Adaptations of the chiton Sypharochiton pelliserpentis to rocky and estuarine habitats

Various morphological and physiological features of Sypharochiton pelliserpentis (Quoy & Gaimard, 1835) were examined in relation to the different physico‐chemical characteristics experienced at 4 sites on Kaikoura Peninsula and 2 sites in the Avon‐Heathcote Estuary. Body water content of chitons from high‐shore exposed and estuarine rocky sites was significantly greater (P<0.005) and desiccation rates were significantly less (P<0.05) than those of chitons from low‐shore marine sites and an estuarine mudflat. The percentage of body water loss causing death was greatest for high‐shore marine chitons and least for estuarine chitons. Estuarine chitons had relatively more gill tissue than marine individuals. Body shape appeared to be correlated with intensity of wave action, and narrow animals were found in more wave‐exposed areas. Variations in radula length showed no clear‐cut trends among localities.     

A new species of Plaxiphora (Mollusca: Polyplacophora) from southern New Zealand

Plaxiphora boydeni n.sp. from wave‐exposed rocky shores of southern New Zealand is described and illustrated. This is the first published record of the genus from the New Zealand mainland. P. boydeni is readily distinguished from the 2 other New Zealand species of the genus, which occur in the subantarctic region, by the absence of bristle‐tufts on the girdle.     

9种石鳖壳板的形态研究

对我国沿海的朝鲜鳞带石鳖Lepidozona coreanica,花斑锉石鳖Ischnochiton comptus,函馆锉石鳖Ischnochition hakodadensis,红条毛肤石鳖Acanthochiton rubrolineatus,异毛肤石鳖Acanthochiton dissimilis,平濑锦石鳖Onithochitonhirasei,日本花棘石鳖Liolophura japonica,网纹鬃毛石鳖Mopalia retifera,史氏宽板石鳖Placiphorella stimpsoni等9种石鳖贝壳的结构进行了观察。研究发现:9种石鳖中,除史氏宽板石鳖外,其它种的贝壳总长占体长比例都在80%以上;除2种毛肤石鳖外,壳板宽与体宽之比都达60%以上。红条毛肤石鳖壳板最窄,其壳板宽度只占体宽的45%;石鳖的头板、中间板和尾板中,嵌入片上的齿裂数具有种间差异,以头板区别最大;除朝鲜鳞带石鳖、花斑锉石鳖和函馆锉石鳖较多之外,其它6种石鳖的尾板嵌入片上齿裂数均少于3个;除函馆锉石鳖外,其它8种石鳖的中间板嵌入片上的齿裂均不超过2个;史氏宽板石鳖的中间板和尾板嵌入片上没有齿裂。另外,壳表面上的各种壳饰,壳板上的嵌入片、缝合片等结构特征也具有种间差异。     

蜑螺科软体动物系统分类学研究进展

蜑螺科是一类广盐性腹足类动物,主要分布在热带和亚热带海域,是潮间带底栖生物群落的重要组成部分之一,该科动物为探讨物种适应辐射及热带海域生物多样性模式提供了重要研究材料。本文对蜑螺科的国内外系统分类学研究现状和趋势进行了回顾与展望。蜑螺类动物为适应不同生境而进化出多样的贝壳形态,仅依据外部形态很容易产生误导或错误鉴定,因此蜑螺科的分类系统以及一些种属的有效性仍存在争议。我国缺乏系统的蜑螺科分类学研究,已报道的种类还不能完全反应中国海实际的物种数。未来需强化标本采集,在传统形态学分类的基础上,借助分子生物学和解剖学等手段,明确中国海蜑螺科种属组成和区系特点,进而完善蜑螺科的系统分类学研究。     

Ecology of New Zealand abalones,Haliotis species (Mollusca: Gastropoda)

The spawning season of Haliotis iris Martyn, as indicated by a gonad index and examination of ovaries, was late summer to autumn at Kaikoura, New Zealand, in 1967–68. In contrast, H. australis Gmelin spawned twice, once in the spring and again in the late summer to autumn. Both patterns are typical of haliotids. But in the 1968–69 year neither species spawned; full gonads with apparently ripe eggs were maintained through the winter of 1969. No reason for this inconsistency can be offered. Haliotis iris at Taylors Mistake, 154 km south, followed essentially the same pattern as Kaikoura H. iris through 1968, but spawned slightly in autumn 1969.

Haliotis iris first produces mature eggs when it is about 60 mm long and probably spawns substantially for the first time when it is 4 years old. Although fecundities of larger animals reached about 11 million eggs, not all of these were necessarily spawned. Haliotis australis also first produces mature eggs when it is about 60 mm long, but the age at which first spawning takes place could not be determined; maximum fecundity is about 3 million eggs. The sex ratios did not differ significantly from 1: 1 for either species.     

