Dtsch. Entomol. Z. 68 (2) 2021, 299-308 | DOI 10.3897/dez.68.71880 > PENSUFT. ee BERLIN Limnomma, a new genus of Ommatidae from the Middle Jurassic Daohugou beds (Coleoptera, Archostemata) Yan-Da Li’, Erik Tihelka*, Hong Pang?, Di- Ying Huang’, Chen-Yang Cai’ 1 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Centre for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China 2 School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK 3 State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou 510275, China http://zoobank.org/DD8 10A92-CEAC-4333-99B6-3AE2 1A0D12B6 Corresponding author: Chen-Yang Cai (cycai@nigpas.ac.cn) Academic editor: Sonja Wedmann @# Received 20 July 2021 # Accepted 20 August 2021 # Published 3 September 2021 Abstract The relictual archostematan beetle family Ommatidae attained high diversity during the Mesozoic. Despite their once high taxonomic diversity and morphological disparity, many Mesozoic ommatid taxa remain poorly understood, partly due to limited preservation. Here we report an exceptionally well-preserved fossil, which we describe as a new ommatid genus and species, Limnomma dao- hugouense gen. et sp. nov., from the mid-Jurassic Daohugou Lagerstatte in Northeast China. The new genus can be most easily distinguished from other ommatids by the presence of a circular non-tuberculate region on ventrite 5. The new taxon is discussed in relation to the classification of the Mesozoic genera Brochocoleus and Burmocoleus. Key Words Archostemata, Daohugou, Jurassic, Limnomma, Ommatidae Introduction Ommatidae is a small family in the beetle suborder Ar- chostemata. While the group has been historically treated as a Subfamily of the superficially similar-looking Cupedi- dae by some authors (e.g. Ponomarenko 1969), recent tran- scriptomic analyses have recovered ommatids as the sister group of Micromalthidae, hence supporting their status as a separate family (McKenna et al. 2019). Only three extant genera and seven species of Ommatidae are known from Australia and South America (Hornschemeyer and Beutel 2016, Escalona et al. 2020). However, this currently relict- ual family had a high diversity in the Mesozoic. Numerous fossil genera have been discovered from fossil sites across the continents of Europe and Asia (e.g. Ponomarenko 1969, Tan and Ren 2009, Kirejtshuk 2020). Though many fossil archostematans (including ommatids) have been found in China in the 20" century (e.g. Hong 1982, 1983, Ren 1995), most of them are rather poorly preserved and are, therefore, of limited taxonomic and phylogenetic value. The discov- ery of well-preserved ommatid in compression-impression fossils in northeastern China (Tan and Ren 2009, Tan et al. 2012) and in amber from northern Myanmar (e.g. Ya- mamoto 2017, Jarzembowski et al. 2018, Li et al. 2020a, Tihelka et al. 2020) over the last decade greatly enhanced our understanding of the family’s diversity. The Middle Jurassic Daohugou beds represent a fa- mous Jurassic Lagerstaétte in Northeast China (Huang 2016). The fossil-bearing deposits at Daohugou have been correlated with the Haifanggou Formation at Beipiao (as summarised in Lian et al. 2021). Based on isotope analy- ses, the Daohugou beds have been dated to approximately 165 Ma (Chen et al. 2004, Yang and Li 2008). More than 700 insect species have been described from Daohugou beds over the past 20 years, including representatives of 23 orders (Lian et al. 2021). Many fossils from the Copyright Yan-Da Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 300 Daohugou beds are exceptionally well-preserved with remarkably fine details, providing invaluable information on the biology of these extinct organisms (e.g. Gao et al. 2012, Huang et al. 2013, Cai et al. 2014). Considering the high biodiversity of Ommatidae in the Mesozoic, the ommatids from the Daohugou