Lygistorrhina (Probolaeus) alexi 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 : 45-49

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

( Figs. 2–12 )

Type material. Holotype male. Labeled: Mexico, Yucatan, Reserva de Ría Lagartos, Km 10 Carretera Ría Lagartos-Las Coloradas, Peten Tucha, (21º35’46” N, 88º08’47” W), 4–5.IV.1997, Malaise trap, IBS, MMCL, HH, MSP cols. (Specimen dissected and mounted on microscopic slide, deposited in CAIM).

Paratypes: 9 males, 1 female; 3 males with same data than holotype (two specimens deposited in IEXA, one in CAIM); 1 female: Mexico, Yucatan, Municipio Tizimin, 1 km al este de la Estación Biológica “El Cuyo”, Duna Costera (21º30’45” N, 87º40’33” W), Malaise trap, 4.IV.1997, IBS, MMCL, HH, MSP cols. (deposited in CAIM). 6 males: Mexico, Yucatan, Reserva de Celestún, Rancho Loma Bonita, Km 15, Carretera Celestun-Kinchil, Selva baja (20º50’56” N; 90º15’40” W), 25–26.III.1996, Malaise trap, HH, NCC, PRR cols., 3 specimens in CAIM, and 3 specimens deposited in IEXA. (Two specimens dissected and mounted on microscopic slide, and other specimens preserved in 70% ethanol).

Diagnosis. Abdomen of male with basal pale yellow bands on tergites 1–5, last two segments and genitalia dark brown; antennae pale brown; flagellum length 0.74; fore coxa pale yellow, mid and hind coxae reddish brown; hind femur pale yellow with apical 0.40 reddish brown; wing length 2.5; aedeagal complex membranous with distal portion pointed laterally and medially rounded, parameres with pointed tip.

Description. Male. General body coloration reddish brown, 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 1.1, as long as labellum. Antennae ( Fig. 5 ) length 0.88, about 1.5X the head height, with 14 flagellomeres, all uniformly pale brown, each flagellomere longer than wide and with distinct reticulation, and scattered seta-like sensilla; flagellum length 0.74, last flagellomere length 0.073.

Thorax ( Fig. 7 ) reddish brown, scutum slightly convex, sparsely covered with short setae; scutellum with 8 setae; mediotergite bare; supra-alar and notopleural setae 6–8; anterior pronotum and episternum setose; anepisternum bare; katepisternum with ventral margin evenly curved; laterotergite lobulate posteroventrally, and with 21–22 setae; metepisternum with membranous aspect, delimited by a sclerotized line. Fore coxa pale yellow, mid and hind coxae reddish brown, length 0.65, 0.52, and 0.41, respectively; all coxae with sparse setae; fore and midleg femora and tibiae pale yellow; hind femur ( Fig. 8 ) pale yellow, apical 0.40 reddish brown, length 1.48; hind tibia pale yellow with apical 0.25 reddish brown, length 2.07; femur/tibia proportion: 0.7; tarsomeres brown, length I–V: 1.16, 0.51, 0.38, 0.29, 0.23; tibial spurs formula 1:1:2; hind tibial spurs subequal, microtrichose, inner spur 1.5X the length of outer spur; tibial setulae in palisade rows; tarsal claws ( Fig. 9 ) of fore and mid legs curved, with diminutive basal projection, sharply curved with strong arched tip; hind claws length 0.04, slightly curved at apex, with sharp tip; empodia present. Wing ( Figs. 3, 4, 6 ) length 2.5, width 1.10; wing membrane densely covered with microtrichia on whole surface; wing infuscate at apex, darker spot situated at the union of R5 with C, continuing as a faintly infuscation toward vein M1 and reaching the terminal portion of M2; Sc joining C, h not oblique; R1 long and setose, length ca. 0.46X the length of wing; R5 setose except at base; C ending between apices of R5 and M1; Rs absent; only apical third of veins M1 and M2 present, length of M1 0.89, M2 0.79; CuA1 and CuA2 not connected in distal fork, CuA1 length 0.82; 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 white.

