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1.
A new genus and species of tetrablemmid spider, Electroblemma bifida n. gen. et sp., is described, from two adult males found in Upper Cretaceous (Cenomanian) amber of Myanmar. The genus is distinguished by its enormous dorsal carapace projection and highly modified chelicerae. The new genus is referred to the tribe Tetrablemmini within the subfamily Tetrablemminae. The presence of a relatively derived tetrablemmid on the south-east Eurasian continent during the Late Cretaceous suggests that the family was already well diversified in tropical rainforests at this time.  相似文献   

2.
The calcareous nannofossil genus Eiffellithus is an important taxon of mid- to Upper Cretaceous marine sediments in biostratigraphy and paleoceanography. The definition of species within Eiffellithus have been both broadly interpreted and variably applied by nannofossil workers. This is particularly true for the Eiffellithus eximius plexus. While the taxonomy of mid-Cretaceous Eiffellithus species has recently been well-defined, the remaining 35 m.y. history of the genus has not been closely examined. Our investigation of Cenomanian to Maastrichtian sediments from the Western Interior Seaway, Gulf of Mexico, and Western Atlantic gives rise to six new species of Eiffellithus that can be reliably differentiated. In this paper the hitherto used biostratigraphic markers (E. turriseiffelii and E. eximius) have been redefined in a more restricted sense to increase their utility. These refinements in taxonomy reveal an obvious shift in abundance both within the genus and within the nannofossil assemblage as a whole through the Late Cretaceous. In the Cenomanian and Maastrichtian the genus is composed exclusively of coccoliths bearing an X-shaped central cross, such as E. turriseiffelii, while in the Coniacian through Campanian axial-cross forms such as E. eximius comprise more than 60% of the genus. Within the nannofossil assemblage the genus has low abundances in the Cenomanian but increases to >15% of the assemblage in well-preserved samples in the Santonian. In addition, the pattern of diversification of this genus, whereby a x-shaped, diagonal cross repeatedly gives rise to an axial cross by rotation about the central axis, is an excellent example of iterative evolution that may be related to repetitive shifts in Late Cretaceous climatic and paleoceanographic regimes.  相似文献   

3.
The Permian section situated northwest of Tabas in the Halvan Mountains is studied and fusulinids occurring in the section are described. The Chili, Sartakht, and Hermez formations distinguished in the section are separated by horizons of bauxitic laterite and belong to the Khan Group formerly ranked as a synonymous formation. Fusulinids occur at two levels in the section. The lower one confined to the Chili Formation yields the so-called Kalaktash fusulinid assemblage of the late Sakmarian age. The second late Asselian assemblage has been discovered in pebbles from conglomerate-breccia in the basal laterite of the Sartakht Formation. A brief characterization of fusulinids is presented and three new species are described. The new Benshiella genus is discriminated from the Rugosofusulinidae family. As Skinner and Wilde (1965, 1966) changed the original diagnosis of the Pseudofusulina genus, we suggest, regarding all species, which have been attributed to this genus but do not satisfy the new diagnosis, as representing the new Nonpseudofusulina genus.  相似文献   

4.
The paper discusses the evolution of Stromatoporoidea in the epicontinental sedimentary basin of the Siberian Platform and Taimyr during the Ordovician and Silurian. Specimens of the oldest genus, Priscastroma, were found in the middle of Middle Ordovician sediments. This genus is represented by the species P. gemina Khrom., which has two forms, A and B. Tracing the emergence of new genera over time, we identified two distinct branches in stromatoporoid evolution.The ancestor of the first branch is P. gemina f. A, which gave rise to the genus Cystostroma. The latter is the ancestor of two subbranches with predominant horizontal skeletal elements. The subbranches differ only in tissue microstructure. The genera Stromatocerium, Dermatostroma, and Aulacera display dense fibrous microstructure, whereas the genus Rosenella and its descendants display dense microstructure. The genus Lophiostroma, with a lamellar–fibrous tissue, may be a dead branch of evolution.The ancestor of the second branch is P. gemina f. B, which gave rise to the genus Labechia and its descendants. This branch has a dense tissue, with predominant vertical skeletal elements.Ordovician stromatoporoids from Siberia were compared with those from other basins of the world. Comparison shows that all the Ordovician genera from the epicontinental basin of the Siberian Platform and Taimyr originated here. Thus, this basin was one of the centers of stromatoporoid origin.  相似文献   

5.
A new genus and species of earwig is described and figured from Early Cretaceous (Latest Albian-Earliest Cenomanian) amber of southwestern France. The holotype was studied using traditional light microscopy as well as through propagation phase contrast X-ray synchrotron microtomography, rendering high resolution three-dimensional models for critical examination. Gallinympha walleri Perrichot & Engel, new genus and species, is represented by two late instar nymphs missing only portions of the abdomen, as well as most of the head for the paratype. The genus is a member of the Pygidicranidae, one of the most basal of living earwigs, and is distinguished from other taxa in the family. A thorough account of the specimen’s morphology is provided along with a detailed comparison with similar structures across a diversity of primitive earwig lineages.  相似文献   

