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1.
Mating behaviour and spermatophore morphology of the south-east Asian whip spider Phrynichus orientalis is described. During courtship there is less bodily contact between mates than in other studied species of the same genus. However, a peculiarity for the species is that the pair often pauses for minutes, sitting front to front without any movement. For spermatophore formation, the male shifts his body under that of the female like in many other species. However, after spermatophore formation, the male lures the female to the spermatophore instead of pulling her as in most other species studied. The spermatophore differs from those of most other species of the genus by the fact that the cushions in front of the sperm masses are replaced by a hard, transparent mass which has the same function as the cushions. Mating behaviour and spermatophore morphology of P. orientalis thus show peculiarities that so far have not been described for other species of the genus. It is not clear whether these characters should be considered plesiomorphic or apomorphic. But it does clearly show that there is more diversity within this genus than expected.  相似文献   

2.
The Miocene gecko in amber, Sphaerodactylus dommeli, is one of the best‐preserved fossil gekkotan species; nonetheless, its identity has been questioned and it has been insinuated to be an iguanian referable to the mega‐diverse genus Anolis. In this paper, we provide digital X‐rays and new osteological evidence that include 11 characters that reaffirms its placement within the infraorder Gekkota and eight characters that specifically place this fossil within the species‐rich genus Sphaerodactylus, in which it was originally described. This contribution seeks to eliminate remaining scepticism about the generic allocation of this species, and to provide a reliable calibration point for ongoing research in squamate phylogenetics, especially for biogeographical studies and molecular dating inference. This contribution also reviews many diagnostic characters for the two genera in question, which is critical for the correct identification of amber‐embedded specimens representing the rich Hispaniolan lizard paleocommunity.  相似文献   

3.
Ferrer A  Raja HA  Shearer CA 《Mycologia》2008,100(4):642-646
A new fungus collected from submerged wood in Costa Rica and Ecuador has ascostromatic ascomata with fissitunicate asci and lacks pseudoparaphyses, characters that place it in the Dothideaceae (Dothideales). It is unusual in the order because it has white ascomata. Based on other morphological characters however this fungus could not be accommodated in any existing genus in the Dothideaceae and it is described herein as a new genus and species, Lucidascocarpa pulchella. These morphological features are characteristic of L. pulchella: ascomata glistening, white, each with a long, periphysate neck; a membranous peridium composed of 5-7 thin-walled, hyaline cells; pseudoparaphyses absent; asci fissitunicate, clavate, eight-spored; ascospores seven-septate, hyaline, multiguttulate, verruculose, surrounded by a large, regular, gelatinous sheath.  相似文献   

4.
5.
Abstract. Svenzea zeai , abundant on many deep Caribbean fore-reef habitats but of uncertain systematic position within the Demospongiae, is closely examined histologically and cytologically for evidence of its phylogenetic relationship beyond the traditional analysis of gross morphology and skeletal structure. We document that S. zeai is a bacteriosponge containing substantial quantities of unicellular photosynthetic and autotrophic microbes; that the most abundant cell type is an unusual cell with refractile granules that only few species share and whose composition and function are still enigmatic; and that it produces the largest—by a factor of 3—embryos and larvae recorded in the phylum Porifera. A combination of characters such as the granular cells, ciliary pattern, and aspects of larval shape and behavior are comparable with those of Scopalina ruetzleri , family Dictyonellidae, a prominent member of the Caribbean mangrove community. These results support our earlier decision to establish Svenzea as a new genus in Dictyonellidae to accommodate its unprecedented skeletal structure, styles in isodictyal reticulation.  相似文献   

6.
A new species of Moldenhawera is described from the state of Bahia in Brazil. Moldenhawera intermedia differs from all other species in the genus by its combination of pinnate leaves with acute to caudate apices, its pink petals, pentamerous flowers, and the staminode filaments 1.5 to 2.5 × longer than the anthers which dehisce by slits not pores. The species has a suite of morphological characters that place it intermediate between all three described sections of the genus, suggesting that the supra-specific taxonomy of Moldenhawera will benefit from a future reappraisal.  相似文献   

