Trichomyia nebulicola, Ibáñez-Bernal, Sergio, 2004

Ibáñez-Bernal, Sergio, 2004, Notes on the known species of Trichomyia Haliday of Mexico, with the establishment of a synonymy and the description of a new species (Diptera: Psychodidae), Zootaxa 523, pp. 1-14 : 8-13

Trichomyia nebulicola sp. nov. Ibáñez­Bernal

( Figs. 21–35 )

Diagnosis. Male easily distinguishable by the triangular outline of the gonocoxite with the external lobular projection and concave internal margin, the gonostyle bifid and composed of a dorsal triangular mandible­like portion and a ventral portion strongly curved mesally to form a long slender sickle­like projection with apex basally directed and bearing a short basal tooth ( Fig. 27 ); in the female by the pyramidal­truncate lobe of the subgenital plate, where the lateral margins converge toward the apex, and the posterior margin is trilobate with each lobe triangular ( Fig. 35 ).

Male description ( Figs. 21–28 ). Head slightly wider than long, 0.81 as high as wide, subcircular in frontal view; vertex slightly elevated; vertex and frontal area regularly covered with setae alveoli and four pairs of transparent sensilla smaller than the setae alveoli near the midline; supraocular row of large alveoli irregular; fronto­clypeus with a patch of setae alveoli ( Fig. 21 ). Palpus with 4 palpomeres, the first two divided by a clear line and both with a patch of sensory rods on internal surface; palpomere proportions: 1.00: 0.83: 1.11: 2.00 ( Fig. 22 ). Antennal scape subcylindrical, pedicel subspherical and slightly longer than scape ( Fig. 23 ); flagellum with 13 pyriform and symmetric unrecessed flagellomeres, progressively decreasing in length toward the apex; each flagellomere, with a pair of long gently curved digitate ascoids that reach the basal portion of the succeeding article ( Fig. 23 ). Apical flagellomere with a small rounded apiculus, its base very constricted ( Fig. 24 ). Thorax: Upper posterior portion of anepisternum with a patch of numerous seta alveoli, separated from each other by about one diameter of alveolus. Wing as long as 2.46 its width, basal cells infuscated; Sc marked by infuscation with only one or two setae alveoli; R1 originates at same level than R2+3+R4 fork; radial fork basal from wing center but apical to median fork; R4 ending just behind wing tip; base of M2 obsolete but nearly touching M1; CuA2 ending distad to radial fork ( Fig. 25 ). Terminalia ( Figs. 26– 27 ) with gonocoxites fused together above aedeagus by a relatively narrow bridge, laterally expanded as a rounded posteriorly directed lobe, with the apex projected behind the base of gonostylus; as a consequence of the development of the gonocoxite lobe, the gonostylus may originate very close to the midline ( Fig. 28 ); gonostylus complex and bifid; the dorsal portion mandible­like and very sclerotized, with acute short apex directed toward the midline, the ventral portion strongly curved mesally and forming a long slender sicklelike projection with apex basally directed and bearing a short basal tooth ( Figs. 27, 28 ). Aedeagus simple and clear, parallel sided with truncate apex; basal apodeme more slender and about 0.8 as long as aedeagus, with base nearly globular and well differentiated. Parameres with basal portion broad and laminar, internally following the lateral margin of aedeagus as far as middle of the structure, abruptly turned forward as a gentle curve to finish as a sickle­like projection with apex directed toward the midline ( Fig. 28 ). Epandrium slender and nude. Surstylus slightly longer than basal width, internally folded in apical half to form a triangular crease, lacking specialized structures ( Fig. 26 ). Tenth tergite long and digitate ( Fig. 26 ).

Measurements. Head height: 0.379 ±0.014 (0.36–0.40) n=6; head width: 0.3853 ±0.016 (0.38–0.42) n=6; palpus length: 0.170 ±0.006 (0.160–0.176) n= 5; antenna length: 1.114 ±0.032 (1.08–1.14) n=3; wing length: 1.690 ±0.065 (1.61–1.77) n=6; wing width: 0.678 ±0.031 (0.63–0.72) n=6; R2+3+R4: 0.093 ±0.003 (0.090–0.096) n=6; R2+3: 0.753 ±0.073 (0.616–0.832) n=6; gonocoxite length (from base to lobe apex): 0.108 ±0.014 (0.09–0.13) n=6; gonostylus length (dorsal portion): 0.053 ±0.002 (0.048–0.056) n=6; surstylus length: 0.097 ±0.002 (0.094–0.100) n=6.

