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 31 毫秒
1.
Four species of cycad megasporophyll from the Lower Permian of Taiyuan, China, are described as Crossozamia chinensis (Zhu and Du) comb. nov., C. minor sp. nov., C. spadicia sp. nov. and C. cucullata comb. nov. together with the associated leaves Tianbaolinia circinalis gen. et sp. nov., Yuania chinensis Zhu and Du and Taeniopteris taiyuanensis Halle. An axis bearing megasporophylls in organic connection is described for the first time. Two possible evolutionary pathways from this structure to those of the female reproductive organs of extant cycads are proposed, involving either the reduction of the megasporophylls and their compaction on the axis, or the reduction of the “strobilus” axis. It is suggested that migration of cycads from North China to Europe might have occurred through transportation of their buoyant seeds by the palaeoceanic currents of the Tethys sea.  相似文献   

2.
马建  徐昭焕  张凯  张修国  邱玲 《菌物学报》2020,39(10):1846-1853
对江西省植物凋落物上的暗色丝孢真菌进行了调查研究,自植物枯枝上发现爱氏霉属3个新种——江西爱氏霉、井冈山爱氏霉和庐山爱氏霉,根据采集材料对其进行了详细的形态描述和显微拍照。爱氏霉属迄今已报道69个种。该属广布全球,多数种腐生于植物凋落物或沉水腐木上,未见作为植物病原菌引起植物病害的报道。  相似文献   

3.
From a total of 104 species and 1741 individuals of Isopoda, the material from DIVA-1 (DIVersity of the Atlantic benthos) contained 364 specimens belonging to Desmosomatidae Sars, 1897. They are represented by 10 genera and 27 species. Most species (93%) are new to science. Four species are described in this study (Eugerdella theodori sp. nov., Desmosoma renatae sp. nov., Torwolia tinbiene sp. nov. and Momedossa longipedis sp. nov.). A discussion of the genera Desmosoma Sars, 1864, Momedossa Hessler, 1970 and Torwolia Hessler, 1970 is presented.  相似文献   

4.
The leafless Vanilla species complex from the South-West Indian Ocean (SWIO) region has long been a taxonomic challenge, due to limited patterns of morphological differentiation and an absence of variation within chloroplast sequences. This complex includes seven known morphospecies: V. madagascariensis, V. bosseri, V. decaryana, and V. perrieri endemic to Madagascar, V. humblotii presumed as endemic to the Comoros Archipelago, but also present in Madagascar, V. roscheri from the East African coast, and V. phalaenopsis endemic to Seychelles. A previous population genetic study using microsatellite markers allowed us to distinguish, in addition to the five recognized Malagasy taxa, two other genetic clusters present in the East of the island. An integrative taxonomy approach was therefore conducted by combining microsatellite and morphological data used in the previous study with new data sets, and by adding ITS sequencing data, to validate the taxonomic level of these Malagasy genetic clusters and unravel phylogenetic relationships between SWIO species. As a result, based on phylogenetic, genotypic and morphological evidence, nine species were discriminated in the SWIO region, including seven in Madagascar, with two new eastern species. The leafless Vanilla group originated and diversified in Madagascar, from an ancestor of African descent, with three subsequent independent colonization events from Madagascar to the other territories of SWIO within the two main lineages (white versus yellow flower species). The new Malagasy species, V. allorgeae Andriamihaja & Pailler sp. nov., and V. atsinananensis Andriamihaja & Pailler sp. nov., are described and a new identification key is proposed.  相似文献   

5.
6.
7.
The living morphology, infraciliature and silverline system of 3 “well-known” marine scuticociliates, Uronemella filificum (Kahl, 1931) nov. gen., nov. comb. (formerly Uronema filificum Kahl, 1931), Pseudocohnilembus hargisi Evans & Thompson, 1964 and Cyclidium citrullus Cohn 1865 are reinvestigated and redescribed.

Based on the data obtained, we suggest an establishment of a new genus Uronemella. The diagnosis for the new taxon: thigmotactic Uronematidae with generally pear-shaped body and subequatorially positioned cytostome; apical plate dominant; oral apparatus Uronema-like, one-rowed membranelle 1 about as long as membranelle 2; paroral membrane extending anteriorly to about mid-level of membrane 2; one caudal cilium; in vivo exhibiting typical rotatory movement with help of a caudal-cilium-associated sticky thread; generally in marine habitats. According to this definition, three nominal species as new combinations are transferred into this genus: Uronemella binucleata (Song, 1993) nov. comb. (= Homalogastra binucleata Song, 1993), Uronemella filificum (Kahl, 1931) nov. comb. (= Uronema filificum Kahl, 1931) and Uronemella cymruensis (Pérez-Uz & Hope, 1997) nov. comb. (=Urocyclon cymruensis Pérez-Uz & Hope, 1997). For comparison with Uronemella, some other closely-related taxa are also briefly outlined in the present paper.  相似文献   


