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1.
A new diatom genus, Brevilinea gen. nov., is described from an acidic freshwater lake situated on the Atlantic Coastal Plain of North Carolina, USA. The type for the genus, Brevilinea pocosinensis sp. nov., differs from other diatoms by the presence of a unique and reduced raphe that is restricted to the central portion of the valve. The new taxon has large and distinctive areolae that also serve to separate it from existing genera. The taxonomic placement of the new organism relative to other diatoms possessing a reduced raphe is discussed. Although Brevilinea may eventually be placed into a new family, given the current dynamic state of diatom systematics, it is premature to do so at this time.  相似文献   

2.
The morphology and ontogenetic allometric trends of a rare diatom Fragilaria heidenii Østrup and the morphologically related Staurosira tabellaria (W. Smith) Leuduger-Fortmorel were compared using conventional and semilandmark-based geometric morphometric analyses. Fragilaria heidenii was studied in detail by light and electron microscopy using type material and recent samples from Lake Ladoga and Lake Ilmen (north-western Russia). The taxon is transferred into the genus Staurosira Ehrenberg as Staurosira inflata comb. nov. on the basis of its valve morphology. This taxon is characterized by the absence of rimoportulae, lack of perforated copulae, spines located on the interstriae, internal vola occlusion in the areolae and the features of the areolae and apical pore fields. Conventional morphometric analysis showed considerable overlapping of S. inflata and S. tabellaria in their frustule characteristics such as length, width, length-to-width ratio and striae density. Moreover, at later stages of the vegetative life cycle, S. inflata has a tendency to resemble S. tabellaria by its valve outline that makes it difficult to separate these two taxa. The geometric morphometric analysis revealed two shape groups corresponding to S. inflata and S. tabellaria that were separated by a clear gap. Semilandmarks representing shape of the middle part of the valve were primarily responsible for discrimination between species. Apart from differences in valve shapes, S. inflata and S. tabellaria also differed significantly in their ontogenetic allometric trajectories. Overall, our results demonstrate that the semilandmark-based geometric morphometrics is sensitive enough to distinguish species by their outlines, when traditional morphometric parameters are not able to discriminate them with confidence.  相似文献   

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The canal-bearing diatom genus Nagumoea, described based on only morphological evidence, was tentatively assigned to the order Bacillariales, although its phylogenetic position remained unclear. Because three isolates of Nagumoea (SK002, SK024 and SK053) were successfully established from Japanese coasts, we performed their morphological observations and molecular phylogenetic analyses to discuss the phylogeny and taxonomic position of this genus. Strains SK002 and SK024 were identified as Nagumoea africana, whereas SK053 conformed with Nagumoea serrata. There was high interspecific divergence between N. africana and N. serrata in the rbcL sequences (8.03–8.17%), indicating their distinctness. Furthermore, intraspecific variations were detected within N. africana (2.35%) in the rbcL, implying its cryptic diversity. The maximum likelihood and Bayesian phylogenetic trees inferred from the plastid rbcL, psbC and nuclear 18S rDNA genes recovered Nagumoea as monophyletic with strong statistical support and embedded within an unresolved, poorly supported lineage containing Achnanthes, Craspedostauros, Staurotropis and Undatella in the canal-bearing order Bacillariales (= the family Bacillariaceae). Although the constrained tree based on the monophyly of Nagumoea and the other canal-bearing clade (Surirellales and Rhopalodiales) was statistically rejected by the topology tests, the phylogenetic position of Nagumoea with other Bacillarialean members remains equivocal. The possession of two plastids positioned fore and aft, observed in the present study, and lack of keel, typical of the Bacillariales, indicate the possibility of Nagumoea being part of the ingroup of the Bacillariales or its closely related outgroup.  相似文献   

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Dolichodorus grandaspicatus n. sp., collected from soil about roots of a red maple (Acer rubrum L.) in a creek bottom near Ludwig. Johnson County, Arkansas, is described. It differs from two closely related species, D. marylandicus and D. heterocephalus, by the longer spike on the female tail, the lenght of the female tail, and the shape of the extrudable portion of the gubernaculum of the males. It further differs from D. marylandicus by having heavily sclerotized accessory pieces of the vuvla and from D. heterocephalus by having a shorter stylet.  相似文献   

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The following three new species are illustrated and described from Fiji: Triaenodes rebellus Eriksson & Johanson, sp. n., Triaenodes oscitus Müller & Johanson, sp. n., and Triaenodes forcipatus Puranen Li & Johanson, sp. n. All species are endemic to Viti Levu. A key to the male Triaenodes species of Fiji is provided. With this report, the number of Triaenodes species known from Fiji is doubled.  相似文献   

9.
A new species, Homidia pseudoformosana from Korea is described in the present paper. The new species is characterized by labral papillae, ciliated labial seta L1 and dorsal chaetotaxy of abdominal segment IV. The detailed differences between similar Homidia species are provided.  相似文献   

