On the Nosodendridae from mid-Cretaceous amber of northern Myanmar (Coleoptera: Nosodendroidea) Author Li, Yan-Da 0000-0002-9439-202X State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China ydli@pku.edu.cn Author Tihelka, Erik 0000-0002-5048-5355 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China & School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS 8 1 TQ, UK & wn 20250 @ bristol. ac. uk; https: // orcid. org / 0000 - 0002 - 5048 - 5355 wn20250@bristol.ac.uk Author Dahan, Loïc 0000-0001-5680-0304 O. D. Taxonomy and Phylogeny - Entomology, Royal Belgian Institute of Natural Sciences, Vautierstreet 29, B- 1000 Brussels, Belgium ydli @ pku. edu. cn; https: // orcid. org / 0000 - 0002 - 9439 - 202 X & loicdahan @ hotmail. com; https: // orcid. org / 0000 - 0001 - 5680 - 0304 loicdahan@hotmail.com Author Huang, Di-Ying 0000-0002-5637-4867 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China & dyhuang @ nigpas. ac. cn; https: // orcid. org / 0000 - 0002 - 5637 - 4867 dyhuang@nigpas.ac.cn Author Cai, Chen-Yang 0000-0002-9283-8323 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China & School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS 8 1 TQ, UK & cycai @ nigpas. ac. cn; https: // orcid. org / 0000 - 0002 - 9283 - 8323 cycai@nigpas.ac.cn text Zootaxa 2021 2021-12-17 5082 3 223 244 journal article 2910 10.11646/zootaxa.5082.3.2 3997d831-ae29-42d0-ba99-cd20cc8b7fc3 1175-5326 5788224 EFB0E4A5-6B60-4B39-A651-1C6470FD7222 Genus Basinosa Tihelka, Huang & Cai, 2020 ( Figs 15 , 16 ) Type species. Basinosa pengweii Tihelka, Huang & Cai, 2020 . Material examined. Holotype of B. pengweii , NIGP 173119. Remarks. The amber piece containing the holotype of B. pengweii is somewhat nontransparent, making it difficult to determine many of the characters using normal optical methods. Partly due to tomographic artefacts, some characters were not clearly visualized in previous micro-CT reconstructions. For example, one of the key diagnostic characters for Nosodendridae , the 11-segmented antenna with 3-segmented club, could not be observed in Tihelka et al. (2021a) , although other diagnostic characters could be confirmed. Here we reexamine the original CT data for the holotype of B. pengweii . It turns out that the majority of the beetle body has high absorption (white), while the antennae (especially the left one) appear to have lower absorption (black) ( Fig. 16A ). Therefore, the antennae were not properly reconstructed in the simple reconstruction, where only regions with a density higher than a selected threshold were extracted. Confocal microscopy confirms the 3-segmented club of B. pengweii ( Fig. 16C ). Since the strong laser could penetrate the somewhat opaque amber matrix better, and out-of-focus light is blocked, the confocal microscope could image this material much better than widefield ones ( Fu et al. 2021 ). The medial antennomeres of B. pengweii appears to be relative elongate ( Fig. 16B ), while in extant Nosodendron the medial antennomeres are almost as long as wide. Confocal microscopy additionally reveals that the prosternal process ( Fig. 16E ) is not as slender as shown in the CT reconstruction by Tihelka et al. (2021a) , which was subsequently adopted as one of the characters differentiating Basinosa from Mesonosa (Tihelka et al. 2020b) . Detecting the boundaries of structures under CT is a challenging task ( Coleman & Colbert 2007 ); the boundaries between the beetle and the amber matrix are not clearly defined, but are instead represented by a continuum of transitional values. Thus, a different selection of the threshold value for extraction could sometimes greatly affect the visual appearance. The 3-segmented antennal club, together with the previously shown subantennal groove, wide metaventrite, clearly delimited anterolateral depression of metaventrite for the reception of mesotibial apex and basal mesotarsomeres, and narrowly separated metacoxae (all present in extant Nosodendridae and fossil Nosodendridae from the Burmese amber; fig. 23C in Ge et al. 2007), further confirm the placement of Basinosa in Nosodendridae . Basinosa is unique in Nosodendridae in having a relatively large body and complete antennal grooves on prosternum.