Bothynus nyx Ratcliffe, 2010

Duarte, Paulo R. M., Dupuis, Fabien & Grossi, Paschoal C., 2025, Taxonomic revision of the Bothynus ascanius (Kirby, 1819) (Coleoptera: Melolonthidae: Dynastinae) species group, Journal of Natural History 59 (9 - 12), pp. 663-737 : 716-717

Bothynus nyx Ratcliffe, 2010

( Figures 2i, 3k, 8c, 9i, j, 10b, 13k, 14k, 16a, 17g, h, 23)

Bothynus nyx

Ratcliffe 2010: 105 (original description); López-García et al. 2016: 497 (checklist).

Diagnosis

Bothynus nyx is a large species (32.5–34.5 in length) that is distinguished from other species of the ascanius group by the following combination of characters: Both sexes bearing pronotum with a transverse, deep and oval cavity ( Figure 8 (c)), besides the elytra with small punctures ( Figures 10 (b)); inner protarsal claw of males only with a ventromedial process; apical half of parameres with parallel sides in caudal view ( Figure 13 (k)), combined to sharply apex in lateral view ( Figure 14 (k)). Bothynus nyx is comparable to B. laevipennis in the males with large and deep pronotal cavity, besides the inner protarsal claw only with a ventromedial process along tarsomere 5 without a ventral process.

Type material

Holotype male, labelled: (a) ‘ BOLIVIA: Dep. Santa Cruz / Bermejo, Refugio Los Volcanes / Hotel area , 18°06'18''S 63°35'54''W / 09.xii.2003, at night/coll D.J. Mann and A.C. Hamel’; (b) ‘OUMNH-2004-005/ D.J.Mann and C.Hamel coll./ Pres. Mann and Hamel, 2004’; (c) ‘ BOTHYNUS /NYX/RATCLIFFE/HOLOTYPE’ [red label, partly handwritten] ( OUMNH) ( Figure 2 (i)).

Additional material

BOLIVIA: Caranavi: iv .2008 – 1 male, 1 female ( FDPC) . La Paz: Coroico, 22 .i .2009 – 1 male, 1 female ( EPGC).

Male redescription ( Figure 3 (k))

Length: 32.5–34.5 mm. Width: 17.8–18.0 mm. Colour: Head, pronotum, tibiae and tarsi dark reddish-brown; elytra and ventral surface reddish brown. Head: Clypeus subtrapezoidal (posterior width about 3.0–3.1 times wider than anterior one); lateral margins sinuous, slightly constricted at anterior half, subparallel at posterior half; anterior teeth usually lobed, transverse; surface transversely rugose, glabrous. Frontoclypeal carina well marked, slightly sinuous, nearly reaching the lateral margins. Frontal surface transversely covered with strong rugosity; setae scarce, arranged on sides close to eyes; middle area glabrous. Interocular width equals 3.4–3.8 transverse eye diameters. Ocular canthus transverse, arched. Mouthparts: Mandible with apical tooth diagonally truncate apically; medial tooth with broadly lobed apex, larger than apical one; basal tooth rounded, smaller than previous ones. Labium suboval, flattened, surrounded with dense, large, deep, setigerous punctures; disc weakly rugose, with scarce setae. Antennae: Club flattened, broad, about 1.6 times larger than antennomeres 2–7 combined. Prothorax: Pronotal anterior tubercle strong, conical, raised on a transverse edge; cavity deep, wide (occupying over 1/2 of anterior area), transverse, oval ( Figure 8 (c)), sometimes limited posteriorly by a small tubercle. Pronotal cavity transversely rugose, limited laterally with small, scarce punctures; anterior pronotal corners with large, deep, from contiguous to coalescent; pronotal sides covered with minute or small punctures ( Figure 9 (i,j)), except for an area close to lateral margins with dense, small punctures; punctures minute on posterior area behind cavity, becoming large, dense, coalescent, rugose towards posterior margin. Pterothorax: Scutellar plate finely punctate. Elytral striae barely marked, covered with ocellate, small punctures ( Figure 10 (b)); punctures on sutural stria from contiguous to separated by 1 puncture diameter apart; other striae with punctures from 1–4 puncture diameters apart. Legs: Inner protarsal claw with a small, ventromedial, triangular to lobed process. Mesofemur nearly completely setose ventrally. Metafemur with minute punctures on ventral surface. Meso- and metatibia with medial carina strongly produced. Abdomen: Tergite 7 with stridulatory apparatus formed by 1 band of finely marked striae. Tergite 8 entirely covered with strong rugosity, setae scarce. Sternites 4–7 strongly rugopunctate on sides, with small punctures transversely scattered at middle of disc; sternites 5–7 with a row of setigerous punctures arranged on sides, disc glabrous; sternite 8 rugopunctate on sides, glabrous. Aedeagus: Parameres, in dorsal view, with basal half rounded laterally, outer margins becoming subparallel towards apical half; apical lobes broad ( Figure 13 (k)). Parameres, in lateral view, with acute apex, bearing a transversal carina between dorsal and ventral surfaces; basal area bearing a weak carina ( Figure 14 (k)).

Female description ( Figure 16 (a))

Length: 33.0 mm. Width: 18.4 mm. Similar to male, except for: Prothorax: Pronotal cavity posteriorly limited by a transverse tubercle. Scutellar plate with scarce, setigerous punctures. Legs: Inner protarsal claw simple, without ventromedial lobe. Abdomen: Sternite 8 densely rugopunctate, with short setae confined on sides.

Distribution

Known only from Bolivia (La Paz and Santa Cruz) ( Figure 23). Bothynus nyx is related to sub-Andean areas from Bolivia, with disjunctive distribution from B. laevipennis .