Neothalassius

Brooks, Scott E. & Cumming, Jeffrey M., 2016, Neothalassius, a new genus of Parathalassiinae (Diptera: Dolichopodidae s. lat.) from the Pacific coast of South America, Zootaxa 4066 (3), pp. 311-322 : 313-314

Key to species of Neothalassius (males)

1 Antennal arista-like stylus longer than postpedicel ( Figs 9, 10 ); head higher than broad in anterior view ( Fig. 9 ) with parafacial plate and gena strongly produced, ovoid in lateral view ( Fig. 10 ) with postgena moderately developed bearing short setae; face broad; palpus exposed and mostly visible; R1 reaching costa before middle of wing, well before termination point of M4 (Fig. 13); coxa of foreleg with spine-like setae on lower anterior surface only, trochanter and base of fore femur without similar spine-like setae; first tarsomere of fore tarsus with slight ventromedial excavation; abdominal sternite 1 with short, rounded medial process on anterior margin; male terminalia with sternite 8 lacking cleft along posterior margin, sparsely covered with short unmodified setae.................................................................... N. triton sp. nov.

- Antennal arista-like stylus shorter than postpedicel ( Figs 11, 12 ); head shorter than broad in anterior view ( Fig. 11 ) with parafacial plate and gena moderately produced, rounded in lateral view ( Figs 5 , 12 ) with postgena broad bearing long setae below; face narrow, palpus largely concealed; R1 reaching costa near middle of wing, almost in line with termination point of M4; coxa of foreleg with spine-like setae on entire anterior surface ( Fig. 5 ), trochanter and base of fore femur with similar spine-like setae; first tarsomere of fore tarsus with large basiventral swelling; abdominal sternite 1 with long, spine-like process on anterior margin projecting anteriorly between hind coxae ( Fig. 7 ); male terminalia with sternite 8 cleft along posterior margin, bearing eyelash-like row of long setae on each side of cleft ( Fig. 8 )............................... N. villosus sp. nov.

Figures

FIGURES 9 – 12. Heads of males. 9. Neothalassius triton sp. nov., anterior view. 10. Neothalassius triton sp. nov., lateral view. 11. Neothalassius villosus sp. nov., anterior view. 12. Neothalassius villosus sp. nov., lateral view. Abbreviations: ar stylarista-like stylus; gn—gena; lbl—labellum; pafc—parafacial; plp—palpus; pped—postpedicel.

FIGURES 5 – 8. Neothalassius villosus sp. nov., male habitus and abdomen. 5. Lateral habitus of holotype ♂ (antennal aristalike stylus broken off). 6. Dorsal habitus of holotype ♂ (antennal arista-like stylus broken off). 7. Male abdominal sternites of paratype ♂. 8. Postabdomen of holotype ♂, dorsal view. Abbreviations: proc—process; st—sternite; tg—tergite.