Geostiba (Tropogastrosipalia) gibberiventris, Assing, 2017

Assing, Volker, 2017, A revision of Geostiba of the West Palaearctic region. XXV. New species from Georgia and Greece, and additional records (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 49 (2), pp. 1093-1106 : 1099-1101

Geostiba (Tropogastrosipalia) gibberiventris nov.sp. ( Figs 11-15 , 18 , Map 1 )

T y p e m a t e r i a l: Holotype 3: "N 42°26'40 E 44°55'57 (19), GG Zentral-Kaukasus, Gudani - Zhinvali 1200 m, Brachat & Meybohm 19.7.2015 / Holotypus 3 Geostiba gibberiventris sp. n. det. V. Assing 2017 " (cAss). Paratypes: 13 [without apex of abdomen], 3♀♀: same data as holotype (cAss, MNB).

E t y m o l o g y: The specific epithet is an adjective composed of the Latin noun gibber (tubercle) and the adjectival ending -ventris (of the abdomen). It alludes to the presence of median tubercles on the male tergites III and IV, one of the characters distinguishing the new species from the geographically close G. tiflisensis .

D e s c r i p t i o n: Body length 2.1-2.8 mm; length of forebody 0.9-1.1 mm. Coloration: head brown to dark-brown; pronotum pale-brown to reddish-brown; elytra yellowish to yellowish-brown; abdomen blackish, with tergite II (rarely also III and IV) and the apex (posterior margin of tergite VII, segments VIII-X) paler; legs yellow; antennae dark-yellowish to pale-reddish, with the basal 2-3 antennomeres pale-reddish. Head, pronotum, and elytra with shallow to distinct microsculpture ( Fig. 11 ). Posterior margin of abdominal tergite VII without palisade fringe.

3: pronotum ( Fig. 11 ) distinctly modified, weakly oblong, approximately 1.05 times as broad as long and 1.2 times as broad as head, posterior margin produced, broadly and weakly concave in the middle; elytra ( Fig. 11 ) with relatively weakly elevated sutural carinae extending along distinctly more than anterior half of suture, with moderately fine and rather dense non-granulose punctation, disc very shallowly impressed; abdominal tergites III and IV ( Fig. 12 ) each with a median tubercle; tergite VII ( Figs 13-14 ) with a short, narrow (antero-dorsal view), and suberect median spine at posterior margin; median lobe of aedeagus ( Fig. 18 ) 0.24 mm long and with nearly straight and slender cristal process.

♀: pronotum approximately as long as broad, posterior margin broadly and weakly convex in the middle; spermatheca ( Fig. 15 ) not distinctive.

I n t r a s p e f i c v a r i a t i o n: In the (small) male paratype, the pronotum is as broad as long and posteriorly broadly truncate in the middle, the sutural carinae of the elytra are very weakly pronounced (nearly obsolete), the median tubercle on tergites III and IV are present, but not very distinct, and the spine on tergite VII is reduced to a weakly elevated tubercle.

C o m p a r a t i v e n o t e s: Geostiba gibberiventris is distinguished from the geographically close G. tiflisensis particularly by the posteriorly concave or truncate male pronotum, indistinctly impressed elytra with sutural carinae and non-granulose punctation, modified male tergites III and IV, and by the narrower, less broad-based spine (antero-dorsal view) on the male tergite VII. It differs from G. svanetica by the paler coloration of the head, the presence of microsculpture on the elytra, the shape of the male pronotum, longer and less elevated sutural carinae, and the shape of the cristal process.

In order to account for both G. gibberiventris and G. svanetica , the key in ASSING (2009)

is modified as follows:

34 Distribution: South Armenia ( Map 1 ). Male pronotum large in relation to head, in large male distinctly oblong, 1.10-1.15 times as long as wide, posteriorly distinctly projecting caudad and covering scutellum, posterior margin in the middle with distinctly concave excision; elytra with short, narrow, and weakly elevated sutural carinae ( ASSING 2005a: figure 71); abdominal tergite VII with rather long, slender, apically acute, suberect process ( ASSING 2005a: figures 72-73); aedeagus as in PACE (1983: figures: 6-7) ................................................................................ G. khnzoriani PACE

- Distribution: Greater Caucasus (North Georgia). Male sexual characters different ........ 34a

34a Head reddish, of similar coloration as pronotum. Male elytra without sutural carinae, with granulose punctation, and with pronounced impression on disc; posterior margin of male pronotum obtusely pointed in the middle; abdominal tergites II and III unmodified. Cristal process of aedeagus stout and sinuate, somewhat fin-shaped ( Fig. 16 ). Georgia: Mtskheta-Mtianeti ( Map 1 ) ................................................ G. tiflisensis PACE

- Head moderately to distinctly darker than pronotum. Male elytra with sutural carinae, with non-granulose punctation, and with indistinct impression on disc; posterior margin of male pronotum convex, truncate, or concave in the middle; abdominal tergites II and III each with median tubercle ( Figs 8, 12 ). Cristal process of aedeagus slender and (nearly) straight ...............................................................................................................34b

34bElytra without microsculpture. Male pronotum ( Fig. 7 ) practically unmodified, approximately 1.1 times as broad as long, and with smoothly and broadly convex posterior margin; cristal process of aedeagus ( Fig. 17 ) very slender. Georgia: Svaneti ( Map 1 )................................................................................................. G. svanetica nov.sp.

- Elytra with more or less distinct microsculpture. Male pronotum ( Fig. 11 ) at least as long as broad, posteriorly moderately produced, and with truncate to concave posterior margin; cristal process of aedeagus ( Fig. 18 ) less slender. Georgia: Mtskheta-Mtianeti ( Map 1 )........................................................................................... G. gibberiventris nov.sp

D i s t r i b u t i o n: The type locality is situated on the east side of the Pshavskaya Aragvi river valley in Mtskheta-Mtianeti, North Georgia ( Map 1 ). The specimens were sifted from leaf litter at an altitude of 1200 m (MEYBOHM pers. comm.).

Figures

Map 1: Distributions of the species of the subgenus Tropogastrosipalia in the Caucasus region, based on examined records: G. svanetica (black diamond); G. gibberiventris (white diamond); G. tiflisensis (black circles); G. artvinensis (white circles); G. pontica (black square); G. solodovnikovi (black star); G. priva (white square); G. khnzoriani (black triangles).

Figs 7-15: Geostiba svanetica nov.sp. (7-10) and G. gibberiventris nov.sp. (11-15): (7, 11) male forebody; (8, 12) anterior portion of male abdomen; (9, 13) male tergites VI-VII in antero-dorsal view; (10, 14) male tergites VII-VIII in lateral view; (15) spermatheca. Scale bars: 7-14: 0.2 mm; 15: 0.1 mm.

Figs 16-18: Median lobe of aedeagus in lateral view of Geostiba tiflisensis (16), G. svanetica nov.sp. (17), and G. gibberiventris nov.sp. (18). Scale bar: 0.1 mm.