Diabroctis mimas ( Linnaeus, 1758 )

Rosa, Cecilia Lozano De La, Cupello, Mario & Vaz-De-Mello, Fernando Z., 2024, The dung beetles of Venezuela (Coleoptera: Scarabaeidae: Scarabaeinae): catalogue and updated distribution, European Journal of Taxonomy 959 (1), pp. 1-272 : 219-221

Diabroctis mimas ( Linnaeus, 1758)

Scarabaeus mimas Linnaeus, 1758: 347 (original description). Type locality: South America. Name-bearing type: unknown number of syntypes, unknown whereabouts ( Valois et al. 2018). Linnaeus (1758) assigned to Scarabaeus mimas the specimen illustrated by Rösel von Rosenhof (1749: Scarabaeorum Terrestrium Praef. Classis I, pl. b fig. 1) plus material he studied in the collection of Louisa Ulrika of Prussia, Queen consort of Sweden and a patron of Linnaeus’s. The latter collection was referred to by Linnaeus (1758) through the abbreviation “M.L.U.”, standing for “Museum Ludovicae Ulricae” ( Landin 1956; Maldaner et al. 2017; Hielkema 2022), not “Martin Luther University Halle-Wittenberg”, Germany, as believed by Valois et al. (2018). The Queen’s collection was donated by her grandson, King Gustav IV Adolf of Sweden, to the University of Uppsala in 1803 ( Horn et al. 1990b) and has since been preserved in what is now known as the university’s Museum of Evolution, Zoology Section ( Wallin 2001). Unfortunately, no syntypes of Scarabaeus mimas seem to have survived in the Queen’s collection material ( Landin 1956; Wallin 2001). In spite of that, the specimen illustrated by Rösel von Rosenhof (i.e., one of the syntypes) clearly belongs to the species modernly called Diabroctis mimas and confirms that the allocation of the name has been correct. If desirable, it can be designated as the lectotype. Note that Linnaeus (1758) listed a second literature reference in addition to Rösel von Rosenhof’s work under Scarabaeus mimas : Marcgrave (1648: 247, second figure; the page was erroneously cited as “147”). But because the assignment of this reference to Scarabaeus mimas was doubtful ‒ Linnaeus followed the reference with a question mark and the observation that it might refer to a minor specimen (“Marcgr. bras. 147. f. 2? sed minor”) ‒, Marcgrave’s specimen addressed in it is not part of the type series in accordance with Article 72.4.1 of the Code ( ICZN 1999). This is fortunate, for Linnaeus’s uneasiness was fully justified: the specimen belongs to the species modernly called Coprophanaeus ensifer (Germar, 1821) ( Maldaner et al. 2017) . Later, in the 12 th edition of Systema Naturae, Linnaeus (1767) finally convinced himself of the heterospecificity of the specimens and assigned Marcgrave’s no longer to Scarabaeus mimas , but to his new species Scarabaeus lancifer Linnaeus, 1767 . Nevertheless, because he also assigned to this species individuals belonging to the species modernly called Coprophanaeus lancifer ( Linnaeus, 1767) , this created another nomenclatural problem, one that was only detected and solved 250 years later by Maldaner et al. (2017). Also noteworthy is that, as previously mentioned in the literature ( Landin 1956; Valois et al. 2018) and confirmed by MC during his latest visit in October 2019, the collection of the Linnean Society of London houses a specimen of Diabroctis mimas , but one lacking any labels, let alone one in Linnaeus’s handwriting. This may be a syntype that Linnaeus incorporated into his personal collection, one of the vanished specimens from Queen Louisa Ulrika’ s collection. If this is somehow confirmed ‒ which, alas, due to the apparent lack of any meaningful historical data associated with it, we hardly see happening ‒, the specimen will be, like the one depicted by Rösel von Rosenhof, eligible to become the lectotype.

Distribution

Still ambiguous. The material of D. mimas studied for Valois et al. ’s (2018) review of the genus originates mostly from open environments south of the Amazon Basin in Brazil and Bolivia, as well as from the banks of the lower Amazon, the Marajó Bay and their tributaries ( Valois et al. 2018). The only exception we found in their material examined is an MNRJ male from Rio Uaupés (misspelled by them as “Uapés”), a tributary of the upper Rio Negro, in Brazil’s northwestern Amazon. This might at first indicate that the species was restricted to these two sole countries. Nevertheless, records from all other South American countries except for Ecuador and Chile can be found in the literature (see works cited by Valois et al. 2018; Hielkema & Hielkema 2019). The ones from Paraguay and northwestern Argentina (e.g., d’Olsoufieff 1924; Martínez 1959) are reliable and refer to the same kinds of habitats the species inhabits in Brazil and Bolivia. The one from Peru ( Horgan 2005), though deep into the Amazon, also seems to be correct for no other species potentially present there could be confused with D. mimas . The single record from Uruguay ( d’Olsoufieff 1924), on the other hand, was most likely based on old, mislabelled material and should be incorrect. Similarly, for the Guianas, only old records are available ( Hielkema & Hielkema 2019), and they, too, may well refer to mislabelled specimens. Finally, the Colombian and Venezuelan records (e.g., Vítolo 2000; Medina et al. 2001; references below) may actually refer to Diabroctis venezuelensis , which was recently raised from subspecies status under D. mimas by Valois et al. (2018). Checking the specimens upon which these Venezuelan records were made is necessary to confirm whether the species should be moved to the list of species certainly present in the country or to that of those most certainly absent.

Literature records

Nevinson 1892: 6 ( Venezuela). — Heyne & Taschenberg 1908: 65 ( Venezuela). — Gillet 1911a: 85 ( Venezuela). — d’Olsoufieff 1924: 62, 140 ( Venezuela: Caracas). — Pessôa & Lane 1941: 474

( Venezuela). — Blackwelder 1944: 209 ( Venezuela). — Martínez 1959: 96 ( Venezuela). — Vítolo 2004: 280 ( Venezuela).