7.
Abstract.— Phylogenetic inertia is a difficult issue in evolutionary biology because we have yet to reach a consensus about how to measure it. In this study a comparative approach is used to evaluate phylogenetic inertia in 14 demographic and morphological characters in 10 species and one subspecies of the genus Tithonia (Asteraceae). Three different methods, autocorrelational analysis, phylogenetic correlograms, and ancestor-state reconstruction, were used to evaluate phylogenetic inertia in these traits. Results were highly dependent on the method applied. Autoregression and phylogenetic eigenvector regression (PVR) methods found more inertia in morphological traits. In contrast, phylogenetic correlograms and ancestor-state reconstruction suggest that morphological characters exhibit less phylogenetic inertia than demographic ones. The differences between results are discussed and methods are compared in an effort to understand phylogenetic inertia more thoroughly.  相似文献   

8.
杜鹃属植物的分类历来都十分重视叶片表皮特征的分类学价值,无论是在各亚属之间还是在种及种下等级的划分中都很强调此类特征的作用。贵州省位于世界现代杜鹃分布中心边缘及向东部散布的过渡地带,省内自然分布的杜鹃种类资源丰富而又独具特色,包括很多尚未深入研究的特有类群。为进一步研究贵州杜鹃属植物的属下系统分类关系,该文对自然分布于贵州的30种杜鹃进行了叶背显微形态特征研究,其中有28种的叶背表皮特征为首次报道。研究材料全部来自采于贵州西北部百里杜鹃自然保护区内的杜鹃属植物,包括杜鹃亚属4种、糙叶杜鹃亚属1种、常绿杜鹃亚属22种、马银花亚属1种及映山红亚属2种,共计30种。研究方法为取成熟叶片处理后在JSM-6490型扫描电镜下对叶背表皮进行观测。叶背鳞片类型的划分方法参照前人工作。结果表明:这30种杜鹃叶片叶背表皮形态特征在电子显微镜下表现出明显的多样性,如有鳞类杜鹃具有鳞片而其他类群则无,叶表面有或无表皮毛,表皮毛排列稀疏或密生,气孔器未见或偶见,散生于乳突状或非乳突状突起之间,或角质层增厚气孔器下陷,内、外拱盖表面粗糙或光滑,气孔器周围有或无间断的条形突起,突起呈环状或羽状等,但在同一亚属或亚组中又呈现出或多或少的一致性。研究讨论表明,叶背表皮显微形态特征在杜鹃属植物的属下系统分类中具有重要的研究价值。  相似文献   

9.
Exorhopala ruficeps is a rare parasitic plant of the family Balanophoraceae, endemic to the north-western part of Peninsular Malaysia. It was originally described in Rhopalocnemis and later placed in a new monotypic genus on the basis of the exogenous origin of its inflorescences. A new collection of material enabled a detailed morphological study, the results of which are presented here. Inter alia, it is documented that the inflorescences originate endogenously as in all other Balanophoraceae. However, no volva is formed and the tuber-tissue covering the emerging inflorescence crumbles into pieces. The inflorescence and flower characters established here are neither in full accordance with Rhopalocnemis nor do they justify a genus of its own, but instead place the species in Helosis , which thus becomes a genus of transpacific distribution. The new combination is Helosis ruficeps (Ridl.) R. K. Eberwein.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 513–517.  相似文献   

10.
Sun P  Clamp J  Xu D  Kusuoka Y  Miao W 《Protist》2012,163(1):129-142
Recent phylogenetic analyses of the peritrich genus Vorticella have suggested that it might be paraphyletic, with one Vorticella species - Vorticella microstoma grouping with the swimming peritrichs Astylozoon and Opisthonecta in a distant clade. These results were based on very limited taxon sampling and thus could not be accepted as conclusive evidence for revising the generic classification. We tested paraphyly of the genus Vorticella by making a new analysis with a broad range of samples from three continents that yielded 52 new sequences of the gene coding for small subunit rRNA. Our results, together with the available sequences in Genbank, form a comprehensive set of data for the genus Vorticella. Analyses of these data showed that Vorticella microstoma morphotypes, Astylozoon, and Opisthonecta form a well-supported, monophyletic clade, that is distinct from and basal to the family Vorticellidae containing other species of Vorticella. Paraphyly of the genus Vorticella and family Vorticellidae was strongly confirmed by these results. Furthermore, the two clades of Vorticella identified by the SSU rRNA gene are so genetically diverse whereas the genetic distances within the one containing Vorticella microstoma morphotypes, Astylozoon, and Opisthonecta were so slight, which marked it as a separate family that must be defined by molecular characters in the absence of unifying morphological and morphogenetic characters. An emended characterization and status of the genus Vorticella, the families Vorticellidae and Astylozoidae are presented and discussed.  相似文献   

