Chimerothalassius, Shamshev & Grootaert, 2003

Brooks, Scott E. & Cumming, Jeffrey M., 2018, New species of Chimerothalassius Shamshev & Grootaert (Diptera: Dolichopodidae: Parathalassiinae) from the West Indies and Costa Rica, Zootaxa 4387 (3), pp. 511-523 : 517-519

Chimerothalassius sp.

(Figs 10, 17, 18, 19, 22)

Material Examined. COSTA RICA: Herradura , 21.X.1993, light trap (UV flourescent on white sheet) at edge of ocean beach, A. Borkent, CD1628 (2♀, CNC) ; Caldera , 24.viii.1993, swept rocks amidst sand strip along ocean, A. Borkent, CD1548 (1♀, CNC) .

Diagnosis. Minute (wing length 1.0– 1.1 mm); head, thorax and abdominal tergites with dense grey pruinosity mostly covering brownish ground colour; abdominal sternites mostly pale and concolourous with adjacent membrane, sternite 6 with weak grey pruinosity; legs mostly pale or weakly infuscate, tarsi infuscate apically; setae of body and legs white; head with lower 5–7 postocular setae long; palpus large, broadly subtriangular, lacking FIGURES 7–10. Wings (dorsal surface). 7. Chimerothalassius runyoni sp. nov., specimen of unknown sex from Rodney’s Rock, Dominica. 8. Same, female paratype from Woodlands Beach , Montserrat . 9. Same, male paratype from Woodlands Beach , Montserrat . 10. Chimerothalassius sp., female from Herradura, Costa Rica. Abbreviations: C—costa; cua—anterior cubital (=anal) cell; h—humeral crossvein; M1, M4—medial veins; R1, R2+3, R4+5—radial veins.

ventral bristles; fore coxa with prominent setae on anterior surface, lower 2–3 setae long; fore femur with series of 3–4 long setae ventrally; wing about 2X longer than wide (Fig 10); costal section between R2+3–R4+5 shorter than R4+5–M1 section; female terminalia with tergite 8 medially divided, narrowly fused with sternite 8 anterolaterally; tergite 10 divided medially with three acanthophorite setae on each broadly-tipped hemitergite; cercus with long apical seta and long lateral seta ( Fig. 18 ); spermathecal duct an unsclerotized tube with broad ridged sperm pump in basal part and conical terminal expansion giving rise to sac-like spermatheca ( Fig. 17 ). Male is unknown.

Distribution. This undescribed species is currently known only from two localities on the Pacific coast of Costa Rica ( Figs 19 , 22 ).

Remarks. Like the other known species of Chimerothalassius , this species appears to be associated with beach rocks, however the two specimens from Herradura were taken at a UV light trap placed near the shoreline.

Figures

FIGURE 19. Known distribution of New World Chimerothalassius species.

FIGURES 17–18. Female terminalia of Chimerothalassius sp. from Costa Rica. 17. Spermatheca. 18. Dorsal view. Abbreviations: cerc—cercus; tg—tergite.

FIGURES 20–22. Detailed distribution maps of New World Chimerothalassius species. 20. Collection locality of Chimerothalassius runyoni sp. nov. on Montserrat. 21. Collection localities of Chimerothalassius runyoni sp. nov. on Dominica. 22. Collection localities of Chimerothalassius sp. on west coast of Costa Rica. Map data: Google, DigitalGlobe. Scale bar = 10 km.