Chimerothalassius Shamshev & Grootaert, 2003

Brooks, Scott E. & Cumming, Jeffrey M., 2022, New Australasian Parathalassiinae (Diptera: Dolichopodidae sensu lato), Zootaxa 5188 (6), pp. 521-543 : 524

Chimerothalassius Shamshev & Grootaert

Chimerothalassius Shamshev & Grootaert, 2002: 131 .

Type species: Chimerothalassius ismayi Shamshev & Grootaert, 2002 , by original designation.

Diagnosis. The genus Chimerothalassius is distinguished from other parathalassiine genera by the following characters: head with gena scarcely projected below eye ( Figs 12, 14 , 27 ), mouthparts directed ventrally with fleshy labellum (e.g., Figs 14 , 27 ), palpus elongate and narrow ( Figs 12, 14 ), abruptly capitate apically and narrow basally ( Figs 19 , 27, 28 ), or broadly subtriangular; thorax with prosternum fused to proepisternum forming precoxal bridge, scutellum with 1 pair of strong dorsally directed setae near apex (e.g., Fig. 14 ); legs with fore coxa lacking field of short stout spinose setae on anterior surface, tarsomere 5 of each leg with medial apical projection, although sometimes weakly developed; wing ( Fig. 22 ) with R 1 reaching costa before middle of wing, crossvein bm-m complete or incomplete, cell dm absent without veins M 2 and dm-m, CuA rounded, cell cua convex apically, CuA+CuP absent or vestigial, anal lobe not developed; male terminalia with hypopygium small ( Figs 26, 29, 30 ), right epandrial lamella usually with dorsally directed ventral process ( Figs 17 , 24 , 32 ), cerci symmetrical (or nearly so) and moderately short, hypoproct projected ( Figs 18 , 25 , 33 ); female abdomen with apical segments retracted into segment 5 ( Fig. 21 ), terminalia with syntergite 9+10 undivided and bearing acanthophorous setae and cercus narrowly rounded apically with prominent apical or preapical seta, or syntergite 9+10 divided and bearing acanthophorous spines and cercus pointed apically without apical seta ( Fig. 21 ).

Remarks. Species of Chimerothalassius are known from the Caribbean, Costa Rica, New Zealand ( Figs 3–7 ) ( Brooks & Cumming 2018) and now New Caledonia ( Figs 8–10 ) ( Cumming & Brooks 2019, as “Undescribed genus [ New Caledonia]”). The genus is found on rocky, stony or sandy habitats of coastal beaches ( Figs 4–7 ) and emerged rocks in rivers ( Figs 9, 10 ) ( Shamshev & Grootaert 2002; Brooks & Cumming 2018; Cumming & Brooks 2019).

Figures

FIGURES 12–15. Chimerothalassius ismayi Shamshev & Grootaert and C. marshalli sp. nov. 12. Male of C. ismayi Shamshev & Grootaert from Port Levy, New Zealand (debu00102042), left lateral view. 13. Female of C. ismayi Shamshev & Grootaert from Cable Bay, New Zealand (USNM ENT 00085568), head and foreleg. 14. Male holotype of C. marshalli sp. nov., left lateral view of head and thorax. 15. Male holotype of C. marshalli sp. nov., dorsal view of head and thorax. Abbreviation: plp—palpus.

FIGURES 26–30. Male holotype of Chimerothalassius sinclairi sp. nov. (CNC1155798). 26. Habitus. 27. Head, lateral view. 28. Head, anterior view. 29. Abdomen and terminalia, dorsal view. 30. Abdomen and terminalia, right lateral view. Photos taken prior to removal, dissection and illustration of terminalia. Abbreviation: plp—palpus.

FIGURES 19–22. Chimerothalassius riparius sp. nov. 19. Head of male holotype (CNC1155797), anterior view. 20. Head of male holotype, showing left antenna in medial view. 21. Abdomen of female paratype, lateral view. 22. Right wing of male holotype, dorsal view. Abbreviations: cerc—cercus; M1, M4—medial veins; plp—palpus; R1, R2+3, R 4+5 —radial veins; tg—tergite.

FIGURES 16–18. Hypopygium of Chimerothalassius marshalli sp. nov., holotype (debu00102042). 16. Hypopygium, left lateral view. 17. Hypopygium, right lateral view. 18. Cerci and hypoproct, dorsal view.Abbreviations: cerc—cercus; d sur—dorsal lobe of surstylus; epand—epandrium; hypd—hypandrium; hyprct—hypoproct; (L)—left; pgt lb—postgonite lobe; ph—phallus; (R)—right; v epand proc—ventral epandrial process; v sur—ventral lobe of surstylus.

FIGURES 23–25. Hypopygium of Chimerothalassius riparius sp. nov., holotype (CNC1155797). 23. Hypopygium, left lateral view. 24. Hypopygium, right lateral view. 25. Cerci and hypoproct, dorsal view. Abbreviations: cerc—cercus; d sur—dorsal lobe of surstylus; epand—epandrium; hypd—hypandrium; hyprct—hypoproct; (L)—left; pgt lb—postgonite lobe; ph—phallus; (R)—right; v epand proc—ventral epandrial process; v sur—ventral lobe of surstylus.

FIGURES 31–33. Hypopygium of Chimerothalassius sinclairi sp. nov., holotype (CNC1155798). 31. Hypopygium, left lateral view. 32. Hypopygium, right lateral view. 33. Cerci and hypoproct, dorsal view. Abbreviations: cerc—cercus; d sur—dorsal lobe of surstylus; epand—epandrium; hypd—hypandrium; hyprct—hypoproct; (L)—left; pgt lb—postgonite lobe; ph—phallus; (R)—right; v epand proc—ventral epandrial process; v sur—ventral lobe of surstylus.

FIGURES 1–4. Known geographical distribution and collection localities of Microphorella and Chimerothalassius from Australia and New Zealand. 1. Distribution of M. bungle sp. nov., M. iota Colless and M. viticula sp. nov. 2. Govetts Leap,Australia, type locality of M. viticula sp. nov. (photo by Brad Sinclair). 3. Distribution of C. ismayi Shamshev & Grootaert, C. marshalli sp. nov., Chimerothalassius sp. 1 (female from Takapuna Beach) and “Chimerothalassius” sp. 2 (female from Three Kings Is.). 4. Birdlings Flat, New Zealand, type locality of C. ismayi Shamshev & Grootaert (photo by Rebecca Le Grice).

FIGURES 5–7. Port Levy, New Zealand, type locality of Chimerothalassius marshalli sp. nov. (photos by Morgane Merien).

FIGURES 8–11. Known geographical distribution and collection localities of Chimerothalassius and Eothalassius from New Caledonia. 8. Distribution of C. riparius sp. nov., C. sinclairi sp. nov. and Eothalassius sp. 9–10. Rivère Bleue, type locality of C. riparius sp. nov. and C. sinclairi sp. nov. (photos by Brad Sinclair). 11. Plage de Poé, collection locality of Eothalassius sp. (photo by Brad Sinclair).