Aptilotella quatuorchela 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 : 33-34

Aptilotella quatuorchela Luk & Marshall , sp. n.

Figures 37–39 , and 210–222

Description. Habitus as in Figures 37 and 38 . Body length 1.3–1.4 mm. Head ground color orange. Frons finely rugose except for shining posterior quarter of orbital plate; pale areas silvery, not attaining the anterior margin, the lateral pair converging on occiput; brown medial stripes each about one-fourth the width of frons; brown orbital stripes each half the width of medial stripe; ocular emargination with small silvery spot. Ocellar tubercle slightly raised; ocelli present; ocellar bristle two-fifths the length of frons. Orbital bristle present; orbital setulae minute, in three pairs. Interfrontal setae in two pairs. Lunule with silvery spot; face shining; facial excavation with a broad silvery-white band continuing onto anterior half of gena; clypeus brown; gena weakly shining, margin dark, setaceous. Antenna orange. Scutum and scutellum dark reddish-brown, shining. Scutum deeply creased along posterolateral margin; uniformly setose, microtrichose except for crease. Scutellum finely microtrichose; flat, twice wider than long, 0.6 times the width of scutum. Apical scutellar bristles 1.4 times as long as basal. Pleuron dark brown. Legs orange in males, dark brown with light brown tarsi in females; mid and hind coxae black; mid tibia with two anterodorsal and one distal posterodorsal bristle, in males with a posteroventral comb of stout setae ( Fig. 222 ). Wing rudiment light brown. Abdomen black, shining; uniformly finely microtrichose; tergites each with two rows of long yellow setae; sternites with shorter setae. Epandrium and synsternite 6+7 dark reddish-brown; cercus and surstylus orange.

Male terminalia. Sternite 5 ( Figs. 39 , 213 ) posteromedially with a V-shaped marginal notch inside a lightly sclerotized concavity, this area surrounded by many setae and a marginal sclerotized stub. Synsternite 6+7 ( Fig. 212 ) very robust, 0.8 times as long as wide; medial bridge broad, posteromedial margin with a membranous protuberance. Tab-like piece ( Figs. 39 , 213 ) consisting of a pair of heavily sclerotized saddle-shaped processes fused by a broad, thin strap that articulates within the notch of sternite 5. Cercus ( Figs. 39 , 210, 211 ) gradually tapering, 2.5 times as long as basal width; apex truncate; clothed in setulae; one long seta present at base, another near lateral margin at the basal third, distal half toward apex with 4–5 setae of decreasing size. Surstylus ( Figs. 39 , 210, 211 ) a compressed cone, posteriorly expanded into a broadly rounded lobe bearing setae of various sizes; base above the lobe with elongate protuberance bearing several small ventral setae, one long lateral seta, and one apical seta. Postgonite ( Fig. 216 ) curved; descending arm slender, slightly sinuous, anterior margin with three evenly spaced sensory setae; articulatory process for pregonite triangular; articulatory process for basiphallus stalked, knobbed with small anterior bump. Hypandrium ( Fig. 217 ) with medial rod straight and apically truncate; posteromedial fork narrow, divergent, and webbed; hypandrial arms oblong, the left arm broader, with blunt marginal tooth at anterodistal third; pregonite irregularly clavate, four-fifths length of hypandrial arm. Aedeagus as in Figures 214 and 215 . Basiphallus compressed, arched; articulatory process for postgonite broad and erect. Ejaculatory apodeme discoid, apically slightly upturned. Ventrobasal sclerite divided. Lateral flanking sclerites broadly fused ventrobasally; dorsal margin rolled, straight; distal margin squarely excavated in middle. Ventral flanking sclerites heavily sclerotized; the spade-shaped sclerite distally compressed, fused to one another by a sclerotized U-shaped belt, and dorsally supporting a loose suspension of small denticles; the elongate medial article sharply pointed before ventromedial margin of spatulate sclerite and rising next to it; the bilobed distal article originating from beneath medial article, pincer-like in appearance due to the inward arching of the broad outer lobe against the slimmer inner lobe, the latter bearing a prominent triangular lobe on its outer face. Paired medial sclerites originating from beneath spatulate sclerite, similarly shaped but slimmer.