beds remain insufficiently studied, with only six species reported to date (Tan and Ren 2009, Tan et al. 2012). In this study, we report a new genus of Ommatidae from Daohugou, which further extends our knowledge on the morphological di- versity of Mesozoic Ommatidae. Materials and methods The compression fossil studied herein (Figs 1—5) origi- nates from Daohugou Village, Ningcheng County, Inner Mongolia, China (~ 165 Ma). Additional fossil omma- tids from Burmese amber (Noije Bum, Hukawng Valley, Kachin State, northern Myanmar; ~ 99 Ma) were also ex- Yan-Da Li et al.: Limnomma gen. nov. from Daohugou amined for comparison. The amber pieces were trimmed with a small table saw, ground with emery papers of different grit sizes, and finally polished with polishing powder. The specimen CNU-COL-BR2014808 (Burmo- coleus zhiyuani) is deposited in the Capital Normal Uni- versity, Beijing, China. All other specimens are deposit- ed in the Nanjing Institute of Geology and Palaeontology (NIGP), Chinese Academy of Sciences, Nanjing, China. Photographs under incident light were taken with a Zeiss Discovery V20 stereo microscope. Where nec- essary, compression fossils were moistened with 70% ethanol to improve the contrast of morphological char- acters. Widefield fluorescence images were captured with a Zeiss Axio Imager 2 light microscope combined with a fluorescence imaging system. Images under incident light and widefield fluorescence were stacked in Helicon Focus 7.0.2 or Zerene Stacker 1.04. Scanning electron microscopic (SEM) images were obtained with a Hitachi SU 3500 scanning electron microscope, operating with an accelerating voltage of 15 kV and a pressure of 80 Pa. A. Part, NIGP176015a; B. Counterpart, NIGP176015b. Scale bars: 4 mm. dez.pensoft.net Dtsch. Entomol. Z. 68 (2) 2021, 299-308 Figure 2. General habitus of Limnomma daohugouense gen. et sp. nov., holotype, NIGP176015, moistened with 70% ethanol, under incident light. A. Part, NIGP176015a; B. Counterpart, NIGP176015b. Scale bars: 4 mm. The following specimens were examined for this study: Limnomma daohugouense gen. et sp. nov.: NIGP176015 (holotype). Burmocoleus zhiyuani (Liu et al., 2017): CNU-COL- BR2014808 (holotype). Burmocoleus prisnyi Kirejtshuk, 2020: NIGP176016. Burmocoleus sp.: NIGP176017. Systematic palaeontology Order Coleoptera Linnaeus, 1758 Suborder Archostemata Kolbe, 1908 Family Ommatidae Sharp & Muir, 1912 Genus Limnomma Li & Cai, gen. nov. http://zoobank.org/1C7A821-3CE6-43FC-ABAB-D8092B6D8 126 Type species. Limnomma daohugouense sp. nov. Etymology. The generic name is derived from the Greek “limne”, meaning lake, referring to its habitats around the Daohugou palaeolakes, and the generic name “Omma’’, the type genus of Ommatidae. The name is neu- ter in gender. Diagnosis. Head elongate, without distinct protu- berances. Antennae subfiliform; antennomere 3 more than twice as long as 4. Antennal grooves absent. Gula sutures long, almost reaching posterior edge of head. Pronotal disc subtrapezoidal, with maximum width near base; lateral edges dentate. Elytra with distinct explanate epipleura; each epipleuron with only two rows of window punctures. Abdominal ventrites abutting; ventrite 5 with a slightly raised circular non-tuberculate region. Remarks. The circular non-tuberculate region on ventrite 5 is the most important character differentiating Limnomma from all other extant or extinct ommatids. The shape of head, prothorax, and elytral epipleura could serve as additional characters differentiating Limnomma from other Brochocoleus-like fossils. dez.pensoft.net Yan-Da Li et al.: Limnomma gen. nov. from Daohugou Figure 3. Details of Limnomma daohugouense gen. et sp. nov., holotype, NIGP176015a, under scanning electron microscopy. A. Head; B. Prothorax; C. Elytral base; D. Middle part of elytra; E. Elytra, with