Chelagyrtodes Szymczakowski, 1973

Seago, Ainsley E. & Leschen, Richard A. B., 2011, Revision and phylogeny of Chelagyrtodes Szymczakowski (Coleoptera: Leiodidae: Camiarinae: Agyrtodini), Zootaxa 3090, pp. 1-20 : 3-4

Chelagyrtodes Szymczakowski, 1973

Diagnosis. Body size small (1.5–2.0 mm), shape ovoid, limuloid to parallel-sided in dorsal aspect. Procoxal cavities internally closed behind by confluence of prosternal process and triangular notal processes arising from hypomeron; procoxal fossa bordered anteriorly by pronounced carina. Series of minute setiferous punctures adjacent to the lateral margins of the pronotal hypomeron. Mesoventral carina pronounced, incomplete anteriorly; mesocoxae not completely divided. Mandibles with subapical spine cluster; maxilla lacking compact, articulated lacinial spore-brush; maxillary palpi with terminal segment narrower than penultimate segment. Males with or without chelate protibiae. Flight wings absent.

Redescription. Body shape limuloid or ovate and parallel-sided in dorsal view; head almost entirely concealed by pronotum. Color dark brown to ferrugineous (highly variable in C. davidi which may be unicolored or bicolored), with tarsi and mouthparts paler brown. Dorsum pubescent to glabrous, pronotum weakly punctate, elytra transversely striate (punctate in C. davidi ).

Antennae not extending beyond hind margin of pronotum in repose; antennal club robust, relatively compact, interrupted with segment 8 subquadrate to transverse, nearly as wide as 7. Eyes round, weakly emarginate posteriorly, coarsely facetted. Epistomal suture present or absent. Mandible short, robust, with pronounced mola, prostheca, and secondary subapical spine cluster ( Fig. 3 , ssc). Maxilla with galea simple, bearing weak setal brush apically; lacinia with apical, non-articulated spine cluster. Maxillary palpi with penultimate segment broader and slightly longer than apical segment; terminal segment apically attenuate, weakly lobed. Labial palpi 2-segmented.

Pronotum transverse, convex anteriorly, hind margin weakly concave, posterior angles acute, weakly produced. Elytra without longitudinal strial impressions; transverse strigae or irregular deep punctures present or absent, but never present in combination. Hind wings absent. Epipleuron complete or very nearly complete, tapering to apex. Procoxal cavities “incompletely closed”, internally closed by prosternal process and externally closed by blunt triangular process of hypomeron; processes not fused. Procoxal cavity narrowly separated from, or nearly contacting, anterior margin of prosternum. Hypomeron with confused row of minute setiferous punctures adjacent to lateral margins and insertion of head. Meso- and metathoracic ventrites transverse; metaventrite less than half as long as mesoventrite along midline. Mesoventrite with median carina. Mesepimeron reduced to small oval sclerite broadly contacting mesocoxal cavities; mesepisternum weakly differentiated, almost completely fused to mesoventrite. Metanepisternum with produced clamp slightly overlapping epipleuron. Legs robust, tibiae spinose. Males with ( Fig. 2 a) or without ( Fig. 2 b) protibiae chelate; protarsi at most weakly expanded with tenent setae, mesotarsi not expanded (with or without tenent setae); tarsal claws simple.

Abdominal ventrites strongly transverse, male abdominal ventrite 6 weakly notched to completely divided at apex.

Male genital segment elongate to subquadrate, with or without produced anterior apophysis. Aedeagus with paired symmetrical parameres, variously straight, flattened, or bent. Median lobe simple, gently curved ventrad, with or without papilliform apex.

Female genitalia consisting of an internal unsclerotized, sac-like bursa flanked by elongate, flared paraprocts and short external gonocoxites and styli.

Remarks. Both sexes of Chelagyrtodes can be distinguished from other agyrtodine leiodids ( sensu Newton 1998 ) by their small size and the combination of diagnostic characters mentioned above. The chief diagnostic character for Chelagyrtodes as defined by Szymczakowski was the chelate (expanded and strongly bent) protibiae in males ( Fig. 2 a); this characteristic is sufficient to recognize two of the five species in the genus. The remaining species lack the male protibial modification, but are otherwise morphologically similar to C. crowsoni , sharing the loss of lacinial spore-brush and the presence of a subapical mandibular spine cluster.

Placement of Chelagyrtodes within Agyrtodini is supported by analyses of morphological and molecular data (Seago, in prep.). The elytra with transverse strigae in all species apart from C. davidi , and lacking longitudinal strial impressions or puncture rows, suggest placement in the Agyrtodes group delineated by Newton (1985).

Newton (1998) reports “13 new species seen” for this genus, but based on careful examination of external and internal characters in all available material, we recognize five species in the genus.

Etymology. Chelagyrtodes is derived from Agyrtodes , with a prefix referring to the chelate protibiae of males (Greek chele, meaning “claw”). The genus name is masculine, following the gender of the suffix - odes.

Figures

FIGURES 2 – 3. Details of Chelagyrtodes. 2) Tibial dimorphism of adult male: a) chelate protibia (C. crowsoni); b) simple protibia (generalized). 3) Generalized mandible with subapical spine cluster (SSC).