Lomechusoides Tottenham, 1939

Jászay, Tomáš & Hlaváč, Peter, 2013, A taxonomic revision of the myrmecophilous genus Lomechusoides Tottenham, 1939 (Coleoptera: Staphylinidae: Aleocharinae) Part I. Redescription of the genus, definition of species groups and the revision of the amurensis Wasmann 1897 species group, Zootaxa 3683 (1), pp. 65-81 : 66-67

Genus Lomechusoides Tottenham, 1939

Lomechusoides Tottenham, 1939: 226 . Type species: Staphylinus strumosus Fabricius, 1793 , original designation

Goniodes Stephens, 1829: 260 . Type species: Staphylinus strumosus Fabricius, 1793 , virtual monotypy (attributed to Kirby; preoccupied, not Nitzsch, 1818)

Lomechusa Gravenhorst : Erichson, 1839 (redescription); Ganglbauer, 1895 (redescription); Wasmann, 1897 (revision, key); Wasmann, 1888 (biology); Feynes, 1920: 304 (redescription, catalogue, distribution); Bernhauer, 1936 (key to known species)

Lomechusoides Tottenham : Maruyama & Hlaváč, 2004 (catalogue, new combinations, synonyms)

Diagnosis. The genus Lomechusoides can be readily separated from between three genera of the subtribe Lomechusina by the combination of following characters: 1) antennae and legs stout, 2) pronotum with lateral part dull, finely microsculptured and 3) lacinia without hook or spine.

Redescription. Body yellowish-brown ( Fig. 48 ), pronotum partly darker, elytra and tergites lighter, some tergites with basal part darker.

Head: ( Fig. 1 ) quadrate, longer than wide, or as long as wide, eyes weakly protuberant, shorter than temples, temples slightly convergent posteriorly or parallel, surface with sparse puncturation and setation, with microsculpture, matt with frontal triangular depression between well developed antennal protuberances. Labrum bilobed, wider than long, with some setae. Mandibles ( Fig. 2 ) symmetric, angularly bent, lacking internal teeth, basal dorsal part in middle with numerous dentiform protuberances, lateral edge with dense setation. Maxillae ( Fig.3 ) with galea longer than lacinia, both of about same width, galea evenly expanded in basal part, in apical part narrowed, palpifer and stipes with setae, maxillary palpi 4-segmented, palpomere I small, subquadrate, II expanded apically, widest, III slightly shorter and slender, IV as long as I, needle-like. Labium ( Fig. 4 ) with prementum slighty longer than wide in basal part, anterior part with numerous setae, basal part with numerous pseudopores, glossy, indistinctly divided in two rounded lobes, lacking sensillae, labial palpi with palpomere I barrel-like, 1.5 as long as wide, about three times as long as II, palpomere II shortest, trapezoidal, wider than long, palpomere III narrowest, subparallel, three times as long as wide, as long as II, palpomere I and II with setae, III with some pseudopores. Mentum ( Fig. 5 ) rhomboidal, 1.3 times as wide as long, widest at base, narrowed anteriorly, anterior margin deeply excavated, in lateral anterior and posterior corners with about seven pseudopores, in middle with about four pseudopores. Gular suture widely separated, closest in middle, suddenly narrowed anteriorly and evenly narrowed posteriorly. Antennae ( Fig. 6 ) long, when bent backwards usually reaching or exceeding base of elytra, all antennomeres more or less asymmetric, scape large, larger than all other antenommeres individually, pedicel smallest, II–III rhomboid, both slightly pedunculate, IV–X barrel-like shaped, terminal antennomere pointed apically, longest, all antennomeres matt, with setation, antennomeres III–IV in males with bunch of lateral setae (absent in L. suensoni ). Pronotum ( Figs. 7, 8 ) variable in shape and size, transverse, widest at base, anterior angles rounded, posterior angles well-defined, sharp, surface sometimes with tubercles, basal margin with strong median lobe, surface with various depressions, pronotal disc with uneven puncturation, with or without microsculpture, hypomeron large and matt. Mesoventrite wide, five times as wide as mid-line length, with short and fine setae, surface with microsculpture, posterior mesoventral process truncated. Metaventrite ( Fig. 9 ) about four times as long as mesoventrite, surface unevenly punctured, setaceous, with or without microsculpture, macrosetation species-characteristic, shape of metaventral process species-characteristic, with or without depression.