11.
The phylogenetic relationships of the family Congiopodidae are inferred based on morphological characters. The monophyly of this family is supported by 13 unambiguous apomorphic characters, including four autapomorphies among the superfamily Scorpaenoidea. The Congiopodidae shares 26 apomorphic characters with other scorpaenoid taxa, and these characters are considered to also support the monophyly of the family. Upon completion of the phylogenetic analysis using the characters in 39 transformation series, it was assumed that the family is unambiguously supported by five characters (and also by three and one characters when ACCTRAN and DELTRAN are used, respectively) and is branched into two major clades, including Congiopodus and Alertichthys plus Zanclorhynchus, respectively. Based on the phylogenetic relationships, a new classification, recognizing two subfamilies (Congiopodinae and Zanclorhynchinae) in the family Congiopodidae, is proposed. The genus Perryena, that was recently inferred being closely related to the Tetrarogidae (although many authors included it in the Congiopodidae), is provisionally placed into the Congiopodidae as incertae sedis.  相似文献   

12.
A phylogenetic analysis of the Old World genus Doronicum (26 species, 4 subspecies) based on sequence data of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA, the chloroplast spacer trnL-F, and morphology is presented. Congruence among the three data sets was explored by the computing of several indices, all of which suggest homogeneity between only the two molecular matrices. We argue that the morphological data set contains poor phylogenetic signal and advocate simultaneous analysis of the three data sets (total evidence approach) so that morphological characters are tested for homology by congruence with molecular data. The resulting phylogenetic hypothesis allows several well-supported conclusions including the placement of a Corsican endemic (D. corsicum), sister to the remainder of the genus, and the inference that an early southern European or Mediterranean diversification took place in the genus. Shifts in morphological characters (e.g., homocarpy to heterocarpy) are confirmed to have evolved several times. Results from comparative studies of sequence data of the chloroplast gene ndhF support inclusion of Doronicum in tribe Senecioneae.  相似文献   

13.
14.
Sundberg, P., Gibson, R. & Olsson, U. (2003). Phylogenetic analysis of a group of palaeonemerteans (Nemertea) including two new species from Queensland and the Great Barrier Reef, Australia. — Zoologica Scripta, 32, 279–296.
Based on 18S rDNA nucleotide sequences and morphological characters, we reconstruct the phylogeny for a group of palaeonemerteans estimated to be monophyletic. Two new palaeonemertean species from Queensland and the Great Barrier Reef, Australia are included in the phylogenetic analysis. The results confirm that one of the species, Cephalothrix queenslandica sp. n., is part of the Cephalothrix–Cephalotrichella–Procephalothrix group. These genera are redefined phylogenetically under the name Cephalothrix based on the cladistic analysis. The other species, Balionemertes australiensis gen. et sp. n., is placed in a new genus which forms a sister taxon to Cephalothrix . The morphology of both new species is described in detail.  相似文献   

15.
Abeliophyllum, a monotypic endemic genus of Oleaceae, resembles Forsythia in various morphological characters, but its phylogenetic position is disputed and no embryological study of the genus has been carried out. We investigated more than 40 embryological characters of Abeliophyllum, compared them with previous information on Oleaceae, and discusses its phylogenetic relationships. Abeliophyllum is similar to other genera of Oleaceae in many embryological features, having some distinct features such as the mode of anther wall formation, formation of a nucellar cap, and formation of obturator and hypostase. The basic type of anther wall development and formation of a nucellar cap have not previously been reported in Oleaceae. In addition, differentiation of the obturator and formation of hypostase are not reported in the previously investigated genera of the family. Compared with close relatives, the seed coat structure of Abeliophyllum resembles Forsythia more than Fontanesia and supports existing molecular data which place Abeliophyllum as the sister group of Forsythia.  相似文献   

16.
The new recent genus and species of three‐toed jerboas (Rodentia: Dipodinae), from southern Ningxia, China, is described. This form demonstrated a unique mixture of external, cranial, and dental characters that individually are typical for one or another of all known genera of Dipodinae. Based on morphological characters, it is recovered as the part of Dipodinae tree, distinct from all other members due to its unique combination of morphological characters, and appears to be a nearly ideal living ancestor of all other dipodines. In contrast to morphology, the molecular data indicate a relatively young age for this lineage and consistently place it as the sister group to Stylodipus. The results of the molecular clock analysis suggest that the separation of the two lineages dates back to the Early Pliocene or the Pliocene/Miocene boundary. The estimated geographic range of the new form seems extremely small. The conservational status of the new species remains to be determined; however, the available information suggests that it requires protection.  相似文献   