Ecology of New Zealand abalones,Haliotis species (Mollusca: Gastropoda)

Growth rates of three species of abalone in New Zealand were estimated by fitting data to the von Bertalanffy growth equation. Length‐frequency analysis and tagging were used for Haliotis iris Martyn, and shell growth‐checks were used for H. australis Gmelin and H. virginea Gmelin. The relative growth coefficient (K) and the asymptotic length (L8) were found to be 0.3104 and 146.2 mm respectively for H. iris, 0.3205 and 86.75 mm for H. australis, 0.4460 and 61.5 mm, and 0.3231 and 64.4 mm for H. virginea from two separate localities. An absolute growth curve could be calculated only for Haliotis iris.     

Ecology of New Zealand abalones,Hahotis species (Mollusca: Gastropoda)

Tagging of Haliotis iris Martyn at colonies near low water, and subsequent regular observations over 18 months, showed that significant movement tended to occur only in autumn and winter when rough seas disturbed the habitat. These movements may vary from year to year depending on sea conditions. Tn contrast, subtidal colonies dispersed more gradually, seemingly disturbed by the tagging operation and subsequent rehandling. Other colonies which were not tagged remained apparently unchanged for up to 2 years. Individuals in subtidal H. australis Gmelin colonies also did not move to any great extent over this period: this species inhabits narrow crevices and appears to be a much more active animal than H. iris, both in the field and in the laboratory. Drift and attached algae were virtually absent from the crevices inhabited by H. australis and it seems likely that the species must forage to feed. A homing mechanism may be present because many older H. australis are found in deep scars on the rocks or have characteristically worn shell edges fitting the rock of their particular site.

A 24‐hour watch on a tagged, subtidal colony of Haliotis iris at Kaikoura showed that there was very little movement diurnally, and it seems likely that feeding is passive; drift algae are available at most times. No evidence of homing behaviour was detected.     

Aspects of larval,post-larval and juvenile ecology of Macrobrachium petersi (Hilgendorf) in the Keiskamma estuary,South Africa

Although Macrobrachium petersi has nine larval stages, only stage I and a minimal number of stage II M. petersi larvae were caught in the Keiskamma estuary. Stage I larvae undergo a vertical migration at night which is markedly influenced by salinity, especially under stratified conditions. Larvae remain in the water column on the ebb tide, a behavioural pattern which effectively carried them to favourable salinities for growth and development. Stage I larvae show an association with salt front regions. The sudden decline in larval abundance from stage I to stage II downstream from the front suggests a change from a pelagic to an epibenthic existence. Later larval stages failed to appear in the plankton. However, post-larvae were caught in the estuary and a juvenile migration from the estuary to freshwater was monitored.     

栉江珧生殖细胞的发生

通过观察栉江珧 (Atrina pectinata linnaeus)的未分化生殖细胞 ,精原细胞和卵原细胞 ,精母细胞和卵母细胞 ,精子和卵子的形态结构与分布状况及核仁在卵成熟过程中的变化 ,对栉江珧生殖细胞发生及成熟过程的有关问题进行了探讨。     

Notes on New Zealand chitons (Mollusca,Amphineura)

A synopsis of the classification of the New Zealand Polyplacophora is presented. The name Lepidochitonidae is replaced by the earlier Callochitonidae, Plaxi‐phoridae by Mopaliidae, Aulacochitonidae by Schizochitonidae, and Cryptocon‐chidae by Acanthochitonidae.

Vaferichiton Iredale and Hull is treated as a subgenus of Aerilamma Hull. Lorica H. and A. Adams is used instead of its junior synonym Aulacochiton Shuttleworth. Lorica haurakiensis Mestayer is recorded from the Nukumaruan (Lower Pleistocene). Paricoplax profundior Dell is placed in Loricella Pilsbry. Icoplax chathamensis Dell is made the type species of a new subgenus of Anthochiton Localities in southern New Zealand for Notoplax cuneata (Suter) and Lorica haurakiensis are listed.     

满月蛤目(双壳纲:异齿亚纲)软体动物分类与系统演化研究进展

满月蛤目物种是海洋常见的双壳类软体动物,通常生活在有机质含量较高或化能生态系统中,是这两类生态环境中的主要类群。本文回顾了满月蛤目分类与系统演化的研究历史。随着受关注程度的增加以及技术手段的发展,世界范围内出现大量的分类和系统演化研究,但由于物种繁多、样品获取困难、贝壳形态多变,该类群的分类系统仍存在大量尚未解决的问题,且其物种多样性被严重低估。我国对该类群系统性的研究尚未开展。未来需加强标本采集,结合新技术进行整合分类学研究以摸清我国满月蛤目物种组成和区系特点,完善分类系统,进而对其起源演化、扩布路径等问题进行探究。     

Ecology of Pinnidae (Mollusca: Bivalvia) from the Gulf of Thailand

The ecology of the family Pinnidae was studied by sampling three pinnid species from 36 sampling sites across four different microhabitats in the Gulf of Thailand. The species spatial distributions were mostly uniform, with some populations having random distributions. Species abundances differed between sandy and coral habitats according to non-metric multi-dimension scaling analyses. Although the Gulf of Thailand is a relatively small geographic area, habitats are varied enough to provide variable shell densities. Small islands are important distribution areas, and coral reefs provide both direct and indirect shelter which support high abundances, densities and increased shell size. The highest density was recorded in sand beds within coral reefs. Low density and small shell size in sand beaches might be related to high mortality in shallow water or to adaptations for survival in shallow waters. A clear correlation between sediment composition and species abundance was found in Pinna atropurpurea; abundance increased with the sand content of the sediment. For P. deltodes, abundance increased as the rock fraction of the sediment increased. These results suggest that adaptations in Pinnidae, such as shell size, shell morphology, and the exposure of the shell above the sediment-water interface, are responses for survival in different habitats.     

