马氏沼虾蚤状幼体发育特征及其与罗氏沼虾幼体的形态差异

马氏沼虾(Macrobrachium malcolmsonii)的幼体从孵化到变态为幼虾要经过多次蜕皮,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马氏沼虾Z1-Z12各期幼体样本30尾进行了观察,测量结果表明Z2与Z1在复眼上存在较大差异,Z3与Z2、Z4与Z5的主要分期特征均位于尾节上,Z6的腹部出现腹足萌芽,Z7与Z8的形态差异在于第一触角内鞭和外鞭的附肢变化,判别Z9-Z12的主要分期依据为步足、腹足和额角形态。因此通过观察Z1-Z12幼体第1触角上的内鞭和外鞭,第2触角上的触角鞭和触角片,头胸甲上的额角、背刺、复眼和第1、2对步足,腹部的附肢、尾节和尾扇等形态变化,及测定各期幼体附肢的分节数和刚毛数等可量性状上的差异,可为马氏沼虾蚤状幼体分期提供生物学依据;此外还对马氏沼虾与罗氏沼虾幼体的形态差异进行了比较,通过测定幼体触角鞭的分节数量,为两种沼虾幼体之间的鉴别提供参考数据。  

MORPHOLOGICAL CHARACTERISTICS AND DIFFERENCE ON ZOEA LARVAE OF MACROBRACHIUM MALCOLMS ONII AND MACROBRACHIUM ROSENBERGII

From hatching to metamorphosis for larvae of Macrobrachium malcolmsonii, the larvae had experienced themolting process twelve times accompany with changes of Morphology and appendage characteristics. Through microscopicobservation and photography on 30 samples from Z1 to Z12 larvae, the results showed that there were big differencesin compound eye between Z1 and Z2. The main characters were located on the telson between Z3 and Z2, Z4 and Z5.There was proleg germination occurred on abdomen of Z6. The morphological variations between Z7 and Z8 lain inchanges of antennule inner and outer flagellum appendage. The main periodical standards to discriminate Z9 and Z12were morphology of periopods, proleg and rostrum. Therefore, it could provide biological basis in different zoea stagesof Macrobrachium malcolmsonii by means of observation on morphological variations such as the inner and outerflagellum of the first antennule, flagellum and antennal scale of the second antenna, rostrum, dorsal spur, compound eye,the first and second legs on the carapace, pleopod, telson, tail fan from Z1 to Z12 larvae, as well as determination of morphometriccharacter of the larvae such as the number of segments, quantity of seta during the period from Z1 to Z12stages. In addition, morphological variations of zoea larvae of Macrobrachium malcolmsonii have been compared withMacrobrachium rosenbergii, which could provide reference to identify these two kinds of zoea larvaes by measuring thenumber of antennal flagellum segmentation.