Deltepilissus diabolicus
Creators: name: Silva, Fernando A. B.
name: Ferreira, Ana B. M.
name: Génier, François
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Deltepilissus
Deltepilissus diabolicus

description: Deltepilissus diabolicus (Harold, 1880)
(Figs 1A–I, 3A–C, 3G, 3I, 3K, 3M, 4A–B, 5A–B)
Canthon diabolicus Harold 1880: 150 (original description); Gillet 1911: 29 (catalog); Schmidt 1922: 67, 74 (taxonomic remarks, distribution); Balthasar 1939: 201 (identification key); Blackwelder 1944: 199 (checklist); Vulcano & Pereira 1964: 611 (catalog).
Deltepilissus diabolicus: Halffter & Martínez 1977: 66 (transferred C. diabolicus to the genus Deltepilissus, checklist); Vaz-de-Mello 2000: 192 (checklist); Krajcik 2006: 47 (checklist); Krajcik 2012: 88 (checklist); Schoolmeesters 2020 (catalog); Vaz-de-Mello 2021 (checklist).
Diagnosis. Deltepilissus diabolicus can be distinguished from D. infernalis by the head approximately 1.2 times wider than long (Fig. 1C); punctures of central portion of pronotum closely set, spaced by less than their diameter (Fig. 1A); body length about 15 mm. Furthermore, males have wide and rounded protibial spur, lacking denticle apically (Fig. 1G); and rounded metatibial spur apically, with almost inconspicuous inner denticle (Fig. 1H). Apex of parameres are also distinctly curved inward in dorsal and ventral views (Figs 3A–B).
Redescription. Colour and tegument sculpture (Figs 1A–B). Body, in general, black. Head and pronotum with light copper or green sheen. Body surface densely punctate. Length. 15 mm. Head (Fig. 1C). Densely punctate. Foveiform punctures approximately equally spaced to their diameter; punctures around clypeal teeth shallower, more spaced and smaller. Clypeus with two widely spaced, small teeth. Surface slightly depressed behind clypeal teeth. Clypeo-genal suture visible. Thorax. Disc of pronotum with dense closely set foveiform punctures, approximately spaced by less than their diameter; punctures denser on posterocentral portion (Fig. 1A). Hypomera not excavate, with sparse setose punctures on anterior and posterolateral portions (Fig. 1D). Hypomera with oblique carina not reaching lateral margin; carina about half hypomeral width. Mesoventrite almost smooth, with sparse punctures. Metaventrite punctures variable in size, smaller and denser medially (Fig. 1B). Elytra (Fig. 1A). Punctures of elytral striae spaced by once or twice their diameter on 1st, 2nd and 3rd striae; punctures more spaced on lateral striae. Elytral striae wider, carinate margins clearly separated. Seventh stria effaced basally. Eighth and ninth striae almost fused, only visible on posterior half. Elytral interstriae with dense, close and foveiform punctures, generally spaced by less than their diameter. Pseudepipleural carina complete, visible on entire length of epipleuron. Abdomen (Fig. 1E). Punctures denser on lateral surface of ventrites. Pygidium rounded apically, densely punctate, separated from propygidium by carina (Fig. 1F). Pygidium with sulcus on basal and apical edges (Fig. 1F). Legs. Metatibial spur spatulate, with lateral edges weakly sinuous; apex rounded, with inconspicuous inner denticle (Fig 1H). First meso- and metatarsomeres triangular; tarsomeres 2–4 trapezoidal, apical tarsomere subrectangular (Fig 1H). Tarsal claws reduced (Figs 1G–I). Sexual dimorphism. Females can be distinguished from males by last abdominal ventrite evenly wide. Last abdominal ventrite of males subtly narrower medially. Females with protibial spur slightly emarginate apically (bifurcate). Protibial spur of males wide and rounded, lacking denticle apically (Fig. 1G). Females with metatibial spur apically sinuous and bifurcate, with denticle (spiniform process) on internal and external edges (Fig. 1I). Males with metatibial spur rounded apically, inner denticle almost inconspicuous (Fig. 1H). Apical third of metatibiae almost straight in females (Fig. 1I), distinctly curved inward in males (Fig. 1H).
