Cyclotoma yingjiangensis, Chang & Ren, 2023

Chang, Ling-Xiao & Ren, Guo-Dong, 2023, New and little-known species of the genus Cyclotoma from China (Coleoptera: Endomychidae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 63 (1), pp. 177-185 : 184-185

Cyclotoma yingjiangensis sp. nov.

( Figs 1G–I , 2C , 3C , 4C )

Type material. HOLOTYPE: ♁, CHINA: YUNNAN: ‘China. Yunnan, Dehong, Yingjiang, Mangyunxiang, 2021.VII-VIII, leg. Shao-Xing Chen’ ( NNHMC) . PARATYPES: CHINA: YUNNAN: 1 ♁ 2 ♀♀, same collecting data as holotype ( NNHMC).

Diagnosis. Cyclotoma yingjiangensis sp. nov. resembles C. formosana , C. indiana , C. parvimaculata and C. simianshanensis sp. nov. in the four spots on pronotum and seven spots on each elytron. However, the ventrite 1–3 with black spots can separate it from all these similar species. In addition, C. yingjiangensis sp. nov. differs from C. formosana in antennomeres 1–9 yellowish-brown, club brownish-black (vs. antenna uniformly brownish-black); femora uniformly yellowish brown (vs. femora near apical 1/2 black); from C. indiana in antennomere 5 longer than wide (vs. antennomere 5 subquadrate); from C. simianshanensis sp. nov. in antennomeres 1–9 yellowish-brown, club brownish-black (vs. antenna uniformly brownish-black); antennomere 4 elongate, hardly shorter than antennomere 3 (vs. antennomere 4 distinctly shorter than antennomere 3). Description. Male ( Figs 1G–H , 2C ). Length 6.3–7.5 mm; body 1.2–1.3 times longer than wide; height 3.5–3.8 mm, about 0.5 times as high as long, smooth, strongly shiny. Dorsal surfaces yellowish brown with club of antenna, eyes, scutellum, spots on pronotum and on elytra black; ventral surfaces brown with elytral epipleura yellowish brown.

Antenna 11-segmented with scape long and stout, 4.0 times longer than pedicel; antennomere 2 distinctly longer than wide, antennomere 3 hardly longer than antennomere 4; antennomere 4 distinctly longer than antennomere 5; antennomere 5 longer than wide; antennomeres 6–8 quadrate; club distinctly shorter than remaining antennomeres combined; terminal antennomere twice as long as wide. Maxilla with terminal palpomere elongate, weakly tapering towards apex, truncate apically. Pronotum 1.2–1.4 mm long, 3.1–3.6 mm wide; about 0.4 times as long as wide; anterior and lateral edges very narrowly bordered; disc weakly convex. Pronotal surface polished between punctures, punctation dense and fine. Prosternal process widely separates front coxae, about 0.8 times as wide as longest coxal diameter and narrower than intercoxal process of mesoventrite, widening behind front coxae; sides curved outwardly, rounded at apex. Elytra 5.4–6.5 mm long, 4.9–6.3 mm wide; 1.1 times as long as wide; 4.5–4.6 times longer than pronotum, 1.6–1.8 times wider than pronotum; sides abruptly converging from about half-length towards apex; each elytron with seven black spots of different size and shape (one humeral, three near lateral margin, three sutural); sutural spots with inner margin not touching elytral suture; three lateral spots with outer margin not touching lateral margin of elytra, from dorsal view visible. Humeri moderately prominent; elytral surface polished between punctures, punctation as large as pronotal ones, rather dense and fine. Metasternum with two large transverse black spots and distant from each other.

Ventrite 1 with lines bordering edge of coxal cavity simple ( Fig. 3C ); ventrites 1–3 with two transverse black spots in middle; spots on ventrite 1 largest and gradually smaller on ventrites 2–3; spots with inner margin sometimes touching each other; ventrite 5 weakly concave at apex. Aedeagus ( Fig. 4C ) long, thin, strongly curved, curled at its base; tegmen located at apical 1/3 with large, submembranous, tegminal plate with length reaching base of aedeagus.

Female. Habitus ( Fig. 1I ) similar to males. Elytra with sides gently and widely converging posteriad in apical 1/3.

Etymology. The name refers to the type locality, Yingjiang County, Yunnan Province, China; adjective.

Distribution. China: Yunnan.

