Aptilotella diffisa 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 : 25-26

Aptilotella diffisa Luk & Marshall , sp. n.

Figures 19–21 , and 138–148

Description. Habitus as in Figures 19 and 20 . Body length 1.2–1.3 mm. Head ground color yellow-orange. Frons finely rugose; pale areas silvery, the lateral pair sharply converging on occiput; brown medial stripes each about one-fourth the width of frons, converging along the anterior margin, darkening posteriorly; brown orbital stripes each half the width of medial stripe. Ocellar tubercle slightly raised; ocelli present; ocellar bristle two-fifths the length of frons. Orbital bristle present; orbital setulae minute, in seven pairs. Interfrontal setae in two pairs. Face weakly shining; facial excavation with a broad silvery-white band, margin with a small medial notch; gena dull, finely rugose, lower margin darkened and setaceous. Antenna yellow. Occiput brown. Scutum and scutellum dark reddish-brown, shining. Scutum convex, deeply creased along posterolateral margin; uniformly setose, microtrichose except for crease. Scutellum uniformly microtrichose; flat, twice wider than long, 0.7 times the width of scutum. Scutellar bristles subequal in length. Pleuron dark brown, weakly shining. Legs yellow; coxae and mid and hind femora dark brown; mid tibia with two anterodorsal and one distal posterodorsal bristle. Wing rudiment brown. Abdomen black, shining; tergites uniformly setose and microtrichose; sternites finely microtrichose. Epandrium and synsternite 6+7 dark reddish-brown; cercus yellow.

Male terminalia. Sternite 5 ( Figs. 21 , 141 ) lunate, anteromedially grooved; posteromedial third concave and emarginate, bearing stout setae, flanked by numerous long and short setae, and lined by a hair-fringed membrane; periphery of emargination giving rise to a pair of curved cercal claspers. Synsternite 6+7 ( Fig. 140 ) posteriorly with two triangular lobes arching over medial bridge; posteromedially with a free, two-armed structure with hooked ends. Anal aperture ( Fig. 138 ) closed by narrow bridge. Cercus ( Figs. 21 , 138, 139 ) slender, shallowly S-shaped as in profile of sternite 5; seta at mid-length about half as long as the cercus; outer margin with five evenly spaced setae between long seta and apex. Surstylus ( Figs. 138, 139 ) saddle-shaped; ventral face with several setae; posteriorly with a protuberance bearing 6–7 setae. Postgonite ( Fig. 143 ) cylindroid, 1.3 times as long as wide; descending arm very short, slightly curved, with several marginal sensory setae; articulatory process for pregonite reduced; articulatory process for basiphallus only slightly protruding. Hypandrium ( Fig. 144 ) with medial rod slanted to the right, apically dilated and twisted left, membrane medially produced into a triangle; posteromedial fork thick, rounded and divergent; hypandrial arms long and irregular, the left arm constricted and triangular in distal third; pregonite ovate, apically with a small curved tooth. Aedeagus as in Figure 142 . Basiphallus cylindrical, arched; articulatory process for postgonite twisted and divergent. Ventrobasal sclerite divided. Lateral flanking sclerite fused ventrobasally by a very narrow bridge; dorsal margin rolled, straight; basal and distal margins excavated; distal margin giving rise to an open-ended, membranous sac clothed in dense rows of denticles. Ventral flanking sclerites with the basal article fused along entire ventral margin of lateral flanking sclerite, bearing a ventrodistal tooth and a weak dorsal arm; the dark cylindrical medial article broadened basally to articulate with basal article and meeting ventral margin of lateral flanking sclerite; the membranous distal article irregularly spade-shaped, with sclerotized elliptical plate articulating with medial article. Triangular dorsal sclerites originating from above membranous sac and similarly clothed in denticles, with two more pairs of internal sclerites (not illustrated) beneath them. Triangular internal sclerites articulating with asymmetrical saddle-shaped sclerite, which descends between the distal articles of ventral flanking sclerites. Ventral plate-like sclerites (not illustrated) diamond-shaped, posterior to saddle-shaped sclerite.

Female terminalia. Epiproct ( Figs. 145, 146 ) rectangular, sclerotized. Each half of tergite 8 ( Figs. 146, 147 ) weakly convex; apex triangular, rounded; with several setae. Tergite 7 posteromedially notched. Cercus 3.5 times as long as wide; with one long apical seta and several preapical setae. Hypoproct ( Figs. 146, 147 ) divided into a pair of microtrichose discs with two setae. Spermathecae ( Fig. 148 ) simple; length of sclerotized ducts less than twice the diameter of a spermatheca.

Variation. Teneral specimens have a uniformly reddish-brown body. The silvery facial stripe occasionally diffuses into the gena. Tergite 8 in some females is broadly rounded rather than triangular.

Etymology. The species epithet is from the Latin diffido, “to distrust,” referring to the ambiguous structure of the complex distiphallus.

Type material. Holotype ♂, INBC. COSTA RICA: Cartago, Llano Bonito, trail to Cerro Chirripó , 27.vi.1999, cloud forest, leaf litter, R.S. Anderson.

Paratypes. COSTA RICA: Cartago, same label as holotype (4♂, ♀, DEBU) ; San José, km 117, Pan American Highway , 19 km N San Isidro, 9°28’N, 83°40’W, 26.vi.1997, cloud forest, litter, R.S. Anderson (3♂, 5♀, DEBU) ; same locality as previous label, 1800 m, 20.vi.1997, R.S. Anderson (5♂, 3♀, DEBU) ; same locality as previous label but without coordinates, 15.ii.1998 (♀, DEBU) ; Estación Cuerici , 4.6 km E Villa Mills, 9°34’N, 83°40’W, 2600 m, 26.vi.1997, oak forest, litter, R.S. Anderson (2♀, DEBU) ; same data as previous label but from mixed oak Alnus forest (3♂, ♀, DEBU) .

Comments. Aptilotella diffisa closely resembles members of the A. corona species group, but its aedeagus is very different. The complex distiphallus is comparable to that of A. involucris , particularly in the arrangement of ventral sclerites. The lopsided saddle-shaped sclerite is unique to this species.

Figures

FIGURE 21. Aptilotella diffisa Luk & Marshall, sp. n., male terminalia. Abbreviations: CER = cercus, CLP = clasper-like process of sternite 5.

FIGURES 19–20. Aptilotella diffisa Luk & Marshall, sp. n., male: 19—habitus, left lateral; 20—habitus, dorsal.

FIGURES 138–141. Aptilotella diffisa Luk & Marshall, sp. n.: 138—male terminalia, posterior; 139—male terminalia, left lateral; 140—male synsternite 6+7; 141—male sternite 5.

FIGURES 142–144. Aptilotella diffisa Luk & Marshall, sp. n.: 142—aedeagus with postgonites removed; 143—left postgonite; 144—hypandrium. Abbreviations: BP = basiphallus, LFS = lateral flanking sclerite, MS = membranous sac, SSS = saddle-shaped sclerite, TDS = triangular dorsal sclerite, TIS = triangular internal sclerite, VBA = basal article of ventral flanking sclerite, VBS = ventrobasal sclerite, VDA = distal article of ventral flanking sclerite, VMA = medial article of ventral flanking sclerite.

FIGURES 145–148. Aptilotella diffisa Luk & Marshall, sp. n.: 145—female terminalia, dorsal; 146—female terminalia, left lateral; 147—female terminalia, ventral; 148—spermathecae. Abbreviations: EP = epiproct, HP = hypoproct.