首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Topotype specimens of the Middle OrdovicianHyolithes acutus Eichwald, 1840, which is the type of the genus that lent its name to a family, order, class, and even phylum according to some, andH. latus Eichwald, 1860 allow that genus and those species to be firmly established on a sound, morphologic basis. In addition, preservation of the types ofHyolithes striatus Eichwald, 1860 is sufficiently good to warrant reassignment toDorsolinevitus Syssoiev, 1958. In contrast, the type ofH. insularis Eichwald, 1860 is incompletely preserved, and this species is not recognizable beyond the type material. The concept of the family Hyolithidae is revised to more closely conform to the morphology ofHyolithes, with authorship herein ascribed toSyssoiev (1958) rather than toNicholson (1872). The stratigraphic distribution of these taxa suggests thatHyolithes as defined herein first appears in the Middle Ordovician, but extends into at least the Lower Devonian, as suggested by two species from the Barrandian region of the Czech Republic. Their geographic distribution further re-enforces the notion of two distinct paleobiogeographic provinces based on hyoliths, a Mediterranean province and Baltic province, with almost no mixing of hyolith faunas during the Ordovician.   相似文献   

2.
Mobergellans are disc-shaped problematic fossils of phosphatic composition bearing prominent muscle attachment structures on the presumed internal surface. They are found exclusively in sediments of Early Cambrian age, mainly from Laurentia, Baltica and Siberia. Type material ofDiscinella brastadi Poulsen, 1932 from North-East Greenland is re-studied and synonomised withDiscinella micans (Billings, 1871). Specimens from Siberia described asD. brastadi are re-assigned toMobergella hexactina n. sp., and specimens from Siberia described asMobergella radiolata Bengtson, 1968 are re-assigned toM. sibirica n. sp.Aktugaia triangula Mis-Sarzhevsky, 1976 from Kazakhstan is redescribed, and its relationship to other mobergellans is discussed.   相似文献   

3.
Pleistocene porcupine remains from China allocated toAtherurus sp.,Atherurus cf.macrourus andTrichys cf.fasciculata, and from Vietnam toAtherurus macrourus have been studied. These fossils have been compared with the type material of the PleistoceneA. karnuliensis Lydekker, 1886 from India and with the extant speciesA. macrourus (Linnaeus, 1758) andTrichys fasciculata (Shaw, 1801). As a result, all fossil specimens studied are allocated toA. karnuliensis.  相似文献   

4.
A fossil skull, Stw 53, from the Plio/Pleistocene of Sterkfontein, in South Africa, has been referred toHomo habilis Leakey, Napier, andTobias, 1964. Reappraisal of its putative hominine affinity reveals a closer resemblance toAustralopithecus africanus Dart, 1925. The skull, as reconstructed, is too small forH. habilis; with no indication of brain expansion overA. africanus; has a facial angle outside the hominine range, but identical with that ofA. africanus; and whose teeth are not elongated but display buccolingual expansion. Although it was found in the same strata (Member 5) as stone tools, there is no causal connection. It has been dated faunistically at 2–1.5 my BP, but due to an unconformity it is suggested that it could be older. In spite of its late date, Stw 53 shows no intermediate characters which could support a trend towardsH. habilis orA. robustus Broom, 1938. It may, therefore, represent a relict population ofA. africanus.  相似文献   

5.
Three species ofOcruranus Liu, 1979 are described from the Bastion Formation of North-East Greenland, of late Early Cambrian (middle Dyeran of North American usage) age, representing the youngest record of a genus originally described from the earliest Cambrian Meishucunian Stage of China. An accompanying species, tentatively assigned toXianfengella He &Yang, 1982, seems also to be present in South Australia in strata of late Early Cambrian (Botoman of Siberian usage) age, although also this genus was described originally from the Meishucunian.Ocruranus andXianfengella from China have been interpreted as possibly parts of coeloscleritophoran scleritomes, perhaps halkieriids, rather than individual molluscan shells. Their shell form is not typical of helcionelloids which otherwise dominate the Early Cambrian molluscan record, but conclusive evidence of affinity is not forthcoming from the Greenland records. New taxa:Ocruranus septentrionalis n. sp. andOcruranus tunuensis n. sp.   相似文献   

6.
Kenneth D. Laser 《Protoplasma》1974,80(1-3):279-283
Summary The plastids in sieve tube members of the stamen vascular bundles ofSorghum bicolor, fixed in glutaraldehyde with postfixation in osmium tetroxide, are of the P-type containing cuneate crystalloids of a proteinaceous nature surrounded by a double envelope. Secondary inclusions are present in these P-type plastids. P-type plastids inSorghum often remain intact in the mature sieve tube members.This work was supported by a grant from the Iowa Agricultural and Home Economics Experiment Station, Ames, U.S.A. Project No. 1740 toHarry T.Horner, Jr., andNels R.Lersten and Project No. 1914 toHarry T.Horner, Jr. of the Department of Botany and Plant Pathology, Iowa State University, Ames, U.S.A. This work was completed by the author as part of the Ph. D. dissertation research.  相似文献   

