Viridagonum Lassalle, 2015

Viridagonum Lassalle, 2015 View in CoL

142 Type species Viridagonum lumawigi Lassalle, 2015 by monotypy.

Observations. The discovery of new species makes it necessary for us to redefine the generic characters of Viridagonum Lassalle, 2015 . The original diagnosis of genus lists the following characters: a single frontal seta behind the eye; no pronotal anterolateral seta (but with five setae are present on each side in one female of V. azureoviride n. sp.); mentum and submentum bisetose; scutellar striole present; scutellar seta at the base of stria 1 (occasionally there are two scutellar pores in V. lumawigi , one pore in V. azureoviride n. sp.); no discal setae (at a more accurate observation, in V. lumawigi there are 3-5 small pores with short setae in the third interval, close to stria 3); elytra with very reduced sculpture; epipleura “crossed”; antennal article 3 twice as long as 4; profemur and metafemur with a few setae on the dorsal side, none on the ventral side; profemur clearly furrowed on the superior face; 3 first segments of the male protarsi wide, rectangular and slightly asymmetrical; article 4 of all tarsi strongly bilobed, those of the meso- and metatarsi slightly asymmetrical; the greatest length of the lobe of the tarsus is on the inner side; gonapophysis with only 2 small setae on the basal segment; apical segment spineless, with 2 small bristles on one side and a longer one on the other, the foramen with 1 or 2 setae.

All of these characters are shared also by our new species, except the reduced elytral sculpture; in fact the elytra are completely punctate and pubescent, with an evident isodiametric microsculpture on the intervals. We have checked all of these characters, noting that in both species the profemur is not so clearly furrowed, but has a very superficial, hardly visible furrow.

One of the important characters not mentioned in the original description is the occurrence of microbristles under the onychium; in the other genera of Chlaeniini and in some specimens that we have checked of all the known subgenera of Chlaenius , a double row of spinules or, in some rarer cases, thinner but still very evident bristles are clearly evident in the lower part of the onychium. The only exception is subgenus Dacnochlaenius Alluaud, 1919 which has onychium without bristles, but it is a completely different group. Furthermore, V. lumawigi and V. azureoviride n. sp. have black femurs and tarsi with yellowish tibiae with black apex and base, but very few species among over 1000 species of Chlaeniini have this type of color pattern: C. (Lissauchenius) bifenestratus Klug, 1832 , C. (Chlaenites) inderiensis (Motschulsky, 1850) , C. (Chlaenius) gonioderus ssp. nigrofemoralis Basilewsky, 1949 (the typical form has pale femurs) and a few other cases. The tarsomere 4 is emarginated in both species of Viridagonum : the subgenus Lithochlaenius Kryzhanovskij, 1976 has protarsomere 4 emarginated, especially in the male, but it has the basal margin of elytra incomplete, while it is complete in Viridagonum lumawigi and azureoviride . Furthermore, in Lithochlaenius the setae under the onychium are clearly visible, even if thin.

In addition to the three previous characters, rare or unusual for the Chlaeniini , Viridagonum lumawigi and V. azureoviride share a similar habitus (not considering the elytral punctuation) and an extremely similar aedeagus structure, with short and robust median lobe and strongly downturned apex

( Figs 4-5 View Figs 4-5 ); furthermore, both are from the same island of the Philippines (Mindanao).