Chalcoderus signatipennis (de Castelnau, 1840), restored status, restored combination(Fig. 3)Onthophagus signatipennis de Castelnau, 1840: 85 (described from Senegal).“Onthoph. signatipennis Dej. Lap. ” (Erichson 1847: 763) (citation).Chalcoderus signatipennis Laporte (Erichson 1847: 763) (change of genus).O[nthophagus] signatipennis Casteln. (Lacordaire 1855: 109 (note 3)) (citation).Onthophagus signatipennis Casteln. (Harold 1869: 1032) (synonymy with O. maculatus Fabr.).Onthophagus maculatus Fabricius (d’Orbigny 1905a: 450) (comparison with “ O. chloroderus n. sp. ”—Starting point of the confusion).Onthophagus maculatus Fabricius, 1801 (d’Orbigny 1913: 257–258) (citation consistent with earlier synonymy of O. signatipennis).Onthophagus maculatus Fabricius (d’Orbigny 1914: 656) (catalogue).Onthophagus signatipennis Castelnau (d’Orbigny 1914: 657) (citation as synonym of O. maculatus Fabr.).Onthophagus maculatus F. 1801 (Boucomont & Gillet 1927: 180) (citation sensu d’Orbigny 1913).Onthophagus signatipennis Cast. (Boucomont & Gillet 1927: 180) (citation as synonym of O. maculatus F. sensu d’Orbigny).Parascatonomus (Morettoeus) maculatus (Fabricius, 1801) (Ochi & Kon 2023: 579 (transfer to Parascatonomus (Morettoeus)).All citations of Onthophagus maculatus published subsequent to Onthophagus maculatus sensu d’Orbigny (1905a: 450) relate to Chalcoderus signatipennis de Castelnau, 1840 (see summary below).The type material is presumed destroyed (Evenhuis 2012). Here, we designate a neotype ♂ selected from specimens held in the MNHN: “ SENEGAL / FORET DE BANDIA // Museum Paris / Collection générale // Neotype ♂ / Onthophagus / signatipennis / de Castelnau, 1840 / Moretto, Deschodt / & Davis des. 2025 {handwritten on red label} // Chalcoderus signatipennis / (de Castelnau 1840) / Moretto, Deschodt & Davis / det. 2025” (MNHN).Type locality (Article 76.3): Sénégal, Région de Thies, Forêt de Bandia. The “Forêt de Bandia” corresponds to the current private “Réserve de Bandia” (14° 36′ N, 16° 57′ W).Original description (de Castelnau 1840): “17. Onthophagus signatipennis. Long. 4 lig. ½. Larg. 2 lig. ½. — D’un rouge cuivreux; corselet très-bombé, entièrement granuleux; élytres d’un brun jaune, striées, avec deux bandes transversales irrégulières, noires, formées de taches qui se réunissent ordinairement: elles offrent aussi chacune une tache noire vers l’extrémité; dessous du corps et pattes d’un vert cuivreux. — Sénégal.”From this description, it is clear that Onthophagus signatipennis de Castelnau, 1840, corresponds to what d’Orbigny (1913) believed to be Ateuchus maculatus Fabricius, 1801. It is here removed from synonymy with Ateuchus maculatus Fabricius, 1801 and its valid species status is restored. As Erichson (1847) described the genus Chalcoderus for both Ateuchus maculatus Fabricius, 1801, and Onthophagus signatipennis de Castelnau, 1840 (cited as At. maculatus F., Onthoph. signatipennis Dej. Lap.), the combination Chalcoderus signatipennis (de Castelnau, 1840) is, therefore, restored.Distribution of C. signatipennis (Fig. 4) according to studied specimens: Gambia, Guinea Bissau and Senegal west of the Senegal River, plus mostly on Tertiary sediments of the Senegalese Basin (Thieblemont et al. 2016); Western Mali (“Haut Sénégal, Khayes” PMOC).To summarize, Onthophagus maculatus sensu d’Orbigny (1913: 257–258) is actually Chalcoderus signatipennis (de Castelnau, 1840) whereas Onthophagus chloroderus d’Orbigny, 1905 (1905a: 450; 1913: 258) is actually Chalcoderus maculatus (Fabricius, 1801). The descriptions given by d’Orbigny (1913: 257–258) are precise and allow the two species to be easily separated. Subsequent erroneous citations with respect to these inversions have extended to the present day and it is appropriate to interpret nomenclature in these subsequent publications accordingly, including Ochi & Kon (2023, Figs 1a–j and 2a–d).