7.
Tillandsia carminea is a new, morphologically and ecologically distinct species, related toT. stricta Solander, which occurs in the Serra dos Orgaos near Teresopolis, Brazil. It has been taken forT. rosea Lindley, but new investigations have shown thatT. rosea is a synonym toT. stricta and thatT. carminea is a good and distinct species.
  相似文献   

8.
Summary E. coli KB (Benzer) differs from other common laboratory strains in possessing a glycyl sRNA synthetase with a 50 to 100 times elevated K m for glycine. The degree of charging of glycyl sRNA in this strain can be increased by supplementing the growth medium with glycine. The altered enzyme has been used as a marker by which to map its structural gene. Linkage analysis of recombinants from uninterrupted matings, and cotransduction (80%) of the synthetase withxyl, indicate that this gene is located betweenxyl andmalt, close toxyl, at min 69.5 on the map drawn byTaylor andThoman (1964).  相似文献   

9.
Specimens of the larger Neogene porcupines, generally allocated toHystrix primigenia (Wagner, 1848), from 17 localities are studied, and their taxonomic status is recon-sidered. Material from one of these localities has recently been described asHystrix depereti Sen, 2001. The diagnoses of both species are revised. Tooth size and crown height are considered diagnostic characters at the species level. As a resuit, specimens from eight localities are allocated toH. primigenia, from eight other localities toH. depereti, and from one locality toHystrix sp. indet. The level of specialisation of the cranial morphology of these fossil species is compared withH. refossa Gervais, 1852 and with extant species. Diagnostic characters ofH. aryanensis SEN, 2001 and ofH. zhengi van Weers & Zhang, 1999, are discussed.  相似文献   

10.
(1) The ability to produce cephalodia is usually a genus-specific character in lichens. (2)Lecidea shushanii Thoms., is a member of the genusTephromela, closely related toT. aglaea. It is not clear, whether or not the cephalodia of this taxon are true cephalodia or colonies of epiphytic cyanobacteria and whether or notLecidea shushanii is an independent species. (3)Lecidea dovrensis Nyl., is, in contrast to the traditional concept, not conspecific withLecidea alpestris Sommerf., but an earlier name forLecidea pallida Th. Fr. (4)Lecidea dovrensis is described in some detail. Chemically the species is characterized by the presence of isousnic acid (previously unknown in lecideoid lichens). It is restricted to areas north of the 60th parallel with an oceanic climate. (5) In connection with the attempt to clarify the taxonomic relationships ofLecidea dovrensis, figures of ascus apical structures of the following species are given (marked by an asterisk are genera where we found discrepancies with published data):Austrolecia antarctica, Catillaria chalybeia, Lecidea alpestris, L. caesioatra, L. limosa, Lecidoma demissum, Koerberiella wimmeriana, Micarea assimilata, M. crassipes, M. melaenida, M. prasina, Pilophorus robustus, Placodiella olivacea, Placolecis opaca, Porpidia trullisata, Protoblastenia rupestris, Psilolechia lucida, Psorula rufonigra, Squamarina gypsacea, Xanthopsorella texana. (6) Among crustaceous lichens we find no groups related toLecidea dovrensis. We supportTimal's concept of including this species in the genusPilophorus. Pilophorus, as well asLecidea dovrensis is characterized by the same ascus type, by a similar structure of thallus, cephalodia, paraphyses, and ascocarp (although there is no pseudopodetium developed inLecidea dovrensis), and the presence of isousnic acid. In addition, both taxa are restricted to cool oceanic climates and non-calciferous substrates. The following combination is proposed:Pilophorus dovrensis (Nyl.)Timdal, Hertel & Rambold, comb. nova. (7) The species of theLecidea alpestris-group form an independent genus, probably near toAustrolecia Hertel.
Frau Prof. Dr.Elisabeth Tschermak-Woess zu ihrem 70. Geburtstag gewidmet.  相似文献   

11.
A new species,Thomsonia sumawongii Bogner, is described from Thailand. Relationships toTh. napalensis and betweenThomsonia, Pseudodracontium andAmorphophallus are discussed.Allopythion hookeri Schott has to be eliminated as dubious.
  相似文献   

12.
The following species are described as new:Anthemis mazandaranica in N. and NW. Iran is allied toA. coelopoda; A. moghanica in NW. Iran is close toA. candidissima andA. sintenisii; A. atropatana also in NW. Iran is similar toA. hyalina; A. gracilis in W. Iran is close toA. plebeia; A. bushehrica in SW. Iran is similar toA. susiana; andA. rhodocentra in S. and E. Iran and in Pakistan is akin toA. austro-iranica, A. gayana, andA. kandaharica.
Anschrift des Herausgebers: Hofrat Univ.-Prof. Dr.Karl Heinz Rechinger, Beckgasse 22, A-1130 Wien, Österreich.  相似文献   

