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1.
Although five genera of procyonids are currently present in South America, only two of the extant genera, Procyon and Nasua are represented in the South American fossil record. A recent discovery of a procyonid lower second molar in Late Pleistocene deposits of Aurora do Tocantins, northern Brazil, offers potential to further our understanding of the stratigraphic and temporal range of South American fossil procyonids. We use geometric morphometric analysis of two-dimensional landmarks and semilandmarks to explore morphological variation in the lower second molars of extant Procyon lotor and Procyon cancrivorus and multivariate methods to support the identification of the Pleistocene specimen as P. cancrivorus. This material represents the second fossil record of P. cancrivorus in South America Procyonids entered South America in two phases: the first comprising by Cyonasua and Chapadmalania during the Late Miocene, and the other recent genera, beginning in the Late Pleistocene. These Late Miocene procyonids were more carnivorous than Late Pleistocene-Recent omnivorous taxa and possible went extinct due to competition with other placental carnivorans that entered South America and diversified during the latest Pliocene-Early Pleistocene.  相似文献   

2.
The present study deals with the lithostratigraphy and planktonic foraminiferal biostratigraphy of the Late Eocene-Middle Miocene sequence in the Al Bardia area, northeast Libya. The lithostratigraphical studies carried out on three stratigraphical surface sections, namely Wade Al Rahib, Wadi Al Hash and Wadi Al Zeitun, led to the recognition of three rock units from base to top: (1) the Al Khowaymat Formation (Late Eocene-Early Oligocene); (2) the Al Faidiyah Formation (Late Oligocene-Early Miocene); and (3) the Al Jaghboub Formation (Early-Middle Miocene). The planktonic foraminiferal biostratigraphical analysis led also to the recognition of nine planktonic foraminiferal zones ranged in age from Late Eocene to Early Miocene with one larger foraminiferal zone of Middle Miocene age. These are, from base to top, as follows: Truncorotaloides rohri Zone (Late-Middle Eocene, Lutetian), Globigerinatheka semiinvoluta and Turborotalia cerroazulensis s.l. Zones (Late Eocene, Priaborian), Cassigerinella chipolensis/Pseudohasitgerina micra Zone (Early Oligocene, Rupelian), Globigerina ciperoensis ciperoensis, Globorotalia kugleri Zones (Late Oligocene, Chattian), Globigerinoides primordius Zone (Early Miocene, Aquitanian), Globigerinoides altiaperturus/Catapsydrax dissimilis and Globigerinoides trilobus Zones (Early Miocene, Burdigalian), and the larger benthonic foraminiferal zone, Borelis melo melo Zone (Middle Miocene, Langhian to Serravallian). The study of planktonic foraminifera proved the existence of a regional unconformity between the Early and Late Oligocene, with the Middle Oligocene deposits being absent (absence of Globigerina ampliapertura and Globorotalia opima opima Zones), and another, smaller unconformity located between the Late Eocene and Early Oligocene, in which the uppermost part of the Late Eocene is missing.  相似文献   

3.
《Gondwana Research》2014,25(3):1186-1201
The modern Koala Phascolarctos cinereus is the last surviving member of a once diverse family Phascolarctidae (Marsupialia, Phascolarctomorphia). Nine genera and at least 16 species of koala are known. Late Oligocene sediments of central Australia record the oldest fossils and highest species diversity. Five species are known from the early to middle Miocene rainforest assemblages of the Riversleigh World Heritage Area, Queensland. With the onset of dryer conditions after the middle Miocene climatic optimum (~ 16 Ma), rainforest habitats contracted resulting in the apparent extinction of three koala lineages (Litokoala, Nimiokoala, Priscakoala). Phascolarctos first appears in the fossil record during the Pliocene and the modern species around 350 ka. Despite a dramatic decline in taxonomic diversity to a single extant species, the fossil record indicates that at most only three koala species coexisted in any given faunal assemblage throughout their 24 million year history. Within these assemblages, the vast majority of extinct koalas are extremely rare (some known from only a single specimen) which may reflect a general rarity within their palaeohabitats compared with the modern species which is represented by an estimated 400,000 individuals spread over most of eastern mainland Australia. Be that as it may, P. cinereus, although once geographically more widespread, occurring for example in Western Australia in the Pleistocene, underwent significant range contractions and localized population extinctions during the stressful climatic conditions of the late Pleistocene and more recently through human-induced habitat destruction. Combined with threats of disease, reduced genetic diversity and climate change, the survival of this iconic Australian marsupial is arguably a cause for concern.  相似文献   

