Acrotrichis segmenta, 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 : 201

Acrotrichis segmenta sp. n.

( Figs. 9A –N)

Habitus Figs. 9A ,B. Length 1.22 mm. Colour dark brown. antennae and legs yellow. Antennomeres 3–11 0.48– 0.49 mm long Fig. 9 C. Mentum and submentum chaetotaxy Fig. 9 G. Width across eyes 0.44 mm. Pronotum 0.81– 0.85 mm wide, 0.44–0.46 mm long, sides without an insinuation before the hind angle when viewed at 45° Fig. 9 D. Elytra 0.68–0.69mm long, 0.68–0.78 mm wide, with microtrichiae on cells, Fig. 9 I, and a short, projecting epimeron at the humerus, Fig. 9 H. Mesoventrum with collar sloping steeply down at the humeri, Fig. 9 J. Posterior margin of metaventrum and metacoxal plates Fig. 9 K. Pygidium with a row of setae on the anterior margin, Fig. 9 L. Ventrites 5,6 each with a pair of longer setae, Fig. 9 N.

Male: no males were detected amongst the 148 specimens studied and the species is presumed to be parthenogenetic.

Female: spermatheca subject to variation according to maturity particularly in the form of the pump. Examples chosen to represent the extremes are shown in Figs. 9 E, 9Fa, 9Fb.

Etymology. From the Latin segmentatus meaning adorned with borders or patches and referring to the microtrichia on the elytral cells.

Diagnosis. The microtrichiate elytra will separate this species from all others except armillata which is much smaller. (Note: I have seen other species with similar elytra in several S. American countries). In both of the two large collections of segmenta studied (32 and 91 specimens) a full range of teneral to mature examples were present ranging in colouration from almost translucent to dark brown. Because teneral specimens are softer and less rigid they tend to flatten when mounted becoming wider than the more rigid, mature specimens. These widths are reflected in the measurements cited above which were made from specimens chosen to represent the full range of sizes.

Type data: Holotype: ♀, GPS30, BOL / Nov 2013/7, Bolivia 2013, Santa Cruz dep., W. Amboro NP, Siberia Pass env., 2508m, 28.xi, S. 17°50'27" E.64°41'59", sifting litter, Winkler app. extr., P.Baňař lgt. ( UASC). Paratypes ♀, same data as Holotype ( UASC / MMBC); 97 ♀, 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. ( UASC / MMBC, BMNH); 6♀, GPS38, BOL / Nov. 2013/13, Bolivia 2013, Santa Cruz dep., W. Amboro NP, Barientos, 1883m, 29.xi, S. 18°06'11" E.63°48'09", sifting litter palms, Winkler app. extr., P.Baňař lgt. ( UASC / MMBC); 11 ♀, 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); 32 ♀, GPS32, BOL / Nov 2013/09, Bolivia 2013, Santa Cruz dep., W. Amboro NP, Siberia Pass env., 2450m, 28.xi, S. 17°50'12" E.64°42'08", sifting litter, Winkler app. extr., P.Baňař lgt. ( BMNH).

Figures

FIGURE 9. A. segmenta. A, habitus, large immature specimen; B, habitus, small mature specimen; C, antennomeres 3 – 11; D, side of pronotum viewed at 45 °; E, spermatheca, immature specimen; Fa & b, spermatheca mature specimen; G, mentum and submentum showing chaetotaxy x 820; H. elytron; I, elytral cells showing microtrichiae x 2960; J, metaventral posterior margin and coxal plates x 465; K, mesoventrum x 410; L, pygidium; M. sternite.