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1.
Chlamydomonas Ehrenb. is a unicellular volvocalean genus consisting of 400–600 species, most of which are known solely based on microscopy. In this study, a newly isolated strain of Chlamydomonas neoplanoconvexa (M. O. P. Iyengar) Nakada nom. nov. (≡Chlamydomonas planoconvexa M. O. P. Iyengar non J. W. G. Lund) was examined using light microscopy and combined 18S rRNA, rbcL and psaB gene phylogeny. The C. neoplanoconvexa strain was quite similar to Chlamydomonas perpusilla (Korshikov) Gerloff in terms of its small fusiform vegetative cells (~10 µm in length), parietal chloroplast containing a single pyrenoid, and nucleus posterior to the pyrenoid. However, C. neoplanoconvexa was distinguished from C. perpusilla based on the morphology of the papillae and pyrenoids. The two species belong to the clade Caudivolvoxa in the order Volvocales, but are distantly related to each other. Chlamydomonas perpusilla was shown to be sister to Chlorogonium Ehrenb. (clade Chlorogonia, within Caudivolvoxa), while C. neoplanoconvexa represented a second basal lineage within Caudivolvoxa, next to the clade Characiosiphonia. Although the morphology of C. neoplanoconvexa was not particularly outstanding, its unique phylogenetic position will encourage further investigation of this species and its uncultivated relatives.  相似文献   

2.
Eleotris species (Teleostei: Eleotridae) are one of the most common fish in Indo‐Pacific estuaries and insular freshwater streams. In these rivers, they are a sit‐and‐wait predator. They have an amphidromous life cycle, that is adults grow, feed and reproduce in rivers, while larvae have a marine dispersal phase. Larvae recruit back to rivers and settle in stream habitats. Primary characters used to determine Eleotris species are the presence and the disposition of cephalic sensory papillae rows on the operculum and under the eyes as well as scale row numbers. The morphology of these cephalic sensory papillae is of particular importance in this predatory genus as it is generally correlated in fish to predation and feeding. In this paper, we have established a molecular phylogeny of the genus based on the 12 mitochondrial protein‐coding genes to discuss the relationship between Indo‐Pacific Eleotris species. There is a well‐supported dichotomy in the molecular phylogeny, and this separation into two main clades is also morphologically visible, as it reveals a difference in the arrangement of cephalic sensory papillae. Indeed, the phylogeny distinguishes the species with the “open” pattern of the operculum sensory papillae and the species with the “closed” one. This phylogeny thus reflects the morphology of the opercular papillae. The evolution of this character is discussed in terms of the adaptation of the Eleotris genus to life in tropical insular river systems.  相似文献   

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The current sectional classification of the genus Aeschynanthus Jack, essentially based on seed morphology, presents some problems of species placement. A comparative SEM survey of seed and seed appendages was undertaken in order to assess the value of this classification. Seeds of 99 taxa (that is about two‐thirds of the estimated total) were examined and found to fall into two types, A and B. Type A has spiral testa cell orientation, papillae formed from a single cell and short smooth appendages. Type B is recognized by the straight orientation of the testa cells, combined with the presence of papillae formed from the raised ends of two adjacent cells on the long hair‐like appendages and usually on the testa. Only six of the investigated species did not fall into either category. Three have straight testa cell orientation combined with single‐cell papillae and short smooth appendages; the papillae and appendage characters place them in type A. Three have spiral testa cell orientation and short smooth appendages but the testa cells have slightly raised ends; these are also placed in Type A. The three subtypes in Type A are equivalent to the sections Haplotrichium s.s., Microtrichium and Aeschynanthus, but the divisions are less clear than those within Type B. However, other morphological characters support sectional separation. Type B subdivides into three: two subtypes equivalent to sections Polytrichium and Diplotrichium, and a third encompassing section Xanthanthos together with part of the current sect. Haplotrichium, and here referred to as sect. X. There is sufficient morphological correlation with seed type to make the sectional position of many species clear without recourse to seed, particularly in sects Polytrichium, Diplotrichium, Haplotrichium S.S. and Aeschynanthus. There is strong correlation between seed type and geographical distribution. Sects. Microtrichium and Aeschynanthus, with Type A seed, are essentially Malesian. Groups with Type B seed are largely confined to mainland south and south‐east Asia, except for sect. Polytrichium which is more widespread, possibly due to the greater effectiveness of a coma of hairs in wind dispersal. It is suggested that Type A seed, probably sect. Microtrichium, is the least determined and Type B sect. Polytrichium the most derived seed type. Based on these findings a revised key to the sections is provided.  相似文献   

