{"title":"Fossilized soft tissues in tentaculitids from the Upper Devonian of Armenia: Towards solving the mystery of their phylogenetic affinities","authors":"Olev Vinn , Tamara Hambardzumyan , Elena Temereva , Arayik Grigoryan , Meline Tsatryan , Lusine Harutyunyan , Karine Asatryan , Vahram Serobyan","doi":"10.1016/j.palwor.2024.10.004","DOIUrl":"10.1016/j.palwor.2024.10.004","url":null,"abstract":"<div><div>The tentaculitids represent a significant and diverse group of mysterious fossils found in Palaeozoic strata. Their biology and evolutionary relationships remain poorly understood due to limited information about their soft body anatomy. The discovery of fossilized soft tissues in tentaculitids from the Upper Devonian of Armenia helps to resolve the long-standing mystery of tentaculitid phylogenetic affinities. The thick bundles of phosphatic bars in the tentaculitid interior closely resemble the musculature of several tubicolous invertebrates, such as phoronids and bryozoans. Based on this similarity, we interpret these structures as fossilized muscles of the tentaculitid animal. The attachment of tentaculitid body muscles in a honeycomb pattern to the body wall is unlike that of any mollusc. Based on this muscle arrangement, molluscan affinities of tentaculitoids can be refuted. The muscle arrangement in tentaculitids is more akin to that of bryozoans than to phoronids. Presumably, tentaculitids and bryozoans shared a common ancestor. This ancestor was probably a solitary animal, with coloniality emerging later in the bryozoan branch of the phylogenetic tree. Alternatively, tentaculitoids might have evolved from a bryozoan-like ancestor by losing their coloniality.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100888"},"PeriodicalIF":1.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-10-16DOI: 10.1016/j.palwor.2024.10.001
Ping Liu , Hui Jia , Li Xu , Yu Li , Ming-Yue Luo , Tian-Qi Dong , Jiao Huang , Cheng Quan
{"title":"Early Eocene Metasequoia and Taxodium (Cupressaceae) from Lingbao, Henan Province and their implication for a perhumid climate in central China","authors":"Ping Liu , Hui Jia , Li Xu , Yu Li , Ming-Yue Luo , Tian-Qi Dong , Jiao Huang , Cheng Quan","doi":"10.1016/j.palwor.2024.10.001","DOIUrl":"10.1016/j.palwor.2024.10.001","url":null,"abstract":"<div><div>In this study, fossil leaves of <em>Metasequoia</em> Hu and Cheng, along with leaves and cones of <em>Taxodium</em> Richard, from the lower Eocene of the Xiangcheng Group in Lingbao, Henan Province, central China, were examined. These fossils have been taxonomically assigned to <em>Metasequoia</em> sp. (cf. <em>M</em>. <em>glyptostroboides</em> Hu and Cheng) and <em>Taxodium dubium</em> (Sternberg) Heer. The closest modern relatives are <em>Metasequoia glyptostroboides</em> and <em>Taxodium distichum</em> (Linnaeus) Richard, which typically thrive in humid environments, indicating that similar conditions may have prevailed in early Eocene. Through the Species Distribution Model (SDM) experiment, it was suggested that <em>T</em>. <em>distichum</em> is significantly influenced by precipitation levels, highlighting the importance of moisture in their historical distribution. Moreover, the analysis of the survival environments of native <em>Metasequoia</em> and <em>Taxodium</em> indicates that the annual precipitation in Lingbao during the early Eocene exceeded 1000 mm, which is roughly double the current annual precipitation in the area. This precipitation level is comparable to the present-day subtropical climate zone. During the late Eocene and early Oligocene, the seasonal variation in precipitation was intensified due to the strengthening of the East Asian monsoon, which constrained the seed germination and seedling survival. This may have contributed to the decline in the populations of <em>Metasequoia</em> and <em>Taxodium</em> in East Asia during that period.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100885"},"PeriodicalIF":1.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-10-16DOI: 10.1016/j.palwor.2024.09.006
