Callistethus hamus Lu & Zorn

Lu, Yuan-Yuan, Zorn, Carsten, Kral, David & Bai, Ming, 2019, Description of Callistethus hamus sp. nov. (Coleoptera, Scarabaeidae, Rutelinae) from continental Southeast Asia using synchrotron to illustrate the aedeagus, ZooKeys 881, pp. 1-11 : 3-6

Callistethus hamus Lu & Zorn sp. nov. Figs 1-9 , 19-23

Type locality.

China, Southern Yunnan, 23 km NW of Jinghong, vicinity of Nan Ban, Xishuangbanna [Prefecture], 22°09.49"N, 100°39.92"E, 730 m.

Material examined.

Holotype (HT). CHINA • ♂; Yunnan Province, Dai Autonomous Prefecture of Xishuangbanna, Jinghong City, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 20 May 2008; A Weigel leg.; NMEC.

Paratypes.

CHINA • 1 ♀; same data as the holotype • 1 ♂; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 5 Jun. 2008; A. Weigel leg.; NMEC; [Micro-CT specimen] • 1 ♂ 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 5 Jun. 2008; A. Weigel leg.; CZPC • 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 15 Jun. 2008; NMEC • 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 5 Jun. 2008; A. Weigel leg.; NMEC • 1 ♂; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 12 May 2008; A. Weigel leg.; NMEC • 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 16 May 2009; Malaise trap; L.Z. Meng leg.; IZAS IOZ(E)1966878 • 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°07.85'N, 100°40.12'E; 26 May 2009; Malaise trap; L.Z. Meng leg.; IZAS IOZ(E)1966879 • 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 22°09.49'N, 100°39.92'E; 16 May 2009; flight interception traps; L.Z. Meng leg.; IZAS IOZ(E)1966880 • 1 ♀; Yunnan Province, Xishuangbanna, Jinghong, Na Ban River Watershed National Nature Reserve ; 31. Jul. 2013; FWPC • 1 ♂; Yunnan Province, Menghai, Menghun Town ; 21°50.48'N, 100°23.15'E; 4 Jun. 1958; L.Y. Zheng leg.; IZAS IOZ(E)1966104 • 1 ♀; Yunnan Province, Xishuangbanna, Menghai, Menghun Town ; 21°50.48'N, 100°23.15'E; 1 Jun. 1958; X.W. Meng leg.; IZAS IOZ(E)1966106 • 1 ♀; Yunnan Province, Xishuangbanna, Menghai, Menghun Town ; 21°50.48'N, 100°23.15'E; 4 Jun. 1958; L.Y. Zheng leg.; IZAS IOZ(E)1966107 • 1 ♀; Yunnan Province, Xishuangbanna, Menghai, Mengzhe Town ; 21°59.15'N, 100°16.02'E; 8 Jul. 1958; S.Y. Wang leg.; IZAS IOZ(E)1966105 .

LAOS • 1 ♂; Vientiane Province, Phou Khao Khoay ; 18°24.15'N, 103°02.15'E; 4-17 May 2005; P. Moravec leg.; CZPC .

VIETNAM • 4 ♂♂ 2 ♀♀; Lâm Đ ồng Prov., Dambri, B ảo Lâm; 11°38.42'N, 107°44.52'E; May 2017; local collector leg.; CZPC • 1 ♀; Lâm Đ ồng Prov., B ảo Lộc; 11°32.88'N, 107°48.46'E; March 2018; local collector leg.; CZPC • 5 ♂♂ 1 ♀♀; Lâm Đ ồng Prov., B ảo Lộc; 11°32.88'N, 107°48.46'E; March 2018; local collector leg.; CZPC • 1♂ 1 ♀; Lâm Đ ồng Prov., B ảo Lộc; 11°32.88'N, 107°48.46'E; March 2017; local collector leg.; MSPC .

Description of holotype (♂). Body shape elongate ovoid, convex.

Colour. Head including antenna orange-brown, with two small black spots on vertex; pronotum orange-brown with two moderately large black spots in the middle of each side; an additional longitudinal stripe near the lateral margin (not reaching anterior and posterior margins) separating the yellow sides from the orange disc ( Figs 1 , 4 ); elytra light reddish-brown with black markings as follows: an elongate spot on humeral callus, another smaller spot beneath shoulder at lateral margin, a zig-zag band of loosely connected spots crossing the middle of elytra, another zig-zag band shortly before the posterior margin ( Fig. 1 ); propygidium black with a transverse yellow spot at the outer posterior margin ( Fig. 5 ); pygidium black with a narrow yellow longitudinal middle line ( Fig. 5 ); underside yellow with black markings, with slight metallic shine ( Fig. 2 ); black macula in the middle and at extremities of femurs; various black markings present on all tibiae; pro- and mesotarsi brown, metatarsus black; major part of meso- and metaventrite black; meso-metaventral process yellow; major part of abdominal ventrites 1-3 yellow, abdominal ventrites 4-6 black with lateral yellow spot ( Fig. 2 ).

Head. Clypeus subtrapezoidal, anterior angles rounded; anterior margin weakly reflexed, very densely, transversely rugo-punctate; frons rugo-punctate, with very shallow impression in the middle, confluently punctate at sides; vertex finely and sparsely punctate in the middle, more coarsely punctate laterally; ratio interocular width/width of head approximately 0.71; antennal club longer than antennomeres 1-6 combined ( Figs 1 , 4 ).

