本論文已被瀏覽 497 次， [ ] 54 次，[ ] [ ]
雜色尖嘴魚 (隆頭魚科) 無骨骼性雙型暨近緣種之親緣關係
隆頭魚科 (Labridae) 為熱帶珊瑚礁海域中種類最豐富且色彩鮮豔的魚類科別，多數種類具有先雌後雄的性轉變以及外部形態上明顯的性雙型。雜色尖嘴魚 (Gomphosus varius) 為隆頭魚科中性雙型相當顯著的種類之一，包括雌雄間的體色以及尾鰭形狀的外部形態差異，但目前並未有任何關於雜色尖嘴魚骨骼性雙型的內部形態差異文獻。研究指出某些魚類的雄性會快速揮舞其胸鰭並與相連部位之骨格摩擦產生聲音以求偶，雜色尖嘴魚也有類似的求偶行為，但不曾有研究指出其雄魚之胸鰭與相連部位之骨骼是否有特殊構造。另外，由於各文獻中關於雜色尖嘴魚尾鰭形狀的描述不盡相同，以及曾於其他隆頭魚科魚類發現骨骼性二色，基於以上動機，本研究認為雜色尖嘴魚之骨骼性雙型是值得探討並詳細描述的題材。除此之外，本研究還將所觀察骨骼結構及側線鱗數等外部形態特徵，與紫錦魚 (Thalassoma purpureum)、三線紫胸魚 (Stethojulis trilineata)、雲斑海豬魚 (Halichoeres hortulanus)、黑鰭半裸魚 (Hemigymnus melapterus)、裂唇魚 (Labroides dimidiatus)、青斑阿南魚 (Anampses caeruleopunctatus)、紅喉盔魚 (Coris aygula) 與狹帶全裸鸚鯛 (Hologymnosus doliatus) 等八種近緣物種進行比較，並探討彼此間的親緣關系。本研究切除雜色尖嘴魚之肌肉與皮膚觀察骨骼色彩；使用軟硬骨二重染色法觀察骨骼形態，再以手繪圖及相片呈現觀察結果；親緣關係之探討建立利用NEXUS Data Editor 紀錄特徵狀態並製作特徵矩陣，最後以PAUP* 4.0建構親緣關係樹。結果顯示雜色尖嘴魚之尾鰭部位已確認為Randall (2005) 和Westneat (2001) 之描述最為正確，雌魚截形；雄魚隨成長由截形延長為絲狀或微凹，並發現尾鰭末端之鱗片分佈雌魚皆呈縱向線狀排列，雄魚部分個體縱向線狀排列部分縱向內凹狀排列；骨骼色彩無性雙型；胸鰭部位無性雙型；其餘骨骼部位亦無性雙型；以三十個形態特徵為基礎進行探討的近緣物種之親緣關係，外群的紅喉盔魚被併入內群中，若以其中二十七個形態特徵為基礎進行分析，所建構之親緣關係樹可將內群之物種區分為單系群，內群中又可區分為兩個單系群，其樹形與先前研究之分子親緣關係樹大致上吻合。
The family Labridae is the most abundant and colorful fish family in coral reef ecosystem. Most species of the Labridae are sequential hermaphroditism. In addition, their external morphology exhibit obvious sexual dimorphism. Gomposus varius is one of members with elongating snout that exhibits obvious sexual dimorphism, including color patterns and the shape of caudal fin. However, despite the extraordinary morphology, there is no study on the morphology to investigate sexual dimorphism in osteology to date. Previous study has shown that males of Sundadanio can make sound through flapping their distinctive skeleton structure on pectoral fin for courtship. Gomposus varius display similar behavior, but there is still no study on whether this species has distinctive skeleton structure on their pectoral fin or not. In addition, the descriptions on the shape of caudal fin are not congruent among different authors. Previous study has shown sexual dichronism present in other labrid fish. It is possible that sexual dichronism was also present in G. varius. The aim of the present study is to examine the sexual dimorphism in G. varius and to reconstruct the phylogeny of the genus Gomposus and related genera using morphological characters. Muscles of G. varius were removed and specimens of G. varius were cleared and stained to compare the color of bones and the structures of skeletons between male and female. There is no sexual dimorphism observed in color of skeleton and the morphology of pectoral fin. The remaining parts of skeleton did not exhibit sexual dimorphism either. However, the arrangement of last vertical-scale row might be sexual dimorphic. It is arranged in a straight line in females and small males and arranged in a “<” shape in larger males. Further study may be needed to confirm the correlation of the arrangement to sex. The shape of caudal fin described by Randall (2005) and Westneat (2001) is supported by the present study, caudal fin rounded in small individuals, but truncate with prolonged into filamentous in large males. In addition, twenty nine characters of skeleton and numbers of lateral-line scales of G. varius, Thalassoma purpureum, Stethojulis trilineata, Halichoeres hortulanus, Hemigymnus melapterus, Labroides dimidiatus, Anampses caeruleopunctatus, Coris aygul and Hologymnosus doliatus were examined. The character matrix was made by NEXUS Data Editor and the phylogenetic tree were reconstructed by PAUP* 4.0. In the phylogenetic tree reconstructed by all morphological characters, Coris aygul, a species considered as an outgroup, has been placed as a sister group of Halichoeres hortulanus. However, while three characters, thickness of circumorbital bone, shape of leading edge of hyomandibular, depression of lower edge of hyomandibular, were removed, the topology of the morphological tree is congruent with previously published molecular tree, with G. varius, T. purpureum, S. trilineata, H. hortulanus, Hemigymnus melapterus, L. dimidiatus, A. caeruleopunctatus divided into two groups and G. varius a sister group of T. purpureum.