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1.
Perisphinctes Waagen, 1869 is an important genus of the Oxfordian. In many areas the taxon has been excessively and subjectively split. Based on the material collected in Kutch (India), including the type specimens, we have grouped eight species previously described as distinct into one biological species, Perisphinctes indogermanus Waagen, 1875. It is characterized by strong sexual dimorphism. Macroconch shows high intraspecific variability. Microconch is previously described from Kutch in different generic names. Thirteen species of Dichotomosphinctes Buckman, 1926, Perisphinctes Waagen, 1869 and Lithacoceras Hyatt, 1900 are considered here as microconch which is lappeted. The precise age of P. indogermanus is disputed. A detailed stratigraphic analysis of several sections in this study suggests that the species ranges from early to middle Oxfordian. Perisphinctes indogermanus is distinct from other contemporary species of the world and abundant in the Indo-Madagascan Province. Kutch population of P. indogermanus has developed virgatotome style of ribbing in juvenile stage. During the middle Oxfordian marine transgression, the species along with many other ammonites of deeper habitat of the mainland basin reached the shallow shelf of eastern fringe of the Kutch Sea. Being peripherally isolated, it soon underwent an adaptive radiation that resulted in the origination of a new family Ataxioceratidae Buckman, 1921 whose members have neotenously retained the virgatotome ribbing in adult stage. The ataxioceratids later migrated to Europe and flourished during the Kimmeridgian.  相似文献   

2.
The ammonoid subfamily Peltoceratinae is a well-constrained group restricted to the Middle Upper Jurassic; it had a near global distribution. In Kutch (India), they were the most important marine macroinvertebrate group during the upper Callovian–lower Oxfordian. Previous reports suffered from excessive splitting due to failure to account for the large intraspecific variability and sexual dimorphism of these ammonoids. The present systematic revision, based on numerous specimens including many near-complete adult specimens, enables to recognize and describe three species of the genus Peltoceras (P. athleta, P. ponderosum, and P. kumagunense) and two species of the genus Peltoceratoides (P. semirugosus and P. propinquus), as well as identifying their macroconchs and microconchs. We rediscovered Peltoceras athleta, which was previously described by Waagen (1875) but often overlooked by subsequent workers. We were able to identify several morphs within this species that are stunningly similar with those previously reported from France. The presence of P. athleta sensu stricto prompted us to reinstate the Athleta Zone in Kutch, improving intercontinental biostratigraphic correlation. Also, it highlights that the genus Peltoceras has a different biostratigraphic longevity in Kutch: in Europe it is restricted to the upper Callovian, whereas in India it also occurs in the lower Oxfordian.  相似文献   

3.
《Palaeoworld》2014,23(3-4):252-257
Platycrinites was long a “catch-all” genus that was loosely defined in North America. Ausich and Kammer (2009) rectified the inconsistencies of generic diagnoses to define the Platycrinitidae better; however, due to preservation, many species were not known from specimens with sufficient characters to be placed confidently into a genus and, thus, were designated Platycrinites sensu lato. Collicrinus excavates (n. comb.) was one such species. A specimen with a complete theca and partial arms preserved was discovered in southwestern Missouri in the Burlington–Keokuk Limestone. With the discovery of this specimen, C. excavatus has been fully described and placed in the correct genus. Further, the associated fauna of new C. excavatus specimens, reported here, helps to evaluate the stratigraphic position of this species, which is now considered to be only from Burlington Pelmatozoan Association I and II, roughly equivalent to the Dolbee Creek and Haight Creek Members of the Burlington Limestone.  相似文献   

4.
Continuing the revision of the Camaenidae in the Australian Monsoon Tropics, we employed comparative analyses of morphological features (with a focus on shell and penial anatomy) and genetic markers (with a focus on mitochondrial COI and 16S sequences) to address the systematic relationships of land snails from the Victoria River District, Northern Territory, and adjacent East Kimberley (Western Australia). These analyses revealed that the species under study represented the previously undescribed genus Nanotrachia. This genus differs from all other camaenid genera known from north‐western Australia most conspicuously by its small, flat, and ribbed shell. Six species are identified as members of the new genus, four of them new species ( Nanotrachia costulata sp. nov. , Nanotrachia carinata sp. nov. , Nanotrachia coronata sp. nov. , Nanotrachia levis sp. nov. ). Two further species have already been described previously but assigned to different genera. These species, Ordtrachia intermedia (as the type species of Nanotrachia) and Mouldingia orientalis, are here transferred to Nanotrachia. Like other camaenids from the Australian Monsoon Tropics, species of Nanotrachia are characterized by essentially allopatric distributions, regional endemism, and a patchy distribution across their range. © 2013 The Linnean Society of London  相似文献   

