Ecitonides volans, Assing, 2012

Assing, V., 2012, A new species of the myrmecophilous genus Ecitonides from Peru (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 44 (1), pp. 401-408 : 402-407

Ecitonides volans nov.sp. ( Figs 1-8 , Map 1 )

T y p e m a t e r i a l: Holotype: " Peru, Huanuco Prov., Panguana station at Rio Llullapichis , 9°37'S, 74°56'W, 260 m, at light, 2.-20.X.2009, leg. G. Riedel / Holotypus Ecitonides volans sp.n. det. V. Assing 2012".

E t y m o l o g y: The specific epithet (Latin, present participle of volare: to fly) alludes to the fact that the holotype was collected on the wing.

D e s c r i p t i o n: Body length 5.9 mm. Habitus as in Fig. 1 . Coloration: forebody pale-greyish; abdomen pale-reddish with segments VI-VIII slightly darker reddish; abdominal segments IX-X with conspicuous tuft of long black setae; legs and antennae pale-reddish.

Head ( Figs 1, 3 ) strongly oblong, twice as long as wide, widest across eyes; lateral margins behind eyes straight and converging posteriad; postocular portion more than three times as long as eyes; whole head densely covered with large, unflattened "tubercles" arranged in rather regular longitudinal rows. Eyes well-developed, somewhat kidneyshaped in lateral view ( Fig. 3 ), and distinctly visible from above ( Fig. 1 ). Antenna ( Fig. 4 ) 1.7 mm long, much longer than head; antennomere I approximately as long as the combined length of II-IV; II and III distinctly oblong and of subequal length; IV and V oblong, but less so than II and III; VI and VII weakly oblong; VIII and IX approximately as long as broad; X weakly transverse; XI approximately as long as X and transverse.

Pronotum approximately 1.4 times as long as broad and slightly broader than head, widest approximately in the middle, more strongly tapering anteriad than posteriad; whole dorsal surface convered with large and unflattened "tubercles" arranged in distinct rows, the "tubercles" of the series along midline larger than the lateral "tubercles".

Elytra of trapezoid shape, approximately 0.8 times as long as pronotum, lateral margins distinctly diverging posteriad; suture gaping posteriorly; each elytron with five series of "tubercles" visible from above. Hind wings fully developed. Legs stout; metatibia flattened; all legs furnished with greyish scales; external ridges of tibiae furnished with seams of scales; tarsi short; tarsomeres I-IV transverse; tarsomere V approximately as long as the combined length of I-IV.

Abdomen ( Fig. 6 ) wedge-shaped, distinctly tapering posteriad, widest at segment IV; segments III-VI with pronounced and sharply edged paratergites; segment VII with narrower and more obtuse paratergites; tergites III-V with numerous "tubercles" of variable size and with transverse row of larger "tubercles" at posterior margins; tergite VI covered with scales, its posterior margin with a transverse row of "tubercles"; tergite VII with longitudinally striate sculpture and with scales, its posterior margin with narrow palisade fringe; tergite VIII longitudinally striate and densely furnished with golden, depressed, and relatively long setae, its posterior margin semi-transparent and weakly concave; segments IX-X strongly modified and with tufts of conspicuously long black setae.

: sternite VIII longitudinally striate and with dense and depressed pubescence, poste- rior excision rather broad and not very deep ( Fig. 5 ); aedeagus 0.7 mm long and shaped as in Figs 7-8 ; parameres absent; internal sac with pair of long and distinctly sclerotised apical structures and with large, dark, membranous dorsal structure.

C o m p a r a t i v e n o t e s: The new species is distinguished from all its congeners by the shorter and posteriorly more strongly dilated elytra, the denser "tubercles" on the forebody, and additionally as follows:

from E. spectabilis by much smaller size ( E. spectabilis : body length 10 mm), paler coloration ( E. spectabilis : blackish-brown), the more slender pronotum, and by the unflattened "tubercles" of the forebody; for an illustration of the habitus of E. spectabilis see BORGMEIER (1932);

from E. fraterculus by the different head shape ( E. fraterculus : with parallel lateral margins), slightly larger size ( E. fraterculus : body length 5 mm), relatively longer antennae with more slender antennomeres III-X ( E. fraterculus : antennae approximately as long as head, antennomeres VII-X strongly transverse), and by the dense "tubercles" on the abdominal tergites III-V ( E. fraterculus : small "tubercles" present only at the base of tergite III);

from E. tuberculosus by the paler abdomen, the relatively shorter antennae, and the much denser "tubercles" on the abdominal tergites III-V; for illustrations of the habitus and the antenna of E. tuberculosus see BRUCH (1933), the head is figured by WASMANN (1909) (as E. fiebrigi );

from E. verrucosus by the different coloration ( E. verrucosus : body ferrugineous with darker abdomen), the more slender head and abdomen, and by the presence of "tubercles" on the abdomen ( E. verrucosus : abdomen with longitudinal carinae, but without "tubercles"); for a drawing and a photograph of the habitus, as well as illustrations of other external characters and the mouthparts see BRUCH (1933);

from E. brevicornis by relatively longer antennae, the different position of the eyes ( E. brevicornis : less visible when viewed from above), and a more slender pronotum; for a photograph of the habitus of E. brevicornis see BORGMEIER (1949);

from E. longiceps by smaller size ( E. longiceps : 7 mm), the differently shaped head (parallel-sided in E. longiceps ), the relatively longer antennomere III (shorter than II in E. longiceps ), the larger and differently situated eyes ( E. longiceps : eyes almost obsolete, barely visible when viewed from above); for illustrations of the habitus and the head see WASMANN (1900) and WASMANN (1909), respectively.

C o m m e n t: The phylogenetic affiliations of the genus within the tribe Paederini is somewhat unclear, particularly because the external characters are so conspicuously derived as a result of adaptation to an association with army ants. According to NEWTON (pers. comm.), Ecitonides may be close to the Echiaster ERICHSON 1839 , which is currently in the subtribe Echiasterina . However, based on the morphology of the mouthparts, the antennae, and the male sexual characters, it does not seem unlikely that the genus may actually belong to the Cryptobiina.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: Thetypelocalityissituatedin Huanuco province, central Peru, near the junction of the Llullapichis and Pachitea rivers at an altitude of 260 m. Thus, the known distribution of the genus is considerably expanded towards the west ( Map 1 ). The holotype was collected with a light trap in October. As can be inferred from what is known about other species of the genus, E. volans is probably associated with army ants.

Figures

Map 1: Distribution of Ecitonides species. Open squares: E. brevicornis; filled square: E. volans; open and filled triangles: E. tuberculosus; filled triangle: E. verrucosus; open diamond: E. longiceps; filled diamond: E. spectabilis; filled circle: E. fraterculus. The data for all the species, except E. volans, are taken from SEEVERS (1965).

Figs 1-5: Ecitonides volans nov.sp.: (1) habitus; (2) forebody in lateral view; (3) head in lateral view; (4) antenna; (5) male sternite VIII. Scale bars: 1-2: 1.0 mm; 3-5: 0.5 mm.

Figs 6-8: Ecitonides volans nov.sp.: (6) abdomen; (7) aedeagus in lateral view; (8) aedeagus in ventral view. Scale bars: 6: 1.0 mm; 7-8: 0.5 mm.