carbon film of abdominal ventrites partially showing; F. Elytral apex. Abbreviations: anl—4, antennomeres 1-4; el, elytron; exep, explanate epipleuron; ey, compound eye; pf, profemur; pn, pronotum; v1—5, ventrites 1-5. Scale bars: 1 mm. Limnomma daohugouense Li & Cai, sp. nov. https://zoobank.org/92EE1D83-E65B-4345-A343-694ECB200884 Figures 1—5 Material. Holotype, NIGP176015. Locality and horizon. Daohugou Village, Ningcheng County, Inner Mongolia, China. Middle Jurassic, Hai- fanggou Formation. dez.pensoft.net Diagnosis. As for the genus. Description. Body elongate, covered with rounded tubercles. Head prognathous, elongate, constricted posteriorly to form a neck; dorsal surface without prominent posterior protuberances (Fig. 3A). Compound eyes protruding lat- erally (Fig. SH). Antennal insertion area located antero- laterally. Antennal grooves absent. Postocular temples Dtsch. Entomol. Z. 68 (2) 2021, 299-308 Figure 4. Details of Limnomma daohugouense gen. et sp. nov., holotype, NIGP176015b, under scanning electron microscopy. A. Head, with gula sutures highlighted (arrowhead); B. Prothorax; C. Mesothorax; D. Metathorax; E. Middle part of abdomen; F. Abdominal apex. Abbreviations: an2—4, antennomeres 2—4; el, elytron; ey, compound eye; msc, mesocoxa; msv, mesoventrite; mtv, metaventrite; pf, profemur; pp, propleuron; ps, prosternum; v2—5, ventrites 2-5. Scale bars: | mm. not prominent. Antenna 11-segmented, short, extending beyond anterior prothoracic margin when posteriorly di- rected, but not reaching posterior prothoracic margin, with thin and short setae; antennomere 1 wider than other an- tennomeres; antennomere 2 distinctly small, subquadrate, about as wide as long; antennomere 3 elongate, 2.6 times as long as 4; antennomeres 4—10 short, subequal in length; antennomere 11 tapering apically. Mandibles probably with vertical cutting edges (Fig. 5A). Gula sutures long, (almost) reaching posterior edge of head (Fig. 4A). Pronotal disc subtrapezoidal, with maximum width near base, distinctly narrower than hind body (Fig. 3B); lateral edges dentate (Fig. 5D). Pronotal hypomeron very narrow. Propleura reaching anterior margin of prothorax (Fig. 4B). Prosternum (Fig. 4B) comparatively large, quadrate:; prosternal process short. Procoxae contiguous. dez.pensoft.net 304 Yan-Da Li et al.: Limnomma gen. nov. from Daohugou Figure 5. Details of Limnomma daohugouense gen. et sp. nov., holotype, NIGP176015, under scanning electron microscopy. A-G. NIGP176015a; A. Mouthparts; B. Antennomeres 2 and 3; C. Antennomeres 7 and 8; D. Dentate lateral edge of pronotal disc (arrowhead); E. Scutellum; F. Elytral disc; G. Explanate epipleuron; H—I. NIGP176015b; H. Compound eye; I. Non-tuberculate circular region on ventrite 5. Abbreviations: anl—8, antennomeres 1-8; exep, explanate epipleuron; ey, compound eye; gs, gula suture; md, mandible; pn, pronotum; sc, scutellum; wp, window punctures. Scale bars: 500 um. Elytra elongate; each elytron with probably ten longi- tudinal rows of transverse maculated window punctures on disc and two rows of larger maculated window punc- tures on explanate epipleuron (Fig. 3C—F); longitudinal ridges (elytral veins) indistinct, with rounded tubercles (Fig. SF). Mesoventrite with discrimen on posterior half (Fig. 4C). Mesocoxae contiguous. Metaventrite subtrape- zoidal, with discrimen and katepisternal suture (Fig. 4D). Metacoxae transverse, contiguous. dez.pensoft.net Abdomen broad, with five coplanar ventrites, separated by distinct grooves; ventrites 2—5 subequal in length (Fig. 4E, F); ventrites 5 with a slightly raised non-tuberculate circular region in the middle (Fig. 51). Measurements of holotype. Body length, 21.8 mm; body width, 9.7 mm; head length (including neck), 3.9 mm; head width (including eyes), 2.3 mm; pronotal length, 4.1 mm; pronotal width, 3.0 