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1.
Limanthes vinculans (Limnanthaceae) is described as a new species belonging to section Reflexae. It is endemic to a small area of Sonoma County, California, and is most closely related toL. douglasii andL. bakeri.  相似文献   

2.
In 1909, the famous paleontologist Louis Dollo identified two putative new species of giant soft-shelled turtles from the lowest Eocene record of Belgium, ‘Trionyx erquelinnensis’ and ‘Trionyx levalensis’, from Erquelinnes and Leval, respectively. However, these proposals did not meet the requirements of the International Code of Zoological Nomenclature, so they were considered as nomina nuda. The information on these specimens or about any other specimen of this lineage of giant turtles from the Belgian record is currently extremely limited. Relatively scarce material from giant trionychids has been described for the lower Eocene record of other European regions. Considering the available information, all the European material has recently been recognized as belonging to the genus Axestemys, which has a North American origin, and possibly attributable to a single species, Axestemys vittata, which currently lacks a diagnosis. Numerous and well-preserved Belgian specimens are deposited in the Royal Belgian Institute of Natural Sciences. In addition to the cited individuals from Erquelinnes and Leval, additional specimens from both localities, as well as others from Orp-le-Grand, are part of this collection. These specimens, found between the decades of 1910 and 1930, have been recently restored, and their study is carried out here. The presence of Axestemys vittata in Belgium (in Leval and Orp-le-Grand) is confirmed. Knowledge about this species is significantly improved, and a diagnosis is proposed. However, the hypothesis proposed by Dollo is here confirmed, this species being not the only identified in the Belgian record. So, Axestemys erquelinnensis nov. sp. is defined based on the carapace from Erquelinnes known by Dollo, suggesting that the genus probably reached Europe during the Paleocene Eocene Thermal Maximum.  相似文献   

3.
Billie L. Turner 《Brittonia》1986,38(2):168-170
Coreopsis queretarensis, a new species from northeastern Mexico belonging to sectionPseudoagarista, is described and illustrated. It is closely related toC. mevaughii of Nueva Galicia but is readily distinguished by leaf shape, involucral bracts, and details of corolla.  相似文献   

4.
We diagnose new subfossil specimens belonging to the extinct palaeopropithecid, Mesopropithecus,from several caves at the Ankarana massif in northern Madagascar. They include three partial crania with mandibles, and the first vertebrae, ribs, clavicle, pelvis, ulna, and hand and foot bones of Mesopropithecusever found. Several other postcranial elements are known for this northern variant of Mesopropithecusand for previously described species from central and southern Madagascar. The new materials cannot be accommodated in either currently recognized species of this genus and are,hereby, given the name Mesopropithecus dolichobrachion. M. dolichobrachionis the second new species of extinct subfossil lemur to be found in the caves of Ankarana. It is unlike the two previously described species of this genus primarily in its larger size, different limb proportions, and aspects of its long bone morphology. Most notable is the fact that this is the only species of Mesopropithecuswith the forelimb longer than the hind limb— hence the name, the “long-armed” Mesopropithecus.Various characteristics place M. dolichobrachionphenetically closest (of species belonging to Mesopropithecus)to Babakotia radofilai, Archaeoindris,and Palaeopropithecus.If these similarities are derived specializations rather than primitive for palaeopropithecids, a new generic name will be required.  相似文献   

5.
Location of thePoteriocrinus impressus Phillips 1836 holotype has not been known, but it was discovered in the collections of the Natural History Museum, London. Rather than belonging toBlothrocrinus, as suggested by more recent authors, this species should be reassigned toPoteriocrinites. Poteriocrinites impressus is redescribed and photographically illustrated for the first time.  相似文献   

6.
A taxonomic study of the stipitate terrestrial hydnums of Florida was undertaken. Eleven species belonging toHydnellum, Phellodon, andSarcodon were found. Of these,Phellodon implicatus is described as new and a microscopic analysis showed that this species is the second knownPhellodon with abundant clamp connections in the tramal tissue.  相似文献   

