Revision of the sesarmid crab genera Labuanium Serène and Soh, 1970, Scandarma Schubart,Liu and Cuesta, 2003 and Namlacium Serène and Soh, 1970 (Crustacea: Decapoda: Brachyura: Sesarmidae), with descriptions of four new genera and two new species

ABSTRACT

The systematics of the arboreal sesarmid crab genera Labuanium Serène and Soh, 1970 and Scandarma Schubart, Liu and Cuesta, 2003 is revised. Also included is the poorly known genus Namlacium Serène and Soh, 1970, which is morphologically similar to Labuanium and may also be arboreal in habit. The present study restricts Labuanium to its type species, L. politum (De Man, 1887), and congeners are transferred to Scandarma, Geosesarma De Man, 1892, and three new genera established herein: Circulium gen. nov., Shinobium gen. nov. and Mindanium gen. nov. Two new species of Scandarma are described from Papua New Guinea and Madagascar. Sesarma jacquinoti Ortmann, 1894, previously regarded as a synonym of Scandarma gracilipes (H. Milne Edwards, 1853) (comb. nov.), is here shown to be a junior synonym of Sesarmops angustifrons (A. Milne-Edwards, 1869). Labuanium schuetteii (Hess, 1865) is regarded as conspecific with Scandarma gracilipes (H. Milne Edwards, 1853) (comb. nov.) and the lectotype of the latter species (here designated) is also selected as the neotype of the former, making the two names objective synonyms. Material which had been identified as ‘Labuanium finni Alcock, 1900’ by Pretzmann (1984) from the South Andaman Islands is actually the poorly known Geosesarma thelxinoe (De Man, 1908), which is here referred to a new genus, Andamanium gen. nov. Sesarma finni Alcock, 1900 s.s. is herein assigned to Scandarma. Namlacium crepidatum (Calman, 1925), the only species in the genus, is redescribed and figured and compared with Labuanium and Scandarma. Keys to species of Circulium and Scandarma are provided.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:414B8DAA-584F-4070-A355-83B583D0D017     

有效微生物(EM)在中华绒螯蟹养殖中的应用

为探讨有效微生物( EM)对蟹塘水质和螃蟹成活率的改善作用,在南京市高淳区螃蟹文化园开展了EM应用试验研究。试验结果表明：在中华绒螯蟹养殖过程中投加EM,能有效降低水体中污染物的质量浓度,提高螃蟹成活率,但EM投加质量浓度不宜过大。当籽( EM)=1.5 mg/L时,蟹塘水体中NH+4-N、NO-2-N、COD和TP的质量浓度比不投加EM的对照塘降低12.7%~29.2%,螃蟹成活率提高2.4%;籽( EM)=6.0 mg/L时,NH+4-N、COD和TP的质量浓度分别降低1.1%、14.4%、0.03%,而NO-2-N 升高15.6%,螃蟹成活率升高1.0%。由此可见,当 EM 投加质量浓度过高(6.0 mg/L)时,水质指标及成活率改善效果不如EM投加质量浓度较低时(1.5 mg/L),且会引起NO-2-N的累积。     

Population structure and breeding season of the hermit crab Diogenes brevirostris Stimpson, 1858 (Decapoda,Anomura, Diogenidae) from southern Mozambique

In this study the population dynamics of the diogenid hermit crab Diogenes brevirostris is evaluated focusing on size structure, sex ratio and breeding season. Crabs were randomly taken on a monthly basis from January to December 2003 at Costa do Sol, Maputo Bay, southern Mozambique. A total of 622 crabs was obtained of which 290 were males (46.6%), 170 were non‐ovigerous females (27.3%) and 162 were ovigerous females (26.1%). The overall size frequency distribution was unimodal for males, non‐ovigerous females and ovigerous females. The overall sex ratio (1:1.15) differed from the expected 1:1 ratio. Sexual dimorphism was evidenced by the larger size attained by males in relation to both ovigerous and non‐ovigerous females. Breeding took place year‐round with three peaks of spawning (March, August and December). Despite the high reproductive activity, young recruits were scarce in the population. The present results suggest that the study area is suitable for reproduction and growth whereas recruitment may take place in different areas from that occupied by the adults.     

Breeding season of the hermit crab Dardanus deformis H. Milne Edwards, 1836 (Anomura,Diogenidae) in Maputo Bay,southern Mozambique

The breeding season of the hermit crab Dardanus deformis is studied based on the occurrence of ovigerous females, in relation to temperature and rainfall. Monthly samples were obtained between January and December 2003 at Costa do Sol, Maputo Bay, southern Mozambique. A total of 331 female individuals was analysed of which 164 were non‐ovigerous females and 167 were ovigerous females. Dardanus deformis breeds continuously in the study area with peaks of spawning from August to October and a slight decrease from May to July. Both temperature and rainfall were positively correlated with percentages of ovigerous females. Multiple linear regressions suggest that rainfall is the main factor controlling the breeding activity of D. deformis in Maputo Bay. This species may have a rapid and high reproductive activity in the study area as observed by the higher number of ovigerous females relative to non‐ovigerous females which may contribute to a constant larval supply and recruitment of this species in the study area.     

Structure and distribution of carapace setae in British spider crabs

Carapace setae were examined by SEM in species of spider crabs (Family Majidae). These setae are predominantly hamate (i.e. hooked), to which extraneous materials are attached for the purpose of concealment. They are described for eight species collected around the Isle of Man. In each species setae were sorted to types on the basis of consistent differences in size, shape and fine structure. Diversity ranged from two to six types per species, and this was examined in the context of their masking, or camouflage, habits. Certain setae can be assigned to particular species, so a limited taxonomic usage is indicated: however, further work is required for this to become a comprehensive tool. Distribution of setal types on the carapace is also described, and compared to patterns reported in previous studies.     

Limb regeneration in a common South-American littoral crab Cyrtograpsus angulatus

The intermoult period (time elapsed between two successive moults) is shortened, its variation among individuals and the size increment at moult are reduced, in juveniles of the littoral crab Cyrtograpsus angulatus when the number of regenerating limbs increases. Bud growth rates of regenerating limbs are calculated from plots of R₄ (length of third or fourth limb bud. 100/carapace width) as a function of relative time, considering that the intermoult period corresponds to 100%. Bud growth rates remain similar for crabs with a different number of limbs autotomized soon after moult. Regeneration of a second set of autotomized limbs follows autotomy if it occurs before the growing buds of a first set have a relative size R₄ < 16. Buds of contralateral limbs autotomized at different times during the moult cycle have similar final R₄ values because their growth rates are higher for limbs lost later. Buds of limbs, autotomized after part of the moult cycle has elapsed since moult, also tend to grow faster than those lost earlier. Neither the intermoult period nor the size increment at moult are modified by a second autotomy, after or before the critical R₄ value, and by the autotomy of a single limb in different moments of the moult cycle.     

不确定关系的广义表达式

利用力学量算符的厄密性和内积三公理,给出了不确定关系的广义表达式及其严格数学证明,深入细致地讨论了广义不确定表达式所解释的内涵,阐明了一些经常被忽略的特征,纠正了一些文献不妥的解释.