Limnellia vounitis

Costa, Daniel N. R., Savaris, Marcoandre, Marinoni, Luciane & Mathis, Wayne N., 2016, Two new, brachypterous Limnellia species from the Venezuelan Andes (Diptera: Ephydridae), Zootaxa 4144 (3), pp. 301-315 : 304-310

Limnellia vounitis Costa, Savaris, Marinoni & Mathis n.sp.

( Figs. 1‒4, 7 , 9‒12 , 15‒29 , 38‒42 , 47 )

Diagnosis. This species is distinguished from related congeners by the following combination of characters: Very small shore flies, body length 1.00 mm ( Figs. 1‒4 , 16 , 24 ); general coloration shiny black. Head: ( Figs. 9‒12 , 32 ) Frons generally black, shiny; mesofrons without any setae or setulae, except for very small pseudopostocellar setae; ocellar triangle and ocellar setae absent ( Fig. 27 ); 1 pair of medial vertical setae present, lateral vertical seta absent ( Fig. 25 ); very narrow parafrons and fronto-orbital plate; 2 pairs of very small lateroclinate fronto-orbital setae ( Fig. 26 ). Antenna light brown, pedicel slightly darker; arista long, about 4 times length of basal flagellomere, with very small, sparse dorsal rays ( Fig. 19 ). Face shiny black, with transverse sculpturing; medial facial area and ventral facial margin with small and sparse setae; two vertical rows of setae approximate to parafacials ( Fig. 17 ). Gena narrow, covered with setulae; gena-to-eye ratio 0.25. Genal seta absent or indistinguishable from setulae. Sclerotized mouth parts black, membranous parts brown.

Thorax: Black, short, as long as head; pleural sclerites broadly fused and difficult to discern. Mesonotum bare of microtomentum, with transverse rugosity; 2 very small acrostichal setae; 2 very small dorsocentral setae; prescutellar acrostichal setae present ( Fig. 25 ). Scutellum very small, without setae; one notopleural seta. Pleurae covered with microtomentum. Postsutural supra-alar seta present, same length as notopleural seta. One seta on posterior margin of anepisternum. Wing ( Figs. 7 , 28 ) brachypterous; wing length 0.32 mm; dark brown, with leather-like texture, veins not visible, reduced or absent. Halter very small, near wing base ( Figs. 13 , 18 ). Legs dark brown, except for light brown tarsi; femora distinctly larger than tibiae; femora and tibiae bare of microtomentum, with sparse setulae; tarsi covered with setulae. Tarsal claws curved and pulvilli normally developed ( Fig. 20 ).

Abdomen: Tergites shiny black, bare of microtomentum; with very sparse, small setulae ( Figs. 16, 21 , 24 ). Tergite 1 not visible or absent; tergite 2 larger than subsequent tergites. Male terminalia ( Figs. 29 , 38‒42 ): Epandrium in posterior view ( Figs. 29 , 38 ) wider than high, more or less rectangular with corners rounded, narrowly connected dorsally above cercal cavity, ventral margin shallowly emarginated, setulae uniform in size, evenly distributed except extreme lateral margins, in lateral view ( Fig. 39 ) broadly bar-like, dorsal third tapered to anterodorsal corner, ventral margin truncate; cercal cavity elliptical, cerci in posterior view ( Fig. 38 ) semihemispherical, in lateral view ( Fig. 39 ) narrowly oval, with dorsal and ventral apices rounded; surstylar plate (fused surstyli) in posterior view ( Fig. 38 ) wider than high, octagonal, ventromedially with narrow, deep cleft, in lateral view ( Fig. 39 ) robustly bar-like, elongate, apices truncate, very slightly tapered from base to apex; aedeagus in lateral view ( Fig. 42 ) robustly L-shaped, base wide, basal margin truncate, with a narrow projection from posterior corner, apical arm of L tapered to point, in ventral view ( Fig. 41 ) more or less U-shaped, basal portion deeply developed, width of gap between extended arms subequal to length of base, extended arms shallowly sinuous; phallapodeme generally reduced, in lateral view ( Fig. 42 ) L-shaped with one arm of L much wider than other arm, in ventral view ( Fig. 41 ) shallowly arched, with a medial, short, parallel-sided truncate projection; gonite in lateral view ( Fig. 42 ) irregularly triangular, with narrow, dorsally oriented projection, a shorter anterior, narrow, tapered projection, and a short, wide, truncate posterior projection, in ventral view ( Fig. 41 ) longer than wide, curved basally toward phallapodeme; sternite 5 in lateral view ( Fig. 42 ) irregularly bar-like and one corner projected perpendicular to plane, in ventral view ( Fig. 40 ) wider than long, pentagonal, anterior and lateral margins irregularly quadrate, posterior margin with deep, wide, V-shaped emargination.

Type material. The holotype male of Limnellia vounitis is labeled “ VENEZUELA. Bocon, Ande, La Cristalina, 2500 m., Subparanamo, M.G. Paoletti Feb 1987 ex: rotten wood [,] HOLOTYPE ♂ / Limnellia vounitis Costa, Savaris, Marinoni & Mathis USNM [red]”. The holotype is glued in a paper triangle, is in average condition (some fungi on this specimen; abdomen removed and dissected, parts in an attached microvial), and is deposited in the USNM. The single female paratype ( USNM) has the same date and locality label as the holotype .

