臺灣西南部新化丘陵地區齧齒動物化石牙齒之研究

• Main Authors: 茅秀娟, Mao, Xiu-Juan
• Other Authors: 地球科學系, 鍾廣吉;吳銘志, Chung, Kuang-Jyi;Wu, Ming-Chee
• Format: Thesis
• Language: Chinese
• Published: 2003
• Subjects: 古生態環境;微細構造;新化丘陵;齧齒動物; paleo-ecological environment;microstructure;rodent;Shin-Hua Hill; Rattus rattus
• Online Access: http://ir.lib.ncku.edu.tw/handle/987654321/213218; http://ir.lib.ncku.edu.tw/bitstream/987654321/213218/1/index.html

齧齒動物之生存期限短、繁殖快、數量多、分佈廣，因此特別可用於指示當時的生態條件。但也由於齧齒動物的動作非常敏捷，又常是肉食性動物的食物來源之一，因而能保存成化石的機率非常低，若要利用大量化石作為鑑種的方法似乎是不容易的。 本研究利用標本量測值之L/M與pi/pe及其他微細構造形態特徵以協助鑑種，發現於新化丘陵區出露之齧齒動物化石計有褐鼠、刺鼠、玄鼠及鬼鼠，其生存環境為低海拔區的森林、草生地或河邊。 本文研究的齧齒動物化石大部分出露自二重溪層，且伴隨著齧齒動物化石出現的還有古生態條件為陸相森林環境的其他生物群落，故推測新化丘陵區二重溪層當時的古生態環境為低海拔區靠近海陸交界處的森林環境，當動物死亡後在較快的時間與較短的距離即被河流搬運至海岸淺海區停積。 Rodents are mammals with short lifespan, high reproduction rates, vast populations, and widespread geographic distributions; thus making them the prime target for use as indicators of paleo-ecological environments. However, due to the active life cycle of rodents and their status as the bottom feeders in the food web, it is rather difficult to find well-preserved specimens of rodent fossils. This study utilizes measurements of L/M, ratios of major and short axes from masticating area, with pi/pe, ratios of inner and outer enamel thickness, and characteristics of some other microstructures to identify the rodent fossils. The results indicate that in the study area, Shin-Hua Hill, four different species of rodents, Rattus norvegicus、Niviventer coxingi、Rattus rattus、Bandicota indica, were found. Their habitats include open grasslands, scrub forests, marshes and river banks. The rodent fossils collected in this study were mainly scattered in the Erchungchi Formation. Besides rodent fossils, other mammalian fossils commonly associated with continental forest environments were also found nearby. Consequently, habitat around Shin-Hua Hill area was regarded to be low-altitude forest close to beach area. Remains of animals were rapidly flashed out by rivers, and deposited in the shallow water coastal regions and delta plains where fossils from the Erchungchi Formation were found.