10.
A new, monotypic genus and species in the subfamily Mesorhabditinae is described and illustrated. The primary character which separates the species and genus from all others in the Rhabditidae is a lip region with six set-off and well-separated liplets of two alternating shapes. Other diagnostic characters are transverse and fine longitudinal body striations, cuticular micropores, a prismatic prostom, well-developed esophageal collar, and three denticles on each metarhabdion. Males have a peloderan, open bursa bearing two pre- and seven post-anal bursal papillae, fused spicules over 50 μm long, and paired diverticulate cement glands associated with the vas deferens.  相似文献   

11.
A new species of Pararotylenchus Baldwin &Bell, 1981 from the Pacific coastal area of California is described. Numerous females and juveniles were recovered, but no males were found. Pararotylenchus belli n.sp. is most similar to P. sphaerocephalus, but females of P. belli are shorter and have a shorter stylet and a hemispherical tail. Specimens from a cereal field in South Dakota were identified as P. colocaudatus.  相似文献   

12.
Pratylenchoides sheri n. sp., a bisexual species from the Pacific coastal area of California, is described and illustrated. Its most distinctive characters are the esophageal glands slightly overlapping the intestine dorsally, the large ventrally slanting esophago-intestinal valve, the lack of labial sectors in the first lip annule, the presence of males, and apparently functional spermatheca. Pratylenchoides sheri is morphologically similar to P. magnicauda, but differs in length and labial conformation, its more anterior vulva, and the presence of males. Relationships of head and esophagus gland lobe characters of P. sheri are compared to other Pratylenchoides species.  相似文献   

13.
A new Nipergasilus species is described from the gills of the grey mullet Valamugil cunnesius from several localities in India and Pakistan. The new species is closely related to Nipergasilus bora (Yamaguti, 1939) which is also recorded here on three species of grey mullet. The genus Nipergasilus is redefined in order to accommodate the second species.  相似文献   

14.
A new species. Quinisulcius solani, is described and illustrated from specimens on Solanum tuberosum from Murree Hills, Pakistan. Q. solani n.sp. differs from its closest relative, Q. acutus (Allen, 1955) Siddiqi, 1971, by its spiral to open ''C'' shaped body and stylet length of 19 μn, vs. 17 μm in Q. acutus. In Q. acutus the stylet knobs project anteriorly but slope posteriorly in Q. solani n.sp. Tail annules number 17 in Q. acutus but 38 in Q. solani n.sp.; also the phasmids in the former species are at mid-tail and in the latter are in anterior half of tail, at about 34%. Q. solani n.sp. is also closely related to Q. capitatus (Allen, 1955) Siddiqi, 1971 but differs in some characters. Head annules number eight and stylet length is 17 μm in Q. capitatus, but head annules are six and stylet length is 19 μm in Q. solani n.sp. In Q. capitatus T/ABW is 3 vs. 2.2 in Q. solani n.sp. Also, phasmids are located at mid-tail on Q. capitatus but at ahout one-third of the tail on Q. solani n.sp. A key to the 10 species of Quinisulcius is also presented. Scutylenchus koreanus (Choi &Geraert, 1971) Siddiqi, 1979 is recorded for the first time in Pakistan and morphometric data and illustrations given.  相似文献   

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Three new species of Endonura are described from Iran. Endonura dichaeta sp. n. can be recognized by an ogival labrum, head without chaetae O and E, chaeta D connected with tubercle Cl, tubercle Dl with five chaetae on head, absence of tubercles Di on thorax I and tubercle (Di+Di) of thorax V with 2+2 chaetae. Endonura ceratolabralis sp. n. is characterized by large body size, reduction of labral chaetotaxy, ogival labrum, head without chaeta O and fusion of tubercles Di and De on first thoracic segment. Endonura persica sp. n. is distinguished from its congeners by a nonogival labrum, absence of chaeta O, tubercles Dl and (L+So) with five and eight chaetae respectively and claw with inner tooth. The key to all species of the genus is given.  相似文献   

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Abstract We disagree with the assertion that recent human‐caused invasions differ substantially from historic natural invasions in their magnitudes and impacts on ecological processes. The position that exotic species are inherently ‘bad’ and should be eradicated is an ethical judgement, usually based on the naturalist fallacy or xenophobic prejudice; it is not a scientific judgement. The role of scientists in studying invasive species should be to gather, interpret and communicate information as accurately and objectively as possible.  相似文献   

19.
庄文颖 《菌物学报》2013,32(3):429-447
对我国盾盘菌属馆藏标本和近年来采集的材料进行分类学研究表明,中国已知该属31种。描述了3个新种,命名为柯氏盾盘菌、长孢盾盘菌和假小孢盾盘菌,对新种与其相近种的区别进行了讨论;根据前人的形态描述,对S. erinaceus,S.olivascens和S. lusatiae在中国的分布提出了质疑;根据对相关馆藏标本的观察,指出S. barlae、S. superba和S. vitreola在我国的报道系基于错误鉴定,它们应从中国物种名录中排除。文中提供了该属中国已知种的分种检索表。  相似文献   

20.
Trogoderma norfolkiana sp. nov. from Norfolk Island is described, illustrated and compared with related species; a differential diagnosis is also provided.

http://zoobank.org/urn:lsid:zoobank.org:pub:519C91E0-774C-4AA2-9870-2F6C24B32B7C  相似文献   

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