8.
9.
Four new species of Parameiropsis are described from Angola and Guinea Basins and the Arctic Laptev Sea. The male of Parameiropsis poseidonicus sp. n. differs from that of P. neptuni sp. n. and P. senckenbergi sp. n. in antennule segmentation, length of the proximal aesthetasc, length of the outermost seta of the antennary endopod, degree of reduction of the mouthparts, relative length of the inner spine of the basis of thoracopod 1, shape of the furca and body length. The female of P. amphitriteae sp. n. differs from previously described females of other species in the smaller exopod and endpod of thoracopod 1, reduced armature of thoracopods 1–6, length of the outer setae of exopods and endopods of thoracopods 2–4, and mandible exopod weakly developed and fused to the basis. Parameiropsis is redefined by the following autapomorphies: presence of aesthetasc on 3rd segment of female antennule; antenna strong, with endopod curved upwardly, and shape of the outermost (strongly ornamented) spine; triangular labrum; elongated corpus mandibularis, gnathobasis very long; basis of mandibular palp unarmed; elongated maxillule, with long and flexible setae on praecoxal arthrite; basis of the maxilla with strongly modified claw. To discuss the phylogenetic position of Parameiropsis, we revaluated the subfamilies of Ameiridae (viz. Ameirinae and Stenocopiinae) and the family Argestidae. Anoplosomella and Malacopsyllus revealed to be not closely related to Ameiridae and are transferred to Argestidae, sharing with other members of this family the morphology of the mandible gnathobasis, armature of maxilla and armature and length of the first segment of the antennule. Argestoides prehensilis does not show any of the characters that we consider autapomorphic for Argestidae. Instead, it shows many characters in common with several Ameiridae species. Parameiropsis does not have any character that could justify its inclusion within Ameiridae or even within Podogennonta. It also cannot be included satisfactorily within Argestidae nor Exanechentera. Therefore, we here propose a new family for Parameiropsis, with unclear relationships within Harpacticoida. After these taxonomic rearrangements, Ameiridae and Argestidae are considered monophyletic based on certain maxilla characters that we consider autapomorphic for each group. A key to the identification of the known species of Parameiropsis is added at the end.  相似文献   

10.
Cantharellus pleurotoides sp. nov. (Cantharellaceae, Cantharellales, Basidiomycota) is described from the Pakaraima Mountains of Guyana, occurring in rainforests dominated by ectomycorrhizal Dicymbe spp. (Caesalpiniaceae). This fungus is singular among Cantharellus species described worldwide in possessing a pleurotoid basidioma. Macromorphological, micromorphological, and habitat data are provided for the new species.  相似文献   

11.
The genus Chlamydomonas (including Chloromonas) is one of the largest green algal genera comprising more than 600 species. To initiate a comprehensive analysis of the phylogeny and systematics of the genus, we determined nuclear-encoded SSU rRNA sequences from 32 strains of Chlamydomonas, Chloromonas and Chlorogonium with emphasis on oogamous taxa and related strains, and incorporated these into global molecular phylogenetic analyses of 132 strains of Chlorophyceae. In addition, we studied the morphology and reproduction of oogamous and related strains by light microscopy. We recognize and designate 18 monophyletic lineages (clades) within the Chlorophyceae, 11 of which are confined to the CW (basal bodies displaced clockwise) subgroup. The majority of clades recognized within the Chlorophyceae do not correspond to any of the traditional classification systems, which are still largely based on the organization level. Strains assigned to Chlamydomonas and Chloromonas were found in seven different clades confirming the polyphyly of the two genera as presently conceived. To initiate the taxonomic revision of Chlamydomonas, C. reinhardtii is proposed as the conserved type of the genus. In consequence, species in clades other than the clade containing C. reinhardtii must be transferred to other genera, a process initiated in this contribution. The oogamous strains studied represent a monophyletic lineage, which is described as Oogamochlamys gen. nov. comprising three species (O. gigantea, O. zimbabwiensis and O. ettlii spec. nov.). The sister clade to Oogamochlamys consists of isogamous strains characterized by chloroplasts with incisions and is described as Lobochlamys gen. nov. with two species (L. culleus and L. segnis). Another clade is characterized by asteroid or perforated, parietal chloroplasts and contains the type species of Chloromonas (C. reticulata). Thus, the polyphyletic Chloromonas (traditionally defined as “Chlamydomonas without pyrenoids”) can be legitimized as a monophyletic genus by restriction to this clade and is here emended on the basis of chloroplast characters (the clade contains strains with or without pyrenoids thus rejecting the character “absence of pyrenoids”).  相似文献   

