中国29种和泰国1种卷柏科植物的叶形态学研究及其分类学意义

利用光学显微镜和体视显微镜对卷柏科Selaginellaceae中国产29种和泰国产1种植物的叶形态进行了宏观和微观观察。结果表明卷柏科植物在叶形态学方面表现出较高的一致性。(1)叶多为二形, 罕为一形, 无叶柄, 叶二形者侧叶多大于中叶, 外展或斜上, 中叶贴生于腹面茎上, 交互覆瓦状排成4列, 叶一形者则在茎上作螺旋状排列。(2)侧叶与中叶上表皮细胞形态相似, 近等径方形或长方形, 垂周壁平直、弓形或波状; 侧叶与中叶下表皮细胞形态也相似, 长方形或长条形, 垂周壁波状。(3)气孔类型为无规则型或放射型, 气孔多分布于中叶上表皮和侧叶下表皮中脉处。研究发现, 叶外形、叶表皮细胞形态及气孔分布特征等为中国卷柏科植物种间分类提供了重要的参考依据。 研究的有关种类可以依据下面这些特征进行分类: (1)叶为一形叶或二形; (2)叶在枝上着生为螺旋状或成对交互排列; (3)叶表皮细胞垂周壁为平直、弓形、深波状或浅波状; (4)叶上、下表皮细胞同形或异形; (5)气孔为无规则型或放射型; 以及(6)气孔在中叶和侧叶的上、下表皮上的分布等特征。     

中国薄叶卷柏复合群的物种划分

卷柏属(Selaginella)是石松类植物中最大的属, 也是分类难度较大的类群之一。该属的物种划分主要基于形态特征, 但许多近缘种在形态上很难区分。近年来, 已有大量分子证据被用于各植物类群的分类学研究, 但目前未发现一套适合卷柏属物种鉴定的分子标记。薄叶卷柏复合群(S. delicatula group)是卷柏属下鉴定较为困难的类群, 包括了薄叶卷柏(S. delicatula)、黑顶卷柏(S. picta)和瓦氏卷柏(S. wallichii) 3个物种, 主要分布于亚洲的热带和亚热带地区。为了探讨薄叶卷柏复合群内物种的亲缘关系和评估不同分子标记在卷柏属分类学研究中的应用价值, 本研究对该复合群物种进行广泛取样, 共收集到73个个体, 并选取3个叶绿体基因(rbcL, psbA和atpI)和2个核基因(26S nrDNA和pgiC)片段进行系统树的构建及叶绿体单倍型分析。研究发现, 基于叶绿体和核基因构建的系统发生关系存在冲突: 叶绿体基因树上薄叶卷柏个体分为两个分支(A和B), 薄叶卷柏B分支与薄叶卷柏A-S. picta分支呈姐妹关系, 并且rbcL单倍型分析结果也表明薄叶卷柏A和B两个分支存在明显分化; 而核基因结果则支持该复合群3个物种各自的单系性, 其中, S. delicatula分支与S. picta分支为姐妹群, S. wallichii与S. delicatula-S. picta分支为姐妹关系。在对复合群分布区大量标本的观察以及野外群体调查的基础上, 评估了植株茎和枝的分枝方式、孢子叶、营养叶(侧叶、中叶和腋叶)和孢子表面纹饰等形态性状的分类学价值。结果表明, 薄叶卷柏A和B分支的样本仅在植株分枝方式和大孢子表面纹饰上存在差异, 但无法依靠小孢子表面纹饰、孢子叶穗和营养叶形态等特征进行区分。基于现有证据, 薄叶卷柏复合群至少可划分为薄叶卷柏、黑顶卷柏和瓦氏卷柏3种, 但彻底澄清该复合群的物种划分还需要获取模式标本产地的材料和细胞学证据。最后, 建议在未来卷柏属的分类学研究集中于该属分类复杂的复合群, 结合使用形态学、细胞学、分子生物学(同时使用核基因和叶绿体分子标记)及地理分布等整合证据来进行物种划分。     

Phylogeny of extant genera in the family Characeae (Charales,Charophyceae) based on rbcL,sequences and morphology