Abdomen with basal pale yellow bands on tergites 1–5, more evident on tergites 2–4; last two segments and genitalia dark brown; abdomen length ca. 3.0, length of abdomen in relation to wing length 0.75; sternite 8 rounded at apex. Genitalia ( Fig. 10 ): tergite 9 longer than wide, length 0.24, with the posterior margin rounded and provided with a patch of thickened setae, apodeme long; gonocoxite stout, 1.5X as long as broad; gonostylus with a basolateral apophysis, a basomesal impression, long setae at base, and a tooth and numerous setae at apex, length 0.18. Aedeagal complex membranous, length 0.11, width 0.10, distal portion pointed laterally, medially rounded ( Fig. 11 ); parameres curved, slender with pointed tip. Cercus setose.

Female. Similar to male, but differs as follows: Body length ca. 3.0; flagellum length 0.59 ( Fig. 5 ); wing length 2.43; width 0.92 ( Fig. 2 ); abdomen dark brown; sphermathecae ( Fig. 12 ) oval, slightly different in size, the larger one length 0.070, width 0.058, the smaller length 0.068, width 0.058.

Comments. In the Americas the known species with wing infuscations are Lygistorrhina cerqueirai Lane 1958 from Brazil, Lygistorrhina sp. of Grimaldi and Blagoderov (2001) from Costa Rica, and now L. alexi and L. borkenti from Mexico. All of these species have similar characteristic of the wing maculation, however, in the original description of L. urichi Edwards 1912 , and L. brasiliensis Edwards 1932 , it is mentioned that the wing presents a dark cloud at the tip or it is very faintly indicated. Thompson (1975), Grimaldi & Blagoderov (2001), and Hippa et al. (2005), indicated these species without a dark spot.

Lygistorrhina alexi sp. nov. differs from previously described species by the following characteristics: abdomen with basal pale bands on tergites 1–5 and the last two segments and genitalia dark brown; hind femur with apical 0.40 reddish brown, and male with the paramere slender and pointed apex, although for many species this characteristic they are not described. The wing of the Costa Rican species mentioned by Grimaldi & Blagoderov (2001) is smaller than in L. alexi and does not have an aggregation of thickened setae at the apex of male tergite 9. The differences between L. alexi and L. borkenti are the wing infuscation at apex, color of the hind femur, abdominal segment coloration, and aedeagus morphology. Another similar species is L. urichi , but it has the antennae black, thorax uniformly shining black, fore coxa with the base fuscous and the apex yellowish, halter yellow, and abdomen with apical pale yellow bands.

Distribution. This species is known only from the Biosphere Special Reserves of Ría Lagartos and Ría Celestún, Yucatan, Mexico. All specimens were collected by means of Malaise traps in a typical Yucatan floristic association known as Peten ( Flores & Espejel 1994), which is a differentiated aggregation of trees, shrubs and herbs growing around sites in which the karstic ceiling falls, leaving bodies of subterranean water exposed known as “Cenotes”.

Etymology. This species is named in memory of our friend and colleague, the late Alejandro Pérez García (Alex, as we called him familiarly) (1968–2005), who began to prepare specimens of Mycetophilidae and Bibionidae in the CAIM collection.

Figures

FIGURES 2 – 6. Lygistorrhina (Probolaeus) alexi sp. nov. 2. Female wing; 3. Male wing; 4. Base of wing, male; 5. Antennal flagellum of male (right) and female (left); 6. Detail of wing apex, male. Scales in millimeters.

FIGURES 7 – 12. Lygistorrhina (Probolaeus) alexi sp. nov. 7. Thorax of male, lateral view (without scale); 8. Hind leg, male (femur and tibia, left; tarsomeres I – V, right, lateral view); 9. Male tarsal claws of hind leg (top), mid leg in lateral view (center), and mid leg in ventral view (below); 10. Male terminalia in ventral view (Aedeagal complex removed); 11. Aedeagal complex, ventral view; 12. Female spermathecae. Scales in millimeters.