5.
《Palaeoworld》2021,30(3):422-429
Schizopholis Waagen, 1885 is a genus of linguliform brachiopod, which is known from Cambrian Stage 4 to the Wuliuan Stage of Australia, Antarctica, Pakistan and China. Recently, new material of Schizopholis was discovered from the upper part of the Tsinghsutung Formation (Cambrian Series 2, Stage 4) near Balang village, Jianhe County, Guizhou Province, China. These specimens display the oval pedicle opening in the ventral valve, a median tongue and a pair of tubercles in the dorsal valve that are characteristic features of Schizopholis napuru (Kruse, 1990). This is the first time that this species has been described from Guizhou Province, China. Previously, fossils of this species are usually preserved in carbonate deposits, but the new material documented herein preserved in mudstone of the Tsinghsutung Formation, providing new information regarding both the paleogeographic distribution and paleoecology of this species.  相似文献   

6.
A review of the microgastropod genus Systenostoma is provided. Thai and Malaysian species are transferred to a new genus, Angustopila (type species: Systenostoma tamlod Panha & Burch, 1999). A new subterranean Angustopila species is described here. Conchologically, the new species is most similar to the cave-dwelling, Thai A. tamlod (Panha & Burch, 1999). One Thai species (Systenostoma edentata) is transferred to the genus Hypselostoma. Vietnamese members remain in the genus Tonkinospira (nomen novum) for Systenostoma Bavay & Dautzenberg, 1908 (non Systenostoma Marsson, 1887). A comprehensive map of former Systenostoma species is presented. SEM and NanoCT images, including a video of A. huoyani sp. n. internal shell morphology, provide novel perspectives of the shells of Angustopila and of the scarcely known Vietnamese Tonkinospira species. The biology of these snails is not yet known but collection localities suggest a troglophilic ecology.  相似文献   

7.
The ultrastructure of three Devonian prasinophycean species (green algae): Inderites reticulatus (Naumova) Telnova, I. devonicus (Naumova) Telnova, and Tasmanites domanicus (Naumova) Telnova is described. Members of the genus Inderites are shown to have double-layer walls (outer homogeneous layer, and inner finely porous layer). The genus Tasmanites is characterized by single-layer (homogeneous) walls. All of the described Paleozoic Tasmanites have a similar ultrastructure. Species differ in shell thickness and distributional pattern of pores.  相似文献   

8.
Three new species of the genus Trachyandra are described, T. hantamensis Boatwr. & J.C.Manning, T. kamiesbergensis Boatwr. & J.C.Manning and T. sanguinorhiza Boatwr. & J.C.Manning. These species form part of a group of morphologically similar species referred to here as the T. thyrsoidea group and are distinguished by their generally small stature, filiform leaves (except for T. tortilis), and simple or shortly branched racemes of patent flowers with maculate tepals. Many of the species in the group have roots that contain abundant anthraquinones, visible as a red substance below the outer skin of the roots, and which is soluble in alcohol, thus often staining herbarium papers purple. A synopsis of the eight species that comprise the T. thyrsoidea group is presented, with maps of each species and illustrations of those described as new.  相似文献   

9.
Based on Yu.L. Pelman’s lingulid collection and our own material, the Early-Middle Cambrian genus Eoobolus, which was widespread on the Siberian Platform, is revised. The Siberian members of this genus have previously been assigned to Lingulella. Two out of these six members are recognized as valid species: Eoobolus siniellus (Pelman) and E. variabilis (Pelman). Lingulella acuta Pelman and L. linguata Pelman are considered here to be junior synonyms of E. priscus (Poulsen, 1932). The valid species are redescribed and their stratigraphic and geographic ranges are given. A new species, E. pelmani sp. nov., is described. New data on the Eoobolus microornamentation and shell structure are provided.  相似文献   

