Reference
Sergio Perez-Gonzalez, Juan P. Zaballos (2019): Structure of male genitalia in a lineage of minute endogean ground beetles: how four new species of Microcharidius Coiffait, 1969 (Coleoptera: Carabidae: Anillini) reveal gradual change and convergent evolution – Arthropod Systematics and Phylogeny – 77: 57 - 86.