6.
Novelaria, a new genus of rhagionid of late Albian age with three new species, is the first record of this family from Charentes amber (southwestern France). The new genus is probably closely related to the recent genus Chrysopilus. However its relationship with the other fossils in amber is discussed. A key for separation of the new species is provided and the diversity of the family during the Cretaceous is also briefly discussed.  相似文献   

7.
In 2007, Reguero et al. described a 2.5 Ma erethizontid dentary from the Uquía Formation in Argentina (MACN5376) and referred it to the genus Erethizon, a genus found at present only in North America. They based their generic identification on the presence in the fossil of a markedly inflected angular process. I argue in this commentary that this single trait (the angular process) in a single incomplete fossil is insufficient evidence for the Erethizon attribution, for the following reasons: 1. The trait (the inflected angular process) is variable in modern South and North American porcupines and observer bias and/or allometry may be responsible for observed differences; 2. Among fossil South American porcupines, the inflected angular process is not unique to the Uquían fossil; 3. The fossil possesses other traits (including one trait newly described in this paper) associated with modern South American (Coendou) porcupines and not modern Erethizon; and 4. The traits by which we recognize modern Erethizon, primarily related to the genus’s ability to survive severe winters, are most readily explained by evolution driven by the South American porcupine immigrants’ exposure in North America to that severe weather. The Uquían fossil is not Erethizon and should be attributed for the present to the genus Coendou.  相似文献   

8.
A new species of the clupeid genus Scombroclupea is described from the Upper Cretaceous (Cenomanian) Plattenkalk locality “Loma la Mula” in Coahuila, northeastern Mexico. The material provides new osteological data for the genus, which clarify its systematic position. The Mexican Scombroclupea points to an occurrence of the genus in the western Tethys and indicates a vicariant event between S. macrophthalma from Lebanon and Croatia and the new species described herein. The analysis of the functional morphology of Scombroclupea supports the reconstruction of an oscillatory locomotion mode in this genus.  相似文献   

9.
Helius ewa sp. nov., one of the oldest representative of the genus Helius Lepeletier and Serville 1828 (Diptera: Limoniidae) from the Lebanese amber (Lower Cretaceous) is characterized, illustrated and described. The evidences of rapid evolution of the genus Helius are provided. The hypothesis on the origin of the evolution of this genus in Gondwana and the possibility of rapid radiation and expansion in Laurasia are discussed. A complete list of Cretaceous limoniids belonging to Helius is given.  相似文献   

10.
A new species of the extinct ant genus Baikuris Dlussky, 1987 (Formicidae: Sphecomyrminae) is described and figured from a male preserved in a piece of ∼100 Myr amber from Charentes, in southwestern France. Baikuris maximus sp. nov., is distinguished from other species notably by its larger size, its forewing with vein 2M+Cu absent and vein 3Cu tubular, and the presence of a subpetiolar process. The diagnosis of the genus is emended, and its distribution during the Cretaceous is briefly discussed.  相似文献   

11.
The monotypic genus Pseudalces Flerov 1962 (Mammalia: Cervidae), containing P. mirandus Flerov 1962 from the middle Pliocene near Stavropol, is described on the basis of few cranial fragments including two partial upper tooth rows. The genus is distinguished from other cervids by its elongated muzzle and lachrymal, its tapering forehead, its antler pedicle orientation and other features.—C. E. Ray  相似文献   

12.
A new fossil soldier beetle Myamalycocerus vitalii gen. et sp. nov., is described and illustrated from an inclusion in Upper Cretaceous Burmese amber (Myanmar). It differs from all extant genera that have elytra adorned with small striae by possessing raised punctation, very probably an ancient character as it is absent among current species. It differs from the fossil Ornatomalthinus Poinar et Fanti, by the long elytra and relief points which are less raised and more numerous. This new genus appears vaguely related (not necessarily phylogenetically) to the current genus Lycocerus Gorham.  相似文献   

13.
14.
The history of investigation of the common Jurassic and Cretaceous genus Pseudotorellia Florin (Ginkgoales) represented by needle-shaped, narrow linear or lanceolate leaves bearing several veins and characterized by a single type of epidermis, is considered. An extended diagnosis of the genus and its taxonomic composition with regard to the epidermal characters are reported; the stratigraphic and geographical range of its species and the genus evolution are refined. Three new species Pseudotorellia asiatica N. Nosova et Kiritchkova, sp. nov., P. ketoviana N. Nosova et Kiritchkova, sp. nov., and P. samylinae N. Nosova et Kiritchkova, sp. nov. described from the Lower Jurassic (Toarcian) sediments, are proposed as the correlative taxa within the Caspian oil and gas province. The stratotype and reference sections of the Lower Jurassic sediments in the Mangyshlak Mountains are reported for the first time.  相似文献   

