Dicronocephalus chenliae, Ythier & François, 2023

Qiu, Jian-Yue, 2023, Flower beetles of the Asian genus Dicronocephalus Hope (Coleoptera: Scarabaeidae: Cetoniinae): description of a new species from China and intraspecific variations of D. adamsi, Faunitaxys 11 (64), pp. 1-11 : 2-4

Dicronocephalus chenliae sp. nov.

( Fig. 1 -12, 17- 19 & 38 -44)

ZooBank:https://zoobank.org/ 09FB0C3A-B3CB-4A60-98F3-6CC35FF03DA9

Holotype ♂ ( MYNU, Fig,1 - 3 & 10- 12), Jiahe Village, Zhonglu Township , Weixi Cunty, Diqing Prefecture, Yunnan Province, China, 15.VI.2017, Zi-Chun Xiong leg .

Paratypes

- 2 ♂, 1 ♀ ( OXUM), China, Yunnan-Sichuan, MekongValley , between 26° & 29°N, ≈ 1930, coll. G. Forrester, OUMNH-2004-038// Dicronocephalus sp. , 28.IV.2017, QIU Jian-Yue ;

- 1 ♂, 1 ♀ ( MYNU), Manjiu Village, Manwan Township , Yunxian Cunty, Lincang City, Yunnan Province, China, VI.2013, Zi-Chun Xiong leg .;

- 4 ♂, 1 ♀ ( MYNU), ManjiuVillage, Manwan Township , Yunxian Cunty, Lincang City, Yunnan Province, China, V.2014, Zi-Chun Xiong leg .;

- 4 ♂, 2 ♀ ( MYNU), Jiahe Village, Zhonglu Township , Weixi Cunty, Diqing Prefecture, Yunnan Province, China, 15.VI.2017, Zi-Chun Xiong leg .;

- 1 ♂, 1 ♀ ( BMNH), 1 ♂, 1 ♀ ( EUMJ), 1 ♂, 1 ♀ ( HKCJ), 2 ♂ ( IZAS), 2 ♂, 1 ♀ ( KSCJ), 1 ♂, 1 ♀ ( MFNB), 1 ♂, 1 ♀ ( MNHN), 74 ♂, 6 ♀ ( MYNU), 1 ♂, 1 ♀ ( SEHU), 2 ♂ ( SYSM), Weideng Township , Weixi Cunty, Diqing Prefecture, Yunnan Province, China, 20.VI-5.VII.2023, Zhong-Cheng Yu leg .;

- 48 ♂, 22 ♀ ( MYNU), Zhonglu Township , Weixi Cunty, Diqing Prefecture, YunnanProvince, China, 10.VI-18.VI.2023, Zhong-ChengYuleg .;

- 11 ♂, 1 ♀ ( MYNU), Zhonglu Township , Weixi Cunty, Diqing Prefecture, YunnanProvince, China, 5.VI.2022, Yan-YanWangleg .;

- 25 ♂, 15 ♀ ( MYNU), Tuanshan Village, Daxueshan Township , Yongde Cunty, Lincang City, Yunnan Province, China, 15 -18.V.2022, Hua-Chang Li leg .;

- 21 ♂, 5 ♀ ( MYNU), Tuanshan Village, Daxueshan Township , Yongde Cunty, Lincang City, Yunnan Province, China, 12.VI.2023, Hua-Chang Li leg .

Diagnosis. – The new species is similar to D. adamsi , but the male can be distinguished by:

1 - Tomentum yellowish-gray, while grayish in D. adamsi ;

2 - Clypeus further downward extended and clypeal gap distinctly deeper and wider (Fig. 12, indicated by the red arrow);

3 - Lateral tooth of horn evidently smaller;

4 - For large and middle sized individuals, tip of horn bends inward in dorsal view ( Fig. 1 ), while forward or outward in D. adamsi ( Fig. 23, 25 - 26 & 28 -30 );

5 - Scutellum fully clad with tomentum, while scutellum partly clad with tomentum or without tomentum in most of D. adamsi ;

6 - Pronotal bands “/\” shaped, while more parallel in D. adamsi .

