The developmental stages of Lernaeocera Branchialis (Linn.)
The developmental stages of Lernaeocera Branchialis (Linn.)
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Lernaeocera Branchialis (Linn.) 的发育阶段
DOI：
10.1017/s0025315400055090
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发表时间：
1942
影响因子：
1.2
通讯作者：
N. G. Sproston
中科院分区：
文献类型：
--
作者：
N. G. Sproston
本文描述了鳃卷尾虫一系列发育阶段的形态。在到达gadoid（最终）宿主之前，要经过七个阶段。详细讨论了口管和附属物的结构，并与近缘属进行了比较。在肉棱皮龟上，游离的单无节幼体和桡足幼体阶段紧接着是四个chalimus阶段;这些显示出一些去分化，尽管分割没有丢失。一个解释是为chalimus的奇特的悬浮机制。第二次去分化是在第二个发育良好的远洋阶段之后，在这一阶段中，达到了成虫的形态，并发生了交配。有些不规则的退化变态的细节成熟的女性在gadoid主机。Lernaeocera的体长增长率有规律地下降，直到成年形式（阶段VII）的假设。在这方面，它类似于自由生活的桡足类Diaptomus，Eurytemora和Calanus，但与Caligus centrodonti形成强烈对比，Caligus centrodonti的增长率一直增加到第四个chalimus阶段。在后者的这个阶段，生长速度有明显的加速，没有伴随着形状的任何变化或任何其他的不连续性，而在Lernaeocera中，在发育中有早期的不连续性，然而，当用图形表示时，生长速度是连续的：它是一条直线，而不是根据我们对高等甲壳动物的知识所预期的对数曲线。女性的体型比男性的大：女性的体型与下一阶段的男性重叠。在一个阶段组中的幼虫的大小变化不是季节性的，并提供了巨大的幼虫的解释。类似的lernaeocerid幼虫和男性的Lernaeocerabranchialis在Pleuronectes flusus上发现Solea solea和Cyclopterus lumpus。没有特征的属或特定的意义，可以找到将服务Ot分开他们从Lernaeocera branchialis，使他们的身份是不确定的。
The morphology of a complete series of developmental stages of Lernaeocera branchialis is described. Seven stages are passed through before reaching the gadoid (final) host. The structure of the mouth tube and appendages is discussed in detail and compared with those of related genera in which the resemblances are close. The free single nauplius and copepodid stages are immediately followed by four chalimus stages on Pleuronectes flesus; these show some dedifferentiation though segmentation is not lost. An explanation is given for the peculiar suspensory mechanism of the chalimus. A second dedifferentiation follows the second well-developed pelagic phase in which the adult form is attained and copulation takes place. Some irregularity is noted in the details of the retrogressive metamorphosis of the maturing female on the gadoid host. The rate of increase in body length in Lernaeocera decreases regularly up to the assumption of the adult form (stage VII). In this respect it is similar to the free-living copepods Diaptomus, Eurytemora and Calanus, but is in strong contrast to Caligus centrodonti which has an increasing growth rate up to the fourth chalimus stage. In the latter at this stage there is a marked acceleration in the growth rate unaccompanied by any change in shape or any other discontinuity, whereas in Lernaeocera there are early discontinuities in development, yet the growth rate is continuous when expressed graphically: it is a straight line rather than a logarithmic curve as would be expected from our knowledge of the higher Crustacea. The size of the female is greater than that of the male: that of the female overlapping the male of the succeeding stage. Variations in size of the larvae in a stage group are not seasonal, and an explanation is offered for giant larvae. Similar lernaeocerid larvae and males to those of Lernaeocera branchialis on Pleuronectes flesus were found on Solea solea and Cyclopterus lumpus. No characters of generic or specific significance could be found which would serve o t separate them from Lernaeocera branchialis so that their identity is not determined.