Female terminalia. Epiproct ( Figs. 218, 219 ) triangular, apically rounded and microtrichose. Each half of tergite 8 ( Figs. 218–220 ) convex, upper third bent and shining; margin rounded, dorsally indented to align with epiproct; sparsely setaceous. Cercus 2.5 times as long as wide; with one long apical seta and several preapical setae. Hypoproct ( Fig. 220 ) very pale, triangular, basal corners laterally drawn out into triangular lobe; apex microtrichose and with two pairs of setae. Spermathecae ( Fig. 221 ) simple; length of sclerotized ducts more than twice the diameter of a spermatheca.

Variation. The colouration of the legs is generally considerably darker and contrasting in the females, compared to uniform orange in most, but not all males. Teneral specimens have a uniformly brown body.

Etymology. The species epithet is derived from the Latin quattuor, “four,” and chela, “claw,” a description of the claw-like array club-shaped sclerites, paired medial sclerites, and the distal article of each ventral flanking sclerite in the distiphallus.

Type material. Holotype ♂, UNAM. MEXICO: Chiapas, El Triunfo Reserve, Pico El Triunfo , 15°40’10”N, 92°48’42”W, 2400 m, 16–21.xi.2001, cloud forest, leaf litter, R.S. Anderson.

Paratypes. MEXICO: Chiapas, same label as holotype (12♂, 6♀, DEBU; 4♂, 3♀, UNAM) ; Custepec , 3.5 km ESE, 15°43’N, 92°56’W, 1800 m, 17.vii.2007, M.G. Branstetter (♂, DEBU) ; Custepec , 4 km SE, 15°42’37”N, 92°55’56”W, 1960 m, 18.v.2008, mixed hardwood forest, ex. sifted leaf litter, R.S. Anderson (♂, DEBU) ; Custepec , 4 km SE, 15°42’28”N, 92°55’52”W, 2150 m, 21.v.2008, ridge oak forest, ex. sifted leaf litter, R.S. Anderson (♀, DEBU) .

Comments. Aptilotella quatuorchela and A. gloriosa occur sympatrically and appear to be equally common within their range. The male genitalia of A. quatuorchela differs from that of its boldly coloured cousin and A. andersoni by the long and stout cercus, fused saddle-shaped tab-like piece of sternite 5, weakly arched basiphallus, and ventral flanking sclerites with strongly ascending articles and a chelate distal article. This is also the only species of the three to possess a posteroventral setal comb on the male mid tibia. The sexes are readily distinguished by the leg colour, which is orange in males and dark brown with brown tarsi in females.

Figures

FIGURE 39. Aptilotella quatuorchela Luk & Marshall, sp. n., male terminalia. Abbreviations: CER = cercus, MBS = marginal lobe of sternite 5, SUR = surstylus, TLP = tab-like piece of sternite 5.

FIGURES 37–38. Aptilotella quatuorchela Luk & Marshall, sp. n., male: 37—habitus, left lateral; 38—habitus, dorsal.

FIGURES 218–222. Aptilotella quatuorchela Luk & Marshall, sp. n.: 218—female terminalia, dorsal; 219—female terminalia, left lateral; 220—female terminalia, ventral; 221—spermathecae; 222—male mid tibia, anterior. Abbreviations: EP = epiproct, HP = hypoproct.

FIGURES 210–213. Aptilotella quatuorchela Luk & Marshall, sp. n.: 210—male terminalia, posterior; 211—male terminalia, left lateral; 212—male synsternite 6+7; 213—male sternite 5.

FIGURES 214–217. Aptilotella quatuorchela Luk & Marshall, sp. n.: 214—aedeagus with postgonites removed; 215— distiphallus, dorsal; 216—left postgonite; 217—hypandrium. Abbreviations: BP = basiphallus, CSS = club-shaped sclerite, LFS = lateral flanking sclerite, MPS = medial paired sclerites, VBS = ventrobasal sclerite, VDA = distal article of ventral flanking sclerite, VMA = medial article of ventral flanking sclerite.