罗氏沼虾溞状幼体的形态特征

罗氏沼虾的幼体变态发育需经过多次蜕皮,每次蜕皮均伴随形态及附肢特征的改变。采用显微观测摄像法对Z1-Z12各期幼体样本30尾进行观察测量,结果显示:Z2与Z1在复眼上存在较大的差异;Z3的主要特征为尾节与第六腹节分界;Z4尾扇分为内肢和外肢,均具羽状刚毛;Z5无腹足,尾节狭长,且末端平直;Z6的腹部出现腹足萌芽;Z7腹肢芽延长分为内外肢,Z7与Z8的分期特征主要位于第1触角的内鞭、外鞭的分枝上;Z8的第1、第2对步足具不完全的螯;Z9第1、2对步足具完全的螯;Z10后额角上缘的齿刻增多,Z11第1触角内鞭和外鞭分节数量比Z10多;Z12的形态与成虾相似,额角上、下缘均有齿刻。

Morphological Characteristics of Zoaea Larva of Macrobrachium rosenbergii

From hatching to metamorphosis for larvae of Macrobrachium rosenbergii,it experiences the molting process many times accompanying the changes of morphology and appendage characteristics.Through microscopic observation and photography on 30 samples of Z1-Z12 larvae,the results show that there are big differences in compound eye between Z1 and Z2.The main features of Z3 is demarcation of telson and abdominal segment 6.Tail fan of Z4 is divided into endopodite and exopodite and both have natatory setaes.There was no abdominal foot in Z5 with a long-narrow telson and straight terminal,there is proleg germination occurred in abdomen of Z6,and pleopod germination of Z7 was prolonged to divide into endopodite and exopodite.The characteristics between Z7 and Z8 are located at branch of antennule inner and outer flagellum.The first and second pairs of periopods have incomplete cheliped in Z8,but complete cheliped in Z9.The gear carve on upper edge of post frontal angle increase during the period of Z10.The number of segmentation of antennule inner and outer flagellum in Z11 is more than Z10.The morphology of Z12 is the same as the adult shrimp of Macrobrachium rosenbergii,both upper edge and lower edge of frontal angle have gear carves.