Dichotomius (Dichotomius) mormon ( Ljungh, 1799 )

Arias-Buriticá, Jorge Armando & Vaz-de-Mello, Fernando Zagury, 2025, Contributions to the taxonomy of Dichotomius Hope, 1838 (Scarabaeidae: Scarabaeinae: Dichotomiini): Description of a new subgenus and redefinition of Dichotomius sensu stricto species groups, Revista Brasileira de Entomologia (e 20240023) 69 (1), pp. 1-45 : 34

10. Dichotomius (Dichotomius) mormon ( Ljungh, 1799) species group

Diagnosis: This species group was revised by Arias-Buriticá and Vaz-de-Mello (2024b). The species of the D. mormon species group are recognized by the following combination of characters: (1) medium-sized to large-sized individuals (11.4–28.5 mm). (2) Head oval and twice as wide as it is long ( Fig. 19a, b ). (3) Clypeus with two inconspicuous clypeal teeth, sometimes imperceptible ( Fig. 19b ). (4) Ventral clypeal process with triangular appereance with acute or obtuse tip ( Fig. 19c ). (5) Males with lamellar process in the anterior region of head ( Fig. 19a ). (6) Females with conical process in the fronto-clypeal region ( Fig. 19b ). (7) Protibial spur without angle near apex ( Fig. 19d ). (8) Pronotum with strong excavation in the anterior area, pronotal disc with processes 2-6 pointed in males and 2-4 pointed in females ( Fig. 19a, b ). (9) Anterior margin of pronotum behind head with a single lobe ( Fig. 19a ). (10) Elytral striae bicarinate, shallow to distinctly impressed. (11) Pygidium with complete apical margin and evident punctures ( Fig. 19e ). (12). Aedeagus with widened subgenital plate ( Fig. 19h ). (13) Parameres subtriangular in lateral view ( Fig. 19f ), without setae in the apical region ( Fig. 19 f-h). (14) ME well sclerotized, large, and asymmetrical ( Fig. 19l ).

Composition: Five valid species: Dichotomius conicollis (Blanchard, 1846) , D. larseni Arias-Buriticá and Vaz-de-Mello, 2024, D. mormon ( Ljungh, 1799) , D. ohausi ( Luederwaldt, 1923) , and D. talaus ( Erichson, 1847) .

Geographic distribution: Boreal Brazilian dominion (Imerí and Napo provinces), South Brazilian dominion (all provinces), and Paraná dominion (Araucaria, Atlantic, Paraná Forest and Southern Espinhaço provinces) ( Fig. 18b ) .

Figures

Figure 18 a) Distribution map of Dichotomius mamillatus species group. b) Distribution map of Dichotomius mormon species group.

Figure 19 CharacteristicsofDichotomius mormon species group.Dichotomius mormon. Male:a) Dorsal view.c) Ventral clypeal process.d) Protibial spur.e) Pygidium.Aedeagus:f) Lateral view,g) Dorsal view, h) Ventralview.Dichotomius conicollis. Endophallites:i) SRP,j) A+SA complex,k) FLP.l) ME.Female:b) Dorsal view.Scale bars:a-b = 5 mm;c-l = 1 mm.