Extant genera of Characeae have been assigned to two tribes: Chareae (Chara, Lamprothamnium, Nitellopsis, and Lychnothamnus) and Nitelleae (Nitella and Tolypella), based on morphology of the thallus and reproductive structures. Character analysis of fossil and extant oogonia suggest that Tolypella is polyphyletic, the genus comprising two sections, one in each of the two tribes. Eleven morphological characters and sequence data for the Rubisco large subunit (rbcL) were used to reconstruct the phylogeny of genera, including the two sections of Tolypella. Parsimony analysis of the rbcL data, with all positions and changes weighted equally, strongly supports the monophyly of the Characeae. The two Tolypella sections form a robust monophyletic group basal to the family. Transversion weighting yielded the same tree but with a paraphyletic Tolypella. The rbcL data strongly support monophyly of tribe Chareae but tribe Nitelleae is paraphyletic. Parsimony analysis of morphological data produced one unrooted tree consistent with monophyly of the two tribes; on this tree the Tolypella sections were paraphyletic. Combining morphological with rbcL data did not change the results derived from rbcL sequences alone. The rbcL data support the monophyly of the Characeae and Coleochaete, which together form a monophyletic sister group to embryophytes.     

Combined phylogenetic analysis in the Rubiaceae-Ixoroideae: morphology, nuclear and chloroplast DNA data

Parsimony analyses of morphology, restriction sites of the cpDNA, sequences from the nuclear, ribosomal internal transcribed spacer (ITS), and the chloroplast gene rbcL were performed to asses tribal and generic relationships in the subfamily Ixoroideae (Rubiaceae). The tribes Vanguerieae and Alberteae (Antirheoideae) are clearly part of Ixoroideae, as are some Cinchonoideae taxa. Pavetteae should exclude Ixora and allies, which should be recognized as the tribe Ixoreae. Heinsenia, representing Aulacocalyceae, is part of Gardenieae, as is Duperrea, a genus earlier placed in Pavetteae. Posoqueria and Bertiera and the taxa in the subtribe Diplosporinae should be excluded from Gardenieae. Bertiera and three Diplosporinae taxa are part of Coffeeae, while Cremaspora (Diplosporinae) is best housed in a tribe of its own, Cremasporeae. The mangrove genus Scyphiphora, recently placed in Diplosporinae, is closer to Ixoreae and tentatively included there. The combined analysis resulted in higher resolution compared to the separate analyses, exemplifying that combined analyses can remedy the incapability of one data set to resolve portions of a phylogeny. Twenty-four new rbcL sequences representing all five Ixoroideae tribes (sensu Robbrecht) are presented.     

Phylogeny and evolution of the Betulaceae as inferred from DNA sequences,morphology, and paleobotany

Phylogeny of the Betulaceae is assessed on the basis of rbcL, ITS, and morphological data. Based upon 26 rbcL sequences representing most “higher” hamamelid families, the Betulaceae are monophyletic, with Casuarinaceae as its sister group, regardless of whether the outgroup is Cunoniaceae, Cercidiphyllaceae, Hamamelidaceae, or Nothofagus. Within the Betulaceae, two sister clades are evident, corresponding to the subfamilies Betuloideae and Coryloideae. However, with only 13 phylogenetically informative sites, the rbcL sequences provide limited intra-subfamilial resolution. Internal transcribed spacer (ITS) sequences provided 96 phylogenetically informative sites from 491 aligned sites resulting in a single most parsimonious tree of 374 steps (consistency index = 0.791) with two major lineages corresponding to the two traditional subfamilies: Betuloideae (Alnus, Betula) and Coryloideae (Corylus, Ostryopsis, Carpinus, Ostrya). This arrangement is mostly consistent with those from rbcL and morphology and is greatly reinforced by analyses with the three data sets combined. In the Coryloideae, the Ostryopsis–Carpinus–Ostrya clade is well supported, with Corylus as its sister group. The sister-group relationship between Ostryopsis and the Carpinus–Ostrya clade is well supported by ITS, rbcL, and morphological data. Phylogenetic relationships among the extant genera deduced by these analyses are compatible with inferences from ecological evolution and the extensive fossil record.     

Phylogeny and morphology of Nemalionopsis shawii (Thoreales,Rhodophyta), a new generic record from mainland China

The freshwater red alga Nemalionopsis shawii Skuja is first reported for mainland China from specimens collected in Guangdong and Yunnan Province. Morphological observations and molecular sequences of rbcL and cox1 genes were used to identify and analyze the phylogenetic position of the samples. Samples from China formed a monophyletic clade with other N. shawii samples from Japan, Indonesia, and Nepal with robust support values. The pairwise genetic distances for N. shawii between the samples from China and other samples were 0.2–1.5% and 1.0–2.4% for rbcL and cox1, respectively. Both male and female reproductive structures were observed in the specimens from Guangdong, but only monosporangia in the specimen from Yunnan. The samples from China increase the diversity of morphological measurements for N. shawii. The discovery of this genus in mainland China results in a new record of a freshwater red alga for this country.     

