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 .

Figures

Figure 2. Types,with their respective labels on the right: (a) Bothynus ascanius (Kirby,1819); (b) Bothynus cribrarius (Fairmaire, 1878); (c) Bothynus cyclops (Burmeister, 1847); (d) Bothynus cylindricus Arrow, 1937; (e) Bothynus deiphobus (Burmeister, 1847); (f) Bothynus laevipennis Arrow, 1937; (g) Bothynus laticifex Burmeister, 1847; (h) Bothynus minor Steinheil, 1872; (i) Bothynus nyx Ratcliffe, 2010; (j) Bothynus fabius (Fairmaire, 1878); (k) Bothynus thrix Hardy, 2017.

Figure 3. Male dorsal habitus: (a) Bothynus arriagadae sp. n.; (b) Bothynus ascanius; (c) Bothynus cribrarius; (d) Bothynus cyclops; (e) Bothynus cylindricus; (f) Bothynus deiphobus; (g) Bothynus gisae sp. n.; (h) Bothynus laevipennis; (i) Bothynus laticifex; (j) Bothynus minor; (k) Bothynus nyx; (l) Bothynus ovalatus sp. n.

Figure 8. Dorsal view of male pronotum: (a) Bothynus ascanius; (b) Bothynus cylindricus; (c) Bothynus nyx; (d) Bothynus robustus sp. n. pc = pronotal cavity.

Figure 9. Laterodorsal view of male pronotum (a, c, e, g, i, k), detail of the posterior sides (b, d, f, h, j, l): (a, b) Bothynus ascanius; (c, d) Bothynus cylindricus (black arrow points to posterior marginal rugosity); (e, f) Bothynus laevipennis; (g, h) Bothynus laticifex; (i, j) Bothynus nyx; (k, l) Bothynus rufipennis sp. n.

Figure 10. Dorsal view of the left elytron (a–c), anterior corner of the right elytron (d–e): (a) Bothynus laevipennis; (b) Bothynus nyx Ratcliffe, 2010; (c) Bothynus thrix; (d) Bothynus arriagadae sp. n. (black arrow points to the absence of marginal epipleura); (e) Bothynus ovalatus sp. n.

Figure 13. Parameres in caudal (a–r) and frontal views (s, t): (a) Bothynus arriagadae sp. n.; (b) Bothynus ascanius; (c) Bothynus cribrarius; (d) Bothynus cyclops; (e, s) Bothynus cylindricus (arrows point to basal constriction); (f) Bothynus deiphobus; (g) Bothynus gisae sp. n.; (h) Bothynus laevipennis; (i, t) Bothynus laticifex; (j) Bothynus minor; (k) Bothynus nyx; (l) Bothynus ovalatus sp. n. (arrows point to contiguous basis of the apical lobes); (m) Bothynus robustus sp. n.; (n) Bothynus rufipennis sp. n.; (o) Bothynus sapukai sp. n. (arrows point to the basal separation of the apical lobe); (p) Bothynus scutellopunctatus sp. n.; (q) Bothynus fabius; (r) Bothynus thrix. al = apical lobe.

Figure 14. Parameres in lateral view: (a) Bothynus arriagadae sp. n.; (b) Bothynus ascanius; (c) Bothynus cribrarius; (d) Bothynus cyclops; (e) Bothynus cylindricus; (f) Bothynus deiphobus; (g) Bothynus gisae sp. n.; (h)Bothynus laevipennis;(i)Bothynus laticifex;(j) Bothynusminor; (k)Bothynus nyx;(l)Bothynus ovalatus sp.n.; (m) Bothynus robustus sp. n.; (n) Bothynus rufipennis sp. n.; (o) Bothynus sapukai sp. n.; (p) Bothynus scutellopunctatus sp. n.; (q) Bothynus fabius; (r) Bothynus thrix.

Figure 16. Female dorsal habitus (continuation):(a) Bothynus nyx; (b) Bothynus ovalatus sp. n.; (c) Bothynus rufipennis sp. n.; (d) Bothynus sapukai sp. n.; (e) Bothynus scutellopunctatus sp. n.; (f) Bothynus fabius; (g) Bothynus thrix (paratype).

Figure 17. Laterodorsal view of female pronotum (a, c, e, g, i, k), detail of the posterior sides (b, d, e, g, I, k): (a, b) Bothynus ascanius; (c, d) Bothynus laticifex; (e, f) Bothynus moroni sp. n.; (g, h) Bothynus nyx (arrow points to the posterior tubercle on pronotal cavity); (i, j) Bothynus rufipennis sp. n.; (k, l) Bothynus scutellopunctatus sp. n.

Figure 23. Known geographical distribution of Bothynus ascanius, Bothynus laevipennis, Bothynus Moroni sp. n., Bothynus nyx, Bothynus robustus sp. n., and Bothynus scutellopunctatus sp. n.