利用形態特徵與粒線體DNA探討Metaphire formosae種群蚯蚓的系統分類、生物地理與演化

Systematics, biogeography, and evolution of the earthworms in the Metaphire formosae species group inferred from morphology and mitochondrial DNA sequences

張智涵(Chih-Han Chang)

指導教授 ： 陳俊宏

國立臺灣大學/生命科學院/動物學研究研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01065

摘要

本研究在屬於環毛蚓（the pheretimoid earthworms、Pheretima auct.）的腔環蚓屬（Metaphire）中建立了一個新的M. formosae種群，並探討此種群的系統分類、生物地理與演化。研究的結果將此種群的物種數由6種提升為12種，其中11種為台灣特有種，包括本研究中所發表的3個新種。研究的結果顯示，台灣的M. formosae種群蚯蚓的祖先種在中新世晚期來到台灣島上，並快速地播散到全島。在距今5.0∼2.5百萬年前的這段時間，台灣島快速隆起，此祖先種的不同族群被因為造山運動而新形成的山脈與河流快速地隔離，接著產生遺傳分化，最後種化成不同的物種。此外，在距今2.5百萬年前之後的這段時間，台灣島的抬升所產生的地理隔離，則進一步地造成了種內不同族群間的遺傳分化。以M. yuhsii為例，此物種的二個族群在距今2.5百萬年前淡水河形成時被分隔開來，並漸漸地產生遺傳分化。另一方面，研究的結果顯示，M. formosae種群中的holandy來自proandry，因此，在環毛蚓的屬內分群中，睪丸的數目與位置並不是一個好的分類依據。建議未來環毛蚓系統分類的修訂，必須以分子譜系分析為基礎。

關鍵字

蚯蚓 ； 系統分類 ； 生物地理 ； 演化 ； 親緣地理 ； 巨蚓科 ； 環毛蚓 ； 腔環蚓 ； 福爾摩沙腔環蚓種群 ； 台灣

並列摘要

A new Metaphire formosae species group in the genus Metaphire of the pheretimoid earthworms (Pheretima auct.) is proposed in this study, and the systematics, biogeography, and evolution of this species group are also concerned. The species abundance of this species group was increased from 6 to 12. Among these species, 11 are endemic to Taiwan, including three new species described in this study. The results suggested that the ancestor of the Taiwanese species arrived Taiwan during the late Miocene, and then dispersed throughout this island. During the rapid uplift of Taiwan between 5.0~2.5 MYA, different populations of the ancestor species were rapidly and continuously isolated by the mountains and rivers that formed due to orogenesis in this period. The isolation initiated genetic differentiation and finally caused speciation of the M. formosae species group. In addition, the uplift of Taiwan after 2.5 MYA caused intraspecific genetic differentiation among geographically isolated populations of the M. formosae species group. For instance, in M. yuhsii, a member of this species group, two populations started to differentiate genetically about 2.5 MYA due to the formation of the Tamsui River, which served as a geographical barrier between the two populations. On the other hand, the results suggested that holandry derives from protandry in the M. formosae species group. Therefore, the use of testis conditions in intrageneric grouping in pheretimoid earthworms is not appropriate. The revision of the pheretimoid systematics needs further investigation using molecular phylogenetic approaches.

並列關鍵字

earthworms ； systematics ； biogeography ； evolution ； phylogeography ； Megascolecidae ； pheretimoid earthworms ； Pheretima ； Metaphire ； Metaphire formosae species group

參考文獻

陳毅翰、張智涵、陳俊宏（2003）。宜蘭縣蚯蚓種類與分佈。生物科學46卷，56-65頁。

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