Phylogeny and morphology of the freshwater red alga Nemalionopsis shawii (Rhodophyta,Thoreales) from Nepal

Phylogenetic relationships and morphological characters are presented for a population of Nemalionopsis shawii Skuja collected from Nepal. Molecular data (sequences of rbcL and cox1) were generated and morphological characters were described in detail. The rbcL sequence analyses showed that specimens from Nepal are most similar to N. shawii from Indonesia and Japan and that these entities form a clade with high support (>95% bootstrap and 0.95 posterior probability). The cox1 barcode sequence, however, only had 90.9–91.9% identity with specimens of N. shawii from Hawaii. The rbcL sequence of the specimen from Nepal was positioned in a clade having sequence identity of 99.3–99.7% with three samples: N. shawii from Indonesia and two from Japan identified as N. tortuosa. The comparison of morphological characters of Nemalionopsis from Nepal allowed unequivocal identification with N. shawii. Identifications from previous studies using molecular data were mistaken since most reports of N. shawii are actually of N. tortuosa or vice‐versa. This confusion of names presumably occurred because most specimens previously sequenced were from culture collections or from ‘Chantransia’ stages. Small tufts of ‘Chantransia’ stage were observed growing epiphytically on gametophytes and on the basal system. Carpogonia and spermatangia were fully described in specimens from Nepal. Monosporangia were not observed, whereas carposporangia were unequivocally described for the first time in the genus. An unusual flat strap‐like basal system was observed, interpreted as an additional mode of maintenance in nature under unfavorable environmental conditions.     

Phylogeny of the Procyonidae (Mammalia: Carnivora): molecules, morphology and the Great American Interchange

The Procyonidae (Mammalia: Carnivora) have played a central role in resolving the controversial systematics of the giant and red pandas, but phylogenetic relationships of species within the family itself have received much less attention. Cladistic analyses of morphological characters conducted during the last two decades have resulted in topologies that group ecologically and morphologically similar taxa together. Specifically, the highly arboreal and frugivorous kinkajou (Potos flavus) and olingos (Bassaricyon) define one clade, whereas the more terrestrial and omnivorous coatis (Nasua), raccoons (Procyon), and ringtails (Bassariscus) define another clade, with the similar-sized Nasua and Procyon joined as sister taxa in this latter group. These relationships, however, have not been tested with molecular sequence data. We examined procyonid phylogenetics based on combined data from nine nuclear and two mitochondrial gene segments totaling 6534bp. We were able to fully resolve relationships within the family with strongly supported and congruent results from maximum parsimony, maximum likelihood, minimum evolution, and Bayesian analyses. We identified three distinct lineages within the family: a (Nasua, Bassaricyon) clade, a (Bassariscus, Procyon) clade, and a Potos lineage, the last of which is sister to the other two clades. These findings, which are in strong disagreement with prior fossil and morphology-based assessments of procyonid relationships, reemphasize the morphological and ecological flexibility of these taxa. In particular, morphological similarities between unrelated genera possibly reflect convergence associated with similar lifestyles and diets rather than ancestry. Furthermore, incongruence between the molecular supermatrix and a morphological character matrix comprised mostly of dental characters [Baskin, J.A., 2004. Bassariscus and Probassariscus (Mammalia, Carnivora, Procyonidae) from the early Barstovian (Middle Miocene). J. Vert. Paleo. 24, 709-720] may be due to non-independence among atomized dental characters that does not take into account the high developmental genetic correlation of these characters. Finally, molecular divergence dating analyses using a relaxed molecular clock approach suggest that intergeneric and intrageneric splits in the Procyonidae mostly occurred in the Miocene. The inferred divergence times for intrageneric splits for several genera whose ranges are bisected by the Panamanian Isthmus is significant because they suggest diversification well precedes the Great American Interchange, which has long been considered a primary underlying mechanism for procyonid evolution.     

There it is! Fusarium pseudograminearum did not lose the fusaristatin gene cluster after all

Fusarium pseudograminearum is a significant pathogen of cereals in arid regions worldwide and has the ability to produce numerous bioactive secondary metabolites. The genome sequences of seven F. pseudograminearum strains have been published and in one of these strains, C5834, we identified an intact gene cluster responsible for biosynthesis of the cyclic lipopeptide fusaristatin A. The high level of sequence identity of the fusaristatin cluster remnant in strains that do not produce fusaristatin suggests that the absence of the cluster evolved once, and subsequently the resulting locus with the cluster fragments became widely dispersed among strains of F. pseudograminearum in Australia. We examined a selection of 99 Australian F. pseudograminearum isolates to determine how widespread the ability to produce fusaristatin A is in F. pseudograminearum. We identified 15 fusaristatin producing strains, all originating from Western Australia. Phylogenetic analyses could not support a division of F. pseudograminearum into fusaristatin producing and nonproducing populations, which could indicate the loss has occurred relatively recent.     

