Zootaxa 4083 (3): 431–443 ISSN 1175-5326 (print edition) http://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2016 Magnolia Press ISSN 1175-5334 (online edition) http://doi.org/10.11646/zootaxa.4083.3.7 http://zoobank.org/urn:lsid:zoobank.org:pub:C999EBFD-4EAF-44E1-B7E9-95C9C63E556B Blind life in the Baltic amber forests: description of an eyeless species of the ground beetle genus Trechus Clairville, 1806 (Coleoptera: Carabidae: Trechini) JOACHIM SCHMIDT1, 2, HANNES HOFFMANN3 & PETER MICHALIK3 1University of Rostock, Institute of Biosciences, General and Systematic Zoology, Universitätsplatz 2, 18055 Rostock, Germany 2Lindenstraße 3a, 18211 Admannshagen, Germany. E-mail:
[email protected] 3Zoological Institute and Museum, Ernst-Moritz-Arndt-University, Loitzer Str. 26, D-17489 Greifswald, Germany. E-mail:
[email protected] Abstract The first eyeless beetle known from Baltic amber, Trechus eoanophthalmus sp. n., is described and imaged using light microscopy and X-ray micro-computed tomography. Based on external characters, the new species is most similar to spe- cies of the Palaearctic Trechus sensu stricto clade and seems to be closely related to the Baltic amber fossil T. balticus Schmidt & Faille, 2015. Due to the poor conservation of the internal parts of the body, no information on the genital char- acters can be provided. Therefore, the systematic position of this fossil within the megadiverse genus Trechus remains dubious. The occurrence of the blind and flightless T. eoanophthalmus sp. n. in the Baltic amber forests supports a previ- ous hypothesis that these forests were located in an area partly characterised by mountainous habitats with temperate cli- matic conditions.