mm; elytral length, 13.8 mm; elytral width (single), 4.8 mm. Dtsch. Entomol. Z. 68 (2) 2021, 299-308 305 Figure 6. General habitus of Burmocoleus, under incident light. A, B. Burmocoleus prisnyi, NIGP176016; A. Dorsal view; B. Ventral view; C, D. Burmocoleus sp., NIGP176017; C. Dorsal view; D. Ventral view. Scale bars: 3 mm. dez.pensoft.net 306 Ps a. Y x v a . = ag “pee G = ~ ie we : a A “2 ve, 1 kg 5 = 3 iM Figure 7. Morphological details of Burmocoleus, under widefield fluorescence. A-H. Burmocoleus prisnyi, NIGP176016; Yan-Da Li et al.: Limnomma gen. nov. from Daohugou ss < i see A. Mouthparts, ventral view; B. Mouthparts, dorsal view; C. Antenna, dorsal view; D. Procoxae, ventral view; E. Mesotarsus, ven- tral view; F. Hind leg, ventral view; G. Base of explanate epipleuron, dorsal view; H. Abdominal base, ventral view; I. Burmocoleus zhiyuani, holotype, CNU-COL-BR2014808, abdominal apex, ventral view. Abbreviations: anl—4, antennomeres 1-4; exep, expla- nate epipleuron; lbp, labial palp; md, mandible; mstl—5, mesotarsomeres 1—5; msv, mesoventrite; mtc, metacoxa; mtf, metafemur; mttb, metatibia; mttc, metatrochanter; mxp, maxillary palp; pc, procoxa; ps, prosternum; ptc, protrochanter; sc, scutellum; v1—5, ventrites 1—5. Scale bars: 500 um. Discussion Brochocoleus Hong is a problematic fossil genus in Om- matidae. The first species assigned to this genus, Br. punc- tatus Hong, was described based on an isolated elytron (Hong 1982). Later, numerous Mesozoic fossils across Europe and Asia with wide explanate epipleura have been placed into Brochocoleus (e.g. Ponomarenko 1994, Tan and Ren 2009, Jarzembowski et al. 2013b). In a recent review, Kirejtshuk (2020) moved the Brochocoleus spe- dez.pensoft.net cies from Burmese amber to two new genera, and divided the majority of remaining species into Brochocoleus s.s. and Diluticupes Ren. This division was mainly based on differences in elytral venation. Though in some omma- tids there are clear fusions between elytral veins, in many other ommatids the veins become weak and hardly trace- able near the elytral apex. Thus, we think Kirejtshuk’s division of Brochocoleus into Brochocoleus s.s. and Di- /uticupes is not supported by the available morphological evidence. Nevertheless, we agree that the current Brocho- Dtsch. Entomol. Z. 68 (2) 2021, 299-308 coleus is probably a heterogenous assemblage and needs further revision. The discovery of the aberrant ommatid Stegocoleus Jarzembowski and Wang demonstrated that the wide explanate epipleura could have evolved multiple times within Ommatidae (Jarzembowski and Wang 2016, Li et al. 2020b). Thus, wide epipleura alone cannot be regarded as a diagnostic character uniting the otherwise dissimilar species placed into Brochocoleus. Limnomma gen. nov. is somewhat similar to the previously known fossils assigned to Brochocoleus in having distinct explanate epipleura. However, the new fossil can be easily differentiated from all previously-re- ported Brochocoleus-like fossils. In species assigned to Brochocoleus, the explanate epipleura are always wider and with more rows of window punctures in the basal region. In contrast, the explanate epipleura of Limnom- ma only have two rows of window punctures extending from the elytral base to the apex, and the epipleural width remains almost the same along the entire length. The epipleura of Limnomma are somewhat similar to Burmo- coleus Kirejtshuk (Figs 6, 7), where the additional row of window punctures in the basal region is sometimes reduced and appears as a single window puncture (fig. 5C in Kirejtshuk 2020). However, the head and thorac- ic morphology of Limnomma differs distinctly from that of Burmocoleus. The pronotal disc of Burmoco- leus is flattened and oval, reaching its maximum width at the middle, while the pronotal disc of Limnomma is