7.
8.
From the Lower Devonian of Nevada (USA) a newly discovered ammonoid,Mimagonia- titesi n. sp., aff.M. angulostriatus Bogoslovski 1969, is described. The specimen was found in strata belonging to the highserotinus Zone of the conodont chronology resp. the lowerholynensis Zone according to the tentaculite zonation (late Dalejan resp. Upper Emsian). Suture line and umbilicus are not preserved; therefore the systematic position is not fully verified. But the fragmentary shell provides strong indications toMimagoniatites Eichenberg, a genus up till now unknown from the central Cordilleran Province.  相似文献   

9.
Two desert shrubs belonging toEriogonum subgen.Eucycla sect.Corymbosa are described from southern Utah and northern Arizona.Eriogonum mortonianum, endemic to red clay hills southwest of Fredonia, in extreme northeastern Mohave County, Arizona, is most closely related toE. smithii, a species endemic to the San Rafael Desert of Emery County, Utah, but differs in having wider leaves, a much more branched inflorescence, and smaller, pale-yellow or white flowers.Eriogonum leptocladon var.papiliunculi, found in central Garfield and eastern Kane counties, Utah, southward into northern Coconino and Navajo counties, Arizona, is distinguished from var.leptocladon by its white flowers and from var.ramosissimum by its glabrous stems.  相似文献   

10.
11.
According to Rosen (Bull. Math. Biophysics,23, 305–318, 1961) the forming of the first genes in natural history can be understood in terms of stochastic building of words. The genes are supposed to represent quasiergodic words of great length. For a word of lengthN, belonging to the free monoid with base ofn elements, a formula is given for the probability of its belonging to some quasiergodic submonoid. Restricting ourselves ton=2, we give an estimate for an upper and a lower bound of the limit of this probability asN tends to infinity. Result: If the tolerance ε does not exceed a certain value depending only on the mean relative frequencies (p 1,p 2,...) of the quasiergodic submonoid, the upper bound for the limit of the probability is zero. Concluding remarks are added to show the meaning of our results to the biologists.  相似文献   

12.
Methane oxidation by microorganisms inhabiting aerobic soils is a key process involved in the regulation of the concentration of this significant greenhouse gas in the atmosphere; however, the microorganisms responsible for this process remain unknown. Three stable methane-oxidizing cultures were isolated from samples of forest soils (FS) and agricultural soils (AS) of Moscow oblast, as well as from soil samples collected from a Belgian agrocenosis (BS). The obtained enrichment cultures exhibit a high affinity for methane; their km values range from 54.2 to 176.8 nM CH4 and are comparable to those of aerobic soils. Analysis of the fragments of the ribosomal (16S rRNA) and functional (pmoA) genes of methanotrophs by PCR— DGGE and cloning demonstrated the presence of bacteria belonging to the genera Methylocystis in FS, Methylosinus in AS and BS, and Methylocella in BS. It was established that Methylocystis and Methylosinus detected in the enrichment cultures contain the genes encoding the synthesis of the active center of two membrane-bound particulate methane monooxygenases; it is likely that one of these genes (pmoA2) is responsible for the capacity of these microorganisms for oxidation of atmospheric methane.  相似文献   

13.
Chromosome numbers of some new world species of Thelypteris   总被引:1,自引:1,他引:0  
Alan R. Smith 《Brittonia》1971,23(4):354-360
Chromosome numbers of 19 species ofThelypteris from Florida, California, Mexico, and Costa Rica are reported. First counts are given for two species belonging to sect.Goniopteris (x = 36), one species of sect.Leptogramma (x = 36) and seven species of the Opposita group (x = 29). The last named group is remarkable for the relatively low number of diploid taxa so far known. The base numbers 36, 35, 34, 32, 31, 30, 29, and 27 are known in the Thelypteridaceae, with 36 being the most common number throughout the tropics, and perhaps the ancestral base number. The temperate American species ofThelypteris are probably more closely allied toParathelypteris H. Ito, from Asia, than to the Neotropical species of the Opposita group.  相似文献   

14.
(GTG)5-PCR fingerprinting and pheS sequence analysis of 18 Lactobacillus rossiae isolates, mainly originating from Belgian and Italian artisan sourdoughs, revealed intraspecies grouping as evidenced by the delineation of three and two subgroups, respectively. On the other hand, 16S rRNA and rpoA gene sequence analysis and DNA–DNA hybridizations supported the accommodation of all isolates in a single species. No correlation between genetic and phenotypic heterogeneity was observed. Collectively, these data do not warrant taxonomic division of L. rossiae. On the other hand, the considerable differences in intraspecies sequence variation of L. rossiae isolates displayed by the pheS (9.8%) and rpoA (1.1%) genes highlight that the discriminatory power of housekeeping genes as alternative genomic markers for the 16S rRNA gene in the identification of Lactobacillus species may significantly differ from gene to gene. In conclusion, this study has demonstrated that a polyphasic approach remains highly useful for identification of isolates belonging to genotypically heterogeneous species such as L. rossiae.  相似文献   