Fei-Yang Chen , Marissa J. Betts , Zhi-Liang Zhang , Glenn A. Brock
{"title":"The bivalved arthropod Caudicaella aff. bispinata from the Heatherdale Shale (Cambrian Stage 3), South Australia","authors":"Fei-Yang Chen , Marissa J. Betts , Zhi-Liang Zhang , Glenn A. Brock","doi":"10.1016/j.palwor.2024.09.006","DOIUrl":"10.1016/j.palwor.2024.09.006","url":null,"abstract":"<div><div>Sunellids are early Cambrian bivalved arthropods first recognized in South China that are important for understanding the early evolution of the group. However, their taxonomic affinity and distribution beyond South China is poorly known. Furthermore, the relationship between members of the Sunellidae and the globally dispersed <em>Isoxys</em> remains unclear. Recently, rare specimens of the sunellid <em>Caudicaella</em> aff. <em>bispinata</em> have been recovered from the lower Cambrian (Series 2, Stage 3) Heatherdale Shale, eastern Stansbury Basin, South Australia, representing the first record of the group from East Gondwana. <em>Caudicaella</em> aff. <em>bispinata</em> from Australia bears a semicircular carapace, a pair of anterodorsal sulci, anterior and posterior cardinal spines, as well as a distinct thick border or margin. It most closely resembles <em>Caudicaella bispinata</em> from the Shuijingtuo Formation in western Hubei Province, South China. The new discovery adds support for strong faunal similarity of the Konservat-Lagerstätten of South Australia and South China and extends the known geographical range of Cambrian sunellids to East Gondwana. The occurrence of <em>Caudicaella bispinata</em> in South China and <em>Caudicaella</em> aff. <em>bispinata</em> in East Gondwana strengthens the biostratigraphic correlation between those two palaeo-continents.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100882"},"PeriodicalIF":1.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-10-16DOI: 10.1016/j.palwor.2024.09.007
Yong Wang , Zong-Jie Fang , David A.T. Harper , Yu-Chen Zhang , Xin Wei , Guang-Xu Wang , Ren-Bin Zhan
{"title":"New Ordovician bivalves from the Indochina Palaeoplate in Dali, western Yunnan, Southwest China and their palaeogeographic significance","authors":"Yong Wang , Zong-Jie Fang , David A.T. Harper , Yu-Chen Zhang , Xin Wei , Guang-Xu Wang , Ren-Bin Zhan","doi":"10.1016/j.palwor.2024.09.007","DOIUrl":"10.1016/j.palwor.2024.09.007","url":null,"abstract":"<div><div>A centre of radiation for Ordovician bivalves is identified based on an abundant and diverse fauna from the Hsiangyang Formation (Darriwilian, Middle Ordovician) of Dali, western Yunnan, Southwest China. It consists of 22 species of 18 genera including 1) one new genus and four new species: <em>Rhomboconcha tresdentes</em> n. gen. n. sp., <em>Fasciculodonta curvata</em> n. sp., <em>Glyptarca symmetrica</em> n. sp., and <em>Paracyclas initium</em> n. sp.; 2) three taxa known from elsewhere but initially found in Dali: <em>Praeleda</em> sp., <em>Glyptarca</em> sp., and <em>Redonia deshayesi</em>; 3) other taxa previously reported by <span><span>Fang and Cope (2004)</span></span>. Numerical analysis of the distribution of 11 Middle Ordovician bivalve faunas from different regions shows two distinct faunal groups, the HPL group, representing the bivalves that lived in higher palaeolatitudes, and the LPL group (including Australia and South China) in lower palaeolatitudes. The bivalve fauna from Dali correlates with both groups, indicating that the Indochina Palaeoplate was located between these two groups, and in middle–high palaeolatitudes. Thus, the Indochina Palaeoplate was probably an isolated centre for bivalve radiation during the Middle Ordovician; those genera confined to Dali did not then spread to other palaeoplates.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100883"},"PeriodicalIF":1.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-10-16DOI: 10.1016/j.palwor.2024.10.002
Martina Havelcová , Ivana Sýkorová , Petr Rajlich
