Aptilotella gemmula Luk & Marshall, 2014

Luk, Stephen P. L. & Marshall, Stephen A., 2014, A revision of the New World genus Aptilotella Duda (Sphaeroceridae: Limosininae), Zootaxa 3761 (1), pp. 1-156 : 39-40

Aptilotella gemmula Luk & Marshall , sp. n.

Figures 46–48 , and 276–287

Description. Habitus as in Figures 46 and 47 . Body length 0.8–1.0 mm. Head ground color yellow-orange. Frons finely rugose; brown medial stripes each about two-fifths the width of frons, broadening posteriorly, diffuse along the anterior margin; orbital stripes brown, narrow. Ocellar tubercle scarcely raised; ocellar bristle two-thirds the length of frons. Orbital bristle absent; orbital setulae minute, in four pairs. Interfrontal setae in two pairs. Face shining; facial tubercle narrow; excavation and clypeus brown; gena dull, with brown ventral margin. Antenna brown, first flagellomere darker. Scutum and scutellum black, shining. Scutum uniformly setose; short, twice wider than long. Scutellum uniformly microtrichose; flat, 3.5 times wider than long, 0.6 times the width of scutum. Apical scutellar bristles 1.7 times as long as basal. Pleuron black, upper half of anepisternum with reflective pruinose stripe visible from an oblique angle. Legs brown; fore and mid tibiae dark brown, hind tibia faintly banded; mid tibia with two anterodorsal and one distal posterodorsal bristle. Wing rudiment grayish. Abdomen black with bluish iridescence; tergites uniformly setose and microtrichose; sternites finely microtrichose. Epandrium dark reddish brown; cercus and surstylus dull yellow.

Male terminalia. Sternite 5 ( Figs. 48 , 279 ) lunate; posteromedial fifth emarginate, the outer margins lobed inward and bearing 3–4 setae; emargination medially giving rise to a triangular process, basally to a pair of densely setaceous stubs, with a membranous lining fringed with several rows of spinules and medially bearing a pair of long medial setae. Synsternite 6+7 as in Figure 278 . Cercus ( Figs. 276, 277 ) stout and densely clothed in setulae; basal margin with one long seta medially and several setae in distal half; apex claw-like, with a preapical sensory seta. Surstylus ( Figs. 276, 277 ) cylindroid; distally flattened and broad, anteriorly sharply pointed and medially with a blunt marginal tooth; ventral face with scattered setae. Postgonite ( Fig. 282 ) curved; descending arm straight, slightly tapering, with two anterior marginal sensory setae; articulatory process for pregonite undeveloped, triangular; articulatory process for basiphallus stalked, apically dilated. Hypandrium ( Fig. 283 ) very broad; medial rod apically spatulate; posteromedial fork very wide; hypandrial arms apparently fused to medial rod and swept back from its spatulate apex and tapering to a point; pregonite minute and squared. Aedeagus as in Figures 280 and 281 . Basiphallus short, cylindrical; articulatory process for postgonite pointed, short. Ventrobasal sclerite present. Lateral flanking sclerite partitioned in two; the basal half darker, square and fused ventrobasally by a narrow bridge; the smaller distal half pale, irregularly subquadrate, its dorsal margins divergent and with a medial tooth. Ventral flanking sclerites supporting a sail-like membrane; the slender basal article descending and with threadlike attachment to ventral corner of lateral flanking sclerite; the short medial article arising midway along the basal article; the distal article similar to basal article but ascending. Internal sclerite club-shaped, articulated with apicoventral margin of lateral flanking sclerite. Curved dorsal sclerite club-shaped, originating from inside distal ventral margin of lateral flanking sclerite; apex rough and knobby.

Female terminalia. Epiproct ( Fig. 284 ) subpentagonal, with a pair of marginal teeth. Each half of tergite 8 ( Figs. 284–286 ) triangular, rather small and weakly convex. Cercus three times as long as wide; with one long apical seta and three shorter preapical setae. Hypoproct ( Fig. 286 ) rectangular; more sclerotized laterally, thus appearing divided; finely hairy, with four basal sensory setae. Spermathecae ( Fig. 287 ) finely ridged; sclerotized ducts very long, four times the diameter of a spermatheca.

Variation. Colouration varies, with dark or pale stripes on the frons, and legs either uniformly or contrastingly coloured. Teneral individuals are light to reddish brown but possess the distinct iridescence.

Etymology. The species epithet is Latin for “a small gem,” given in reference to its iridescent abdomen, and elusive habits. Both authors searched intensively for this species at the type locality in 2009, but found only one specimen.

Type material. Holotype ♂, QCAZ. ECUADOR: Pichincha, Bellavista Cloud Forest Reserve , 12 km S Nanegalito, 28.x.1999, cloud forest, ridge trail leaf litter, R.S. Anderson.

Paratypes. ECUADOR: Pichincha, same label as holotype (7♂, 8♀, DEBU) ; same locality as holotype label, 2150 m, 30.x.1999, cloud forest, leaf litter, R.S. Anderson (4♂, 6♀, DEBU) ; same locality as holotype label, 0°1’13”S, 78°40’30”W, 2200 m, 9–13.v.2009, S.A. Marshall (♀, DEBU) ; Nono , 14 km NW, 2000 m, 24.x.1999, montane forest, leaf litter, R.S. Anderson (2♂, 2♀, DEBU) .

Comments. Aptilotella gemmula and A. ebenea are easily confused, externally differing solely by the presence of orbital bristles in the latter. The distiphallus of A. gemmula , however, has a prominent club-shaped sclerite, paired internal sclerites, and membrane-bearing ventral flanking sclerites, all of which are absent in A. ebenea . Additionally, each half of the female tergite 8 is much smaller and rounded compared to A. ebenea . The highly apomorphic hypandrium of A. gemmula is unlike any other in the genus.

Collection data suggest that in the type locality, A. gemmula may be commoner than A. ebenea , on average outnumbering the latter at least twofold. These species are also sympatric with A. pichinchensis , a distantly related species which differs by its larger size, the lack of iridescent colouration, hooked curved dorsal sclerites and welldeveloped tripartite ventral flanking sclerites.

Figures

FIGURE 48. Aptilotella gemmula Luk & Marshall, sp. n., male terminalia. Abbreviations: TPS = posteromedial triangular process of sternite 5, TUB = paired posteromedial tubercles of sternite 5.

FIGURES 46–47. Aptilotella gemmula Luk & Marshall, sp. n., male: 46—habitus, left lateral; 47—habitus, dorsal.

FIGURES 276–279. Aptilotella gemmula Luk & Marshall, sp. n.: 276—male terminalia, posterior; 277—male terminalia, left lateral; 278—male synsternite 6+7; 279—male sternite 5.

FIGURES 280–283. Aptilotella gemmula Luk & Marshall, sp. n.: 280—aedeagus with postgonites removed; 281— distiphallus, dorsal; 282—left postgonite; 283—hypandrium. Abbreviations: BP = basiphallus, CDS = curved dorsal sclerite, IS = internal sclerite, LFS = lateral flanking sclerite, VBS = ventrobasal sclerite, VFS = ventral flanking sclerite.

FIGURES 284–287. Aptilotella gemmula Luk & Marshall, sp. n.: 284—female terminalia, dorsal; 285—female terminalia, left lateral; 286—female terminalia, ventral; 287—spermathecae. Abbreviations: EP = epiproct, HP = hypoproct.