4.
While constraining Cenozoic evolution of the Himalaya through enlightening fossils we find that Dharmsala Group (intervening Subathu Group and Siwalik Group) in Kangra Valley and adjoining coevals yield sporadic fossils. Hence, this first record of fossil rodents from Dharmsala Group is an important addition to an earlier report of dinothere from these horizons. The rodent material from grey facies of the Dharmsala Group comprises of an isolated premolar and fragments of a tooth and an incisor. Available crown details in conjunction with distinctive dimensions of the premolar lead to its assignment to Hodsahibia, a baluchimyine taxon; this taxon of Eocene lineage of south Asian-African distribution is already on record from early Oligocene horizons in Bugti area, Pakistan.  相似文献   

5.
<正>Representatives of the extinct psocid family Empheriidae are known from Eocene Baltic amber, Lowermost Eocene French amber(Oise),and Lower Cretaceous Spanish amber(Alava).We report herein the first discovery of an empheriid psocid from the Cretaceous amber of New Jersey as Jerseyempheria grimaldii gen.et sp. nov.The fossil is figured and described.The new species is distinguished from related taxa.A discussion and checklist of Empheriidae are provided.  相似文献   

6.
The Eocene–Oligocene transition (EOT, ~34 Ma) is the largest global cooling of the Cenozoic Era and led the Earth's climatic system to change from a greenhouse to an icehouse mode. Although it is well documented in marine settings, the few studies focusing on continental environments have demonstrated regional heterogeneities. The study core CDB1, located in the Rennes Basin (Western France), is a unique terrestrial (lacustrine–palustrine) record comprising well‐preserved and terrestrial‐derived organic‐rich sediments encompassing the EOT. Clay minerals and the first organic nitrogen isotope record (δ15Norg) of terrestrial origin for this period are used to reconstruct palaeoclimate changes across this key interval. As suggested in worldwide marine and a few continental records, a stepwise transition from warm/humid conditions in the Late Eocene to cooler/drier conditions in the Early Oligocene is confirmed in the area. In addition, an episode of drier conditions in the Late Eocene and humid/dry cycles in the Early Oligocene are suggested.  相似文献   

7.
《Sedimentary Geology》1999,123(1-2):9-29
Sedimentological, biostratigraphic and magnetostratigraphic studies were carried out on five Late Eocene–Early Oligocene profiles in the Buda Hills, Hungary. The Szépvölgy Limestone Formation accumulated on the pre-Eocene basement. Basal strata of the limestone consist of a thin conglomerate followed by a coralgal limestone. The overlying limestone contains abundant Nummulites, Discocyclina. The contact between these two members is sharp. The Szépvölgy Limestone body, covering 60–65 km2, is considered a carbonate bank. Above the limestone, the siliciclastic slope deposits of the pelagic and turbiditic Buda Marl, and the euxinic Tard Clay accumulated. A huge multiphase hydrothermal cave system developed in the Szépvölgy Limestone resulting in a long-term composite palaeokarstic evolution lasting from the Late Eocene to the Quaternary. The first palaeokarst phase during the Late Eocene is represented by two generations of early marine cavity filling sediments of caymanite-type, deposited at sea-level. The earlier, carbonate infilling is conformable while the younger, siliciclastic one is disconformable with the bedding of the host rock. Bio- and magnetostratigraphic studies indicate that deposition of the caymanites-bearing palaeokarst host sequence started in the Late Eocene, during Chron C15r (35.3 Ma) and terminated in the Early Oligocene during Chron C13n (33 Ma). Two marker horizons are present, the first is between the Szépvölgy Limestone and Buda Marl at ∼34.6 Ma, and the second horizon is between the Buda Marl and the Tard Clay at 33.5 Ma. The Szépvölgy Limestone, deposited on a mobile shelf, represents a deepening upward sequence, interrupted by two lowstand events. They can be correlated with the PHd event of Keller et al., 1987 (Global distribution of late Palaeogene hiatuses. Geology 15, 199–203) and resulted in marine palaeokarstification. The carbonate shelf with the infillings drowned at 34.6 Ma. The caymanites accumulated at about 35.2–35.0 Ma and represent short-term palaeokarstic events. Their deposition record was estimated in several thousand years.  相似文献   

8.
Fossil smicripid beetles are very rare. Here we describe and figure the first Mesozoic representative of Smicripidae. Smicrips cretacea sp. nov., a new species belonging to the extant Smicrips LeConte is preserved in the Upper Cretaceous amber from northern Myanmar. Our discovery suggests that Smicrips is an ancient group, originating at least in the earliest Late Cretaceous. Together with other two fossil Smicrips species from the Eocene of Europe, it reinforces the hypothesis that the Recent distribution of Smicripidae is relict, and the family was more widespread in the Mesozoic and early Cenozoic than it is in the Recent.  相似文献   

