A Phylogenetic Analysis of Families in the Hamamelidae

A cladistic analysis of the families in the Hamamelidae is made in the present paper. As a monophyletic group, the subclass Hamamelidae includes 19 families, namely, the Trochodendraceae, Tetracentraceae, Cercidiphyllaceae, Eupteleaceae, Eucommiaceae, Hamamelidaceae (incl. Rhodoleiaceae and Altingiaceae), Platanaceae, Daphniphyllaceae, Balanopaceae, Didymelaceae, Myrothamnaceae, Buxaceae, Simmondsiaceae, Casuarinaceae, Fagaceae (incl. Nothofagaceae), Betulaceae, Myricaceae, Rhoipteleaceae and Juglandaceae. The Magnoliaceae was selected for outgroup comparison after careful consideration. Thirty-two informative character states were used in this study. Three principles, namely, outgroup comparison, fossil evidence and generally accepted viewpoints of morphological evolution, were used for polarization of the characters. An incompatible number concept was first introduced to evaluate the reliable degree of polarization of the characters and, by this method, the polarization of the three character states was corrected. A data matrix was constructed by the 19 ingroup families and 32 character states. The data matrix was analysed with the Minimal Parallel Evolutionary Method, Maximal Same Step Method (Xu 1989), and Synthetic Method. Three cladograms were constructed and a parsimonious cladogram (Length= 131)was used as the base for discussing the systematic relationships of families in the Hamamelidae. According to the cladogram, the earlist group differented in the subclass Hamamelidae consists of two vesselless wood families, the Trochodendraceae and Tetracentraceae. This result supports the concept proposed by Takhtajan (1987)and Cronquist (1981, 1988)that the Trochodendrales is probably a primitive taxon in the Hamamelidae. As in a clade group, the Cercidiphyllaceae, Eucommiaceae, Balanopaceae and Didymelaceae originated apparently later than the Trochodendrales. The Cercidiphyllaceae diverged earlier in this group, which implies that this family and the Trochodendrales form a primitive group in the subclass. The Cercidiphyllaceae is either placed in Hamamelidales (Cronquist 1981, Thorne 1983), or treated as an independent order (Takhtajan 1987).This analysis suggests that the Cercidiphyllaceae is a relatively isolated taxon, far from the Hamamelidaceae but close to the Trochodendrales in relation. The Eucommiaceae and Didymelaceae are both isolated families and considered as two distinct orders (Takhtajan 1987, Cronquist 1981, 1988).The Balanopaceae is included in the Fagales (Cronquist 1981, 1988) or Pittosporales (Thorne 1983), or treated as a distinct order Balanopales (Takhtajan 1987 ).Obviously the Balanopaceae and Eucommiaceae are not closely related because of the sole synapomorphy (placentation).In fact these four families are more or less isolated taxa and it is probably more reasonable to treat them as independent orders. Cronquist ( 1981, 1988) places the Eupteleaceae, Platanaceae and Myrothamnaceae in the Hamamelidales, while Takhtajan (1987)puts Hamamelidaceae and Platanaceae into the Hamamelidales and treats the Eupteleaceae and Myrothamnaceae as two independent monofamilial orders. These three families are grouped by more synapomorphies (palmateveined, serrate or lobate leaves, deciduous and anemophilous plants)which may indicate their close phylogenetical affinity. A core group of the Hamamelidae includes ten families, among which the Hamamelidaceae originated earlier than the others, so that it is a relatively primitive family. The Betulaceae, Fagaceae and Myricaceae differentiated later than the Hamamelidaceae. The former two are very closely related, and thus thought to be two neighbouring orders by Takhtajan (1987)or included in the Fagales by Cronquist (1981, 1988)and Thorne (1983). The Myricaceae and Fagaceae are connected in the cladogram by only a single synapomorphy (endosperm absent), and therefore the close relationship does not exist between them. The Buxaceae, Simmondsiaceae and Daphniphyllaceae form an advanced group, in which they are weakly linked with each other by only one synapomorphy (pollen grains＜25μm). The Daphniphyllaceae is closely related to the Simmondsiaceae, but the Buxaceae is rather isolated. The Rhoipteleaceae and Juglandaceae share a number of synapomorphies (axile placentation, endosperm absent, embryo larger, fruit indehiscent) , forming a highly specialized group. The opinion that the Juglandales is composed of the Juglandaceae and Rhoipteleaceae(Cronquist 1981; 1988, Lu et Zhang 1990)is confirmed by this analysis. A contrary point of view, which treated them as two distinct orders by Takhtajan (1987), apparently could not be accepted. The Casuarinaceae was regarded as the primitive angiosperm (Engler 1893), but in fact it is a highly reduced and specialized group. It is united with Rhoipteleaceae and Juglandaceae by four synapomorphies, i. e. placentation type, endosperm absent, embryo large and fruit indehiscent. However, the family presents six autapomorphies, and thus the position of the Casuarinaceae as an advanced family is confirmed by this analysis. Finally a strict consensus tree, which represents the phylogenetic relationships of thefamilies in the Hamamelidae, was given as a result of the analysis.     

