湖南益阳奥陶系五峰组—志留系周家溪群笔石

为响应国际地层委员会奥陶系分会的要求,实现扬子区与江南区奥陶纪晚期—志留纪早期生物地层精时对比,选取位于江南斜坡带的湖南益阳南坝剖面作为研究对象,对志留系底部Parakidograptus acuminatus带笔石进行了系统的研究。剖面内五峰组岩性为黑色页岩,与上覆周家溪群下组整合接触,地层连续无沉积间断。通过连续不间断采集笔石标本,在研究剖面共识别出笔石6属8种,包括:Parakidograptus acuminatus,Normalograptus elegantulus,Nor. mirnyensis,Metabolograptus persculptus,Neodiplograptus parajanus,Neo. guantangyuanensis,Petalithus hamus,Streptograptus cyclodontus。依据获取的笔石标本,初步识别出Metabolograptus persculptus带和Parakidograptus acuminatus带,确定研究剖面时代为晚奥陶世赫南特期—早志留世鲁丹期。     

A Review on the Taxonomic, Evolutionary and Phytogeographic Studies of the Lotus Plant (Nelumbonaceae: Nelumbo)

Nelumbo Adans. （Nelumbonaceae） is an important member of the early-diverging eudicots. It contains two extant species： N. nucifera Gaertn. （the Sacred lotus）, distributed in Asia and Australia and N. lutea Willd. （the American lotus）, occurring in North America. This paper reviews the taxonomic, evolutionary and phytogeographic studies of the genus Nelumbo, and also raises scientific questions about it in further paleobotanic research. There are about 30 fossil species of Nelumbo established since the Early Cretaceous. Based on fossil studies, the ancestors of the extant N. nucifera and N. lutea are respectively considered to be N. protospeciosa from the Eocene to Miocene of Eurasia, and N. protolutea from the Eocene of North American. However, molecular systematic studies indicate that N. nucifera and N. lutea are probably split from a common ancestor during the Late Miocene to Early Pliocene, or even the Pleistocene, rather than separate relicts from extinct species on different continents. The characters of lotus stomatal development, seedling morphology as well as its flowering, pollination and fertilization in air reveal that it evolves from the land plants. Fossil data of Nelumbo indicates that the genus first occurs in mid-latitude area of Laurasia in the Early Cretaceous, then becomes widespread in North America and Eurasia and expands into Africa and South America during the Late Cretaceous; the genus probably colonizes the Indian Subcontinent from Asia during the Early Eocene after the collision of India and the Asian plates; the genus becomes extinct in Europe, but survives in Asia and North America during the Quaternary Ice Age, and later forms the present East Asia and North Australia-North America disjunctive distribution.     

鳞侧尖柳珊瑚Paracis squamata(Nutting,1910)(八放珊瑚亚纲:丛柳珊瑚科)的形态学和系统发育研究

2014年自雅浦海沟附近的一座海山通过水下无人遥控潜水器获得3株八放珊瑚样本,通过对其珊瑚虫和骨片观察,并结合线粒体错配修复蛋白基因(mtMutS)的测序分析,进行了分类学和系统发育研究。结果显示,3株八放珊瑚均为鳞侧尖柳珊瑚Paracis squamata (Nutting,1910)。该物种主要特征为具有鳞片状的萼部骨片和无规则板状的共肉组织外层骨片。在基于mtMutS基因构建的系统发育树中,鳞侧尖柳珊瑚与侧尖柳珊瑚未定种(Paracis sp.)以高置信度聚在一起,侧尖柳珊瑚属(Paracis)和鳞尖柳珊瑚属(Lepidomuricea)以高支持率形成姐妹枝。本文对鳞侧尖柳珊瑚的形态学特征进行了全面研究,首次描述了共肉组织内层骨片的特征,揭示侧尖柳珊瑚属与鳞尖柳珊瑚属具有较近的亲缘关系。     

中国近海豆滨螺属Peasiella(腹足纲,滨螺科)两物种的分类学研究

在对历年来在中国近海采集的滨螺科(Littorinidae)贝类标本进行系统整理和研究的过程中,鉴定出隶属于豆滨螺属Peasiella的2个物种:波部豆滨螺Peasiella habei D. ReidMak, 1998和罗豆滨螺Peasiella roepstorffiana Nevill, 1885。标本采自中国山东省及海南省沿海区域,栖息于潮间带及浅海的礁石上。本文对2个物种的贝壳形态、齿舌特征及地理分布等方面进行了详细描述,并对其分类地位以及主要鉴别特征进行了讨论,提出齿舌数量及排列方式即齿式为该属物种区分的重要依据。同时,将张氏马蹄螺Trochus zhangi Dong,2002归于罗豆滨螺Peasiella roepstorffiana Nevill,1885的次异名。     

A preliminary phylogenetic analysis of Luidia (Paxillosida: Luidiidae) from Chinese waters with cytochrome oxidase subunit I (COI) sequences

