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

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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 View FIGURES 17–18 ); 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 View FIGURES 17–18 ). Male is unknown.

Distribution. This undescribed species is currently known only from two localities on the Pacific coast of Costa Rica ( Figs 19 View FIGURE 19 , 22 View FIGURES 20–22 ).

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.


Canadian National Collection of Insects, Arachnids, and Nematodes