南海织纹螺属三新纪录(腹足纲,织纹螺科)

在整理分类近年来在海南岛和南沙群岛采集的织纹螺科标本时,鉴定出属于织纹螺属的3个中国新纪录种:1)巴氏织纹螺Nassarius (Zeuxis)barsdelli(Ladd,1976);2)蛛形织纹螺Nassarius(Zeuxis)algidus(Reeve,1853);3)杰克逊织纹螺Nassarius(Niotha)jacksonianus(Quoy & Gaimard,1833).3新纪录种分属于Zeuxis 和Niotha两亚属,它们主要生活于潮间带至浅海或百余米水深的泥质沙或沙质海底.     

织纹螺科一新种记述(腹足纲,前鳃亚纲,新腹足目)

在整理浙江沿海织纹螺科标本时,经传统方法和分子生物学方法鉴定发现1新种,即拟半褶织纹螺Nassarius (Zeuxis) semiplicatoides sp.nov..隶属于腹足纲、新腹足目、织纹螺科、织纹螺属、Zeuxis亚属.文中对新种的形态特征和栖息环境进行了记述,并与近似种进行了比较讨论.     

基于16S rRNA基因序列对织纹螺属的分子系统学分析

研究利用线粒体16S rRNA基因序列片段,对织纹螺属6亚属11种动物进行分子系统学分析。结果显示,种内遗传距离(0～0.007)与种间遗传距离(0.019～0.088)无重叠,这表明线粒体16S rRNA基因能较好地反映织纹螺种间的亲缘关系; 而亚属内遗传距离(0.018～0.031)与亚属间遗传距离(0.028～0.083)存在重叠,表明线粒体16S rRNA基因不能对一些贝壳形态相似的亚属进行区分。同时,确定了疑难种灰白织纹螺Nassarius(Zeuxis)canaliculatum的分类地位,并与相似种西格织纹螺N.(Z.)siquijorensis进行了对比; 确认了秀丽织纹螺Nassarius(Hima)festivus应属于Hima亚属;建议保留单型亚属Varicinassa的有效性。     

基于16SrDNA序列片段探讨织纹螺的系统发生关系

通过对细肋织纹螺、红带织纹螺、半褶织纹螺、拟半褶织纹螺、纵肋织纹螺和秀丽织纹螺等6种织纹螺属Nassarius动物线粒体16SrDNA的部分序列以及GeneBank中西格织纹螺和秀丽织纹螺2条同源序列的分析,使用MAGE软件构建了系统发生树(NJ树和ME树),探讨了这7种织纹螺种间以及亚属间的系统发生关系。结果表明,本研究所涉及的织纹螺16SrDNA序列能较好的反映织纹螺种间和亚属间的亲缘关系,16SrDNA可用于织纹螺近缘种类的系统学研究;系统树均支持将拟半褶织纹螺作为一独立种的观点;Reticunassa亚属的种和Varicinassa亚属的种亲缘关系相对前者与Zeuxis亚属的种近。     

半褶织纹螺(Nassarius semiplicatus)及其生活环境中分离培养的细菌毒性测试与种类分析

在中国沿海地区,因食用织纹螺导致的中毒事件时有发生.最近的研究表明,河豚毒素及其衍生物是织纹螺中主要的致毒成分.但是,对于织纹螺中河豚毒素的来源还不清楚.[目的]本研究尝试分离、培养和鉴定织纹螺及其生活环境中的细菌,并对其毒性进行分析,为探明织纹螺中河豚毒素的可能来源提供科学依据.[方法]先后于2006年6月13日和19日在江苏省盐城采集织纹螺样品,应用小鼠生物法对织纹螺样品的毒性进行了测试;从织纹螺体内及其生活环境中分离细菌,并选择部分菌株进行了室内培养;以直接竞争酶联免疫分析方法(ELISA)对培养菌株中的河豚毒素进行了检测;通过对细菌16S核糖体DNA(rDNA)部分序列的测定,对有毒菌株进行了初步的种灯分析.[结果]实验结果表明,采集的织纹螺为半褶织纹螺,两次采集样品的毒性分别为247 MU(mouse unit,小鼠单位)和270MU/100g组织(湿重).对14个菌株进行了毒性检测,其中有毒细菌9株.产毒菌株的毒性普遍较低,毒性范围为15～96 ng/g.有毒菌株核糖体序列与弧菌(Vibrio)、希瓦氏菌(Shewanella)、动性球菌(Planococcus)、海单胞菌(Marinomonas)、发光杆菌(Photobacterium)等菌属有较高的相似性,可能具有较近的亲缘关系.[结论]研究发现半褶织纹螺体内及其生活环境中存在能够产生河豚毒素的细菌,说明织纹螺中的河豚毒素可能与其体内及其生活环境中的细菌有关,有必要进行深入研究.     