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We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new sectional ranks; Synura, Peterseniae, Curtispinae (presence of body scales with slender spines, tubular scales and caudal scales). We further propose four new species based on phylogenetic analyses and unique scale characters: S. longitubularis sp. nov., S. sungminbooi sp. nov., S. soroconopea sp. nov. and S. lanceolata sp. nov. Lastly, we propose a new genus name, Neotessella, to replace the invalid use of the name Tessellaria.  相似文献   

8.
中国紫金牛属的分支分类学研究   总被引:2,自引:0,他引:2  
基于60个形态学性状,对中国广义报春花科(Primulaceae s.l.)紫金牛属(Ardisia)90个分类群的系统发育关系运用分支分析方法进行了分析。采用最简约性分析得到了100个同等简约树。50%多数规则一致树的分支结构与以前建立的紫金牛亚属划分系统基本一致。外类群酸藤子属、铁仔属、密花树属聚在分支树的最基部,紫金牛属为一单系类群。形态分支树的一致性指数和保持性指数和各分支内部支持率均较低,只在种与变种或亚种之间获得较高的支持率。高木亚属、腋序亚属、短序亚属、顶序亚属处于分支树较为基部的位置,推测这四个亚属的类群在紫金牛属中较为原始;圆齿亚属和锯齿亚属共同组成一大支,二者亲缘关系紧密,推测这两个亚属为该属中最为进化的类群。结合形态学对属内系统发育关系进行了讨论和推测了一些性状的演化趋势,以期为分类修订提供依据。  相似文献   

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Abstract Identification of aphid species is always difficult due to the shortage of easily distinguishable morphological characters. Aphid genus Toxoptera consists of species with similar morphology and similar to Aphis in most morphological characters except the stridulatory apparatus. DNA barcodes with 1 145 bp sequences of partial mitochondrial cytochrome‐coxidase I (COI) genes were used for accurate identification of Toxoptera. Results indicated mean intraspecific sequence divergences were 1.33%, whereas mean interspecific divergences were greater at 8.29% (0.13% and 7.79% if T. aurantii 3 and T. aurantii 4 are cryptic species). Sixteen samples were distinguished to four species correctly by COI barcodes, which implied that DNA barcoding was successful in discrimination of aphid species with similar morphology. Phylogenetic relationships among species of this genus were tested based on this portion of COI sequences. Four species of Toxoptera assembled a clade with low support in maximum‐parsimony (MP) analysis, maximum‐likelihood (ML) analysis and Bayesian phylogenetic trees, the genus Toxoptera was not monophyletic, and there were two sister groups, such as T. citricidus and T. victoriae, and two clades of T. aurantii which probably presented cryptic species in the genus.  相似文献   

