Ceratotrupes Jekel, 1865

Arriaga-Jiménez, Alfonsina, Zunino, Mario, Halffter, Gonzalo, Escobar-Hernández, Fernando & Rossini, Michele, 2023, A taxonomic review of the endemic Mexican genus Ceratotrupes Jekel, 1865 (Coleoptera: Geotrupidae: Ceratotrupini), with the description of an unexpected new species from the Sierra Madre del Sur, European Journal of Taxonomy 885, pp. 1-20 : 16-17

Identification key to the species of the genus Ceratotrupes Jekel, 1865

1. Anterior half of lateral edges of pronotum curved ........................................................................... 2

– Anterior half of lateral edges of pronotum straight and convergent ................................................. 3

2. Anterior angles of pronotum of male evenly curved; outer surface of the first antennomere of antennal club with a deep elliptical groove ( Fig. 2C ); middle and posterior trochanters densely and clearly punctate ....................................................................... C. bolivari Halffter & Martínez, 1962

– Anterior angles of pronotum of male obtusely squared; outer surface of the first antennomer of antennal club either without or with a feeble groove; middle and posterior trochanters with scattered punctures ......................................................................................... C. fronticornis ( Erichson, 1847)

3. Posteromedial edge of pronotum without margin ( Fig. 4C ); clypeal horn strong, as large as one third the distance between inner margin of eyes, tip medially depressed ( Fig. 4A, C ); anteromedial pronotal projection with parallel sides ( Fig. 4A, D ), apically almost as large as half the distance between inner margin of eyes, apical edge widely depressed, with lateral protrusions distant; elytral interstriae very finely and densely punctate ........................................................ C. gonzaloi sp. nov.

– Posteromedial edge of pronotum margined ( Fig. 3C ); clypeal horn thin, as large as one fifth of the distance between inner margin of eyes, tip medially not depressed, narrow and blunt ( Fig. 3A, C ); anteromedial pronotal projection with convergent sides, apically almost as large as one third of the distance between inner margin of eyes, apical edge very narrowly depressed, with lateral protrusions very close; elytral interstriae unpunctured ................................... C. sturmi ( Jekel 1865)

Figures

Fig. 2. Ceratotrupes bolivari Halffter & Martínez, 1962 (CMNC). A–B. Dorsal habitus of male (A) and female (B). C. Detail of the elliptical groove of the last antennal lamella. D–E. Aedeagus in dorsal (D) and lateral view (E).

Fig. 4. Ceratotrupes gonzaloi sp. nov. (CMNC). A–B. Dorsal habitus of male (A) and female (B). C. Details of head and prothorax; arrows indicate posteromedial edge of pronotum without margin. D. Details of cephalic horn and pronotal projection of male. E. Aedeagus in dorsal view. F. Parameres in dorsal view; arrows indicate main differences between C. gonzaloi sp. nov. and C. sturmi. G. Right paramere in lateral view; arrow indicates absence of lobe beneath apical spur.H. Tergite.I. Pleurotergites. J. Phallobase in ventral view; arrow indicates straight margin of ventral lobe. K. Phallobase in dorsal view. L. Phallobase in lateral view; arrow indicates the short bifurcation. M. Internal sac (is) and median struts (ms) in dorsal view. N. Internal sac and median struts in lateral view.

Fig. 3. Ceratotrupes sturmi (Jekel, 1865) (CMNC). A–B. Dorsal habitus of male (A) and female (B). C. Details of head and prothorax; arrows indicate posteromedial edge of pronotum margined. D. Details of cephalic horn and pronotal projection of male. E. Aedeagus in dorsal view. F. Parameres in dorsal view; arrows indicate main differences between C. sturmi and C. gonzaloi sp. nov. G. Right paramere in lateral view; arrow indicates lobe beneath apical spur. H. Tergite. I. Pleurotergites. J. Phallobase in ventral view; arrow indicates curved margin of ventral lobe. K. Phallobase in dorsal view. L. Phallobase in lateral view; arrow indicates long bifurcation. M. Internal sac (is) and median struts (ms) in dorsal view. N. Internal sac and median struts in lateral view.