Elytra as long as or shorter than pronotum, elytron about as long as wide or slightly shorter, finely punctured with setation, in basal and humeral part with macrosetae, posterior margin of elytra in front of posterior corner excavated, angle of sutura rounded, wings well-developed.

Abdomen robust, evenly expanded, tergite V widest, from tergite V slightly convergent posteriorly, abdomen longer than head, pronotum and elytra combined. Paratergites III–V with trichomes, lateral margins of tergites II– IV, VIII–X as well as lateral margins of sternites II–IV and metepimeron with dense golden setae, tergites V–VII in posterior corners with short setae, surface with or without weak microsculpture, sternites evenly punctured with erect macrosetae.

Legs long, with setation, apical part of femora with bunch of long setae ( Fig. 10 ) (groups L. amurensis and L. strumosus ) or lacking any long setae (groups L. minor and L. straneoi ), tarsal formula 4-5-5, trochanters similarly shaped, semi-triangular, procoxae about three times as long as wide, mesocoxae 1.3 times as long as wide and metacoxae about as long as wide, tibiae slightly shorter than femora, slightly convergent posteriorly, coxae, trochanters and ventral part of femora with few macrosetae.

Sexual dimorphism. setae on antenommeres III–IV longer in males ( Fig. 6 ), tergites and sternites VIII differently shaped in males and females ( Figs. 11 a, 11b, 12a, 12b).

Distribution. Almost the whole Palaearctic region, from Spain to Siberia and Russian Far East, China and Japan.

Biology. Lomechusoides is a strictly myrmecophilous genus with symphilic way of life which so far has been recorded only with ants of the genus Formica Linnaeus, 1758 and Myrmica Latreille, 1804 . The following ants have been found as hosts of Lomechusoides so far: Formica cunicularia Latreille, 1798 ; F. f u s c a Linnaeus, 1758, F. pratensis Retzius, 1783 ; F. r u f a Linnaeus, 1761; F. rufibarbis Fabricius, 1793 ; F. sanguinea Latreille, 1798 ; Myrmica rubra Linnaeus, 1758 and M. scabrinodis Nylander, 1846 .

Figures

FIGURES 48 – 50. 48, L. strumosus from Bardejov, Slovakia, habitus; 49, L. amurensis, from Irkutsk, habitus; 50, L. schneideri, HOLOTYPE, habitus

FIGURES 1 – 6. L. strumosus 3, 1, head, dorsal view (L: 1 mm, W: 0.90 mm) (scale: 0.5 mm); 2, right mandible, dorsal view (scale: 0.1 mm); 3, right maxilla, ventral view (scale: 0.1 mm); 4, labium, ventral view (scale: 0.1 mm); 5, mentum, ventral view (scale: 0.1 mm); 6, 3 antenna (scale: 0.5 mm);

FIGURES 7 – 13. L. strumosus, 7, 3 pronotum, dorsal view (L: 1.20 mm, W: 1.95 mm) (scale: 0.5 mm); 8, 3 pronotum, ventral view (L: 1.20 mm, W: 1.95 mm) (scale: 0.5 mm); 9, 3 metaventrite ventral view (L: 1.30 mm, W: 1.75 mm) (scale: 0.5 mm); 10, 3 chaetotaxy – mesothoracic leg, apical part of femur; 11 a, 3 tergite VIII (scale: 0.5 mm); 11 b, 3 sternite VIII (scale: 0.5 mm); 12 a, Ƥ tergite VIII (scale: 0.5 mm); 12 b, Ƥ sternite VIII (scale: 0.5 mm); 13, posterior margin of right elytra, chaetotaxy