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1.
Fossil remains of beetles are described from two Lower Triassic localities: Entala (Induan) and Tikhvinskoe (Olenekian). Only one beetle fossil was previously known from the Lower Triassic of Tikhvinskoe. The fossils are rather few and poorly preserved, but they are worth describing as finds rare for the Lower Triassic. Five fossils from Entala most probably belong to beetles of the same species of the formal genus Pseudochrysomelites. Beetles of this genus are especially abundant in deposits close to the Permian–Triassic boundary and can be considered “disaster taxa.” There are no known cases, either in the Permian or in the Middle–Upper Triassic, of a random sample of five specimens belonging to a single species. This suggests that in the Entala oryctocenosis the species diversity of beetles is extremely low. All three beetle fossils found in Tikhvinskoe belong to beetles of different species, showing that diversity had already started to increase. However, it remained low, and all fossils belong to the formal family Schizocoleidae, and two of the three belong to the same genus, Pseudochrysomelites. The Khei-Yaga locality, which immediately follows Tikhvinskoe in time (topmost Olenekian or early Anisian), already contains beetles of the families Asiocoleidae and Permosynidae. In the Lower Anisian of the Buntsandstein, such typical Mesozoic beetles as Cupedidae and Coptoclavidae have been recorded. The appearance of such advanced beetles as early as the Lower Anisian suggests that the famous Permian–Triassic crisis was not as deep as it is usually believed, and many beetles survived it, disappearing, however, from the fossil record in the Early Triassic.  相似文献   

2.
Zoophycos is a well-known trace fossil common throughout the Phanerozoic. Paleozoic forms show important differences in morphology and habitat distribution with respect to the Jurassic, Cretaceous, and Cenozoic ones. Therefore, Early–Middle Triassic is considered a crucial time-span for the understanding of the evolution of this trace fossil. So far, Early Triassic Zoophycos is unknown and Middle Triassic forms were recorded only in deposits from Thuringia. The morphology and paleoenvironment of Zoophycos from the middle–upper Muschelkalk of the Iberian Range is herein described. The best-preserved trace fossils occur in a dolomicritic bed Ladinian in age, and are represented by small forms with a subcircular, slightly lobed outline and very little penetration depth. They were deposited in a very shallow, quiet-water environment with transition to supratidal/emerged areas. The low diversity of both trace fossils and skeletal remains point to stressful conditions related to strong salinity variations and/or poor water circulation. A comparison was made with Zoophycos from Anisian deposits of the Muschelkalk in Germany. This showed that both forms are quite simple and penetrate only the shallowest tiers, although they are different in whorl outline and lobe shape. This confirms that, notwithstanding the morphological variability of this group, Zoophycos still maintained a quite simple structure in the Triassic. A shallow-water environment was deduced for both localities, confirming that at least until the Early Jurassic Zoophycos had not definitively migrated toward deep-water areas.  相似文献   

3.
The Palaeozoic–Mesozoic transition is characterized not only by the most massive Phanerozoic mass extinction at the end of the Permian period, but also its extensive aftermath and a prolonged period of major biotal recovery during the succeeding Middle to Late Triassic. Particularly, Anisian insect species from units of the Lower to Middle Muschelkalk from the Central European Basin are rare. The specimens described here originated from the Anisian Wellenkalk facies (Lower Muschelkalk), Vossenveld Formation of the Winterswijk quarry, The Netherlands, and from the orbicularis Member (lowermost Middle Muschelkalk, Anisian) of Esperstedt near Querfurt (Saxony-Anhalt). Thus, the described insect remains from Winterwijk and Esperstedt expand our knowledge about Middle Triassic terrestrial arthropod communities and their palaeodiversity. A new species of Chauliodites (C. esperstedti sp. nov) is introduced.  相似文献   