嫁(虫戚)属2种的齿舌形态差异分析

在光镜和电镜下对嫁(虫戚)(Cellana toreuma)和斗嫁(虫戚)(C.grata)的齿舌形态进行观察比较。2种嫁(虫戚)的齿式都为1.1.0.1.1,即具有1枚侧齿和1枚缘齿,缺乏中央齿。齿舌前端都有1小段弯曲,齿片排列松散且存在明显的磨损现象。嫁(虫戚)和斗嫁(虫戚)的侧齿形状很相似,侧齿呈镰刀型且具1个齿尖,基部近似三角形且具突起,尖齿部分细长。两种嫁(虫戚)的缘齿存在一定的差异,嫁(虫戚)缘齿具3个齿尖,第2尖齿靠近第3尖齿。斗嫁(虫戚)缘齿具2个齿尖且比较细长,第2尖齿靠近缘齿基部。本文用17个参数对这两种嫁(虫戚)的齿舌带及其前中后3段上的齿片进行了测量比较,发现斗嫁(虫戚)齿舌带的长宽比明显大于嫁(虫戚)齿舌带的长宽比,即斗嫁(虫戚)的齿舌带显得更加细长。齿舌带前、中、后3段各比例参数的值存在一定的关系,即中段大于前段、中段大于后段。据此认为用齿舌作为2种嫁(虫戚)的分类依据是可行的。     

两种石磺齿舌形态差异分析

显微观察了瘤背石磺(Onchidiumstruma)和石磺(O. verruculatum)齿舌的形态结构。运用差异系数法对两种石磺齿舌参数进行比较分析。利用SPSS10.0对瘤背石磺、石磺齿舌参数(齿舌长、齿舌头宽、齿舌中宽、齿舌尾宽、横列数、每排最少齿片数和每排最多齿片数)与个体参数(体长、体宽、体高、足长、足宽和体重)作回归分析。结果表明,两种石磺齿舌都很发达,外观呈长统靴状;齿片排成许多横列,每一横列均有中央齿一枚,侧齿若干无缘齿;两种石磺的齿舌头宽、齿舌中宽和齿舌尾宽差异极显著,但差异系数小于1.28,认为两种石磺的齿片形态存在明显的种间差异,但齿舌参数不适合作为石磺属贝类的分类依据;瘤背石磺的体宽和石磺的体重在评估各自齿舌生物学性状方面起到比较重要的作用。     

埃及吹绵蚧与捷氏吹绵蚧（半翅目，蚧次目，绵蚧科）的形态特征比较

埃及吹绵蚧Icerya aegyptiaca (Douglas）与捷氏吹绵蚧I. jacobsoni Green隶属半翅目绵蚧科Monophlebidae吹绵蚧属Icerya,是我国南方常见害虫。因二者在各发育阶段均覆盖蜡质分泌物,形态上难以区分,常被混淆。本文通过对这2种蚧虫的寄主植物、活虫体形态特征、玻片标本的显微形态特征等方面进行详细比较,以期为这2种害虫的准确鉴定和监测防控提供依据。     

中国有厣陆生贝类一新种：前鳃亚纲：中腹足目

作者从吉林省盘石县红南林场采得环口螺科一新种:盘石双边凹螺 Chamalycaeus panshiensis,本文对该新种的形态特征作了详细描述,尤其对齿舌作了显微观察,其齿式为(2:1:1:1:2)/57。作者并与近似种拉氏双边凹螺 Chamalycaeus rathouisianus(Heude,1882)进行了比较。     

四种翁戎螺的齿舌形态及功能

翁戎螺（Pleurotomariidae）起源于寒武纪时期,是介于软体动物祖先和现代腹足类之间的过渡类型。目前我国翁戎螺的分类、生态等方面研究不足,为探究翁戎螺的形态分类及食性,以寺町翁戎螺（Bayerotrochus teramachii）、红翁戎螺（Mikadotrochus hirasei）、高腰翁戎螺（M. salmianus）和龙宫翁戎螺（Entemnotrochus rumphii）为研究对象,应用扫描电镜观察其齿舌结构。结果表明,（1）翁戎螺齿舌结构与大多数腹足类具有3种类型的齿舌不同,其齿舌带上具有中央齿、内侧齿、外侧齿、镰状齿、丝状齿和桨状齿6种不同类型的小齿。（2）4种翁戎螺的中央齿均为1枚,内侧齿2或3枚,外侧齿20 ~ 25枚,镰状齿16 ~ 32枚,丝状齿35 ~ 62枚,桨状齿10 ~ 26枚。（3）翁戎螺属（Mikadotrochus）内种类之间齿舌形态的差异较小,进行种间区分需结合其小齿数量,但属间差异较大,中央齿、内侧齿、镰状齿的齿尖和齿基形态都可以进行属间区分。（4）龙宫翁戎螺齿舌带每个横排具有26枚桨状齿,与之前研究具有10枚不同。本研究对翁戎螺镰状齿和丝状齿之间、丝状齿和桨状齿之间的过渡形态进行深入地描述和划分。本研究结果可为我国翁戎螺的形态分类研究提供资料。     

