中国海鼓虾科角鼓虾属分类研究(甲壳亚门,十足目)

对中国海鼓虾科角鼓虾属系统分类进行了研究.角鼓虾全世界共记录34种,其中中国海记录了9种.本文中记录中国海分布的角鼓虾属Athanas 8种,其中对中国海2新纪录种A.polymorphus Kemp和A.squillophilus Hayashi,进行了描记,并提供了中国角鼓虾种检索表.在中国的材料中:A.japonicus、A.ohsimai、A.polymorphus及A.squillophilus 4种的螯足表现了多态性,A.ohsimai和A.squillophilus的螯足多态性也是首次发现和记载.所有研究测量标本均保存在中国科学院海洋研究所.     

Parallel Saltational Evolution of Ultrafast Movements in Snapping Shrimp Claws

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Description of Alpheus cedrici sp. n., a strikingly coloured snapping shrimp (Crustacea, Decapoda, Alpheidae) from Ascension Island, central Atlantic Ocean

Alpheus cedricisp. n. is described based on two specimens collected under rocks while scuba diving off the coast of Ascension Island, central Atlantic Ocean. The new species belongs to the Alpheus macrocheles (Hailstone, 1835) species complex and appears to be most closely related to the eastern-central Atlantic Alpheus macrocheles, the western Atlantic Alpheus amblyonyx Chace, 1972, and the eastern Pacific Alpheus bellimanus Lockington, 1877 and Alpheus rectus Kim & Abele, 1988. However, it differs from all these species by a combination of morphological characters and by a diagnostic and striking colour pattern.     

中国海鼓虾科阿莱鼓虾属分类研究(甲壳亚门,十足目)

阿莱鼓虾属 Arete Stimpson曾被多个研究者作为Athanas Leach角鼓虾属的异名处理(Banner and Banner,1960,1973;Chace,1988;Miya and Miyake,1968),作者认为Kemp(1915)描述Athanus polymorphus多形角鼓虾出现的第2胸足腕节4节为形态变异,第2胸足腕节分节情况完全可以将两属分开,阿莱鼓虾属应该做有效属处理.文中记述了中国海分布的3个种.borradailei,A.dorsdis,A.indicus,其中A.Borradailei为中国海首次报道.文中详细描述A.borradailei,并提供了世界阿莱鼓虾属种的检索表.所有研究标本保存在中国科学院海洋研究所.     

Morphological phylogeny of alpheid shrimps: parallel preadaptation and the origin of a key morphological innovation, the snapping claw

The Alpheidae-possibly the most diverse family of recent decapod crustaceans-offers attractive opportunities to study the evolution of many intriguing phenomena, including key morphological innovations like spectacular snapping claws, highly specialized body forms, facultative and obligate symbioses with many animal groups, and sophisticated behaviors like eusociality. However, studies of these remarkable adaptations remain hampered by insufficient phylogenetic information. We present the first phylogenetic hypothesis of relationships among 36 extant genera of alpheid shrimps, based on a cladistic analysis of 122 morphological characters from 56 species, and we use this hypothesis to explore evolutionary trends in morphology and species diversity. Our results strongly supported a monophyletic Alpheidae that included two hitherto difficult-to-place genera (Yagerocaris and Pterocaris). Of 35+ nodes among genera, all were supported by at least one morphological character (24 were supported by two or more) and 17 received greater than 50% jackknife support. Unfortunately, many basal nodes were only weakly supported. Six genera appeared nonmonophyletic, including the dominant genus Alpheus (paraphyletic due to inclusion of one clade with three minor genera). Evolutionary trends in alpheid claw form shed some revealing light on how key innovations evolve. First, several functionally significant features of the cheliped (claw bearing leg) evolved independently multiple times, including: asymmetry, folding, inverted orientation, sexual dimorphism, adhesive plaques that enhance claw cocking, and tooth-cavity systems on opposing claw fingers, a preadaptation for snapping. Many conspicuous features of alpheid claw form therefore appear prone to parallel evolution. Second, although tooth-cavity systems evolved multiple times, a functional snapping claw, which likely facilitated an explosive radiation of over 550 species, evolved only once (in Synalpheus + [Alpheus + satellite genera]). Third, adhesive plaques (claw cocking aids) also evolved multiple times, and within snapping alpheids are associated with the most diverse clade (Alpheus + derivative genera). This pattern of parallel preadaptation-multiple independent evolutionary origins of precursors (preadaptations) to what ultimately became a key innovation (adaptation)-suggests alpheid shrimp claws are predisposed to develop features like tooth-cavity and adhesive plaque systems for functional or developmental reasons. Such functional/developmental predisposition may facilitate the origin of key innovations. Finally, moderate orbital hoods-anterior projections of the carapace partly or completely covering the eyes-occur in many higher Alpheidae and likely evolved before snapping claws. They are unique among decapod crustaceans, and their elaboration in snapping alpheids suggests they may protect the eyes from the stress of explosive snaps. Thus one key innovation (orbital hoods) may have facilitated evolution of a second (snapping claws).     

