Dayou Zhai

• Doctor of Philosophy
• Research Professor at Yunnan University

We describe Cavernocypris xiangisp. nov., the eighth nominated species of the genus, from two localities in Yunnan Province of southwestern China. As a member of Cavernocypris Hartmann, 1964, C. xiangisp. nov. has short swimming setae on the second antenna, and its left valve overlaps the right valve on the ventral side. It can be distinguished fro...

Ostracods have frequently been reported as part of the active faunas in the wet phase of rice fields, but knowledge on the dormant ostracods during the dry period of the rice cycle has been limited, hindering a comprehensive understanding of their adaptation to the rice field environment. In this study, we record 11 dormant ostracod species by incu...

Previous studies of the Recent non-marine ostracods of Yunnan Province in southwestern China yielded 42 species, among which only 18 species were reported based on living material. Such a low number is likely to underestimate the species diversity of ostracods in Yunnan, considering the geographical disparity among its different parts. In this stud...

Population age structure, preservation, and carapace abundance of the valve remains of Limnocythere inopinata in 88 surface-sediment samples from Lakes Daihai, Dali, and Hulun were examined to better understand taphonomy of limnic ostracods. The spatial changes in population structure of L. inopinata match the within-lake hydraulic gradients, with...

Graphical Abstract Highlights d The Chengjiang euarthropod Ercaicunia multinodosa preserves appendages in 3D d Head appendages include antennulae, differentiated antennae, mandibles, and maxillae d Trunk appendages are biramous with proximal epipodites d Ercaicunia represents the first stem-group pancrustacean known from macrofossils In Brief Zhai...

Research on non-marine ostracods in Yunnan Province, especially in desiccated and irrigation environments, is limited, restricting our understanding of their survival strategies, adaptation mechanisms, and biogeographical patterns within this region. The present study investigates ostracods across 43 sites in eastern Yunnan, including desiccated ri...

Pectocaris species are intermediate- to large-sized Cambrian bivalved arthropods. Previous studies have documented Pectocaris exclusively from the Cambrian Series 2 Stage 3 Chengjiang biota in Yu’anshan Formation, Chiungchussu Stage in SW China. In this study, we report Pectocaris paraspatiosa sp. nov., and three other previously known Pectocaris f...

Early euarthropod evolution involved a major transition from lobopodian-like taxa to organisms featuring a segmented, well-sclerotized trunk (arthrodization) and limbs (arthropodization). However, the precise origin of a completely arthrodized trunk and arthropodized ventral biramous appendages remain controversial, as well as the early onset of an...

Lake sediments that widely distributed in the active and complicated fault zones have been recently showing great potential for paleoseismic reconstruction. However, flood events and human activities may make the seismic signal unrecognizable. In this study, high-resolution analyses of sedimentary structure, physical and chemical proxies, as well a...

Ilyocypris leptolinea Wang & Zhai, sp. nov. is described from late Quaternary sediments in central-eastern Inner Mongolia, northern China. The new species, which has a carapace shape and pitted surface typical of the genus, is characterised by double rows of fine, densely arranged marginal ripplets, separated by an inner list, along both anterior a...

Despite previous scientific investigations on the limnic ostracods in eastern Inner Mongolia, the ostracod assemblages in aquatic habitats other than the large brackish lakes in this region have been poorly studied, hampering comprehensive knowledge of the regional ostracod fauna. Here we analyze the ostracod assemblages in various surface waters i...

Limnocythere inopinata (Baird, 1843) is a widely distributed ostracod in modern non-marine waters and Quaternary sediments. Based on its morphological variation (the number and position of its nodes), different phenotypes have been identified. However, the factors controlling its morphological variation are currently open to debate, which hinders p...

2022) Three new species of non-marine ostracods (Crustacea, Ostracoda) from small water bodies of northern China. Abstract Three new species, Pseudocandona cheni sp. nov., Cyclocypris pangi sp. nov., and Tonnacypris rectangularis sp. nov., collected from northern China, are described in this study. Pseudocandona cheni, of the compressa group, is di...

The Cambrian Stage 3 Chengjiang biota in South China is one of the most influential Konservat-Lagerstätten worldwide thanks to the fossilization of diverse non-biomineralizing organisms through pyritization. Despite their contributions to understanding the evolution of early animals, several Chengjiang species remain poorly known owing to their sca...

We analyze 31 surface-sediment samples from the depths of 2–33 m in the large fresh-water Lake Ngoring on the northeastern Tibet–Qinghai Plateau to provide depth-preference information of ostracods valuable for palaeo-bathymetric reconstruction. Among the nine species discovered, Tonnacypris estonica and Ilyocypris echinata show clear preferences t...