{"title":"Structural analysis of fossilized tree trunks from the Miocene Mydlovary Formation of the South Bohemian Basin (Czech Republic)","authors":"Martina Havelcová , Ivana Sýkorová , Petr Rajlich","doi":"10.1016/j.palwor.2024.10.002","DOIUrl":"10.1016/j.palwor.2024.10.002","url":null,"abstract":"<div><div>Tree trunks were found in situ in Miocene strata of the Mydlovary Formation of the South Bohemian Basin. Our study presents microscopic and chemical tissue analyses of these tree trunks. The trees were fossilized and flattened. However, they are well preserved, which made the analyses feasible. Good preservation of the tissues is indicated by the high Tissue Preservation Index, the high content of cellulose, and the slightly gelified state of the wood. The Gelification Index indicated that there was only limited alteration during diagenesis. Huminite macerals prevailed over liptinite and inertinite macerals, and two varieties of ulminite and textinite were distinguished, differing in colour reflection, light fluorescence, and reflectance values. The biomarker composition in the extracts of the fossil wood obtained by gas chromatography-mass spectrometry, included terpenoid signatures, supporting a relationship to the Family Cupressaceae s.s.. Gradual burial of the trees is indicated by the fact that they lay crosswise on top of each other. The character of the sedimentary environment and the physiological differences of the trees could explain the deformation and the high degree of preservation.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100886"},"PeriodicalIF":1.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-10-16DOI: 10.1016/j.palwor.2024.09.008
Teng Huang , Qiang-Fen Ma , Xiao-Xin Dong , Guo-Zhen Xu , Yu-Hao Yi
{"title":"Radiolarians from Cambrian Series 2 Niujiaohe Formation in southern Jiangxi, South China","authors":"Teng Huang , Qiang-Fen Ma , Xiao-Xin Dong , Guo-Zhen Xu , Yu-Hao Yi","doi":"10.1016/j.palwor.2024.09.008","DOIUrl":"10.1016/j.palwor.2024.09.008","url":null,"abstract":"<div><div>The origin and early evolution of radiolarian fossils have always provoked great interest among paleontologists. Yet, little is known about the earliest morphological and evolutionary characteristics of radiolarians largely due to the lack of documentation of early Cambrian radiolarian fossils. Herein, we conduct a thorough examination of the basinal Niujiaohe Formation in Chongyi County of southern Jiangxi and report two types of radiolarians: a large number of spherical radiolarians and a minor occurrence of ellipsoidal radiolarian fossils with bipolar rodded spines. The lengths of the spines on ellipsoid radiolarian fossils vary, and typically, the main spines are slightly offset from the polar axis, resulting in an asymmetrical appearance in some specimens. Through systematic taxonomic examination, this radiolarian fossil form is tentatively identified as <em>Beothuka</em> sp. of the spherical polycystine group. The genus <em>Beothuka</em> is commonly found in the Early Ordovician and has not yet been reported in the early Cambrian. Combined with previous reports, four species of radiolarians in three genera are identified from the Niujiaohe Formation in South China, including <em>Paraantygopora porosa</em>, <em>Paraantygopora</em> sp., spherical radiolarian, and <em>Beothuka</em> sp. Overall, the radiolarian fossils in the Niujiaohe Formation are characterized by low diversity and small size, in contrast to the relatively more diverse fauna found in the contemporary shallow-water Shuijingtuo Formation. Therefore, we speculate that radiolarians may have initially originated in shallow water areas and gradually expanded to deep water. This study further enriches the fossil record of the Cambrian Series 2 radiolarians. Combined with relevant data from South China, the radiolarian fauna began to exhibit diversity and complex morphology, indicating the presence of various, advanced spherical-skeletons in early radiolarians, and radiolarians from the early Cambrian appeared to display multiple evolutionary trends.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100884"},"PeriodicalIF":1.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-09-26DOI: 10.1016/j.palwor.2024.09.003
