The Heishapo section at Zhongnan Village is located 6 km southwest of Songlin Town, and about 26 km east of Zunyi City (Fig. 1). Roadcuts making up the section are easily accessible by automobile. The section, which yields a moderately diverse Cambrian biota, was initially discovered by the Sino-German collaboration team in April 1998. The early Cambrian fossils recovered from the section were originally referred to as the Niutitang Biota (Zhao et al., 1999). Concentrated collecting effort since 1998, however, has resulted in recognition of rather distinct fossil assemblages in the lower-middle and upper parts of the Niutitang Formation (Fig. 2). As a result, the Niutitang Biota has been subdivided into the Songlin Biota (Zhao et al., 1999), which occurs in the lower and middle parts of the Niutitang Formation, and the Zunyi Biota, which occurs in the upper part of the formation (Steiner et al., 2001, 2005). In this paper, the two faunal assemblages are simply referred to as the upper and the lower Niutitang biotas. The upper biota (also known as the Zunyi Biota) is dominated by arthropod remains, and is reminiscent of the Chengjiang Biota in terms of its general faunal content. However, the lower biota (also known as the Songlin Biota) is dominated by sponges (Steiner et al., 2001; Zhao et al., 2002), and possibly represents a deeper water habitat. The Niutitang Biotia is similar to other Burgess Shale-type biotas both in biotic composition and taphonomic overprint. Paleontological description of the Niutitang Biota has been proceeding swiftly since 1999 (Yang and Zhao 2000; Yang et al., 2003, 2005; Peng et al., 2004, 2005; Wang et al., 2005).
展开▼
