New distribution records from Turkey: A checklist of earthworm species (Oligochaeta, Lumbricidae) from Akdag (Kutahya) with records of some endemic, peregrine taxa and other faunal elements

This study presents a list of earthworm species distributed in the Akdag region, located within the boundaries of the Simav district of Kutahya in northwestern Turkey, and provides new distribution records for some species belonging to the fauna of Turkey. The aim of the study is to contribute to the body of knowledge on the geographic distribution of Turkey’s earthworm fauna. In this context, a soil earthworm inventory was conducted at 118 sampling points in May 2018, and a total of 447 earthworm specimens were collected. As a result of taxonomic studies, six genera and 11 taxa belonging to the Lumbricidae family were identified. Three of these taxa are endemic (Dendrobaena nivalis, Spermophorodrilus vignai and Spermophorodrilus simsoni), one is a Trans-Aegean element (Proctodrilus tuberculatus), one is a Mediterranean element (Dendrobaena byblica), two are Caucasus-Anatolian elements (D. schmidti tellermanica, D. pentheri), and four are peregrine (Octolasion lacteum, Aporrectodea rosea, A. caliginosa, Bimastos rubidus). The species Dendrobaena byblica, Bimastos rubidus, Dendrobaena schmidti tellermanica, and Spermophorodrilus simsoni have been reported for the first time in the Kutahya region. This data indicates that Kutahya is a new distribution area for these taxa. The coexistence of endemics, faunal elements and peregrine species highlights Akdag’s significance as a biogeographic transition zone. Furthermore, the presence of taxa with diverse geographical origins indicates that earthworm communities in Akdag harbor significant ecological and functional diversity. These findings contribute significantly to the understanding of earthworm biogeography in Turkey. Furthermore, the simultaneous presence of endemics, faunal elements and peregrine species highlights their critical roles in shaping regional earthworm communities and provides a basis for future ecological and conservation-oriented studies.