Didrepanephorus heterocolor Qiu, Zhao & Xu, 2021

Qiu, Jian-Yue, Zhao, Ming-Zhi & Xu, Hao, 2021, Description of a new species of the genus Didrepanephorus Wood-Mason, 1878 (Coleoptera: Scarabaeidae: Rutelinae) from China with notes on allied species, Zootaxa 4933 (4), pp. 493-513 : 498-501

Didrepanephorus heterocolor Qiu, Zhao & Xu , new species -•镰'•龟

( Figs. 11–20 , 35–36 , 57–64 , 70 )

Type material. Holotype: (♂, MYNU), CHINA: Maolan Nature Reserve , Loudousenlin , Libo County, Guizhou , 25°17′51″ N, 108°04′28″ E, alt. 679 m, Ri-Xin JIANG leg. // pupa in 2017.IV.29, adult emerged in 2017.V ; Paratypes (15♂♂, 22♀♀): CHINA : 1♀ (Allotype, MYNU) , 1♀ ( MYNU), same label data as holotype; 2♂♂ , 2♀♀ ( MYNU), 2017.V.1, Maolan Nature Reserve, Loudousenlin , Libo County, Guizhou, 25°17′51″ N, 108°04′28″ E, alt. 679 m, Ri-Xin JIANG leg.; 4♂♂ , 5♀♀ ( SHNU), F 1 generation of one female from Maolan Nature Reserve, 2017, Ri-Xin JIANG leg. // adult emerged in 2018.II; 2♂♂ , 2♀♀ ( MYNU), Maolan Nature Reserve, La’nei , Weng’ang , Libo County, Guizhou, alt. 800 m, Jian-Yue QIU & Hao XU leg. // mature larva in 2012.VIII.11, adult emerged in 2013.IV ; 3♀♀ ( MYNU), F 1 generation of one female from Maolan Nature Reserve, 2012, Jian-Yue QIU & Hao XU leg. // adult emerged in 2014.V; 1♂ , 4♀♀ ( MYNU), Maolan Nature Reserve, La’nei , Weng’ang , Libo County, Guizhou, Jian-Yue QIU & Hao XU leg. // mature larva in 2013.VII.25, adult emerged in 2014.IV ; 1♀ ( MYNU), 2018. VI.12, Maolan Nature Reserve, Dongduo , Libo County, Guizhou, alt. 790 m, Jian-Yue QIU & Hao XU leg.; 4♂♂ , 3♀♀ ( GFGY), 1988.V.24, Maolan Nature Reserve, Banzhai , Libo County, Guizhou, alt. 540 m; 1♂ ( GFGY), 1990. V.14, Maolan Nature Reserve , Banzhai to Limingguan , Libo County , Guizhou, alt. 570 m; 1♂ ( GFGY), without label but should be also from the same nature reserve .

Additional material examined. 3♀♀ ( MYNU), same label data as holotype. These females were deformed during eclosion and thus removed from the type series .