9.
李杰  徐钰林 《现代地质》1998,12(3):336-343,T002
研究了菲律宾海盆东北部“大洋钻探工程”125航次782A孔晚始新世以来的放射虫化石。根据Sanfilippo等1985年的分带,将研究区自下而上划分为10个带。讨论了始新世与渐新世、渐新世与中新世、中中新世与晚中新世、中新世与上新世以及上新世与第四纪的界线。研究区存在两个沉积间断,分别位于晚渐新世与早中新世晚期之间和中中新世与晚中新世之间。研究区第四纪放射虫化石仍以暖水分子为主,冷水分子分布较浅。依据放射虫化石分异度曲线得出,晚第三纪以来本区存在5个相对暖水期和5个相对较凉期,渐新世时处于冷水期,这与钙质超微化石复合分异度和碳酸钙含量曲线的变化是一致的。晚渐新世与早中新世晚期之间的沉积间断是由于中新世南极冰盖扩展造成大洋底层洋流活动加剧而形成的。  相似文献   

10.
A new polypore fungus beetle is described and illustrated, under the name of Thescelostrophus cretaceus gen. et sp. nov., representing the first documented occurrence of the tribe Eustrophini. The well-preserved specimen was collected from the Upper Cretaceous (Cenomanian, ca. 99 Ma) amber near the Hukawng Valley of northern Myanmar. This fossil species can be assigned to the extant subfamily Eustrophinae based on its elongate oval and strongly narrowed posteriorly body, simple and narrow tarsi, and somewhat clubbed antennomeres. The comparison among the extinct and extant eustrophines supports the previous hypothesis that antennal morphology of early eustrophines was very diverse. Additionally, an overall similarity between Thescelostrophus and extant eustrophines suggests a potential fungivory of this fossil species. Morphological characters preserved in the Burmese amber highlight the diversity of tetratomids during the Late Mesozoic and provide data for future phylogenetic studies of Tetratomidae.  相似文献   

11.
The ages obtained from planktonic foraminiferal assemblages retrieved from two exposures in the Gurnigel Flysch and from the re-examination of similar material gathered by previous researchers from the Voirons Flysch reveal only minor discrepancies with previous studies based on nannofossil biostratigraphy. In contrast, major divergences between this work and previous studies on the Voirons Flysch also based on planktonic foraminifera have been identified. They are generally related to distinct approaches in species classification and the use of different zonal schemes. Based on our data, the age of the Voirons Flysch extends from the Early Eocene (planktonic foraminiferal zone P7) to the Middle Eocene (planktonic foraminiferal zone P12). Contrasting with claims made in earlier studies, no specimen of Late Eocene or Early Oligocene age has been observed in the revised material. However, we cannot exclude a younger age (possibly Late Eocene) for the upper portion of this flysch from which we did not revise any sample. Thus, more research and sampling are needed to resolve this question. The palaeogeographic origin of the Voirons-Wägital complex as well as the sedimentation history of these flyschs need now to be re-evaluated in light of this revised biostratigraphic data.  相似文献   

12.
依据丰富翔实的地层古生物资料,首次在内蒙古西部建立了比较完整的第三纪地层层序:命名或厘订了中始新统乌兰乌珠尔组、上始新统查干布拉格组、下渐新统乌兰塔塔尔组、上渐新统、下中新统乌尔图组、上中新统呼和好来组和上新统昂冈浩特组等7个地层单元;区分出了中始新世乌兰乌珠尔、晚始新世查干布拉格、早渐新世早期克克阿木、早渐新世晚期乌兰塔塔尔、晚渐新世因德里沟、早中新世乌尔图、晚中新世呼和好来和上新世昂冈浩特等8个动物群(组合)。  相似文献   

