Limnellia flavifrontis

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 : 310-312

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

( Figs. 5‒6, 8 , 13‒14 , 30‒37 , 43‒48 )

Diagnosis. This species is distinguished from related congeners by the following combination of characters: Very small shore flies, body length 1.80 mm ( Figs. 5‒6 , 30‒31 ); general coloration shiny brownish black. Head: Head generally yellowish, shiny; mesofrons brownish yellow, without any setae or setulae, except for well-developed pseudopostocellar setae, as long as vertical and fronto-orbital setae ( Figs.13‒14 , 32, 34 ); ocellar triangle and ocellar setae absent; medial and lateral vertical setae present, conspicuous; parafrons and fronto-orbital plate normally developed, yellow; 2 pairs of lateroclinate fronto-orbital setae, anterior very small, posterior well developed; Antenna yellow; arista long, about 4 times length of basal flagellomere, with very small, sparse dorsal rays ( Fig. 33 ). Face shiny yellow, smooth; medial facial area and ventral facial margin with 8 conspicuous setae; 2 vertical rows of setae approximate to parafacials; Gena narrow and brownish yellow, sparsely setulose; gena-to-eye ratio 0.20. Genal seta present, short. Mouth parts yellow.

Thorax: Blackish brown, short, slightly longer than head; pleural sclerites broadly fused and difficult to discern ( Fig. 35 ). Mesonotum bare of microtomentum; rows of acrostichal setae small but evident; prescutellar acrostichal setae present; 2 long dorsocentral setae ( Figs. 30‒31 ). Scutellum very small, with long apical setae; 2 long notopleural seta. Pleurae sparsely setulose. Postsutural supra-alar seta present, three times longer than notopleural seta; anepisternum without setae; 1 small katepisternal setae. Wing brachypterous ( Figs. 8 , 36 ); wing length 0.27 mm; dark brown, with leather-like texture, veins not visible, reduced or absent; covered with setulae and five strong setae at anterior margin. Halter absent ( Fig. 35 ). Legs dark brown, tarsi light brown with apical 2 tarsomeres dark; femora distinctly larger than tibiae; femora and tibiae covered with setulae. Tarsal claws curved and pulvilli normally developed.

Abdomen: Tergites shiny black, bare of microtomentum, with small setulae ( Figs. 30, 31 ). Tergite 1 not visible or absent; tergite 5 larger than previous tergites. Male terminalia ( Figs. 43‒47 ): Epandrium in posterior view ( Fig. 43 ) higher than wide, more or less rectangular with irregularly arched lateral margins and rounded dorsal corners, widely connected dorsally above cercal cavity, ventral margin widely truncate, epandrial setulae uniform in size, confined to dorsal half, in lateral view ( Fig. 44 ) with anterior margin developed at midlength into a narrow, pointed projection, between projection and ventral margin forming a 90 degree curve, cercal opening shallowly concave, tapered toward ventral apex, ventral margin pointed; cercal cavity in posterior view elliptical, rounded dorsally, ventral shallowly pointed ventrally, cerci in posterior view ( Fig. 43 ) semihemispherical, in lateral view ( Fig. 44 ) with anterior margin shallowly curved, posterior margin broadly and slightly tapered, bluntly rounded; surstylar plate in posterior view ( Fig. 43 ) narrowly fused dorsally, otherwise bifurcate with narrow cleft between surstyli, in lateral view ( Fig. 44 ) bar-like, elongate, shallowly curved ventral apex truncate, basal apex tapered, pointed, in ventral view ( Fig. 45 ) U-shaped, gap between arms elongate, narrowly V-shaped, each arm very robustly developed, parallel sided, slightly flared laterally apically, apices truncate; aedeagus in lateral view ( Fig. 47 ) as a C-shaped structure surrounding a bowl-like structure: C-shaped structure with a banana-like process with the apex produced into a short, recurved knob, then an elongate, narrow structure with uneven curvature, portion toward aedeagal base with curvature narrow, hook-like, extension toward fused gonite/hypandrium narrow, parallel sided, curvature shallow, little or no evidence of a keel structure with an apical, short, robust, recurved handle; bowl-like structure in lateral view ( Fig. 47 ) with an apical, short, robust, recurved handle. C-shaped structure in ventral view ( Fig. 46 ) narrow, linear, apex toward aedeagal base irregularly H-like, bifurcate with basal arms short, and apical arms elongate and flared apicolaterally, medial process parallel sided, pointed apically, apex toward fused gonite/ hypandrium truncate; bowl-like structure in ventral view ( Fig. 46 ) rectangular with base truncate, basal lateral margin parallel sided, apical 1/3 tapered to rounded apex; gonite/hypandrium in lateral view ( Fig. 47 ) irregularly Lshaped with anterior arm bent back apically, narrow, as a digitiform process, angle of L almost at a right angle, in ventral view ( Fig. 46 ) fused gonite/hypandrium robust H, with lateral margins shallowly sinuous, anterior half pointed and oriented medially, with a medial hook-like projection that is curved anteriorly, posterior margin of each arm robust, truncate.

Type material. The holotype male of Limnellia flavifrontis is labeled “ VEN: Mérida. Sierra Nevada Natl. Pk., Laguna Negra , 3300 m, 23 May 1998, elfin forest, leaf litter, R. Anderson. [,] HOLOTYPE ♂ / Limnellia flavifrontis Costa, Savaris, Marinoni & Mathis USNM [red]”. The holotype is glued in a paper triangle, is in very good condition, and is deposited in USNM. One male and four females paratypes have the same date and locality label as the holotype .

Type locality. Venezuela. Mérida : Mérida, Sierra Nevada National Park (Laguna Negra; 8 ° 47.1'N; 70 ° 48.4'W; 3300 m).

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

Etymology. The species epithet, flavifrontis , is of Latin derivation and means yellow forehead, referring to the yellowish head of this species.

Remarks. This species is closely related with L. vounitis , exhibiting many of the same modified features, such as the absence of ocelli, ocellar setae and the first abdominal tergite and a compact thorax. It is distinguished from L. vounitis by its larger size, yellowish face, and generally better developed setae. Structures of the male terminalia of this species are very different from L. vounitis and unique among congeners. Initially we thought the C-shaped and very narrow sclerite in lateral view was the phallapodeme. However, comparing these structures to those of L. vounitis and to other congeners with a rudimentary phallapodeme, we now suggest that the more accurate interpretation is that the phallapodeme is completely reduced. We suggest further that the C-shaped and very narrow sclerite in lateral view and the bowl-shaped sclerite together forms the aedeagus. This, however, remains a tentative interpretation. The gonite, as in the previous species, seems to be fused with the hypandrium.

According to the collector, the type series was found in leaf litter, which is another more typical niche for brachypterous species ( Hackman 1964).

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 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.

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.