我們曾分別在2008年10月與2009年4月各獲得一隻"鋸背圓龜"(在市面上又叫鋸背緣龜或亞洲葉龜), 但是當時對牠們的身份並不是十分在意. Cyclemys這個屬的東西通常都是以"Cyclemys dentata"這樣的名稱在市面上流通, 但是自從Fritz et al (2008)與Prashag et al. (2009)的兩篇論文之後, Cyclemys的種級多樣性變高了, 這也意謂著鑑定寵物市場上流通的同屬物種更加困難了. 鑑定這些物種的困難之處除了缺乏有效的形態檢索資訊之外, 寵物市場上流通個體的真正採集來源多半不可信也是因素之一. 從印尼進口的生物並不一定就是印尼產的, 而以印尼幅員之廣大, 所屬島嶼跨越兩個生物地理區來說, 光憑"印尼來的"這個資訊是無法提供任何正確鑑定線索的. 比較我們在2008年10月所獲得的個體(上圖)與2009年4月獲得的個體(下圖)發現兩者似乎有不小的差異, 但是兩者都是以"鋸背圓龜"的名義進口的. 這是怎麼一回事呢? 我們先看看這兩篇論文說些什麼: Fritz et al. (2008)年那篇文章的主旨是這樣的. Cyclemys這個屬的鑑定一向困難, 而在過去在整個東南亞的大多數區域所發現的圓龜也多半被當成"dentata"這個物種. Fritz等人使用了mtDNA, nuclear DNA與ISSR加上形態資訊重新評估這個屬的種級多樣性. 結果他們發現這個屬可以分為兩大群, 一群具有黃色的腹甲(Cyclemys atripons, C. dentata, C. pulchristriata)還有深色腹甲的類群. 而具有深色腹甲的分支群則包含了一般認為形態的個體變化很大的C. oldhamii( = tcheponensis)以及三個新物種C. enigmatica, C. fusca與C. gemeli. 而可能由於漸滲雜交的關係, C. enigmatica的mtDNA序列與共域分布的C. dentata並沒有什麼兩樣, 但兩者在nuclear genome方面則相差甚大. 這篇文章也指出一般的多變量分析無法提供形態測量學證據來區別這些龜種, 也就是說一定要輔以分子工具才有可能正確地鑑識牠們的身份. Prashag et al.(2009)的文章則側重於C. gameli這個物種的確認, 他們也認為光憑形態是無法鑑定這些物種的. 所以, 我們所飼養的圓龜倒底是什麼東西呢? 其實Fritz et al.的文章仍然提供了一個檢索表用以鑑識這些物種:Key for adult Cyclemys (參見這邊的說明術語)
- 1 Plastron entirely yellow or prevalent plastral colour yellow; femoral mid-seam shorter than or equal to anal mid-seam; anal notch small to wide and acute-angled to obtuse-angled...2
- 1' Plastron entirely dark (brown or black) or prevalent plastral colour dark (brown or black); femoral mid-seam approximately equal to or longer than anal mid-seam; anal notch wide, obtuse-angled...4
- 2 Femoral mid-seam shorter than anal mid-seam; anal notch small and acute-angled; throat striped or with light and dark vermiculations, light head and neck stripes narrow (in live specimens reddish); in aged individuals bridge never covered by massive black bar...Cyclemys dentata (Gray, 1831)
- 2' Femoral mid-seam shorter than or equal to anal mid-seam; anal notch small to wide and acute-angled to obtuse-angled; throat uniformly light coloured, light head and neck stripes wide (in live specimens yellow or salmon); in aged individuals bridge may be covered by massive black bar...3
- 3 If black radiating pattern is present on plastron, radiating lines long and thin...Cyclemys atripons
- 3' If black radiating pattern is present on plastron, radiating lines short and stout ...Cyclemys pulchristriata
- 4 Crown of the head speckled; shell rectangular when viewed from above; all juveniles and adults from the eastern part of the range with conspicuous head and neck stripes, adults from the western part of the range unstriped...Cyclemys oldhamii
- 4' Crown of the head uniform...5
- 5 Crown of the head brown, but not lighter than temporal region; shell elongated to rectangular...Cyclemys gemeli
- 5' Crown of the head lighter than temporal region; shell ovoid when viewed from above...6
- 6 Crown of the head uniformly greenish yellow to light brown; palate and tongue of specimens in alcohol grey, sometimes with darker grey spots; northern and central Myanmar...Cyclemys fusca
- 6' Crown of the head uniformly copper or light brown; palate and tongue of specimens in alcohol pure white; southern Malay Peninsula and Greater Sunda Islands...Cyclemys enigmatica