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Holomastigotes is a protist genus (Parabasalia: Spirotrichonymphea) that resides in the hindguts of “lower” termites. It can be distinguished from other parabasalids by spiral flagellar bands that run along the entire length of the cell, an anterior nucleus, a reduced or absent axostyle, the presence of spherical vesicles inside the cells, and the absence of ingested wood particles. Eight species have been described based on their morphology so far, although no molecular data were available prior to this study. We determined the 18S rRNA gene sequences of Holomastigotes from the hindguts of Hodotermopsis sjostedti, Reticulitermes flavipes, Reticulitermes lucifugus, and Reticulitermes tibialis. Phylogenetic analyses placed all sequences in an exclusive and well‐supported clade with the type species, Holomastigotes elongatum from R. lucifugus. However, the phylogenetic position of Holomastigotes within the Spirotrichonymphea was not resolved. We describe two new species, Holomastigotes flavipes n. sp. and Holomastigotes tibialis n. sp., inhabiting the hindguts of R. flavipes and R. tibialis, respectively.  相似文献   

13.
Metapenaeopsis Bouvier, 1905 is the most diverse genus within Penaeidae. Metapenaeopsis shrimps exhibited subtle morphological differences, which make identification a difficult task based on taxonomic keys alone. In this study, we carried out DNA barcoding and phylogenetic analyses to examine taxonomy and phylogeny of genus Metapenaeopsis based on mitochondrial (COI) and nuclear (PEPCK and NaK) genes. Despite limited performance of DNA barcoding in delineating Metapenaeopsis shrimps, it questioned the taxonomic status of the two subspecies, Metapenaeopsis mogiensis intermedia and Metapenaeopsis mogiensis mogiensis, as well as three separate species: Metapenaeopsis provocatoria longirostris, Metapenaeopsis quinquedentata and Metapenaeopsis velutina. The major pattern of relationships between all studied taxa of Metapenaeopsis was similar across all analytical methods in which species with one-valved petasma were genetically distinct from those with two-valved petasma. As expected from morphology, the remaining species with stridulating organ constituted a strongly supported clade. In contrast, a paraphyletic clade was resolved for species without stridulating organ which contradicts Crosnier's morphological classification scheme for Metapenaeopsis. Overall, the present molecular data indicated that the shape of petasma and stridulating organ were both phylogenetically significant morphological characters for this genus, adding further evidence for the Crosnier's proposal.  相似文献   

14.
Analysis of a morphological dataset containing 152 parsimony‐informative characters yielded the first phylogenetic reconstruction spanning the South American characiform family Anostomidae. The reconstruction included 46 ingroup species representing all anostomid genera and subgenera. Outgroup comparisons included members of the sister group to the Anostomidae (the Chilodontidae) as well as members of the families Curimatidae, Characidae, Citharinidae, Distichodontidae, Hemiodontidae, Parodontidae and Prochilodontidae. The results supported a clade containing Anostomus, Gnathodolus, Pseudanos, Sartor and Synaptolaemus (the subfamily Anostominae sensu Winterbottom) albeit with a somewhat different set of relationships among the species within these genera. Anostomus as previously recognized was found to be paraphyletic and is split herein into two monophyletic components, a restricted Anostomus and the new genus Petulanos gen. nov. , described herein. Laemolyta appeared as sister to the clade containing Anostomus, Gnathodolus, Petulanos, Pseudanos, Sartor and Synaptolaemus. Rhytiodus and Schizodon together formed a well‐supported clade that was, in turn, sister to the clade containing Anostomus, Gnathodolus, Laemolyta, Petulanos, Pseudanos, Sartor and Synaptolaemus. Anostomoides was sister to the clade formed by these nine genera. Leporinus as currently defined was not found to be monophyletic, although certain clades within that genus were supported, including the species with subterminal mouths in the former subgenus Hypomasticus which we recognize herein as a genus. Abramites nested in Leporinus, and Leporellus was found to be the most basal anostomid genus. The presence of cis‐ and trans‐Andean species in Abramites, Leporellus, Leporinus and Schizodon, all relatively basal genera, suggests that much of the diversification of anostomid species pre‐dates the uplift of the Andean Cordilleras circa 11.8 million years ago. Several important morphological shifts in anostomid evolution are illustrated and discussed, including instances of convergence and reversal. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 70–210.  相似文献   