13.
W. P. Peters 《Genetica》1964,34(1):211-227
Krixousacorixa femorata (Guérin), a Mexican corixid, has symmetrical females and asymmetrical dextral or sinistral males. In studying the genetics of this species a sequence of experimental matings is described and the segregation ratios of the progenies analyzed. On the basis of these experiments a hypothesis, adequately explaining the data, is proposed.Exhypothesi the inheritance of the polymorphic characteristic of asymmetry depends upon the allelomorphic series of three genes,D, D 8, andd, of whichD (dextrality) is dominant toD s (sinistrality) which in turn is dominant tod (dextrality). The intermediate member of the series is lethal as a homozygote.A portion of the dissertation submitted in partial fulfillment of the requirements for the doctorate at Cambridge University. I wish to thank Professors SirRonald Fisher of Cambridge University andG. E. Hutchinson of Yale University for their kind help.  相似文献   

14.
A partial mandible with two molars intact was recovered between 1981 and 1984 from deposits of the Middle Pliocene at Tabarin, in Kenya. It has been described and assigned toAustralopithecus cf.afarensis Johanson, White, andCoppens, 1978, with the condition that if ‘A. afarensis’ is revised, then the attribution may change. The taxon ‘A. afarensis’ was found to be invalid and was revised. The smaller specimens of ‘A. afarensis,’ to which the Tabarin mandible was said to be similar, were redescribed asHomo antiquus Ferguson, 1984. Since the Tabarin mandible andH. antiquus are successive transients of the same gens and are allopatric, the Tabarin hominid population is described as an earlier chronosubspecies,Homo antiquus praegens ssp. n.  相似文献   

15.
Cynoglossopsis somaliensis H. Riedl, sp. nov., is described as a new species of the hitherto monotypic genusCynoglossopsis Brand which is closest related toCynoglossum L. but has to be included inBoraginoideae-Eritrichieae from the way the nutlets are attached to the gynobasis.
  相似文献   

16.
Veronica allahuekberensis A. Öztürk, spec. nova, probably endemic to the Allahuekber mountain in N.E. Anatolia, belongs toV. orientalis group of sectionVeronica and resemblesV. cuneifolia D. Don subsp.cuneifolia, endemic to S.W. Anatolia.
  相似文献   

17.
The serological investigations support the opinion ofJanchen (1942) to combine the generaBunias, Isatis, andSisymbrium in the tribeSisymbrieae; Cheiranthus, Erysimum, andMatthiola in the tribeHesperideae; andBrassica, Crambe, Sinapis, andSuccowia in the tribeBrassiceae. They further underline the central position of theSisymbrieae and the isolated position of theHeliophileae. In accordance withEigner (1973) theBrassiceae are placed closer to theSisymbrieae than inJanchen; the same holds for thePringleeae. No serological justification could be found to uniteArabis andBarbarea in the tribeArabideae, andAlyssum andLunaria in theAlysseae. From the antigen-systems used among the representatives ofJanchen's Lepidieae the generaLepidium andNeslia show remarkable correspondence both toCamelina andThlaspi, but not toCochlearia which appears distant fromCamelina andThlaspi also.
Teil 1/Part 1.  相似文献   

18.
Summary Two new species ofHeliotropium sect.Catimas DC. from the desert Registan in south-eastern Afghanistan are described, one of which,H. arenicolum Rech. f. et H.Riedl, is very closely related toH. Rechingeri H.Riedl (1967) and different from it only in the colour of the stems and the longer basal part of the style. The other one,H. leucocladum H.Riedl, belongs to a very natural group of xerophytic and halophytic species includingH. digynum (Forssk.)Aschers.,H. eremobium Bge.,H. Aucheri DC.,H. halame Boiss. etBuhse,H. Popovii H.Riedl andH. carmanicum Bge. Adaptations to the extremely dry habitat are discussed.  相似文献   

19.
Summary Adelocaryum anchusoides (Lindl.)Brand andA. capusii (Franch.)Brand are members of the genusLindelofia,A. Schlagintweitii Brand,A. erythraeum Brand,A. flexuosum Brand undA. malabaricum (C. B.Clarke)Brand are newly combined toCynoglossum, A. coelestinum (Lindl.)Brand is a species of subgenusEleutherostylum inCynoglossum in which genus it had already been placed byLindley.  相似文献   

20.
The taxonPraeanthropus africanus (Weinert, 1950), represented by the Garusi maxilla, is valid and reinstated. The morphological pattern of the Garusi maxilla is not that of a primitive hominid, but of a relatively generalized pongid. Since the apelike lectotype L.H.-4 and paralectotype A.L.200-1a ofAustralopithecus afarensis Johanson et al. 1978 are conspecific withP. africanus, and originate from the same formation, they are reassigned toPraeanthropus africanus.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号