Macroalgal fossil Longfengshania from the Tonian Shiwangzhuang and Jiuliqiao formations in western Shandong and northern Anhui, North China

Abstract

Longfengshania is among the few examples of Pre-Cryogenian macroscopic fossils with an unambiguous eukaryotic affinity. It has received great attention since this genus is the earliest known Pre-Cryogenian macroalga with blade, stipe, and holdfast differentiation. However, compared to other macrofossils, such as Chuaria and Tawuia, reported occurrences (lithostratigraphic units) of Longfengshania are limited in Tonian strata, restricting the assessment of paleogeographic distribution of Longfengshania and therefore hindering our understanding of its paleoecological role in the Tonian oceans. Here, we describe two new localities of Longfengshania, including the Tonian Shiwangzhuang Formation (∼850–720 Ma) in western Shandong and Jiuliqiao Formation (∼950–720 Ma) in northern Anhui, North China. Specimens of Longfengshania from the Shiwangzhuang and Jiuliqiao formations are smaller than specimens from other localities, which has been interpreted as adaptations to relatively stronger hydrodynamic conditions. Biometric and principal component analyses suggest that most other species of Longfengshania actually fall within the morphospace range of the type species L. stipitata and therefore a re-examination on previously reported specimens and a taxonomic revision for this genus are needed in future study.