A new scolenaspidid (Osteostraci, Vertebrata) from the Lower Devonian of Podolia, Ukraine

Anew osteostracan genus and species,Victoraspis longicornualis n. gen., n. sp., is described based on material from Rakovets’, present day Ukraine. This new taxon shares characters with the two generaStensiopelta Denison, 1951 andZychaspis Janvier, 1985. A phylogenetic analysis supports the position ofVictoraspis as the sister group to a monophyleticStensiopelta, while the interrelationships of the various species ofZychaspis are poorly resolved. A morphometric analysis is carried out in an attempt to further resolve the taxonomic affinity. This analysis groups all examinedZychaspis species closely together, and further supports the establishment ofVictoraspis as separate genus.      

REVISED CLASSIFICATION OF THE GENUS PACHYMENIA BASED ON MORPHOLOGICAL AND MOLECULAR CHARACTERS

Taxonomic discrimination in the genus Pachymenia (Rhodophyta) in New Zealand is based primarily on phenotypic characters of the thallus. The taxonomic problems raised by this classification method are due to highly variable thallus characters such as blade thickness, blade width, degree of thallus branching, and variation in anatomical characters. Delineation of species is further complicated by a lack of adequate knowledge about the responses of phenotype to environmental variation. There are currently three species recognized in this genus that are endemic to New Zealand: a prostrate species P. crassa , and two erect species, P. laciniata and P. lusoria. In this study, two approaches are used to investigate the current delineation of these species. Morphological and anatomical characters of field collected material and herbarium specimens from throughout the species' distributional ranges were quantified. Multivariate analyses were used to identify discrete phenotypic groups. Species relationships were further analyzed by quantifying the variation found within the internal transcribed spacer region (ITS) of the nuclear ribosomal DNA. The results obtained from both approaches will be discussed with regards to possible re-classification of species relationships within this genus. We suggest that the two erect species should be merged, and the currently recognized P. lusoria should be separated into at least two taxonomic groups.     

A review of the taxonomy of hawaiian pipturus (urticaceae) by anatomical and cytological evidence

The current taxonomic treatment of the genusPipturus (Urticaceae) in the Hawaiian Islands is evaluated in terms of anatomical and cytological criteria. This work revealed no distinct anatomical discontinuities between ten of the 13 species currently recognized. All taxa were found to be diploid with the chromosome complement of 14 pairs. The conclusion is advanced that the ingress of this genus to Hawaii probably involved a single introductory stock and that the current 13 species may be a large complex of intergrading races involving perhaps only two species.     

23种伞形科植物果实形态及其分类学意义

该实验采用徒手切片法对伞形科17属23种植物的果实进行了外部形态和解剖特征的观察,结果表明:伞形科果实有背腹压扁、两侧压扁和不压扁3种类型;侧棱有宽、有窄;油管的分布有棱槽单油管型和棱槽多油管型;花柱基多数为圆锥状,少数种的花柱基为扁平垫状;萼齿明显或不明显。通过进一步对属间和属内果实解剖特征的比较得出:(1)果实表面被钩刺或刚毛及果棱特征在属间差异明显,在属内表现出一致性,可作为伞形科属间分类的依据。(2)果实横切面的形状、胚乳腹面的凹凸以及萼齿的形态特征在属内种间的分类研究中有重要的意义。基于果实形态特征,编制了17属23种植物的分种检索表。     

Observations on the anatomy of Hermaea variopicta (Opisthobranchia: Ascoglossa)

The alimentary system, reproductive system and central nervous system of Hermaea variopicta (Costa) are described for the first time. Its gut resembles that of Hermaea bifida (Montagu), type species of the genus; the radula is considered in detail. Its diaulic reproductive system is described in morphological and functional terms. The central nervous system has three ganglia on the visceral loop. The anatomical evidence supports the opinion of Lemche & Thompson (1974) that Hermaeopsis Costa, former genus of H. variopicta, should be discarded. However, the division of the genus Hermaea into two subgenera, Hermaea and Placida, is not recommended. H. variopicta appears to be more primitive than H. bifida. In the discussion, the origin of hermaeid and stiligerid lines from a common ancestral stock is suggested, to which is added a new theory of the evolution of stiligerid penial styles.     