Female description ( Figs. 29–35 ). Same as male, except for the following characteristics: palpomere proportions: 1.0: 0.83: 1.25: 2.5 ( Fig. 32 ); antenna and ascoids as figured ( Figs. 29–31 ). Anepisternum with setae alveoli along posterior margin separated by more than two alveoli diameters. Wing as long as 3X its width ( Fig. 33 ). Terminalia as figured ( Figs. 34–35 ); subgenital plate with setae alveoli evenly distributed over the surface, the apical lobe pyramidal, truncate, ending in three triangular projections of which the median is the largest, and bearing 16–18 marginal, simple and long setae; lateral margins of apical lobe convergent toward the apex ( Fig. 35 ). Internal sclerotizations in the form of two external ear­shaped laminae and a pair of internal rods finely striated over most of their surface, except the external margin; internal rods slightly wider at base, with a short sclerotization at external margin near the apex connecting the subgenital plate, and proximally in contact with the plate that gives rise to the pair of spermathecal ducts; basal spermathecal apodeme “T”­shaped ( Fig. 34 ). Spermathecal duct annulated, slightly increasing in diameter towards apex; duct ending in a cylindrical structure which is reinforced by a well sclerotized ring and a dome­shaped structure ( Fig. 34 ). Tergite 9 nude at middle. Cercus short and nearly rounded in lateral view ( Fig. 35 ).

Measurements (n=1). Head height: 0.37; head width: 0.40; antenna length: 0.92; palpus length: 0.14; wing length: 1.57; wing width: 0.52; R2+3+R4: 0.07; R2+3: 0.67; subgenital plate length: 0.14; cercus length: 0.12.

Material examined. Holotype male: Mexico, Veracruz, Xalapa Municipality, Xalapa, Fraccionamiento Coapexpan, 15–16, February­2000. Malaise trap at night (18:00–08:00 hr), S. Ibáñez­Bernal, col. Allotype female: same data as holotype; Paratypes: 5 males: same data as holotype. Holotype, allotype and 2 male paratypes deposited in IEXA collection, Xalapa, Veracruz, Mexico, 3 male paratypes deposited in Los Angeles County Museum of Natural History, California, USA. All specimens slide­mounted with Euparal.

Etymology. From Latin nebulosa, mist, and alicola, inhabitant, reflecting that this species was captured in a cloud forest of central Veracruz, Mexico.

Comments. The male of T. nebulicola is easily distinguished by the gonopod, specifically by the gonocoxite externally projected as a blunt lobe and the internal margin somewhat concave which gives the structure a triangular appearance in dorso­ventral view ( Fig. 27 ), and by the gonostylus complex formed by two branches, one shorter, compact and triangular, and the other with a very sharp and slightly curved projection with a basal blunt tooth ( Figs. 27, 28 ). The female of this species is very similar to T. brevitarsa , and can be distinguished only by the shape of the apical lobe of subgenital plate that has the lateral margins convergent toward the apex ( Fig. 35 ). The internal sclerotizations are extremely similar in both species, as well as the spermathecal ducts ( Fig. 34 ).

It is expected that the strong similarity of the female of T. nebulicola with that of T. brevitarsa , the subgenotype of Trichomyia (Opisthotrichomyia) , should be consistent in the case of males. Yet, the male of T. nebulicola lacks one of the two synapomorphies proposed by Bravo (2001) (the presence of a setae­bearing internal lobe of the gonocoxite).

Thus, there is no need to assign the species to any extant subgenera until more information becomes available.

Figures

FIGURES 21 – 28. Trichomyia nebulicola Ibáñez­Bernal, sp. nov. (holotype) male. 21: Head in frontal view (right palpus and left flagellum removed); 22: left palpus; 23: scape, pedicel and basal three flagellomeres of antenna; 24: apical flagellomeres of antenna; 25: wing; 26 – 28: terminalia. 26: tergite 10 and surstylus; 27: right gonocoxite and gonostylus; 28: right gonopod, aedeagus and parameres.

FIGURES 29 – 35. Trichomyia nebulicola Ibáñez­Bernal, sp. nov. (allotype) female. 29: scape, pedicel and first three flagellomeres; 30: flagellomeres 4 – 10; 31: apical flagellomeres of antenna; 32: right palpus; 33: wing; 34 – 35: terminalia, 34: internal structures and spermathecal ducts, dorsoventral view; 35: subgenital plate and cercus.