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1.
Four hundred Gyrodactylus species have been formally described, but the estimated number of species in this fish ectoparasite genus of Monogenean Platyhelminthes is more than 20,000. The unusually high species richness has lead to the hypotheses of speciation and adaptive radiation via host switching. These hypotheses were tested by reconstructing a molecular phylogeny for the subgenus G. (Limnonephrotus) which is a group of freshwater parasites, including five species infecting wild and farmed salmonids. The highly variable ITS1 and ITS2 segments and the conservative 5.8S ribosomal gene were sequenced in 22 species plus two species representing the subgenus G. (Paranephrotus) as an outgroup. The phylogeny was compared with host systematics: the species were collected from six fish families (Cyprinidae, Salmonidae, Percidae, Esocidae, Gasterosteidae, and Gobitidae). The phylogenetic analysis demonstrated that G. (Limnonephrotus) is a monophyletic group that was originally hosted by cyprinids. The speciation has occurred in two episodes, the older one manifested in genetic distances 25-33% (4-6 Myr BP). The latter speciation burst occurred in one clade only, perhaps one million years ago. This clade has been morphologically identified as a wageneri species group. It is a monophyletic group of 18 species [studied here] and contains all five salmonid parasites, but also parasites, on cyprinids, percids, esocids, and gasterosteids. In G. (Limnonephrotus), eight host switches crossing the host family barrier were observed, and at least three of them were followed by repetitive speciation. Seven host-switch events were statistically confirmed by bootstrapping. The suggested model of speciation by host switch was accepted, and interestingly the adaptive radiation seems to be a consequence of host switch to a new family (key innovation model). The molecular and ecological evolution rate of Gyrodactylus parasites is manyfold in comparison to host species, and the phylogenies are largely independent and disconnected.  相似文献   

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3.
In the littoral of the lakes Titisee (FRG) and Neusiedler See (Austria) and in a backwater near Stockerau (Austria) two periphytic unicellular blue-green algae with rod-like cells have been found. They were formerly thought to be members of the exosporine generaChamaesiphon orCyanophanon. Now the alga from Titisee was studied in culture, particularly with reference to cell division, reproduction and ultrastructural cytology. Similarities with the genusSynechococcus are evident, but there is a small mucilaginous disc at the basis of the cells. Because of differences between this and all other known genera of unicellular blue-green algae, a new genus,Geitleribactron, with two species,G. periphyticum (= type species) andG. subaequale, is described.  相似文献   

4.
记述中国太宇谷蛾属Gerontha Walker10种,其中有4新种:拟华太宇谷蛾G.similihoenei sp.nov.,喙太宇谷蛾G.rostriformis sp.nov.,梯缘太宇谷蛾G.trapezia sp.nov.,褶太宇谷蛾G.rugulosa sp.nov.和3新纪录种:暹罗太宇谷蛾G.siamensis Moriuti,1989(图7,17~18)、清迈太宇谷蛾G.nawapuriensis Moriuti,1989(图8,19)、钻太宇谷蛾G.borea Moriuti,1977(图9,20).首次发现和报道了弯茎太宇谷蛾Gerontha flexura Huang et al .(图6,15-16)和暹罗太宇谷蛾G.siamensis Moriuti的雌性个体.文中给出了所有中国种的检索表.研究标本保存于南开大学生命科学学院昆虫标本室.  相似文献   

5.
We report five different colour morphs of the hesionid polychaete genus Gyptis co-occurring in a small area in shallow water under Edithburgh jetty, South Australia. The five morphs cannot be separated using standard morphological features, but phylogenetic analyses of sequence data (COI and ITS1) unequivocally show that three species are present, introduced as Gyptis simpsonorum , new species, G. paucilineata , new species and G. polymorpha , new species. Gyptis simpsonorum has a speckled pigmentation pattern and G. paucilineata a few transverse lines on specific segments. Gyptis polymorpha is polymorphic with three different, distinct pigmentation patterns, either as dense transverse lines, as a thin longitudinal, mid-dorsal line, or as an uniformly dark dorsum. The speckled pigmentation likely represents the plesiomorphic condition, and G. propinqua is the closest known relative to these new species.  相似文献   