Chloroplast DNA diversity in wild and cultivated species of rice (Genus Oryza,section Oryza). Cladistic-mutation and genetic-distance analysis

Summary Using a novel nonaqueous procedure, chloroplast DNA was isolated from 318 individual adult rice plants, representing 247 accessions and the breadth of the diversity in section Oryza of genus Oryza. Among them, 32 different cpDNA restriction patterns were distinguished using the restriction endonucleases EcoRI and AvaI, and they were further characterized by restriction with BamHI, HindIII, SmaI, PstI, and BstEII enzymes. The differences in the electrophoretic band patterns were parsimoniously interpreted as being the result of 110 mutations, including 47 restriction site mutations. The relationships between band patterns were studied by a cladistic analysis based on shared mutations and by the computation of genetic distances based on shared bands. The deduced relationships were compared with earlier taxonomical studies. The maternal parents for BC genome allotetraploids were deduced. Within species, cpDNA diversity was found larger in those species with an evolutionary history of recent introgression and/or allotetraploidization. Occasional paternal inheritance and recombination of cpDNA in rice was suggested.     

Phylogenetic relationships of the stromateoid fishes (Perciformes)

The phylogenetic relationships of all 16 genera (plus Psenes pellucidus) of the suborder Stromateoidei were estimated cladistically based on 43 osteological, myological, and external characters. Thirty equally parsimonious trees were obtained. Based on the strict consensus tree, Centrolophidae was nonmonophyletic, Psenopsis being placed as a sister group of a clade comprising Amarsipus, Ariomma, nomeids, Tetragonurus, and stromateids. Schedophilus formed a sister group relationship with Seriolella. The relationships among the Centrolophus, Hyperoglyphe, Icichthys, Tubbia, Schedophilus+Seriolella clade, and Psenopsis+Amarsipus+Ariomma+nomeids+Tetragonurus+stromateids clade were unresolved. Amarsipus, which is unique within the suborder in lacking a pharyngeal sac, was nested within the stromateoid clade, being a sister group of the clade including Ariomma, nomeids, Tetragonurus, and stromateids. The absence of a pharyngeal sac in Amarsipus was interpreted as a reversal, its presence in the Stromateoidei therefore being considered as a synapomorphy. Ariomma was placed as the sister group of a clade comprising nomeids, Tetragonurus, and stromateids. Monophyly of the Nomeidae and Stromateidae were supported by 2 and 11 synapomorphies, respectively.     

中国菊属一些种的分支分类学研究

运用分支分析方法研究了12种原产中国的野生菊属植物的系统发育关系,并引入了若干栽培品种及部分杂种一代植株作为分析材料。研究结果表明：分支分析方法有效而准确地将分类群分类,并揭示出毛华菊（Dendranthemarestitum）与菊花（Dendranthema×gran-diflorum）同为菊属植物中进化程度较高的种,部分种间杂种也已进入栽培类群。同时还发现不同性状在各品种间平行进化的现象。根据上述结果,作者讨论了中国菊属植物的系统进化及菊花起源问题。     

A palaeontological and phylogenetical analysis of squaliform sharks (Chondrichthyes: Squaliformes) based on dental characters

Squaliformes comprise the major proportion of modern deep-water sharks, yet their fossil history and phylogenetic relationships are still poorly understood. New analyses have been undertaken, however, and new living and fossil species have been discovered during the past 10 years. A cladistic analysis involving 29 dental characters has been made and most living and fossil genera are included. On the basis of their dental morphology, the monophyly of the Squaliformes can be supported if the fossil genus Protospinax is excluded. The traditional phylogenetic positions of most living genera, Protosqualus, Cretascymnus and Eoetmopterus, are confirmed despite the fact that the Oxynotidae, Etmopterinae, Palaeomicroides, Proetmopterus and Microetmopterus have some atypical phylogenetic relationships within the Squaliformes. The addition of the palaeontological data in a phylogenetic tree including fossil and living Squaliformes demonstrates some gaps in the fossil record. Nevertheless, and as a consequence of that stratigraphy-phylogeny inference, two particular events can be pinpointed in the history of the Squaliformes: the first one occurs after the major Cenomanian-Turonian anoxic event and the second one after the Cretaceous/Tertiary crisis. The first radiation involves the majority of the living Squaliformes (Somniosinae, Centrophorinae, most of the Etmopterinae, Oxynotinae) in deep-sea waters, the second, the more epipelagic sharks (most of the Dalatiidae), suggesting a secondary adaptation to more shallow environments.     

