Furongian (Jiangshanian) occurrences of radiodonts in Poland and South China and the fossil record of the Hurdiidae

Abstract

The Furongian period represents an important gap in the fossil record of most groups of non-biomineralizing organisms, owing to a scarcity of Konservat-Lagerstätten of that age. The most significant of these deposits, the Jiangshanian strata of the Sandu Formation near Guole Township (Guangxi, South China), have yielded a moderately abundant, but taxonomically diverse soft-bodied fossil assemblage, which provides rare insights into the evolution of marine life at that time. In this contribution, we report the first discovery of a radiodont fossil from the Guole Konservat-Lagerstätte. The specimen is an incomplete frontal appendage of a possibly new representative of the family Hurdiidae. It is tentatively interpreted as composed of seven podomeres, six of which bearing laminiform endites. The best preserved of these endites is especially long, and it bears short auxiliary spines that greatly vary in size. This is the second occurrence of hurdiids and more generally radiodonts in the Furongian, the first being the external mould of an oral cone from Jiangshanian strata of the Wiśniówka Sandstone Formation in Poland. Restudy of this Polish specimen confirms that it belongs to a hurdiid radiodont and best compares to Peytoia. The family Hurdiidae includes the oldest (basal Cambrian Epoch 2) and youngest (Early Ordovician, possibly Early Devonian) representatives of the Radiodonta and as such, has the longest stratigraphical range of the group. Yet, hurdiids only became prominent components of marine ecosystems during the middle Cambrian (Miaolingian), and their fossil record in younger strata remains limited.

A large pelagic lobopodian from the Cambrian Pioche Shale of Nevada

“…In Ramskoeldia platyacantha Cong et al, 2018 and a number of isolated body flaps from the Emu Bay Shale (Daley et al, 2013), the flaps are broad and roughly triangular, with a posterior margin essentially perpendicular to the trunk axis, with a wide anterior zone ornamented with strongly anterodistally directed strengthening rays. This occasionally leads to their confusion with the body flaps of peytoiids (Zhu et al, 2021). In peytoiids, flaps are generally short, either subcircular or triangular, and may be paired with dorsal flaps (Van Roy et al, 2015).…”

New soft-bodied panarthropods from diverse Spence Shale (Cambrian; Miaolingian; Wuliuan) depositional environments

“…Classification and terminology herein followed Kimmig and Pratt (2015), Lerosey-Aubril and Pates (2018), Lerosey-Aubril et al (2020a, b), Pates et al (2021a), Wu et al (2021a, b), and Zhu et al (2021).…”

The significance of Anomalocaris and other Radiodonta for understanding paleoecology and evolution during the Cambrian explosion

“…The last Drumian localities are the Jince Formation and the Buchava Formation (Czech, Gondwana) with Hurdia (Chlupáč and Kordule, 2002;Mikuláš et al, 2012;Daley et al, 2013a;Wu et al, 2022). The only two hurdiids found in the Furongian, and the last of the Cambrian hurdiids, are from the Sandu Formation (Jiangshanian-South China) with an undetermined hurdiid and the Wiśniówka Formation (Jiangshanian-Baltica) with a Peytoia (Zhu et al, 2021;Wu et al, 2022). In the Ordovician, there is the Afon Gam (Tremadocian-Avalonia) that has a hurdiid specimen (Pates et al, 2020;Wu et al, 2022).…”

“…Hurdiidae are the most geographically widespread, being the only family found in the North China domain so far (Sun et al, 2020a;Wu et al, 2022). It is also the only family that lived in higher latitudes, in Baltica at a bit more than 30 °, and in Czech at around 60 °, during the Cambrian (Chlupáč and Kordule, 2002;Mikuláš et al, 2012;Zhu et al, 2021;Wu et al, 2022). During the Lower Ordovician, there were only hurdiids found, with fossils collected from high paleolatitudes of the southern hemisphere under the 60 °S latitude in the north margin of Gondwana and the south of Avalonia, both surrounding the Rheic ocean that was opening at that time (Van Roy et al, 2015;Pates et al, 2020;Zhu et al, 2021;Wu et al, 2022).…”