Olibrus socotranus, Gimmel, 2012

Gimmel, Matthew L., 2012, Phalacridae of Socotra Island (Coleoptera: Cucujoidea), Acta Entomologica Musei Nationalis Pragae 52, pp. 233-240 : 236-238

Olibrus socotranus sp. nov.

( Figs. 6–10 )

Type locality. Yemen, Socotra, Noged, Mokhar, 12°18′43″N 53°43′31″E.

Type material. HOLOTYPE: J ( NMPC), point mounted, genitalia removed and placed in DMHF on acetate card with specimen, abdomen removed and remounted on point, with label data ‘ Yemen, Socotra Isl., / Noged, Mokhar, / 31.iii.2001, / leg. V. Bejček & K. Šťastný // HOLOTYPE J / Olibrus / socotranus Gimmel / des. M.L. Gimmel

2012 [red label]’. PARATYPES (N =17): Same capture data as holotype, with label ‘ PARATYPE / Olibrus / socotranus Gimmel / det. M.L. Gimmel 2012 [yellow label]’ (5 CULS; 9, NMPC; 3, MLGC).

Description. Total length 1.8–2.2 mm. Color uniformly black or nearly black dorsally, with faint greenish metallic tinge ( Fig. 6 ); ventrally dark rufotestaceous, appendages bright rufotestaceous.

Head extremely finely, moderately densely punctate; frontoclypeus with distinct emargination above antennal insertion; eye medium-sized, extremely shallowly emarginate at level of frontoclypeal shelf, eyes separated by about two eye widths in frontal view; lacking periocular groove. Maxillary palp with palpomere IV short, wide, fusiform; labial palp very small, inconspicuous. Antenna ( Fig. 10 ) short, not reaching posterior corner of pronotum; antennomeres VII and VIII distinctly longer than wide, IX slightly longer than X, XI weakly turbinate, shorter than IX and X combined. Pronotum with hind angle distinctly obtuse; scutellar lobe weakly developed. Pronotal lateral bead fine, complete, not distinctly thickened at front angle; pronotum with very weak but evident border along posterior margin; punctation finer and sparser than that of head; pronotum completely lacking microsculpture. Elytron with two striae near suture, medial stria extending about two-thirds length of elytron, lateral stria extending about one-half length of elytron, striae joining near apex; elytral surface smooth, with faint trace of additional longitudinal striae represented by rows of exceedingly weak elongate punctures, with round interstrial punctures also faintly indicated; transverse strigae and microsculpture completely absent from elytron. Prosternum entirely glabrous; prosternal process apex with margin completely absent; protibia with two spines at outer apical angle. Metaventral process broader than mesocoxal cavity, extending distinctly anterior of mesocoxae, evenly rounded at apex, forming a shelf over mesoventrite; metaventral postcoxal line closely adhered to mesocoxal cavity; metaventrite very weakly, sparsely punctate, punctures entirely absent from large areas posteromedially; metatarsus shorter than metatibia, male with four tarsomeres, female with five; ventral (longest) metatibial spur nearly equal to metatarsomere I ( Fig. 9 ); metatarsomere I less than half length of II; metatarsomere II subequal to III–IV(–V in female) combined.

Aedeagus with tegmen ( Fig. 7 ) short, broad, fused parameres broader than long, slightly emarginate at apex, without setae; penis ( Fig. 8 ) blunt to slightly emarginate at apex, acutely pointed at base, internal sac with ‘ω’-shaped sclerite, ejaculatory duct with spirally arranged sclerotization proximal to penis.

Differential diagnosis. Distinguished from other Socotran phalacrids by the two elytral sutural striae, short metatarsi ( Fig. 9 ), and deep black coloration ( Fig. 6 ). It differs from other species of Olibrus by the combination of deep black coloration, two sutural striae that coalesce apically and do not approach the base of the elytra, the almost total lack of striae on the elytral disc, lack of microsculpture on the dorsal surface, the unbordered pronotal base, the bright rufotestaceous appendages (with antennal club not infuscated), the highly obtuse pronotal hind angles, and details of the aedeagus, especially the short, wide parameres ( Fig. 7 ) and the acutely pointed base of the penis ( Fig. 8 ).

Distribution. So far known only from Socotra, from one locality in the Noged Plain.

Etymology. The specific epithet refers to the island of Socotra, from which all known specimens of this species originate.

Notes. This species keys to Olibrus platysternus Champion, 1925 in LYUBARSKY’ s (1998) treatment of some southern African members of this genus. However, O. socotranus sp. nov. is slightly larger on average, has a more slender antennal club, and differs in aedeagal morphology based on the illustration in LYUBARSKY (1998). It is also similar to O. quadristriatus Champion, 1925 but differs from that species in lacking a medio-basal border on the pronotum, antennal club not darkened, and differences in aedeagal morphology (that species also illustrated in LYUBARSKY 1998).

I have seen a small collection of northeastern African Olibrus and none were similar to this new species.Additionally, investigation of primary literature for previously described but still poorly known African, Eastern Mediterranean, and Middle Eastern species of Olibrus revealed specific differences in all cases. However, without examination of a large number of types scattered among numerous museums, the possibility exists that this species has been previously described from another locality.

Figures

Figs. 6-10. Olibrus socotranus sp. nov. 6 – dorsal habitus; 7 – tegmen, ventral; 8 – penis, ventral; 9 – metatibia and tarsus, ventral; 10 – antenna. Scale bars = 0.3 mm.