Curtonotum prolixum 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 : 547-550

Curtonotum prolixum Lindsay , sp. nov.

Figures 32–39

Differential diagnosis. Distinguished from its congeners by the inner lobe of the surstylus, which is 10–15 times as long as wide and flat and by the distal distiphallus, which has a leaf-like lobe that is medially sclerotized. The upper projection of the distiphallus is curled and wider apically and the lower projection is slightly sclerotized and stout ( Fig. 39 ). Curtonotum prolixum generally lacks pronounced dark bands on the posterior margins of tergites 3–5 ( Fig. 35 ). Females are here treated as indistinguishable.

Description. Male: Overall length (excluding wings): 4–8 mm.

Head: Vibrissa subequal to subvibrissal setae. Parafacial broad, gena approximately 1/3 width of postpedicel. Postpedicel 1.5–2 times length of pedicel. Arista with 7–9 dorsal branches, 4–6 ventral branches.

Thorax: Scutum often with distinct grey dorsal markings. Postpronotal lobe with 3 setae (1 long, 2 shorter subequal) and sometimes several poorly defined setulae ventrally. Line of setulae above fore coxa black.

Legs: Hind femur with a dark brown preapical band (sometimes very weak).

Wing: Light grey-brown, with slight infuscation around crossvein dm–m and at anterior margin.

Abdomen: Tergite 2 with 2 posterolateral markings covering 1/4 length of tergite. Tergites 3–5 with dark median vitta, sometimes absent from tergite 3 and thin, mottled, lateral triangles. Band on posterior margin of tergites 3–5 adjoining medial and lateral markings either entirely absent to present and covering approximately 1/10 of tergite 3.

Male terminalia: Cercus very elongate, equal to or longer than, epandrium at widest point. Surstylus thin and straight, modified into 2 lobes. Inner lobe black, flat and elongate, 10–15 times as long as wide, outer lobe 2–3 times as wide as inner. Postgonite notched dorsally. Hypandrium lacking dorsobasal projection. Phallapodeme thin, shorter than epandrium. Distiphallus with elongate distal leaf-like lobe, with microtrichia on lateral edges and line of medial sclerotization. Upper projection long and recurved with wider tip, lower projection stout and weakly sclerotized.

Female: Unknown.

Etymology. From the Latin, prolixo, meaning “elongate”, which refers to the long and slender cercus and surstylus of this species.

Comment. Four females matching the general external diagnosis of C. prolixum sp. nov. from Mexico were dissected, but no distinct terminalia characters could be identified to diagnose females of the species.

Type material. Holotype: ♂: MEXICO. Jalisco: Guadelajara, [20°40’33.96”N, 103°20’49.199”W], 1909, Mc- Connell ( CMNH) . Paratypes: MEXICO. Jalisco: ♂, IX.1954. F.X. Williams ( CASC) ; ♂, Guadelajara , 8.VIII.1903, “Mcdelendon.” ♂, Jalisco, 17.IX.1970, G.E., R.M. Bohart ; ♂, Jalisco, 1.XI.1971, W.J. Hanson ; ♂, Jalisco, 17.IX.1970, G.E., R.M. Bohart ( EMUS) ; ♂, Jiquilpam - Colima, 134 km, 1220 m, 14. IX.1950, A.M. De Baum ( USNM) . Sonora: 2♂, Rancho El Cajon, 40 km E Alamos, bench of Rio Cuchujuqui , riparian tropical deciduous forest, 420 m, 27°03.00’N, 108°43.91’W, 1–11.X.2006, M.E. Irwin ( DEBU) .

Other material examined. MEXICO. Chiapas: ♂, Agua Cero , 18.V.1985, A. Freidberg ( USNM) . Jalisco: 4♀, Guadelajara IX.1954. F.X. Williams ( CASC) . “ Jimez , 1950, W.D. Downe ” ( USNM) . ♀, Jalisco, 13 mi N Gua- delajara, 1.IX.1971, W.J. Hanson; Jalisco , 17.IX.1970, G.E., R.M. Bohart ( UTAH) . Sonora: 3♀, Rancho El Cajon, 40 km E Alamos, bench of Rio Cuchujuqui , riparian tropical deciduous forest, 420 m, 27°03.00’N, 108°43.91’W, 1–11.X.2006, M.E. Irwin, Malaise on sand ( DEBU) . UNITED STATES OF AMERICA. Arizona: ♀, Sta. Cruz Co., 6–8.IX.1979, W.J. Hanson ( EMUS) .

Figures

FIGURES 32–35. External characters of Curtonotum prolixum sp. nov.. 32. Habitus, lateral view ♂. 33. Head, anterior view. 34. Scutum, dorsal view. 35. Abdomen, dorsal view.

FIGURES 36–39. Curtonotum prolixum sp. nov.. 36. Male terminalia, left lateral view. 37. Same, posteroventral view. 38. Same, external left lateral view. 39. Detail of distiphallus, dorsal view.