Sutarostrongylus Johnsoni sp. n. (Nematoda: Trichostrongylina, Heligmosomoidea) from the pademelon, Thylogale stigmatica (Marsupialia) from Queensland, Australia

A new species of heligmosomoid nematode Sutarostrongylus johnsoni sp. n., belonging to the sub-family Herpetostrongylinae Skrjabin & Schultz, is described from the small intestine (duodenum) of the red-legged pademelon, Thylogale stigmatica (Gould, 1860) (Marsupialia: Macropodidae), from north-eastern Queensland, Australia. The only other species of the genus S. kirkpatricki Beveridge & Durelte-Desset, 1986 occurs in the related host, the red-necked pademelon, T. thetis (Lesson, 1827) in south-eastern Queensland. The new species differs in having longer spicules and asymmetrical spicule tips as well as the presence of a comarete which develops on the right ventral aspect of the mid-region of the body. The synlophe of the new species is unusual in that the inclination of the axis of orientation changes from being oblique in the anterior part of the body to being frontal in the posterior part. The same change may occur in some species of Austrostrongylus Chandler, 1924. Current data suggest that species of Sutarostrongylus are limited to a single genus of host, Thylogale Gray, 1837 and support the suggestion that both nematode species exhibit morphological features which are intermediate between those occurring in Herpetotostrongylinae in dasyurid marsupials and those occurring in macropodid marsupials.     

Revision of the Progamotaenia zschokkei (Janicki, 1905) complex (Cestoda: Anoplocephalidae), with the description of six new species

A review of cestodes currently attributed to Progamotaenia zschokkei (Janicki, 1905) (Cestoda: Anoplocephalidae) suggests that six additional species are present: Pr. tenuis n. sp. found in Thylogale stigmatica (Gould) and T. thetis (Lesson), Pr. lomatosoma n. sp.from Macropus agilis (Gould), Pr. petrogale n. sp. from Petrogale spp. and Macropus dorsalis(Grey), Pr. fimbriata n.s p. from Lagorchestes conspicillatus Gould and L. hirsutus Gould, Pr. obesa n. sp. from Onychogalea fraenata (Gould) and O. unguifera (Gould) in north-eastern Australia and Pr. kellerae n. sp. from O. unguifera in north-western Australia. The new species are differentiated by a combination of characters: prominence of scolex lobes, number of lobes in the fimbriated velum, testis number and distribution, size of the cirrus-sac, morphology of the uterus and presence or absence of a pyriform apparatus in eggs from terminal segments. The morphological differences found support earlier molecular studies, in that cestodes within each host genus are distinct, with the exception that considerable morphological variation exists within Pr. petrogale. Principal components analysis suggested that most of the cestodes from Petrogale spp. belonged to Pr. petrogale. The status of specimens from Pe. lateralis is unclear. More detailed molecular studies are required to determine the significance of the morphological variation within this taxon. A key is provided to species within the complex and the related species Pr. villosa (Lewis, 1914).     

On two nematodes from Brazilian birds and description of a new species (Acuarioidea, Schistorophinae) parasitizing Laterallus viridis (Müller, 1776) (Gruiformes, Rallidae)

The present paper reports acuarioid nematodes recovered from avian hosts. A new species of the genus Schistorophus Railliet, 1916 is proposed based mainly on findings referring to ptilina, spicules and vagina. Ancyracanthopsis coronata (Molin, 1860) Chabaud & Petter, 1959 is referred again in Brazil since its proposition in 1860, from specimens recovered from a Brazilian bird. A revised key to the species of the genus Schistorophus is also presented.     

Geographic variation in the dichanthelium aciculare complex (Poaceae)

Geographic variation in theDicanthelium aciculare complex was studied by principal components analysis. Few of the attributes analyzed show high correlations with one another, but pubescence patterns are of value in the discrimination of taxa. Sharp differences between phenetic clusters are restricted to one or two geographical regions. When viewed as a whole the complex forms a mosaic of variation patterns and the boundaries between phenetic clusters fade. The complex is reduced to two species,Dichanthelium aciculare (Desv. ex Poir.) Gould & Clark andD. consanguineum (Kunth) Gould & Clark.     

