Synchroa chinensis Nikitsky, 1999

Hsiao, Yun, Ondřej Konvička & Chiun-Cheng Ko, 2018, The world fauna of Synchroidae Lacordaire, 1859 (Coleoptera, Tenebrionoidea, Synchroidae), European Journal of Taxonomy 407, pp. 1-33 : 19-21

Synchroa chinensis Nikitsky, 1999

Figs 3E–F , 4C, I , 5E–F, O , 6J–K , 7

Synchroa chinensis Nikitsky, 1999: 478 .

Diagnosis

This species resembles Synchroa formosana Hsiao, 2015 by the unmargined lateral sides of pronotum, but can be distinguished by the following combination of characters: blackish-brown body and reddishbrown to dark brown antennae, apical maxillary palpomere and tarsi; aedeagus: more slender paramere and narrower basal part of median lobe.

Material examined

CHINA (mainland): 2 ♂♂, Tajbashan Range, Houzhenzi vill. env., Shaanxi [prov.], 33°55′ N, 107°49′ E, 1900 m, 15 Aug.–15 Oct. 1999, collector unknown ( OKZC) ; 1 ex., 15 km south of Shouman, Daba Shan Mts , Shaanxi Prov., 32°08´N, 108°37´E, 1800–2100 m, 25 May–14 Jul. 2000, A. Plutenko leg. ( OKCZ) ; 1 ♀, Lueyang , Shaanxi prov., 23–30 May 2009, E. Kučera leg. ( MAIC) ; 1 ♀, Qingchenghou Shan Mts, 70 km NW of Chengdu , Sichuan prov., 1500 m, 6–13 Aug. 2010, S. Murzin leg. ( OKZC) ; 4 ♂♂, 1 ♀, Nanping (Jiunaigou) [= Jiuzhaigou ] env., Sichuan prov., 1700 m, 33.2435 N, 104.2383 E, 4–20 Jul. 2012, M. Murzin leg. ( OKZC) ; 4 ♂♂, Lueyang env., Shaanxi [prov.], 21 Jun.–6 Jul. 2014, E. Kučera leg. ( OKZC) ; 1 ♀, 100 km S of Jayuguan, Tulai env., NW of Gansu [prov.], 4200 m, 10 Jul. 2014, V. Patrikeev leg. ( OKZC) .

Redescription

Colour. Body and legs blackish-brown. Antennae, apical maxillary palpomere and tarsi reddish brown to dark brown.

Male ( Fig. 3E )

MEASUREMENTS. Length: 9.25–13.25 mm; width: 2.25–3.50 mm.

BODY. Elongate, slightly flattened, elytra rather strongly narrowed posteriorly, covered with yellowish, elongate and decumbent setae.

HEAD. Eyes lateral, large, emarginate in front of antennal insertions, ratio of eye diameter to interocular space 1.0: 1.3–1.5. Antennae filiform, when directed backwards exceeding the humeri of elytra. Scape cylindrical, wider than other antennomeres, pedicel short, antennomere III–XI somewhat clavate, XI longest, length ca 4.3–5.6 times maximum width. Length ratio of antennomeres as follows: 1.50: 1.00: 2.25:2.10: 1.85: 1.95: 1.95: 1.90: 1.85:1.60: 2.75. Apical maxillary palpomere securiform, apical margin moderately rounded, terminal angle somewhat obtuse. Surface lustrous, densely and coarsely punctate; interspaces slightly narrower than puncture diameter.

PRONOTUM. Truncate anteriorly, bisinuate posteriorly, with obtuse median lobe, width ca 1.5 times length, ca 1.6–1.7 times as wide as head. Lateral sides slightly rounded and strongly narrowed in anterior twothirds toward head, subparallel in posterior one-third, unmargined. Anterior angle rounded; posterior angle rectangular and obtuse. Disc slightly flattened medially, surface lustrous, densely and coarsely punctate; spaces between punctures smaller than puncture diameter. Scutellum with width ca 1.6–1.7 times length.

ELYTRA. Elongate, narrowed posteriorly, apex rounded, as wide as pronotal width at humeri, length ca 2.4–2.7 times width, surface lustrous. Disc covered with oval punctures, denser in lateral and basal part; interspaces wider than puncture diameter. Eight faint traces of striae in each elytron from dorsal view, stria I fused with II ( Fig. 4C ), gradually shortened outwards, only four traces of elytral striae present or extremely indistinct in some specimens. Prosternum before procoxae about as long as shortest diameter of procoxae. Prosternal process long, margined laterally, rounded and narrowed apically; length behind procoxae longer than width between procoxae. Width between procoxae ca 0.3 times transverse coxa diameter. Mesoventrite with shallow, oval mesoventral cavity, moderately punctate. Abdominal ventrite V subtruncate, with lateral sides somewhat rounded ( Fig. 4I ); sternite VIII concave in middle of apical edge, forming two roundly angular lobes on both sides, densely pubescent apically ( Fig. 5F ); sternite IX without spiculum gastrale on apical edge ( Fig. 5O ); tergite VIII without median strut on apical edge, rounded apically or slightly emarginate in middle, moderately pubescent apically ( Fig. 5E ); tergite IX and X completely fused, rounded apically, densely pubescent on apical edge ( Fig. 5O ).

