The Relative Distribution of Otoliths as a Means of Larval Fish Identification

以耳石的相對位置當作仔魚鑑定的形質

陳麗淑(Li-Shu Chen) ； 嚴宏洋(Hong-Young Yan)

《Zoological Studies》 41卷2期 (2002/04) Pp. 144-152

摘要

最近發展的聽覺腦幹反應（ABR）技術指出，魚類聽覺引發的腦波具有種的特異性。這些腦波反映聽覺核和沿著往上的聽覺神經通路的空間分布。從腦波的種特異性可以引申出耳石的分布應該也是具有種特異性的假說，因為耳石由面所在的感覺毛激發的反應引發ABR第一個波。本研究從臺灣和美國德州採用八種仔魚（分屬於四科八屬），以胰蛋白酵素將魚體處理成透明，再用解剖顯微鏡裝置偏光鏡觀察。三個參數（囊狀石間距inter-utricular ratio, IUR；矢狀（扁平）石間距inter-saccular ratio, ISR；星狀石間距inter-lagena ratio, ILR）用來度量耳石間距和眼距的比例。IUR和ISR可以成功地把種分開，但ILR因為星石發育較晚就顯不出作用。本研究結果支持原先所提的假說：仔魚耳石的空間分布可以當成一個有效的形質來分離不同的種。

關鍵字

機械式感覺生理學 ； 內耳 ； 耳石 ； 聽覺路徑 ； 分類

並列摘要

A recently developed auditory brainstem response (ABR) protocol has indicated that acoustically evoked brainwaves in fishes are species-specific. These brainwaves reflect the spatial distribution of auditory nuclei and the 3 auditory end organs along the ascending auditory neuronal pathways. Species-specific brainwaves suggest the hypothesis that the distribution of otoliths, which are closely coupled with sensory hair cells whose evoked response forms the 1st wave of the ABR, should also be species-specific. Eight species of marine fish larvae (belonging to 8 genera and 4 families) collected from Taiwan and Texas, USA were cleared in trypsin and examined microscopically with double polarization filters. Three indices (inter-utricular ratio, IUR; inter-saccular ratio, ISR; and inter-lagena ratio, ILR) were developed to measure the ratio of inter-otolithic to inter-orbital distances. IUR and ISR succeeded in separating species, but ILR was not as useful because of late development of the lagena. This study supports the hypothesis that the distribution of otoliths in fish larvae differs among species.

並列關鍵字

Mechanosensory physiology ； Inner ear ； Otolith ； Auditory pathway ； Taxonomy