X-ray microscopy reveals endophallic structures in a new species of the ground beetle genus Trechus Clairville, 1806 from Baltic amber (Coleoptera, Carabidae, Trechini)

Joachim Schmidt; Igor Belousov; Peter Michalik

doi:10.3897/zookeys.614.9283

X-ray microscopy reveals endophallic structures in a new species of the ground beetle genus Trechus Clairville, 1806 from Baltic amber (Coleoptera, Carabidae, Trechini)

Zookeys. 2016 Sep 1:(614):113-27. doi: 10.3897/zookeys.614.9283. eCollection 2016.

Authors

Joachim Schmidt¹, Igor Belousov², Peter Michalik³

Affiliations

¹ University of Rostock, Institute of Biosciences, General and Systematic Zoology, Universitätsplatz 2, 18055 Rostock, Germany; Lindenstraße 3a, 18211 Admannshagen, Germany.
² All-Russian Institute of Plant Protection, 3, Podbelsky shosse, 196608 St. Petersburg, Russia.
³ Zoological Institute and Museum, Ernst-Moritz-Arndt-University, Loitzer Str. 26, 17489 Greifswald, Germany.

Abstract

The third fossil species of the genus Trechus Clairville, 1806 is described from Baltic amber: Trechus exhibitorius sp. n. Details of external and internal morphology were analysed using X-ray micro-computed tomography (micro-CT) and important diagnostic features of the internal male genital sac (endophallus) are described in detail for the first time in a fossil ground beetle. Based on these data, we could assign Trechus exhibitorius sp. n. to Trechus sensu stricto and this new fossil species seems to represent a basal branch of a lineage comprising species diverse groups of extant Trechus mainly distributed in the Caucasus and Anatolia. Thus, our results support previous studies suggesting that Trechus is a phylogenetically old lineage already present in the Eocene with numerous species.

Keywords: 3-D reconstruction; Eocene; micro-CT.