Lygistorrhina (Probolaeus) borkenti Huerta & Ibáñez-Bernal, 2008

Huerta, Heron & Ibañez-Bernal, Sergio, 2008, The family Lygistorrhinidae (Diptera: Sciaroidea) in Mexico and the description of two new species, Zootaxa 1808, pp. 44-52 : 49-51

Lygistorrhina (Probolaeus) borkenti Huerta & Ibáñez-Bernal sp. nov.

( Figs. 13–19 )

Type material. Holotype male. Labeled: Mexico, Parque Nacional “Lagunas de Zempoala”, límite Morelos, 14.VII.1990, aerial net, Ibáñez-Bernal S., col. (Specimen dissected and mounted on microscopic slide, deposited in CAIM).

Paratypes: 4 males: Same data as holotype (2 specimens deposited in CAIM, 2 specimens deposited in IEXA). (One specimen dissected and mounted on microscopic slide, the other three pinned).

Diagnosis. Abdomen of male with basal pale yellow bands on tergites 2–4, tergites 1 and 5–7 dark brown; antennae dark; flagellum length 1.10; coxae dark; hind femur with basal half pale yellow, apical half dark brown; hind tibia basal half pale yellow, apical half dark brown; wing length 3.84; aedeagal complex membranous and rounded.

Description. Male. General body coloration dark, length ca. 5.0; head dichoptic, eye facets of equal size and with interfacetal pubescence. Median ocellus present. Proboscis longer than hind femur. Palpus length ca. 1.76, as long as labellum. Antennae dark, length 1.2, or 1.3X the head height, with 14 unicolorous flagellomeres, each longer than wide and with distinct reticulations, and scattered seta-like sensilla, flagellum length 1.10; apical flagellomere length 0.13.

Thorax ( Fig. 13 ) dark, scutum slightly convex, sparsely covered with short setae; scutellum with 8 setae; mediotergite bare; supra-alar and notopleural setae 10–12; anterior pronotum and episternum setose; anepisternum bare; katepisternum with ventral margin slightly curved, laterotergite lobe-like posteroventrally with 17 setae; metepisternum with membranous aspect, delimited by a sclerotized line. All coxae dark with sparse setae; length 0.78, 0.64, and 0.50, respectively; fore and midleg femora and tibiae pale yellow, but femora very faint pigmented sub-basally; hind femur ( Fig. 16 ) with basal half pale yellow, apical half dark brown, length 1.8; hind tibia with basal half pale yellow, and apical half dark brown, length 2.72; femur/tibia proportion: 0.6; tarsomeres brown, length I–V: 1.46, 0.69, 0.51, 0.38, 0.25; tibial spurs formula 1:1:2; hind tibial spurs microtrichose, subequal in size, inner spur 1.4X the size of outer; tibial setulae in palisade rows; tarsal claws of fore and mid legs curved, with diminutive projection basally, sharply curved with tip arched; hind tarsal claws length 0.012, slightly curved at apex, with sharp tip; empodia present. Wing ( Figs. 14, 15 ) length 3.84, width 1.48; membrane densely covered with microtrichiae on whole surface, with apical darker spot situated at junction of veins R5 and C; Sc joining C, h not oblique; R1 setose, as long as ca. 0.46X the length of wing; R5 setose except the basal portion; C ending midway between apices of R5 and M1; Rs absent; only apical third of veins M1 and M2 present; length of M1 1.4, M2 1.3; CuA1 and CuA2 not connected in distal fork, length of CuA1 1.2; CuA2 straight but somewhat curved at the level where CuA1 begins; CuP very close and parallel to stem of CuA2; anal lobe well developed. Halter yellow.

Abdomen with basal pale yellow bands on tergites 2–4, tergites 1 and 5–7 and genitalia dark brown; abdomen length ca. 4.8, length of abdomen in relation to wing 0.85; sternite 8 rounded at apex. Genitalia as in Figs. 17 ; and 18; tergite 9 length 0.29, longer than wide, with rounded apical margin provided of aggregation of thickened setae, with long apodeme; gonocoxite stout, 1.5X longer than broad; gonostylus with basolateral apophysis, a basomesal impression and a long seta at base and in the middle, with an apical tooth and dense setae ( Fig. 17 ); length 0.22; aedeagal complex membranous and rounded, with apparent lateral parameres, slightly more sclerotized that the body of the aedeagus; medial portion with hyaline projections; distal portion rounded; length 0.12, width 0.10 ( Fig. 19 ). Cercus setose.

Female. Unknown.

Comments. A species with apical darker spot of the wing, that is distinguished from all other New World species by the following combination of characters: antennae dark; hind femur with broad patch of dark pigment covering half of the segment; abdomen with basal pale yellow bands on tergites 2–4, tergites 1 and 5–7 dark brown and wing length 3.84. The specific aedeagus characteristics were not adequately described for the eight named New World species. Papp (2005) commented that the male genitalia characteristics are important in taxonomy.

Distribution. Lygistorrhina borkenti is known only from the National Park “Lagunas de Zempoala”. In this place the altitude varies between 1,250 and 3,450 meters above sea level, and has several types of vegetation, the most representatives being Pinus , Abies and Quercus forests. Specimens were collected with an aerial net at the lake margin.

Etymology. This species is named in honor of Dr. Art Borkent (Research Associate of the Royal British Columbia Museum, American Museum of Natural History and Instituto Nacional de Biodiversidad) for his important contributions to the knowledge of world Ceratopogonidae (Diptera) .

Figures

FIGURES 13 – 19. Lygistorrhina (Probolaeus) borkenti sp. nov., male. 13. Thorax, lateral view (without scale); 14. Wing; 15. Detail of wing apex. 16. Hind leg (femur and tibia, left; tarsomeres I – V, right, lateral view). 17. Genitalia in ventral view (Aedeagal complex removed); 18. Tergite 9 and gonocoxite, dorsal view; 19. Aedeagal complex, ventral view. Scales in millimeters.