Female of this new species highly resembles D. adamsi , but:

1 - Body more rounded;

2 - Depression on anterior margin of clypeus usually deeper;

3 - Tarsi shorter and more slender.

Description of the holotype ♂

General. – Body length 27.5 mm, width 14.9 mm. Large sized, reddish-brown to black; dorsal and ventral surfaces clad with yellowish-gray tomentum.

Head. – Dorsal surface matt, a small tomentous spot on each side; basal part black, clypeus and horns reddish-brown. Eye-canthus narrow and truncate at outer margin, extends at the outermost point of eye, anterior angle rounded. Antenna black, long, with 10 antennomeres; antennal scapus equal in length to antennal club (a little shorter than the antennomeres 2 to 7 combined); antennal scapus with sparse, long hairs on posterior margin. Horns large, “U” shaped; the tip bends inward in dorsal view and upward vertically in lateral view; a large lateral tooth at the middle of outer margin; inner margin with a distinct ridge. Clypeus with a pair of semicircular gaps on sides of lower margin. Ventral surface of head (except for gula) black, coarse, with sparse, long, fulvous hairs. Mentum with a depression in central area; sides deeply lobed; anterior margin of mentum slightly depressed in the middle. Gula glabrous, gradients from reddish-brown to black from base to top. Labial palpi and maxillary palpi simple, reddish-brown.

Pronotum. – Black, clad with yellowish-gray tomentum. Subcircular, strongly convex, widest near middle. Marginal lines complete. Anterior margin distinctly bisinuate; posterior angles extremely rounded. Pronotal band wide, the length about 2/3 of the pronotum length.

Scutellum. – Black. Nearly triangular. Surface clad with yellowish-gray tomentum, except for lateral margins.

Elytra. – Black, clad with yellowish-gray tomentum except for humeral umbone and anteapical umbone. Marginal lines complete. Convex, widest behind the humeral umbone, covers the entire abdomen. Posthumeral emargination indistinct ( Fig. 3 ). Apicosutural angle obtuse (Fig. 10).

Mesepimeron, metepisternum and metepimeron. – Black, clad with tomentum except for marginal lines.

Ventral thoracic surface. – Black, marginal lines of every sternum glabrous. Preprosternum with a small tomentous spot on each side; anterior margin with sparse, long hairs. Postrosternum clad with tomentum and sparse, long hairs; median part with strong, transversal/ diagonal striolae. Anterior part of mesosternum shiny, with sparse, small, rounded punctures; posterior part clad with tomentum, with sparse, long hairs. Metasternum clad with tomentum and sparse, long hairs, except for the disc and mesometasternal process; mesometasternal process triangular, short and small; midline of disc slightly depressed.

Pygidium. – Black. Invisible in dorsal view. Surface clad with tomentum and short hairs except for the marginal lines (Fig. 10). Wide, lower margin arcuate; retracts forward in lateral view.

Abdomen. – Black. Wide and short, sides with sparse, long hairs.

Seven sternites; a longitudinal, shallow groove between sternites 3 to 5; sternite 1 glabrous, extremely narrow; sternites 2 to 5 clad with tomentum except for the marginal lines; sternite 6 with tomentum on sides.

Legs. – Reddish-brown to black. Strong and long. Coxae and ventral surfaces of fermora clad with tomentum. Trochanters glabrous. Procoxae distinctly separated. Protibia with 3 teeth on outer margin and an accrete spine on inner side of apex; underside of protibia apically with a slender spine; ventral surface reddish-brown; the color of dorsal surface gradually changes from reddish-brown to black from the base to the apex. Mesotibia reddish-brown; with a sharp external protrusion at the apical 1/3 of outer margin; 3 sharp teeth on apex; dorsal surfaces coarse, with few hard setae; ventral surfaces smooth. Metatibia resembles mesotibia in texture and color, but the external protrusion and the 3 teeth evidently tiny. Protibia with a spur; meso- and metatibia with two spurs. Tarsi black, strong. Protarsus extremely thick and long; tarsal segment 1 with 2 small, sharp spines apically; eachof tarsal segment2 to 4 with a small, sharpspine on underside apically. Meso- and metatarsi simple, long. Pretarsi simple, developed.

