Jiao De-Guang, Pates Stephen, Lerosey-Aubril Rudy, Ortega-Hernández Javier, Yang Jie, Lan Tian, Zhang Xi-Guang
Yuxi Normal University, Kunming, 134 Phoenix Road, Yuxi, Yunnan 653100, People's Republic of China.
Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, People's Republic of China.
R Soc Open Sci. 2021 Nov 10;8(11):211134. doi: 10.1098/rsos.211134. eCollection 2021 Nov.
Stem-group euarthropods are important for understanding the early evolutionary and ecological history of the most species-rich animal phylum on Earth. Of particular interest are fossil taxa that occupy a phylogenetic position immediately crownwards of radiodonts, for this part of the euarthropod tree is associated with the appearance of several morphological features that characterize extant members of the group. Here, we report two new euarthropods from the Cambrian Stage 4 Guanshan Biota of South China. The fuxianhuiid ? sp. is represented by isolated appendages composed of a gnathobasic protopodite and an endite-bearing endopod of at least 20 podomeres. This material represents the youngest occurrence of the family Chengjiangocarididae, and its first record outside the Chengjiang and Xiaoshiba biotas. We also describe gen. et sp. nov. based on well-preserved and robust isolated appendages. exhibits an atypical combination of characters including an enlarged rectangular base, 11 endite-bearing podomeres and a hypertrophied distal element bearing 8-10 curved spines. ? sp. appendages display adaptations for macrophagy. appendages resemble the frontal appendages of radiodonts, as well as the post-oral endopods of chengjiangocaridid fuxianhuids and other deuteropods with well-documented raptorial/predatory habits. contributes towards the record of endemic biodiversity in the Guanshan Biota.
干群真节肢动物对于理解地球上物种最为丰富的动物门类的早期进化和生态历史至关重要。特别令人感兴趣的是那些在系统发育位置上紧挨着放射齿类位于冠部方向的化石类群，因为真节肢动物谱系的这一部分与一些表征该类群现存成员的形态特征的出现相关联。在此，我们报道了来自中国南方寒武纪第4期关山生物群的两种新的真节肢动物。抚仙湖虫科未定种由孤立的附肢代表，这些附肢由一个具颚基的原肢节和一个至少有20个肢节且带有内叶的内肢组成。该材料代表了澄江虾科最年轻的化石记录，也是其在澄江生物群和小石坝生物群之外的首次记录。我们还基于保存完好且粗壮的孤立附肢描述了新属新种。该新属新种展现出一系列非典型的特征组合，包括一个扩大的矩形基部、11个带内叶的肢节以及一个带有8 - 10根弯曲刺的肥大远端部分。未定种的附肢显示出对大型食性的适应性。该新属新种的附肢类似于放射齿类的额附肢，以及澄江虾科抚仙湖虫类和其他具有明确抓捕/捕食习性的双肢节动物的口后内肢。这一新属新种丰富了关山生物群的特有生物多样性记录。