Phylogeography of marine mutualists: parallel patterns of genetic structure between obligate goby and shrimp partners

The survival of many organisms depends on interspecific, mutualistic interactions. Hence, it is important to assess the phylogeography of multiple mutualistic species simultaneously to gain insight into how their metapopulations persist, spread and recover from disturbance. Consequently, we sequenced mitochondrial DNA (cytochrome b) from a gobiid fish (Ctenogobiops feroculus) and its mutualistic partner, an alpheid snapping shrimp (Alpheus djeddensis). These obligate mutualists are common in shallow coral reef lagoons, and we collected individuals from 11 Indo-Pacific islands that were likely exposed to different disturbance histories due to sea level fluctuations associated with glaciation events [geological studies indicate that eastern oceanic islands (Cook Islands, French Polynesia) were more disturbed than western continental plate islands that have deeper, more extensive lagoons (Okinawa, Fiji)]. Both phylogenetic and population genetic analyses indicated that gobies from Okinawa and Fiji were genetically distinct both from each other and those in the Cook Islands and French Polynesia. Shrimp, by contrast, grouped into two distinct genetic groups that showed no geographic structure. Restricting the analysis to one clade of shrimp, which contained two-thirds of the individuals, showed that these shrimp had very similar phylogeographical structure to the gobies. Mismatch distributions demonstrated that both gobies and shrimp experienced a recent, rapid population expansion into French Polynesia. Finally, nucleotide and haplotype diversities per sample location were significantly correlated between mutualists and tended to be higher on western continental than eastern oceanic islands. Our results suggest that these mutualists recovered from a major disturbance by colonizing South Pacific islands in synchrony.     

Size at sexual maturity,egg number and reproductive output of the snapping shrimp Alpheus euphrosyne euphrosyne De Man, 1897

Abstract

Aspects of the reproductive biology of snapping shrimp Alpheus euphrosyne euphrosyne inhabiting a tropical estuary were studied between August 2007 and July 2008 by examining 1309 females of 8.5–21.5 mm carapace length. Although the occurrence of ovigerous females was noted from October, the main breeding season extended from January to March. Size at 50% sexual maturity was estimated as 10.6±1.40 mm CL. Number of eggs per brood ranged from 141 to 1553 in females of 11.2 to 19.2 mm CL and mean absolute fecundity was estimated as 480±272 eggs. Regressions of log egg number on log total length, log carapace length and log weight revealed isometric relationships (p <0.01). Results of ANOVA revealed significant variation between mean short and long axes of eggs among five embryo developmental stages (P <0.05). The estimated egg batch 33 volume ranged from 4.99 to 32.09 mm³ with a mean of 12.44 mm³. Estimates of reproductive output from 41 females ranged between 8.21 to 31.25% with a mean value of 18.55±5.81.