Chimerothalassius sinclairi, Brooks & Cumming, 2022

Brooks, Scott E. & Cumming, Jeffrey M., 2022, New Australasian Parathalassiinae (Diptera: Dolichopodidae sensu lato), Zootaxa 5188 (6), pp. 521-543 : 530-533

Chimerothalassius sinclairi sp. nov.

( Figs 8–10 , 26–33 )

urn:lsid:zoobank.org:act:4402E850-080F-4802-8725-15A2D694503E

Type material. HOLOTYPE ♂ labelled: “ NEW CALEDONIA: Parc / Rivève [sic] Bleue; R. Bleue / nr. refuge [ca 22°05ʹ50ʺS 166°38ʹ17ʺE], 20–21.vii./ 1995; B.J. Sinclair / ex. yellow pans”; “ CNC/ 1155798 ”; “ HOLOTYPE / Chimerothalassius sinclairi / Brooks & Cumming [red label]” ( MNHN).

Diagnosis. Known only from a single male, C. sinclairi sp. nov. is distinguished from the other known Australasian species of the genus by its white capitate palpus ( Figs 27, 28 ), and several hypopygial features ( Figs 29–33 ) including: left ventral epandrial process with narrowed beak-like tip; left ventral surstylus short with short seta; right epandrial lamella with large elongate seta on posterior margin; right ventral epandrial process sinuous; phallus sinuous and narrow; cercus with long setae; hypoproct simple and broad.

