Marsileaceae. They are assigned to Marsileaceaephyllum, a morphotaxon erected here for sterile remains (whole plants, and isolated leaves and leaflets) of Marsileaceae. The Gondwanan taxa, Marsileaceaephyllum lobatum and Marsileaceaephyllum spp. B-C, have either a cruciform leaflet arrangement or dichotomous and anastomosing venation characteristic of modern Marsileaceae. Two previously established taxa, Marsilea johnhallii and Marsilea sp., which represent sterile Marsileaceae, are also transferred to the new genus (now Marsileaceaephyllum johnhallii and Marsileaceaephyllum sp. A, respectively). Examination of all fossil venation patterns reveals four new venation types not present in extant taxa, suggesting that most fossil Marsileaceae (leaves) are distinct from extant genera, and are likely members of extinct lineages. This is further supported by the absence of modern megaspore types in the Early Cretaceous.  相似文献   

8.
Twenty-three species of benthic hydroids, belonging to eight families and 13 genera, were found in a hydroid collection from Peter I Island, collected during both the Bentart 2003 and Bentart 2006 Spanish expeditions with BIO Hespérides in 2003 and 2006. Fourteen out of the 23 species constitute new records for Peter I Island, raising the total number of known species in the area to 30, as also do seven out of the 13 genera. The majority of the species are members of the subclass Leptothecata; the subclass Anthoathecata being scarcely represented. Sertulariidae is the family with the greatest number of species in the collection, with eight species (35%), followed by Lafoeidae with five (22%). Symplectoscyphus with four species (17%) and both Antarctoscyphus and Halecium with three (13%), including H. frigidum sp. nov., were the most diverse genera. Twenty species (ca. 77%) are endemic to Antarctic waters, either with a circum-Antarctic (11 species, ca. 42%) or West Antarctic (9 species, ca. 35%) distribution. Twenty-four (ca. 92%) are restricted to Antarctic or Antarctic/sub-Antarctic waters; only two species have a wider distribution. Peter I Island hydroid fauna is composed of typical representatives of the Antarctic benthic hydroid fauna, though it is characterized by the low representation of some of the most diverse and widespread Antarctic genera (Schizotricha and Staurotheca).  相似文献   

9.
The paleobiology of the Cretaceous neoselachian shark,Squalicorax, has largely been based on isolated teeth. We examined partial and nearly complete skeletons of three species ofSqualicorax, S. falcatus (Aoassiz),S. kaupi (Agassiz), andS. pristodontus (Agassiz), that were collected from the U.S.A. These specimens suggest that the total body length (TL) ofS. falcatus typically measured 1.8–2.0 m, and probably did not exceed 3 m. Moderatesized individuals ofS. kaupi andS. pristodontus perhaps measured about 3 m TL. AlthoughS. pristodontus was the largest form among the three species examined, this taxon possessed a set of large jaws (with large but fewer teeth) relative to its body size compared toS. falcatus orS. kaupi. This suggests that tooth size is not an accurate indicator of the TL if one compares oneSqualicorax species to another. Neurocranial features suggest that the vision ofSqualicorax was not as acute as that of a contemporaneous macrophagous lamniform shark,Cretoxyrhina mantelli (Agassiz) , but olfaction ofSqualicorax may have been better thanC. mantelli. The morphology of placoid scales suggests thatSqualicorax was capable of fast swimming. New skeletal data support the view that the feeding dynamics ofSqualicorax was similar to the modern tiger shark (Galeocerdo Müller & Henle). The present data do not allow for exact ordinal placement, but, contrary to some previous interpretations,Squalicorax can be excluded from the Hexanchiformes and Orectolobiformes. The taxon should more appropriately be placed within the Lamniformes or Carcharhiniformes.   相似文献   