Aedeagus. Parameres symmetrical, subparallel in lateral view, with abruptly pointing downward apically (Fig. 3C). Apex of parameres curved inward in dorsal and ventral views (Figs 3A–B). Endophallus. Lamella copulatrix absent. Superior right peripheral endophallite ring shaped; lateral projection arched, rounded apically (Fig. 3G). frontolateral peripheral endophallite elongate, irregular (Fig. 3I). Complex of axial and subaxial endophallites elongate, irregular (Fig. 3M). Additional endophallites short, comma shaped (Fig. 3K).
Type material. Canthon diabolicus Harold. Lectotype ♀ (here designated; MFNB) (Figs 4A–B): “ HOLOTYPE // Bahia, / Sello // 9004 // Type // diabolicus / Har // SYNTYPUS / Canthon / diabolicus Harold, 1880 / labelled by MNHUB 2013”
Additional material. BRAZIL: BAHIA, no date and collector – 1 sex undetermined (BMNH – ex Fry collection); Ilhéus, 11.IX.1968, Guy V. Santos – 1 ♂ (CEMT).
Habitat. Most likely from Atlantic coastal rainforest. The type specimen of D. diabolicus was collected by the Prussian naturalist Friedrich Sellow (1789–1831). He travelled through Brazil, Uruguay and Argentina between 1814 and 1831. We were able to check Sellow’s itinerary in Bahia (Papavero 1971, map 8). Therein, he only visited areas in the Atlantic coastal forest between Salvador and southern Bahia. Furthermore, the only specimen studied here with a precise locality was collected from Ilhéus, which is a coastal city located in southern Bahia. The predominant ecosystem surrounding the area is the Atlantic coastal forest, which hosts a high number of endemic species. In addition to this vegetation, there are areas of restinga (tropical rainforest close to coastal, sandy areas) and mangroves on the coastal line, and large cocoa-growing areas planted among the natural Atlantic rainforest (Cabruca = ecological system of cultivation agroforestry). The specimen might have been collected from any of these different habitats.
Distribution. Known only from Brazil (Bahia). Literature records. BRAZIL: Bahia (Harold 1880) (Fig. 5).
Conservation status. Based on available data, this species seems to be endemic to the state of Bahia, Brazil. The last known record for this species was from Ilhéus in 1968. Therefore, we do not have information about the conservation status of populations of this species. We know at least two cases of apparently rare species along the range of the two species of Deltepilissus (southern Bahia and Espírito Santo) that when the number of collectors in the area increased, a great number of specimens have been collected. These cases can be verified with Streblopus opatroides Van Lansberge, 1874 (Cupello et al. 2020) and some species of Aphengium Harold, 1868 (Silva & Vaz-de-Mello 2015). However, despite many collecting efforts with pitfalls and/or flight interception traps in Atlantic rainforest remnants throughout that region and neighboring areas (F. Silva and F. Vaz-de-Mello, personal communication) no specimens of D. diabolicus have been recently collected. The rarity of D. diabolicus in natural history collections can be due to its unknown natural history and/or some unusual ecological specialization. The baits used for collecting ‒ usually, human feces ‒ might not be attractive for this species. Even so, flight interception traps would have likely collected specimens were the populations substantial, suggesting that population densities are indeed quite low or that the specimens flying higher in the canopy.
Based on its supposed endemicity, the extent of occurrence of this species is being estimated as up to 100 km 2, with large surrounding areas of unsuitable habitat. The Atlantic rainforest is probably the most extinction-prone ecosystem of Brazil. Its ecosystems have been suffering intense degradation early during European colonization. The major threats for the southern Bahia region are urbanization (residential and industrial development), illegal wood exploitation, and impacts associated with tourism (Vieira et al. 2011; Silva et al. 2020). Therefore, we evaluated this species using the International Union for Conservation of Nature (2012) criteria and found that it could be assessed as Critically Endangered (CR) under criterion B1ab(iii)+B2ab(iii), mainly due to high fragmentation and destruction of the Atlantic rainforest, and its apparent restricted distributional range, and also due to the low number of individuals historically collected. Sellow died in 1831 (Papavero 1971), therefore the specimen studied by Harold was certainly collected at least 190 years ago, and after that date few specimens were recorded.
description: Published as part of Silva, Fernando A. B., Ferreira, Ana B. M. & Génier, François, 2022, Taxonomic revision of the genus Deltepilissus Pereira, 1949 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), pp. 83-96 in Zootaxa 5120 (1) on pages 87-89, DOI: 10.11646/zootaxa.5120.1.5, http://zenodo.org/record/6388909