Aedeagus. – As Fig. 11.

Male paratypes. – Body length 18.3-27.4 mm; body width 10.4-14.8 mm. Horns of a single form ( Fig. 17-19 ), and the size proportional to the body size. Some individuals with a pair of tomentous spots on the top of head ( Fig. 5 , 19 ). The length of pronotal band 1/3 to 2/3 of the pronotum length; pronotal band narrow or wide.

Female paratypes. – Body length 17.5-24.8 mm; body width 8.8-13.0 mm. Body black, matt, without tomentum. Dorsal surface of head coarse. Frons and median portion of clypeus distinctly depressed. Anterior margin of clypeus “M” shaped and sharply raised. Antenna simple, shorter and smaller. The shape of mentum similar to that of male. Pronotum less convex and more rounded. Elytra more rounded. Pygidium visible in dorsal view; surface with sparse, long, dark brown to black hairs ( Fig. 9 ). The structure of prosternum and mesosternum more compact. Ventral thoracic surface and femora with sparse, black hairs. Abdomen convex; abdominal ventrite 2 to 5 with sparse, rounded punctures; median portion of abdominal ventrite 6 with dense, sinuous, setiferous striolae; abdominal ventrite 7 slightly protruded. Legs significantly shorter; surface much coarser; all the teeth sharper and more developed; mesotibia with two sharp external protrusions; tarsi short and slender; protrasus and protibia of equal length; meso- and metatarsus shorter than meso- and metatibia; pretarsi simple, small.

Etymology. – The specific epithet is dedicated to the Chinese entomologist Li Chen, who guided me to study the genus Dicronocephalus as my undergraduate thesis in the year 2013.

Distribution. – China: Yunnan.

Natural history. – This species lives in forests with oak trees. From May to July, adults are usually found mating and sucking sap on Quercus sp.

Remarks. – This new species is the fourth member of the D. adamsi group which was proposed by Kurosawa (1986), and was first known just before submitting my graduation thesis on the genus Dicronocephalus in 2013. Unfortunately, specimens obtained in the following decade were insufficient. Until last year, this species were collected in large quantities by local people in Yunnan. It is interesting that during my visit in the Oxford University Museum of Natural History in April 2017, two males and one female ( Fig. 38-44 ) of this new species were found in a box of flower beetles collected from China by the Scots plant collector George Forrest (1873-1932). He had conducted seven expeditions to Yunnan between 1904 and 1932, and sent a large number of plants (including seeds) and animals back to Britain ( Luo, 2005). These three individuals captured about one hundred years ago are the earliest known specimens of the species.

Figures

Fig. 1-3. Dicronocephalus chenliae sp. nov., ♂ holotype. 1. Dorsal view. 2. Ventral view. 3. Oblique view.

Fig. 23-33. Dicronocephalus adamsi from different population. 23-24, 30, 32, 35, 37. Northern population. 27-28, 31, 33 -35. Southern population. 26. Eastern population. 29. Southwestern population.

Fig. 17-19. Dicronocephalus chenliae sp. nov., ♂ paratypes, in oblique view. 17. Large sized. 18. Middle sized. 19. Small sized. Fig. 20-22. Male Dicronocephalus adamsi in oblique view. 20. Large sized. 21 Middle sized. 22. Small sized.

Fig. 4-5. Dicronocephalus chenliae sp. nov., ♂ paratypes. 4. Middle sized. 5. Small sized.

Fig. 6-9. Dicronocephalus chenliae sp. nov., ♀ paratype. 6. Dorsal view. 7. Ventral view. 8. Oblique view. 9. Hair color. Fig. 10-12. Characters of Dicronocephalus chenliae sp. nov.,♂ holotype. 10. Pygidium and elytra.11.Aedeagus.12. Clypeal gap. Fig. 13-16. Characters of Dicronocephalus adamsi. 13.Aedeagus ♂. 14. Clypeal gap ♂. 15 -16. Hair color ♀.

Fig. 38-44. Dicronocephalus chenliae sp. nov., ♂ & ♀ paratypes in OXUM, collected by George Forrest (1873-1932) from China. 38, 41-44. ♂. 39-40. ♀.