山茶属植物的染色体数目和核型

本文对已报道的(包括作者的研究)山茶属植物的染色体数目和核型作一简单的讨论,结合地理分布情况,提出由二倍体向多倍体进化可能是山茶属植物进化的一个重要途径。山茶属植物的核型多为Stebbins核型分类的“2A”型,表明山茶属植物是一个较原始的种系。本文中12种的染色体数目和2种的核型为首次报道。     

Molecular evolution of satellite DNA CLsat in lizards of the Darevskia species (Sauria: Lacertidae): correlation with species diversity

The structure and evolution of a satellite DNA family was examined in lizards from the genus Darevskia (family Lacertidae). Comparison of tandem units of repeated DNA (satDNA), CLsat, in all species from the genus Darevskia has shown that their variability is largely based on single-nucleotide substitutions, which constitute about 50 diagnostic positions underlying classification of the family into three subfamilies. Maximum differences between the subfamilies reached 25%. At this level of tandem unit divergence between the subfamilies, no cross-hybridization between them was observed (at 65 degrees C). The individual variability of one subfamily within the species was on average 5% while the variability between species consensuses within a subfamily was 10%. The presence of highly conserved regions in all monomers and some features of their organization show that satellites of all Darevskia species belong to one satDNA family. The organization of unit sequences of satellites CLsat and Agi also detected by us in another lizard genus, Lacerts s. str. was compared. Similarity that was found between these satellites suggests their relatedness and common origin. A possible pathway of evolution of these two satDNA families is proposed. The distribution and content of CLsat repeat subfamilies in all species of the genus was examined by Southern blotting hybridization. Seven species had mainly CLsatI (83 to 96%); three species, approximately equal amounts of CLsatI and CLsatIII (the admixture of CLsatII was 2-3%); and five species, a combination of all three subfamilies in highly varying proportions. Based on these results as well as on zoogeographic views on phylogeny and taxonomy of the Darevskia species, hypotheses on the evolution of molecular-genetic relationships within this genus are advanced.     

中国特有属——羌活属的系统分类研究

对伞形疠羌活属Ｎｏｔｏｐｔｅｒｙｇｉｕｍ Ｂｏｉｓｓｉｅｕ植物进行综合研究,包括花粉形态,叶气孔类型以及叶柄、果实的解剖观察,在此基础上讨论了羌活属的系统位置,并对该属的特征、种类分布作了修订,文中列出该属的分种检索表。其中叶柄、果实的形态解剖以及气孔类型均为首次报道。     

Anatomy of fishes of genus <Emphasis Type="Italic">Lampanyctus</Emphasis> (sensu lato), its taxonomic structure,and status in the Lampanyctini (Myctophidae) tribe system

An analysis of the structure of lateral musculature of the head and the basic skeletal elements was made in 14 species of genus Lampanyctus, which belong to all of its species groups. Although there are visible differences in the external morphology that are inherent in Lampanyctus from different species groups, stable anatomical differences were not revealed. Apparently, an important role in the evolution of Lampanyctus species was played by the process of paedomorphosis, which is expressed in a weak skeleton ossification, abnormal development or loss of its separate elements, a decrease in the maximum size of the body, and strong watering of body musculature. The absence of osteological differences between the species groups of Lampanyctus indirectly shows the unity of their origin and, therefore, confirms the hypothesis on the monophyly of this genus.     

Dental variation in the genus Pan

Dental measurements and 23 anatomical dental features are observed on 151 Pan troglodytes and 69 Pan paniscus of both sexes, preserved in the Museum of Tervuren (Belgium). Odontometric investigations confirm the reality of the two species in the genus Pan, but do not show any difference between subspecies in Pan troglodytes. Correspondence analysis demonstrates that the qualitative anatomical features are differently distributed in the two chimpanzee species.     