13.
Sclerorhynchiform sawfishes are a diverse and extinct clade of elasmobranchs that is restricted to the Cretaceous. Most taxa are known only by isolated rostral spines, whereas skeletal remains are rare and have been reported from a small number of Upper Cretaceous localities. Here, we describe skeletal remains of the giant sclerorhynchiform Onchosaurus pharao for the first time, which provides new morphological information. The single specimen comes from middle-basal upper Turonian strata of the Lessini Mountains in northeastern Italy and represents the first record of this genus from Italy. The specimen consists of unidentifiable cranial remains, several diagnostic rostral spines, the rostrum with fragments of tessellated calcified cartilage, and 87 disarticulated vertebrae. The rostrum preserves the characteristic sensory system of sclerorhynchiforms. It is devoid of any lateral sockets indicating that rostral spines were attached laterally to its surface. This pattern is identical to most sclerorhynchiforms and extant pristiophoriformes implying also similar replacement patterns as in most other sclerorhynchiforms with the exception for Schizorhiza. Additionally, the bases of two longitudinally arranged rows of ventral rostral spines are identifiable concurring with patterns seen in Sclerorhynchus. The axial skeleton is partly preserved. Re-arranging the disarticulated vertebrae according to their life position in combination with measures of the size and thickness of preserved vertebral centra, and the ratio rostrum length/body size depending on the number of vertebral centra indicate that the specimen was ca. 450 cm long. Growth rings in the vertebral centra show that the specimen was about four years old and thus probably not yet fully sexual mature when it died. This age assumption corresponds well with the calculated size when compared with complete skeletons of extinct sclerorhynchiforms and extant pristiforms. The size of the specimen and its occurrence in hemipelagic rocks corroborates previous assumptions that this sclerorhynchiform was a large and pelagic sawfish.  相似文献   

14.
Diverse new material of mantises found in the Cretaceous amber-bearing deposits from Lebanon (Barremian), Spain (Albian), and Myanmar (Albian–Cenomanian) are described and figured. The Lebanese and Spanish forms are nymphs; while the one from Myanmar is an adult specimen. The Lebanese nymph corresponds to a new specimen of Burmantis lebanensis Grimaldi, 2003 while the adult Burmese (Myanmar) specimen belongs to the new species Burmantis zherikhini. The Spanish specimen represents a new genus and species and is established as Aragonimantis aenigma, but is considered family incertae sedis. The Spanish specimen is the first record of Mesozoic mantises from western-European amber deposits. A revised phylogenetic hypothesis for Cretaceous mantises is proposed.  相似文献   

15.
The External Tanger Unit represents one of the most complete Cretaceous-Miocene successions in the central areas of the Internal Intrarif sub-Domain (External Rif Zones, Morocco). An interdisciplinary study has been carried out to propose a new characterization of this unit which would allow a better comprehension of the confused and complex relationships among different units of the same sub-domain. The results achieved can be summarized as follows: (1) redefinition of the stratigraphic (litho-, bio-, and chrono-) record and introduction of a new, informal lithostratigraphic terminology; (2) recognition of two main depositional sequences (lower-middle Eocene p.p. and lower Oligocene p.p.-lower Miocene p.p.) separated by extended gaps (latest Cretaceous-early Eocene p.p. and middle Eocene p.p.-early Oligocene p.p.); (3) reconstruction of the evolution of the sedimentary realm, and of the relationships between tectonics and sedimentation; and (4) comparison between the upper Cretaceous-Miocene stratigraphic record and tectonic events of the Intrarif, which is located in the western external portion of the Maghrebian Flysch Basin, and the equivalent sedimentary record of the eastern portion of this basin in the Tunisian Tell. More in general, our results allowed (i) a first reconstruction of the Cretaceous-Miocene main tectono-sedimentary events; (ii) a more detailed location of the sedimentary suite in the external African Margin in the context of a wider palaeogeographic framework; and (iii) the definition of the main stages of the geological evolution of the area.  相似文献   

16.
Nelumbo Adans. (Nelumbonaceae) is an important member of the early-diverging eudicots. It contains two extant species: N. nucifera Gaertn. (the Sacred lotus), distributed in Asia and Australia and N. lutea Willd. (the American lotus), occurring in North America. This paper reviews the taxonomic, evolutionary and phytogeographic studies of the genus Nelumbo, and also raises scientific questions about it in further paleobotanic research. There are about 30 fossil species of Nelumbo established since the Early Cretaceous. Based on fossil studies, the ancestors of the extant N. nucifera and N. lutea are respectively considered to be N. protospeciosa from the Eocene to Miocene of Eurasia, and N. protolutea from the Eocene of North American. However, molecular systematic studies indicate that N. nucifera and N. lutea are probably split from a common ancestor during the Late Miocene to Early Pliocene, or even the Pleistocene, rather than separate relicts from extinct species on different continents. The characters of lotus stomatal development, seedling morphology as well as its flowering, pollination and fertilization in air reveal that it evolves from the land plants. Fossil data of Nelumbo indicates that the genus first occurs in mid-latitude area of Laurasia in the Early Cretaceous, then becomes widespread in North America and Eurasia and expands into Africa and South America during the Late Cretaceous; the genus probably colonizes the Indian Subcontinent from Asia during the Early Eocene after the collision of India and the Asian plates; the genus becomes extinct in Europe, but survives in Asia and North America during the Quaternary Ice Age, and later forms the present East Asia and North Australia-North America disjunctive distribution.  相似文献   

