Taxonomy

Phylum: ？Rhodophyta

Class: uncertain

Order：uncertain

Family: uncertain

Genus：Qingjiangthallus gen. nov.

Specie: Qingjiangthallus cystocarpium sp. nov.

Description: Fronds consist of branched or unbranched thalli with a holdfast. Thalli branch sparsely or profusely in three different patterns, i.e., 1–3 times asymmetrically, 1–2 times dichotomously, and laterally branched patterns. Branching angles vary from 20° to 98°. Branches are flat, ribbon-shaped, without stipe, usually curved slightly upwards and sharpened at the tips. They vary from 1.2 mm to 4.0 mm in width, and are up to 10.4 cm tall. For asymmetrically and laterally branched thalli, the main branches are always curved and slightly wider than other branches. Some have one or more proliferous branchlets, which are 1.4–3.7 cm long and usually in the lower portion of thalli. Lateral branches grew upwards away from the insertion point, and are regularly arranged in the upper portion of thalli. For dichotomously branched thalli, all branches have almost the same width. Holdfasts are discoid or globose in shape, 2.4–4.2 mm in diameter, without rhizoids or any other appendage, and each bears one or two branches.

Dense dark spots are present on the surface of the whole thallus and numerous on most branches. Their density increases towards the tip of each branch, where they closely contact each other. Dark spots are elliptical to circular in outline, and show a moderate relief. They are variable in size, the major axis ranges from 246 μm to 838 μm, and the minor axis ranges from 189 μm to 653 μm.

Age & Localities

Age: Cambrian Series 2, Stage 3

Principal localities: The middle member of the Shuijingtuo Formation in the Jinyangkou Section, Changyang County, Hubei Province, China.