4.
预言鱼目是近鲱形类的一个绝灭支系,被认为是弓鳍鱼目的姐妹群.预言鱼目化石过去主要发现于欧洲的中三叠世拉丁期和晚侏罗世地层以及新大陆的早白垩世地层.近年来,在云南和贵州的中三叠世安尼期地层中分别发现了一种预言鱼目鱼类化石(强壮鱼和盘县鱼),代表了该目在中国的首次发现.根据产于云南罗平中三叠世安尼期(~244 Ma)海相地层中的6块保存良好的鱼化石,命名了预言鱼目一个新的属种,三叠复兴鱼(Subortichthys triassicus gen.et sp.nov.).三叠复兴鱼是罗平生物群中发现的第二种预言鱼目鱼类,代表了预言鱼目最古老的化石记录之一,为研究该目的起源和早期分异提供了重要信息.复兴鱼无疑可以归入近鲱形类,因为它具有近鲱形类两个共近裔性状,续骨与下颌关节以及上颌骨后缘具有凹缺.分支分析结果表明,复兴鱼位于预言鱼目的基部,因为它具有该目的重要鉴定特征,上颌骨具有感觉管,但它不具有其他预言鱼目鱼类的进步特征.特别的是,复兴鱼具有一些独特的性状,如额外肩胛骨3或4对、第三眶下骨特别宽大并与前鳃盖骨前缘相接等.复兴鱼的发现表明预言鱼目鱼类在华南地区(三叠纪时期位于古特提斯洋的东部)的早期分异至少发生在中三叠世早期(安尼期).  相似文献   

5.
The ascent of dinosaurs in the Triassic is an exemplary evolutionary radiation, but the earliest phase of dinosaur history remains poorly understood. Body fossils of close dinosaur relatives are rare, but indicate that the dinosaur stem lineage (Dinosauromorpha) originated by the latest Anisian (ca 242-244 Ma). Here, we report footprints from the Early-Middle Triassic of Poland, stratigraphically well constrained and identified using a conservative synapomorphy-based approach, which shifts the origin of the dinosaur stem lineage back to the Early Olenekian (ca 249-251 Ma), approximately 5-9 Myr earlier than indicated by body fossils, earlier than demonstrated by previous footprint records, and just a few million years after the Permian/Triassic mass extinction (252.3 Ma). Dinosauromorph tracks are rare in all Polish assemblages, suggesting that these animals were minor faunal components. The oldest tracks are quadrupedal, a morphology uncommon among the earliest dinosauromorph body fossils, but bipedality and moderately large body size had arisen by the Early Anisian (ca 246 Ma). Integrating trace fossils and body fossils demonstrates that the rise of dinosaurs was a drawn-out affair, perhaps initiated during recovery from the Permo-Triassic extinction.  相似文献   

6.
The first Mesozoic representative of the extinct archostematan beetle family Permocupedidae, Frankencupes ultimus, gen. et sp. nov., is described based on two isolated elytra from the Lower Anisian (Middle Triassic) Röt Formation of Lower Franconia, Germany. The new fossil occurrence extends the range of the family from the Lower Wuchiapingian (Upper Permian) up to the Anisian, and represents a fine example of a Lazarus taxon in the fossil record of beetles.  相似文献   

7.
To discern the effect of the end-Permian (P-Tr) ecological crisis on land, interactions between plants and their insect herbivores were examined for four time intervals containing ten major floras from the Dolomites of northeastern Italy during a Permian–Triassic interval. These floras are: (i) the Kungurian Tregiovo Flora; (ii) the Wuchiapingian Bletterbach Flora; (iii) three Anisian floras; and (iv) five Ladinian floras. Derived plant–insect interactional data is based on 4242 plant specimens (1995 Permian, 2247 Triassic) allocated to 86 fossil taxa (32 Permian, 56 Triassic), representing lycophytes, sphenophytes, pteridophytes, pteridosperms, ginkgophytes, cycadophytes and coniferophytes from 37 million-year interval (23 m.yr. Permian, 14 m.yr. Triassic). Major Kungurian herbivorized plants were unaffiliated taxa and pteridosperms; later during the Wuchiapingian cycadophytes were predominantly consumed. For the Anisian, pteridosperms and cycadophytes were preferentially consumed, and subordinately pteridophytes, lycophytes and conifers. Ladinian herbivores overwhelming targeted pteridosperms and subordinately cycadophytes and conifers. Throughout the interval the percentage of insect-damaged leaves in bulk floras, as a proportion of total leaves examined, varied from 3.6% for the Kungurian (N = 464 leaves), 1.95% for the Wuchiapingian (N = 1531), 11.65% for the pooled Anisian (N = 1324), to 10.72% for the pooled Ladinian (N = 923), documenting an overall herbivory rise. The percentage of generalized consumption, equivalent to external foliage feeding, consistently exceeded the level of specialized consumption from internal feeding. Generalized damage ranged from 73.6% (Kungurian) of all feeding damage, to 79% (Wuchiapingian), 65.5% (pooled Anisian) and 73.2% (pooled Ladinian). Generalized-to-specialized ratios show minimal change through the interval, although herbivore component community structure (herbivore species feeding on a single plant-host species) increasingly was partitioned from Wuchiapingian to Ladinian. The Paleozoic plant with the richest herbivore component community, the coniferophyte Pseudovoltzia liebeana, harbored four damage types (DTs), whereas its Triassic parallel, the pteridosperm Scytophyllum bergeri housed 11 DTs, almost four times that of P. liebeana. Although generalized DTs of P. liebeana were similar to S. bergeri, there was expansion of Triassic specialized feeding types, including leaf mining. Permian–Triassic generalized herbivory remained relatively constant, but specialized herbivores more finely partitioned plant-host tissues via new feeding modes, especially in the Anisian. Insect-damaged leaf percentages for Dolomites Kungurian and Wuchiapingian floras were similar to those of lower Permian, north-central Texas, but only one-third that of southeastern Brazil. Global herbivore patterns for Early Triassic plant–insect interactions remain unknown.  相似文献   