Key to the species of Cyclotoma from China (modified and updated from TOMASZEWSKA 2009)

A key to the known species of Cyclotoma was provided by TOMASZEWSKA (2009), including 17 species, except for C. formosana Chûjô, 1938 . Since the type specimens of this species were unavailable for examination and the description of the habitus by CHǙJỏ (1938) is very similar to C. indiana (Chûjô, 1897) , the distinction between these two species was insufficient at that point; therefore, TOMASZEWSKA (2000b, 2009) regarded C. formosana as species incertae sedis.

The first author examined two specimens identified as C. formosana ( Fig. 7 ) in the National Science Museum of Tokyo (NSMT) in 2017. Based on the comparison with the original description and the specimens of C. indiana, Chang considered that there are obvious distinctions between these two species. Therefore, C. formosana is still regarded as a separate species in this study.

1 Elytral markings of irregular shapes; epipleura very wide; body weakly conical. .......................................... ................................. C. conica Tomaszewska, 2000

– Elytral markings more or less regular (round, oval or transverse); epipleura moderately wide; body almost hemisphaerical in shape.............................................2

2 Each elytron with eight spots....................................3

– Each elytron with seven spots...................................4

3 Spots on elytra of different size and shape (second sutural largest, somewhat triangular); antennomere 3 almost 2 times as long as antennomere 4; abdominal ventrite 1 with lines bordering edge of coxal cavity simple. .................... C. nicoleae Tomaszewska, 2000

– Spots on elytra more regular in size and shape (large and very large, rounded or oval); antennomere 3 slightly longer than 4; abdominal ventrite 1 with lines bordering edge of coxal cavity extending posteriorly. ............ ...................... C. octomaculata Tomaszewska, 2002

4 Background of pronotum and elytra of the same colour, four spots on pronotum. ............................................ 5

– Background of pronotum and elytra of different colour, pronotum without spots. ........ C. nigrithorax sp. nov.

5 Antennomere 11 nearly as long as antennomeres 9–10 combined; femora variably coloured. .......................... ....................................... C. formosana Chûjô, 1938

– Antennomere 11 shorter than antennomeres 9–10 combined; femora uniformly coloured......................6

6 Antennomere 4 elongate, hardly shorter than antennomere 3. ...................................................................... 7

– Antennomere 4 distinctly shorter than antennomere 3. ............................................................................... 8

7 Antennomere 5 longer than wide; ventrites 1–3 with black spots. ....................... C. yingjiangensis sp. nov.

– Antennomere 5 subquadrate; ventrite 1 with black spots. .................................. C. indiana (Chûjô, 1897)

8 Three lateral elytral spots visible dorsally; abdominal ventrite 1 with lines bordering edge of coxal cavity extending posteriorly. .................................................. .................... C. parvimaculata Chang & Ren, 2014

– Three lateral elytral spots barely visible dorsally; ventrite 1 with lines bordering edge of coxal cavity simple. .......................... C. simianshanensis sp. nov.

Figures

Fig. 1. Habitus of Cyclotoma spp. nov. A–B – C. nigrithorax sp. nov., male (A ‒ dorsal view; B ‒ lateral view). C – C. nigrithorax sp. nov., female, dorsal view. D–E – C. simianshanensis sp. nov., male (D ‒ dorsal view; E ‒ lateral view). F – C. simianshanensis sp. nov., female (F ‒ dorsal view). G–H – C. yingjiangensis sp. nov., male (G ‒ dorsal view; H ‒ lateral view). I – C. yingjiangensis sp. nov., female (I ‒ dorsal view). Scale bars: 1.0 mm.

Fig. 2. Ventral view of males of Cyclotoma spp. nov. A – C. nigrithorax sp. nov., B – C. simianshanensis sp. nov., C – C. yingjiangensis sp. nov. Scale bars: 1.0 mm.

Fig. 3. Abdomen of Cyclotoma spp. nov. (ventral view). A – C. nigrithorax sp. nov., B – C. simianshanensis sp. nov., C – C. yingjiangensis sp. nov. Scale bars: 1.0 mm.

Fig. 4. Aedeagus of Cyclotoma spp. nov. (lateral view). A – C. nigrithorax sp. nov., B – C. simianshanensis sp. nov., C – C. yingjiangensis sp. nov. Scale bars: 0.5 mm.

Fig. 7. Specimens identified as C. formosana Chûjô, 1938. A–B – male (A ‒ dorsal view; B ‒ ventral view). C–D – female (C ‒ dorsal view; D ‒ ventral view). E–F – specimen labels (E ‒ male; F ‒ female). Scale bars: 1.0 mm.