Litoleptis tico, Grimaldi, 2018

Grimaldi, David A., 2018, First Tropical American Species of the “ Relict ” Genus Litoleptis, and Relationships in Spaniinae (Diptera: Rhagionidae), American Museum Novitates 2018 (3909), pp. 1-20 : 4-11

Litoleptis tico , new species

Figures 2–6

DIAGNOSIS: Small, grayish-brown fly with thorax small, wings large (slightly longer than body) (fig. 2A), venation as in other Litoleptis ; tibial spurs absent, empodium pulvilliform; abdomen slender (figs. 2A; 5A, B), cercus 2-segmented (figs. 5, 6). Best distinguished from other members of the genus by reduced proboscis, the labellum and theca much smaller than palps (figs. 2C, 3A); maxillary palp with one segment, base connected directly to head capsule (fig. 3A); wing with branches of M 1 -M 2 fork curved (vs. virtually straight), crossvein cua-m significantly shorter than r-m (vs. slightly longer) (fig. 4A); spermatheca completely lacking accessory glands (ducts and sacs) (figs. 5C, 6).

DESCRIPTION: Body length 2.7 mm (not including antennae); abdomen length 1.75 mm; thorax length 0.70 mm; head width 0.61 mm; frontal width (between eye margins, at level of antennae) 0.29 mm; wing length 2.8 mm; wing width 1.2 mm. HEAD: Broader than tall; eyes dark, silvery gray, large, occupying entire lateral portion of head (no cheek exposed laterally); no differentiation of facets (only female known), eye completely bare; inner margins on frons nearly parallel, margins bordering face slightly diverging ventrad, no emargination. Frons dark brown, slightly raised above level of eyes; shiny, with scattered, fine, long setulae (lengths ca. 2.5× diameter of facet). Lower part of frons and area between antennal bases with faint, vertical median furrow. Ocelli light, large, of equal size; lying on shallow, velvety-black tubercle; ocellar triangle/tubercle slightly recessed into vertex of head. Occiput concave; dorsal portion with dark, fine, stiff setulae pointing upward. Antennal bases widely separated, by distance slightly greater than diameter of scape; scape ringlike, hidden frontally by pedicel, encircled by larger, exposed membranous area; pedicel short, slightly conical, without apical ring of setulae; basal flagellar article long, tapered, heavily setulose; apex lacking style, with pair of stiff, needlelike setae at apex, length ca. 0.4× that of basal flagellar article. Face broad, slightly broader than frons, dark brown; clypeus slightly swollen, paraclypeal sulci faintly impressed. Palp one-segmented; base slender, ca. 0.3× width of apex, which is swollen; base with longer setulae; palp connected directly to head capsule (membranous articulation visible frontally). Proboscis very small, length approximately equal to that of basal palpomere, labellum very small, appears nonfunctional, with 5–6 fine setae per lobe; labrum tiny, whitish, membranous. Anterior tentorial pit deep, well defined; located just above base of palp.

THORAX: Short, broad, scutum slightly wider than long. Scutum shiny, dark brown, with two large glabrous/shiny patches laterally, two smaller paramedian glabrous patches; other portions of scutum with dense, dark microtrichia forming trident shape; scutellum entirely matte. Stiff, fine, dark setae on paramedian stripes, and laterally on notopleural and supraalar areas. Transverse suture barely developed. Area between notopleura and pleura, and surrounding wing base, whitish. Pleura entirely glabrous, devoid of setae, setulae, microtrichia; sclerite proportions and sizes shown in figure 2B. Mesothoracic spiracle a large vertical slit. Legs slen- der but relatively short; coxal lengths cx1> cx2> cx3, bases of cx1 by posterior portion of head; coxae with 5–6 setulae on each. Legs with fine, scattered dark setulae; lengths slightly greater than podite width; apices of all podomeres except femora are dark. Femoral lengths f3> f2> f1; profemur shorter than protibia; meso- and metafemur about same length as tibiae; hind femur slightly swollen apically. All tibiae lack apical spurs. Tarsus shorter than respective tibia; basitarsomere slightly shorter than distal tarsomeres combined (2–5), distal tarsomere widest. Claws, pulvilli well developed; empodium pulvilliform, slightly larger than pulvilli.

WINGS: Large, slightly longer than body, uniformly dusky, with dense microtrichia (fig. 4B). Venation very similar to the other two New World species, with differences as noted: like alaskensis with R 3 slightly curved costad (vs. straight, as in chilensis ); like chilensis with fork of R 4+5 only slightly divergent, lengths of branches nearly equal (R 4 /R 5 0.82 in tico , 0.84 in chilensis , 0.75 in alaskensis ). Unique to tico are branches of M 1 -M 2 fork curved (vs. virtually straight); crossvein cua-m very short (ca. 0.5× length of r-m crossvein, vs. slightly longer than r-m in chilensis , alaskensis , and species from Japan; fig. 4C, D). Halter large, length approximately equal to width of scutum, length of knob and stalk approximately equal; knob very swollen, with dense covering of microtrichia (fig. 2D).

ABDOMEN: Slender, with very broad attachment to thorax (essentially no constriction), only slightly tapered in width apicad. Tergites lightly sclerotized, light brown, with subtle ridge running down middle of abdomen (fig. 5A); tergite 1 approximately 0.5× length of other tergites (2–7). Tergites with microtrichia plus scattered, very fine setulae. Pleural membrane well exposed, spiracles in membrane at level of segment divisions. Sternites approximately same size as tergites (fig. 5A, B), with similar vestiture but lighter and less sclerotized; lateral margins of sternite 8 with apical third tapered, posterior margin slightly concave. Cercus short, two-segmented, apical cercomere slightly conical (figs. 5C, 6).

ETYMOLOGY: As a noun in apposition, taken directly from “ticos,” a familiar and affectionate name that Costa Ricans give to each other, in reference to their tendency to add the diminutive “tico” to the end of words.

TYPE: Holotype, female: COSTA RICA: San José, Zurquí de Moravia , 1600 m., VII/92, P. Hanson, Malaise trap. Latitude 10.047 N, longitude 84.008 W. In AMNH. The specimen is in excellent condition, originally critical-point dried from alcohol; originally fully intact (except for loss of setae on one antennal tip). The right wing and terminalia were removed for temporary slide mounting (using glycerin-jelly) and photography; they are stored in a genitalia vial in glycerin on the pin with the type.

Figures

FIG. 2. Litoleptis tico, new species, holotype. A. Dorsal habitus of intact specimen, prior to dissection of terminalia and removal of wing. B. Anterior half of body, lateral view. C. Frontal view of head. D. Dorsal view of head and thorax.

FIG. 3. Litoleptis tico, holotype. A. Drawing of facial region. B. Detail of antennal tip (based on scanning electron micrographs of uncoated holotype).

FIG. 4. Wing of Litoleptis species. A, B. L. tico, holotype. A. Entire wing. The dark pseudostigma is only preservational, due to air trapped in this swollen area. B. Base of wing. C. L. kiiensis Imada and Kato. D. L. japonica Imada and Kato.

FIG. 5. Terminalia of L. tico, holotype. A, B: Abdominal apex of intact specimen, prior to dissection. A. Dorsal. B. Ventral. C. Macerated dissection. Spermathecae are collapsed.

FIG. 6. Drawing of L. tico terminalia (cf. fig. 5C). Spermathecae have been reconstructed to their original shape.