中国真管螺属一新种记述(肺螺亚纲,柄眼目,烟管螺科)

记述采自贵州省陆生贝类1新种,即白脉真管螺Euphaedusa leucophlebia sp.nov.,对新种形态特征、栖息环境进行了描述,并对其相似种进行了分析和讨论.     

The fate of received sperm in the reproductive tract of a hermaphroditic snail and its implications for fertilisation

Multiple mating, sperm storage and internal fertilisation enhance sperm competition. The great pond snail can use stored sperm for over three months, and frequently mates with different partners. This hermaphrodite, Lymnaea stagnalis, can also self-fertilise and often produces egg masses containing both selfed and outcrossed eggs. Hence, a sperm recipient may exert considerable control over paternity. Using microsatellite markers, we show that when allosperm are present, all genotyped eggs are cross-fertilised. We also find that sperm have the opportunity to compete, because double matings lead on average to equal paternity for each sperm donor. This indicates that received sperm are randomly mixed in storage. To gain further insight into the mechanisms underlying the process of sperm storage, digestion and utilisation, we investigated the fate of donated sperm at different times after copulation. We find that within 3 h after transfer most sperm have been transported into the sperm-digesting organ. Fluorescent labelling of sperm in histological sections further reveals that allosperm are not stored in the fertilisation pouch, but upstream in either the hermaphroditic duct, seminal vesicles, or ovotestis. Besides contributing to the understanding of the mechanisms underlying sperm competition and/or cryptic sperm choice, this study shows that mixed mating cannot be treated as a separate issue in hermaphroditic animals.     

中国丽管螺属的研究(肺螺亚纲:柄眼目:烟管螺科:管螺亚科)

现已知我国烟管螺科丽管螺属共计１７种和亚种,主要分布于我国四川,云南,湖北,湖南,江西,浙江等处区,即分布于我国秦岭以南广东东洋界地区。作者在云南路南县石林地区采得丽管螺属一新种,即路南丽管螺,作者对我国已知的丽管螺属的种类进行了整理分析,对新种进行了描述。     

中国虹蛹螺科二新种(肺螺亚纲:柄眼目:虹蛹螺科)

作者 作者晨贵州省镇宁布依赖苏州自治县境内采得陆生贝类标本一批,经鉴定得喇叭螺属２种,即：天星桥喇叭螺,新种Ｂｏｙｓｉｄｉａ （Ｂａｎｓｏｎｅｌｌａ）ｔｉａｎｘｉｎｇｑｉａｏｅｎｓｉｓ,Ｌｕｏ,Ｃｈｅｎ ｅｔ Ｚｈａｎｇ ｓｐ．ｎｏｖ 果喇叭螺,新种Ｂｏｙｓｉｄｉａ（Ｂｏｙｓｉｄｉａ）ｈｕａｎｇｇｕｏｓｈｕｅｎｓｉｓ Ｌｕｏ,Ｃｈｅｎ ｅｔ Ｚｈａｎｇｅ,ｓｐ．ｎｏｖ。对新种的形态进行了详细描述     

A peculiar new species in the genus Landouria Godwin-Austen, 1918 from China (Gastropoda: Heterobranchia: Stylommatophora: Camaenidae)

Landouria omphalostoma n. sp. is described from northern Yunnan, China. The new species is placed in the genus Landouria Godwin-Austen, 1918 based on the presence of tuberculated flagellum and swollen basal part in the bursa copulatrix, and on the absence of dart sacs and mucous glands. L. omphalostoma n. sp. is characterized by a horizontal aperture of the shell which is unique in the genus. This feature resembles those of only two other camaenid/bradybaenid taxa, species of the Chinese genus Pseudaspasita Möllendorff, 1902 and species of the Japanese genus Coelorus Pilsbry, 1900. This is the first verified record of the genus in China and the easternmost record of Landouria. This paper provides the taxonomic ground work for further studies of the repeated evolution of a horizontal aperture.     

中国光螺属一新种记述(肺螺亚纲,柄眼目,拟阿勇蛞蝓科)

在整理陕西师范大学生命科学学院许升全先生赠送的陆生贝类标本时,经鉴定发现1新种,即太白山光螺Xesta taibaishanensis sp.nov..隶属腹足纲、肺螺亚纲、柄眼目、拟阿勇蛞蝓科、光螺属.对新种形态特征、栖息环境进行了记述,并与近似种进行了比较和讨论.     

