Microtrichis pectana, Darby, Michael, 2015

Darby, Michael, 2015, Studies of Bolivian Ptiliidae (Coleoptera) 2: The subfamily Acrotrichinae including two new genera Petrotrichis and Microtrichis, and eight new species of Acrotrichis, Zootaxa 3999 (2), pp. 190-210 : 206-210

Microtrichis pectana sp. n.

( Figs. 12 A–L)

Habitus Fig 12 A. Length 0.62 mm. Colour dark brown, antennae pale yellow, legs slightly darker yellow. Antennomeres 3–11 0.24 mm long Fig. 12 C, 10–11 with sensillae Fig. 12 L. Mentum and submentum Fig. 12 H. Width across eyes 0.23 mm. Pronotum 0.53 mm wide, 0.30 mm long, the hind angles with only a very indistinct angle when viewed at 45° and with a protruding seta, Figs. 12 B, 12D. Elytra 0.36 mm long, 0.33 mm wide. Underside showing meso- and metaventra 12I. Hind coxae showing fringe of setae Fig. 12 J.

Male: aedeagus Fig. 12 F; ventrite 7 Fig. 12 G; ventrites 6 and 7 Fig. 12 K.

Female: spermatheca Fig. 12 E.

Etymology. From the Latin pectanus meaning comb-like and referring to the setae on the hind coxae.

Type data: Holotype: ♂, GPS35, BOL / Nov 2013/10, Bolivia 2013, Santa Cruz dep., W. Amboro NP, Barientos, 1806m, 29.xi.2013, S. 18°05'55" E.63°48'04", sifting rotten wood, Winkler app. extr., P.Baňař lgt. ( UASC); Paratypes: 7 exs, same data as holotype; 4♀, GPS38, BOL / Nov 2013/13, Bolivia 2013, Santa Cruz dep., W. Amboro NP, Barientos, 1883m, 29.xi.2013, S. 18°06'11" E.63°48'09", sifting litter, palms, Winkler app. extr., P.Baňař lgt. ( UASC / MMBC); 5♂ 4♀, GPS36, BOL / Nov 2013/11, Bolivia 2013, Santa Cruz dep., Barientos, 1817m, 29.xi.2013, S. 18°06'00" E.63°48'05", sifting litter, Winkler app. extr., P.Baňař lgt. ( BMNH); 34 exs, GPS37, BOL / Nov 2013/12, Bolivia 2013, Santa Cruz dep., Barientos, 1813m, 29.xi, S. 18°06'06" E.63°48'08", sifting litter, Winkler app. extr., P.Baňař lgt. ( UASC / MMBC, BMNH); 1♂, ♀, GPS31, BOL / Nov 2013/08, Bolivia 2013, Santa Cruz dep., W. Amboro NP, Siberia Pass env., 2481m, 28.xi, S. 17°50'25" E.64°41'58", sifting litter, Winkler app. extr., P.Baňař lgt. ( BMNH).

Separation from related species. The Nephanini currently includes seven genera which differ from those in Acrotrichini by not possessing backwardly projecting pronotal hind angles. Excluding those genera which exhibit clear morphological differences, three only are likely to be confused with Microtrichis - Baeocrara Thomson, Nephanes Thomson and Smicrus Matthews. Of these Baeocrara and Nephanes do not include any species described from S. America, but Smicrus is abundant in Chile with nine recognised species ( Darby and Johnson 2011) and I have also seen specimens from Argentina.

From Baeocrara Microtrichis may be distinguished by the much less strongly punctulated dorsal surface and the shape of the mesoventral keel the hind border of which is interrupted medially in Baeocrara ( Fig. 11 D).

From Nephanes Microtrichis differs in the following respects: larger and less parallel sided body form; pronotal setae arising from close to the posterior margin of the cells ( Nephanes : from the middle of the cells); elytral setae arising from clearly denoted concave depressions in the middle of the cells ( Nephanes : cells of a different shape without concave depressions, setae arising from under the posterior margin ( Figs. 11 A–C); mentum long, straight sided, narrowest at base ( Nephanes : short, sides rounded); hind angles of pronotum rounded ( Nephanes angulate); mesoventral collar sloping posteriorly at humeral angles, widest medially and with a small medial incision ( Nephanes : almost parallel sided throughout, barely sloping at shoulders and with a humeral tooth); male metacoxae with a 'comb' of flattened setae ( Nephanes : without a comb); spermatozoa small, presumed flagellate ( Nephanes : large, amoeboid); spermathecae with a very narrow parallel sided duct ( Nephanes : with a broad duct).

From Smicrus Microtrichis is clearly separated by its smaller size and more rounded and narrower body form. Additionally, the less strongly sculpted dorsal surface ( Figs.11 A,B,E); the more truncate elytra; and the almost square aedeagus ( Smicrus : more elongate and narrowed anteriorly) also distinguish Microtrichis .

Figures

FIGURE 11. Exoskeletal details. A, Microtrichis pectana pronotum x 3150. B, M. pectana elytra x 3050. C, Nephanes titan pronotum and elytra x 2320. D, Baeocrara variolosa mesoventral collar x 1020. E, Smicrus aubaei pronotal and elytral sculpture x 1780.

FIGURE 12. Microtrichis pectana. A, habitus; B, side of pronotum viewed at 45 °; C, antennomeres 3 – 11; D, hind angle of pronotum showing seta x 1700; E, spermatheca; F, aedeagus; G, male ventrite H. mentum and submentum x 1320; I, underside showing meso and metaventra x 445; J, metacoxae showing fringe x 1800; K, male ventrites six and seven x 2280; L, antennomeres 10, 11 x 1700.