Gould’s replay revisited

This paper develops a critical response to John Beatty’s recent (2006) engagement with Stephen Jay Gould’s claim that evolutionary history is contingent. Beatty identifies two senses of contingency in Gould’s work: an unpredictability sense and a causal dependence sense. He denies that Gould associates contingency with stochastic phenomena, such as drift. In reply to Beatty, this paper develops two main claims. The first is an interpretive claim: Gould really thinks of contingency has having to do with stochastic effects at the level of macroevolution, and in particular with unbiased species sorting. This notion of contingency as macro-level stochasticity incorporates both the causal dependence and the unpredictability senses of contingency. The second claim is more substantive: Recent attempts by other scientists to put Gould’s claim to the test fail to engage with the hypothesis that species sorting sometimes resembles a lottery. Gould’s claim that random sorting is a significant macroevolutionary phenomenon remains an intriguing and largely untested live hypothesis about evolution.     

Two new species of Brueelia Kéler, 1936 (Ischnocera, Philopteridae) parasitic on Neotropical trogons (Aves, Trogoniformes)

Two new species of Brueelia are described and illustrated. These new species and their type hosts are: Brueelia sueta ex Pharomachrus pavoninus (Spix, 1824), the Pavonine Quetzal and Brueelia cicchinoi ex Trogon viridis Linnaeus, the White-tailed Trogon. Both new species differ from the only Brueelia described on Trogon mexicanus by many morphological features, including those present in the male genitalia and female vulvar margin. Partial sequences of the mitochondrial cytochrome oxidase I (COI) gene for these two new species differ from one another by 13.6% uncorrected p-distance. Whereas Brueelia cicchinoi is only 0.3% divergent from previously published COI sequences identified as Brueelia sp. from the Mexican Trogon melanocephalus Gould, 1936 and Trogon massena Gould, 1938. We also found Brueelia cicchinoi on Trogon melanurus, Trogon collaris and Pharomachrus pavoninus. Thus Brueelia cicchinoi is found on multiple trogoniform hosts across an extremely large geographic distribution and has one of the largest number of host associations among Brueelia species.     

Molecular support for a rapid cladogenesis of the woodpecker clade Malarpicini, with further insights into the genus Picus (Piciformes: Picinae)

Previous studies have suggested that the woodpecker genus Picus (Aves: Picidae) may not be monophyletic. In order to evaluate this hypothesis, we analyzed DNA sequences from all but two species of Picus, as well as from representatives of all genera in the tribe Malarpicini, within which Picus is nested. We sequenced seven loci (four autosomal, one Z-linked and two mitochondrial) with different evolutionary dynamics. The species currently placed in Picus fall into two subclades that may not form a monophyletic assemblage. Consequently, we propose to place miniaceus Pennant 1769, flavinucha Gould 1834 and mentalis Temminck 1825 in the genus Chrysophlegma Gould, 1850, while the remaining species are retained in Picus. The inclusion in our study of representatives of all genera included in the tribe Malarpicini, a group of woodpeckers which has proven difficult to resolve in several previous molecular studies, also allowed us to determine the earliest divergences within this clade. The results suggest that the low level of basal resolution in Malarpicini is attributable to multiple cladogenetic events in a short period of time rather than insufficient character sampling. This conclusion is supported by the observation of nucleotide insertion-deletions that support mutually exclusive phylogenetic hypotheses in different gene trees. We attribute this pattern of incongruent indels, together with short internodes in the tree, to incomplete lineage sorting.     

Two new Aggregata species (Apicomplexa: Aggregatidae) infecting Octopus tehuelchus and Enteroctopus megalocyathus (Mollusca: Octopodidae) in Patagonia, Argentina

During a long-term study carried out between 1981 and 1996 on the biological and fishery aspects of octopuses inhabiting the Gulfs of San Matías, San José, and Nuevo, Patagonia, Argentina, 2 new species of Aggregata (Apicomplexa: Aggregatidae) were found in the digestive tracts of Octopus tehuelchus d'Orbigny, 1834 (prevalence 72%) and Enteroctopus megalocyathus (Gould, 1852) (prevalence 77%). Both species can be distinguished from other congeners on the basis of their hosts, the diameters of sporocysts, and number and length of sporozoites. Despite overlap in the distributions of the two hosts species in the area covered in this study, both Aggregata new species exhibited high host specificity.