Assessment of Nonmetric Skull Characters of the Franciscana (Pontoporia blainvillei) in Determining Population Differences
Assessment of Nonmetric Skull Characters of the Franciscana (Pontoporia blainvillei) in Determining Population Differences
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DOI：
10.1578/am.34.3.2008.338
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发表时间：
2008-01-01
期刊：
影响因子：
1.2
通讯作者：
Praderi, Ricardo
中科院分区：
文献类型：
--
作者：
Trimble, Micaela;Praderi, Ricardo
弗朗西斯卡海豚（学名：Pontoporia blainvillei）是巴西、乌拉圭和阿根廷大西洋沿岸的一种特有的小型海豚，由于其在整个分布区的手工捕鱼网中的偶然死亡而引起了保护问题。管理小型鲸目动物的一个重要步骤是确定所涉种群，因为每一个已确定的种群都需要作为一个单独的单位进行评价和处理。自1991年以来，已发现不同地区的Franciscanas之间存在形态和遗传差异。非公制字符（即，由离散状态编码，也称为质量性状）已被用于分析50多种哺乳动物物种的群体分化，因为已经假定它们受到最小的选择压力。本研究的目的是确定潜在的有用的非度量头骨字符的franciscana从不同地点的个人之间的比较，以调查这些特征的地理变异，并确定其频率在乌拉圭海岸的个人。对国家自然历史和人类学博物馆（乌拉圭蒙得维的亚）收藏的115个鲸类头骨的26个特征进行了检查。潜在存在的字符依赖于身体的长度，性别和时间段进行了检查。共有12个字符被排除在随后的分析：7个没有足够的变量，4个是依赖于身体的长度，和一个显示性二型。只剩下14个字符，并计算了它们的频率。它们都不依赖于时间。由于在本研究中发现的潜在有用的非测量头骨特征数量较少，因此该技术作为弗朗西斯卡纳人群评估的附加工具的实用性尚不确定。作者给出了在种群分化研究中使用非度量性状的一般方法学建议。
The franciscana (Pontoporia blainvillei) is a small endemic dolphin of the Atlantic coast of Brazil, Uruguay, and Argentina that presents conservation problems because of its incidental mortality in nets of artisanal fisheries throughout its entire distribution. An important step in managing small cetaceans is to define the populations involved because each identified population requires evaluation and treatment as a separate unit. Since 1991, morphological and genetic differences among franciscanas of different regions have been detected. Nonmetric characters (i.e., coded by discrete states and also known as qualitative traits) have been employed for the analysis of population differentiation of more than 50 mammal species because it has been assumed that they are exposed to minimum selection pressure. The aim of this study was to identify potentially useful nonmetric skull characters of the franciscana for comparison among individuals from different locations in order to investigate geographic variation in these traits and to determine their frequencies in individuals of the Uruguayan coast. Twenty-six characters were examined for 115 skulls belonging to the cetacean collection of the National Museum of Natural History and Anthropology (Montevideo, Uruguay). The potential existence of character dependence on body length, sex, and time period was examined. A total of 12 characters were excluded from Subsequent analyses: seven were not sufficiently variable, four were dependent on body length, and one showed sexual dimorphism. Only 14 characters were remaining, and their frequencies were calculated. None of them was dependent on time period. Due to the low number of potentially useful nonmetric skull characters found in this study, the utility of this technique as an additional too] for franciscana population assessment is uncertain. The authors give some general methodological recommendations for use of nonmetric characters in population differentiation studies.