Abstract:

The Jianhe Biota discovered in the“Tsinghsutung Formation”(Cambrian Stage 4) at Songshan (Jiugaoshan) Section near
Balang Village, Jianhe County, Guizhou Province consists of soft-bodied fossils with abundant trilobites. Olenoides Meek, 1877
(Dorypygidae, Trilobita), ranging from Cambrian Duyunian (Stage 4) to the late Cambrian Guzhangian (Stage 7), is an important fossil
for global stratigraphic correlation. This taxon from the“Tsinghsutung Formation”includes 2 species: Olenoides contrictus (Chien，
1961) andO. cf. hubeiensis (Sun, 1984) which are the primitive morphotypes of O. paraptus and O. hubeiensis that occurred in the
overlying Kaili Formation. The Olenoides from the“Tsinghsutung Formation”(lower Duyunian, Qiandongian, global Cambrian Series 2)
is known to be the lowermost occurrence for this genus. The discovery of Olenoides in the“Tsingsutung Formation”not only sheds new
light on the early morphology, evolution, and distribution of this group, but also provides new constraint for the biostratigraphic study of
Cambrian Stage 4 (Duyunian).

Key words: Olenoides;“Tsinghsutung Formation”, Duyunian, Cambrian, Guizhou Province