6.
《Journal of bryology》2013,35(3):165-168
Abstract

The genus Gottschelia Grolle is reported as new to mainland China, from Yunnan Province. Previously G. schizopleura (Spruce) Grolle was the only known Chinese species, reported from Taiwan. However, two further species have recently been found in the Gaoligong Shan range, Yunnan Province, G. patoniae Grolle, Schill & D.G. Long, previously known from the East Himalaya of Nepal and India (Sikkim) and G. grollei D.G. Long & Váňa, described here as a new species endemic to China, the fourth known species in the genus. The differences between the three Chinese species are enumerated with notes on distribution and ecology.  相似文献   

7.
The living fossil Ginkgo, a relict of a once dominant gymnosperm, existed and flourished early in the Mesozoic, but only a vague outline of its evolutionary history in the Tertiary has been unveiled. Here we describe a new species, Ginkgo jiayinensis sp. nov., from the Wuyun Formation of Jiayin, China, which is another well-established Tertiary species based on leaf fossils besides G. adiantoides. The most remarkable feature of the new species is the amphistomatic leaves, likely representing a distinct evolutionary line of the genus in this time interval. Ginkgo jiayinensis is similar to the co-occurring G. adiantoides and extant G. biloba in the lower cuticle, but the two latter species clearly differ in having hypostomatic leaves. Ginkgo biloba is used as the nearest living equivalent (NLE) species for both G. adiantoides and G. jiayinensis in reconstructing paleo-CO(2), as it has been used for other fossil species with either hypostomatic or amphistomatic leaves. The two Tertiary species are almost identical in stomatal index in abaxial cuticles (8.4 and 8.5, respectively), showing no strong differences in response to atmospheric CO(2). Amphistomatic G. jiayinensis would therefore have used a different ecological strategy from that of G. adiantoides of the same bed.  相似文献   

8.
记述了中国斑腿蝗科Catantopidae 1新纪录属拟庚蝗属Genimenoides Henry,1934,1新种条纹拟庚蝗Genimenoides vittatum sp.nov.;庚蝗属Genimen Bolivar,19182新种版纳庚蝗Genimen bannanum sp.nov.和郑氏庚蝗Genimen zhengi sp.nov.。编写了拟庚蝗属已知种检索表和庚蝗属中国种检索表。模式标本保存于大理学院生命科学与化学学院。  相似文献   

9.
楔桥弯藻属(Gomphocymbella)是由Mueller在1905年建立的,它兼有桥弯藻属和异极藻属的双重特性。虽然对它的系统发育及分类问题仍在讨论之中,但一般把它归于异极藻科中。它较为罕见,至今报道的种类仅有10个左右。在我国至今只报道有一个种。近几年来,对湖北省硅藻类中的异极藻科(Gomphomenaceae)进行了分类学研究,发现有3个楔桥弯藻属的种类,其中2个为新种类:疏纹楔桥弯藻(Gomphocymbella laxistria Shi et N.Li)和不对称楔桥弯藻(G.asymmetrica Shi et N.Li);另一个种为我国首次报道的新记录:波润楔桥弯藻(G.brunii(Fricke)O.Mailer)。  相似文献   

10.
锥羽蛾属Gillmeria全世界已记录13种,除G.omissalis(Fletcher)分布于澳大利亚外,其余12种均分布在全北区,而G.pallidactyla(Haworth)在巴西也有记录.我国原记录有4种,本文记述8种,包括3新种和中国1新纪录种.新种为:楔锥羽蛾G cuneiformis sp.nov.,点斑锥羽蛾G.fuscata sp.nov.和佛坪锥羽蛾G.fopingensis sp.nov.新纪录种环锥羽蛾G.ochrodactyla(Denis &Schiffermüller).文中给出了中国锥羽蛾属的分种检索表,并提供了成虫图和外生殖器特征图.研究标本及模式标本分别保存在南开大学生物系昆虫标本室和中国科学院动物研究所昆虫标本馆.  相似文献   

