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1.
The theca and the columnals of twenty-two lateCretaceous species of the genus Bourgueticrinus (including two new species), of one species of the genus Democrinus, of four species of the genus Conocrinus (including one new species) and of one species of the genus Paleobathycrinus known from USSR are figured and shortly described. Biometric reconstructions of stems for B. aequalis, B. bellus, B. danicus, B. fischeri and C. tauricus nov. sp. are given. A new index is used to suggest the relative flexibility of stem. Decrease in dimension and flexibility of the arms in several species take place simultaneously with an increase of stem flexibility. This fact seems to be closely related to environmental changes.  相似文献   

2.
We describe a new nematode species, Baylisascaris potosis n. sp., isolated from captive kinkajou, Potos flavus, from the Cooperative Republic of Guyana. The nematode was found in fecal specimens, identified morphologically, and confirmed genetically. The new species is similar to Baylisascaris procyonis, Baylisascaris columnaris, and other Baylisascaris species, but is distinguished by the position of the male phasmidial pole. Nuclear and mitochondrial DNA sequence analyses confirmed that the new species is phylogenetically distinct from all the members of the genus Baylisascaris, and groups with B. procyonis and B. columnaris. This nematode is the 10th species assigned to the genus Baylisascaris.  相似文献   

3.
Paul A. Fryxell 《Brittonia》1976,28(3):318-325
Two new species ofBriquetia,B. sonorae andB. inermis, are described from northern Mexico, and another species that ranges from Mexico to Bolivia is transferred into the genus asB. spicata. The genus (previously known as monotypic, Paraguayan-Brazilian) is thereby enlarged from one species to four, and its geographical and morphological limits are greatly expanded. Also, a Mexican species ofAbutilon is transferred toHochreutinera, asH. amplexifolia, enlarging that genus from one to two species. On the basis of this new information, the limits of the informalBriquetia alliance are reconsidered; it is considered to include onlyBriquetia, Dirhamphis, andBatesimalva.  相似文献   

4.
The modern walrus, Odobenus rosmarus, is specialized and only extant member of the family Odobenidae. They were much more diversified in the past, and at least 16 genera and 20 species of fossil walruses have been known. Although their diversity increased in the late Miocene and Pliocene (around 8–2 Million years ago), older records are poorly known. A new genus and species of archaic odobenid, Archaeodobenus akamatsui, gen. et sp. nov. from the late Miocene (ca. 10.0–9.5 Ma) top of the Ichibangawa Formation, Hokkaido, northern Japan, suggests rapid diversification of basal Miocene walruses. Archaeodobenus akamatsui is the contemporaneous Pseudotaria muramotoi from the same formation, but they are distinguishable from each other in size and shape of the occipital condyle, foramen magnum and mastoid process of the cranium, and other postcranial features. Based on our phylogenetic analysis, A. akamatsui might have split from P. muramotoi at the late Miocene in the western North Pacific. This rapid diversification of the archaic odobenids occurred with a combination of marine regression and transgression, which provided geological isolation among the common ancestors of extinct odobenids.  相似文献   

5.
Bradyrhizobium are N2-fixing microsymbionts of legumes with relevant applications in agricultural sustainability, and we investigated the phylogenetic relationships of conserved and symbiotic genes of 21 bradyrhizobial strains. The study included strains from Western Australia (WA), isolated from nodules of Glycine spp. the country is one genetic center for the genus and from nodules of other indigenous legumes grown in WA, and strains isolated from forage Glycine sp. grown in South Africa. The 16S rRNA phylogeny divided the strains in two superclades, of B. japonicum and B. elkanii, but with low discrimination among the species. The multilocus sequence analysis (MLSA) with four protein-coding housekeeping genes (dnaK, glnII, gyrB and recA) pointed out seven groups as putative new species, two within the B. japonicum, and five within the B. elkanii superclades. The remaining eleven strains showed higher similarity with six species, B. lupini, B. liaoningense, B. yuanmingense, B. subterraneum, B. brasilense and B. retamae. Phylogenetic analysis of the nodC symbiotic gene clustered 13 strains in three different symbiovars (sv. vignae, sv. genistearum and sv. retamae), while seven others might compose new symbiovars. The genetic profiles of the strains evaluated by BOX-PCR revealed high intra- and interspecific diversity. The results point out the high level of diversity still to be explored within the Bradyrhizobium genus, and further studies might confirm new species and symbiovars.  相似文献   