10.
《Palaeoworld》2016,25(3):425-430
Cretaceous evaporites of the Maha Sarakhan Formation in Thailand (e.g., the Nongbok Formation, Laos) have been studied for almost a century as the huge potash deposits in the world. The consistently high local paleotemperatures should lead to huge salt deposits during the evaporation process. Primary fluid inclusions in halite can provide surface brine water temperatures directly and quantitatively. Until now, there have been no data published from paleotemperature of primary fluid inclusions of Cretaceous halite. The non-marine halite from the Cretaceous Nongbok Formation (Laos) precipitated from shallow brine waters with temperatures of 17.7–42.3 °C.  相似文献   

11.
Collections of leaves of the genus Paraprotophyllum Herman amassed by Heer and Kryshtofovich from Sakhalin Island are revised. The morphology and variability of P. schmidtianum (Heer) Golovneva, comb. nov. are analyzed.  相似文献   

12.
Zuluscaphites van Hoepen 1955, an enigmatic ammonite originally described from the Middle or Upper Albian of Zululand, South Africa, is shown to be a member of the acanthoceratacean family Lyelliceratidae, subfamily Stoliczkaiinae; it is not a heteromorph as originally proposed. Huescarites Latil 1991 is a junior synonym of Zuluscaphites as are the type species of the two genera, Z. orycteropusi and H. companyi.  相似文献   

13.
The new enchytraeid species Lumbricillus healyae sp. n. is described from freshwater streams, with well-oxygenated and poorly mineralised waters, situated in Byers Peninsula (Livingston Island, South Shetland Islands, Antarctica). Lumbricillus healyae sp. n. is morphologically close to L. antarcticus and L. incisus, and it is mainly distinguished by the structure of the spermatheca with a short, distinct ectal duct, the oval penial bulb (greatest diameter in the transverse body axis) associated with strong dorso-ventral muscular fibres, and a protrusible pseudopenis. A second undetermined Lumbricillus species is described from a small stream. Study specimens are not fully mature; however, the highly irregular form and size of the testis-sac lobes and the absence of a penial bulb encapsulated under a muscular layer are remarkable. It is probably related to a small group of Lumbricillus species reported from the Antarctic maritime region (L. colpites, L. griseus and L. aestum), characterised by the structure of the male duct, which ends in a simple pore surrounded by glands.
Eugenio RicoEmail:
  相似文献   

14.
Summary The species composition of the ichthyofauna of Admiralty Bay, King George Island was determined from results of sampling using bottom trawls, gill-nets and long-lines. Thirty-five species from 24 genera and 10 families (Table 1) were found. The number of species increased with depth (e.g. 7 species at 100 m, 14 species at 255 m and 21 species at 540 m), a tendency characteristic of Antarctic waters. In the bay, the catch rate obtained with a bottom trawl (greater than 30 kg/h) was roughly ten times lower than the catch rate using the same gear on the shelf around the Island. Notothenia gibberifrons was the dominant species in all trawls. The majority of these fish (about 95%) were immature juveniles (Table 4). Younger fish were found to inhabit shallower waters (Fig. 1). The majority of the fish of species Notothenia coriiceps neglecta, Notothenia rossii marmorata, Notothenia nudifrons, Trematomus newnesi and Trematomus bernacchii preferred waters about 255 m deep. Fourteen specimens of a previously undescribed species of the genus Psilodraco (currently being described by H. DeWitt) were caught in the bay within the 146 to 540 m depth range. The rare zoarcid, Lycenchelys aratrirostris, was also caught in Admirality Bay; previously this species had only been reported from the Elephant Island region. In the case of Trematomus newnesi, the occurrence of scales in the interorbital space was noted (Fig. 2), an observation which verifies this feature as a distinct taxonomical criterion for this species.  相似文献   