Cold tolerance and freeze-induced glucose accumulation in three terrestrial slugs

Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures in their habitat. Slugs spontaneously froze at about − 4 °C when cooled under dry conditions, but freezing of body fluids was readily induced at − 1 °C when in contact with external ice crystals. All three species survived freezing for 2 days at − 1 °C, and some A. rufus and A. lusitanicus also survived freezing at − 2 °C. ¹H NMR spectroscopy revealed that freezing of body fluids resulted in accumulation of lactate, succinate and glucose. Accumulation of lactate and succinate indicates that ATP production occurred via fermentative pathways, which is likely a result of oxygen depletion in frozen tissues. Glucose increased from about 6 to 22 μg/mg dry tissue upon freezing in A. rufus, but less so in A. ater and A. lusitanicus. Glucose may thus act as a cryoprotectant in these slugs, although the concentrations are not as high as reported for other freeze tolerant invertebrates.     

Effect of a toxicant on phagocytosis pathways in the freshwater snail Lymnaea stagnalis

The disturbance of plasma membrane carbohydrates and of lipopolysaccharide (LPS) ligands in relation to cytoskeletal transformations of haemocytes has been investigated after chronic exposure of pond snails (Lymnaea stagnalis) to the peroxidizing toxicant fomesafen. Neither of the two lectins used (concanavalin A and wheat germ agglutinin) showed any binding modification after incubation of the snails in the presence of the toxicant. However, after exposure of the snails to fomesafen, a clear and persistent reduction in LPS labelling of haemocytes occurred. The actin cytoskeleton of the same cells also appeared to be sensitive to the toxicant. The reduction in LPS-binding sites was related to actin staining, leading to the hypothesis that LPS ligands and actin could be similarly modulated by the toxicant. Damaged cells showed non-adherent membrane portions with reduced filopodial extrusions, exhibiting a smooth surface free of microvilli. These changes could lower the spreading and adhesion of the cells and could therefore account for the loss in their phagocytic capabilities.     

The comparative anatomy and systematics of Jamaican Urocoptidae (Mollusca: Pulmonata)

Jamaican Urocoptidae can be assigned to three subfamilies, the Urocoptinae Pilsbry 1902, Apominae Paul 1982 and Microceraminae Pilsbry 1902, on shell and anatomical characters. Urocoptinae are characterized by a cylindrical or conical decollate shell; genitalia with an elongate spermatheca and no penial retractor muscle; the left ocular retractor arising from the pharyngeal retractor and both oculars divided anteriorly; a short or long radula (L/W ≏ 5 or ≏ 10) with V-shaped rows of teeth, no marginals and the mesocones and ectocones of laterals widely separated in alternating rows; and include the genera Urocoptis Beck, Anoma Albers and Spirostemma Pilsbry & Vanatta. The Apominae are characterized by elongate-cylindrical decollate shells; genitalia with a globular spermatheca and a penial retractor muscle; both ocular retractors arising from the pharyngeal and both divided anteriorly; an extremely long radula (L/W= 25–45) with narrow, weakly-lobed centrals flanked by two enormous laterals with ectocones reduced or absent, and 4–9 marginals; and include the genera Apoma Beck, Mychostoma Albers, Geoscala Pilsbry & Vanatta and Simplicervix Pilsbry. The type species of the type genera of both subfamilies occur in Jamaica and their anatomy is described. Jamaican Microceraminae include one species, Microceramus gossei (Pfeiffer) which has a conical, entire shell; genitalia with an oval spermatheca and no penial retractor muscle; neither ocular retractor arising from the pharyngeal and neither branched anteriorly; a short radula (L/W ≏ 5) with straight rows of lateral teeth and no marginals. Cladistic analysis suggests that Microceramus is the most primitive genus; that within the Urocoptinae Anoma and Spirostemma are more closely related to each other than either is to Urocoptis ; and that within the Apominae, Apoma is less closely related to Mychostoma, Geoscala and Simplicervix than they are to each other.