日本沼虾精子在真虾部Caridea生殖进化中地位的研究

用透射电镜技术研究了日本沼虾成熟精子的形态结构，并和真虾部其它动物及对虾部的精子结构作了比较分析，初步探讨了日本沼虾的进化地位。具备丝状核物质和泡状核物质是日本沼虾成熟精子的重要特征之一，真虾部精子的细微结构可以作为分类依据。日本沼虾精子顶体结构较对虾部简单，在系统进化上，可能处于较低的地位。

Mitochondrial phylogenomics reveal the origin and adaptive evolution of the deep-sea caridean shrimps(Decapoda:Caridea)

The deep-sea is considered as the most extensive ecosystem on the Earth.It is meaningful for elucidating the life origins by exploring the origin and adaptive genetic mechanisms of the large deepsea organisms.Caridean shrimps have colonized and successfully adapted to deep-sea environments.They provide an ideal model to analyze the origin and adaptive evolution of modern deep-sea fauna.Here,we conducted the phylogenetic analyses of mitocho ndrial genomes(mitogenomes)from carideans,including 11 newly sequences reported in this investigation to explore the habitat origins,divergence times,and adaptive evolution of deep-sea(seamounts and hydrothermal vents)caridean shrimps.The results showed that the species of deep-sea Caridea formed a monophyletic group.Phylogenetic analysis supported that the deepsea caridean shrimps may originated from shallow sea.The hydrothermal vents alvinocaridid shrimps and Lebbeus shinkaiae from Thoridae underwent a second range expansion from seamounts to vent ecosystems.Estimates of divergence time showed that the caridean shrimps invaded into deep-sea at 147.75 Ma.The divergence of most of the modern seamount and hydrothermal vent species are in the late Cretaceous/early Tertiary.This may associate with the geological events of the Western Pacific,the climate change,and the global deep-water anoxic/dysoxic events during this period.Twenty-two potentially important adaptive residues were detected in the deep-sea shrimp lineage,which were located in atp6,atp8,cox1,cox3,cytb,nad2,nad4 l,and nad5.This investigation adds our understanding of the evolutionary history of deep-sea caridean shrimps,and provides insights into the mitochondrial genetic basis of deep-sea adaptation in this group.

Eualus heterodactylus sp.nov.,a new hippolytid shrimp from Chinese coast of the Yellow Sea(Crustacea,Decapoda,Caridea)

A new species from the caridean family Hippolytidae,Eualus heterodactylus sp.nov.is described and illustrated based on the specimens collected from Chinese coast of the Yellow Sea.The new species is a part of an informal species group characterized by the possession of epipods on the anterior three pairs of pereopods,and is distinguished from other species of this group by the dactyli of the third to fifth pereopods possessing distinctly stair-like flexor margins in males.

Complete mitochondrial genome of the Japanese snapping shrimp Alpheus japonicus(Crustacea:Decapoda:Caridea):Gene rearrangement and phylogeny within Caridea

The complete sequence of the mitochondrial genome of the Japanese snapping shrimp Alpheus japonicus Miers(Crustacea:Decapoda:Caridea) is presented here.A comparative analysis based on the currently available mitochondrial genomic data revealed many previously unknown characteristics of the mitochondrial genomes of caridean shrimps.The A.japonicus mitochondrial genome is 16487 bp long and contains the typical set of 37 metazoan genes.The gene arrangements in the mitochondrial genomes of four previously studied carideans(Macrobrachium rosenbergii,M.nipponense,M.lanchesteri and Halocaridina rubra) were found to be identical to the pancrustacean ground pattern;thus,it was considered that gene rearrangements probably did not occur in the suborder Caridea.In the present study,a translocation of the trnE gene involving inversion was found in Alpheus mitochondrial genomes.This phenomenon has not been reported in any other crustacean mitochondrial genome that has been studied so far;however,the translocation of one transfer RNA gene(trnP or trnT) was reported in the mitochondrial genome of Exopalaemon carinicauda.When the ratios of the nonsynonymous and synonymous substitutions rates(Ka/Ks) for the 13 protein coding genes from two Alpheus species(A.japonicus and A.distinguendus) and three Macrobrachium species(M.rosenbergii,M.nipponense,M.lanchesteri) were calculated,the Ka/Ks values for all the protein coding genes in Alpheus and Macrobrachium mitochondrial genomes were found to be less than 1(between 0.0048 and 0.2057),indicating that a strong purification selection had occurred.The phylogenetic tree that was constructed based on the mitochondrial protein coding genes in the genomes of nine related species indicated that Palaemonidae and Alpheidae formed a monophyly and shared a statistically significant relationship,(Palaemonidae+Alpheidae)+Atyidae,at the family level.