Phylogeography and bindin evolution in Arbacia, a sea urchin genus with an unusual distribution

Among shallow water sea urchin genera, Arbacia is the only genus that contains species found in both high and low latitudes. In order to determine the geographical origin of the genus and its history of speciation events, we constructed phylogenies based on cytochrome oxidase I and sperm bindin from all its species. Both the mitochondrial and the nuclear gene genealogies show that Arbacia originated in the temperate zone of the Southern Hemisphere and gave rise to three species in the eastern Pacific, which were then isolated from the Atlantic by the Isthmus of Panama. The mid-Atlantic barrier separated two additional species. The bindin data suggest that selection against hybridization is not important in the evolution of this molecule in this genus. Metz et al. in a previous publication found no evidence of selection on bindin of Arbacia and suggested that this might be due to allopatry between species, which obviated the need for species recognition. This suggestion formed the basis of the conclusion, widely spread in the literature, that the source of selection on sea urchin bindin (where it does occur) was reinforcement. However, the range of Arbacia spatuligera overlaps with that of two other species of Arbacia, and our data show that it is hybridizing with one of them. We found that even in the species that overlap geographically, there are no deviations from selective neutrality in the evolution of bindin.     

Key innovations in the evolution of Kranz anatomy and C4 vein pattern in Flaveria (Asteraceae)

Kranz anatomy and C(4) vein pattern are required for C(4) biochemical functioning in C(4) plants; however, the evolutionary timing of anatomical and biochemical adaptations is unknown. From the genus Flaveria, 16 species (C(3), C(4), intermediates [C(3)-C(4), C(4)-like]) were analyzed, novel anatomical and vein pattern characters were analyzed and key anatomical differences among photosynthetic groups were highlighted. A stepwise acquisition of anatomical and vein pattern traits prior to derived biochemistry was outlined on the basis of the phylogeny of Flaveria. Increased vein density represents a potential "precondition" contributing to lower ratios of photosynthetic tissues (mesophyll, bundle sheath) and precedes further anatomical and biochemical modifications observed in derived C(3)-C(4) intermediates. In derived Flaveria species, bundle sheath volume is modified through cell expansion, whereas mesophyll volume is altered through mesophyll cell expansion, reductions in the number of ground tissue layers, and increased vein density. Results demonstrated that key anatomical features of C(4) plants are also required for C(3)-C(4) biochemical intermediacy, and anatomical and biochemical alterations acquired during evolution of intermediacy may predispose a species for evolution of C(4) photosynthesis. C(4)-like species are similar to C(4) species, demonstrating that Kranz anatomy is fully evolved before complete C(4) biochemistry is achieved.     

On the origin and evolution of the genus Pedicularis L. in Xizang

The present paper is a preliminary research of the taxonomy, evolution, geographical distribution and origin of the species of the Genus Pedicularis L. in Xizang plateau. It may be summed up as follows: 1. There are 108 species of Pedicularis in Xizang, representing about 33% of the total species of the genus known in China. Among these species, there are 35 endemics, about 35.9% of the total species of the genus, this is especially true in Southeastern Xizang. Where there are 82.7% of total species of Xizang and 88% of endemics reported. 2. According to the relationships of the morphology of flower, leaf and evolution, the genus Pedicularis in Southeastern Xizang seems very active in evolution, because there is a wide range of flower types varying from the primitive alternate-toothless and opposite-toothed to the advanced beaked and long-tubed corolla-types. 3. There are almost all morphological types of the pollen, especially, the primitive particular tricolpate type is decidedly dominant, and the species with derived type of bicolpate pollen almost all belong to the beeked, long-tubed type of flowers; therefore, the evolutionary tendency and correlation between two types is very clear. According to above conditions, it may be considered that Southeastern Xizang is the evolutionary centre of the Genus Pedicularis L. 4. Basing upon the floristic-geographical analysis of neighbouring regions, we may consider that the members of genus Pedicularis in Xizang mainly come from the East, i.e. the mountains of the plateau frontier in Western Sichuan and Northwestern Yunnan. Finally, the floral relationships with other regions such as Buthan, Nepal, Xinjiang and Qinghai, Gansu, etc. are not so close, because the species in common are not verymany and usually widely distributed species.     

