Satunarcus, a new late Cambrian trilobite genus from southernmost Thailand and a reevaluation of the subfamily Mansuyiinae Hupé, 1955

Abstract

The Ao Mo Lae Formation of the Tarutao Group crops out on Thailand's Tarutao Island and contains a diverse assemblage of late Furongian trilobite taxa, including several endemic forms. This study presents a new genus and species, Satunarcus molaensis, discovered at two locations on the island. A cladistic analysis of the kaolishaniid subfamily Mansuyiinae in light of Satunarcus and similar genera known from across upper Cambrian equatorial Gondwanan rocks suggests that the subfamily is polyphyletic in its current definition, and thus is not a natural group. Separating Mansuyia Sun, 1924 from the other taxa conventionally placed in Mansuyiinae permits recognition of a previously unrecognized monophyletic subfamily Ceronocarinae new subfamily. As established herein, this kaolishaniid subfamily contains Satunarcus n. gen. and all genera previously recognized as Mansuyiinae. with the exception of Mansuyia itself. Ceronocarinae n. subfam. occur in middle Jiangshanian to middle Cambrian Stage 10 sedimentary rocks from Australia, South China, North China, and Sibumasu, with most genera endemic to Australia. UUID: http://zoobank.org/618c5136-73f0-4912-a7d3-e56559d2a76c

Paleomagnetic insights into the Cambrian biogeographic conundrum: Did the North China craton link Laurentia and East Gondwana?

“…3). The newly formed tectono-paleogeographic archipelago could thus have provided young zircon grains to the sedimentary basins in the NCC and led to more extensive biological exchanges in the late Cambrian (Zhang, 2003;Álvaro et al, 2013;Collette, 2014;Wernette et al, 2020). Further phylogenetic and paleobiogeographic analyses are necessary to test this hypothesis.…”

“…520 Ma; Dalziel, 2014). However, it is puzzling that as the Iapetus Ocean widened, the late Cambrian witnessed more common biogeographic features between Laurentia and Gondwana (Álvaro et al, 2013;Collette, 2014;Wernette et al, 2020). Interesting questions are when and how the trilobites in different realms began to communicate with each other.…”

“…Interesting questions are when and how the trilobites in different realms began to communicate with each other. The North China craton (NCC) has long been considered to have a close biogeographic association with East Gondwana because it yields the typical redlichiid trilobites (e.g., Zhang, 2003), but recent discoveries of a few characteristic fossils of Laurentia in Wuliuan shales in the eastern NCC (Sun et al, 2020a(Sun et al, , 2020b, together with the mixture of middle and late Cambrian trilobites among the NCC, East Gondwana, and Laurentia (e.g., Zhang, 2003;Álvaro et al, 2013;Collette, 2014;Wernette et al, 2020), prompt us to investigate the role of the NCC in biogeographic changes between East Gondwana and Laurentia in the middle to late Cambrian.…”

Trilobites of Thailand's Cambrian–Ordovician Tarutao Group and their geological setting

“…Three of the endemic species are from monospecific endemic genera: Tarutaoia , Thailandium and Satunarcus (see also Wernette et al . 2020a, 2020b). New material of every trilobite species or form illustrated in previous studies was recovered in our work, possibly excluding one indeterminate leiostegiid (Shergold et al .…”

Paleogeographic Reconstruction of the Paleozoic Lhasa Terrane Through Detrital Zircon Mixing Modeling

“…It is generally accepted that the strata in the Lhasa, and Southern Qiangtang terranes, and Greater India record a marked Cambrian–Ordovician angular unconformity (cf., Myrow et al., 2010; Hu et al., 2021), suggesting the paleogeographic links between them. In contrast, the Sibumasu terrane strongly resembles NW Australia (i.e., the Canning basin) in the lowermost Ordovician stratigraphic succession from clastics to carbonates, and in the latest Cambrian sedimentary succession and shared elements of its trilobite fauna (Wernette et al., 2020a, 2020b, 2021). This history allies Sibumasu and NW Australia at this time, but the status of the Baoshan terrane, commonly considered part of Sibumasu, remains to be clarified.…”