12.
Fruits of Restionaceae and seeds of Typhaceae are described from a latest Eocene–Oligocene mudstone underlying oil shales in a subsurface sequence near Rockhampton, coastal central Queensland. The Restionaceae fruits are unilocular and encase a single pendulous orthotropous seed with a structured micropylar cap, which may be tannin filled. These are allocated to Restiocarpum gen. nov., which has as its type Restiocarpum latericum sp. nov., and four other taxa described herein; Restiocarpum tesselatum sp. nov., Restiocarpum verrucatum sp. nov., Restiocarpum laeve sp. nov., and Restiocarpum fusiforme sp. nov. Typhaspermum cooksoniae gen. et sp. nov., which accommodates asymmetric claviform seeds, is interpreted as a member of the Typhaceae based on the presence of a lid-like operculum, bitegmic wall, and chalazal cavity.

Reconstruction of the source plant community emphasizes similarities to restiad swamps of present day Wallum (swamp heathland) vegetation which is extensively developed along the Queensland coast. Biogeographic implications for the Restionaceae and Typhaceae are discussed.  相似文献   


13.
Among living green algae assigned to the order Chlorococcales and order Zygnematales certain species develop resistant outer organic walls and/or cysts during their life cycles; as such they have the potential to become fossils. Based on morphology, comparison between living algae and microfossil remains are made with varying degrees of confidence, and a possible evolutionary pathway for certain chlorococcalean coenobial families is suggested. Twelve genera are reviewed from earliest to latest Triassic palynological assemblages from northwestern Australia; and the following taxa are described as new: Plaesiodictyon mosellanum ssp. symmetricum ssp. nov.; Plaesiodictyon mosellanum ssp. variabile ssp. nov.; Plaesiodictyon decussatus sp. nov.; Plaesiodictyon decussatus ssp. decussatus ssp. nov.; Plaesiodictyon decussatus ssp. tetracornuta ssp. nov.; Tetraporina protrusa sp. nov.; Crucigeniella? torques sp. nov.; and Paleoraphidia akestra gen. et sp. nov. (type). Their suggested natural affinities are useful in palaeoenvironmental interpretations of mostly freshwater or low-salinity habitats.  相似文献   

14.
Marine fish from several locations along the west coast of Norway were examined for leeches. Seven leech species were detected, Calliobdella nodulifera (Malm, 1863) from codfish, flatfish and a ray, Calliobdella lophii van Beneden & Hesse, 1863 from Lophius piscatorius L., Platybdella anarrhichae (Diesing, 1859) on Anarhichas lupus L., Platybdella quadrioculata Malm, 1863 on Symphodus melops (L.), Oceanobdella sp. on Zeugopterus punctatus (Bloch), Malmiana brunnea (Johansson, 1896) on Myoxocephalus scorpius (L.) and Malmiana bubali Srivastava, 1966 on Taurulus bubalis (Euphrasen). Calliobdella nodulifera infected unrelated hosts (euryxenic); the others appeared to be host specialists (oio- or stenoxenic). Details on the occurrence of Calliobdella nodulifera on Enchelyopus cimbrius (L.) during 1 year are given, which together with other observations suggest that its life cycle exceeds a year. A brief account on the morphology of “Platybdellaquadrioculata is provided, justifying its transfer to the genus Oceanobdella Caballero, 1956 as O. quadrioculata comb. nov. With the new additions, the Norwegian marine piscicolid fauna contain 12 species. At least ten additional species, known from adjoining areas, also probably occur along the Norwegian coast.  相似文献   

15.
In this contribution a new representative of the taxon Meidiama Marcus, 1946, Meidiama uruguayensis sp. nov. , from Uruguay, is described, as are six more new species, for which three new genera are proposed: Dreuxiola philippi gen. nov. sp. nov. , from the French subantarctic archipelago Kerguelen; Yorknia aprostatica gen. nov. sp. nov. ; Serrula byronensis gen. nov. sp. nov. ; Serrula maxillaria sp. nov. ; Serrula concharum sp. nov. ; and Serrula acuta sp. nov. , from eastern Australia and Tasmania. Arguments are presented to propose a new taxon to contain these new species, rather than include them in the Archimonocelididae Meixner, 1938 (of which Meidiama has been considered a member so far), as well as to remove the Calviriinae Martens & Curini‐Galletti from the Archimonocelididae to become a separate taxon Calviriidae. Possible autapomorphies for the three families are discussed. It is also concluded that, with the present state of our knowledge, no sound indications can be given about close relationships. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 759–773.  相似文献   