Pronotum approximately 1.89 times wider than long; sparsely and finely punctate, punctures very fine on disc, becoming gradually larger toward the sides; surface with additional micropunctures; anterior angles sub-rectangular; posterior angles obtuse; broadest at base; sides evenly curved in the middle, straight and strongly converging before anterior angles; sides very slightly sinuate near posterior angles; basal marginal line only present near posterior angles; anterior marginal line indistinct in the middle ( Fig. 4 ).

Scutellum subtriangular, slightly broader than long, finely and sparsely punctate ( Fig. 4 ).

Elytra regularly striate; primary striae and secondary stria of subsutural interstice sulcate in posterior half, therefore intervals flat in anterior half and gradually more convex posteriad; strial punctation distinct, coarse; 2nd and 3rd interstices each with an indistinct row of punctures; elytral surface with additional sparse micropunctation; humeral umbone and apical protuberance rather prominent; epipleuron broad near humerus, ending approximately at the middle of elytron; posterior margins evenly, separately rounded; apico-sutural angle forming small dent ( Fig. 1 ).

Pygidium convex; apex broadly rounded; moderately densely, coarsely punctate; apex with several long, erect brownish setae ( Fig. 5 ).

Ventral thoracic surface smooth ( Fig. 2 ).

Meso-metaventral process very long, reaching middle of procoxae; projecting upward in lateral view; apex acute ( Fig. 3 ).

Abdominal ventrites with transverse row of rather sparse brown setae (usually only in lateral part); ventrites 1 and 2 carinate laterally ( Figs 2 , 3 ).

Legs. Mesofemur with two bands of long brown setae: one along anterior margin; another transverse row of punctures parallel to posterior margin. Protibia bidentate, rather slender; proximal tooth short, situated close to the rather short, weakly outwards curved apical tooth; inner spur short, articulated in opposite to proximal tooth. Metatibia strongly fusiform; protarsomere 5 shorter than tarsomeres 1-4 combined in all legs; inner protarsal claw slightly widened and deeply incised apically, lower margin with obtuse angle basally, upper branch spiniform; outer mesotarsal claw long, curved, deeply incised at apex, upper branch spiniform; metatarsal claws somewhat unequal, outer claw distinctly broader and longer than inner ( Figs 1-3 ).

Aedeagus. Parameres short, with the hook-like apex in lateral view. See Figs 6-8 .

Female. Abdominal ventrites 4-6 with extensive yellow markings. Apical tooth of protibia long and somewhat spatulate; protarsus articulated slightly basally of level of proximal tooth; inner spur long; protarsomere 1 as long as combined length of protarsomeres 2-4; antennal club short, only slightly longer than antennomeres 2-6 combined.

Measurements.

Total body length 11.5-14.4 mm (HT 11.8 mm), total body width 6.5-8.4 mm (HT 7.5 mm).

Morphological variability.

Vertex with or without two black spots. Elytral spots vary slightly in shape and size. The extend of black markings of the ventral side variable. The secondary longitudinal rows of punctures in interstices 2 and 3 sometimes distinct until the posterior half. Shape of parameres very consistent ( Figs 19-23 , Appendix 1).

Differential diagnosis.

Callistethus hamus sp. nov. resembles several other, similarly coloured South East Asian species of this genus. The reddish colour combined with black markings is also found in C. maculatus ( Guérin-Méneville, 1834), C. picturatus ( Candèze, 1869), C. rachelae (Arrow, 1917), C. spiniferus (Ohaus, 1915), and C. stolidopygus (Ohaus, 1915). The new species is most similar to C. rachelae , which also has only two black spots on the pronotum, not four as all other red species ( Figs 10-18 ). Callistethus hamus sp. nov. differs from C. rachelae primarily in the shape of the aedeagus ( Figs 6-8 , 15-17 ). The ventral margin of the parameres of C. rachelae is somewhat membranous and soft, but fully sclerotised in C. hamus sp. nov. The apices of the parameres in C. hamus sp. nov. are longer and more strongly curved compared to those of C. rachelae ( Figs 15-17 ).

Etymology.

The specific epithet refers to the hook-like shape of the parameres of the new species.

Collecting data.

Specimens collected in the Naban River Watershed National Nature Reserve by Lingzeng Meng and Andreas Weigel were collected with cross-window traps in the tree canopy and malaise trap.

Distribution.

China (Yunnan), Laos (Vientiane), Vietnam ( Lâm Đ ồng) ( Fig. 24 ).

Figures

Figure 24. Map of Southeast Asia showing distributions of Callistethus hamus and Callistethus rachelae.

Figures 1 - 9. Holotype of Callistethus hamus Lu & Zorn, sp. nov. 1 - 3 habitus 1 dorsal view 2 ventral view 3 lateral view from left 4 head and pronotum 5 propygidium and pygidium 6 - 8 aedeagus 6 dorsal view 7 lateral view from right 8 ventral view 9 label. Key: Sc. 1, Scale bars: 5 mm (1 - 3); Sc. 2, 5 mm (4, 5); Sc. 3, 1 mm (6 - 8).

Figures 19 - 23. 3 D model for aedeagus of Callistethus hamus Lu & Zorn, sp. nov. Paratype from China, Yunnan. These photos are screen shots of the 3 D model of the aedeagus.

Figures 10 - 18. Holotype of Callistethus rachelae (Arrow, 1917). 10 - 12 habitus 10 dorsal view 11 ventral view 12 lateral view from left 13 head and pronotum 14 propygidium and pygidium 15 - 17 aedeagus 15 dorsal view 16 lateral view from right 17 ventral view 18 label. Key: Sc. 1. Scale bars: 5 mm (10 - 12); Sc. 2, 5 mm (13, 14); Sc. 3, 1 mm (15 - 17).