10.
An assemblage of Phlycticeras Hyatt from a precisely dated zone of Middle Callovian in Kutch, India has been analyzed. Systematic study reveals that this sample can be divided into two size groups. The larger set shows different adult modifications leading to ornamental polymorphism. Polymorphs are very similar, if not identical, to different chronospecies of Europe, which range between Middle to Upper Callovian. They are grouped under well-known Phlycticeras polygonium (Zieten). The group of smaller specimens on the other hand, strongly resembles a species, which has been previously described as Phlycticeras schaumburgi (Waagen) from the younger Upper Callovian horizons in Kutch. It has a peculiar ‘rooster’-like septicarinate keel in the venter near adult aperture. Phlycticeras-Oecoptychius have been considered as a possible dimorphic pair since long, but here shown to have many inconsistencies to support these views. Instead, sexual dimorphism is explored within Phlycticeras and P. polygonium-P. schaumburgi is proposed as possible antidimorphs. A similar association is found in different stratigraphic assemblages of Europe. Interestingly these two morphs show parallel evolutionary changes within the Phlycticeras genus.  相似文献   

11.
The shell structure of the Devonian punctate spiriferids Theodossia Nalivkin, 1925, Pyramina Ljaschenko, 1969, Warrenella Crickmay, 1953, Eoreticularia Nalivkin, 1930, Thomasaria Stainbrook, 1945 from the order Spiriferida Waagen, 1883, and also Cyrtina Davidson, 1858 and Punctospirifer North, 1920 from the order Spiriferinida Ivanova, 1972 from the Devonian and Carboniferous of the East European Platform is described.  相似文献   

12.
Among the ascomycete isolates from soil and armadillo dung collected in São Paulo State, Brazil, a new species ofEmericella, E. montenegroi and a new variety ofE. rugulosa, E. rugulosa var.Iazulina are described and illustrated.Emericella montenegroi differs from the other known species of the genus in having ascospores with an incompletely reticulate or ribbed ornamentation on the convex walls.Emericella rugulosa var.Iazulina differs from the type variety in having blue to violet color of ascospores. Isolations ofE. corrugata andE. foveolata are also reported as a South American record. A synoptic key to all accepted species of the genus is provided.  相似文献   

13.
A comparative morphological analysis of all known members of the Lower-Middle Cambrian genus Kutorgina, one of the brachiopod genera with a carbonate shell that are oldest and richest in species. The evolution of the genus is discussed, and the borders between the Kutorgina species are emended. A new species, Kutorgina elanica sp. nov., is described.  相似文献   

14.
《Palaeoworld》2016,25(4):647-661
Plectorthis is a commonly reported Late Ordovician brachiopod genus from Laurentia and several other tectonic plates. Examination of shells from the Cincinnati Arch type area shows that species previously assigned to the genus have a considerable range of variability, such as ribbing style, shell outline, and musculature. The type species, Orthis plicatella Hall, 1847 is characterized by generally simple costae, with double-rowed aditicules on each rib, and a cordate ventral muscle field. Some species previously attributed to Plectorthis have a subtriangular ventral muscle field and hence a closer affinity to the plaesiomyid genus Austinella. Orthis fissicosta is here demoted to a subspecies of Plectorthis plicatella based on its similar ribbing style to some specimens of the type species. In Laurentia, Plectorthis first appeared in the Darriwilian–Sandbian boundary interval, achieved a relatively high species diversity and wide paleogeographic distribution in pericratonic seas during the early Katian; the subequatorial species attained a notably larger shell than those in the higher paleotropics. The genus did not invade the intracratonic basins of Laurentia and became extinct by the late Katian.  相似文献   

15.
Fossil mesostigmatid mites (Acari: Parasitiformes: Mesostigmata) are extremely rare, and specimens from only nine families, including four named species, have been described so far. A new record of Myrmozercon sp. described here from Eocene (ca 44–49 Myr) Baltic amber represents the first—and so far only—fossil example of the derived, extant family Laelapidae. Significantly, modern species of this genus are habitually myrmecophilous and the fossil mite described here is preserved attached to the head of the dolichoderine ant Ctenobethylus goepperti (Mayr, 1868). It thus offers the oldest unequivocal evidence for an ecological association between mesostigmatid mites and social insects in the order Hymenoptera.  相似文献   