Sirush Khachatryan , Borja Cascales-Miñana , Taniel Danelian , Pierre Breuer , Philippe Steemans , Araik Grigoryan , Ivan Gabrielyan , Vachik Hairapetian , Sylvie Regnier , David Marius Kroeck , Vahram Serobyan
{"title":"First palynological evidence from the Upper Devonian of Armenia (northern Gondwanan margin): biostratigraphic implications","authors":"Sirush Khachatryan , Borja Cascales-Miñana , Taniel Danelian , Pierre Breuer , Philippe Steemans , Araik Grigoryan , Ivan Gabrielyan , Vachik Hairapetian , Sylvie Regnier , David Marius Kroeck , Vahram Serobyan","doi":"10.1016/j.palwor.2024.09.003","DOIUrl":"10.1016/j.palwor.2024.09.003","url":null,"abstract":"<div><div>Diverse and abundant terrestrial palynomorphs are recovered from a Frasnian–Famennian (F-F) succession of shales in the Ertych section, situated in central Armenia. They represent the first discovery of spores from the F-F shallow marine sedimentary sequences of the South Armenian Block, which at that time was part of the northern Gondwanan continental margin. Their taxonomic assessment recognizes 37 spore taxa assigned to 22 genera. Notably, the presence of <em>Teichertospora torquata</em> allows us to assign the entire studied succession to the <em>torquata–gracilis</em> zone, indicating a late Frasnian to early Famennian age. In addition, the occurrence of <em>Acinosporites lindlarensis</em>, which corresponds to the spores of the herbaceous lycophyte <em>Leclercqia</em>, suggests that the age of the studied succession should be further restricted to the late Frasnian. The presence of chitinozoans (i.e., <em>Angochitina mourai</em>) in the studied interval argues for marine deposition. Our biostratigraphic results provide a more coherent picture for the sedimentary evolution of this Frasnian–Famennian sequence arguing for a rather uninterrupted sedimentation close to the critical boundary interval. The identified spore assemblage highlights the close affinity of the Frasnian vegetation preserved in Armenia with other parts of the Northern Gondwana and southern Laurentia. We provide the first evidence of the occurrence of <em>Kraeuselisporites ollii</em> outside Canada and extend its known age range to the late Frasnian.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100879"},"PeriodicalIF":1.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-09-26DOI: 10.1016/j.palwor.2024.09.004
Yuan Gao , Wen-Hao Wu , Fang-Yuan Mao
{"title":"A new marsupialiform from Upper Cretaceous of Songliao Basin, Heilongjiang, China","authors":"Yuan Gao , Wen-Hao Wu , Fang-Yuan Mao","doi":"10.1016/j.palwor.2024.09.004","DOIUrl":"10.1016/j.palwor.2024.09.004","url":null,"abstract":"<div><div>The fossil record of marsupialiforms in the Upper Cretaceous of Asia is scarce, without previous discoveries in China until the current study. Here we report a new marsupialiform, <em>Solatherium nenjiangensis</em> n. gen. n. sp., based on three lower left molars found in the early Campanian Nenjiang Formation at the Bei’an locality of Songliao Basin. The lower molars of <em>S</em>. <em>nenjiangensis</em> exhibit a well-developed entoconid, which is significantly larger than the hypoconulid and the twined entoconid-hypoconulid that is lingually positioned; the entoconid is taller than the hypoconid. These characteristics are consistent with the lower molars of “pediomyids”, placing <em>S</em>. <em>nenjiangensis</em> within the Family “Pediomyidae”. Furthermore, a marsupialiform lower molar is identified as an undetermined species due to its distinct features from those of <em>S</em>. <em>nenjiangensis</em>, indicating a different taxon. This discovery marks the first occurrence of marsupialiform teeth in China and potentially represents the initial recognition of “pediomyids” in Asia, enhancing our understanding of the geographic distribution of marsupialiforms and offering valuable insights into the evolution and migration of metatherians.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 2","pages":"Article 100880"},"PeriodicalIF":1.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143155520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-09-26DOI: 10.1016/j.palwor.2024.09.005
