Curviacus

The genus name Curviacus references the shape of the crescent chambers; coming from Latin curvus meaning curved and acus meaning needle.[1]

The phylogeny of this fossil is not yet known. Some scientists believe the genus to be a coralline algal or fungal stem group.[1]

C. ediacaranus is from the late ediacaran. The fossil C. ediacaranus has been found in the Shibantan member of the Denying Formation.[1] The Sibantan member is the bituminous limestone section of the formation.[2] It is unusual for ediacaran biota to be preserved in limestone. As such, C. ediacaranus is the only Palaeopascichnus fossil to be reported from carbonate rock rather than siliclastic rock. [1] This special type of fossilization allows for 3 dimensional analysis. [1]

These fossils occur on bituminous limestone on the bedding surface. The fossilized specimen has calcispar walls with the inner chambers filled with micrite. [1] The walls are raised because the calcispar does not erode as easily. C. ediacaranus is a slightly oblong macrofossil that ranges from 5-14 cm in length. It is charichtaridzed by its curved or crescent shaped chambers that occur arranged in a series with the chambers sharing walls. All of the chambers are convex in the same direction. Each chamber is narrow ranging ~1-3mm in width. [1] Chamber length can be consistent or inconsistent. Inconsistencies can give a false impression of branching. [1] Additionally, the walls of the chambers sometimes converge laterally.