A new Moscovian foraminiferal fauna from Huai Luang, east of Wang Saphung, Changwat Loei, Northeast Thailand

Abstract

The unusual rarity of Fusulinella species is one of the most interesting characteristics among the known Moscovian foraminiferal faunas in Thailand. Earlier an occurrence of Fusulinella bocki von Möller was documented in Northeast Thailand but with neither description nor illustration. For the first time, we have recently discovered a small foraminiferal fauna characterized by two Fusulinella species ( F. bocki von Möller and F. praebocki Rauser-Chernoussova) from a limestone collected at Huai Luang, about 5 km east of Wang Saphung, Changwat Loei, Northeast Thailand, where the Fusulina pulchella fauna was reported previously. Geological evidence suggests that our foraminiferal fauna most certainly came from the strata referable to the Fusulina pulchella Zone although F. pulchella Gryzlova is absent from our fauna. The present discovery of a Fusulinella-bearing foraminiferal fauna from Huai Luang, indicative of a Late Moscovian age (most probably to the Myachkovsky Horizon in the Russian standard scheme), provides important data to clarify the faunal composition of the Fusulina pulchella Zone and to compare the Late Moscovian foraminiferal faunal affinity in the Loei-Wang Saphung area with those of the type and reference sections. In this paper, six species of fusulinaceans are described, and coexisting smaller foraminifers are listed and illustrated.