11.
Two sibling species of mole crickets of the Gryllotalpa gryllotalpa group inhabit Israel. Both are described as new species based on differences in their morphology, acoustic behaviour, chromosome number, cuticular hydrocarbon pattern and habitats. The species with males having 2n = 23 chromosomes, described in the past as the 'Dead Sea race', is designated as G. marismortui sp.n. It is an endangered species. In morphology and chromosome number it is similar to G. cossyrensis Bacetti & Capra from Italy, but differs in the composition of cuticular hydrocarbons. Gryllotalpa marismortui occurs in a limited geographical area along the shore of the Dead Sea. Another species, with 2n = 19 chromosomes, is described as G. tali sp.n. and is found throughout Israel. The calling songs of the males of the new species differ markedly. Females of the respective chromosomal numbers discriminate in favour of the homospecific call. Their habitats are strikingly different: G. marismortui lives in hypersaline soil along the Dead Sea shore (total chloride 187.25 meq %), G. tali inhabits freshwater soil (9.31 meq %). The distribution of the twelve known sibling species and one chromosomal race (not yet described) of the G. gryllotalpa group from Europe and the eastern Mediterranean is summarized. The zoogeography and phylogeny of the group are discussed.  相似文献   

12.
Four Gyrodactylus species parasitising four closely related gobiid species in European coastal waters were studied and compared with G. arcuatus Bychowsky sensu Bychowsky & Poljansky (1953) from Gasterosteus aculatus . These were G. gondae n. sp. from Pomatoschistus minutus and P. lozanoi , G. flavescensis n. sp. from Gobiusculus flavescens , G. arcuatoides n. sp. from P. minutus and G. branchialis n. sp. from P. microps. Combined molecular and morphological analyses, as well as morphometric and statistical methods, were used. The ssrRNA V4 region and the complete ITS rDNA region were sequenced. Genetically the four new species are clearly distinct from G. arcuatus . From a morphological point of view, the haptoral hard parts of G. gondae n. sp., G. flavescensis n. sp. and G. arcuatoides n. sp. are related to those of G. arcuatus, while these parts of G. branchialis n. sp. are different, but related to those of G. quadratidigitus Longshaw, Pursglove & Shinn, 2003. For the latter two species, a new species group is formed. The V4 and ITS sequence analyses, however, indicate a close relationship between G. branchialis and the three G. arcuatus-like species.  相似文献   

13.
Gossypium arboreum L. and G. herbaceum L. are the diploid species of cultivated cotton. Little is known regarding the time and place of domestication of either species. Because G. arboreum is known only as a cultigen, others have proposed that it arose from domesticated G. herbaceum during the more than 5,000-year history of Old World cotton cultivation, with wild G. herbaceum subsp. africanum (Watt) Mauer as the putative ancestor of both species. An alternative hypothesis is that the two species have independent origins from progenitors that diverged prior to domestication. The relative merits of these opposing hypotheses were evaluated using data derived from starch gel electrophoresis of enzymes. One hundred and three accessions of G. arboreum and 31 accessions of G. herbaceum were examined for allelic variation at 40 allozyme loci. All measures of genetic variability demonstrated that G. arboreum contains greater diversity than G. herbaceum, although both species have relatively low levels of allozyme variation. In contrast to expectations based on morphology and other chemical data sets, the two species are highly differentiated with respect to allozyme composition. Gossypium arboreum and G. herbaceum each contain a large number of unique alleles and are fixed or nearly fixed for alternate alleles at 8 loci. Five allozyme loci have alleles that are rare in one of the two species but common in the other. Based on restricted occurrence of these alleles to areas with a long history of sympatric cultivation and the geographic distribution of a null allele, we suggest that a significant portion of the allelic diversity in both species results from historical, bidirectional interspecific introgression. The interspecific genetic identity estimate (0.74) is markedly lower than for documented progenitor-derivative and crop-ancestor species pairs. Based on these data, as well as previous cytogenetic data and the observation of F2 breakdown in interspecific crosses, we suggest that cultivated G. arboreum and G. herbaceum were independently domesticated from divergent ancestors.  相似文献   