Type locality. Venezuela. Trujillo: Bocon, La Cristalina (Andes; 0 9 ° 14.7′N, 70 ° 19.1′W; 2500 m).

Distribution. Neotropical: Venezuela (Trujillo, Fig. 48 ).

Etymology. The species epithet, vounitis , is a Latinized, masculine noun from the modern Greek word, “voynítès” (βουνíτης), and means “dweller on the hills”, referring to the Andes Mountains of Venezuela where the type series was collected.

Remarks. Unlike other brachypterous species of Limnellia , this species has several modifications that are apparently related with its brachyptery, such as the compact thorax and reduced size of the halters. There is also the complete loss of ocelli and ocellar setae, which may also be related with brachyptery and is a synapomorphy that is shared with the other new species being described in this paper.

Some external features of this species, such as the shape of the head, especially the widely arched, vertically elongated, and protrudent face, led us to initially associate this species with the tribe Dagini, perhaps related to the wheeleri species group within the genus Physemops Cresson. Structures of the male terminalia, however, reveal this species to be in the genus Limnellia , which belongs in the tribe Scatellini . Even within Limnellia , this is an anomalous species, given its very compact body, reduced halters, a general reduction of setae and setulae, the conspicuous brachyptery, and the complete loss of ocelli and ocellar setae. The indication of the structure showed in Figs. 40–42 as sternite 5 is also tentative. This sternite is in close proximity to internal structures of the male terminalia and is apparently located within the abdomen. In our specimen, we cannot determine for sure the presence of a sternite 5 in addiction of this structure. Thus we hesitate to suggest that this is another structure since in Limnellia species the hypandrium and gonites are usually fused as a single, united structure.

According to the collector, the type series was found on rotting wood. This niche, combined with the site being at a high elevation, is typical for some flies with reduced wings and it has apparently exerted evolutionary pressure for such. Other aspects of the life history, such as the immature stages, are unknown, although the collection site suggests that this species may be saprophytic.

Figures

FIGURE 48. Distribution map for Limnellia vounitis n. sp. and Limnellia flavifrontis n. sp.

FIGURES 1 ‒ 8, 7. Adult of Limnellia vounitis n. sp. (1 – 2, 7) Male holotype (Venezuela. Trujillo: Bocon, La Cristalina (Andes; 9 ° 14.7 ′ N, 70 ° 19.1 ′ W; 2500 m). (1) Body, dorsal view. (2) Same, lateral view. (3 ‒ 4). Female paratype (3) Body, dorsal view. (4) Same, lateral view. (7) Male right wing. Figures 5 – 6, 8. Adult paratype of Limnellia flavifrontis n. sp. (5 ‒ 6, 8) (Venezuela. Mérida: Mérida, Sierra Nevada National Park (Laguna Negra; 8 ° 47.1 ' N; 70 ° 48.4 ' W; 3300 m )). (5) Male body, dorsal view. (6) Same, lateral view. (8) Male right wing. Scale bar Figs. 1 ‒ 6 = 1.0 mm; Figs. 7 ‒ 8 = 0.1 mm.

FIGURES 9 ‒ 14. Limnellia vounitis n. sp. (9) Male holotype, head, anterior view. (10) Same, oblique view. (11) Female paratype head, anterior view. (12) Same, oblique view. Limnellia flavifrontis n. sp. (13) Male paratype, head, anterior view. (14) Same, oblique view. Scale bar = 0.1 mm.

FIGURES 15 ‒ 23. Limnellia vounitis n. sp., male holotype. (15) Head, anterior view. (16) Body, lateral view. (17) Detail of face, right side, anterior view. (18) Thorax, lateral view. (19) Detail of arista. (20) Midapical tarsomere, (21) Detail of tergite 3, lateral view. (22) Mouth parts, lateral view. (23) Halter, lateral view. Scale bar on figures.

FIGURES 24 ‒ 29. Limnellia vounitis n. sp., male holotype. (24) Body, dorsal view. (25) Thorax, dorsal view. (26) Detail of frons, left side, dorsal view. (27) Pseudopostocellar setae, dorsal view. (28) Left wing, dorsal view. (29) Male Terminalia, ventral view. Scale bar on figures.

FIGURES 38 ‒ 42. Male Terminalia of Limnellia vounitis n. sp. (38) Epandrium, cerci, fused surstylar plate, posterior view. (39) Same, lateral view. (40) Sternite 5, ventral view. (41) Aedeagus, gonite, sternite 5, ventral view. (42) Same, lateral view. Scale bar = 0.1 mm.

FIGURES 43 ‒ 47. Male Terminalia of Limnellia flavifrontis n. sp. (43) Epandrium, cerci, surstylar plate, posterior view. (44) Same, lateral view. (45) Surstylar plate, ventral view. (46) Aedeagus, gonite, hypandrium, ventral view. (47) Same, lateral view. Scale bar = 0.1 mm.

FIGURES 30 ‒ 37. Limnellia flavifrontis n. sp., male paratype. (30) Body, lateral view. (31) Body, dorsal view. (32) Head, anterior view. (33) Detail of arista. (34) Frons, dorsal view. (35) Thorax, lateral view. (36) Right wing, dorsolateral view. (37) Midapical tarsomere. Scale bar on figures.