8.
Biodiversity and biogeographic studies comparing the distribution patterns of benthic marine organisms across the Iberian Atlantic and Mediterranean waters are scarce. The Pycnogonida (sea spiders) are a clear example of both endemicity and diversity, and are considered a key taxon to study and monitor biogeographic and biodiversity patterns. This is the first review that compiles data about abundance and diversity of Iberian pycnogonids and examines their biogeographic patterns and bathymetric constraints using GIS tools. A total of 17762 pycnogonid records from 343 localities were analyzed and were found to contain 65 species, 21 genera and 12 families. Achelia echinata and Ammothella longipes (family Acheliidae) were the most abundant comprising ~80% of the total records. The Acheliidae is also the most speciose in Iberian waters with 15 species. In contrast, the family Nymphonidae has 7 species but is significantly less abundant (<1% of the total records) than Acheliidae. Species accumulation curves indicate that further sampling would increase the number of Iberian species records. Current sampling effort suggests that the pycnogonid fauna of the Mediterranean region may be richer than that of the Atlantic. The Strait of Gibraltar and the Alboran Sea are recognized as species-rich areas that act as buffer zones between the Atlantic and Mediterranean boundaries. The deep waters surrounding the Iberian Peninsula are poorly surveyed, with only 15% of the sampling sites located below 1000 m. Further deep-water sampling is needed mainly on the Iberian Mediterranean side.  相似文献   

9.
A subrosion pipe or sinkhole is a geologic phenomenon that occurs due to dissolution of strata in the subsurface causing the overlying sediments to collapse. The subrosion pipe in the Winterswijk quarry complex in the eastern Netherlands yielded rare, dark-colored shales. Bivalves and palynomorphs indicate that the shales were deposited during the Rhaetian (uppermost Triassic). In addition, detailed correlation with other NW European localities in Great Britain, Austria, and Germany further constrained the age of the shales to the middle of the Rhaetian. The shales were deposited in a near-coastal environment and contained a low diverse macroinvertebrate fauna with bivalves and some brittle stars that lived in a hostile environment, probably caused by low salinity and oxygen levels. These middle Rhaetian shales were mixed with dark-colored middle to late Hettangian sediments, both overlying Middle Triassic (Anisian) strata, which is present in the pipe as well. The presence of Rhaetian sediments in the subrosion pipe reopened the discussion on its age of formation. We suggest that a collapse in the Middle Eocene is most likely. This research expands the knowledge of the marine realms in the uppermost Triassic in Europe, just prior to the Permian–Triassic extinction event.  相似文献   

