Megistophylla keithi Wang & Gao, new species

(Figs. 20–36)

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Type material. Holotype, ♂ (MYNU): CHINA: Yunnan Province / Dehong, Yingjiang County / Xima Village, 2019.VI / Wei-Zong Yang leg. Paratypes, 2 ♂♂ (MYNU, CLYL): same data as for the holotype.

Description of the holotype (Figs. 20–36). Length 20.2 mm, width 10.3 mm. Body oval-elongate, strongly convex (Fig. 22).

Color: The whole body dark reddish-brown.

Head: Clypeus subtrapezoidal, as wide as frons; anterior margin reflexed, distinctly incurve at middle, surface with dense, deep punctures, fronto-clypeal suture complete and straight (Fig. 23). Frons densely punctate; punctures mostly connected to each other; compound eyes comparatively large, canthus with several setae, head approximately 0.56 times wider than interocular. Frontal carina distinctly raised. Vertex largely punctate anteriorly and setiferous laterally. Antennae with 10 antennomeres, antennal club composed of 8 antennomeres, strongly curved outwards, antennal club more than 4.0 times longer than antennomeres 1–2 combined; antennomere 1 twice as long as antennomere 2; antennomere 3 consist of the basal handle and extended blade (Fig. 24).

Mouthparts: Labrum strongly depressed at middle; ventral side setiferous; dorsal side with dense short setae along depression; both sides triangular-shaped (Figs. 32, 33). Mandible with wrinkled molar lobe and rounded notch in incisor lobe (Fig. 34). Distal galea of maxilla with 6 sharp teeth (Fig. 35). Mentum distinctly bilobate at apical half and formed a small notch at middle of anterior margin; each paraglossa with 6–7 setae near base of labial palpus (Fig. 36).

Pronotum glabrous and punctate, sparser around posterior corners; with a smooth middle longitudinal line on posterior half. Anterior margin complete. Both sides flat in dorsal view, lateral margins crenulate and setiferous; posterior margin bear some short setae laterally on lateral punctures. Anterior angles obtuse, posterior angles obtuse and rounded.

Scutellum: Scutellum glabrous and smooth, with several or without punctures (Fig. 25).

Elytra: Surface of elytra deep and dense punctate, slightly wrinkled beside sutural costa. Sutural costa developed, indistinct on anterior 1/3. Epipleuron disappears before hind angles; bearing a row of long soft setae before apex.

Pygidium: Apex broadly rounded, surface with deep, sparse, inhomogeneous punctures (Fig. 26).

Venter: Ventral thorax setiferous. Entire surface of metepisternum and metepimeron covered with dense and long yellow hair; metepisternum narrow. Abdominal sternite 1and posterior sternite 2 with dense punctures and dense shot setae; middle of abdominal sternites 3 and 4 sparsely punctate, punctures moderately dense on lateral sides; posterior half of abdominal sternite 5 with long soft setae; sternite 6 with dense punctures and short setae (Fig. 21). Surface of propygidium with dense rugose punctures.

Legs: Meso- and metafemora setiferous ventrally. Protibia tridentate, terminal tooth long and crooked, middle tooth acute, basal tooth nearly right angle, anterior inner margin with a row of long setae, inner spur long and sharp; ventral side with a longitudinal sharp ridge. Apex of mesotibia and metatibia widened, inner surface with a row of strong setae; apex of mesotibia with two equal length spurs; apex of metatibia with two unequal length spurs. Outer surface of meso- and metatibia with a transverse complete transverse carina; setae on carina longer than those on apex. Inner margin of dorsal surface of metatibia with 3 teeth. Each pro-, meso- and metatarsal claw with a tooth vertically medially.

Aedeagus: Phallobase shorter than parameres and connected to each other by wrinkle membranous area on dorsum; anterior 1/4 of phallobase reduced. Parameres slender with two long, symmetric branches; branches curved about 45° downward at middle; posterior half of left and right branch connected to each other by membrane ventrally, with dense, irregular longitudinal sulcus dorsally and laterally; lateral sides of posterior half of two branches with a long depression at middle laterally; anterior half of two branches separated; apex crooked (in lateral view) and bloated, rounded (Figs. 27–30). Endophallus with two long temones apophysis nearly parallel at dorsum, and with epithelium bears sparsely punctate a sensillae at middle.

Variability. Paratypes differ in size (body length 16.8–19.8 mm and width 9.1–10.0 mm).

Female. Unknown.

Chinese name. DZƶDzẅm

Differential diagnosis.Based on the antennal club composed of eight antennomeres and body length, Megistophylla keithi new species shares similarities with two congeners: M. andrewesi and M. lamdongensis Keith, 2020 (Keith 2020; Li et al. 2016). Megistophylla keithi new species can be distinguished from M. andrewesi by its darker body color (Figs. 24, 41), a longer clypeus, antennomere 2 lacking a spike, antennomere 3 not thickened (Figs. 20–22, 37–39), and displaying slender male genitalia (Figs. 29, 30, 47, 48). Furthermore, it deviates M. lamdongensis due to its shorter antennal club, pronouncedly curved sides of pronotum (Fig. 20; Keith 2020, fig. 5), and slender male genitalia (Figs. 29, 30; Keith 2020, figs. 6, 7).

Etymology. The new species is named after Denis Keith, a renowned scarab researcher from France, who graciously provided us with his taxonomic articles. These articles have proved to be of significant assistance to our study.

Distribution. Known only from the type locality in Yingjiang County, southwestern region of Yunnan Province, China.