6.
During the Miocene, the Abruzzo/Apulia region (Italy), isolated from the continent, was the theatre of the evolution of a vertebrate ecosystem in insular context. During the Late Miocene, the protagonists of this ecosystem called “Mikrotia fauna” show a high endemic speciation level, presenting spectacular giant and dwarf species of mammals and birds. Deinogalerix is one of the most uncommon forms of this peculiar fauna. It is the largest Galericinae that ever lived. From Gargano (Apulia, Italy) deposits (also called “Terre Rosse”), Deinogalerix has been, since its discovery in the 1970s’, the subject of two publications in which various morphotypes were described. Its presence is also attested at Scontrone (Abruzzo, Italy). In 2005, the new Miocene fissure “Mikrotia 013” (M013) was found in the Gargano area at Cava Dell’Erba by a team of the Università degli studi di Torino. The study of the micromammals, and in particular the presence of an archaic form of Mikrotia, attests that M013 is the oldest fissure known to date. All the Deinogalerix remains come from the smallest morphotype ever found. The morphological features (other than size) allow us to describe the new species Deinogalerix masinii. It presents a large variability of dental and mandibular features expressed in mosaic patterns within the material: the robustness of the upper and lower P3 and P4, and the characteristic trigonid of m1 of the genus; the archaic morphology of the maxilla and the mandible; the abrading pattern of the teeth are unique for Deinogalerix. These new remains allow us to update the knowledge of Deinogalerix. The suit of characters testified that D. masinii nov. sp. is an archaic form on the evolutionary trend toward the most derived representatives of the genus. The affinities of Deinogalerix with the Parasorex group are confirmed, but the time of immigration in Gargano remains debated.  相似文献   

7.
A new ammonite genus of the subfamily Garantianinae, family Stephanoceratidae, from the Upper Bajocian Strenoceras niortense Zone in the Bolshoi Zelenchuk River basin (Karachay-Cherkessia), with two new species from two different localities, is established. The type species Keppleritiana rostovtsevi gen. et sp. nov. is homeomorphic to some species of the Upper Bathonian–Lower Callovian genus Kepplerites (Fam. Kosmoceratidae) but is distinguished by the presence of a ventral furrow in adults. An isolated valve of an aptychus possibly belonging to this species is illustrated. Keppleritiana graebensteini sp. nov. has a more archaic morphology and is apparently ancestral to the type species. The macroconchs and microconchs of both species are described.  相似文献   

8.
The systematic position of three Apiaceae taxa, Carum piovanii, Bunium nothum and Bunium kandaharicum, is clarified based on morphological and nrITS sequence data. The phylogenetic analyses place C. piovanii within the African peucedanoid genus, Afroligusticum and not with its congeners. Although C. piovanii differs considerably from Afroligusticum in underground organs (spindle-shaped or subcylindrical tubers vs. rhizomatous woody rootstocks), size of leaflets (up to 4 mm long vs. over 8 mm long), and petal color (white vs. mostly greenish or yellow), it is similar carpologically (obtuse-keeled dorsal ribs and narrowly-winged marginal ribs). As a result the new combination Afroligusticum piovanii is proposed. A new section, Austrobunium, is described to accommodate the South Indian B. nothum based on the well-developed calyx teeth not found in the rest of the genus. The Afghanian species, B. kandaharicum, is reduced into synonym with Elwendia stewartiana.  相似文献   

9.
The role of neolignans in the chemotaxonomy of the genus Prunus has long been neglected. In this study, two new dihydrobenzofuran neolignans tomentosanans A (12) and B (14), together with 15 known neolignans, were isolated from the seeds of Prunus tomentosa. This is the first report on the occurrence of compounds 1–12, 14, 15 and 17 in the genus Prunus. The biosynthetic pathways of these neolignans are also summarized. Together, these neolignans represent a phytochemical fingerprint for P. tomentosa, which may be used for identification of Prunus species.  相似文献   

10.
Exceptionally well-preserved skulls and postcranial elements of a new species of the plesiomorphic stem macropodiform Balbaroo have been recovered from middle Miocene freshwater limestone deposits in the Riversleigh World Heritage Area of northwestern Queensland, Australia. This constitutes the richest intraspecific sample for any currently known basal “kangaroo”, and, along with additional material referred to Balbaroo fangaroo, provides new insights into structural variability within the most prolific archaic macropodiform clade – Balbaridae. Qualitative and metric evaluations of taxonomic boundaries demonstrate that the previously distinct species Nambaroo bullockensis is a junior synonym of B. camfieldensis. Furthermore, coupled Maximum Parsimony and Bayesian phylogenetic analyses reveal that our new Balbaroo remains represent the most derived member of the Balbaroo lineage, and are closely related to the middle Miocene B. camfieldensis, which like most named balbarid species is identifiable only from isolated jaws. The postcranial elements of Balbaroo concur with earlier finds of the stratigraphically oldest balbarid skeleton, Nambaroo gillespieae, and suggest that quadrupedal progression was a primary gait mode as opposed to bipedal saltation. All Balbaroo spp. have low-crowned bilophodont molars, which are typical for browsing herbivores inhabiting the densely forested environments envisaged for middle Miocene northeastern Australia.  相似文献   

