Curtonotum irksum Lindsay, 2019

Lindsay, Kate G., Klymko, John & Marshall, Stephen A., 2019, Revision of the Central American and Mexican species of the Curtonotum murinum species complex (Diptera: Curtonotidae), Zootaxa 4651 (3), pp. 531-554 : 543-546

Curtonotum irksum Lindsay , sp. nov.

Figures 8 , 9 , 24–31

Differential diagnosis. Distinguished from congeners by the inner lobe of the surstylus which is 6–7 times as long as wide and wedge shaped and the distal distiphallus, which has an asymmetrical, stout, leaf-like lobe that is sclerotized on the left and membranous with microtrichia on the right. The upper projection of the distiphallus is curled and slightly wider apically; the lower projection is short, thin, sclerotized and slightly reflexed ( Fig. 31 ). Tergite 3 has a posterior band covering 1/6 to 1/4 the tergal length ( Fig. 27 ). Females are here treated as indistinguishable.

Description. Male: Overall length (excluding wings): 4–7.2 mm.

Head: Vibrissa subequal to subvibrissae. Parafacial thin, gena approximately 1/4 width of postpedicel. Post- pedicel 1–1.5 times length of pedicel. Arista with 6–8 dorsal branches, 4–5 ventral branches.

Thorax: Scutum with faint grey dorsal markings. Postpronotal lobe with 3–4 setae (1 long, the remainder shorter and subequal), sometimes with several poorly defined, scattered setulae ventrally. Line of setulae above fore coxa black.

Legs: Orange to beige. Hind femur with wide, dark brown preapical band.

Wing: Membrane light grey-brown, with indistinct infuscation around crossvein dm–m and at anterior margin.

Abdomen: Tergite 2 with 2 posterolateral markings covering 1/3 to 2/3 tergal length. Tergites 3–5 with a distinct median vitta and mottled, lateral triangles. Band on posterior margin of tergites 3–5 adjoining medial and lateral markings moderate, covering 1/6 to 1/4 of tergite 3.

Male terminalia: Cercus somewhat elongate, same length as epandrium at widest point. Surstylus modified into 2 lobes: inner lobe black, wider distally, 6–7 times as long as wide, approximately same length as cercus; outer lobe 5–6 times as wide as inner. Postgonite harpoon shaped. Hypandrium with blunt dorsobasal projection. Phallapodeme thin, shorter than epandrium. Distiphallus with distal asymmetrical, stout, leaf-like lobe sclerotized on left and membranous with microtrichia on right. Upper projection of distal lobe recurved with wider tip, lower projection thin, sclerotized and slightly reflexed.

Female: Unknown.

Etymology. Includes the English root “irk”, referring to the irritating nature of this species when the writers attempted (and failed) to diagnose the females.

Comments. Four females matching the general external diagnosis of C. irksum sp. nov. from Costa Rica were dissected, but no distinct terminalia characters could be identified to diagnose females of this species. This species appears to be relatively common and can be locally abundant. Large numbers were noted on foliage in a patch of low vegetation in an opening in lowland forest near Dominical, Costa Rica.

