Taxonomical and Paleoenvironmental Study of Genus MELONIS (Benthec Foraminifera)

火腿属是一个钙质底栖有孔虫属，被认为是第四纪至今深海底水的标志，从分类学和古生态角度对该属的分类和种内变异进行了研究。根据采集自四国海域、大藤岭附近、小川群岛以东和沙茨基隆起附近的四个活塞芯的标本，对该属的分类和种内变异进行了生物计量学研究。在分类比较中使用了几种参考材料。它们是来自赤道太平洋和鄂霍次克海以及包括地中海地区在内的一些参照区的少量月形沉积物。A和M.barleeanus是在晚更新世至全新世的活塞芯序列中发现的。该属的膨大形式有别于地中海地区典型的蓬利氏支原体。甜瓜含有一种冷水变种，在两个较浅的地点都有发现。本变种生活在鄂霍次克海。蜜瓜，以非常细微的穿孔壁为特征，只在两个较深的地方发现，蜜瓜在软化壁的程度上有较大的差异，形状(典型的巴利安蜜瓜到多足的一个尼古巴拉型)。后者已被一些作者鉴定为帕氏支原体。为了了解化石物种的分布，人们收集了大量的标本。此时此刻，在北海道至冲绳的上始新世至下更新世已发现蜜瓜标本。这些分类研究是持续进行的。

The genus Melonis, which is a calcareous benthic foraminiferal genus and regarded as an indication of deep-sea bottom water in the Quaternary to Recent, is exmained taxonomically and paleoecologically.The taxonomy and intraspecific variations of the genus in the Northwest Pacifec are biometrically examined based on the specimens from four piston-cores collected from off Shikoku, near the Daito Ridge, east of Ogasawara Islands and near the Shatsky Rise. Several reference materials are used for the taxonomic comparison. They are a few rescent sediments from the equatorial Pacific Ocean and Okhotsk Sea and some reference areas including the Mediterranean region.As a result, Melonis sphaeroides, M. affinis, M. SP. A and M. barleeanus are identified in the late Pleistocene to Holocene sequences of the Piston-cores. The inflated form of the genus is distinguished from the typical M. pompilioides in the Mediterranean region. Melonissphaeroides contains a cold -water variety, which is found in the two shallower sites. This variety is living in the Okhotsk Sea.Melonis affinis, characterized by very finely perforated wall, is found only in the two deeper sites Melonis barleeannus has wider variation on the degree of limbate wall, form (typical M. barleeanus to much limbate one M. nicobarensis-form). The latter form has been identified as M. parkerae by some authors.A lot of samples have been collected to recognize distribution of fossil species. In this moment, specimens of Melonis have been found in the upper Eocene to lower Pleistocene from Hokkaido to Okinawa. Those taxonomic study is performed continuously.