Synchroa elongatula 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 : 24-25

Synchroa elongatula Nikitsky, 1999

Figs 3I , 4E, K , 5I –J, Q , 6M–N

Synchroa elongatula Nikitsky, 1999: 476 .

Diagnosis

This species resembles Synchroa melanotoides in pronotal structure, with lateral sides margined in posterior one-third to one-fourth, but it can be distinguished by its blackish brown antennae and legs; elongate and slender elytra; prosternal process narrowed apically; aedeagus: paramere wider, with lateral sides subparallel or sinuate. It is also similar to S. formosana , but differs in partially margined pronotum; aedeagus: basal part of median lobe narrower.

Material examined

LAOS: 1 ♂, Ban Satuei village env ., 20 ° 12′ N, 103°50′ E, Mt. Phu Pane , 1200–1900 m, Huaphanne prov. [= Houaphanh prov. in NE Laos], 1–20 May 2014, St. Jakl and Lao leg. ( OKZC).

Supplementary description of male from Laos ( Fig. 3I )

MEASUREMENTS. Length: 11.50 mm (10.00–11.00 in type series); width: 3.00 mm.

HEAD. Ratio of eye diameter to interocular space 1.0: 1.6 (1.41–1.49 in type series). Antennomere XI ca 3.0 times as long as maximum width. Length ratio of antennomeres as follows: 1.65: 1.00: 2.10:1.95: 1.50: 1.50: 1.40: 1.50: 1.55:1.50: 2.20.

PRONOTUM. Ca 1.5 times wider than length, ca 1.7 times as wide as head.

ELYTRA. Ca 3.0 times as long as maximum width. Seven faint traces of striae in each elytron from dorsal view, stria I fused with II ( Fig. 4E ), gradually shortened outwards. Prosternal process long, margined laterally, rounded and narrowed apically; length behind procoxae longer than width between procoxae. Mesoventrite with shallow, oval mesoventral cavity, moderately punctate.Abdominal ventrite V truncate, with lateral sides rounded ( Fig. 4K ); sternite VIII concave in middle of apical edge, forming two roundly angular lobes on both sides, densely pubescent apically ( Fig. 5J ); sternite IX without spiculum gastrale on apical edge ( Fig. 5Q ); tergite VIII without median strut on apical edge, rounded apically, densely pubescent apically ( Fig. 5I ); tergite IX and X completely fused, rounded apically, densely pubescent on apical edge ( Fig. 5Q ).

AEDEAGUS ( Fig. 6M–N ). Lanceloate, basal piece curved dorsally, lateral sides narrowed basically. Parameres narrowly separated apically and with a groove in dorsal median part, lateral sides distinctly widened in middle, length ca 3.2 times maximum width. Median lobe elongate, tapered, strongly narrowed apically in apical half.

Notes

In the original description, this species was mentioned as having striae only in the apical part of the elytral suture. However, we discovered extremely indistinct elytral striae on this specimen. Together with our analysis of this character, it is possible that the elytral striae of the type series are too faint to observe or this character varies from absent to indistinct within this species. On the other hand, although most of the characters are in accordance with the original description, the parameres of this specimen are different from the illustration given in Nikitsky (1999) by its distinctly widened lateral sides and narrower dorsal groove, which implies that it could belong to another taxon new to science. Considering the insufficient material, intraspecific variation within other species and geographic distribution, we herein regard this specimen as representing a variation of S. elongatula instead of giving it a new taxonomic status.

Distribution

Vietnam; Laos, new record.

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.