LEGS. Slender. Tarsomeres simple, tarsal formula 5-5-4. The longest spur of hind tibiae ca 0.3 times as long as first tarsal segment; length ratio of tarsomeres as follows: 2.35: 1.00: 0.55: 0.85 (measured without claws). Claws simple.

AEDEAGUS ( Fig. 6J–K ). Lanceloate, basal piece curved dorsally, lateral sides narrowed basically. Parameres narrowly separated apically and with a groove in dorsal median part, lateral sides slightly sinuate, moderately narrowed apically, abruptly strongly narrowed at apex, length ca 3.5–3.9 times maximum width. Median lobe elongate, tapered, strongly narrowed apically in apical half.

Female ( Fig. 3F )

MEASUREMENTS. Length: 9.50–13.00 mm (11.50 in holotype); width: 2.25–3.25 mm.

BODY. Similar to males.

HEAD. Eyes smaller than in male, ratio of eye diameter to interocular space 1.0: 1.2–1.5 (1.49 in holotype). Antennae shorter in male, when directed backwards extending the posterior edge of pronotum, antennomere XI ca 2.9 times as long as maximum width. Length ratio of antennomeres as follows: 2.20: 1.00: 2.10: 1.90: 1.85:1.90: 2.00: 1.90: 1.80: 1.80:2.40.

PRONOTUM. Ca 1.5–1.6 times wider than length (1.5 in holotype), ca 1.5–1.6 times as wide as head.

ELYTRA. Slightly wider than in male, as wide as pronotal width at humeri, length ca 2.4–2.5 times width (2.6–2.7 in holotype).

OVIPOSITOR. Paraproct elongate, ca 2.6–3.0 times length of coxite, sides straight and subparallel; proctiger subtruncate.

Remarks

In the original description, Nikitsky (1999) provided as diagnostic character the presence of faint striae only in apical part and illustrated it. This character together with the posteriorly narrowed elytra has been used in Hsiao (2015) and Hsiao et al. (2016) as comparative information to distinguish S. formosana .

However, in the course of this study we discovered that the elytral striae are variable, noticeable on the entire elytron or even indistinct in some specimens. Elytral striae of synchroids are vague and difficult to observe accurately if the specimen is dry and not dissected, consequently it is possible that the elytral striae of the holotype have not been not observed correctly.After examining a large number of specimens, the shape of the elytra appears proved to be variable as well (length ca 2.4–2.7 times width). Therefore, we eliminate both inappropriate characters from the diagnosis and re-diagnose the differences between the species (see the detail in diagnosis and key).

Distribution

China (Sichuan, Shaanxi, Gansu) ( Fig. 7 ).

Notes

This species was described based on a single female from Qingchengshan in Sichuan Province. On the basis of new available specimens S. chinensis is confirmed as a valid species, distributed in Shaanxi and Gansu province.

Figures

Fig. 3. Habitus, dorsal view. A–B. Synchroa punctata Newman, 1838. C–D. S. melanotoides Lewis, 1895. E–F. S. chinensis Nikitsky, 1999. G–H. S. formosana Hsiao, 2015. I. S. elongatula Nikitsky, 1999. J–K. Synchroina tenuipennis Fairmaire, 1898. L. Thescelosynchroa pangu (Hsiao, Li, Liu & Pang, 2016) gen. et comb.nov.A, C, E, G, I, J, L = ♂. B, D, F, H, K = ♀. Scale bars: 5.0 mm.

Fig. 4. Elytron and abdominal ventrite V. A–F. Elytron. G–L. Abdominal ventrite V of ♂♂. — A, G. Synchroa punctata Newman, 1838. B, H. S. melanotoides Lewis, 1895. C, I. S. chinensis Nikitsky, 1999. D, J. S. formosana Hsiao, 2015.E, K. S. elongatula Nikitsky, 1999. F, L. Synchroinatenuipennis Fairmaire, 1898. Scale bars: 0.5 mm.

Fig. 5. Abdominal sternite VIII–IX and tergite VIII–X of ♂♂. A, C, E, G, I, K. Abdominal tergite VIII. B, D, F, H, J, L. Abdominal sternite VIII. M–R. Abdominal sternite IX, and fused tergite IX and X. — A–B, M. Synchroa punctata Newman, 1838. C–D, N. S. melanotoides Lewis, 1895. E–F, O.S.chinensisNikitsky, 1999.G–H,P.S.formosana Hsiao,2015.I–J,Q. S.elongatulaNikitsky,1999. K–L, R. Synchroinatenuipennis Fairmaire, 1898. Scale bars: 0.5 mm.

Fig. 6. Aedeagus. A–E. Synchroa punctata Newman, 1838. F–I. S. melanotoides Lewis, 1895. J–K. S. chinensis Nikitsky, 1999. L. S. formosana Hsiao, 2015. M–N. S. elongatula Nikitsky, 1999. O–P. Synchroina tenuipennis Fairmaire, 1898. Q–R. Thescelosynchroa pangu (Hsiao, Li, Liu & Pang, 2016) gen. et comb. nov. — A–C, F–G, J, L–M, O, Q. Dorsal view. D–E, H–I, K, N, P, R. Lateral view. Scale bars: 0.5 mm.

Fig. 7. Distribution map of Synchroa chinensis Nikitsky, 1999 from China.