Reinstatement of Grateloupia subpectinata (Rhodophyta, Halymeniaceae) based on morphology and rbcL sequences

Morphological observations and molecular analyses of the north‐western Pacific species of the red algal genus Grateloupia (Halymeniaceae) indicate the presence of an entity, which is somewhat similar in gross morphology to G. asiatica Kawaguchi et Wang but is distinguished from the latter species by some morphological features. These include: (i) a somewhat fleshy texture; (ii) wider and much thicker (4.5–10 mm wide and up to 1300 μm thick) axes, of which an inner cortex consists of more (6–9) cells; (iii) generally longer (up to 17 cm), marginal and surface proliferations that are clearly constricted (terete) at bases; and (iv) much elongated, oblong auxiliary cells. Phylogenetic analysis using the ribulose‐l,5‐bisphosphate carboxylase/ oxygenase (rbcL) gene of G. asiatica and the alga in question shows them to be distantly related and strongly supports the differentiation of these two entities at the species level. Judging from the literature, this entity is actually Grateloupia subpectinata Holmes, which has been placed into synonymy under G. asiatica [as G. filicina (Lamouroux) C. Agardh] or G. prolongata J. Agardh in previous reports, and therefore the Holmes name is reinstated.     

Phylogeny of the Caninae (Carnivora): Combining morphology,behaviour, genes and fossils

Phylogenetic relationships among 36 Recent and 42 extinct species of the Caninae (Canidae) were analysed, based on 360 morphological, developmental, ecological, behavioural and cytogenetic characters and 24 mitochondrial and nuclear markers. Primary phylogenetic analyses were accompanied by experimental analyses based on various combinations of data partitions and taxon samples. Leptocyon was recovered as a paraphyletic stem lineage of the Caninae; monophyly/paraphyly of the fox‐like canids (Vulpini) remains uncertain; Urocyon and Metalopex form a clade, possibly sister to all non‐Leptocyon canids; Otocyon, Nyctereutes and Nurocyon form a clade; dog‐like canids (Canini) are monophyletic (with South American Cerdocyonina and Afro‐Holarctic Canina); all South American hypercarnivores (Canis gezi, Protocyon, Speothos, Theriodictis) form a clade, close to Chrysocyon and Dusicyon; Canis arnensis, C. ferox, C. thooides, C. lepophagus and Eucyon spp. are basal to the Canina; Lycaon is an isolated African hypercarnivore; Cuon and its relatives (Xenocyon, possibly also Canis antonii, C. falconeri and Cynotherium) form a clade close to Canis s. str.; C. edwardii–C. etruscus–C. mosbachensis–C. palmidens–C. variabilis and hypercarnivorous Canis armbrusteri–C. dirus clades belong to Canis s. str. As the highly homoplastic morphological characters connected to dietary biology are the prominent characters available for the key fossil species, we conclude that macroevolutionary and palaeoecological analyses of the extinct and extant Caninae were to some extent compromised by the phylogenies used.     

Phylogeny of Podocarpaceae: comparison of evidence from morphology and 18S rDNA

Maximum parsimony analyses of the genera of Podocarpaceae were conducted using sequence data from 18S ribosomal DNA. Trees from sequence, morphological, and combined data differ in taxon arrangement, but are similar in that Podocarpus sensu lato and Dacrydium s.l. are unnatural, while Podocarpaceae (including Phyllocladus) are monophyletic. The clade Microcachrys + Microstrobos is recognized in all analyses, but its placement differs, i.e., nested among other scale-leaved taxa in the morphological analysis, but associated with Nageia and other tropical genera in the sequence analyses. Trees from combined data reflect this ambiguity. Podocarpus sensu stricto is paraphyletic according to most trees. Inferences of plesiomorphic character states within the family are largely consistent between analyses and support the view that prototypical podocarps had bifacial leaves, cones with several fertile cone scales, and large epimatia (cone scales) that covered the inverted ovules.     

