New finding of Toxorhina (Ceratocheilus) limoniid fly in Eocene Baltic amber and the biogeographical context of the genus

Abstract

Based on new fossil materials, a new species Toxorhina (Ceratocheilus) christelius sp. nov. has been described herein with complete documentation of drawings and photographs. Features such as wide spine on the gonocoxite differentiating the new species of Toxorhina were discussed. Finding new interesting fossil materials also allowed for providing an emended diagnosis and additional description of known Eocene species—Toxorhina (Ceratocheilus) eridanus. Comparison of chosen morphological features of fossil and recent representatives of the genus were given and key for fossil species of subgenus Ceratocheilus was introduced. Distribution of recent Toxorhina and evolutionary history of the genus were discussed. The results of research on fossil materials prove that the stratigraphic range of the subgenus Ceratocheilus and the genus Toxorhina goes back to the Eocene, there is no evidence of their existence on Earth before. Moreover, these insects were probably associated with a warm climate, they were found for example in Baltic amber, the deposits of which were formed mainly in a subtropical climate. The reach diversity of the genus Toxorhina of recent fauna is strictly observed in tropical zones around the world.