Threticus thelyceratus Curler & Moulton

Curler, Gregory R. & Moulton, John K., 2010, Descriptions of three new species of Psychodidae (Diptera) from the southeastern United States, Zootaxa 2524, pp. 51-62 : 57-61

Threticus thelyceratus Curler & Moulton sp. nov.

( Figs. 12–26 )

Diagnosis. Larva: Each antenna composed of 2 bulbous, hemispherical sensilla ( Figs. 22 , 25 ); postmentum without teeth. Pigment black, alveoli crowded dorsally and ventrally; anterior spiracles capitate; tergal plates nearly void of setae. Anal division with dorsal sclerite robust, encircling entire segment basally, conical apically; flabellar processes minute, respiratory fans inconspicuous. Pupa: Anal division with 3 spines on each side, 4 spines apically; dorsoapical spines hooked apically. Adult: Male eye bridge with 4 facet rows, eyes separated by 3 facet diameters. Interocular suture inverted Y-shaped. Male terminalia: parameres sclerotized, flanking aedeagus; one paramere filamentous, elongate, extending nearly beyond cercopodia; opposite paramere not extending beyond aedeagus, rostrate apically. Female terminalia: Subgenital plate with triangulate protuberances inserted anterolaterally; protuberances directed posteriorly; hypovalvae bilobed; lobes rounded, with posteromedial margins finely serrate; genital digit arising near base of hypovalvae, extending to ½ length of hypovalvae; genital duct about as wide as hypovalvae, with curled, horn-like projections ventrally.

Description. Larva ( Figs. 19–26 ): Measurements, instar IV (N = 2) total length 3.94 mm (3.85–4.02), cranial width 0.34 mm. Head capsule ovate, with genae broadly rounded. Each antenna composed of 2 bulbous, hemispherical sensilla ( Figs. 22 , 25 ). Labrum with multiple pectinate microtrichia and macrotrichia inserted ventrally, with paired, brush-like sensilla inserted anteriorly. Mandibles and maxilla typical of Threticus ; prostheca composed of 1 brush-like macrotrichium and 2 bipectinate macrotrichia. Postmentum straight, without teeth. Trunk: segmentation and arrangement of tergal plates typical of Psychodinae . Segments I–V parallel-sided, thorax and posterior segments gradually tapered. Integument black in color; alveoli numerous, hemispherical or flat, appearing crowded dorsally and ventrally; thoracic and abdominal segments with numerous elongate, brush-like alveoli ventrolaterally. Anterior spiracles capitate, inserted laterally on posterior annulus of prothorax, not extending beyond lateral margin. Tergal plates quadrangular, without protuberances, nearly void of setae. Anal division: dorsal sclerite robust, encircling anal division basally, conical apically, with few macrotrichia inserted dorsomedially, with 3 prominent macrotrichia inserted ventrolaterally on both sides; ventral flabellar processes minute, extending only slightly beyond dorsal sclerite; respiratory fans inconspicuous.

Pupa ( Figs. 17–18 ): Respiratory horn digitiform, constricted basally, with paired, longitudinal row of pores forming a pinna over the apical half; exterior surface appearing pitted dorsobasally, laterally, ventrally. Anal division with prominent, paired spines posterodorsally, posteroventrally; posterodorsal spines hooked apically; 2 prominent spines inserted dorsolaterally, 1 inserted ventrolaterally on each side; 2 pairs of macrotrichia, 1 pair of microtrichia inserted posterodorsally.

Adult Male ( Figs. 12–14, 16 ): Measurements, (N = 5) head width 0.47 mm (0.43–0.49), head length 0.45 mm (0.41–0.49), wing length 2.90 mm (2.50–3.15), wing width 1.12 mm (1–1.20), palpomere proportion: 1– 2.2–2.8–2.7. Eye bridge with 4 facet rows, separated by 3 facet diameters. Frontal scar patch as wide as frons, trilobed dorsally; lateral lobes divergent, truncate; median lobe divided medially, extending between eyes, terminating slightly below interocular suture. Interocular suture inverted Y-shaped. Antennae: scape about 1.25 times longer than wide; pedicel globular; flagellomere I with node elongate, fusiform basally; flagellomere XI with distal neck short, about equal in length to the following flagellomere; flagellomeres XII– XIV reduced, globular; ascoids sinuous, with one anterior and one posterior branch, present on flagellomeres I–XI. Mouthparts long for Psychodinae , extending slightly beyond basal palpomere; labellum bulbous, not wider than clypeus, without apical teeth. Wing: base of costa with 2 breaks, wings held horizontally over body in live fly; apex acute, R5 ending in apex; medial fork weakened, arising basal to radial fork, both arising basal to apex of CuA2. Terminalia: hypandrium narrow, quadrate, not extended posteriorly; epandrium trapezoidal, narrowing slightly posteriorly, bilobed posteroventrally, membranous posterodorsally, about as long as wide; gonocoxites about as long as wide, not extending beyond aedeagus or parameres, connected by ventral bridge basally, with elongate digitiform projections dorsobasally; digitiform projections directed medially; gonostyli evenly tapered from base to apex, gradually curved medially, with apices digitiform; aedeagus with basiphallus laterally compressed basally, connected to ventral gonocoxal bridge apically, articulated with distiphallus and parameres apically; distiphallus composed of single, acuminate sclerite; parameres sclerotized, flanking aedeagus; one paramere elongate, filamentous, extending nearly beyond cercopodia; opposite paramere short, not extending beyond aedeagus, beak-like apically, with apex curved laterally; cercopods about as long as epandrium, gradually tapered from base to apex, with 3 spathiform retinacula inserted dorsoapically. Tergite X semi-circular, about 1/4 as long as cercopodia.