15.
Eleven veneroid (Bivalvia) species are systematically described from the Campanian-Maastrichtian (Late Cretaceous) sediments of Ariyalur sub-basin of South India. Among these, only Crassatella (Crassatella) macrodonta (Sowerby) and Arctica lacianata (Stoliczka) were earlier recorded by Stoliczka. Protocardia (Pachycardium) madagascariensis (Colignon), Protocardia (Pachycardium) pauli (Cocquand), Epicyprina angulata (Sowerby), Venilicardia truncata (Sowerby), and Calva (Egelicalva) buttensis (Anderson) were previously unknown from the Late Cretaceous horizons of the Indian sub-continent. The present record also includes a new species Palaeomoera stoliczkai n. sp. erected on the basis of its unique hinge characters and surface features. Lucina (Lucina) cf. fallax Forbes, Nicaniella (Nicaniella) aff. trigonoides (Stoliczka), and Corbicula? sp. indet., are tentatively identified because of their imperfect preservation. The present record may add useful information to the understanding of the Late Cretaceous palaeobiology of the region.  相似文献   

16.
The blackfly Simuliites yantardakh sp. nov. from the Taimyr amber is described. It is distinguished from the only known Late Cretaceous blackfly from the New Jersey amber Archicnephia ornithoraptor Currie et Grimaldi by the twice larger size, the short pubescent antenna, only slightly expanded antennomeres 1 and 2; the small palpomere 3, which is 1.5 times as wide as palpomere 4; and the shorter mouth appendages.  相似文献   

17.
The spatial and temporal variation of microphytobenthic biomass in the nearshore zone of Martel Inlet (King George Island, Antarctica) was estimated at several sites and depths (10–60 m), during three summer periods (1996/1997, 1997/1998, 2004/2005). The mean values were inversely related to the bathymetric gradient: higher ones at 10–20 m depth (136.2 ± 112.5 mg Chl a m−2, 261.7 ± 455.9 mg Phaeo m−2), intermediate at 20–30 m (55.6 ± 39.5 mg Chl a m−2, 108.8 ± 73.0 mg Phaeo m−2) and lower ones at 40–60 m (22.7 ± 23.7 mg Chl a m−2, 58.3 ± 38.9 mg Phaeo m−2). There was also a reduction in the Chl a/Phaeo ratio with depth, from 3.2 ± 3.2 (10–20 m) to 0.7 ± 1.0 (40–60 m), showing a higher contribution of senescent phytoplankton and/or macroalgae debris at the deeper sites and the limited light flux reaching the bottom. Horizontal differences found in the biomass throughout the inlet could not be clearly related to hydrodynamics or proximity to glaciers, but with sediment characteristics. An inter-summer variation was observed: the first summer presented the highest microphytobenthic biomass apparently related to more hydrodynamic conditions, which causes the deposition of allochthonous material.  相似文献   

18.
The Albian sediments of the Transdanubian Range in Hungary were deposited in non-marine to fully-marine environments. The studied sections revealed diverse benthic ostracod faunas with moderately-preserved specimens. Forty-six taxa are identified and Cypridea zalanyii n. sp. is newly described. The detailed palaeoecological study of these ostracod faunas provided an opportunity to distinguish eight assemblages. The assemblages include limnic, brackish lagoon, shallow marine, reef and low oxygenated semi-enclosed basin environments in the Northern Tethys region we investigated. This work contributes to the knowledge about Albian non-marine faunas from Europe and explores ecological requirements of brackish faunas.  相似文献   

19.
20.
A new genus and new species of lindholmemydid turtle (Cryptodira: Testudinoidea), Shandongemys dongwuica n. g. and n. sp. are described on the basis of a partial skeleton with incomplete shell and skull, complete lower jaws and disarticulated limb bones from the Upper Cretaceous Wangshi Group of Zhucheng, Shandong Province, China. Among Lindholmemydidae, the new species is closely related to Mongolemys elegans from the Late Cretaceous of Mongolia. An incomplete shell from the same locality is referred as Lindholmemydidae indet. Glyptops sp. from the Upper Cretaceous Wang Group of Jingangkou, Laiyang, Shandong is revised and assigned to Lindholmemydidae.  相似文献   

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