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东北小鲵中枢神经系统形态学与组织学初步研究 总被引:4,自引:1,他引:3
本文应用脊椎动物神经标本制作法和HE染色法,对东北小鲵中枢神经系统的外部形态和组织学结构进行了初步研究,描述了东北小鲵神经系统形态和组织学结构的特点,并与无尾两栖类和爬行类相对比,探讨了有尾两栖类的进化地位。结果表明:与无尾两栖类(如蛙)相比,东北小鲵中枢神经系统中,大脑半球较小,结构较为原始,小脑结构简单,是两栖类中较为原始的类群。此外,东北小鲵开始具有了臂神经丛和骶神经丛,但没有爬行类的发达,可作为两栖类向爬行类进化的证据之一。 相似文献
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The effects of head shape variation on growth and metamorphosis in larval salamander (Hynobius retardatus) were examined by a laboratory experiment and a field experiment. In the laboratory experiment, each larva was fed equal amounts and was prevented from accessing others in both the solitary and group treatments, although chemical cues could be transmitted through water in the group treatment. The relative head width of larvae became larger in the group treatment during the early periods but having a large head width did not finally influence growth rate and days for metamorphosis. In the field experiment, larvae were allowed to contact each other directly in two density conditions. The enlarged relative head width was linked to high growth rate in the high-density treatment but not in the low-density treatment. The larval body size distribution in the high-density condition tended to be smaller, and there was a small proportion of large-sized individuals with a broad head width. Moreover, the small number of large larvae metamorphosed much earlier than the others. The mortality of larvae in high-density conditions was much higher than that in the low-density treatments. This would be a consequence of cannibalism in the high-density condition. From the experimental results obtained, it is argued that for the larvae of H. retardatus having a large head is an adaptive tactic that maximizes fitness, particularly in temporary ponds with an unpredictable environment and in crowded conditions. 相似文献
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大小等级和大小组合差异对盆养安吉小鲵幼体同种相残率的影响 总被引:3,自引:0,他引:3
用改变安吉小鲵 (Hynobiusamjiensis)幼体大小等级、盆养密度和饵料投放量的实验方法 ,研究这些生态要素对同种相残 (撕咬和吞吃 )的影响 ;同时结合Fuetal (2 0 0 3)的研究 ,比较了大小组合的差异对同种相残的影响。结果表明 ,①大小等级、密度与饵料量均显著地影响幼体的被吞吃率 :较小个体易被较大个体攻击 ;低饵料×高密度水平下 ,3个等级大小幼体的同种相残率都最高。②大小组合的差异显著影响幼体间的同种相残率 :不同大小组合的幼体间被吞吃率均显著大于相同大小组合 ,而被撕咬率反之。这证实了体形大小决定种群同种相残率的理论预测。 相似文献
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我国有尾动物分类中几个问题的研究 总被引:8,自引:2,他引:6
本文对有尾两栖类小鲵科Hynobiidae山溪鲵属、巴鲵属、小鲵属分类研究中的同物异名,以及属称的订正方面进行了进一步探讨,认为我国山溪鲵属应为5种,无唇褶山溪鲵B.cochranae应为北方山溪鲵Batrachuperus ti-betanus同物异名。巴鲵属是一个有效属称,义乌小鲵Hynobius yiwuensis应为中国小鲵H.chinensis的同物异名,黄斑拟小鲵Pseudohynobius flavonaculatus可以暂定为秦巴北鲵Ranodon tsinoaensis的同物异名。黑抓异鲵Xenobius melanonychus是否有效种有待确定。 相似文献
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为探讨猫儿山小鲵(Hynobius maoershanensis)和瑶山肥螈(Pachytriton intexpectatus)消化道结构的异同及5-羟色胺(5-HT)细胞的分布特征与食性、生活环境之间的关系,运用常规组织染色及免疫组织化学染色法对其消化道进行研究。结果显示,猫儿山小鲵和瑶山肥螈的消化道均包括食道、胃、十二指肠、回肠和直肠,但瑶山肥螈消化道长于猫儿山小鲵。猫儿山小鲵和瑶山肥螈的比肠长(即肠道长与头体长的比值)分别为0.57±0.03(n=5)和0.84±0.03(n=5)。两者消化道组织结构均由黏膜层、黏膜下层、肌层和外膜组成,主要差异在消化道黏膜层和肌层厚度。猫儿山小鲵的消化道黏膜层以胃体部最厚,达(712.82±37.67)μm(n=5),而瑶山肥螈则胃贲门部最厚,为(403.24±55.81)μm(n=5);二者消化道肌层均以胃幽门部最厚,但瑶山肥螈胃幽门部的肌层厚度比猫儿山小鲵的厚。二者消化道均有开放型和闭合型的5-HT细胞,但5-HT细胞的分布特征不同:猫儿山小鲵分布密度高峰位于直肠,低谷位于食道;瑶山肥螈则在十二指肠部位分布密度最高,直肠最低。综上所述,猫儿山小鲵和瑶山肥螈消化道形态学和组织学结构相似,二者肠道长占头体长的比值均不超过1,符合肉食性动物消化道短的特征。二者消化道5-HT细胞都具有内、外分泌功能,分布密度具有自身的特点,可能与它们的食物组成和生活环境不同有关。 相似文献
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