Type material. Holotype: ♂: COSTA RICA. Puntarenas: Estacion Sirena , 1–100 m, [8°28’ 48.756”N, 83°35’21.98”W], III.1996, G. Fonseca, L_S_ 270500 _508300#7243 ( MNCR) . Paratypes: COSTA RICA. Guanacaste: 2♂, 14 km S. Canas, 17–24.I.1991, F.D. Parker ; ♂, same except: 1–4.IX.1989; ♂, same except: 23–28.II.1990; ♂, same except: 1–7.IV.1990; ♂, same except: 1–8.III.1990; ♂, same except: 4–6.V.1989; ♂, same except: 21– 25.I.1989; 2♂, same except: 23–31.III.1990; 4♂, same except: 16–22.II.1990; ♂, same except: 1–7.IV.1990; 4♂, same except: 15–22.I.1990; ♂, same except: 8–15.IV.1991; ♂, same except: 16–23.IV.1991; ♂, same except: 17– 24.I.1991; ♂, same except: 22–31.III.1990 (All EMUS) ; 3♂, R.V.S. Bosque Diria, Estacion Diria , 160 m, 9.II.2003, D. Bricerio, L_N_239900_362700#72758 (all MNCR) . Limon: 2♂, R.V.S. Gandoca–Manzanilla, Punat Mona , 0–3 m, 6.XI.2001, B. Hernandez, L_S_395700_614500#69061 ; ♂, Talamanca, P.N. Cahuita, Puerto Vargas , 0 m, 26.V.2000, E. Rojas, L_S_191574_666430#57060 ( MNCR) . Puntarenas: ♂, Estacion San Miguel, Punta Coqui- tos, 1 m, 22.VII.1997, F. Alvarado, L_N_17320_412100#47842 ; ♂, P.N. Corcovado, Sector Sirena, sendero Pavo. , 10 m, 29.VIII.2002, K. Caballero, L_S_ 270500 _508300#71199 .; 7♂, P.N. Corcovado, Estacion La Leona , 0–5 m, 23.VI.2002, K. Caballero, L_S_267250_519575#70150 ; 3♂, P.N. Corcovado, Sector La Leona, sendero A Cerro Puma , 100–300 m, 26.VI.2003, M. Moraga, L_S_267700_518900#74498 ; ♂, P.N. Corcovado, Sector La Leona, sendero Cerro Puma , 100–300 m, 2.VII.2003, M. Moraga, L_S_267700_518900#744699 ; ♂, P.N. Corcovado, De- sembocadura de Rio Madrigal , 5 m, 18.III.2003, K. Caballero, L_S_267200_519500#73590 ; ♂, Garabito, R.B. Carara, E, Queb Bonita, S. Queb. Bonita , 90 m, 13.II.2000, B. Hernandez, L_N_194844_470315#57132 ; 3♂, Es- tacion Sirena, P.N. Corcovado , 0–100 m, IV.1992, G. Rodriguez, L_S_ 270500 _508300 ; ♂, Estacion Sirena, P.N. Corcovado , 20 m, 22.III.1995, L. Angula, L_N_269504_508675#4689 ; 3♂, Estacion Sirena, P.N. Corcovado , 0– 100 m, XI.1993, G. Fonseca, L_S_ 270500 _508300#2490 ; ♂, Estacion Sirena, P.N. Corcovado , 1–100 m, X.1993, G. Fonseca, L_S_ 270500 _508300#2380 ; ♂, Estacion Sirena, P.N. Corcovado , 1–100 m, X.1993, G. Fonseca, L_ S_ 270500 _508300#7243 ; ♂, Estacion San Miguel , 1 m, 22.V.1997, F. Alvarado, L_N_174100_411600#46875 ; ♂, Estacion Santa Rose, 300 m, 16.II.1996, S. Marshall, Borde del Rio , L_N_313000_359800#6920 (all MNCR) ; ♂, Parque Nacional Corcovado, Estacion Sirena , 8°28–31’N, 83°36’W, 18.III.1981, H.A. Hespenheide ( CASC) ; ♂, Hacienda Baru de Dominical Reserve , 2 km N, 22–25.II.2008, S.A. Marshall, debu00294597 ; ♂, Hacienda Baru de Dominical Reserve , 2 km N, 22–25.II.2008, S.A. Marshall, debu00294593 ; ♂, Natl. Pk. San Pedrillo , 1–50 m, 8°37’15’N, 83°44’6’W, on Heliconia leaves, 14.VIII.2001, S.A. Marshall, debu00203032 ; ♂, Osa Pen, Corco- vado, NP, San Pedrillo , 08°37.5’N, 83°44.1’W, 14.VIII.2001, K.N. Barber, forest ( DEBU) . GUATEMALA. San Marcos: ♂, Ayutla , IV.1913, J.M. Aldrich ( USNM) . MEXICO. Chiapas: ♂, Agua Cero , 18.V.1985, A. Freidberg ( USNM) . Honduras : ♂, Roatan Island , 27.II.1979, G.E. Bohart ( EMUS) ; 2♂, Puerto Castillo , 2.IV.1926, R.H. Painter ( USNM) . Jalisco: ♂, Puerto Vallarta , 5–10.XII.1985, G.E. Bohart ; ♂, Roatan W., 1.I.1980, G.E. Bohart ; ♂, Chamela ( Estacion Biológica ), 4.XI.1987, T. Griswold ( EMUS) . PANAMA. Colón: 2♂, Devil’s Beach , 5 km W. Ft. Sherman, 9–10. VIII.1975, E.M. Fisher . Panamá Oeste : ♂, La Chorrera , 20.XII.1944, K.E. Frick ( CASC) . VENEZUELA. Carabobo: ♂, Embalse de Guataparo , W Valencia, 13.IV.1972, L. Knuston ( USNM) .