11.
12.
The economically important genus Arachis (Fabaceae) comprises 80 species restricted to South America. One monograph on the genus divided it into nine sections and included an intuitive assessment of evolutionary relationships. There is no comprehensive phylogenetic study of the genus. To test the current systematic treatment of the genus, we reconstructed a phylogeny for Arachis using nuclear ITS and plastid trnT–trnF sequences from 46 species representing all nine sections. ITS cloning of the allotetraploid species of section Arachis indicated the presence of A and B genome alleles and chimeric sequences. Our study revealed that species from section Extranervosae were the first emerging lineage in the genus, followed by sections Triseminatae and Caulorrhizae, and two terminal major lineages, which we refer to as erectoides and arachis. The lineage erectoides comprises members of sections Erectoides, Heteranthae, Procumbentes, Rhizomatosae, and Trierectoides. Species in the arachis lineage form two major clades, arachis I (B and D genomes species and the aneuploids) and arachis II (A genome species). Our results substantiated the sectional treatment of Caulorrhizae, Extranervosae, and Triseminatae, but demonstrated that sections Erectoides, Procumbentes, and Trierectoides are not monophyletic. A detailed study of the genus Arachis with denser taxon sampling, additional genomic regions, plus information from morphology and cytogenetics is needed for comprehensive assessment of its systematics.  相似文献   

13.
14.
The four species of the central African genus Barteria show variation in habitat and in degree of association with ants. Whereas B. solida, restricted to submontane forests, attracts opportunistic ants to extrafloral nectar, the three other species, found in lowland rainforests (B. fistulosa, B. dewevrei) and in littoral scrub (B. nigritana), possess stem domatia of varying shapes and degrees of specialisation, hosting either non-specific arboreal ants (B. nigritana, some B. dewevrei) or two large species of ants of the genus Tetraponera Smith, 1852 that are specific to some species of Barteria (B. fistulosa, some B. dewevrei). We aimed to investigate whether this variation represents an evolutionary trend toward increasing specialisation of mutualism or the reduction or loss of myrmecophytic traits. For this, we determined phylogenetic relationships within the genus using DNA sequences (primarily nuclear ITS) and microsatellite genotypes (11 loci) on a large sample of individuals, mostly from Cameroon and Gabon. The two types of markers support an initial dichotomy that groups B. dewevrei with B. nigritana and B. fistulosa with B. solida respectively. Within these pairs, species do not appear reciprocally monophyletic. At microsatellite loci, B. nigritana forms a clade embedded within B. dewevrei; and within both B. solida and B. fistulosa, geographical populations show levels of differentiation similar to that observed between populations of B. solida and B. fistulosa. Geographic distance alone does not account for genetic differentiation between species, which indicates reproductive isolation. Divergence in each of the two pairs implies evolutionary transitions in habitat and in myrmecophytism. Specialised mutualism with specific ant species of the genus Tetraponera has been lost in species found in more marginal habitats.  相似文献   

15.
Balantidiasis is considered a neglected zoonotic disease with pigs serving as reservoir hosts. However, Balantidium coli has been recorded in many other mammalian species, including primates. Here, we evaluated the genetic diversity of B. coli in non-human primates using two gene markers (SSrDNA and ITS1-5.8SDNA-ITS2). We analyzed 49 isolates of ciliates from fecal samples originating from 11 species of captive and wild primates, domestic pigs and wild boar. The phylogenetic trees were computed using Bayesian inference and Maximum likelihood. Balantidium entozoon from edible frog and Buxtonella sulcata from cattle were included in the analyses as the closest relatives of B. coli, as well as reference sequences of vestibuliferids. The SSrDNA tree showed the same phylogenetic diversification of B. coli at genus level as the tree constructed based on the ITS region. Based on the polymorphism of SSrDNA sequences, the type species of the genus, namely B. entozoon, appeared to be phylogenetically distinct from B. coli. Thus, we propose a new genus Neobalantidium for the homeothermic clade. Moreover, several isolates from both captive and wild primates (excluding great apes) clustered with B. sulcata with high support, suggesting the existence of a new species within this genus. The cysts of Buxtonella and Neobalantidium are morphologically indistinguishable and the presence of Buxtonella-like ciliates in primates opens the question about possible occurrence of these pathogens in humans.  相似文献   

