臺灣西南部嘉義牛埔地區常見的早更新世魚類耳石

魚類耳石形態學長久以來被應用於古魚類系統分類、生物地層、古生物地理等研究上。在臺灣，儘管一些已知的上新世及更新世海洋地層富有魚類耳石化石，卻從未有系統性的研究報告。本研究首次描述了臺灣西南部嘉義縣八掌溪旁之早更新世六重溪層中，由業餘化石收集者採自沉積物表面的化石耳石，經比對國立海洋生物博物館典藏之現生魚類耳石標本，分類鑑定以重建古魚類群聚構造。石首魚科和天竺鯛科的耳石是最常見的分類群；其中小黃魚耳石的出現表明其於早更新世的分布較現今更為普遍。本研究提供臺灣西南部相關地層中常見大型耳石的識別指南，提升本地古生物學的研究，並作為未來相關研究工作的開端。

關鍵字

古魚類；六重溪層；小黃魚；分類學；古生物地理

並列摘要

Fossil otolith assemblages have been reported from many regions of the world to interpret regional paleoecology and to reconstruct paleobiogeography. Studies from the western Pacific region, however, remain scarce. Despite a few known Plio-Pleistocene localities yielding fossil otoliths, a systematic study on such fossil assemblages has never been carried out in Taiwan. Common otoliths of early Pleistocene Liuchungchi Formation (1.22-1.95 Ma) along Bazhang River from Niubu in Chiayi County, southwestern Taiwan were described for the first time. Otoliths were collected from the surface of sediments by amateur fossil collectors. The recent otolith collection of Taiwan, deposited at the National Museum of Marine Biology and Aquarium, allows a well-comparable identification of fossil otoliths with great confidence. The otoliths of Sciaenidae and Apogonidae were the commonest taxa. The occurrence of Larimichthys polyactis otoliths indicates a more pervasive distribution of the fish than it is today. This paper is intended as a guide to the recognition of common large otoliths in the field, and the emphasis is firmly on promoting local paleontological work. A more detailed systematic description together with other localities will be dealt with in the forthcoming research.