蟹守螺总科软体动物的系统分类学研究进展

蟹守螺总科(Cerithioidea)是一群古老、极度多样化的腹足类,广泛分布于全球热带至温带的水域中,是腹足类生态和进化研究中重要的关键群体.目前蟹守螺总科动物整体上属于了解较少的类群,其定义也一直在修订中.随着贝类学研究理念的进步与技术手段的发展,蟹守螺总科的分类学与系统发育学研究等有了较大进展,但仍然有许多问题亟...     

鳞侧石鳖属(Leptochiton)一物种在西太平洋雅普海沟分布的新记录

蛟龙号载人潜水器在位于雅普海沟北部6 745 m深处的底栖沉积环境中采集到两只石鳖样本,这是石鳖物种分布于此的新记录。形态学和DNA分子标记均支持两只石鳖为鳞侧石鳖属（Leptochiton）同一物种。该种在形态上与L.vanbellei和L.deforgesi接近;在系统发生方面,与L.vanbellei,L.deforgesi和L.boucheti的亲缘关系密切。这是截至目前世界石鳖分布报道的第三深度记录。     

Population variations in the grazing turbinid Lunella smaragda (Mollusca: Gastropoda)

The grazing turbinid gastropod Lunella smaragda was sampled regularly over 3.5 y from precise sites of different microtopography and height on the platform shore at Goat Island Beach near Leigh, Northland, New Zealand. Growth is linear for over 3 y, and the year‐classes distinct. The position of the different size‐classes is related to both the shelter afforded by the microtopography, and to the height on the shore. The populations in the mid‐eulittoral turf flats, low eulittoral bare rock areas, and the sublittoral fringe are distinct, and there is a general movement down the shore with age and size. Wave action apparently dislodges the animals from higher areas when they grow to a critical size and transports them to sites lower on the shore, where wave disturbance is less. Field experiments with marked animals and laboratory studies with a wave tank confirm that the wave‐effected distribution is size related. However measurements showed that the ratio of foot attachment area to the shell area presented to the wave does not vary with animal size. The possible benefits of wave dislodgment and wave‐effected distribution are considered.     

Feeding Habits of Ocinebrina edwardsi (Mollusca: Prosobranchia) a Common Mussel Drill of the Italian Coasts

Abstract. The shell-boring gastropod Ocinebrina edwardsi (PAYR.) lives associated with Mytilus galloprovincialis LMK on which it preys. Predation is preferentially directed towards small (< 15 mm long) mussels. The predation rate (number of mussels eaten per gastropod per day) for medium sized mussels (16–25 mm long) during a year ranges from 0.03 to 0.11. The predation rate is directly influenced by the sea-water temperature. Predation follows a seasonal cycle reaching a maximum in July and a minimum in January. O. edwardsi drills selectively the median anterior region of the mussel valve, close to the dorsal edge.     

Two new species of Naticidae (Mollusca, Gastropoda) from the coast of China

Two new species of Naticidae （ Mollusca, Gastropoda） collected from the coast of China are described： Cryptonaitca huanghaien- s/s sp. nov. and Sinum vittatum sp. nov. The morphological characteristics between the new species were described and the related information was provided. The similarities and differences between the new species and related species were also compared and discussed. The new species Cryptonaitca huanghaiensis differed from Cryptonaitca hirasei and Cryptonaitca andoi in outer shape, operculum and radula. The new species Sinum vittatum is similar to Sinumjaponicum （Lischke, 1869）, but the shell of the former is flat-elliptical in shape, spire very small, slightly convex. While the latter is flat-globular in shape, apex light brown in color, without a brown band on the body whorl. The comparison results revealed that Cryptonaitca huanghaiensis and Sinum vittatum were two new species from the coast of China. Specimens studied were obtained from collections in the Marine Biological Museum, Chinese Academy of Sciences.     

南海蜑螺科一新记录属和一新记录种记述 (软体动物门:腹足纲:珍珠蜑螺目)

作者在整理中国科学院海洋生物标本馆馆藏蜑螺科Neritidae标本时,鉴定出产自海南三亚的一新记录属饰纹蜑螺属Vittina Baker,1924和一新记录种：裂蜑螺Vittina pennata（von Born,1778）。文中详细描述了本种的贝壳形态特征,查明了其生活习性和地理分布特点,并与相似种进行了比较和总结。