Luidia Forbes (Paxillosida: Luidiidae) are common soft bottom sea stars with 49 described species. Because of substantial morphological diversity, the taxonomy of the genus is complex and hasn’t been resolved definitely. In order to resolve general taxonomic issues, and determine species boundaries and phylogenetic relationships within the genus Luidia, the sequences of cytochrome oxidase subunit I (COI) gene from 24 specimens of Luidia, belonging to eight taxa in Chinese waters, were studied. Three sequences of two species in genus Luidia from GenBank were used to analyze the phylogenetic relationships. The molecular phylogeny exhibited three main clades, each with strong bootstrap support: Clade A including Luidia quinaria from the Sea of Japan; Clade B including seven nominal species (L. quinaria von Martens, L. yesoensis Goto, L. changi Liu, Liao and Li, L. orientalis Fisher, L. avicularia Fisher, L. longispina Sladen and L. hardwicki Gray) from Chinese waters; and Clade C including L. maculata Müller & Troschel from Chinese waters. Our molecular phylogeny results support the morphological Quinaria-Group and Alternata-Group assigned by Döderlein. Seven nominal species we sampled do not exhibit genetic distances that are large enough to recognize them as separate species. Cryptic species may exist in’ Luidia quinaria’ from the Yellow Sea and the Sea of Japan. Meaningful morphological characters need further investigation in Luidia.     

Ocnus sacculus new species (Echinodermata: Holothuroidea), a brood‐protecting holothurian from southeastern New Zealand

A new species in the dendrochirotid holothurian genus Ocnus sensu lato is described from approximately 600 m depth in Taiaroa Canyon, off Otago, New Zealand. Ocnus sacculus new species has single rows of tubefeet only in the 3 ventral radii. Body‐wall ossicles consist of cups, knobbed 4‐holed buttons, and multi‐layered plates averaging 0.7 mm in diameter. Three brood pouches lie anteriorly on the inner surface of the body wall in 3 dorsal interradii; the mid‐dorsal pouch is largest. The pouches apparently have no permanent contact with the exterior; presumably birth takes place by rupture of the body wall.     

Observations on Gastrotricha from a sandy beach in southeastern Australia,with a description of Halichaetonotus australis sp. nov. (Gastrotricha,Chaetonotida)

Several species of Gastrotricha were found among samples of nematodes extracted from a sandy ocean beach, South Broulee beach, in southeastern Australia. One of these Gastrotricha turned out to be a species new to science which is described as Halichaetonotus australis sp. nov. in this study. Although the spines of the hydrofoil scales resemble those of the cosmopolitan H. aculifer, a distinctive feature of the new species is the presence of three prominent posterior dorsal spines. These are exaggerations of the keels found on the dorsal overlapping scales that cover the dorsal surfaces of the head, neck, and trunk. The spines are almost as long as the rami of the terminal furca. H. australis sp. nov. also resembles H. marivagus, but differs in lacking both a cephalion and hypostomion. Freeze drying is introduced as a preparation method for scanning electron microscopy of Gastrotricha.     

Testing use of mitochondrial COI sequences for the identification and phylogenetic analysis of New Zealand caddisflies (Trichoptera)

We tested the hypothesis that cytochrome c oxidase subunit 1 (COI) sequences would successfully discriminate recognised species of New Zealand caddisflies. We further examined whether phylogenetic analyses, based on the COI locus, could recover currently recognised superfamilies and suborders. COI sequences were obtained from 105 individuals representing 61 species and all 16 families of Trichoptera known from New Zealand. No sequence sharing was observed between members of different species, and congeneric species showed from 2.3 to 19.5% divergence. Sequence divergence among members of a species was typically low (mean = 0.7%; range 0.0–8.5%), but two species showed intraspecific divergences in excess of 2%. Phylogenetic reconstructions based on COI were largely congruent with previous conclusions based on morphology, although the sequence data did not support placement of the purse‐cased caddisflies (Hydroptilidae) within the uncased caddisflies, and, in particular, the Rhyacophiloidea. We conclude that sequence variation in the COI gene locus is an effective tool for the identification of New Zealand caddisfly species, and can provide preliminary phylogenetic inferences. Further research is needed to ascertain the significance of the few instances of high intra‐specific divergence and to determine if any instances of sequence sharing will be detected with larger sample sizes.     

Cambrian Fossil Embryos from Western Hunan,South China

The exquisitely preserved fossil embryos of Markuelia recovered from the limestones of the Middle Cambrian Haoqiao Formation and Upper Cambrian Bitiao formation in western Hunan, South China are described and illustrated in detail for the first time.A new species Markuelia elegans sp.nov.is established based mainly on embryos from the Upper Cambrian.A few of animal's resting eggs,which are comparable with those of the Ediacaran Doushantuo Formation,have been also found in the Upper Cambrian of western Hu...     

甲藻(Dinophyta)凯伦藻科(Kareniaceae)的分类学研究与展望

凯伦藻科(Kareniaceae)是甲藻门中较新建立的一个科。凯伦藻科种类广泛分布于全球海域,目前已报道3属30个种。由于该科大部分种类频发藻华,严重威胁近海生态安全和水产养殖,因而备受关注。自20世纪90年代起,我国沿岸也逐渐成为凯伦藻藻华的重灾区,凯伦藻曾引发我国最严重的几次藻华事件。本文对本科种类分类学特征进行详细描述,翻译其中文名,编制属、种分类检索表,以期为我国凯伦藻生物多样性研究以及凯伦藻藻华防治提供基础而必要的种源信息。