Tracing functional adaptation in African cichlid fishes through morphometric analysis of fossil teeth: exploring the methods
Tracing functional adaptation in African cichlid fishes through morphometric analysis of fossil teeth: exploring the methods
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DOI：
10.1007/s10750-015-2218-0
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发表时间：
2015-08-01
期刊：
影响因子：
2.6
通讯作者：
Verschuren, Dirk
中科院分区：
文献类型：
--
作者：
Dieleman, Jorunn;Van Bocxlaer, Bert;Verschuren, Dirk
东非查拉湖火山口的沉积档案中包含了至少在过去25,000年间丰富的慈鱼化石牙齿。在这里，我们利用对查拉湖现存的两种罗非鱼的口腔牙齿进行形态计量分析，以探索在湖泊化石记录中追踪适应修改慈济鱼营养装置的可行性。我们比较了半标志性分析(SLM)和椭圆傅立叶分析(椭圆傅立叶分析)在捕捉口腔牙冠形态变异方面的性能，发现SLM结合牙轴测量确保了与全身标志性分析的一致性。全身和牙齿的形态数据都可以区分本土的罗非鱼和最近引进的克罗格韦罗非鱼。这两个物种都有外部排二尖齿和内排三尖齿的口腔下巴排列，但猎人的牙齿通常比克洛格鲁人的牙齿更细长，主要尖端按比例更高，这表明资源分配是精细的。对三个化石样本的探索性分析表明，现代奥里奥罗米斯的主要牙齿类型也出现在化石记录中。它们的整体形态变异在很大程度上受到当代牙齿所占据的形态空间的限制，这表明古代种群与其可能的后代O.Hunteri之间存在密切的功能关系。
The sedimentary archive of Crater Lake Challa in East Africa contains abundant fossil teeth of cichlid fishes throughout at least the last 25,000 years. Here, we use morphometric analyses of oral teeth from the two extant Oreochromis species inhabiting Lake Challa to explore the feasibility of tracing adaptive modification of the cichlid trophic apparatus in the lake's fossil record. We compared the performance of semi-landmark analysis (SLM) and elliptic Fourier analysis in capturing morphological variation in oral tooth crowns, and found that SLM, supplemented with tooth shaft measurements, ensured consistency with whole-body landmark analyses. Whole-body and tooth morphology data both allowed to discern between the indigenous Oreochromis hunteri and the recently introduced Oreochromis korogwe. Both species have an oral jaw arrangement of outer-row bicuspid and inner-rows tricuspid teeth, but O. hunteri has generally more slender teeth with a proportionally taller major cusp than O. korogwe, suggesting fine-scaled resource partitioning. Exploratory analysis of three fossil samples showed that the major tooth types of modern-day Oreochromis are also represented in the fossil record. Their total morphological variation is largely restricted to the morphospace occupied by contemporary teeth, suggesting a close functional relationship between ancient populations and their likely descendant, O. hunteri.