Aptilotella quadrata 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 : 40-42

Aptilotella quadrata Luk & Marshall , sp. n.

Figures 3 and 288–294

Description. Habitus as in Figure 3 . Body length 1.1–1.6 mm. Head ground color yellow. Frons finely rugose; pale areas attaining the occiput but not the anterior margin; brown medial stripes each about one-seventh the width of frons, with narrow orange borders; dark brown orbital stripes confined to posterior corners of frons, their orange borders confluent with the medial stripes; ocular emargination with pruinose patch. Ocellar tubercle scarcely raised; ocellar bristle two-thirds the length of frons. Orbital bristle absent; orbital setulae inconspicuous, in two pairs. Interfrontal setae inconspicuous, in three pairs. Face shining; facial tubercle bulbous; gena with black ventral margin. Antenna brown, first flagellomere paler in basal half. Occiput with dark brown margin. Scutum and scutellum black, shining. Scutum with only a few short setae. Scutellum bare; 2.4 times wider than long, 0.6 times the width of scutum. Apical scutellar bristles 2.5 times as long as basal. Pleuron black; anepisternum and anepimeron with pale pruinose stripe. Legs orange; coxa black; femur dark orange, basal half of hind femur brown; mid tibia dark brown, with a single proximal anterodorsal bristle. Wing rudiment dark brown. Abdomen black, shining; tergites distally with a row of evenly-spaced, short setae; sternites microtrichose. Cercus and surstylus orange.

Male terminalia. Sternite 5 ( Fig. 291 ) narrow and asymmetrical; posteromedial half shallowly emarginate; two long, apically rounded lobes arising in posteromedial quarter, their interior margin setaeous. Synsternite 6+7 ( Fig. 290 ) with humped margin before medial bridge; interior surface of medial bridge with free, saddle-shaped sclerite. Cercus ( Figs. 288, 289 ) curved, twice as long as basal width; base triangular, with four long setae near outer margin, and a much longer marginal seta subequal to the length of cercus; distal three-fifths slender, bearing two small, well-separated sensory setae. Surstylus ( Figs. 288, 289 ) horseshoe-shaped, basally enlarged; anterior lobe apically dilated and truncate, with scattered sensory setae; posterior lobe with setaceous outer margin, apically bearing three large, articulated, claw-like spines. Postgonite ( Fig. 293 ) sinuate; descending arm 0.6 times the total length, of uniform width and slightly bent midway, with two distal sensory setae; articulatory process for pregonite broad, rounded; articulatory process for basiphallus knobbed. Hypandrium ( Fig. 294 ) with medial rod straight and apically truncate; hypandrial arms apparently fused to broad base, very slender, with the apex truncate and bent back; pregonite minute and squared. Aedeagus as in Figure 292 . Basiphallus compressed, arched, basal lobe projecting into distiphallus; articulatory process for postgonite pointed, erect. Ejaculatory apodeme short. Lateral flanking sclerites with dark dorsal and ventral margins, broadly fused both ventro- and dorsobasally; apicodorsally armed with minute sclerotized teeth. Dorsal sclerite constricted medially, its sides forming a channel; apex laterally lobed and bearing minute sclerotized teeth. Ventral flanking sclerites with the basal article fused along ventrodistal margin of lateral flanking sclerite; the spatulate medial article sharply pointed beneath the basal article; the concave distal article fused to the medial article and sharply pointed over it.

Female terminalia. Not examined; retracted from view in the single female specimen.

Variation. The two specimens from the “trail to Cerro Chirripó” have the dark genal band continuing through the clypeus, a thick dark band across the facial excavation, dark brown legs, and two anterodorsal bristles on the mid tibia. Although otherwise identical to the type material, both are females and cannot be positively identified as Aptilotella quadrata .

Etymology. The species epithet describes the roughly squared tergite 1 plate, a defining character of this species and sister species.

Type material. Holotype ♂, INBC. COSTA RICA: Highway 2, km 96, 3200 m, 7–13.iv.1985, cloud forest (oak), pan trap, H. Goulet and L. Masner.

Paratypes. COSTA RICA: San José, 2 km E Villa Mills , 9°33’30”N, 83°42’W, 2800 m, 26.vi.1997, second growth oak forest litter, R.S. Anderson (♀, DEBU) ; same as previous label but at 2750 m, 15.ii.1998 (♂, DEBU) ; Cerro Chirripó, Base Crestones , 3350 m, 25.vi.1999, elfin forest, leaf litter, R.S. Anderson (♂, DEBU) .

Other material examined. COSTA RICA: Cartago, Cerro Chirripó , trail to, 2800 m, 27.vi.1999, mixed oak forest, leaf litter, R.S. Anderson (2♀) .

Comments. Externally, Aptilotella quadrata and A. umbracatus are recognizable by their very shiny, nearly hairless body, completely separated lateral remnant of tergite 1, and unicolorous legs with one or two long anterodorsal bristles on the mid tibia. They are also distinguished from all other Aptilotella by the distiphallus with a prominent dorsal sclerite and articulated medial and distal articles of the spoon-shaped ventral flanking sclerites, the loss of the ventrobasal sclerite, and a spindle-shaped ejaculatory apodeme.

Few members of the genus are as large and robust as Aptilotella quadrata , and not even the more slender A. involucris possesses such a prominently bilobed male sternite. A female specimen of an undescribed species, collected at carrion with A. umbracatus in Panama, is superficially similar to A. quadrata but lacks markings on the frons.

Figures

FIGURE 3. Aptilotella quadrata Luk & Marshall, sp. n., holotype male.

FIGURES 288–291. Aptilotella quadrata Luk & Marshall, sp. n.: 288—male terminalia, posterior; 289—male terminalia, left lateral; 290—male synsternite 6+7; 291—male sternite 5.

FIGURES 292–294. Aptilotella quadrata Luk & Marshall, sp. n.: 292—aedeagus with postgonites removed; 293—left postgonite; 294—hypandrium. Abbreviations: BP = basiphallus, DS = dorsal sclerite, LFS = lateral flanking sclerite, VFS = ventral flanking sclerite.