Adult Female ( Fig. 15 ): Head as in male except with antennae and ascoids smaller. Wing as in male. Terminalia: Subgenital plate constricted posteriorly, with triangulate protuberances inserted anterolaterally; protuberances directed posteriorly; hypovalvae bilobed; lobes rounded, with posteromedial margins finely serrate; genital digit short, arising near base of hypovalvae, extending to ½ length of hypovalvae; genital duct as figured, about as wide as hypovalvae, with curled, horn-like projections ventrally.

Type material. Holotype [adult male]: U.S.A. NORTH CAROLINA: Haywood Co: GSMNP, Purchase Knob, 35°35'N 83°04'W, 22.iv–10.v.2008, coll. G.R. Curler, Malaise trap; deposited LACM. Specimen dissected, mounted on micro-slide. Allotype [adult female]: same data as holotype; deposited LACM. Specimen dissected, mounted on micro-slide. Paratypes: same data as holotype [3 adult males, 6 adult females (slides)]; same location as holotype, 15.v–1.vi.2007 [2 adult males, 3 adult females (slides)], 29.vi– 30.vii.2007 [1 adult female (slide)], 28.viii–29.ix.2007 [1 adult male, 2 adult females (slides)], 9–27.v.2008 [2 adult males, 4 adult females (slides)], 27.v–12.vi.2008 [2 adult males, 2 adult females (slides)] coll. G.R. Curler, Malaise trap; same location as holotype, 29.vi.2007 [1 male pupa (slide)], coll. G.R. Curler; Blue Ridge Parkway ( BLRI) @ Hornbuckle Valley overlook, 35°28’N 83°08’W, 30.vii.2006 [1 adult female (slide)], coll. G.R. Curler & J.K. Moulton, sweep net. Paratypes deposited in LACM, USNM, and UTK.

Other records. U.S.A. NORTH CAROLINA: Haywood Co: BLRI @ Woodfin Cascades, 35°27’20”N 83°5’40”W, 26.vii.2005 [1 adult male], coll. J.K. Moulton, sweep net; same location 22.vii.2006 [3 adult females], coll. G.R. Curler, aspirator; same location 30.vii.2006 [2 adult females] coll. G.R. Curler & J.K. Moulton, mercury vapor light; BLRI @ Hornbuckle Valley overlook, 35°28’N 83°08’W, 30.vii.2006 [2 adult males], coll. G.R. Curler & J.K. Moulton, sweep net; BLRI @ East Fork overlook, 35°19’N 82°50’W, 18.viii.2006 [1 adult male, 1 adult female], coll. G.R. Curler & J.K. Moulton, sweep net; BLRI near Log Hollow overlook, 35°21’20”N 82°48’50”W, 12.vii.2007 [1 adult male, 2 adult females], coll. J.L. Robinson, sweep net.

Phenology. Adult T. thelyceratus were collected from mid May to late August, with the greatest number of captures in mid-summer.

Distribution. Collected from multiple locations in western North Carolina.

Remarks. Threticus thelyceratus is one of two Nearctic species of Threticus . It is sympatric with, but easily separable from T. bicolor (Banks) by the shape of the parameres, particularly the elongate, filamentous paramere in the male and the shape of the subgenital plate with protuberances and genital duct with hornshaped dorsal projections in the female. As illustrated by Wagner (1984), the male terminalia of Threticus species exhibits mirrored symmetry in some specimens, and can appear different in some specimens due to the aedeagus and parameres being retracted into the abdomen. Both of the aforementioned conditions were observed in T. thelyceratus , but most specimens died with the aedeagus and parameres fully exerted. Larvae of this species were collected from in between moist decaying leaves, which were lying along the margin of a first order stream.

Figures

FIGURES 12 – 18. Threticus thelyceratus Curler & Moulton sp. nov. 12. Male head, frontal view. 13. Male wing. 14. Male terminalia, dorsal view. 1 5. Female terminalia, subgenital plate removed, showing internal structure, ventral view. 16. Male right antennal flagellomere 1, frontal view. 17. Right respiratory horn of pupa, dorsal view. 18. Anal division of pupa, dorsal view. Scale bars = 0.05 mm (16 – 17), 0.1 mm (18), 0.125 mm (15), 0.25 mm (12, 14), 0.5 mm (13). (abbreviations: aed = aedeagus; ds = dorsal spine; gdct = genital duct; ls = lateral spine; pm = paramere; prt = protuberance; sgp = subgenital plate; vs = ventral spine).

FIGURES 19 – 24. Scanning electron micrographs of larval Threticus thelyceratus Curler & Moulton sp. nov. 19. Habitus, dorsolateral view. 20. Abdominal segment VII and anal division, lateral view. 21. Right anterior spiracle, dorsal view. 22. Right antenna, dorsal view. 23. Left side of meso and metathorax, detail of alveoli, ventral view. 24. Head, pro- and mesothorax, dorsal view. Scale bars = 10 µ (21 – 22), 20 µ (23), 100 µ (20, 24), 200 µ (19).

FIGURES 25 – 26. Scanning electron micrographs of larval Threticus thelyceratus Curler & Moulton sp. nov. 25. Mouthparts, ventral view. 26. Mouthparts, left side enlarged, ventral view. Scale bars = 10 µ (24), 20 µ (25). (abbreviations: ant = antenna; lr = labrum; md = mandible; mx = maxilla; pt = prostheca).