16.
Ceriporia accommodates a kind of wood-inhabiting polypores producing resupinate basidiocarps and causing a white rot. More than 30 species of this genus have been described; however, only a few species were referred to molecular phylogeny. In this study, a total of 203 specimens of Ceriporia were studied morphologically, and the ITS and/or nLSU regions from 42 samples, representing 18 species, were sequenced for phylogenetic analysis. Based on both morphological and phylogenetic analyses, three new species of Ceriporia, C. bubalinomarginata, C. pseudocystidiata and C. variegata, are described and illustrated. An annotated identification key is provided for all 20 species of this genus thus far known in China. Our phylogeny shows that (1) Ceriporia is not monophyletic, (2) C. spissa and C. viridans as morphologically circumscribed are polyphyletic, (3) C. inflata is retained for both C. inflata and C. jiangxiensis, and (4) presence or absence of hymenial cystidia is not a useful character in delimiting species relationships in Ceriporia.  相似文献   

17.
Members of the new family Pugnellidae have long been considered to represent the earliest members of the Strombidae but have more recently been included with the Aporrhaidae. We here propose them to represent a new family since their low-spired, bulgous shells are quite distinct from the usually slender and high-spired shell of the Aporrhaidae. Eleven species are described here belonging to six genera from which one genus and five species are new. The new genusBizarrus includes large, unornamentedGymnarus-like species, and new species are described asPugnellus klitzschi, Perustrombus africanus, Perustrombus indicus, Pugnellus?bartheli andPyktes popenoei. The here described Pugnellidae are from the Coniacian/ Santonian of Mungo River in Cameroon, the Santonian Umzamba Formation in the Eastern Cape Province of South Africa, the Campanian-Maastrichtian Ariyalur Group in Tamil Nadu, southern India, the Maastrichtian Quiriquina Formation of central Chile and the Maastrichtian Ammonite Hill Formation in the Western Desert of Egypt. Their radiation and possible phylogenetic relations to other Late Cretaceous stromboids are discussed. The origin of this family appears to lie in eastern Asia from where they spread through the Indopacific, Tethys and Atlantic Oceans during the Cenomanian-Santonian before they finally reached eastern North America in the Campanian.  相似文献   

18.
A high degree of intraspecific variation, both genetic and in shell morphology, of the operculate land snail Cyclophorus fulguratus (Pfeiffer, 1854) suggests that its classification as a single species warrants reconsideration. We sequenced two nuclear (18S and 28S) and two mitochondrial (16S and COI) genes of 46 C. fulguratus specimens and used them to estimate the phylogeny and to determine the validity of species boundaries. Molecular phylogenetic analyses revealed the presence of three lineages corresponding to three geographically disjunctive populations of C. fulguratus in Thailand. Likelihood tests of topologies significantly supported the non-monophyly of the C. fulguratus–complex and Bayesian species delimitation analysis significantly supported the potential representation as distinct species of these three lineages. Discriminant function analysis based on geometric-morphometrics of shell shape allowed for significant distinction of these three candidate species, although they revealed a considerable degree of overlap of shell shape reflecting their crypsis morphologically. The diagnostic characters are provided by color pattern, pattern of protoconch and pattern of jaw. In conclusion, the results support that the C. fulguratus s.l., as currently recognized, consists of three distinct species in Thailand: C. fulguratus s.s., C. rangunensis and C. abditus sp.nov., which are described herein.  相似文献   

19.
ABSTRACT

Euathlus

Ausserer, 1875 is a South American genus of spiders of the family Theraphosidae known from Chile and Argentina. Three new species from Argentina: Euathlus mauryi sp. n. (from San Juan province), Euathlus grismadoi sp. n. (from La Rioja province), and Euathlus pampa sp. n. (from Salta province) are described here. New records of the previous species Euathlus diamante and Euathlus tenebrarum are contributed. The distribution of these new species expands the geographical distribution of the genus along the Andean hills, with Salta province as the northernmost record of the genus. A key is provided for identification of Euathlus species as well as a map with all the records in Argentina.  相似文献   

20.
Yarrowia lipolytica is the only known species in the teleomorph (i.e. sexual) genus Yarrowia and has its anamorph (i.e. asexual state) classified in the genus Candida Berkhout as Candida lipolytica. This species can be found readily in nature, has significant industrial value and is important to the food and medical fields. Candida deformans was first considered a variety of C. lipolytica and was later listed as a synonym of this species. More recent studies based on sequence variation in the nuclear rRNA gene sequences suggested C. deformans to be a separate species with no known teleomorph linked to it. In this study we show that C. deformans strains, obtained from South Africa, can mate with strains present in the CBS yeast collection and produce a Yarrowia teleomorph, described here as Yarrowia deformans. Strains of Candida yakushimensis nom. inval., a species also belonging to the Yarrowia phylogenetic clade, were also studied and described as a novel species of Yarrowia.  相似文献   

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