17.
This paper presents palaeontological ages based on new nannofossil and foraminiferal studies from a range of sedimentary rocks from the provinces of West and East Kalimantan, Indonesia. The age of sedimentary rocks in Kalimantan, away from the main hydrocarbon exploration areas of the coastal regions, represents a major gap in our basic knowledge of the island of Borneo. The implications of these new results and existing and new correlations are reviewed and suggested. In particular, the base of the Tertiary section in the Kutai Basin is shown to be upper Middle Eocene in age, rather than Late Eocene as originally thought. The limestones of the Batu Belah member of the Ujoh Bilang Formation are dated as NP24–25, Late Oligocene, rather than Early Oligocene as earlier work had suggested. In the western part of the Mangkalihat Peninsula area the base of the Tertiary section is determined to be Late Oligocene. Various basement units from both East and West Kalimantan contained Late Jurassic to Late Cretaceous microfossils.  相似文献   

18.
We describe two new species of extinct biting midges in the fossil genus Protoculicoides: Protoculicoides hispanicus Szadziewski and Arillo, sp. nov. and Protoculicodes sanjusti Szadziewski and Arillo, sp. nov., from Albian (101–113 Ma) amber of San Just, Spain. Atriculicoides Remm, 1976 is recognized as a new junior synonym of Protoculicoides Boesel, 1937 (NEW SYNONYM). Devalquia Choufani et al., 2013 is regarded here as a new junior synonym of the extant genus Culicoides Latreille, 1809 (NEW SYNONYM). Metahelea roggeroi Choufani et al., 2013 from Upper Cretaceous French amber, is excluded from the tribe Heteromyiini and placed in the extant genus Stilobezzia Kieffer, 1911, tribe Ceratopogonini: Stilobezzia roggeroi (Choufani et al., 2013), comb. nov. The extinct tribe Atriculicoidini Szadziewski, 1996 is regarded as a new subfamily, Atriculicoidinae, stat. nov., that includes the fossil genus Protoculicoides, with 13 species reported from Albian, Turonian, Cenomanian, Coniacian, Santonian and Campanian ambers (78–113 Ma). Protoculicoides skalskii Szadziewski & Arillo, 1998 from Lower Cretaceous amber of Álava, Spain, Protoculicoides succineus Szadziewski, 1966 from Lower Cretaceous Lebanese amber and Protoculicoides burmiticus Szadziewski & Poinar, 2005 from Upper Cretaceous Burmese amber are transferred to the extinct genus Archiculicoides Szadziewski, 1996, comb. nov. Protoculicoides krzeminskii Choufani et al., 2014 from Lower Cretaceous Lebanese amber is transferred to the extinct genus Archiaustroconops Szadziewski, 1996, comb. nov. The Cretaceous subfamily Atriculicoidinae forms an unresolved trichotomy with the extant subfamilies Forcipomyiinae and Dasyheleinae, both of which date to the Eocene. The fossil record indicates that wings with macrotrichia in biting midges evolved during the mid-Cretaceous greenhouse climate. We suggest that this was an evolutionary adaptation to new atmospheric conditions with higher levels of CO2 in order for the antennal Johnston's organs of males to receive the vibrational sex signals produced by females during flight.  相似文献   

19.
Earwigs (Dermaptera) are scarce in the fossil record. Over a hundred fossil dermapterans have been described to date, the oldest undisputed fossils dating back to the Late Triassic. Here, two new species, Phanerogramma kellyi sp. nov. and Brevicula teres sp. nov., are described from the Rhaetian and Sinemurian of England, respectively, from isolated tegmina. The features that distinguish fossil earwig fragments from other insect remains are discussed. A catalogue of fossil and subfossil Dermaptera is appended.  相似文献   

20.
采自云南泸西县城附近小兴安村晚三叠世卡尼期小凹组的海龙化石,是关岭生物群海龙类化石在贵州关岭之外地区的首次发现。该化石标本共保存有9枚较好的背椎骨,21条完好的肋骨及若干腹肋。靠近头部的4枚背椎骨为有次序的自然排列。背椎椎体长约12cm,椎体横突发育,椎体腹侧轻微凹入,呈双凹形,近似圆形。这一特征与鱼龙类脊椎骨明显的双凹特征有所区别,故暂且将其归于海龙类。新采集的该化石标本为探讨海龙类的古地理分布,以及寻找规律生物群新化石产地提供了信息。  相似文献   

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