subtrapezoidal, with maximum width near the base. The head of Burmocoleus is nearly as long as wide, while in Limnomma, the head is distinctly narrower. Besides, the gula sutures are present in Limnomma, but are absent in Burmocoleus (Fig. 6B). The most notable character, differentiating Limnomma from all other ommatids, is the comparatively smooth cir- cular region on the ultimate abdominal ventrite (Fig. 51). The body surface of Limnomma, like other ommatids, is covered with rounded tubercles (Figs 3 and 4). However, in Limnomma, there is a slightly raised circular region with- out tubercles in the middle of ventrite 5. This character is absent in extant archostematans and has likewise not been previously reported in other fossils in this group. In the relatively well-preserved ommatids in Burmese amber we examined, we found no trace of such a smooth region (e.g. Fig. 71). In Lepicerus (Myxophaga: Lepiceridae), there is a similar raised circular setose region on the last ventrite (fig. 11 in Shepard et al. 2005); however, its function has not been reported. We suppose that the raised circular region in Limnomma might have been involved in sensory or excre- tory function, although this is admittedly difficult to verify. Acknowledgements We are grateful to Chun-Zhao Wang for technical help in SEM imaging, Dong Ren for help in arranging a loan of the holotype of Burmocoleus zhiyuani, and Dao-Jun Yuan for help in inspecting the type specimens deposited at NIGP. We 307 thank Shihei Yamamoto and one anonymous reviewer for the helpful comments. Financial support was provided by the Strategic Priority Research Program of the Chinese Acade- my of Sciences (XDB26000000 and XDB18000000), the National Natural Science Foundation of China (41688103 and 41730317) , and the Second Tibetan Plateau Scientific Expedition and Research Project (2019QZKK0706). References Cai C-Y, Thayer MK, Engel MS, Newton AF, Ortega-Blanco J, Wang B, Wang X-D, Huang D-Y (2014) Early origin of parental care in Meso- zoic carrion beetles. Proceedings of the National Academy of Scienc- es USA 111: 14170-14174. https://doi.org/10.1073/pnas.1412280111 Chen W, Ji Q, Liu D-Y, Zhang Y, Song B, Liu X-Y (2004) Isotope geochro- nology of the fossil-bearing beds in the Daohugou area, Ningcheng, In- ner Mongolia. Regional Geology of China 23: 1165-1169. [In Chinese] Escalona HE, Lawrence JF, Slipifski A (2020) The extant species of the genus Omma Newman and description of Beutelius gen. nov. (Co- leoptera: Archostemata: Ommatidae: Ommatinae). Zootaxa 4728: 547-574. https://doi.org/10.11646/zootaxa.4728.4.11 Gao T-P, Shih C-K, Xu X, Wang S, Ren D (2012) Mid-Mesozoic flea- like ectoparasites of feathered or haired vertebrates. Current Biology 22: 732-735. https://doi.org/10.1016/j.cub.2012.03.012 Hong Y-C (1982) Mesozoic Fossil Insects of the Jiuquan Basin in Gansu Province. Geological Publishing House, Beijing, 187 pp. [In Chinese] Hong Y-C (1983) Middle Jurassic Fossil Insects in North China. Geo- logical Publishing House, Beijing, 223 pp. [In Chinese] Hornschemeyer T, Beutel RG (2016) Ommatidae Sharp & Muir, 1912. In: Beutel RG, Leschen RAB (Eds) Handbook of Zoology, Arthrop- oda: Insecta, Coleoptera, beetles, Vol. 1: morphology and systemat- ics (Archostemata, Adephaga, Myxophaga, Polyphaga partim). 