Molecular systematics of Solanum section Lycopersicum (Lycopersicon) using the nuclear ITS rDNA region

The phylogenetic relationships of all nine known tomato species of Solanum section Lycopersicum, together with other Solanum sections and species from several related genera, were investigated using parsimony analysis of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (rDNA). Most parsimonious reconstructions divided the section Lycopersicum into three clades, reflecting their mating behaviour and fruit colour. Data from sequencing studies were congruent with those from morphological and other molecular investigations, and provided detailed information concerning species relationships. Received: 11 July 2000 / Accepted: 17 April 2001     

An Algorithm for Cladistic Taxonomy—Method of Maximal Same Step Length

This paper deals with the numerical cladistic taxonomy. A method for constructing evolutionary tree (method of maximal same step length) is proposed in the applications and practice of cladistic taxonomy. Its algorithm runs as follows: 1) According to the order of evolution, characters are coded with nonnegative integers, producing the original data matrix. 2) Calculate the same step coefficients Sij (i≠j) by the formula (3) and form the coefficient matrix. 3. Find the maximal value S_pq of the same step coefficients in the coefficient matrix. 4) According to the maximal same step length S_pq, the most recent common ancestor CTU, of CTUp and CTUq can be determinated by (2). 5) draw the cladistic edges of cladogram representing the evolutionary relationship from OTUT to OTUp and OTUq. If the number of CTUs in the data matrix≤2, go to (2), otherwise stop. An example of 6 species from the family Campanulaceae is given for illustration (See Table 1). In general case, the evolutionary length of the cladogram obtained by this method is shorter than that by monothetic and other methods. Its algorithm is easily performed and is especially suitable for computerizing.相似文献   

Systematic biostratigraphy: A solution to problematic classification systems in biostratigraphy

Systematic biostratigraphy is based on the exclusive use of monophyletic marker taxa. Non-monophyletic, or artificial, marker taxa have been shown to change biostratigraphic correlations, a situation that can be rectified by using systematics to ensure that marker taxa are monophyletic or natural. Both hypothetical and real examples demonstrate the validity of the methodology. The foraminiferal genera Praemurica and Parvularugoglobigerina are examples of non-monophyletic marker taxa. Cladistic results permit the reclassification of both genera, and a revision of foraminiferal biostratigraphy. Systematic biostratigraphy ensures the use of monophyletic marker taxa, preventing artificial classifications from hindering biostratigraphic correlations and producing more accurate, and stable, biostratigraphic zonations.     

菰属Zizania L.植物的分支分类研究

本文应用分支分类学中的最大同步法对全世界菰属Zizania L.及其有关属种进行定量分析研究其种系发生后所得出的分支树谱图上明显表示出法洛斯属Pharus Br.不应该与菰属、稻属Oryza L.等同位在稻族Oryzeae内,而应另立法洛斯族Phareae.菰属在稻族中独立出较进化的一支,当今称为菰亚族Zizaniinae.在菰属内全世界有4种.2亚种,其演化关系为菰Z.latifolia是最原始,由它分别向得克萨斯菰Z.texana及水生菰Z.aquatica演化,再由水生菰演化至沼生菰Z.palustris。     

龙胆属的系统发育分析

本文运用支序分类的原理和方法,对龙胆科龙胆属的属下等级进行了重新归类和系统发育分析。龙胆属是一个单系群,以3项近裔共性为归类依据。性状分析作了性状同源性分析和性状极性分析。性状极化主要以外类群比较、性状相关性及染色体资料为依据,其它方法,如生物重演律原则、地理递进原则以及孢粉形态等也被结合使用。分析结果,双蝴蝶属和蔓龙胆属被选择为外类群,71个性状被选择作为建立数据矩阵的基本资料。使用PAUP程序对矩阵进行了运算,得到4个最简约的谱系分支图,它们均具一致性系数0.637,支序长度为160步,f-比值范围为0.179～0.189,其中具最低f-比值的图被选作为类群归类和讨论亲缘关系的基础。在支序图上龙胆属归为15个组;其中5个组又划分为系,共包括23个系,其余组为单型组,故共有33个属下类群。一个严格的一致性谱系分支图总结了所有的一致点,从而支持了支序分析的结果。