南五味子属花的形态及其系统学意义

借助扫描电镜观察了南五味子属(Kadsura)中黑老虎(K.coccinea)、南五味子(K.japonica)和狭叶南五味子(K.angustifolia)雄花和雌花的形态发生过程, 三种植物花发育早期相似而发育后期出现分异。根据花形态发生早期的相似性, 支持南五味子属为单系起源;根据花形态发生后期的分异状态, 支持将南五味子属分为离蕊南五味子亚属(Subgenus Cosbaea)和南五味子亚属(Subgenus Kadsura)。借助扫描电镜观察了短梗南五味子(K.borneensis)和披针叶南五味子(K.lanceolata)花的形态, 将南五味子和狭叶南五味子的花与短梗南五味子和披针叶南五味子的花比较, 赞成在南五味子亚属下设南五味子组(Section Kadsura)和南洋南五味子组(Section Sarcocarpon)。根据在狭叶南五味子中观察到的两性花痕迹和在五味子属(Schisandra)东亚五味子(S.elongata)花中观察到的两性花, 本文认为现存五味子科(Schisandraceae )植物的单性花可能由具两性花结构的祖先演化而来。根据五味子科植物柱头与八角科(Illiciaceae)植物柱头的相似性, 不支持将五味子科从八角目(Illiciales)中分出而成立五味子目(Schisandrales)的观点。     

Phylogeny of decapods: moving towards a consensus

Although the recognition of four broad groups within Decapoda – natantians, macrurans, anomurans and brachyurans – has long been a staple of textbooks and even the primary taxonomic literature, a precise resolution of phylogenetic relationships within the order has proved more difficult. Indeed, there have been as many schemes of decapod taxonomy and phylogeny as there were experts who wished to offer an opinion. In this decade, utilization of explicit cladistic methods of analysis and the application of molecular techniques have produced a series of clear hypotheses concerning the relationships within many of the groups of Decapoda. It is apparent that earlier conflicts of opinion can be related in part to the implicit problems of dealing with paraphyletic groups near the base of the tree that are too broadly defined by only general or plesiomorphic features. Comprehensive morphological analyses of both fossil and living forms, with attention being paid to defining synapomorphies, can lead to resolution of old controversies. Molecular techniques hold great promise towards providing further resolution, but currently suffer from insufficiencies of sampling. Nevertheless, where once there was chaos and vexation, there is now some enlightenment. The situation can only improve, but the broad outlines of decapod deep history are already emerging.     

Phylogeny of the Braconinae (Hymenoptera: Braconidae): A new tribal order!

Generic relationships within the parasitoid wasp subfamily Braconinae are assessed based on a molecular phylogenetic analysis of four gene fragments: mitochondrial cytochrome c oxidase subunit I, 16S rDNA, nuclear 28S D2-D3 rDNA and elongation factor 1-alpha. Our results support the recognition of Aphrastobraconini, Braconini and Coeloidini plus three new tribes: Compsobraconini tribus nov ., Tropobraconini tribus nov . and Virgulibraconini tribus nov . The first of these new tribes is restricted to the New World; the second includes the Old World genera Tropobracon Cameron, Trispinaria Quicke and Grangerbracon Samartsev and Belokobylskij and possibly others, whereas the third comprises the Australian genus Virgulibracon Quicke, plus several other described and undescribed Australian genera. Consistent placement of Amyosoma Viereck with members of the Virgulibraconini tribus nov . is discussed, whereas Amyosoma is left currently unplaced. A preliminary key to tribes is presented, and the characters used to differentiate between Aphrastobraconini and Braconini are revised. Megacoeloides Quicke was never recovered with Coeloides, the type genus of Coeloidini, so it is treated as Braconinae incertae sedis. By combining molecular and morphological traits, nearly all valid genera are assigned to tribes, and the possible relationships of the remainder are discussed. Alienoclypeus Shenefelt, 1978 is synonymised with Atanycolus Förster, 1862 (Atanycolus insolitus (Shenefelt) comb. nov .). Several new genera have been revealed and will be described elsewhere.     

Hymenidium pilosum (Apiaceae) is a synonym of H. apiolens based on morphology and molecular data

Hymenidium apiolens and H. pilosum have been recorded to co-occur in the Himalayas, and it was found difficult to distinguish between them in the field. In this study, we reconstructed the phylogeny and estimated the genetic distance between individuals of H. apiolens, H. pilosum and related species based on nuclear ITS sequences, and rpl16 and rps16 introns, to determine the relationship between H. apiolens and H. pilosum. The analyses suggest that H. apiolens and H. pilosum are nested together, and that the ratio of genetic distance between them is smaller than that between individuals of Chamaesium spatuliferum, Hansenia forbesii or Ligusticum acuminatum. Furthermore, we found similar morphological characteristics of bracteoles, rays, petals and mericarps in H. apiolens and H. pilosum. Consequently, both molecular and morphological evidence supports that Hymenidium pilosum is a synonym of H. apiolens.