16.
From a total of 80 bacterial strains isolated from root nodules of Lupinus angustifolius grown wild in the North-Eastern Algerian region of El Tarf, 64 plant host-nodulating strains clustered into 17 random amplified polymorphic DNA (RAPD) fingerprinting groups. The nearly complete 16S rRNA gene sequence from the representative strain of each group revealed they were closely related to members of the genus Bradyrhizobium of the Alphaproteobacteria, but their affiliation at the species level was not clear. Sequencing of the housekeeping genes glnII and recA, and their concatenated phylogenetic analysis, showed that 12 strains belong to B. lupini, other 2 strains affiliated with B. diazoefficiens and that 1 strain was closely related to B. japonicum. The remaining two strains showed similarity values ≤95% with B. cytisi and could represent new lineages within the genus Bradyrhizobium. Sequencing of the symbiotic nodC gene from 4 selected bradyrhizobial strains showed they were all similar to those of the species included in symbiovar genistearum.  相似文献   

17.
主要是利用核基因组的核糖体DNA内转录间隔区(nrDNA ITS)序列数据探讨了Buck和Goffinet(2000)限定的真藓科内各属间及属内种间的系统发育关系。ITS序列的最大简约法(MP)及贝叶斯推论(BI)分析结果显示:不支持Cox(1999)利用rps4/trnL-trnF数据分析将丝瓜藓属移至提灯藓科的结论。ITS数据分析与Holyoak(2007)利用trnL-F,trnG和atpB-rbcL序列数据分析将Bryum algovicumB.caespiticiumB.capillareB.pseudotriquetrumPlagiobryum zierii划归Ptychostomum的结论一致,同时,为Spence(2005)依据形态学特征将B.pallescenB.pallensB.uliginosumB.amblyodonB.lonchocaulon划归Ptychostomum提供ITS分子证据支持。基于以上研究,建议将以上提到的真藓属种和平蒴藓移至Ptychostomum。  相似文献   

18.
A new species of the Recent genus Enophrys, E. hoplites sp. nov., is described from the Miocene (Serravalian?Tortonian) Agnevo Formation of Sakhalin Island, Russia. This Miocene species differs from two Recent congeners in the greater number of anal fin rays (14 versus 9?13), the smaller head, less raised margins of the orbit, flatter upper contour of the head, longer anal fin base, short predorsal distance, higher first dorsal fin, and in the right angle (versus acute angle) between two upper preopercular spines. An archaic feature of the new species is the presence of two rays on the posterior pterygiophore of the anal fin, a character recorded only in the most primitive Recent members of the family. The occurrence of this new fossil species shows that extant subfamilies, tribes, and genera existed as a part of the family Cottidae as early as the Miocene time.  相似文献   

19.
A new genus and species from Mexico,Metastevia hintonii, is described. The genus, considered to be closely related to and derived fromStevia, differs in seven morphological features from all known species ofStevia. The reasons for recognizing the new genus are discussed in detail.  相似文献   

20.
《Mycological Research》2006,110(6):646-656
Bremia graminicola (Chromista, Peronosporales) is a common downy mildew pathogen of Arthraxon spp. (Poaceae) in Central to East Asia and the only species of Bremia parasitic on grasses. Despite its widespread occurrence and apparent differences in host range and morphology compared with other species of the genus, its placement in Bremia has not been challenged for the past 90 y. Its current taxonomic position is revised based on sporangiophore morphology and ultrastructure, haustorium morphology, and nu-rDNA sequence analysis. Haustorium morphology and sporangiophore ultrastructure indicate that B. graminicola is not a member of the genus Bremia, which shows affinities to Plasmopara and Paraperonospora. Based on haustorium morphology, B. graminicola appears to be more closely related to Viennotia oplismeni, although the sporangiophore morphology is strikingly different between these two taxa. This is supported by molecular analyses based on a near-representative sample of nuLSU rDNA sequences of downy mildew genera, whereby B. graminicola is revealed as the sister taxon of V. oplismeni with 100 % BS support under all phylogenetic optimality criteria applied. Relationships of this clade to other groups are less clear. However, network and reduced-consensus analyses show that this lack of resolution is mainly due to the ambiguous molecular affinities of Sclerospora graminicola. Omitting this highly divergent taxon results in considerable support for a clade comprised of taxa with globose to pyriform haustoria, including B. lactucae, and for the sister-group relationship of B. graminicola and V. oplismeni with Hyaloperonospora. Consequently, a new genus, Graminivora, is described to accommodate B. graminicola.  相似文献   

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