Evgeniy S. Ponomarenko , Rimma M. Ivanova
{"title":"The Moscovian–Kasimovian boundary problem in the Northern Urals: A case study of the Moleben-Iz Section, Ilych River","authors":"Evgeniy S. Ponomarenko , Rimma M. Ivanova","doi":"10.1016/j.palwor.2024.09.005","DOIUrl":"10.1016/j.palwor.2024.09.005","url":null,"abstract":"<div><div>The Kasimovian lower boundary is usually determined by the first appearance of <em>Obsoletes</em> and advanced <em>Protriticites</em> fusulinids; however, this criterion is not always met. In the northern part of the Urals and Pai-Khoi, the Moscovian–Kasimovian boundary is determined by the abrupt appearance of fusulinids of the Subfamily Pulchrellinae. In this paper we present results of our study of the Moleben-Iz section, in an attempt to define the Moscovian–Kasimovian boundary. In this section, the upper Moscovian and lower Kasimovian deposits are represented by shallow-marine carbonates, including a diverse fusulinid complex. The most important stratigraphic level here is the lower part of bed 6, characterized by the abrupt appearance of the fusulinids <em>Kanmeraia</em>, <em>Eowaeringella</em> and <em>Dagmarella</em>. This level is also associated with the diversification of <em>Usvaella</em> (species <em>U</em>. <em>plicata</em> (Shamov and Shcherbovich) and <em>U</em>. <em>porifera</em> Remizova appear) and <em>Pulchrella</em> (<em>Pul</em>. <em>whitensis</em> (Ross and Sabins), <em>Pul</em>. <em>hayasakai</em> (Watanabe), and <em>Pul</em>. <em>pokojamensis</em> (Lebedeva) appear). The later appearance of <em>Obsoletes obsoletus</em> may be related to the later migration of this species from the Russian platform to the Urals. Placement of the Kasimovian lower boundary in the Northern Urals and Pai-Khoi at the base of the <em>Kanmeraia ozawai</em>-<em>Usvaella usvae</em> Biozone allows us to correlate this boundary with the Missourian base of the North American continent.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 3","pages":"Article 100881"},"PeriodicalIF":1.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
PalaeoworldPub Date : 2024-09-21DOI: 10.1016/j.palwor.2024.09.002
Zhen-Yu Song , Edmund A. Jarzembowski , Chuan-Tao Xiao , Ai-Ying Yang
{"title":"New Jurassic notocupedins (Coleoptera: Archostemata: Ommatidae) from the Qinghai-Xizang (Tibetan) Plateau","authors":"Zhen-Yu Song , Edmund A. Jarzembowski , Chuan-Tao Xiao , Ai-Ying Yang","doi":"10.1016/j.palwor.2024.09.002","DOIUrl":"10.1016/j.palwor.2024.09.002","url":null,"abstract":"<div><div>Beetles belonging to the extinct tribe Notocupedini (Archostemata: Ommatidae) are widespread in Mesozoic deposits. Two new Early Jurassic species in the first reported Mesozoic insect assemblage from the Qinghai-Xizang (Tibetan) Plateau are proposed in the genus/collective group <em>Zygadenia</em>. <em>Zygadenia dachaidanensis</em> n. sp. can be distinguished from other congeners based on a combination of small size, oval head, large eyes, absence of longitudinal suture on metasternum, slightly narrowed elytron below humerus, maculated round window cells, and sub-rectangular scutellum; <em>Zygadenia haixiensis</em> n. sp. can be distinguished from other congeners based on a combination of elongated head, uniquely contracted ventrite 5, metasternum with longitudinal suture and elytron without prominent longitudinal veins. The two species represent the first record of Archostemata from the Qinghai-Xizang Plateau, extending the palaeogeographical distribution of Archostemata, and are important an aid to the reconstruction of the Early Jurassic swamp ecosystem in the Qinghai-Xizang Plateau.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 4","pages":"Article 100878"},"PeriodicalIF":1.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}