15.
The cymatoceratid nautilid genus Anglonautilus is distinguished from most other post-Triassic nautiloids by the occurrence of pronounced fold-like undulating ribs on the phragmocone and early body chamber. Anglonautilus praeundulatus n. sp. is described from the lower Aptian of eastern Spain. It is the first record of this genus from Spain and constitutes the oldest definite representative of the genus. This places the new species at the base of the evolutionary history of Anglonautilus. Its ornamental features confirm the previously assumed close relationship between Anglonautilus and Cymatoceras. An analysis of the ornamental pattern of all species hitherto referred to Anglonautilus indicates that there is an evolutionary lineage leading to the type species of the genus, A. undulatus, and a single successor (A. subalbensis). Several Late Cretaceous species hitherto identified as Anglonautilus (A. japonicus, A. mamiyai, A. suciensis) bear fold-like ribs superficially similar to typical representatives of Anglonautilus. The pattern of ornament in these taxa is very different at closer inspection, though. This suggests that these species developed independently from Cymatoceras. The undulations present in these taxa are interpreted here as a result of convergent evolution. They are therefore excluded from the genus Anglonautilus and provisionally referred to as “Anglonautilus” spp.  相似文献   

16.
牛绍武 《地质通报》2019,38(8):1259-1265
龙凤山藻属(Longfengshania)由叶状体、柄和固着器三部分组成,类似高等植物根、茎、叶的器官分化,分别营光合作用、支撑藻体和固着功能,营海底固着生活。关于其形态学特征,特别是关于它的系统分类一直存在不同看法。根据形态学特征、个体发育中的生物重演律,以及古生态、古气候特征等认为,该属更接近于褐藻门海带目海带科的一些分子,似为海带目的早期原始类型。由于该属藻体较小,叶状体(叶片)全缘无褶皱或刻裂,固着器不分枝足状,与海带科也有较大区别,加之时代久远,在海带目中另立一科也是适宜的,经过适当修订后,进一步确认了龙凤山藻科的存在。对龙凤山藻属与龙凤山藻科的定义进行了重新修订,初步解决了它们的系统分类问题,为古藻类的早期演化提供了化石证据,具有生物学上的重要意义。概述了海藻类各门、纲、目及科级藻类的一般形态学特征,以供对比研究时参考,从而为确定龙凤山藻属的系统分类提供依据。  相似文献   

17.
Lebanoculicoides bloudani a new species of Ceratopogonidae from the Lower Cretaceous ambers of Syria and Lebanon is studied. The new species is characterized, described, illustrated, and compared with the other fossil taxa of the same extinct genus. A key to the species of the genus Lebanoculioides is proposed.  相似文献   

18.
This short section of Skarlato's monograph, Bivalve Mollusks of the Far Eastern Seas of the U. S. S. R. (Order Dysodonta), discusses the genus Arvella Bartsch, 1940 ms. The genus includes the species formerly assigned to Crenella. Diagnostic features of the species included in genus Arvella Bartsch are given. Vilasina Bartsch, 1940 ms is discussed, also The author states that the hinges of Vilasina clearly assign the species to the genus Crenella. The form and position of the umbo relate the species closely to the genus Arvella, though. The almost entirely smooth laminated surface distinguishes Vilasina from both genera, as does the finely serrated ventral edge of the shell. The last section discusses the genus Modiolus Lamarck, 1799. — A. W. Bellais.  相似文献   

19.
A new species of the foraminiferal genus Pseudorhapydionina is reported from the Santonian shallow-water carbonate and mixed deposits of La Cova Unit, in the Montsec and Pedraforca thrust sheets (Southern Pyrenees, NE Spain). Pseudorhapydionina bilottei sp. nov. differs from the Cenomanian species of the genus in its larger test size and the number of chambers in its early planispiral-involute stage. The discovery of P. bilottei sp. nov in the Santonian indicates that the genus Pseudorhapydionina escaped extinction during the Cenomanian-Turonian boundary (CTB) event in the Pyrenean bioprovince. A new subfamily Pseudorhapydionininae is described.  相似文献   

20.
The cirripede Calantica? saskatchewanensis Russell, 1967, from the Maastrichtian Bearpaw Formation of Saskatchewan (Canada), is redescribed on the basis of new material and transferred to the genus Pachyscalpellum Buckeridge, 1991. This considerably extends the known range of the genus from the eastern Tethys (Australasia, Tunisia) to the northern part of the Western Interior Seaway of North America. Species of the genus achieved an exceptionally large size for stalked barnacles, with a projected possible height (capitulum and peduncle) of 150–200 mm.  相似文献   

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