硬骨魚類耳石的形態學研究主要是藉其物種辨識能力,應用在族群管理、魚類掠食者的食性分析,以及重建古魚類等。本研究從建立台灣東北部海域魚類耳石形態資料庫著手,以鑑定古魚類的化石耳石並重建古環境為最終目標。現生魚類標本的採集地點主要為宜蘭縣大溪漁港,自2008年10月到2010年1月間,每兩週採集標本一次。將魚體標本帶回研究室內,予以分類、測量、照像、比對。並將魚類三對耳石中的矢狀石(sagitta)取出,進行分類、測量、照像、比對、繪圖與分析的研究。本研究所蒐集的魚類耳石標本共有230個物種,分屬於23目、100科、176屬。分析結果顯示,科以上的魚類分類階層可以用耳石外部形態與大小測量做簡易區分,並針對耳石標本製作了檢索表。化石耳石標本則採自台北縣樹林市,中新世晚期到上新世早期的桂竹林層(約五百萬年前),該地層因鄰大漢溪長期切蝕而出露。化石耳石標本有石首魚科(Sciaenidae)中黃魚屬的大黃魚(Larimichthys crocea)及小黃魚(Larimichthys polyactis)、大頭白姑魚(Pennahia macrocephalus)、黃姑魚屬的黃姑魚(Nibea albiflora)與半斑黃姑魚(Nibea semifasciata)以及瞻星魚科(Uranoscopidae)的鰧屬(Uranoscopus)魚類,其中以底棲性魚類的黃魚屬最多。參照現生魚種的生態後,可以推測化石耳石所屬的古魚類生活的古環境屬於近沿岸、相對水流較平緩,大陸棚區內,富含砂泥底質的溫帶至亞熱帶海域。
Morphology of fossil otoliths can be used for identification and thus can be used to reconstruct paleoenvironments. Lots of fossil otoliths have been found in Taiwan without identifications. However, studies of otolith morphology of extant fishes are rare in Taiwan. It is necessary to survey a large scale of local fish species with related otoliths prior to fossil otoliths analysis. The purpose of this study is to construct a otolith morphology database of living fishes, which can help collate with fossil otoliths, and finally, to reconstruct a possible paleoenvironment. Living fishes from Da-si fishing port have been collected from October 2008 to January 2010. The fish samples represent 23 orders, 100 families, and totally 230 species. Left sagitta are figured by stereomicroscope. The shapes of sagitta can be as a key to identify the fish at family level. Aspect ratio is also included in shape analysis, which is helpful in distinguishing more related species. Demersal taxa indicate sagitta with larger otolith length, whereas those living in the deep-sea ocean have the smaller otolith length. Fossil teleostean otolith from Shulin, Taipei county, northern Taiwan was described for the first time. The outcrop was recovered along the Tahan river bank. Samples were collected from the Late Miocene to Early Pliocene Kueichulin Formation. Morphology comparison of the fossil otoliths with living ones showed that most of them belonged to family Sciaenidae. They were Larimichthys crocea, Larimichthys polyactis, Pennahia macrocephalus, Nibea albiflora and Nibea semifasciata. One specimen from Uranoscopidae, genus Uranoscopus was also included. All of the characteristics were drawn. Identifications of these fossil otoliths leaded us to conclude that the paleoenvironment of sample site was near shore marine with sand to sandy mud bottom, and temperate to subtropical condition.