Other material examined. COSTA RICA. Guanacaste: ♀, Sector Santa Maria, 6 km S. del Volcan Santa Ma- ria, 750–790 m, 10–15.III.1996, F.A. Quesada, D. Briceno, A. Masis, L_N_304800_393700#7335 ; ♀, Pto Jimenez, 0 m, 23.III.1995, L. Angulo, L_N_ 270900 _508100#4687; 2♀, R.V.S. Bosque Diria, Estacion Diria, 100–200 m, 9.II.2003, W. Porras, L_N_239550_361650#73266; ♀, R.V.S. Bosque Diria, Estacion Diria, 100–200 m, 9.II.2003, W. Porras, L_N_239550_361650#73266. Limon: ♀, R.V.S. Guandoca-Manzanillo, Sector Gandoca, Playa Guand- oca, 0–3 m , 31.X.2001, B. Hernandez, L_S_393250_616550#69043. Puntarenas: ♂, Hacienda Baru de Dominical Reserve , 2 km N , 22–25.II.2008, S.A. Marshall, debu00294611; ♂, Hacienda Baru de Dominical Reserve , 2 km N , 22–25.II.2008, S.A. Marshall, debu00294584; 6♀, P.N. Corcovado, Estacion La Leona , 0–5 m , 23.VI.2002, K. Ca- ballero, L_S_267250_519575#70150; 2♀, P.N. Corcovado, Sector Sirena, sendero Corcovado, 70 m, 28.XI.2002, K. Caballero, L_S_ 270500 _508300#72438; 3♀, Golfito, P.N. Corcovado, Estacion Sirena, sendero Corcovado, 10 m, 15.XI.2001, K. Caballero, L_S_ 270500 _508310#66627; ♀, Golfito, P.N. Corcovado, Estacion Sirena, sen- dero Privado, 10 m, 3.VIII.2000, K. Caballero, L_S_508300_ 270500 #58270; ♀, Golfito, P.N. Corcovado, Sector Sirena, sendero Ollas, 70 m, 30.XI.2002, K. Caballero, L_S_ 270500 _508300#72440; ♀, Golfito, P.N. Corcovado, Estacion Sirena, 10 m, 17.IX.2000, K. Caballero, L_S_ 270500 _508310#66628; ♀, Golfito, P.N. Corcovado, Esta- cion Sirena, 10 m, 17.IX.2000, K. Caballero, L_S_508300_ 270500 #58269; ♀, Golfito, P.N. Corcovado, Sector La Leona , Cerro Puma, 100–300 m , 2.VII.2003, M. Moraga, L_S_267700_518900#74699; ♀, P.N. Corcovado, Sector La Leona , Cerro Puma, 100–300 m , 10.VII.2003, M. Moraga, L_S_267700_518900#74484; ♀, Cobano, R.N.A Cabo Blanco, Estacion San Miguel, 200 m, 18.III.2001, Y. Cardenas, L_N_413200_174850#61739; ♀, Estacion Sirena, 1–100 m, 5–23.IV.1995, A. Picado , L_N _ 270500 _507900#4552; 2♀, Estacion Sirena, 1–100 m, III.1996, G. Fonseca, L_N_ 270500 _508300#7243; ♀, Estacion Sirena, 1–100 m, 22.V.1997, F. Alvorado, L_N_174100_ 411600#46875; ♀, Estacion Sirena, 1–100 m, II.1995, G. Fonseca, L_N_ 270500 _508300#4369; ♀, Estacion Sirena Rio Claro, 20 m, 22.III.1995, L. Angulo, L_N_269504_508675#4689; ♀, Estacion San Miguel, senderos Maven, 100 m, 18.II.1997, F. Alvarado , L_N_174400_411750#45454; ♀, P.N. Corcovado, 1–100 m , III.1994, G. Fonseca, L_S_ 270500 _508300#2769; ♀, Estacion Sirena, Playa Sirena, 1–100 m, 20–17.III.1995, A.M. Maroto , L_S _ 270500 _508300#5430; ♀, Estacion Sirena, 1–100 m, II.1995, G. Fonseca, L_S_ 270500 _508300#4369; 2♀, Estacion Sirena, 1–100 m, 5–23.IV.1995, A. Picado , L_N _ 270500 _507900#4552; 3♀, Punta Catedral, P.N. Man- uel Antonio, Quepos, VII.1992, G. Varela, L_S_870900, 448800; ♀, R.N. Cabo Blanco, Estacion San Miguel, VIII.1993, M. Ramirez. L_S_173174_411412#2343; ♀, Osa Peninsula, Corcovado National Park , 13–23.III.1978, D.H. Janzen (all MNCR). GUATEMALA. San Marcos: ♂, Ayutla , IV.1913, J.M. Aldrich. PANAMA. Coclé: ♀, El Valle , I.1947, N.H.L. Krauss ( USNM). Panamá: ♀, Ft. Kobbe , 9.VIII.1958, W.J. Hanson (all EMUS) .

Figures

FIGURE 8. Head of Curtonotum irksum sp. nov., anterior view.

FIGURE 9. Living example of Curtonotum irksum sp. nov. from Hacienda Baru, near Dominical, Costa Rica.

FIGURES 24–27. External characters of Curtonotum irksum sp.nov.. 24. Habitus, lateral view ♂. 25. Head, anterior view. 26. Postpronotal lobe, lateral view. 27. Abdomen, dorsal view.

FIGURES 28–31. Curtonotum irksum sp. nov.. 28. Male terminalia, left lateral view. 29. Same, posteroventral view. 30. Same, external left lateral view. 31. Detail of distiphallus, dorsal view.