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.
A marine planktonic ciliate, belonging to the genus Askenasia Blochmann, 1895, is described with notes on its distribution and ecology. Specimens of this new species were collected from four coastal sites across the northern hemisphere. Samples were collected between March and December, from depths of 1-20 m. Relatively low (< 1 ml(-1)) densities were recorded from Atlantic and Pacific Oceans and North Sea coastal sites, whereas samples from the English Channel suggested that this species has the ability to form blooms. Specimens were protargol-stained, revealing the key features of the genus, including the diagnostic sub-equatorial kinety belt consisting of three unciliated monokinetids. However, the species is larger than other Askenasia with a single distinctive, rope-like, scalloped macronucleus. This species also appears to have an extra somatic kinety belt, which may be present but has not been observed in other Askenasia species. Based on size, kinety structure, kinety number, and macronuclear shape a new species has been established.  相似文献   

2.
Doroixys simplex n. sp. is described from material collected from a tunicate of the genus Ciona, collected on the North Pacific coast of Russia. This is the fourth species of the genus and the first for which the male has been found. The new species differs from congeners most noticeably in the absence of posterolateral processes from the rear margin of the dorsal cephalic shield. A key to species is provided.  相似文献   

3.
A new species of scorpion, Teuthraustes braziliensis sp. n. (Scorpiones, Chactidae), is described from the State of Amazonas, Brazil. This is the second species of the genus to be collected in the lowlands of South America, and the third record of a scorpion of the genus Teuthraustes to be recorded from Brazilian Amazonia. The total number of species of Teuthraustes is now raised to 21. The patterns of distribution of the genus are commented upon, and its geographical distribution is also enlarged.  相似文献   

4.
5.
Because of their role in causing schistosomiasis, flukes of the genus Schistosoma are the best known of all digeneans. The genus has traditionally been divided into four familiar species groups. Here we report on three poorly known species of Schistosoma, one of which, Schistosoma hippopotami, is known from the hippopotamus, one of which is provisionally identified as Schistosoma edwardiense, another hippo parasite, and a third that has not previously been described. All were collected from freshwater snails obtained from Lake Edward, western Uganda, the type locality for both known hippo schistosomes. The three different kinds of schistosome cercariae differ from one another in size, and all are readily differentiated by their long tail stems from the cercariae of human-infecting species. Furthermore, each was recovered from a different genus of snail host, Biomphalaria sudanica, Bulinus truncatus or Ceratophallus natalensis. Molecular analysis, based on 8350 bases of combined nuclear and mitochondrial DNA, groups these three long tail-stem cercariae into a well supported clade that does not associate with any of the recognised species groups. The placement of this clade, basal to all African species plus several Asian species, suggests that there has been an ancient association between Schistosoma and hippos. This new African Schistosoma clade advocates the need for further modification of the traditional species group-based classification. Two of the four species groups are paraphyletic. It also suggests that Schistosoma has been remarkably plastic with respect to adapting to snail hosts-three distantly related genera of planorbid snails have been exploited by worms within a single clade. Finally, it adds a new layer of complexity to deciphering the origins of Schistosoma, often considered to be African but recently challenged as being Asian. In the late Cenozoic the distribution of hippo species straddled both Africa and Asia and they may have provided a means for the introduction of blood flukes to Africa.  相似文献   

6.
拟口蘑属一新种   总被引:1,自引:0,他引:1  
本文报道产自吉林省舒兰县的拟口蘑属(Tricholomopsis)一新种:舒兰拟口蘑(T.shulanensis X.He)。文中还对作为该属模式种的赭红拟口蘑(T.rutilans)的侧囊体存在与否阐述了意见。  相似文献   

7.
8.
Summary A new genus of the Gymnoascaceae is described and illustrated. A single species,Petalosporus nodulosus, is described. Four isolates representing this new species were isolated from dung in India and California. Morphological development and other diagnostic characteristics are given. The new genus is characterized by the formation of a discrete but often fragmentary ascocarp the peridium of which undergoes partial disarticulation at maturity. At least some of the peridial hyphae have thick walls and are enlarged at septal nodes, and these septa are also the points of disarticulation. A primary generic character is the floral-shaped pattern in which ascospores are found.  相似文献   

9.
10.
A new species of the genus Laubieriopsis Petersen, 2000 is described based on 28 specimens collected in the north-east part of the North Sea. It is characterized by fixed number of chaetigers (22), paired genital papillae, bidentate neurochaeta of chaetigers 1-4, the absence of acicular chaetae on chaetigers 5-21 and, on the last chaetiger, one acicular and three capillary chaetae enlarged and directed backward. The present study brings the number of known species of Laubieriopsis to five and the number of Northeast Atlantic species of this genus to two.  相似文献   

11.
Abstract:  A new species of the genus Epiphaxum (family Lithotelestidae) is described and illustrated in detail, and compared to other species. Epiphaxum arbuscula sp. nov. has been collected from Upper Eocene (Priabonian), Upper Oligocene (Chattian) and Lower Miocene (Upper Burdigalian) deposits of the Aquitaine Basin, south-west France. Epiphaxum is a poorly documented genus but its fossil record extends back to the Late Cretaceous; it was previously known only from the Paleocene (Danian). Epiphaxum arbuscula differs from all others species of the genus in the form of its colony. In contrast to the creeping colonies of previously known species, it has branched colonies. It is very common at one Upper Oligocene outcrop from which an assemblage with submarine cave remains has been described. A close relationship between the three extant species (two from the Caribbean Sea and one from the Indo-West Pacific region) and the Paleogene species is also noted. These constitute a group that has not undergone any important morphological changes for the last 65 million years.  相似文献   

