Taxonomic revision of the Canthidium Erichson, 1847 species of the gigas group (Coleoptera, Scarabaeidae, Scarabaeinae) Author Carvalho De Santana, Edrielly C. Author Pacheco, Thaynara L. Author Vaz-De, Fernando Z. text European Journal of Taxonomy 2019 2019-06-06 530 1 24 journal article 26523 10.5852/ejt.2019.530 8945f8b0-4be3-4e60-8338-3916fdece1a5 3243046 2CD56144-79D7-4325-BCC6-353C48E374BD Key to the species of the gigas group 1. Head without transverse carina, horn or tubercle along frontoclypeal suture. Cerrado-Atlantic Forest transition in São Paulo state ( Brazil ) ............................. Canthidium (Neocanthidium) ayri sp. nov. – Head with a transverse carina, conical horn or tubercle along the frontoclypeal suture .................. 2 Fig. 1. A . Canthidium gigas Balthasar, 1939 , hypomerum with complete hypomeral carina. B . Canthidium kelleri ( Martínez et al ., 1964 ) , hypomerum with incomplete hypomeral carina. C . Disc of pronotum completely punctated. D . Disc of pronotum with indefinite punctation. Not to scale. Fig. 2. Canthidium gigas Balthasar, 1939 . A . Dorsal view. B . Ventral view. C . Dorsal view of aedeagus. D . Lateral view of aedeagus. Scale bars: 1 mm. 2. Head with conical horn. Hypomeron with incomplete hypomeral carina ( Fig. 1B ). Brazilian Cerrado and neighbouring open area ............... Canthidium ( Neocanthidium ) kelleri ( Martínez et al. , 1964 ) – Head with either short or long transverse carina, lacking a horn. Hypomeron with complete hypomeral carina ( Fig. 1A ). Known from forested/shaded habitats ................................................................... 3 3. Head with a long transverse frontoclypeal carina, length greater than one half interocular width. Pronotum anteriorly with a shallow excavation near centre (absent in small specimens and smaller in females than in males); bordered anteriorly by a transverse bilobed carina (reduced to a pair of lobes in smaller individuals). Amazonia ........................................................................................... 4 – Head with a short transverse frontoclypeal carina, length less than one-third of interocular width. Pronotum convex anteriorly, without evident lobes or excavations. Chaco , Cerrado and Atlantic Forest ................................................................................................................................................ 5 4. Frontoclypeal carina with length less than three-fourths of interocular width. Pronotum with anterior carina and lobes not evident, positioned just behind anterior border and separated from border by distance less than the border width; anterior region of disc punctate, posterior region with indefinite punctation ( Fig. 1D ). French Guiana ............................ Canthidium (Neocanthidium) feeri sp. nov. Fig. 3. Canthidium bokermanni ( Martínez et al ., 1964 ) . A . Dorsal view. B . Lateral view of aedeagus. C . Dorsal view of aedeagus. Scale bars: 1 mm. – Frontoclypeal carina with length greater than four-fifths of interocular width. Pronotum with both anterior carina and two lobes sharply evident, separated from border by a distance equal or greater than the latter’s width; disc with surface completely punctate ( Fig. 1C ). Amazon rainforest south of the Amazon River in Brazil and Peru ........................ Canthidium ( Neocanthidium ) stofeli sp. nov. 5. Parameres, in dorsal view, with strong median angulation and concave apical excavation ( Fig. 2C ); in lateral view, with dorsomedial angulation of 120° ( Fig. 2D ). Brazilian Atlantic Forest, including intrusions into Cerrado ................................... Canthidium ( Neocanthidium ) gigas Balthasar, 1939 – Parameres, in dorsal view, with feeble median angulation and shallow apical excavation ( Fig. 3C ); in lateral view, with dorsomedial angulation of 160° ( Fig. 3B ). Chaco and western Cerrado in Brazil , Bolivia , Paraguay and Argentina ........................................................................................................ .................................................. Canthidium ( Neocanthidium ) bokermanni ( Martínez et al. , 1964 )