10.
The Mesozoic sedimentary cover belonging to the Monte Carmo-Rialto unit of the Ligurian Briançonnais domain is composed of Scythian clastics and Anisian to Carnian carbonate rocks over 300 m thick. This paper focuses on the stratigraphy of this carbonate complex, its environmental significance, and its evolution in light of dynamic stratigraphy. Our facies analysis of limestones and dolomites of the Triassic complex allowed us to reconstruct an environmental model. Data support a distally steepened carbonate ramp of Anisian age evolving to a more diversified Ladinian platform with an oolitic sand-bar belt separating the lagoon from the slope. The Monte Carmo-Rialto slope facies are the only witnesses of deep sedimentation in the Triassic terrains of the Ligurian Briançonnais domain, otherwise represented by shallow-water carbonate deposits. On the basis of facies succession, we have identified nine medium-scale cycles (third-order sequences) in the study area, comparable to those evidenced in the Briançonnais s.s. domain by the French authors. Small-scale cycles analysis evidenced mainly shallowing-upward trends in the examined sequences; although a few evidences of transgression-related deposits (deepening upward cycles) have been found at the base three sequences, they have been mostly obliterated by dolomitization and masked by local tectonics. For this reason, we can undoubtedly distinguish only the part of each sequence belonging to HST, while the TST, though present, still remains a partition that cannot be precisely characterized. In the same way, LSTs are not present in the Monte Carmo-Rialto unit, due to the original relative landward position of the examined area. Sequence stratigraphy analysis indicates different long-term dynamics for the two evolutionary stages of the Triassic Ligurian platform: a general landward backstepping to moderate progradation during the Early Anisian and true progradation during the latest Anisian and Ladinian. In addition, a good fit with the sequences proposed by the SEPM chart has been found, indicating a correspondence for the third-order sequences of the Middle Triassic.  相似文献   

11.
川东北及陕南三叠纪有孔虫   总被引:2,自引:0,他引:2  
何炎 《古生物学报》1993,32(2):170-187
四川宣汉、万源、旺苍及陕西镇巴三叠纪有孔虫产于中统雷口坡组,下统嘉陵江组及飞仙关组上部.根据有孔虫的分布,划分下统为两个带,5个亚带,中统1个带,并讨论了其对比问题.  相似文献   

12.
广西凤山、西林等地中三叠统上部双壳类分带研究*   总被引:7,自引:3,他引:4  
讨论广西西部中三叠统上部的双壳类生物地层序列,建立5个化石带;并附述黔南和滇东南晚三叠世1个双壳类带.这些带自下而上为:(1) Daonella (Longidaonella) producta-D. americana 带,属晚安尼早中期;(2) D. moussoni 高峰带,属晚安尼晚期;(3) D. rieberi-D. indica 带,属早拉丁期;(4) D. kotoi-D. jilongensis 带,属晚拉丁早期;(5) Halobia subcomata-D. varifurcata带,属晚拉丁晚期;(6) H. rugosoides-H. bifurcata 带,属早卡尼期.文内简要描述了各带的主要标志化石23种.  相似文献   

13.
14.
Echinoid remains from the Triassic of China are described for the first time. The Middle Triassic of Qingyan in Guizhou Province, south-western China, has yielded nine taxa of primary spines; seven of these come from the lower Upper Anisian. Because all of the spines are disarticulated, the material is treated only parataxonomically. 'Cidaris' lineola (Bather) and 'Cidaris' wissmanni (Desor) are species originally described from the alpine Triassic of Europe. 'Cidaris' bangtoupoensis sp. nov., 'Cidaris' wachangpoensis sp. nov., 'Cidaris' venustespinosa sp. nov., 'Cidaris' fangchui sp. nov., 'Cidaris' gu sp. nov., 'Cidaris' mafengpoensis sp. nov. and 'Cidaris' sp. A are so far known only from Qingyan. Palaeoautecological interpretations based on the shapes of the spines fit well with the fact that the echinoids from Qingyan are part of highly diverse fossil associations which represent the remains of communities that lived in a protected, shallow-marine, stable soft-bottom habitat. The rather high diversity of the echinoid spines in terms of the number of both taxa and general types of shape shows that the echinoids, after nearly becoming extinct at the end of the Palaeozoic, began a new phase of adaptive radiation in the Anisian at the latest.  相似文献   

15.
Abstract:  Three new genera including four new species of the bivalve family Mysidiellidae are described from late middle to early late Anisian (Middle Triassic) deposits of Qingyan, Guizhou Province, south-west China. The new taxa Leidapoconcha gigantea gen. et sp. nov., Waijiaoella elegans gen. et sp. nov., Waijiaoella speciosa gen. et sp. nov. and Qingyaniola mirabilis gen. et sp. nov. significantly increase the known taxonomic diversity within the Mysidiellidae. These findings suggest a somewhat endemic evolutionary development within this small bivalve family during the Middle Triassic in south-west China.  相似文献   

