Geostiba (Sibiota) tuberifera, Assing, 2009

Assing, V., 2009, A revision of Geostiba of the Western Palaearctic region. XIX. New species from Turkey and Iran and additional records, with an updated key and a catalogue of the species of the Eastern Mediterranean, the Caucasus, and adjacent regions (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 41 (2), pp. 1191-1246 : 1212-1215

Geostiba (Sibiota) tuberifera nov.sp. ( Figs 62-69 )

Holotype Ƌ: "N 37°19'31 E 036°42'17, TR Kahramanmaras, SW Imali, 1050-1100 m, 21.4.2009, Brachat & Meybohm (25) / Holotypus Ƌ Geostiba tuberifera sp. n. det. V. Assing 2009" (cAss) . Paratypes: 3♀♀: same data as holotype (cAss).

D e s c r i p t i o n: Very small species, body length 1.9-2.2 mm. Habitus as in Fig. 62 . Coloration: whole body uniformly yellowish.

Head weakly oblong; punctation extremely fine, barely noticeable; surface glossy, with or without extremely shallow traces of microreticulation. Eyes reduced to minute oblong rudiments without ommatidia and pigmentation. Antennae distinctly incrassate apically, antennomere X approximately twice as wide as long.

Pronotum weakly transverse, approximately 1.1 times as wide as long and 1.1 times as wide as head; posterior margin truncate in the middle ( Fig. 63 ); punctation extremely fine, barely noticeable; surface with distinct, but shallow microsculpture.

Elytra with pronounced sexual dimorphism, depressed and with fine punctation in both sexes, approximately 0.55 times as long as pronotum ( Fig. 63 ); microsculpture more or less pronounced. Hind wings completely reduced. Mesotarsomeres IV and V not distinctly fused.

Abdomen distinctly wider than elytra ( Fig. 62 ); punctation sparse and fine; microsculpture shallow, but distinct; tergites III, IV, and VII with sexual dimorphism; posterior margin of tergite VII without palisade fringe; posterior margin of tergite VIII convex in both sexes ( Fig. 67 ).

Ƌ: elytra with pronounced tubercle on either side of scutellum, lateral margins sharply angled in the middle; abdominal tergite III with pronounced, tergite IV with weaker median tubercle ( Fig. 64 ); tergite VII posteriorly with short, stout, and smooth median tubercle ( Figs 64-65 ); posterior margin of sternite VIII convex; median lobe of aedeagus as in Fig. 68 .

♀: posterior margin of sternite VIII weakly concave in the middle ( Fig. 67 ); spermatheca as in Fig. 69.

E t y m o l o g y: The specific epithet (Latin: carrier of a bump) alludes to the shape of the process of the male abdominal tergite VII, one of the characters distinguishing this species from similar congeners.

C o m p a r a t i v e n o t e s: Based on the similar external morphology, the male secondary sexual characters (modifications of the elytra and abdominal tergites III, IV, and VII) and the shapes of the aedeagus and the spermatheca, G. tuberifera undoubtedly belongs to the G. confusa group, which previously included six species: G. confusa ASSING 2001 (Adana: Karatepe), G. tuberosa ASSING 2004 (Kahramanmaraş) , G. bigibbera ASSING 2005 (Kahramanmaraş) , G. gibbera ASSING 2005 (Kahramanmaraş) , G. spinosula ASSING 2007 (Osmaniye) , and G. occaecata ASSING 2004 (Gaziantep) . It is distinguished from the geographically close species by the primary sexual characters and additionally as follows:

from G. confusa by the shallower microsculpture of the elytra and the abdomen, the nonfused mesotarsomeres IV and V, the more pronounced tubercles on the male elytra and on the male abdominal tergites III and IV, the laterally sharply edged male elytra, and the shape of the process of the male tergite VII ( G. confusa : distinctly longer, more slender, and more acute);

from G. tuberosa by much smaller body size, paler coloration, the much less pronounced microsculpture of the forebody, the different position of the tubercles on the male elytra ( G. tuberosa : slightly behind the middle of suture), the sharply edged lateral margins of the male elytra, the different shape of the elytra ( G. tuberosa : lateral margins distinctly diverging posteriad), the presence of tubercles on the male tergites III and IV, and the presence of a median process on the male tergite VII ( G. tuberosa : pair of carinae);

from G. bigibbera by slightly smaller size, smaller and more oblong eye rudiments, the less pronounced and more widely separated tubercles on the male elytra, the more pronounced tubercle on the male tergite III, the less pronounced microsculpture on the male tergites III and IV ( G. bigibbera : tubercles and surrounding tergal area with distinct microsculpture), and by the much shorter, stouter, less erect, and less acute process of the male tergite VII;

from G. gibbera by slightly smaller body size, smaller and more oblong eye rudiments, much less pronounced microsculpture of the elytra, shorter elytra, less pronounced lateral carinae on the male elytra, more pronounced tubercles on the male tergites III and IV, and by the much shorter, stouter, less erect, and less acute process of the male tergite VII;

from G. spinosula by the presence of distinct tubercles on the male elytra, the more pronounced tubercles on the male tergites III and IV, and by the distally less dilated capsule of the spermatheca.

The evidently close relationship of the species of the Geostiba confusa group is supported by the similar morphology of the primary sexual characters, the similar external morphology, the similar ecology, the fact that they all are distributed in the same region, and above all by the following, undoubtedly synapomorphic character states: presence of tubercles on the male elytra (reduced in G. occaecata and G. spinosula ), the sharply edged laterally margins of the elytra (absent or indistinct in G. tuberosa , G. occaecata , and G. confusa ), the presence of tubercles or elevations on the male abdominal tergites III and IV (exception: G. tuberosa ), and the presence of a median process at the posterior margin of the male abdominal tergite VII (exception: G. tuberosa ). The presence of a pair of carinae on the male tergite VII of G. tuberosa suggests that the median process of the male tergite VII in the remaining five species is a derived synapomorphic character state, so that all the species of the G. confusa group should be attributed to the subgenus Sibiota . For illustrations of the previously described species of this group see ASSING (2001a, 2004a, 2005b, 2007).

D i s t r i b u t i o n a n d b i o n o m i c s: Thetypelocalityissituatedinthesouth of Kahramanmaraş province, central southern Anatolia, approximately 40 km to the southwest of Kahramanmaraş. The type specimens were collected by sifting deep litter layers beneath shrubs near a temporary stream at an altitude of 1050-1100 m (MEYBOHM pers. comm.).

Figures

Figs 62-69: Geostiba tuberifera nov.sp.: (62) male habitus; (63) male forebody; (64) male abdomen; (65) male abdominal segments VI-VIII in lateral view view; (66) female tergite VIII; (67) female sternite VIII; (68) median lobe of aedeagus in lateral view; (69) spermatheca. Scale bars: 62: 1.0 mm; 63-67: 0.2 mm; 68-69: 0.1 mm.