15.
Cariniana as previously circumscribed is a genus of 16 species restricted to neotropical forest habitats on well-drained sites. A phylogenetic analysis of the genus based on 33 morphological and anatomical characters was undertaken. The results show that Cariniana consists of two clades: the Allantoma/Cariniana decandra clade includes Allantoma lineata and seven species of actinomorphic-flowered Cariniana and is characterized by 5-merous flowers, carnose petals, incurved petal apex, scarcely lobed calyces, eucamptodromous secondary veins, dichotomizing venation, and poorly developed areolation; the C. legalis clade is made up of nine species and is characterized by an obliquely zygomorphic androecium, reticulate tertiary venation, and anomocytic stomata. The actinomorphic-flowered Cariniana are more closely related to the monotypic Allantoma lineata than they are to the species of the C. legalis clade. In order to reflect these relationships, Cariniana is divided into two genera: species in the C. legalis clade, which includes the generic type C. legalis, remain as Cariniana while species of Cariniana in the Allantoma/Cariniana decandra clade are transferred to Allantoma. The following new combinations are proposed: Allantoma decandra, A. integrifolia, A. kuhlmannii, A. pluriflora (a nomen novum for Cariniana multiflora because Allantoma multiflora is a synonym of Couratari multiflora), A. pachyantha, A. pauciramosa, and A. uaupensis.  相似文献   

16.
Ogrinc  N.  Hintelmann  H.  Eckley  C.  Lojen  S. 《Hydrobiologia》2003,496(1-3):207-213
The functional morphology of the feeding palps and prostomium of the spionid polychaetes Streblospio benedicti and S. shrubsolii was studied. Three functional groups of cilia of the feeding palps were found on both species – frontal cilia, latero-frontal cirri and lateral cilia. Frontal cilia line the food groove and transport food particles to the pharynx, and have been reported for all spionid polychaetes except species of the genus Scolelepis. Latero-frontal cirri deflect particles onto the frontal surface and have been observed in several spionid genera including Paraprionospio, Streblospio, Polydora and Dipolydora. Lateral cilia beat in continuous metachronal waves creating lateral vortices that potentially entrain suspended particles, and are known in Paraprionospio and Streblospio. The two species of Streblospio did differ in the distribution of prostomial papillae. These papillae are eversible and thought to function in particle selection as particles on the pharynx come in contact with the papillae. Prostomial papillae were restricted to the peripheral surface of S. benedicti and were widely scattered on all surfaces of the prostomium of S. shrubsolii. A conical tentaculate structure occurs between the branchiae of the first setiger of S. benedicti, but only a low raised elevation is present on S. shrubsolii.  相似文献   

17.
Selenidium is a genus of gregarine parasites that infect the intestines of marine invertebrates and have morphological, ecological, and motility traits inferred to reflect the early evolutionary history of apicomplexans. Because the overall diversity and phylogenetic position(s) of these species remain poorly understood, we performed a species discovery survey of Selenidium from tube‐forming polychaetes. This survey uncovered five different morphotypes of trophozoites (feeding stages) living within the intestines of three different polychaete hosts. We acquired small subunit (SSU) rDNA sequences from single‐cell (trophozoite) isolates, representing all five morphotypes that were also imaged with light and scanning electron microscopy. The combination of molecular, ecological, and morphological data provided evidence for four novel species of Selenidium, two of which were established in this study: Selenidium neosabellariae n. sp. and Selenidium sensimae n. sp. The trophozoites of these species differed from one another in the overall shape of the cell, the specific shape of the posterior end, the number and form of longitudinal striations, the presence/absence of transverse striations, and the position and shape of the nucleus. A fifth morphotype of Selenidium, isolated from the tube worm Dodecaceria concharum, was inferred to have been previously described as Selenidium cf. echinatum, based on general trophozoite morphology and host association. Phylogenetic analyses of the SSU rDNA sequences resulted in a robust clade of Selenidium species collected from tube‐forming polychaetes, consisting of the two new species, the two additional morphotypes, S. cf. echinatum, and four previously described species (Selenidium serpulae, Selenidium boccardiellae, Selenidium idanthyrsae, and Selenidium cf. mesnili). Genetic distances between the SSU rDNA sequences in this clade distinguished closely related and potential cryptic species of Selenidium that were otherwise very similar in trophozoite morphology.  相似文献   