16.
Abstract:  Well-preserved floras from the Alpine Early–Middle Triassic are rare, and thus our understanding of the vegetation in this area during this period of time continues to be incomplete. As a result, every new find represents a significant piece of information that deserves thoughtful consideration. Anisian (Middle Triassic) sphenophytes and pteridosperms have recently been recovered from the Kühwiesenkopf locality (Monte Prà della Vacca) in northern Italy. The sphenophytes are represented by stem fragments, strobili and isolated sporangiophore heads of Equisetites , as well as by a few specimens of Neocalamites sp. and Echinostachys sp. The pteridosperms include abundant remains of the peltasperm foliage type Scytophyllum bergeri . A second Scytophyllum species in this flora, S. apoldense , is regarded as conspecific with S. bergeri based on epidermal anatomy; the two morphotypes are interpreted as sun and shade leaves of a single biological species. The seed-bearing disc Peltaspermum bornemannii sp. nov. probably represents the female reproductive structure of S. bergeri . Additional pteridosperm remains include foliage assignable to Sagenopteris sp. and Ptilozamites sp., in both cases perhaps the earliest records of these genera.  相似文献   

17.
《Palaeoworld》2022,31(3):428-442
The Himalaya Terrane of southern Tibet exposes successive shallow-marine carbonate deposits from the Lower to Upper Triassic, and is a key region for studying the Triassic conodont biostratigraphy at the northern margin of the Indian Plate. On the basis of newly collected samples from the Kangshare and Laibuxi formations at the Tulong section, 11 conodont species of 7 genera were identified, and four conodont zones were established, namely, the Novispathodus abruptus Zone (lower Spathian, first reported in Tibet), the Columbitella jubata Zone (middle Spathian), the Triassospathodus symmetricus Zone (upper Spathian), and the Chiosella timorensis Zone (lowermost Anisian) in ascending order. The first occurrence (FO) of Chiosella timorensis indicates the Olenekian–Anisian boundary (OAB) at Bed 25, upper part of the Kangshare Formation. The regional and global correlation of these conodont zones is synthesized.  相似文献   

18.
19.
In this paper, we examine the diversity trends and the evolutionary patterns of Triassic conodonts through a newly powered large-scale data-set compiled directly from the primary literature. Paleodiversity dynamics analyses have been undertaken by working at the species level and using a system of time units based on biozone subdivisions for a fine temporal level resolution. The role of heterogeneous duration of taxa in diversity estimates has been evaluated through the probabilistic profiles. Results reveal three different stages in the diversity behaviour of Triassic conodonts from standing metrics delimited by two inflections at the mid-Anisian and mid-Carnian. Survivorship analysis supports this pattern. Origination–extinction metrics report a diversification pattern characterised by important fluctuations during the Lopingian–Induan (earliest Triassic), the early-middle Olenekian (Early Triassic) and the Anisian–Ladinian transitions (Middle Triassic), as well as in the early Late Triassic. In addition, two clear diversification peaks are observed in the late Carnian and in the end-Norian. Reported patterns are interpreted in the context of deep extinction and environmental instability by documenting the biological signal of the main diversification and turnover patterns observed from such records. This study emphasises the singularity behaviour of diversity trends derived from the conodont record.  相似文献   

20.
Records of plant megafossils in the Devonian of the Iberian Peninsula refer to sparse drifted remains in marine strata, apart from unidentifiable debris, and misidentified ichnofossils. The age attributions are sometimes questionable. A critical analysis leaves only five localities with incidental Devonian plant megafossils capable of sustaining approximate taxonomic identifications. Another two localities of possible late Devonian age are more likely earliest Carboniferous. The various records are discussed in their geological context, taking into account that the Iberian Massif was constituted from different terranes in Pennsylvanian times. A critical discussion is presented of the reviews published by Montero (2008) and Montero and Diéguez (2010), particularly the latter which adds considerations on floral composition and sedimentary environments which lack a factual basis. A later paper by Cascales-Miñana et al. (2011) is commented on.  相似文献   

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