Paper No. 71-1
Presentation Time: 8:05 AM
THE FIRST REPORT OF THE RADIODONTAN CARYOSYNTRIPS FROM THE EARLY CAMBRIAN (SERIES 2, STAGE 3) MALONG BIOTA OF SOUTH CHINA
YANG, Xianfeng, Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University,, Kunming, Yunan Province, China; MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology,Yunnan University, Kunming, Yunan Province 650091, China, JULIEN, Kimmig, Paläontologie und Evolutionsforschung, Abteilung Geowissenschaften, Staatliches Museum für Naturkunde Karlsruhe, Karlsruhe, 76133, Germany; The Harold Hamm School of Geology & Geological Engineering, University of North Dakota, Grand Forks, ND 58202, USA, Grand Forks, ND 58202, PATES, Stephen, Department of Zoology, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom and MA, Shuhan, Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University,, Kunming, Yunan Province, China; MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, Yunan Province 650091, China
Radiodontans are well-known, diverse members of Burgess Shale-type Lagerstätten. Many species are considered apex predators from the Cambrian Series 2 to the Ordovician, with some even persisting into the Lower Devonian. Complete radiodontan specimens are exceedingly rare, with the majority of fossils representing isolated appendages. They are classified into four families, namely the Anomalocarididae, Amplectobeluidae, Tamisiocarididae, and Hurdiidae. Caryosyntrips serratus, which holds an uncertain phylogenetic position, was initially described from the Burgess Shale of Canada. More recently, additional species have been described; Caryosyntrips camurus, Caryosyntrips durus, and Caryosyntrips cf. camurus, which have also extended the range of the genus in Laurentia.
In this study, we present the first occurrence of Caryosyntrips cf. serratus from the lower Cambrian Malong biota of South China. This biota is slightly younger than the Chengjiang biota, but also preserves exquisite 2D compression fossils. The presence of the index polymerid trilobite, Malungia laevigata Lu, 1961, indicates that the stratigraphic interval yielding the specimen belongs to the upper part of the Hongjiangshao Formation, equivalent to the unnamed Cambrian Series 2, Stage 3 within the global chronostratigraphic framework.
The new material is preserved as part and counterpart, measuring approximately 35mm in length and bearing 14 podomeres. Its outline is elongated and tapering, with straight ventral and dorsal surfaces. The angle between the outer and inner edges of the appendages is 25°. A pair of triangular ventral spines extends from the ventral surface of each podomere, while a row of smaller dorsal spines can be observed along the outermost edge of the dorsal surface, spaced approximately 1mm apart. Podomere membranes are faint but clearly visible on the ventral surface.
The discovery of this new material represents the first occurrence of this genus in China, significantly enhancing our understanding of its evolutionary history. These findings not only contribute to the diversity data of radiodontans in Gondwana but also suggest an earlier origin for this taxon than previously thought.
![[Visit Client Website]](/img/gsa/banner.jpg)