14.
The systematics and distribution of the cirrate octopod genus Grimpoteuthis in the north-east Atlantic are reviewed. Three new species are described and Grimpoteuthis wuelkeri (Grimpe, 1920) is redescribed. A new generic diagnosis is proposed. Five species of Grimpoteuthis are recognized in the north-east Atlantic. The type species, G. umbellata (Fisher, 1883) is known only from the type specimen, which is in such poor condition that comparison with recently captured material was not possible. G. wuelkeri is a large, slope species, caught between 1600 m and 2200 m in the north-east and north-west Atlantic. Of the three new species, both G. boylei and G. challengeri are large abyssal species. G. boylei is found in the north-east Atlantic at the Porcupine Abyssal Plain (PAP) and the Madeira Abyssal Plain and may be found at abyssal depths throughout the north-east Atlantic. G. challengeri is known from the PAP, with a single specimen from the north-west Atlantic. G. discoveryi is a small, lower slope and abyssal species found in the north-east Atlantic. The Grimpoteuthis species can be separated based on shell form, presence of a radula and posterior salivary glands, arrangement of suckers and cirri and gill morphology. Two species, G. megaptera Verrill and G. plena Verrill, have been described from the north-west Atlantic, but the types are either lost ( G. megaptera ) or in poor condition ( G. plena ), hindering comparisons. Material examined from the north-west Atlantic included G. wuelkeri , G. challengeri and at least two other species.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society , 2003, 139 , 93−127.  相似文献   

15.
The species of Goniothalamus (Annonaceae) occurring in Peninsular Malaysia and Singapore are revised, updating the previous taxonomic treatment by James Sinclair, published in 1955. A total of 18 species is recognized, including a new species, G. tomentosus . Collections referrable to G. tomentosus were previously determined as ' G. marcanii '; examination of the types of G. marcanii reveals that the two taxa are not conspecific, however, and a new name is accordingly validated here. Goniothalamus tomentosus has closest affinities with the Javan/Sumatran species G. costulatus . Other important nomenclatural changes include the reduction of G. umbrosus to synonymy with G. tapis .  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142 , 321−339.  相似文献   

16.
The present study brings together survey data from collection in several localities in the Brazilian Amazon and specimens from the Entomological Collection of Museu Paraense Emílio Goeldi (MPEG-Belém). The flies were collected over organic decomposing matter (bananas and bovine meat) baits. The genus Odontoloxozus Enderlein, with the species Odontoloxozus peruanus Hennig, is recorded from Brazil for the first time. The species Glyphidops (Glyphidops) flavipes (Widemann), G. (Oncopsia) flavifrons (Bigot), G.(O.) durus (Cresson) and G. (O.) dipsar (Hennig) are new occurrences for Brazil. The species G. (O.)carrerai Aczél and N. plurivittatus Bigot are new occurrences from Brazilian Amazon. A key to Brazilian Amazon species is provided.  相似文献   

17.
甘肃白龙江中上游流域的黏菌   总被引:1,自引:1,他引:0  
本文报道了采自甘肃白龙江中上游流域的黏菌52种,其中紫高杯菌Craterium paraguayenese、山地双皮菌Diderma montanum和双被绒泡菌Physarum bitectum为中国新记录种,另有34种为甘肃新记录种。  相似文献   

18.
Compared to related genera, this new flea genus is characterized by the absence, or presence of very few, bristles on the external surface of femur I and especially by the morphology of the apex of sternite IX in the male, which is hyaline and lacks spiniform bristles. The two new species, G. bunomydis and G. margaretamydis, are distinguished from each other by the structure of the genitalia, and the presence of numerous erect bristles on the thorax and abdominal tergites of the latter species. Both of these new species parasitize murine rodents that are endemic to Sulawesi; G. bunomydis was collected mainly from Bunomys chrysocomus and G. margaretamydis only from Margaretamys parvus.  相似文献   

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20.
重新厘定后,步氏羚羊(Gazellablacki)的主要特征是个体中等大小,脑颅部宽而短,枕面向后突出不明显,枕髁与枕面处在同一平面中,基枕面平,呈方形,具宽浅而长的中纵沟;角心纤细,短而直,从角基向角项方向迅速变尖,基部横切面为次圆形;颊齿高冠,前臼齿列短和p4有封闭的前内谷等。它出现在我国山西上上新统的地层中。依据头骨和颊齿的性状,它可能是现生种G.picticaudata和G.gutturosa的祖先类型。  相似文献   

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