Description. Male ( Figs 26–33 ): Body length 1.20 mm, wing length approximately 1 mm. Head ( Figs 27, 28 ): Silvery grey pruinose with bluish reflections; broader than thorax in dorsal view; round in lateral view (about as broad as high); broader than high in anterior view; larger setae black. Ocellar triangle conspicuous. Occiput weakly concave on upper median part. Eyes covered with short ommatrichia; medial edge of eye with distinct emargination adjacent to antenna; ommatidia progressively smaller anterodorsally. Frons 3X broader than high, widening above. Face narrow, with eyes nearly contiguous. Face and clypeus concolorous with rest of head. Clypeus not separated from face, small and triangular, not produced. Setae of head well differentiated: 1 pair of weakly reclinate frontoorbitals close to base of antennae; 1 pair of small anterior ocellars; 1 pair of small posterior ocellars; 1 pair of inclinate inner verticals (sometimes referred to as postocellars); 2 pairs of lateroclinate outer verticals; postoculars short fine and pale, upper few setae uniserial, lower setae scattered and longer around oral cavity. Antenna entirely pale brown, inserted slightly above middle of head in profile; scape short, funnel-shaped; pedicel slightly longer than scape, spheroidal with subapical circlet of setulae; postpedicel 2.7X longer than wide, bulb-shaped with basal 1/3 round and distal 2/3 narrow, clothed in fine setulae, longer on narrow distal part; arista-like stylus 1.6X length of postpedicel, with minute hairs. Palpus bright white, narrow basally, abruptly capitate apically. Proboscis pale brown, short. Gena narrow. Thorax: Brown with light silver-grey pruinosity, with green and bronze reflections especially dorsally, setae black. Mesoscutum weakly arched, prescutellar depression present. Proepisternum with tiny upper and tiny lower seta. Postpronotal lobe with 1 minute seta. Mesonotum longer than wide. Acrostichal setae short, uniserial and irregular; other thoracic setae mostly short and weak, each side of mesonotum with: approximately 7 dorsocentrals (anterior setae similar to acrostichals, posterior seta stronger), apparently 2 short presutural supra-alars (posthumerals), postsutural supra-alar broken or absent, 2 strong notopleurals, postalar apparently broken. Scutellum broadly subtriangular with 1 long, strong, dorsally projected seta per side. Mesopleuron bare. Halter whitish. Legs ( Fig. 26 ): Mostly pale brown except, fore coxa pale yellow, femora partially to mostly pale yellow ventrally; with mostly short pale setae; tarsomeres 1–4 of all legs progressively shorter apically with tarsomere 5 slightly longer than 4; tarsomere 5 of all legs with dorsomedial finger-like process; tarsal claws small, pulvilli and empodium normally developed on all legs. Foreleg: Coxa with fine setae on anterior surface, several basal setae longer, apical margin with setae longer; femur slightly longer than tibia and somewhat enlarged, with series of several small erect setae basally and series of stronger posteroventral setae along distal half; tarsus subequal in length to tibia; tarsomere 1 subequal to combined length of tarsomeres 2–4. Midleg: Coxa obscured from view; femur, tibia and tarsus subequal in length; tarsomere 1 subequal to combined length of tarsomeres 2–4. Hindleg: Coxa with 1 visible pale seta on lateral surface; femur slightly longer than tibia; tarsus subequal in length to tibia; tarsomere 1 subequal to combined length of tarsomeres 2–3. Wing ( Fig. 26 ): Similar to C. riparius sp. nov. (see Fig. 22 ), except as follows: Extreme anterior base of costa bare. Base of wing proximal to tip of cell cua quite narrow. Calypter without setae. Abdomen ( Figs 29, 30 ): Pale brown with small brownish setae (weaker on sternites); sternite 6 and segment 7 bare. Segments 5–7 narrowed and laterally compressed to form cavity on right side for hypopygium. Sternite 5 lacking pregenitalic process. Sternite 8 ovoid, with short setae; tergite 8 indistinct. Hypopygium ( Figs 29–33 ): Concolorous with pregenitalic abdominal sclerites; lateroflexed to right; inverted with posterior end directed anteriorly; small and compact, about 1/4 length of abdomen; asymmetrical; foramen not formed. Epandrium divided into left and right lamellae. Left epandrial lamella ( Fig. 31 ) largely overlapping left side of hypandrium, with broadly projecting and rounded anterior margin, posterior margin trifurcate, ventrally fused with hypandrium but margin distinct; ventral epandrial process apparently not articulated at base, long and slender, bent ventrally, with narrowed beak-like tip. Left surstylus bilobed, dorsal and ventral lobes separated by shallow U-shaped cleft through which left postgonite lobe protrudes. Dorsal lobe of left surstylus broadened mid-ventrally with short apical seta, long preapical dorsal seta and short dorsal seta, lacking prensiseta. Ventral lobe of left surstylus short with short preapical seta. Right epandrial lamella ( Fig. 32 ) elongate and subtriangular, partially overlapping right side of hypandrium, ventrally fused with hypandrium but margin distinct, longer than hypandrium, with large elongate seta near middle of posterior margin; ventral epandrial process present, sinuous and projecting dorsally, hidden behind right epandrial lamella. Right surstylus bilobed, dorsal and ventral lobes separated by U-shaped cleft through which right postgonite lobe protrudes. Dorsal lobe of right surstylus short with short apical seta, long preapical dorsal seta and short dorsal seta, lacking prensiseta. Ventral lobe of right surstylus elongate and broadly bifurcate apically, with 1 ventral seta near middle and 1 small medial seta near bifurcation. Hypandrium relatively small and narrowing anteriorly, shorter than epandrium in lateral view. Left postgonite lobe large and long, broad basally, gradually tapered to narrow apex ( Fig. 31 ). Right postgonite lobe shorter than left lobe, with broad rounded apex ( Fig. 32 ). Phallus tubular, sinuous and narrow, bent upwards. Ejaculatory apodeme apparently keel-like. Hypoproct simple and broad in dorsal view ( Fig. 33 ) left and right sides symmetrical. Cercus subrectangular in dorsal view ( Fig. 33 ), with 3 long setae, left and right cercus symmetrical.

Female. Unknown.

Distribution. This new species is known only from the type locality along Rivère Bleue in the Yaté Commune of the South Province of New Caledonia ( Figs 8–10 ).

Etymology. This species is named in honour of our colleague, Dr. Bradley J. Sinclair who collected the unique holotype along the margin of Rivère Bleue ( Figs 9, 10 ) using yellow pan traps. Brad’s collecting efforts in Australia and New Caledonia also produced the only known specimens of Chimerothalassius riparius sp. nov. and Microphorella viticula sp. nov.

Remarks. The holotype of C. sinclairi sp. nov. was collected together with the type series of C. riparius sp. nov. in yellow pan traps placed along the margin of Rivère Bleue.

Figures

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).

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 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 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.