12.
喜雨草,湖南珍稀特有植物,属唇形科单型属喜雨草属,自1918年8月韩马迪在湖南西南部武冈云山采到模式标本,并于1936年作为一个新属、新种发表后,其踪迹消失全无。该次报道为喜雨草被发现近100年后,在湖南宁远、通道、道县、新宁被重新发现。根据采集的标本和拍摄的照片,更正修改和补充了原形态描述,重新确定了该种花萼为3/2式,花冠颜色为白色。  相似文献   

13.
原端齿鲨在中国的发现   总被引:2,自引:0,他引:2  
原端齿鲨 (Protacrodus) 以往只见于德国和美国的上泥盆统中,这次从苏北油田钻孔岩样中发现的一枚牙齿具有该属之主要形态特征,经比较,确定其为—新种——Protacrodus orientalis sp. nov. 此新种在齿冠各齿头的嵴突数、齿冠的高宽比以及齿根表面血管神经通孔的排列形式等方面均有别于欧美的已定种.  相似文献   

14.
谭瑞成  鲁素玲 《昆虫学报》1996,39(4):434-436
中国单头螨属一新种(蜱螨亚纲:叶螨科)谭瑞成,鲁素玲(湖南省林业科学研究所长沙410004)(新疆石河子农学院新疆832003)单头螨属AplonobiaWOmersley,1940前足体背毛3对,后半体背毛10对,全部或部分背毛着生在明显结节L,背...  相似文献   

15.
Lowiaceae, a family of the Zingiberales, comprise 11 species in the single genus Orchidantha. Here we present the first report on the pollination of Lowiaceae and describe a new system of dung-beetle pollination from Sarawak, Borneo. Orchidantha inouei has a zygomorphic flower located just above the ground. Observations revealed that the plant is visited frequently and is pollinated by scarabaeid dung beetles, mainly members of the genus Onthophagus. All four species of Onthophagus collected on O. inouei have also been caught using traps baited with dung or carrion in Borneo. Onthophagus was presumably attracted to the dung-like odor of the flower. Pollination of O. inouei is different from other examples of beetle pollination in that its flower provides neither reward nor protected space. Dung beetles are excellent at following a particular dung scent. Orchidantha is the only genus that includes species lacking floral nectar. It is interesting that this deception pollination using dung beetles was found in Zingiberales, in which all known species have mutual and specialized relationships with their long-distance, but costly, pollinators-bees, birds, and bats.  相似文献   

16.
Scalithrium gen. n. (Cestoda, Tetraphyllidea) is proposed with Scalithrium minimum (Van Beneden, 1850) n. comb., parasite of Dasyatis pastinaca (Elasmobranchii, Dasyatidae) as type-species. The new genus Scalithrium (Tetraphyllidea, Phyllobothriidae, Rhinebothriinae) is erected for several species previously included in the genus Rhinebothrium. These species have a scolex with four bothridia, the distal surface of which is divided by transverse septa in a single row of loculi. Scalithrium minimum (Van Beneden, 1850) n. comb. is redescribed from specimens collected from the type-host Dasyatis pastinaca in Tunisia and becomes the type-species of the new genus. After Braun (1900) Echeneibothrium variabile Van Beneden, 1850 is considered as type-species of the genus Echeneibothrium. Species of Rhinebothriinae to be transferred into the genus Scalithrium are discussed and a key is proposed for the eight species.  相似文献   

17.
Bennett DJ 《ZooKeys》2011,(141):65-70
A distinctive new species of the crabronine wasp genus Quexua Pate is described and figured from a single male collected from lowland Amazonian rain forest in southeastern Peru. Quexua cicrasp. n. is the only species in the genus known with a sessile metasoma.  相似文献   

18.
M. King 《Genetica》1984,64(2):101-114
Karyotypic data are presented for six additional species from the genus Gehyra collected in Australia, New Guinea and Fiji. C and G-banding of three of the very diverse species which all share the ancestral 2n=44 karyotype, further strengthens the phylogenetic model for the evolution of this complex. With 19 Australian species and chromosome races of Gehyra now karyotyped, it has been possible to evaluate the mode of chromosomal evolution and the role that chromosome change has played in speciation in this genus. It is clear that speciation in certain karyomorph groups has occurred allopatrically, without any gross chromosomal changes. However, in the numerous chromosome races and species which have been involved in colonizing radiations, chromosomal rearrangements have been intricately associated with the speciation process.  相似文献   

19.
Keraunea Cheek & Simão‐Bianchini gen. nov. (Convolvulaceae) from Brazil is described and illustrated as the third known neuropeltoid genus. It appears allied to the Old World genera of Neuropeltis Wall and Neuropeltopsis Ooststr. in having wind‐dispersed fruits not by enlarged sepals, but subtended by an enlarged papery bract to which the pedicel is adnate, and flowers in which the bracteoles are absent or usually very inconspicuous. Keraunea brasiliensis, the single species thus far known, is here assessed as ‘Endangered’.  相似文献   

20.
With a careful study of the external forms and the cuticles of the fossil leaves, a species of Thinafeldia, which was collected from Langdai, Liuzhi County of Guizhou Province, has been identified as T. rhomboidalis Ett. Compare with two other species T. alethopteroides Sze and T. laxa Sze found in Yanchang Formation, Northern Shaanxi, which showed very similar external form (no cuticle structure) of T. rhomboidalis, therefore it is appropriate to clarify them as T. rhomboidalis. As for the genus Thinnfeldia, based on the study of Chinese material, the author set forth her opinion that Thianfeldia should be a separate genus instead of merging into the genus of Pachypteris as has been clarified by many palaeobotanists.  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