Socotrasilis enigmatica, Geiser, 2017

Geiser, Michael, 2017, First record of the family Cantharidae on Socotra, with description of a new genus and two new species of the subfamily Silinae (Coleoptera: Elateroidea), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57, pp. 93-99 : 98-99

Socotrasilis enigmatica sp. nov.

( Figs 5–8 )

Type locality. Yemen, Socotra, near Hadiboh.

Type material. HOLOTYPE: J, ‘ Yemen, Soqotra Is. / 21.xi.-12.xii.2003 / HADIBOH env., ca 10-100m / 12°65′02′′N, 54°02′04′′E / [GPS], David Král lgt. // YEMEN – SOQOTRA 2003 / Expedition; Jan Farkač, / Petr Kabátek & David Král //? Silidius / sp. / V. Švihla det., 2012’ ( NMPC) . PARATYPE: 1 J, ‘Socotra I., 17.-18.ix.2000 / Lahas / V. Bejček, K. Šťastný lgt.’ ( NMPC).

Description. Male ( Fig. 5 ): Pale yellow to orange testaceous, with pitchy black elytra and antennomeres III–XI; tarsi more or less infuscate; scutellum yellow.

Head large and strongly transverse, sparsely covered in very fine, greyish recumbent pubescence, arising from very fine punctures; with large, laterally protruding eyes. Frons between antennal insertions only about half as wide as space between eyes. Antennomeres III–X serrate in males. Scape short and thick, not much longer than wide; antennomere II very small, less than half size of scape; III about as long as I and II together; IV–X slightly longer than III; XI longest and thinnest.

Pronotum as in Fig. 8 , shining and with sparse, inconspicuous pubescence, its lateral margin in anterior half with bulge, followed by sharp emargination after middle; underneath emargination with ear-like lobe; emargination and ear-like lobe together form opening to short, deep groove, continued underneath antero-lateral bulge and open towards side.

Scutellum flat, longer than wide, with broadly rounded apex, with pubescence similar to elytra.

Elytra rather matt, with moderately dense, long greyish pubescence, arising from very fine punctures; without any traces of costae; leaving small gap between individually rounded apices and not entirely covering apical two tergites.

Abdomen weakly sclerotised and with fine, yellowish recumbent pubescence.

Apical tergite subtriangular, rather pointed, without emargination or other modifications. Apical ventrite split into two lobes, each about as long as wide.

Aedeagus as in Fig. 6 . Ventral basal piece (‘Ventrales Basalstück’ according to WITTMER 1969) produced into two rounded lobes, median lobe posteriorly very broad, rather flat, weakly sclerotised and covering two small, stick-like laterophyses behind, which are only visible when median lobe is lifted up; dorsal shield (‘Dorsalschild’) short, broad, with bulging margins in fronto-ventral view, dorsally rather flat, subcircular, without any trace of apical emargination ( Fig. 7 ).

Female. Unknown.

Measurements. Total body length: 6.2–6.8 mm; length or elytra: 4.3–4.4 mm; width of elytra: 2.0– 2.1 mm; length of pronotum: 1.1–1.2 mm; width of pronotum 1.6 mm; width of head: 1.6 mm.

Etymology. Named by Latin adjective ‘ enigmatica ’ in reference to its ‘enigmatic’ phylogenetic position.

Distribution. Only known from the lowland parts of Socotra Island.

Figures

Figs 5–8. Socotrasilis enigmatica gen. et sp. nov. 5 – holotype, dorsal habitus; 6 – male genitalia, ventral view; 7 – male genitalia, dorsal view; 8 – pronotum of male. Scale bars represent 1mm.