16.
Based on material from the fourth cruise of the RV Akademik Mstislav Keldysh and the MAR-ECO cruise of the RV G.O. Sars, 31 species of Ophiuroidea were identified from the section of the Mid-Atlantic Ridge between the Reykjanes Ridge and the Azores. The taxonomy of the group of genera with reduced arm comb and tentacle pores restricted only to the proximal arm segments is reviewed. It is suggested that the genera Homalophiura H.L. Clark, 1915, Ophiurolepis Matsumoto, 1915, Theodoria Fell, 1961 and Homophiura Paterson, 1985 should be regarded as synonyms of the genus Ophioplinthus Lyman, 1878. From examination of the type specimens, it is demonstrated that the six-armed species Ophiacantha anomala G.O. Sars, 1871 also includes five-armed specimens previously identified as the separate species Ophiacantha cuspidata Lyman, 1878. The latter taxon is considered here as the junior synonym of O. anomala. Previously mentioned 'deep-water populations of the common shallow water species Ophiacantha bidentata (Retzius, 1805)' represent a separate species, Ophiacantha fraterna Verrill, 1885, which is well distinguished by the shape of the spicules of the disk, narrow outer oral papilla and narrower tentacle scale as well as a hermaphroditic nature. Three new species, i.e. Ophioplinthus pseudotessellata sp. nov., Ophiocamax patersoni sp. nov. and Ophiophyllum nesisi sp. nov., are described.  相似文献   

17.
郭正堂 《植物研究》1987,7(3):85-112
本文报道中国韧革菌科(Stereaceae Pilat)真菌17种,隶属于柄革菌属(Stereopsis Reid)。韧革菌属(Stereum Hill:Persoon)和刷革菌属(Xylobolus Karsten)。其中有3个新种,1个新组合种和2个新记录种,它们是:厚盖柄革菌(Stereopsis crassipileata Z.T.Guo,sp.nov.)、细柄柄革菌(S.gracilistipitata Z.T.Guo,sp.nov.),假杯柄革菌(S.pseudocupulata Z.T.Guo,sp。nov.)、掌状柄革菌(S.craspedia(Fr.)Z.T.Guo,comb.nov.)、瓣裂柄革菌(S.hiscens(Berk. & Rav.)Reid)和蛋黄柄革菌(S.uitellina(Plowr.)Reid)。标本全部保藏于中国科学院微生物研究所真菌标本室(HMAS)。  相似文献   

18.
Protoperidiniacean dinoflagellate cysts have been recovered from Upper Miocene sediments of Hole 1095, ODP Leg 178, drilled to the west of the Antarctic Peninsula. These cysts make up virtually the entire dinoflagellate cyst assemblages, and three new species are formally described herein as Selenopemphix bothrion sp. nov., Selenopemphix kepion sp. nov. and Selenopemphix minys sp. nov., together with one informal taxon and two species attributed to published taxa. The occurrence of Late Miocene protoperidiniacean-dominated assemblages in the vicinity of the Antarctic continent is of special interest. Their presence may indicate the initiation of the Antarctic Circumpolar Current and increased nutrient supply within the Southern Ocean as the Antarctic Divergence became established. A comparison with several other protoperidiniacean dinoflagellate assemblages of similar age in other parts of the world provides some preliminary evidence for possible concomitant oceanographic change at this time.  相似文献   

19.
A new species of Baieroxylon, viz. B. cicatricum, is described from the Tiki Formation, Middle Gondwana, Upper Triassic of the South Rewa Gondwana Basin, Madhya Pradesh, India. The outer surface of the wood is marked with closely spaced “eye-shaped scars” and exhibits small, distinct central protuberances. These may probably represent vascular traces. The present described wood differs from all the known species of the genus by its characteristics stem scars. Dadoxylon graminovillae Zimmermann has been revised and a new combination is proposed, viz. Baieroxylon graminovillae (Zimmermann) Prasad et Lele comb. nov.  相似文献   

20.
Two new species of platanoid reproductive structure are described from the Bull Mountain locality in the Patapsco Formation (Potomac Group) of northeastern Maryland, USA. Pistillate inflorescences and infructescences (Platanocarpus elkneckensis sp. nov.) consist of flowers and fruits in sessile globose heads that are borne on an elongate axis. Individual pistillate flowers consist of five free carpels surrounded by prominent tepals. Staminate inflorescences, flowers and isolated stamens are assigned to Hamatia elkneckensis gen. et sp. nov. Staminate flowers are borne in a globose head with a small number of stamens (five?) per flower. Stamens consist of very short filaments, long anthers with strongly valvate dehiscence and an apically expanded connective. The connective expansion is frequently very well-developed, hook-like and extends down the ventral surface of the stamen. Anthers contain small, tricolporate, reticulate pollen. Association evidence, similarity of inflorescence structure and the occurrence of Hamatia-type pollen on flowers, carpels and fruits of Platanocarpus elkneckensis suggests that the staminate and pistillate material was produced by a single species of plant. The “Hamatia-plant” provides further evidence of pentamerous floral structure in mid-Cretaceous platanoids and documents the occurrence of unequivocal tricolporate pollen in the platanoid complex.  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