The Cambrian fossil record has produced remarkable insights into the origin of euarthropods, particularly the evolution of their versatile body plan of segments bearing specialized, jointed appendages for different functions including feeding and locomotion [01, 02]. Early euarthropod evolution involved a major transition from lobopodian-like taxa...

The Cambrian Stage 3 Chengjiang biota in South China is one of the most influential Konservat-Lagerstätten worldwide thanks to the fossilization of diverse non-biomineralizing organisms through pyritization. Despite their contributions to understanding the evolution of early animals, several Chengjiang species remain poorly known due to their scarc...

The fossil record, including the record of Burgess Shale-type deposits, is biased towards late ontogenetic stages. Larval stages, juvenile and subadult specimens exist but are very rare and often preserved as phosphatic fossils, resulting in biased population structures. Here, we report a new Burgess Shale-type Lagerstätte from Haiyan, China. The H...

The last common ancestor of all living arthropods had biramous postantennal appendages, with an endopodite and exopodite branching off the limb base. Morphological evidence for homology of these rami between crustaceans and chelicerates has, however, been challenged by data from clonal composition and from knockout of leg patterning genes. Cambrian...

Although first described in 1999, the early Cambrian Pectocaris remains a poorly known euarthropod genus. Two species, Pectocaris eurypetala and P. spatiosa, have been described from the Chengjiang biota. Here, we report a third species, Pectocaris inopinata sp. nov., which bears a pair of stalked eyes attached to an anterior sclerite, a pair of sh...

Studies of Holocene ostracods of the Tibetan Plateau have mostly centred around valves and carapaces collected from lake sediments, some at or near the substrate surface and others from short cores. Reports from habitats other than lakes are scarce, and few living species found in this region have appendages described, hindering further taxonomic a...

Understanding the functional morphology and mobility of appendages of fossil animals is important for exploring ecological traits such as feeding and locomotion. Previous work on fossils from the 518 million‐year‐old Chengjiang biota of China was based mainly on two‐dimensional information captured from the surface of the specimens. Only recently,...

Bushizheia yangi gen. et sp. nov. is a euarthropod species from the Cambrian (Series 2, Stage 3) Chengjiang Lagerstätte, Southwest China. Sclerotised dorsal terg-ites, sclerotisation of post-frontal head limb appendages, and no isolated cephalic sclerite support the euarthropod affinities of B. yangi gen. et sp. nov. However, the frontal head limbs...

The phylum of annelids is one of the most disparate animal phyla and encompasses ambush predators, suspension feeders and terrestrial earthworms1. The early evolution of annelids remains obscure or controversial2,3, partly owing to discordance between molecular phylogenies and fossils2,4. Annelid fossils from the Cambrian period have morphologies t...

The euarthropod head is a highly versatile and functionally specialized body region composed of multiple appendage-bearing segments and whose complex evolution has been scrutinized through anatomical, developmental, and paleontological approaches [1 , 2 , 3 , 4 ]. Exceptionally preserved Cambrian fossils have allowed for the reconstruction of criti...

Background The Chengjiang biota is one of the most species-rich Cambrian Konservat-Lagerstätten, and preserves a community dominated by non-biomineralized euarthropods. However, several Chengjiang euarthropods have an unfamiliar morphology, are extremely rare, or incompletely preserved. Results We employed micro-computed tomography to restudy the...

Radiodonts are a diverse clade of Lower Palaeozoic stem-group euarthropods that played a key role in the emergence of complex marine trophic webs. The latest addition to the group, Cambroraster falcatus, was recently described from the Wuliuan Burgess Shale, and is characterized by a unique horseshoe-shaped central carapace element. Here we report...

Trilobitomorphs are a species-rich Palaeozoic arthropod assemblage that unites trilobites with several other lineages that share similar appendage structure. Post-embryonic development of the exoskeleton is well documented for some trilobitomorphs, especially trilobites, but little is known of the ontogeny of their soft parts, limiting understandin...

Traditionally, the origin and evolution of modern arthropod body plans has been revealed through increasing levels of appendage specialisation exhibited by Cambrian euarthropods. Here we show significant variation in limb morphologies and patterns of limb-tagmosis among three early Cambrian arthropod species conventionally assigned to the Bradoriid...

Ilyocypris species are abundant and widespread in North East Asian rice fields, but for many species their taxonomy is poorly defined, which negatively impacts ecological studies on rice field ecosystems. Herein, two of these species, Ilyocypris dentifera Sars, 1903 and Ilyocypris japonica Okubo, 1990, are redescribed, and a third species, Ilyocypr...

Background: Artiopodan euarthropods represent common and abundant faunal components in sites with exceptional preservation during the Cambrian. The Chengjiang biota in South China contains numerous taxa that are exclusively known from this deposit, and thus offer a unique perspective on euarthropod diversity during the early Cambrian. One such end...