15.
A new species of Nitella belonging to the N. flexilis species group is described. The neiu species shows definite relationships to N. flexilis, N. opaca, N. missouriensis, and N. mirabilis. Relationships of the new species to N. acuminata are also discussed.  相似文献   

16.
Production of phosphatates by fungi isolated from desert soils   总被引:1,自引:0,他引:1  
Twelve fungal cultures isolated from Indian desert soils belonging toAspergillus, Penicillium, Acrophialophora andAlternaria were found to produce both acid and alkaline phosphatases in liquid medium, their amounts varying from culture to culture. Maximum production of these enzymes was observed withA. niger. In general, acid phosphatase activity was much higher as compared to alkaline phosphatase. The optimum incubation period for the production of these enzymes was found to be 14 d and thereafter it started declining. There was a significant and positive correlation between biomass production and acid phosphatase activity but not with alkaline phosphatase.  相似文献   

17.
Belgian Blue cattle are known for their high degree of muscling and good carcass qualities. This high degree of muscling is mainly caused by a mutation in the myostatin gene (MSTN). Although the MSTN mutation is considered as fixed in the Belgian Blue breed, segregation is occurring in a sub-population bred for dual purpose. In the latter population, we observed an association between the mutation in MSTN and susceptibility to psoroptic mange, a skin disease caused by Psoroptes ovis mites that heavily plagues Belgian Blue cattle. In total, 291 animals were sampled and screened for their susceptibility for mange lesions and their MSTN genotype. Via linear mixed modelling, we observed that homozygous mutant animals had a significant increase in the size of mange lesions (+2.51% lesion extent) compared to homozygous wild type. These findings were confirmed with zero-inflated modelling, an animal model and odds analysis. Risk ratios for developing severe mange lesions were 5.9 times as high for homozygous mutant animals. All analyses confirmed an association between the MSTN genotype and psoroptic mange lesion size.  相似文献   

18.
Investigation on karyotype, 4C nuclear DNA amount and interphase nuclear volume (INV) of different HimalayanBupleurum species belonging toUmbelliferae revealed genetic differentiation. Numerical and structural alternation of chromosomes in interspecific level were manifested in their statistically significant altered species specific 4C nuclear DNA content. Somatic chromosome number ranged between 2n = 14 and 2n = 16.B. himalayense was reported for the first time having 2n = 16 chromosomes. Correlation coefficient among the various chromosomal and nuclear parameters showed no significant progressive or regressive interdependence except in between INV and nuclear DNA amount. Critical differences between 4C DNA content showed interspecific variation.  相似文献   

19.
Arnold Tiehm 《Brittonia》1985,37(4):344-346
Silene nachlingerae is described, illustrated, and compared toS. aperta. The similarly floweredS. invisa is considered to be closely related toS. bernardina, and especially to its var.rigidula (Robinson) Tiehm, comb nov.  相似文献   

20.
A survey on the presence, microbial diversity, and population dynamics of lactobacilli in Grana cheese is presented. Evolution of thermophilic rod lactic acid bacteria within the first two days from cheese making and during ripening was different according to different bacterial groups, which were selectively enumerated and identified by molecular methods. Species-specific microbial counts indicated prevalence ofLactobacillus helveticus in both the whey starter and the cheese at moulding, and ofLactobacillus delbrueckii subsp.lactis in cheese after two months of ripening. In more advanced ripening, a decrease of total thermophilic lactobacilli and an increase of mesophilic lactobacilli (mostly belonging toLactobacillus casei/paracasei andLactobacillus rhamnosus) was observed. PCR fingerprinting of lactobacilli, which was performed by PCR-fingerprinting, indicated a marked microbial heterogeneity within theLactobacillus spp. populations, which enabled strain (or group)-specific fingerprints to be observed.  相似文献   

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