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A well-preserved radiolarian assemblage is described from argillaceous limestone of the Wulalike Formation in the Northwest Ordos Basin, North China. A total of nine species of seven genera are described, including Inanigutta gansuensis, I. quadrispinosa, I. complanata, Inanibigutta pinglianensis, Oriundogutta bella, Triplococcus acanthicus, Haplentactinia juncta, Syntagentactinia pupila n. sp., and Kalimnasphaera maculosa. Three-dimensional X-ray micro-computed tomography is used to make a detailed examination of the new species. This is the first documentation of radiolarian fossils from the Wulalike Formation, which contributes to better understanding of the features of Ordovician radiolarian faunas and facilitate stratigraphic correlation and subdivision in the Ordos Basin.

We describe aggregative microconchid tubes from Middle-Late Triassic lacustrine strata of the Tanzhuang Formation in the Jiyuan-Yima Basin, North China. These microconchid tubes are attached to plant fragments and are preserved with bivalves, ostracodes, phyllostachys, gastropods, and coleoptera fragments. The findings confirm that the extinct lophophorate group inhabited non-marine continental basins. Microconchids dispersed extensively in continental basins and became common in lacustrine strata during Middle-Late Triassic. Its expansion may have been promoted by the recovery of the land ecosystem in the aftermath of the end-Permian crisis.

We studied a collection of the Silurian (Rhuddanian) multi-branched dendroids, including reticulate, benthic dendroid graptolites of the Callograptidae Hopkinson (in Hopkinson and Lapworth, 1875), from the Gorny Altai, Russia. Species of Dictyonema Hall, Koremagraptus Bulman, Callograptus Hall, and Desmograptus Hopkinson were identified and described. The graptolites are represented by in situ burial of colonies with 3D preservation of tubaria (= rhabdosomes). Complete (intact) colonies of dendroid graptolites are characterized by successive development stages: juvenile, neanic, ephebic (adults), while the general configuration of the tubarium changed from the proximal to distal. In a number of cases, later stage of colony development — the gerontic stage (senilis) is found. We carried out morphological analysis of dendroid graptolite tubaria (Callograptidae) of various development stages, showing eight morphotypes of the colonies, namely, the cylinder, disc, disc on a stem, hemisphere, cone, wineglass, blooming flower, and funnel type.

The mid-Carboniferous represents a key transition in the evolution of rugose corals, but the evolutionary pattern has been scarcely studied due to the lack of consecutive carbonate succession caused by Hercynian orogeny and Gondwana glaciation. In this study, seventeen rugose coral species belonging to fourteen genera are described from the late Visean to Bashkirian strata in the Suguersu section, northern Xinjiang, Northwest China. The late Visean is distinguished by large dissepimented solitary coral species, such as Haplolasma sp., Palaeosmilia murchisoni, and colonial coral Lithostrotion decipiens. Coral diversity dramatically decreased during the Serpukhovian, with only one species present. During the Bashkirian, rugose corals gradually recovered with the increased diversity and abundance, as evidenced by the occurrence of colonial coral Petalaxis kitakamiensis. This evolutionary pattern is consistent with that from South China and Russia, represented by the replacement of the Mississippian large solitary corals by the Pennsylvanian colonial corals. The Suguersu coral assemblage is composed of endemic taxa in Xinjiang and Qinghai regions of Northwest China, South China and Japan in northeastern Palaeotethys, as well as a few cosmopolitan elements across the Palaeotethys. This suggests that the Suguersu coral assemblage is biogeographically endemic, with occasional exchanges with other palaeo-oceans during the mid-Carboniferous period.

During the Ediacaran–Cambrian boundary interval, the Iberian margin of West Gondwana recorded oceanic upwelling and phosphogenesis favouring the preservation of originally phosphatic and diagenetically phosphatized shells. In the Abenójar Dome and the Alcudia Anticline of the Central Iberian Zone, the Fuentepizarra Formation comprises several phosphorite and phosphatic limestone interbeds that yield a microfossil assemblage rich in the helcionellid Anabarella plana, the halkieriid Halkieria sacciformis, the hyolith Conotheca subcurvata and chancelloriid debris. The assemblage is correlatable with the Purella antiqua Zone of the Aldan-Lena region and the Purella cristata Zone of the Anabar Uplift (Siberian Platform), slightly predating the Watsonella Zone of the Siberian Platform and the Watsonella crosbyi–Oelandiella korobkovi Zone of the northern Montagne Noire (France), both close to the (not yet globally defined) base of Cambrian Age 2. Despite the intra-Terreneuvian collapse of the Cadomian Orogen, stratigraphically associated with the onset of diachronous gaps, the base and top of the Fortunian Stage is well constrained throughout southwestern Europe based on radiometric ages and the micro- and ichnofossil record.

The Lochkovian and Pragian (Lower Devonian) in the South China Block are mainly represented by siliciclastic rocks that were deposited soon after the end of the Kwangsian Orogeny during the Silurian–Devonian transition. The Pragian conodonts in the South China Block have been poorly documented, and the Lochkovian/Pragian boundary, defined by the first appearance of the conodont Eognathodus irregularis, has never been successfully demonstrated. The present study provides new evidence by restudying conodonts from the Gaoling Member of the Nahkaoling Formation at the Lingli section, central Guangxi. In addition to the previously reported Zieglerodina? tuojiangensis Lu in Lu et al., Pandorinellina exigua lingliensis Lu in Lu et al., and Pandorinellina exigua exigua (Philip) by Lu et al. (2023), the conodont record is expanded to include Pseudooneotodus beckmanni (Bischoff and Sannemann), E. irregularis (Druce), E. grandis n. sp., and Eognathodus sp. A. With the lowest occurrence of E. irregularis in sample 21LL-21, the Lochkovian/Pragian boundary at the Lingli section is located at a level approximately 17.29 m above the base of the Nahkaoling Formation. This is for the first time that the Lochkovian/Pragian boundary is precisely documented in the South China Block. Above this level the strata from sample 21LL-21 to sample 21LL-46 can be correlated with the lower Pragian irregularis-profunda Zone. Moreover, the appearance of the newly described species, E. grandis n. sp., from the irregularis-profunda Zone in the Nanning-Liujing district suggests that the development of a well-arranged median longitudinal row of nodes, previously treated as the most important morphological change in the evolution from Eognathodus Philip to Polygnathus Hinde during the middle Pragian, in fact, can be dated back much earlier to the early Pragian. Accordingly, the derivation of Polygnathus from Eognathodus during the Pragian needs further investigation.