17.
A further paper dealing with West Atlantic Gnathostomulida presents the new monotypic genus Tenuignathia. The presence of a full sensorium and a cuticular bursa place the new genus within the order Bursovaginoidea, sub-order Scleroperalia; the simple jaws and pharynx, the bipartite ciliary pits as well as epithelial characters clearly suggest inclusion in the family Mesognathariidae. Found in Florida, North Carolina and Bermuda so far, Tenuignathia displays an unusually wide range of jaw length even within a narrow geographic range, which will be the subject of a separate study.  相似文献   

18.
Small R 《Bioethics》2002,16(4):307-334
Some ethical dilemmas in health care, such as over the use of age as a criterion of patient selection, appeal to the notion of life expectancy. However, some features of this concept have not been discussed. Here I look in turn at two aspects: one positive — our expectation of further life — and the other negative — the loss of potential life brought about by death. The most common method of determining this loss, by counting only the period of time between death and some particular age, implies that those who die at ages not far from that one are regarded as losing very little potential life, while those who die at greater ages are regarded as losing none at all. This approach has methodological advantages but ethical disadvantages, in that it fails to correspond to our strong belief that anyone who dies is losing some period of life that he or she would otherwise have had. The normative role of life expectancy expressed in the 'fair innings' attitude arises from a particular historical situation: not the increase of life expectancy in modern societies, but a related narrowing in the distribution of projected life spans. Since life expectancy is really a representation of existing patterns of mortality, which in turn are determined by many influences, including the present allocation of health resources, it should not be taken as a prediction, and still less as a statement of entitlement.  相似文献   

19.
Acanthochlamydoideae, a new subfamily of Amaryllidaceae, is proposed in the present paper, based upon the monotypic genus Acanthochlamys which was detected by the writer in 1979 and named Didymocolpus as a new genus but was preceded by P. C. Kao in 1980 under the former name. The genus is indeed of great morphological interest. It has semicylindric leaves with a deep furrow on the ventral and dorsal sides respectively. The lower part of the leaf is connate with, or adnate to, the lower midrib of a rather large and membranous vagina . Such a feature, as far as we know, is very rare in the monocotyledons. The flower resembles that of Amaryllidaceae in having inferior ovary, six stamens and corolla-like perianth with a rather long tube. But it is quite different in other characters, such as head-like cyme, leaf-like bracts and bisulcate leaves, which all are foreign to any taxon known in the Amaryllidaceae. On the other hand, it bears some resemblance particularly in habit and inflorescence to Campynemanthe of the Hypoxidaceae, and also to Borya and Bartlingia of the Liliaceae (in the tribe Johnsonieae), but differs in its long perianth-tube and curious leaf structure. It is highly probable that the resemblance between them is only superficial and not indicative of direct or close relationship. This is no doubt a very curious plant of which we still know incompletely, and for which an appropriate place in the monocotyledons has not yet been found. Considering its floral characters, however, it seems safe for the present to place it as a separate subfamily in the Amaryllidaceae and is juxtaposed with the Ixiolirioideae and Amaryllidoideae, the only two subfamilies of Amaryllidaceae according to H. Melchior (1964), and, of course, to either of them it is not directly related. Its true affinity remains problematic. The only species, Acanthochlamys bracteata, is found in Mar-er-kan (102°12'N, 31°47'E), Qian-ning (101°30'N, 30°33'E), Xiang-cheng (99°39'N, 28°54'E) and Dau cheng (100°10'N, 29°03'E) in western Sichuan of southwest China, in open bushland or grassland at an altitude between 2700—3500 meters. Its geographical distribution is mapped and its morphological details are illustrated to facilitate its identification.  相似文献   

20.
The genus Cicer has traditionally been placed in the Vicieae, although it has a number of morphological characters which suggest that it is out of place in that tribe and that its affinities lie elsewhere. A survey of pollen morphology in Cicer , the other genera of the Vicieae, the Trifolieae and the Ononideae has been carried out to help determine the relationships of Cicer. The tribe Vicieae (without Cicer) is very homogeneous and is characterized by its long, rectangular pollen grains with small, heavily thickened endoapertures. The Trifolieae is more variable in its pollen morphology but, in general, has rather similar grains to the Vicieae although the structure of the endoaperture is different. The Ononideae and Cicer have nearly spheroidal pollen with very large, unthickened endoapertures. It therefore appears that as far as pollen characters are concerned, Cicer does not belong in the Vicieae but has much more in common with the Ononideae.  相似文献   

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