中国穿山甲与爪哇穿山甲甲片异速生长分析及其在司法鉴定中的应用
Allometry of scales in Chinese pangolins (Manis pentadactyla) and Malayan pangolins (Manis javanica) and application in judicial expertise
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摘要: 甲片对于穿山甲具有重要的防护功能, 其形态差异反映了穿山甲对不同环境的适应性进化。该文对35只中国穿山甲和119 只爪哇穿山甲甲片干重的异速生长模式进行了比较分析。结果表明, 爪哇穿山甲较中国穿山甲的甲片干重相对于头体长具有更高的异速生长速率(P=0.005):爪哇穿山甲的甲片干重相对于头体长具有正的异速生长速率(b=3.725, P=0.001), 而中国穿山甲的甲片干重相对于头体长则是等速生长(b=3.105, P=0.054)。这可能是由于较低纬度地区生活的爪哇穿山甲较较高纬度地区生活的中国穿山甲受到了更大的捕食压力影响。由于穿山甲甲片是一种重要传统中药材原料, 相关违法贸易案件频发, 且数量巨大。为推算穿山甲的涉案个体数量, 建议这两种穿山甲甲片干重与个体数的换算标准为中国穿山甲573.47 g, 爪哇穿山甲360.51 g, 但是当两种穿山甲大量甲片混合在一起时,建议采用上述两个参数的平均值, 即466.99 g,以此为穿山甲甲片贸易案件的司法鉴定以及司法审判中的定罪量刑提供依据。Abstract: Pangolins are unique mammals in that they possess scales that serve a protective biological function. As an important raw material of traditional medicine, illegal trades of these scales are frequent and difficult to investigate or prosecute. We used allometric models of dry weight of scales to compare 35 Chinese pangolins (Manis pentadactyla) and 119 Malayan pangolins (Manis javanica). Our results showed that the dry weight of scales increases significantly faster with the length of head and body in Malayan pangolins (P=0.005), while dry weight of scales is positive (slope=3.725) in Malayan pangolins but isometric (slope=3.105) in Chinese pangolins. The differences in morphology between these species may reflect an evolutionary adaptation to different environments; Malayan pangolins in tropical regions appear to suffer from greater predation pressure than Chinese pangolins in temperate regions. We advise the conversion standards between dry weight of scales and number of individuals as 573.47 g in Chinese pangolins and 360.51 g in Malayan pangolins respectively, and when two are mixed together, average above two parameters of the median at 466.99 g. We propose these measurements be used as judicial evidences in forensic identification of related cases.