Chlaenius (Chlaenioctenus) langsonensis Kirschenhofer, 2008 new subgenus assignment

(Figs. 19, 25, 31, 37)

Chlaenius (Ocybatus) langsonensis Kirschenhofer, 2008: 17

Specimens examined (total 1 specimen). Holotype, male (MNHU), “ Tonkin, Montes Mauson, April. Mai 2−3000, H. Fruhstorfer ”/ “ Chlaenius (Ocybatus) langsonensis sp. n. det. Kirschenhofer 2008 ”.

Description. Kirschenhofer (2008: 17) gave a quite detailed description. We add the following here: Genae glabrous, tumid, as long as half of eyes in dorsal view. Pronotum (Fig. 25) with lateral margin straight before posterior angle. Elytral with intervals (Fig. 31) convex, glabrous medially, with a row of pubescence laterally; each elytron with a round yellow spot slightly behind the middle, covering intervals 4−8. Claws (Fig. 37) curved, with 6−7 long teeth.

Remarks. Bates (1892) erected subgenus Chlaenioctenus for claws with teeth, a character unique within the genus Chlaenius . This subgenus is similar to subgeneus Ocybatus Laferté-Sènectére in having widened labial palpi and two yellow spots on elytra, but differs from the latter in having rounded shoulders (hind wings reduced) in addition to pectinate claws. After examined the holotype of C. langsonensis with pectinate claws and rounded shoulders, we assignate this species to subgenus Chlaenioctenus from Ocybatus herein.

Chlaenius langsonensis is most similar to C. schillhammeri Kirschenhofer in having yellow spot slightly behind the middle, femora bicolored and pronotal lateral margin nearly straight before posterior angle (Fig. 25; also see Fig. 34 in Liu et al. 2010), but differs from the latter in antennomere 1 brown (antennomere 1 black in C. schillhammeri), genae strongly tumid (Fig. 19) (genae slightly tumid in C. schillhammeri), and pronotal disc (Fig. 25) more coarsely punctate (less coarsely in C. schillhammeri). Their difference of external characters is quite minor, and study on their male genitalia is necessary when male of C. schillhammeri is available in the future.

C. langsonensis also could be confused with C. eneides in having elytral yellow spot slightly behind the middle and femora bicolored, but differs from the latter in having pronotal lateral margin (Fig. 25) straight before posterior angle (lateral margin sinuate in C. eneides, Fig. 24).