Leaf Anatomy of Fourteen Species in Carex Subgenus Indocarex (Cyperaceae)

Among the subgenera of the genus Carex, the subgenus Indocarex has been seldom studied in any respects, Its systematic position and its subdivision are still disputable. Leaf anatomy of 14 species in the subgenus lndocarex from China was studied. The anatomical characters are proved to be systematically valuable. (1) Characters of lamina transverse section: All leaves of these 14 species are dorsiventral. The outline mostly V-shaped, occasionally flat or nearly flat, with adaxial lateral rib in each half of lamina and some of them flanged. The cells of adaxial surface larger than those of abaxial surface, and the epidermal cells over veins usually smaller than others. Air-cavities between vascular bundles are well developed, and bulliform cells also well developed in most taxa. The vascular bundles are collaterai, bundle sheaths double-layered, and the outer sheath parenchymatous and the inner sheath fibrous. (2) Characters of lamina epidermis: The shape of the cell on both surfaces is generally rectangular, and the anticlinal wall of epidermal cell sinuous; stomata is paracytic, elliptic to oblong, rarely sub-circular; prickles occur on adaxial surfaces of certain species; papillae are only obvious on abaxial surface of C. moupinensis Franch. The characters of transverse section and epidermis of leaf blades of these 14 species differ from each other to certain degree, and closely related species are similar in anatomical characters. The anatomical characters of lamina are of value for classification at specific and sectional level of the subgenus Indocarex. Despite of the variation of these characters among species, a certain num ber of characters appears to be shared by the members of the subgenus, and some of the common characters are primitive. In addition, some gross morphological characters are common and primitive also. Therefore, the subgenus Indocarex may be primitive in the genus Carex. The anatomical and morphological characters of C. scaposa C. B. Clakre and C. densifimbriata Tang et Wang ex S. Y. Liang are distinct. The two species and their allies should be treated as section instead of subsection. The three species in the sectionPolystachyae share some anatomical characters and comprise a coherent group.     

Latitudinal trends in wood anatomy within species and genera: case study in Cornus s.l. (Cornaceae)

Latitudinal trends in wood anatomical characters in three Asiatic species of Cornus sensu lato (s.l.) were studied and compared with those for the whole genus based on an extensive sampling covering the specific distribution ranges and the generic data from a previous study. We studied 124 specimens of C. controversa growing between 31.5° and 45.3° N, 54 of C. kousa between 24.4° and 40.5° N, and 64 of C. macrophylla between 27.8° and 41.0° N. Characters studied were vessel element length, fiber length, vessel frequency, tangential vessel diameter, and vessel grouping index. At the species level no latitudinal trends were detected throughout the distribution ranges of the species. Neither tree size, altitude, nor climatic factors had a significant correlation with wood anatomical characters. In contrast, at the genus level, latitudinal trends were significant not just for the whole genus, but for both New and Old World species groups. At the genus level, latitude and three climatic factors all had a significant correlation with wood anatomical characters, but correlation coefficients with latitude were markedly high. The difference in latitudinal trends between the genus and species levels may be due to the radiation of Cornus along paleoclimatic gradients in the early Tertiary.     

Comparative vegetative anatomy and systematics of Cymbidium (Cymbidieae: Orchidaceae)

The genus Cymbidium (Orchidaceae) exhibits distinctive ecological diversification and occurs in terrestrial, epiphytic, and lithophytic life forms. One species, Cymbidium macrorhizon , lacks foliage leaves and has a strongly mycoparasitic existence. Correlation between habitat differentiation and anatomical characters was tested for 21 species of Cymbidium and its putative sister groups. Although hypostomaty characterizes the genus, C. canaliculatum shows amphistomaty. Ecological preference of this species indicates that amphistomaty is likely adapted to intensive insolation. Four types of subepidermal foliar sclerenchyma were found. Two forest floor species, C. goeringii and C. lancifolium as well as the mycoparasitic C. macrorhizon , do not have this sclerenchyma. In this genus, development of sclerenchyma is correlated with the degree of epiphytism. Palisade mesophyll evolved in Cymbidium section Cymbidium . As members of this section grow on isolated trees in tropical lowland forests or on rocks, the differentiation of palisade tissue is probably correlated with immigration to high light habitats. With the exception of C. macrorhizon , stegmata were found in leaves and stems of Cymbidium . Furthermore, a few epiphytic species have stegmata in their roots; this is a curious feature rarely found in vascular plants. Subterranean rhizomes characterize terrestrial species, while ageotropic roots are found in some epiphytic species. Cymbidium macrorhizon shows peculiar features such as degeneration of stomata, anomocytic stomata, and lack of stegmata and sclerenchyma. This set of character transformations is probably correlated with the evolution of mycoparasitic existence. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 383–419.     

