麗紋石龍子（Plestiodon elegans）在臺灣的族群遺傳分化與隱蔽種

Population genetic divergence and cryptic species of Plestiodon elegans in Taiwan

林雨昕(Lin Yu-Hsin)

指導教授 ： 林思民

國立臺灣師範大學/理學院/生命科學系/碩士(2022年)

https://doi.org/10.6345/NTNU202200405

摘要

廣泛分布的物種在現今空間上的遺傳結構分布，往往是由過去的地質事件或氣候事件所造成。受惠於分子技術的進步，某些在遺傳上有分化，但在形態上卻非常相似的隱藏譜系得以被發現，顯示兩棲爬行動物在台灣的物種多樣性是被低估的。隱蔽種的發現對於演化理論 、生物地理和保育政策的制定有著深遠 的影響，也能進而探究其種化機制或是種化歷史。麗紋石龍子（ Plestiodon elegans）廣泛分布於中國大陸 、 釣魚台列嶼 、 澎湖以及台灣本島， 是台灣唯一分布海拔跨越 0到 3000公尺左右的蜥蜴，然而對此物種的族群遺傳結構研究甚少。為了 瞭解麗紋石龍子在台灣的遺傳分化，我們在全島 包含 1700公尺以上高海拔地區 、 澎湖和龜山島，以及代表中國族群的馬祖進行採集， 利用定序取得遺傳資料，包括粒線體的cytochrome b和 ND1以及核基因的 RAG-1和 PRLR片段，重建親緣關係，比較各地族群的遺傳差異和分化時間，並進行形態分析。分子遺傳結果顯示在粒線體片段中，台灣東西部的麗紋石龍子並不呈現單系群。台東附近由低到高海拔的族群為一獨立的單系群，且與台灣其餘族群的遺傳距離高於其他在琉球群島的幾個近緣種。而核基因由於序列相對保守，較無可供辨識的序列特徵 。形態分析結果顯示，台東族群的頭部鱗片 包括眶前鱗、眶後鱗、上睫鱗、下唇鱗、頸鱗）、前肢第二指指墊數和後肢第二、第四趾趾墊數 (RFII、RTII、 RTIV)、吻肛長（ SVL）以及 頭深 （HD）皆顯著不同於台灣其餘族群。綜合以上，麗紋石龍子在台東的族群應為一獨立的新種，其分類地位必須進行重新的描述。

關鍵字

親緣關係樹 ； 遺傳結構 ； 隱蔽種 ； 麗紋石龍子

並列摘要

The elegant five-lined skink (Plestiodon elegans) is widely distributed in Mainland China, Senkaku island, Penghu, and Taiwan and is the only lizard in Taiwan with an altitude range from 0 to 3000 meters. However, the genetic structure of this species within the island has never been well addressed. In order to investigate the genetic divergence of populations in Taiwan, we sampled a wide range around the island including high elevation areas (above 1700 meters), two offshore islets (Penghu and Gueishan island), and Matsu Archipelago which represents population from Mainland China. Genetic data was applied to reconstruct the phylogenetic relationship and divergence time among the clades and their closely related species, while morphology of the samples were analyzed. Molecular genetic structure demonstrated that the western and eastern populations do not represent a monophyletic group in mitochondrial DNA. The populations near Taitung are a distinct lineage, with its genetic distances from other populations in Taiwan higher than that among other species distributed in Japan and Ryukyu islands. Nuclear genes are relatively conserved and have no identifiable sequence features. Morphological analyses showed that head scales (PrO, PoO, SuC, IL, Nu), subdigital lamellae on Finger-II, Toe-II, and Toe-IV (RFII, RTII, RTIV), snout-vent length (SVL), and head depth (HD) of Taitung population showed significantly differences from the other populations in Taiwan. This population should be regarded as an independent species.

並列關鍵字

cryptic species ； genetic structure ； phylogenetic tree ； Plestiodon elegans

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