2™ edn. Walter de Gruyter, Berlin and Boston, MA, 52-56. https://doi. org/10.1515/9783 110373929-008 Huang D-Y [Ed.] (2016) The Daohugou Biota. Shanghai Scientific and Technical Publishers, Shanghai, 332 pp. [In Chinese] Huang D, Nel A, Cai C, Lin Q, Engel MS (2013) Amphibious flies and paedomorphism in the Jurassic period. Nature 495: 94-97. https:// doi.org/10.1038/nature11898 Jarzembowski EA, Yan EV, Wang B, Zhang H (2013) Brochocolein beetles (Insecta: Coleoptera) from the Lower Cretaceous of north- east China and southern England. Cretaceous Research 44: 1-11. https://doi.org/10.1016/).cretres.2013.03.003 Jarzembowski EA, Wang B (2016) An unusual basal beetle from Myan- mar (Coleoptera: Archostemata). Alcheringa: An Australasian Jour- nal of Palaeontology 40(2): 297-302. https://doi.org/10.1080/03115 518.2016.1132493 Jarzembowski EA, Wang B, Zheng D (2018) A slender new archaic bee- tle in Burmese amber (Coleoptera: Archostemata). Alcheringa: An Australasian Journal of Palaeontology 42: 110-114. https://doi.org/ 10.1080/03115518.2017.1374461 Kirejtshuk AG (2020) Taxonomic review of fossil coleopterous fam- ilies (Insecta, Coleoptera). Suborder Archostemata: superfamilies Coleopseoidea and Cupedoidea. Geosciences 10(2): e73. https://doi. org/10.3390/geosciences 10020073 Li Y-D, Yamamoto S, Huang D-Y, Cai C-Y (2020a) A miniaturized ommatid beetle in mid-Cretaceous Burmese amber (Coleoptera: dez.pensoft.net 308 Archostemata: Ommatidae). Papéis Avulsos de Zoologia 60: €20206063. https://doi.org/10.11606/1807-0205/2020.60.63 Li Y-D, Tihelka E, Yamamoto S, Huang D-Y, Cai C-Y (2020b) A close af- finity of the enigmatic genus Stegocoleus with Lepidomma revealed by new fossil evidence (Coleoptera: Archostemata: Ommatidae). Palaeoentomology 3: 632-640. https://doi.org/10.11646/palaeoen- tomology.3.6.15 Lian X-N, Cai C-Y, Huang D-Y (2021) The early assemblage of Mid- dle—Late Jurassic Yanliao biota: checklist, bibliography and statisti- cal analysis of described taxa from the Daohugou beds and coeval deposits. Palaeoentomology 4: 95-136. https://doi.org/10.11646/ palaeoentomology.4.2.1 Liu Z, Tan J, Slipinski A, Jarzembowski EA, Wang B, Ren D, Pang H (2017) Brochocoleus zhiyuani, a new species of Brochocolein Beetle (Coleoptera: Ommatidae) from the Cretaceous Amber of Myanmar. Annales Zoologici 67: 79-85. https://doi.org/10.3161/0 0034541ANZ2017.67.1.009 McKenna DD, Shin S, Ahrens D, Balke M, Beza-Beza C, Clarke DJ, Donath A, Escalona HE, Friedrich F, Letsch H, Liu S, Maddison D, Mayer C, Misof B, Murin PJ, Niehuis O, Peters RS, Podsiadlowski L, Pohl H, Scully ED, Yan EV, Zhou X, Slipinski A, Beutel RG (2019) The evolution and genomic basis of beetle diversity. Proceedings of the National Academy of Sciences USA 116: 24729-24737. https:// doi.org/10.1073/pnas. 1909655116 Ponomarenko AG (1969) Historical development of archostematan bee- tles. Trudy Paleontologicheskogo Instituta 125: 1-240. [In Russian] dez.pensoft.net Yan-Da Li et al.: Limnomma gen. nov. from Daohugou Ponomarenko AG (1994) New Mesozoic cupedid beetles from Mon- golia. Brochocoleini and Notocupedini. Paleontological Journal 28: 102-115. Ren D (1995) Systematic description of fossils. Insect fossils. In: Ren D, Lu L-W, Guo Z-G, Ji S-A (Eds) Fauna and Stratigraphy of Juras- sic-Cretaceous in Beijing and the Adjacent Areas. Seismic Publish- ing House, Beijing, 47-120. Tan J, Ren D (2009) Mesozoic Archostematan Fauna from China. Science Press, Beijing, 347 pp. [In Chinese with English summary | Tan J, Wang Y, Ren D, Yang X (2012) New fossil species of om- matids (Coleoptera: Archostemata) from the Middle Mesozoic of China illuminating the phylogeny of Ommatidae. BMC Evolu- tionary Biology 12: e113. https://doi.org/10.1186/1471-2148-12- 113 Tihelka E, Huang D, Cai C (2020) New data on Ommatidae (Coleop- tera) from mid-Cretaceous Burmese amber. Cretaceous Research 106: 104253. https://doi.org/10.1016/j.cretres.2019.104253 Yamamoto S (2017) A new genus of Brochocoleini beetle in Upper Cretaceous Burmese amber (Coleoptera: Archostemata: Ommati- dae). Cretaceous Research 76: 34-39. https://doi.org/10.1016/j.cre- tres.2017.04.008 Yang W, Li S (2008) Geochronology and geochemistry of the Mesozoic volcanic rocks in Western Liaoning: Implications for lithospheric thinning of the North China Craton. Lithos 102: 88-117. https://dot. org/10.1016/j.lithos.2007.09.018