基于叶绿体psaA和psbA基因的中国熊野藻属植物系统发育分析

以中国产熊野藻属Kumanoa的两个种, 绞扭熊野藻K. intorta (=绞扭串珠藻Batrachospermum intortum), 弯形熊野藻K. curvata (=弯形串珠藻B. curvatum)和其他6种淡水红藻为实验材料, 对其psaA和psbA基因进行扩增和测序, 并与GenBank中相近序列进行比对分析, 以贝叶斯法、最大似然法和邻接法分别构建了单基因和联合基因系统发育树. 结果表明, 3种方法构建的系统树具有相似的拓扑结构, 反映的系统发育关系基本一致, 熊野藻属中的两个种聚为一支, 与串珠藻属相分离, 支持该属的建立; 中国产的熊野藻属分子学研究结果与来自南美洲及澳洲的该属植物结果一致, 说明该属的建立具有广泛的地理适用性. 系统发育树聚类结果也明确反映了熊野藻属与串珠藻属较近的亲缘关系, 根据果胞枝形态特点, 推测熊野藻属进化地位晚于串珠藻属植物, 而早于顶丝藻目和红索藻目. 此外, 胶串珠藻与其他串珠藻组植物分离, 支持将其单独分组, 红索藻目植物与串珠藻目植物分离, 支持红索藻目的建立. 同时也表明psaA和psbA基因用于淡水红藻分析, 能够较好地反映其系统发育关系.       

根据形态和叶片微形态特征讨论无芒披碱草的归并

通过形态学观测和叶片解剖特征分析,比较了无芒披碱草、短芒披碱草及老芒麦3个近缘种的主要性状差异,以探讨无芒披碱草的系统分类归属.结果表明,在外部形态上无芒披碱草与短芒披碱草差异甚小,难以进行区分,但与老芒麦差异明显,是典型的种间关系;在叶片解剖上,无芒披碱草的绝大多数特征与短芒披碱草的一致或类同,可与老芒麦的却存在明显间断.故研究认为:无芒披碱草与短芒披碱草是同一个种,无芒披碱草应作为短芒披碱草的异名.     

A revision of Hyospathe (Arecaceae)

The neotropical palm genus Hyospathe includes two species, H. elegans and H. macrorhachis. Based on morphological, anatomical and palynological evidence, most of the names previously published in the genus have been synonymized into H. elegans. A detailed treatment of the variation and distribution of this broadly defined and widespread species is given.     

Patterns of host-plant choice in bees of the genus Chelostoma: the constraint hypothesis of host-range evolution in bees

To trace the evolution of host-plant choice in bees of the genus Chelostoma (Megachilidae), we assessed the host plants of 35 Palearctic, North American and Indomalayan species by microscopically analyzing the pollen loads of 634 females and reconstructed their phylogenetic history based on four genes and a morphological dataset, applying both parsimony and Bayesian methods. All species except two were found to be strict pollen specialists at the level of plant family or genus. These oligolectic species together exploit the flowers of eight different plant orders that are distributed among all major angiosperm lineages. Based on ancestral state reconstruction, we found that oligolecty is the ancestral state in Chelostoma and that the two pollen generalists evolved from oligolectic ancestors. The distinct pattern of host broadening in these two polylectic species, the highly conserved floral specializations within the different clades, the exploitation of unrelated hosts with a striking floral similarity as well as a recent report on larval performance on nonhost pollen in two Chelostoma species clearly suggest that floral host choice is physiologically or neurologically constrained in bees of the genus Chelostoma. Based on this finding, we propose a new hypothesis on the evolution of host range in bees.