用16S rDNA序列初步探讨部分真虾类的系统发育关系

利用DNA序列测定技术测定了真虾下目7科8个种的线粒体16S rDNA部分序列, 与从GenBank检索得到的12个相关种的16S rDNA部分序列进行同源性比对,探讨其系统发育关系及16S rDNA在真虾类系统发育研究中的应用。比对序列长353bp,其中变异位点221个、简约信息位点180个。碱基转换替代速度比颠换替代速度慢。以螯虾下目的Aus- tropotamobius pallipes为外群构建了这20种真虾的系统发育关系分支图,结果展示:(1) 长臂虾科隐虾亚科的Anchistus custos远离长臂虾亚科分支。而且它的16S rDNA序列在Genbank中,首先与六足纲(Hexapoda)的昆虫比对上。(2)长臂虾科长臂虾亚科的两个近缘属Palaemon和Palaemonetes问的4个种混合相聚,说明传统形态分类中以大颚有无触须作为这两个属的属级形态鉴定特征尚需进一步审定。(3)鼓虾总科藻虾科的Exhipp- olysmata ensirostris与褐虾总科褐虾科的Crangon affinis处在同一分支,而没与鼓虾科的种类形成姐妹群。研究结果表明,16S rDNA片段的序列很适合研究真虾类的属间系统发育关系,而在研究属上高级阶元或种下阶元间的系统发生关系时较不敏感,因其变异对于种级水平显得过于保守,而对于科级以上阶元又显得太快。

云南华米虾属一新种(十足目:真虾次目:匙指虾科)

报道中国横断山区华米虾属一新种 ,即永胜华米虾Sinodinayongshengicasp nov ,对其形态特征作了详细描述 ,并与近似种进行了比较。

Oldest Asian Record of Snapping Shrimps(Malacostraca:Alpheidae)from the Kutch Basin,Western India and Associated Biota:Biostratigraphic,Paleoenvironmental and Paleoecological Significance

The oldest Asian record of alpheid shrimps,assigned to genus Alpheus,based on snapping claw fingertips from the Miocene Khari Nadi Formation in the Kutch Basin,western India reported herein,extends the fossil record of the family Alpheidae from Asia by~22 million years.An early Miocene(Aquitanian)age is estimated based on the associated assemblage of calcareous nannofossils,Sphenolithus disbelemnos,Cyclicargolithus floridanus,and Reticulofenestra haqii.The co-occurring microbiota includes bony fish otolith remains,identified as“genus Gobiidarum”,isolated teeth of Dasyatis rays,Sphyrna sharks,and teleosts,ctenoid and placoid scales,ostracods,belonging to the genera Paractinocythereis,Alocopocythere,Ruggieria,Aglaiocypris,Bairdoppilata,and echinoid spines.Taken together,the microfossil assemblage and data from chemical analyses using Energy Dispersive Spectroscopy,X-Ray Diffraction and Wavelength Dispersive X-Ray Fluorescence of host and associated lithologies suggests prevalence of a shallow(neritic)to coastal marine(intertidal)depositional paleoenvironment.The present investigation also provides the oldest fossil evidence on the co-occurrence of Alpheus and gobiids(based on otoliths)that strongly advocates that the mutualistic association between these animal groups had developed by the Aquitanian.

Report on the Hippolytidae Bate(sensu lato) from China seas

Thirty species belonging to 13 genera of three families in the Hippolytidae Bate, 1888(sensu lato) are reported in the present paper, including two new species and two newly recorded ones from the China seas. The two new species are named as Thinora leptochelus sp. nov. and Thor singularis sp. nov. Thinora leptochelus sp. nov. differs from the only knwon species of the genus, Thinora maldivensis(Borradaile, 1915), by the developed supraorbital tooth and the slender and cone-shaped chelae of the first 2 pereopods. Thor singularis sp. nov. can be dinstingershed from the other members of the genus Thor by the first 2 pereopods with epipods. The two newly recorded species from China seas are Eualus kikuchii Miyake & Hayashi, 1967 and Heptacarpus commensalis Hayashi, 1979.