Description of the holotype (male). General: Body oval and convex, hairs and setae yellowish-brown ( Figs. 11–12 ). Head: Clypeus reddish-brown, other portions dark brown. Clypeus flat, trapezoidal, anterior margin feebly arcuate; anterior angles rounded, sides strongly convergent anteriad and expanded in basal half, concave near middle, then almost subparallel in apical half; with dense large punctures, coarse but not punctured near anterior margin; anterior margin with some short setae. Frontal-clypeal suture almost absent, represented by a short carina at each side. Frons and vertex with dense large punctures and dense, erect long setae. Eye-canthus wide and truncate at outer margin, not extends beyond outermost point of eye, anterior angle nearly right angle. Antennal scapus reddish-brown, base of antennal club dark brown, gradually changed fulvous to apex, length of antennal club distinctly longer than antennomeres 2–7 combined. Labrum exposed, anterior margin deflected and concave at middle, dorsal surface sparsely microsculptured, with sparse, short and long setae. Mandible dark brown, broadest at base, lower margin deeply constricted before basal tooth, apex sharply bended upward. Maxillary palpi and labial palpi dark brown, simple. Mentum with dense punctures and long erect setae, anterior margin slightly concave in middle. Gula dark brown, glabrous and matt. Pronotum: Dark brown, each side with an indistinct orange-brown patch near middle. Strongly convex, 1.45 times as wide as long, widest near middle. Anterior margin distinctly bisinuate; anterior marginal membrane distinct, obsolete before reaching anterior angle. Sides feebly concave and slightly convergent posteriad in basal half, roundly and broadly curved at middle, strongly convergent anteriad in apical half. Posterior margin broadly protruding in middle. Basal marginal line interrupted before scutellum, all other marginal lines completed. Anterior angle moderately protruding, posterior angle slightly protruding, both blunt at apex. Surface with dense small punctures, rugopunctate along lateral margin, disc with a longitudinal medial line. Most areas of disc with rather dense semierect long setae, setae on lateral portions being shorter. Scutellum: Black. Nearly short triangular, lateral margin slightly curved, apex rounded. Surface with dense large punctures and short setae except for midline and margin. Elytra: Convex. Margin, suture and apical umbone black. Almost as wide as long, widest at middle. Primary stria 1 clearly defined by a row of strial punctures, other intervals unrecognizable. Humeral umbone and apical umbone convex. Surface coarse, with sparse, shallow, round large punctures and dense, short, semierect setae, alternated by rather sparse, short erect setae. Epipleura glabrous. Ventral thoracic surface: Dark brown, posterior part of ventral mesothoracic surface reddish-brown ( Fig. 12 ). Base of ventral prothoracic and anterior half of ventral metathoracic surfaces with dense long hairs; anterior half of ventral prothoracic and posterior half of ventral mesothoracic surfaces with erect short setae. Prosternal process small, horizontally broad, shield-liked with an medial carina. Punctures on ventral mesothoracic surface round and gradually changed into sinuous striolae laterad. Metasternum moderately bulging along glabrous midline. Propygidium: Dark brown. Surface coarse, with dense, semierect short setae. Pygidium: Convex. Dark brown. Disc coarse, lateral and posterior portions indistinctly and transversely puncatate. Setosus as in propygidium. Abdomen: Dark brown, distinctly curved in lateral view, abdominal ventrites 1–4 abbreviated ( Fig. 12 ). With dense round punctures and semierect long setae. Posterior margin of abdominal ventrite 6 broadly and distinctly concave medially, with a row of dense, semierect long setae. Legs: Dark brown, with moderately dense, erect long setae. Femora with dense punctures; tibiae with dense, coarse and irregular punctures. Inner protarsal claw simple and thickened, outer protarsal claw smaller and sharp at apex. Outer meso- and metatarsal claws widely and deeply spilt into two branches respectively, the upper branches thinner and sharper; in outer mesotarsal claw the two branches equal in length, in outer metatarsal claw the upper branch slightly longer than the lower branch. Inner meso- and metatarsal claws more curved than the outer ones. Protibia with three distinct and acute teeth. Protibial spur situates at the level of middle protibial tooth, vertically orient forwards. Meso- and metatibiae bidentate at apical edges, the upper tooth in mesotibia distinctly protruding. Protarsus strongly thickened; protarsomeres 2–4 abbreviated; protarsomere 4 ventrally with a short blunt protrusion; meso- and metatarsomeres 4 each with an acute ventroapical protrusion, each protrusion with a pair of spines at base; tarsomeres 5 of all legs with a small and blunt ventral protrusion in basal third. Aedeagus: As Figs. 35–36 .

Paratypes. Male: Larger males have longer mandibles ( Figs. 15–18 ). Female: Body color darker; head, pronotum, scutellum, pygidium, ventral surface, and legs black; the anterior 1/2 to 3/4 of elytron fulvous, and the posterior 1/2 to 1/4 dark brown or black ( Figs. 13 , 19–20 ). Mandible small, short, nearly triangular; outer edge bidentate, apical tooth acute and bends upwards, second tooth broadly rounded. Clypeus longer than in male; anterior margin straight or feebly emarginated, distinctly convex. Labrum not visible in dorsal view. Antennal club slightly shorter. Intervals defined by rows of close and large punctures; three inner primary striae feebly convex, with scattered small punctures; interstices with dense, irregular large punctures. Punctures on dorsal surface of head, pronutum, scutellum and elytra less but larger, deeper and coarser. Setae and hairs on the whole body surface rather sparser. Abdominal ventrites convex; abdominal ventrite 1 abbreviated medially, abdominal ventrites 2–4 almost equal in length ( Fig. 14 ); posterior margin of abdominal ventrite 6 straight medially. Protarsus smaller, but metatibia stronger. Tarsomeres 4 of all legs each with an acute ventroapical protrusion, each protrusion ofmeso- and metatarsomeres 4 with a pair of spines at base.

Measurements. Body length: male 15.0–17.8 mm (holotype 23.5 mm), female 14.2–18.1 mm (allotype 18.1 mm); body width: male 7.8–9.1 mm (holotype 9.7 mm), female 8.1–10.0 mm (allotype 10.0 mm).

