ON THE LYMPHATIC SYSTEM OF ASCAPHUS - ITS EVOLUTIONARY SIGNIFICANCE
ON THE LYMPHATIC SYSTEM OF ASCAPHUS - ITS EVOLUTIONARY SIGNIFICANCE
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DOI：
10.1002/ar.1091320309
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发表时间：
1958-01-01
影响因子：
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通讯作者：
KAMPMEIER, OF
中科院分区：
文献类型：
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作者：
KAMPMEIER, OF
由于Ascaphus在分类上处于无尾猿谱系的基础，因此对这种两栖动物的淋巴系统进行了研究，以确定其在脊椎动物比较形态学中的地位和意义。由于该系统的基本平面图在幼虫期比在变质后阶段更清楚地显示出来，因此可供检查的蝌蚪系列（18.5至46毫米）是相当充足的。在它的淋巴系统中，Ascaphus代表了一个“缺失的环节”（在可接受的意义上），是尾尾目（或亚纲）和无尾目之间的过渡形式。在其淋巴心脏的数字配置。Ascaphus比典型的无尾猿更接近有尾两栖动物（尾猿）。值得注意的是，残留的淋巴心脏可能存在于小蝌蚪的身体部分，直接位于含有功能性前淋巴心脏的身体部分。在迄今为止所研究的无尾动物中，Ascaphus具有独特的尾猿特征，心脏淋巴窦流入静脉窦。两栖动物前后淋巴心脏起源模式的差异似乎可以用它们不同的形成时间来解释，因此，在发育事件的前后梯度过程中，内在环境的变化可以解释。这一认识可能为解释有关淋巴的起源、发展和生长的相互矛盾的观察和假设提供线索。从鱼类到人类的脊椎动物淋巴系统的比较形态学研究得到的证据进一步表明，事件的前后梯度，无论是渐进的还是后退的，对系统发育和个体发育都是有效的。这在多大程度上代表了有机进化的一般原则，还有待进一步研究。将这条古老的躯干轴向淋巴管命名为椎下淋巴管（或直立动物的椎前淋巴管）比“胸管”这个模棱两可的名称更为合适。
Because of the taxonomic position of Ascaphus at the base of the anuran lineage, a study of the lymphatic system of this amphibian was undertaken to determine its place and significance in the comparative morphology of vertebrates. Since the basic plan of this system is more clearly revealed in larval than in post-metamorphic stages, the series of tadpoles available for examination (18.5 to 46 mm) were quite adequate. In its lymphatic system, Ascaphus represents a "missing link" (in the acceptable sense), a transitional form between the orders (or subclasses) Urodela and Anura. In numerical disposition of its lymph hearts. Ascaphus comes closer to the tailed amphibians (urodeles) than does the typical anuran. Significantly, a vestigial lymph heart may be present in Ascaphus tadpoles in the body segments directly following that containing the functional anterior lymph hearts. Unique among Anura studied thus far, Ascaphus possesses a characteristic urodelan feature a cardiac lymph sinus that empties into the sinus venosus. Diversity between the modes of origin of the anterior and the posterior lymph hearts in Amphibia appears to be explained by their different times of formation[long dash]hence, by the changing intrinsic environment during the antero-posterior gradient of developmental events. This recognition may offer a clue to explaining the conflicting observations and hypotheses concerning the origin, development and growth of lymphatics. The evidence derived from the study of the comparative morphology of the lymphatic system of vertebrates, from fish to man, suggests further that the antero-posterior gradient of events, both progressive and regressive, is as valid for phylogeny as it is for ontogeny. To what extent this represents a general principle of organic evolution bears further examination. The designation lymphatica subvertebralis (or preverte-bralis, in animals of upright posture) is more appropriate than the ambiguous name "ductus thoracicus" for this ancient axial lymph conduit of the trunk.