Aenictosymbia Maruyama, 2014

Maruyama, Munetoshi, Komatsu, Takashi, Katayama, Yuji, Song, Xiao-Bin & Sakchoowong, Watana, 2014, Myrmecophilous rove beetles (Coleoptera: Staphylinidae) associated with Aenictus hodgsoni (Hymenoptera: Formicidae) from Thailand, with description of two new genera and three new species, Zootaxa 3796 (2), pp. 361-373 : 364-365

Aenictosymbia Maruyama , gen. n.

( Figs. 10–32 )

Type species: Aenictosymbia cornuta Maruyama , sp. n.

Description. Body ( Figs. 10–12 ) myrmecoid, slender, glossy.

Head ( Figs. 10–13 ) almost spherical, with horn on anterior part of frons, gently narrowed posteriad, constricted at base to form “neck”; medial area of head slightly depressed; eyes moderate in size, prominent; antennae ( Figs. 10–13 ) generalized, but segment I strongly thickened.

Mouthparts: Labrum ( Fig. 14 ) generalized, rather irregularly with setae, without pseudopores; hypopharynx ( Fig. 14 ) with mesal area bearing 3 campanifom sensillae, 3 setulae antero-medially, 4 setulae along lateral margin. Mandibles ( Fig. 15 ) almost symmetric, but left mandible slightly thicker, with 2 patches of minute pseudopores around mesal area of dorsal disc, and 2 setae near base of outer margin. Mentum ( Fig. 16 ) sub-trapezoidal, with 2–4 pseudopores, several setae around lateral margin. Labium ( Fig. 17 ): apodeme with lateral lobe short, gently curved, rounded at apex, without medial projection; prementum with 2 real pores and 1 setal pore antero-laterally, strongly sclerotized along anterior margin to connect both bases of palpi; palpus with segment I long, more than 2 time as long as II, with patch of some minute setae near base ( Fig. 17 : arrow; probably sensillae); segment III narrow, elongate; maxilla ( Fig. 18 ) generalized, no or few pseudopores overall; lacinia with 5 spines near apex, densely with pubescence; galea curved near apex.

Pronotum ( Figs. 10–12 , 19, 20 ) elongate, constricted around basal 1/3, shallowly sulcate at midline; prosternite ( Fig. 20 ) subtriangular, elongate, convex at midline; triangular sclerite present ( Fig. 20 : arrow) from middle to near base of cavity.

Mesoventrite ( Fig. 21 ) short, completely fused with metaventrite, weakly carinate between processes of both; metaventrite long, more than 2 times as long as mesoventrite; mesocoxal cavity slightly margined postero-laterally. Elytra ( Fig. 22 ) rounded, well convex above; hind wings developed.

Legs ( Figs. 23–25 ) long, slender; claws developed; fore leg ( Fig. 23 ) with coxa projected at base; base of femur projected ventrad; tarsal segments subequal in length; mid leg ( Fig. 24 ) with coxa small, slightly longer than trochanter; tarsal segments becoming smaller from base to apex; hind leg ( Fig. 25 ) with coxa deeply notched at middle (Fig, 25: arrow); tarsal segments becoming smaller from base to apex.

Abdomen strongly constricted at base (segments II–VI); tergite II rather long, shallowly emarginate on anterior margin; tergite III elongate, dilated apicad; sternite III with posterior area strongly triangularly convex ( Fig. 11 : arrow; no distinct gland openings); tergites IV–VII short, transverse; stermites IV–VII large, strongly convex; tergite VIII with anterior margin rounded, without pseudopores or minute setae; sternite VIII with anterior margin slightly produced, rounded; tergite and sternite IX fused at base of tergite X of which anterior margin submembranous, truncate.

Male: median lobe of aedeagus ( Figs. 29, 30 ) urceolate, strongly produced paramerally at base, with a pair of exposed sclerites of internal sac; paramere ( Fig. 31 ) with basal part of paramerite short, narrow; velum extended near apex of apical lobe.

Female: spermatheca ( Fig. 32 ) coiled at base, with apical part small.

Differential diagnosis. This genus is similar to Aenictophila Seevers, 1965 , in general appearance, the states of meso- and metaventrites, and abdomen, but the convexity of the abdominal sternites is simpler in Aenictosymbia . In Aenictophila , the posterior areas of both sternites III and IV are strongly convex, and their surfaces have distinct gland opening patches, including trichome-like bundles of pubescence on sternite III.

Etymology. A combination of the host genus name Aenictus , and the Greek words syn (meaning "with", "together") and bios (meaning "life", "living"), meaning a symbiont of Aenictus ants. Gender feminine.

Distribution. Central Thailand.

Systematic notes. This genus apparently belongs to the Aenictophila generic group, which is composed of myrmecoid genera of Lomechusini , namely, Aenictophila , Mimaenictus Kistner & Jacobson, 1975 , Procantonnetia Kistner & Jacobson, 1975 , Weissflogia Kistner, 1997. These genera including Aenictosymbia share an exoskeletal modification of a gland on abdominal sternite III (III–V in some genera). This characteristic, including the presence of a gland on sternite III, is not observed in other Lomechusini genera and suggests monophyly of the generic group. Phylogenetics and a detailed morphological study are in progress by MM and his colleagues.

Figures

FIGURES 10–12. Habitus of Aenictosymbia cornuta Maruyama, gen. & sp. n. 10―dorsal view; 11―ventral view; 12―lateral view.

FIGURES 13–23. Body parts of Aenictosymbia cornuta Maruyama, gen. & sp. n. 13―head, dorsal view; 14―labrum (right, epipharynx); 15―left mandible; 16―memtum; 17―labium; 18, right maxilla; 19―pronotum, dorsal view; 20―ditto, ventral view; 21―meso- and meta traces; 22―right elytra; 23―left fore leg.

FIGURES 24–32. Body parts of Aenictosymbia cornuta Maruyama, gen. & sp. n. 24―left mid leg; 25―left hind leg; 26―male tergite VIII; 27―male sternite VIII; 28―male abdominal tergites IX and X; 29―median lobe of aedeagus, lateral view; 30―ditto, apical part, ventra view; 31―paramere; 32―spermatheca.