Taxonomic notes on the ground beetles in the genus Trephionus Bates, 1883 from central Honshu, Japan (Coleoptera, Carabidae, Sphodrini, Synuchina).

Kôji Sasakawa,Hirotarô Itô

doi:10.3897/zookeys.742.23752

Abstract

Trephionus Bates, 1883, a Japanese endemic genus in the subtribe Synuchina (Coleoptera, Carabidae, Sphodrini), is revised taxonomically based mainly on the shape of the endophallus, a membranous inner sac everted from the aedeagus of the male genitalia. Three known species from central Honshu, T. kinoshitai Habu, 1954; T. shibataianus Habu, 1978; and T. babai Habu, 1978, are re-defined based on this genital character, and five new species are described from the region: T. cylindriphallus Sasakawa, sp. n., T. niumontanus Sasakawa, sp. n., T. inexpectatus Sasakawa & Itô, sp. n., T. abiba Sasakawa & Itô, sp. n., and T. bifidilobatus Sasakawa & Itô, sp. n. The observed interspecies differences in endophallus morphology are discussed in terms of the species-level phylogeny and genus-level taxonomy of Trephionus.

Highlights

Trephionus Bates, 1883 is a Japanese endemic genus in the subtribe Synuchina (Coleoptera, Carabidae, Sphodrini) that is distributed in Honshu, Shikoku, and Kyushu (Lindroth 1956; Habu 1978; Casale 1998)
This study revealed that Trephionus has diversified in terms of the male endophallus and there are “cryptic species” that can be distinguished only by the endophallus
These findings indicate the need for re-definition of the known Trephionus species based on this genital morphology

Summary

Introduction

Trephionus Bates, 1883 is a Japanese endemic genus in the subtribe Synuchina (Coleoptera, Carabidae, Sphodrini) that is distributed in Honshu, Shikoku, and Kyushu (Lindroth 1956; Habu 1978; Casale 1998). In Carabidae, the taxonomic utility of the shape of the endophallus, a membranous inner sac everted from the aedeagus of the male genitalia, has been demonstrated in studies of various taxa during the last decade. These studies showed that the morphology of the endophallus can provide useful taxonomic information that cannot be obtained from external or other genital morphology. The implications of these results for the species-level phylogeny and genus-level taxonomy of Trephionus are discussed

Materials and methods

Discussion