The 4.2 ka BP event has been widely investigated since it was suggested to be a possible cause for the collapse of ancient civilizations. With the growth of proxy records for decades, however, both its nature and its spatial pattern have become controversial. Here we examined multi-proxy data of the grain-size distribution, ostracode assemblage, po...

The Cambrian Explosion represents a major metazoan radiation event, which is reflected in the dramatic increase of both taxonomic and ecological diversity. In light of recent fossil discoveries from exceptionally preserved Cambrian lagerstätten, the ecological complexity and trophic structures of these Cambrian marine communities has been further r...

Symbiotic relationships are widespread in terrestrial and aquatic animals today, but evidence of symbiosis in the fossil record between soft-bodied bilaterians where the symbiont is intimately associated with the integument of the host is extremely rare. The radiation of metazoan life apparent in the Ediacaran (~635–541 million years ago) and Cambr...

p class="Standard">Ostracods are very common in rice fields and they can have a significant influence on the rice field ecosystem. They can reach very high densities, often higher than other meiofauna, and their activities can have both positive and negative effects on rice harvests. They directly affect nutrient recycling through excretion, and in...

We measured selected podomeres, setae and claws in different ostracods and calculated the between-specimen morphological difference, which is expressed as a Canberra dissimilarity index. Our data indicate that morphological differences between ostracods increase with their taxonomic distance. Cluster analyses of ostracod specimens based on Canberra...

Preliminary investigations of urban waters in Beijing City and small water-bodies in Inner Mongolia yielded a total of 12 living ostracod species. Five species are new records for China: Candona quasiakaina Karanovic & Lee, 2012, Fabaeformiscandona myllaina Smith & Kamiya, 2007, Heterocypris auricularis sp. nov. (previously known as Heterocypris sa...

Most existing studies of lacustrine ostracodes have been focused on species composition, and little attention has been paid to population structure. In this study, 39 surface-sediment samples from Hulun Lake, Inner Mongolia, were analyzed for ostracode species composition and 17 of them also for population structure of Limnocythere inopinata, which...

Grain-size distributions of fluvial, eolian and marine sediments were explicated decades ago. For lake sediments, however, there is still great uncertainty in explaining the genesis of grain-size components due to the inherent complexity of their polymodal distributions. In this study, the grain-size components of the surface sediments of Daihai La...

It is widely recognized that lake sediment grain‐size distributions tend to be polymodal and consist of two or more grain‐size components. However, for specific cases, the genesis of each component usually is poorly understood. In this study, the grain‐size components of the surface sediments of Hulun Lake, Inner Mongolia, were partitioned using th...

A sediment core from Hulun Lake, Inner Mongolia was analyzed for species assemblages and shell chemistry of ostracodes to investigate changes in the hydrology and climate of the East Asian summer monsoon margin during the Holocene. Darwinula stevensoni was abundant, Ilyocypris spp. scarce, littoral ostracodes absent and Mg/Ca, Sr/Ca and δ18O were l...

It has been recognized long ago that Limnocythere inopinata is a widely distributed ostracod and comprises various phenotypes. The taxonomy of the different phenotypes and their ecological differences, however, are still under debate. In this study, we investigated the relationships between ostracod distribution, water depth, and the substrate base...

Pollen-assemblage data from a sediment core from Hulun Lake in northeastern Inner Mongolia describe the changes in the vegetation and climate of the East Asian monsoon margin during the Holocene. Dry steppe dominated the lake basin from ca. 11,000 to 8000 cal yr BP, suggesting a warm and dry climate. Grasses and birch forests expanded 8000 to 6400...

Wen, R. L., Xiao, J. L., Chang, Z. G., Zhai, D. Y., Xu, Q. H., Li, Y. C. & Itoh, S. 2009: Holocene precipitation and temperature variations in the East Asian monsoonal margin from pollen data from Hulun Lake in northeastern Inner Mongolia, China. Boreas , 10.1111/j.1502‐3885.2009.00125.x. ISSN 0300‐9483. Quantitative palaeoclimatic reconstruction w...

A 170 cm long sediment core spanning the last 10 000 years was recovered from Hulun Lake in the northeastern margin of the East Asian summer monsoon. The sediment core was analyzed at 1 cm intervals for grain-size distribution and sedimentary component partition. These data provide a proxy record of the monsoon variability on millennial to centenni...

Lacustrine records from the northern margin of the East Asian monsoon generate a conflicting picture of Holocene monsoonal precipitation change. To seek an integrated view of East Asian monsoon variability during the Holocene, an 8.5-m-long sediment core recovered in the depocenter of Dali Lake in central-eastern Inner Mongolia was analyzed at 1-cm...