Bothynus cylindricus Arrow 1937
Creators: name: Duarte, Paulo R. M.
name: Dupuis, Fabien
name: Grossi, Paschoal C.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Bothynus
Bothynus cylindricus

description: Bothynus cylindricus Arrow, 1937a
(Figures 2 (d), 3(e), 8(b), 9(c,d), 11(c,d), 13(e,s), 14(e), 15(f), 16(h), 18(c), 21(b), 22)
Bothynus cylindricus
Arrow 1937a: 45 (original description); Arrow 1937b: 40 (catalogue); Blackwelder 1944: 244 (checklist); Endrödi 1969: 113 (identification key), 117 (illustration of the aedeagus [figs. 165–167]), 135 (diagnosis, distribution); Endrödi 1985: 276 (illustration of the aedeagus [figs. 1132–133], identification key, distribution). Krajcik 2005: 38 (checklist); Abadie et al. 2008, pl. 13 (dorsal habitus [Figure 5], distribution). López-García et al. 2016: 496 (checklist).
Diagnosis
Bothynus cylindricus resembles B. laticifex but the former is distinguished by the following combination of characters: Posterior region of the prontal concavity interrupted at middle (Figure 9 (c)); posterior corners of the male pronotum strongly rugopunctate or rugose (Figure 9 (d)); inner protarsal claw of male with elongated outer branch, surpassing the basal half of the inner one in length (Figure 11 (c)); dorsal surface of parameres covered with well-impressed punctures (Figure 13 (e)); basal sides of parameres with constricted sides in frontal view (Figure 13 (s)). Bothynus cylindricus also can be confused with minor specimens of B. ascanius, but B. cylindricus can be separated by the following characters: Interocular width about 4.1–4.4 transverse eye diameter in both sexes; male pronotum with cavity interrupted at middle of posterior edge (Figure 9 (c)) in both sexes; large and dense punctures on the sides of male pronotum (Figure 9 (c, d)); spiculum gastrale with subequal branches (Figure 12 (c)).
Type material
Lectotype male, here designated, labelled: (a) ‘ SYN- /TYPE’ [rounded label, bordered in blue]; (b) ‘Type’ [rounded label, bordered in red]; (c) ‘Minas/Brasil’ [handwritten]; (d) ‘67.45’ [handwritten]; (e) ‘686’. [handwritten]; (f) ‘Columbus/[illegible]/Brasilia’ [handwritten]; (g) Bothynus / cylindricus /type arrow” [handwritten] (NHM) (Figure 2 (d)). Paralectotype female, here designated, labelled: (a) ‘SYN/TYPE’ [rounded label, bordered in blue]; (b) ‘Fry/Rio Jan’. [handwritten]; (c) ‘Fry. Coll/1905.100’. [handwritten] (NHM).
Additional material
ARGENTINA: Misiones: 22.i.1995, R. Foester leg. – 1 male (CERPE). BRAZIL: Distrito Federal: Brasília, Embrapa HortaliÇas, 3–8.xi.2016, N. G. Souza leg. – 1 male (CERPE). Goiás: Cristalina, Fazenda Larga Grande, 30.i.2017 / 3–8.xi.2017, luz, N. G. Souza leg. – 2 females (CERPE); Planaltina, Embrapa Cerrado, 26.vii.2005, C. Oliveira leg. – 1 male (CEMT). Minas Gerais: Lavras, 05.viii.1999, M. Sampaio leg. – 1 male (CERPE); Lavras, 19.viii.2006, luz, G.A. Souza leg. – 1 female (CERPE). São Paulo: Lins, Fazenda Santa Clara, 19.ix.1981, luz, L. Evandro leg. – 1 male (CEMT). Rio Grande do Sul: Frederico Westphalen, Vila Faguense, 14.i.2005, Sponchiado, V.E.C. – 1 male (CEMT).