Sinacanthids are a group of Silurian spine-based mysterious taxa, probably representing a lineage of stem chondrichthyans. New sinacanthid fossils attributed to Sinacanthus wuchangensis, S. triangulatus, Sinacanthus sp., Neosinacanthus planispinatus, Tarimacanthus bachuensis, Eosinacanthus shanmenensis, and fin spine morphology 1, 2 and 3 are identified from the upper member of the Qingshui Formation and the Fentou Formation (Telychian, Llandovery) of Wuhan, South China. These sinacanthid fin spines are similar to those from the Rongxi Formation in northwestern Hunan and the Ymogantau Formation in the northwestern Tarim. This study provides further evidence for the presence of diverse sinacanthid faunas from the South China plate. As the part of the Zhangjiajie Vertebrate Fauna of China, they have great significance in the paleogeographic division of vertebrates and the regional stratigraphic division and correlation. The Silurian sinacanthids from China were mainly grouped into three assemblages, i.e., the Wentang/Tataertag assemblage (early Telychian), the Fentou/Ymogantau assemblage (middle Telychian), and the Maoshan assemblage (middle to late Telychian). In addition, the sinacanthids from the South China plate, Tarim plate, and Qiongzhong block belong to the Zhangjiajie Vertebrate Fauna and there was certain extent of migration of sinacanthids among these areas during the Telychian, Silurian.

The base of the Devonian is defined at the first appearance of graptolite Uncinatograptus uniformis uniformis, with the occurrence of trilobite Warburgella rugulosa rugosa and conodont Caudicriodus woschmidti as the auxiliary indicators. Recently some researchers questioned whether Caudicriodus woschmidti can be an indicator, and proposed Caudicriodus hesperius to mark the base of the Devonian in carbonate successions. However, the paleogeographic distribution of this species is mainly in the southern hemisphere or near the equator, and there was no definite record of it in the northern hemisphere during the Early Devonian. Due to lithological restrictions, conodont data of the Silruain–Devonian Boundary (SDB) are relatively rare in China, and Caudicriodus hesperius has not been identified. In this study, specimens of Caudicriodus hesperius were obtained from the base of the Kaokesaiergai Formation in the eastern Junggar, northern Xinjiang, which represents the first record of this taxon in China, suggesting that the age of the formation is Early Devonian, rather than late Silurian as previously believed based on the benthic faunas. The encrinurid trilobites, which commonly occur in the Silurian, were also recorded in the same horizon with C. hesperius, indicating that encrinurids may cross the SDB and range into the earliest Devonian. The discovery of Caudicriodus hesperius in northern Xinjiang significantly expands the paleogeographic range of this index conodont to the Central Asian Orogenic Belt in the northern hemisphere, and suggests that Caudicriodus hesperius may be used as a global index for the base of the Devonian and for possible stratigraphic correlation of the SDB in different paleogeographic and paleotectonic settings.

The hard tick Compluriscutula vetulum Poinar and Buckley, 2008 (Ixodida: Ixodidae) from the mid-Cretaceous (ca. 100 Ma) Burmese amber of Myanmar was first described in a new, extinct genus based on a larva. Here, several more larvae are documented providing additional morphological data based on optical studies using a Keyence VHX-6000 Digital Microscope supplemented by computed microtomography (µ-CT). We confirm the presence of 14 festoons (not 13) on the posterior margin of the body, a character unique for the genus. We further describe an unusual pattern of hypostome dentition in the mouthparts, with an unequal and uneven 2/2 arrangement. Moreover, on the internal side of the palps, to the second and third segments five tooth-like elements are present, similar to the hypostome dentition. Fossil ticks are generally very rare, thus the discovery of numerous new specimens of C. vetulum suggests that it may have been relatively common in the Burmese amber forest. Larval instars predominate in the fossil record and we might speculate that they preferred arboricolous hosts.

Longfengshania is among the few examples of Pre-Cryogenian macroscopic fossils with an unambiguous eukaryotic affinity. It has received great attention since this genus is the earliest known Pre-Cryogenian macroalga with blade, stipe, and holdfast differentiation. However, compared to other macrofossils, such as Chuaria and Tawuia, reported occurrences (lithostratigraphic units) of Longfengshania are limited in Tonian strata, restricting the assessment of paleogeographic distribution of Longfengshania and therefore hindering our understanding of its paleoecological role in the Tonian oceans. Here, we describe two new localities of Longfengshania, including the Tonian Shiwangzhuang Formation (∼850–720 Ma) in western Shandong and Jiuliqiao Formation (∼950–720 Ma) in northern Anhui, North China. Specimens of Longfengshania from the Shiwangzhuang and Jiuliqiao formations are smaller than specimens from other localities, which has been interpreted as adaptations to relatively stronger hydrodynamic conditions. Biometric and principal component analyses suggest that most other species of Longfengshania actually fall within the morphospace range of the type species L. stipitata and therefore a re-examination on previously reported specimens and a taxonomic revision for this genus are needed in future study.