18.
The marmosets, tribe Callitrichini, are the most speciose clade in the subfamily Callitrichinae, containing 21 species. However, there is no consensus among molecular and morphological systematists as to how many genera should be recognized for the group. To test the morphological support for the alternative generic classifications, this study presents a comprehensive phylogenetic analysis. It is the first such analysis to include all 21 species and employ continuous and discrete osteological, pelage and tegument, karyological and vocal characters. This dataset was combined with nucleotide sequences from two mitochondrial and four nuclear regions. Separate analyses showed that, among morphological datasets, osteological characters were best at solving relationships at more inclusive levels, whilst pelage characters were most informative at the interspecific level. This suggests the presence of different transformation rates for the two character sets. When a single most parsimonious tree was obtained using the 83‐character matrix, three main clades were identified, supporting the division of the marmosets into three genera: Callithrix, Cebuella and Mico. The total evidence analysis that included an additional 3481 molecular characters corroborated most of the morphology‐based clades and also supported a three‐genus classification of the marmosets. This is the first morphological study to support an Amazonian marmoset clade (Cebuella Mico), which is also strongly supported in exclusively molecular phylogenies, and to synonimize Callibella under Mico.  相似文献   

19.
A cladistic analysis was conducted to test the monophyly of Eschweilera and Lecythis as well as to examine the relationships of these two genera and their close relatives Bertholletia and Corythophora. The study included 86 species, representing all four genera and covering the range of taxonomic and morphological variation in the genera. The data matrix included 49 parsimony-informative characters derived from vegetative, floral, fruit, and seed morphology and anatomy. The results based on the consensus of all most parsimonious trees indicate that Bertholletia, Corythophora, Eschweilera, and Lecythis form a clade supported by brachyparacytic stomata, the absence of pedicels (with subsequent reversals in several clades), a two or four-locular ovary, the presence of an aril, and the absence of cotyledons. Within the clade, the monophyly of Corythophora is supported by the presence of inflorescence scales and the absence of nectar. Eschweilera is monophyletic only if E. congestiflora and E. simiorum are excluded. The monophyly of Eschweilera is supported by the presence of a two-locular ovary. Lecythis is not monophyletic, but sections Corrugata, Pisonis, and Poiteaui are monophyletic. Three species of section Lecythis are more closely related to Eschweilera, and other species of section Lecythis along with Bertholletia excelsa remain as unresolved.  相似文献   

20.
Hartmannellid amoebae are an unnatural assemblage of amoeboid organisms that are morphologically difficult to discern from one another. In molecular phylogenetic trees of the nuclear‐encoded small subunit rDNA, they occupy at least five lineages within Tubulinea, a well‐supported clade in Amoebozoa. The polyphyletic nature of the hartmannellids has led to many taxonomic problems, in particular paraphyletic genera. Recent taxonomic revisions have alleviated some of the problems. However, the genus Saccamoeba is paraphyletic and is still in need of revision as it currently occupies two distinct lineages. Here, we report a new clade on the tree of Tubulinea, which we infer represents a novel genus that we name Ptolemeba n. gen. This genus subsumes a clade of hartmannellid amoebae that were previously considered in the genus Saccamoeba, but whose mitochondrial morphology is distinct from Saccamoeba. In accordance with previous research, we formalize the clade as distinct from Saccamoeba. Transmission electron microscopy of our isolates illustrate that both molecularly discrete species can be further differentiated by their unique mitochondrial cristal morphology.  相似文献   

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