Male redescription (Figure 3 (e))
Length: 19.0–20.0 mm. Width: 10.6–11.0 mm. Colour: Reddish brown in overall aspect; pronotum, meso- and metatibia sometimes dark reddish brown. Head: Clypeus subtriangular (posterior width about 3.2–3.8 times wider than anterior); lateral margins evenly convergent; anterior teeth from subtriangular to lobed, usually with rounded apex; surface glabrous, strongly rugose. Frontoclypeal carina well marked, slightly arched in frontal view. Frons strongly rugose, bearing minute punctures between wrinkles; setae scarce, arranged on sides; discal area glabrous; interocular width equals 4.1–4.4 transverse eye diameters. Ocular canthus transverse, usually subrectangular, bearing arched anterior margin. Mouthparts: Mandible with apical and medial teeth subtriangular, basal tooth lobed; apical tooth diagonally truncated on apex. Labium subtriangular, slightly rounded laterally; sides setose, disc weakly rugose. Prothorax: Pronotum with anterior tubercle small, conical, rounded apically; cavity small, rounded, shallow confined on anterior disc (Figure 8 (b)); posterior limit of cavity interrupted at middle in laterodorsal view (Figure 9 (c)); pronotal sides with dense, large, contiguous punctures, coalescent near margins; posterior disc with minute punctures; transverse area close to posterior margin from rugopunctate to rugose (Figure 9 (d)); cavity nearly entirely rugose, except for the posterior limit covered with large, transverse, C-shaped punctures. Pterothorax: Elytral surface with well-marked striae, covered with small, ocellate punctures; punctures contiguous on sutural stria, from contiguous to 1 puncture diameter apart on other striae; interstriae with minute punctures. Legs: Inner protarsal bent downward nearly 90° (Figure 11 (d); outer branch acute, elongated, surpassing the basal half of the inner one in length (Figure 11 (c)); inner branch broader compared to outer one. Protarsomere 5 bearing a triangular, subapical, ventral process. Mesofemora with glabrous ventral disc. Meso- and metatibiae only with a middle carina. Abdomen: Tergite 7 with stridulatory apparatus formed by 1 band of numerous finely marked, transverse striae. Tergite 8 glabrous, rugose on sides and a transverse area close to anterior margin, disc with shallow, transverse punctures. Sternites 4–7 with moderately punctate and weakly setose sides, discal area smooth; sternite 8 bearing smooth disc, sides weakly rugopunctate. Spiculum gastrale: Y-shaped; branches subequal in length; medial branch narrow at basis (Figure 12 (c)). Hemisternite in shape of an inverted, transverse triangle; apical margin bearing 5–7 setae on apical margin. Aedeagus: Parameres, in caudal view, rugopunctate; basal half rhomboid-shaped; apical half strongly constricted lateroventrally; apical lobes broad rounded (Figure 13 (e)). Parameres, in frontal view, with narrow basal sides (Figure 13 (m)). Parameres, in lateral view (Figure 14 (e)), ventrally with a small carina at basis; apex weakly deflexed; subapical area behind lobe strongly depressed.
Female description (Figure 15 (f))
Length: 19.0– 19.2 mm. Width: 10.8–11.0 mm. As for the male, except for the following aspects: Prothorax: Pronotal surface nearly entirely covered with dense, large, deep, ocellate punctures; punctures on posterior sides separated by about 1–2 puncture diameters; tubercle very small or obsolete; cavity shallow. Legs: Inner protarsal claw simple, similar to outer claw. Tarsomere 5 with no ventral process. Abdomen: Sternite 8 nearly entirely rugose, with moderated setae transversely arranged (Figure 21 (b)).
Distribution
Argentina (Córdoba) and Brazil (Distrito Federal, Minas Gerais, Rio Grande do Sul and São Paulo) (Figure 22). There are records from Paraguay in Ratcliffe et al. (2023).
Remarks
Arrow (1937a) described B. cylindricus based on two specimens (one of each sex) and provided the diagnosis by comparing it with B. laticfex and B. cribrarius. Endrödi (1969) did not examine the type specimens of B. cylindricus and provided a short diagnosis comparing it with B. ascanius. Despite his information on the high similarity among B. ascanius and B. cylindricus, however, these two species can be distinguished by the new diagnostic characters provided here.
description: Published as part of Duarte, Paulo R. M., Dupuis, Fabien & Grossi, Paschoal C., 2025, Taxonomic revision of the Bothynus ascanius (Kirby, 1819) (Coleoptera: Melolonthidae: Dynastinae) species group, pp. 663-737 in Journal of Natural History 59 (9 - 12) on pages 692-697, DOI: 10.1080/00222933.2025.2456579, http://zenodo.org/record/14971553