Achradocera apicalis (Aldrich)

Runyon, Justin B., 2020, The Dolichopodidae (Diptera) of Montserrat, West Indies, ZooKeys 966, pp. 57-151 : 57

Achradocera apicalis (Aldrich) Fig. 18A, C

Chrysotus apicalis Aldrich, 1896: 330.

Achradocera angustifacies Becker, 1922: 207.

Material examined.

Lectotype (designated here to fix identity of the species) ♂, labelled: "St. Vincent/ W. Indies."; "Collection/ JM Aldrich"; "Cotype/ No.50426/ U.S.N.M."; " Chrysotus / apicalis / Type Ald. [hand written]"; "LECTOTYPE/ ♂ Achradocera / apicalis (Aldrich)/ des. JB Runyon" [red label] (USNM). Dominica: 5 ♂, 2 ♀, Springfield Estate, FIT trap, 29 May 2011, M.A. & L.L. Ivie; 1 ♂, same as previous, Malaise trap, 29 May-1 June 2011; 3 ♂, same as previous, yellow pan traps, 1-3 June 2011. Montserrat: 6 ♂, 2 ♀, Woodlands, Riverside House, 10-12 January 2002, Malaise trap, Ivie, Marske & Puliafico; 6 ♂, 1 ♀, same as previous, 5-7 January 2002; 3 ♂, same as previous, 17-28 July 2005, WIBF group; 3 ♂, Hope Ghaut, 8-10 January 2002, yellow pan traps, K.A. Marske; 1 ♂, Cassava Ghaut, Beattie House, 21 January-5 February 2002, Malaise trap, A. Krakower; 2 ♂, same as previous, 24 June 2005, yellow pan traps, V.G. Martinson; 3 ♂, Sweetwater Ghaut, 1 August 2005, yellow pan traps, V.G. Martinson; 3 ♂, Bottomless Ghaut, 5 August 2005, yellow pan traps, V.G. Martinson; 1 ♂, trail to Fairy Walk, 15 August 2005, yellow pan traps, V.G. Martinson; 2 ♂, Cedar Ghaut, 4 August 2005, yellow pan traps, V.G. Martinson; 1 ♂, Big River, 5 August 2005, yellow pan traps, V.G. Martinson. Nevis: 5 ♂, Camps River Ghaut, 17°11.36'N, 62°34.66'W, 25 May 2017, J.B. Runyon; 3 ♂, small pond, 200 m, 17°07.460'N, 62°35.584'W, 26 May 2017, J.B. Runyon; 1 ♂, The Source trail, 400-550 m, 17°08.76'N, 62°34.31'W, 26 May 2017, J.B. Runyon. St. Lucia: 6 ♂, 2 ♀, Escap Community, small stream in dry forest, 45 m, 13°49.92'N, 60°53.91'W, 2-3 May 2009, J.B. Runyon; 5 ♂, Savannes, Mangrove Reserve, 0-5 m, 13°45.97'N, 60°54.88'W, 3 May 2009, J.B. Runyon; 1 ♂, 1 ♀, trail, dry forest, 45 m, 13°49.9'N, 60°53.9'W, 6 May 2009, J.B. Runyon; 2 ♂, 1 ♀, Doree River ravine, 220 m, 13°47.962'N, 61°01.100'W, 7 May 2009, J.B. Runyon; 1 ♂, Fond Bay near beach, 13°49.89'N, 60°53.65'W, 8 May 2009, J.B. Runyon (MTEC, USNM).

Distribution.

Widespread in the West Indies, also reported from Mexico, Ecuador, Chile, and has recently dispersed (probably via accidental human introduction) to French Polynesia and Tonga ( Bickel 2000).

Remarks.

Aldrich (1902) synonymized Achradocera apicalis (Aldrich) with A. barbata (Loew), primarily due to the distinctive femoral coloration of both species. Robinson (1975) considered A. apicalis distinct by the much shorter antenna of the male. Bickel (2000) followed Aldrich (1902) and treated A. apicalis and A. barbata as synonyms, based again in part on femoral coloration and variation in male antennal length. However, comparison of photos of the holotype of A. barbata (MCZ) and specimens from North America (Alabama, Florida, Georgia, Indiana, Kentucky, Missouri, New York, Pennsylvania, Texas, South Carolina, Virginia) with A. apicalis from the West Indies (Dominica, Montserrat, Nevis, St. Lucia, St. Vincent) reveals that these species are distinct, most notably in the form of the male front tarsus and genitalia (Fig. 18 ). The A. barbata type and male specimens from North America all have a distinct series of ventral setae on tarsus I (Fig. 18B ) whereas specimens from the West Indies (including syntypes from St. Vincent) lack these setae (Fig. 18A ). The surstylus and phallus are also very different, with A. barbata having the surstylus enlarged and rounded apically and phallus dorsally serrate (Fig. 18D ; Bickel 2000: fig. 1a) but in A. apicalis the surtylus is smaller and pointed apically and the phallus is not serrate (Fig. 18C ; Bickel 2000: fig. 1e as A. barbata ). The antennal length in males of A. apicalis is highly variable, as noted by Bickel (2000), but in all available specimens is distinctly shorter than the antenna in males of A. barbata . Therefore, A. apicalis (Aldrich) is here removed from synonymy with A. barbata (Loew). The species described in Bickel (2000) as A. barbata is A. apicalis .

Figures

Figure 18. Tarsus I and terminalia of males A Achradocera apicalis (Aldrich), tarsus I, posterior view (Montserrat) B Achradocera barbata (Loew), tarsus I, posterior view (Kentucky, USA), arrows indicate ventral setae C Achradocera apicalis, tip of abdomen, left lateral (Montserrat) D Achradocera barbata, tip of abdomen, left lateral (Florida, USA). Scale bars: 0.25 mm (A, B), 0.5 mm (C, D).