Differential diagnosis. Didrepanephorus heterocolor new species is similar to D. nishiyamai and D. subvittatus, but the body color of the latter two species is reddish-brown. This new species can be separated from the latter two also by the following characters: antennal club bicolor (base dark brown and gradually changed fulvous to apex, Figs. 15–18 ), while unicolor in D. nishiyamai ( Figs. 29–30 ) and D. subvittatus ( Figs. 31–32 ); length of male antennal club as long as antennomeres 2–7 combined ( Figs. 11–12 ), while longer in D. nishiyamai ( Figs. 21–22 ) and shorter in D. subvittatus ( Figs. 25–26 ); male mandibles deeply constricted before base tooth ( Fig. 15 ), while slightly constricted in D. subvittatus ( Figs. 31 ); anterior margin of male mentum slightly depressed in middle, while distinctly depressed in D. subvittatus ; setae on male pronotum longer ( Figs. 15–18 ) than that of D. nishiyamai ( Fig. 29 ) and D. subvittatus ( Fig. 31 ); female with dense and coarse punctures on head and pronotum ( Figs. 13–14 , 19–20 ), while those punctures sparser and finer in D. nishiyamai ( Figs. 23 , 30 ) and D. subvittatus ( Figs. 27 , 32 ).

Etymology. The specific epithet “ heterocolor ” is a combination of the Greek “ heteros ” and Latin noun “ color ” meaning different colors, in allusion to the significant sexual dichroism of this new species.

Distribution. China: Guizhou.

Natural history. This species is only known from the Maolan Nature Reserve in southern Guizhou, China, where has a subtropical forest of karst landform at elevation of 550–850 m ( Figs. 57–58 ). The mature larvae and newly emerged adults have been found in humid rotten wood in later April and early May ( Figs. 59–60, 63 ), and an exhausted female was collected by a light trap in early June 2018. It is suggested the peak of activity for adults should be mid and later May. In the field, third instar larvae of the new generation can be excavated in rotten wood of broad-leaved trees as early as late July ( Fig. 60 ). Wild-collected larvae were raised in small plastic containers filled with pieces of wet, rotten oak wood at the temperature below 26°C. Females have been bred for reproduction under artificial conditions ( Figs. 61–62, 64 ), and several larvae were successfully developed to the adult stage (personal observation, Jian-Yue Qiu, 2012–2013; Jun Qi, 2017–2018).

Remarks. The body color of this new species is sexually dichroic, the male is dark brown, while the female has a black body with bicolor elytra. This phenomenon is distinctive in this genus, and D. arnaudi was the only case before. In general appearance, D. heterocolor new species is close to D. nishiyamai and D. subvittatus , and they can be attributed to a species group ( D. subvittatus group) characterized by the combination of the following characters: lower margin of male mandible with a distinct concavity before basal tooth; pronotum evenly covered with untufted dense setae in male, with sparse short setae in female; abdominal ventrites with sparse setae; phallobase evenly curved in profile; parameres fused basally.

Figures

FIGURE 70. Known distribution of four Didrepanephorus Wood-Mason, 1878 species. Type locality of D. mucronatus Arrow, 1921 is missing because the precise location is unknown.

FIGURES 11–14. Habitus of Didrepanephorus heterocolor Qiu, Zhao & Xu, new species (dorsal and ventral view). 11–12, male holotype; 13–14, female allotype.

FIGURES 15–20. Habitus of Didrepanephorus heterocolor Qiu, Zhao & Xu, new species (oblique view). 15–18, males in different body sizes (16 holotype); 19–20, females in different elytral colorations (19 allotype).

FIGURES 33–40. Male genitalia of Didrepanephorus Wood-Mason, 1878 species (showing parameres in dorsal and ventral views). 33–34, D. mucronatus Arrow, 1921; 35–36, D. heterocolor new species (holotype); 37–38, D. nishiyamai Muramoto, 2006; 39–40, D. subvittatus Benderitter, 1922.

FIGURES 57–64. Habitat and different stages of Didrepanephorus heterocolor Qiu, Zhao & Xu, new species. 57, forest in Maolan Nature Reserve (Guizhou, China); 58–59, a closer view of habitat and pupal cells in rotten wood (both photograph by Ri-Xin Jiang); 60, a larva under the bark of decayed wood in wild; 61–62, pupa and newly emerged female in pupal cells in artificial conditions; 63, male in a pupal cell in rotten wood (photograph by Ri-Xin Jiang); 64, egg in artificial conditions.

FIGURES 29–32. Habitus of Didrepanephorus Wood-Mason, 1878 species (oblique view). 29–30, D. nishiyamai Muramoto, 2006: 29, male; 30, female. 31–32, D. subvittatus Benderitter, 1922: 31, male; 32, female.

FIGURES 21–24. Habitus of Didrepanephorus nishiyamai Muramoto, 2006 (dorsal and ventral view). 21–22, male (Mt. Dayaoshan); 23–24, female (Mt. Damingshan).

FIGURES 25–28. Habitus of Didrepanephorus subvittatus Benderitter, 1922 (dorsal and ventral view). 25–26, male; 27–28, female. (both from Tam Dao).