Feeding in dominant Antarctic copepods - does the morphology of the mandibular gnathobases relate to diet?
Feeding in dominant Antarctic copepods - does the morphology of the mandibular gnathobases relate to diet?
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DOI：
10.1007/s00227-004-1452-1
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发表时间：
2005-02-01
期刊：
影响因子：
2.4
通讯作者：
Schnack-Schiel, SB
中科院分区：
文献类型：
--
作者：
Michels, J;Schnack-Schiel, SB
这项研究阐明了下颌齿基的形态和稳定性对南极桡足动物饮食的重要性。利用扫描电镜对南大洋桡足类优势种Calanoides acutus、Calanus propinquus、Ctenocalanus citer、Rhincalanus gigas、Metridia gerlachei、Stephos longipes、Microcalanus pygmaeus和Paraeuchaeta antarctica的齿基形态进行了详细研究。acutus、C. propinquus和C. citer的下颌齿基牙齿相对较短且紧密。这些物种主要以硅藻为食，并且能够通过直接压力用它们的下颌齿基敲碎硅藻硅片。相比之下，南极南极龙的下颌齿基的牙齿又长又尖。这一物种的营养主要由其他较小的桡足类动物组成。移动的猎物可以用牙基串住，然后最后切碎。与其他已调查的桡足类物种相比，南极南极龙的下颌齿基明显有更多的小刚毛。这些刚毛可能与受体有关，可以用来定位猎物。巨齿龙和巨齿龙的齿基形态介于南极巨齿龙与尖牙龙、propinquus和citer巨齿龙之间。根据其齿基的形态，桡足类物种S. longipes迄今为止被发现主要以浮游植物为食，主要是冰藻，也必须被认为是浮游动物的捕食者。调查显示，pygmaeus的齿基具有令人惊讶的长而尖的牙齿，这表明该物种很可能以植物和浮游动物生物为食。虽然C. propinquus、R. gigas、M. gerlachei和S. longipes的雄性下颌齿基与各自物种的雌性具有相同的形态，但在其他四个被调查的桡足类物种中，雄性下颌齿基减少（C. acutus、C. citer和M. pygmaeus）或完全缺失（P. antarctica）。除M. gerlachei外，所有被研究物种的齿基牙齿由与齿基其余部分不同的材料组成。这种物质似乎是硅酸盐，它可能增强了牙基牙齿的稳定性。
This study should clarify the importance of morphology and stability of the mandibular gnathobases for the diet of Antarctic copepod species. The gnathobase morphology of the dominant copepod species Calanoides acutus, Calanus propinquus, Ctenocalanus citer, Rhincalanus gigas, Metridia gerlachei, Stephos longipes, Microcalanus pygmaeus and Paraeuchaeta antarctica from the Southern Ocean was investigated in detail by means of a scanning electron microscope. The mandibular gnathobases of C. acutus, C. propinquus and C. citer have relatively short and compact teeth. These species feed mainly on diatoms and are able to crack the silicious diatom frustules with their mandibular gnathobases by directed pressure. In contrast the teeth of the mandibular gnathobases of P. antarctica are very long and pointed. The nutrition of this species consists predominantly of other smaller copepod species. The motile prey can be held by skewering, using the gnathobases, and then eventually minced. The mandibular gnathobases of P. antarctica have notably more small bristles than those of the other investigated copepod species. These bristles are probably associated with receptors and could serve to locate the prey. The morphology of the gnathobases of R. gigas and M. gerlachei is between that of P. antarctica on the one side and that of C. acutus, C. propinquus and C. citer on the other. Based on the morphology of its gnathobases the copepod species S. longipes, which has to date been found to feed primarily on phytoplankton, mainly ice algae, must also be considered a zooplankton feeder. The investigation showed that M. pygmaeus has gnathobases with surprisingly long and pointed teeth, indicating that this species very probably feeds both on phyto- and on zooplankton organisms. While the mandibular gnathobases of the males of C. propinquus, R. gigas, M. gerlachei and S. longipes have the same morphology as the females of the respective species, in the other four investigated copepod species the males have reduced (C. acutus, C. citer and M. pygmaeus) or completely missing mandibular gnathobases (P. antarctica). The teeth of the gnathobases of all studied species with the exception of M. gerlachei consist of a different material than the remaining parts of the gnathobases. This material seems to be silicate, which probably enhances the stability of the gnathobase teeth.