Efferia exaggerata Smit, 2019

Smit, John T., 2019, Robber flies from Sint Eustatius, Lesser Antilles, with the descriptions of Efferia exaggerata sp. n. and the male of Ommatius prolongatus Scarbrough (Diptera: Asilidae), Zootaxa 4586 (1), pp. 141-150 : 142-145

Efferia exaggerata Smit sp. n.

( Figs. 1–3 )

Type material. Holotype ♂. “Sint Eustatius, Caribbean / Netherlands, Oranjestad, building / CNSI 59 m 17.84944°N 62.98145°W / 8.x.2015 leg. J.T. Smit ”, “RMNH.5015328 [including a QR-code]”, “ HOLOTYPE ♂ / Efferia exaggerata sp.n. / Det. J.T. Smit 2018”

The holotype is in good condition, the genitalia were removed after taking photographs of the specimen and stored in a microvial on the same pin as the specimen, the right middle leg was removed for DNA barcoding.

Paratypes. 1♂. Same location as holotype, 15.x.2015, leg. S. Zwartsenberg; 1♀, Oranjestad 154 m, 17.47710°N 62.97576°W, 4.x.2015; 2♂, Oranjestad, Deep Yard, 17.48363°N 62.98625°W, 61 m, 13.x.2015; 1♀, Oranjestad beach, 17.x.2015, leg. E. Colijn; 1♀, NW Quill, 17.48739°N 62.95089°W, 65 m, 8.x.2015, leg. T. Huijts; 1♀ 2♂, NNW Quill, 17.47900°N 62.97158°W 233 m, 13.x.2015; 1♂ 2♀, NNW Quill, 17.47839°N 62.97177°W 215 m, 14.x.2015, leg. S. Zwartsenberg; 2♀ same location, 15.x.2015 .

Description of the male holotype ( Figs. 1A, C, D ).

Length, body: 14 mm; wing: 11 mm. Head. Face grey tomentose, somewhat more yellowish grey on the vertex. Vestiture black in the center, white medially and along oral margin. Face at antennae half as wide as one eye. Palpi and antennae with only black setae, frons with black and white setae intermixed. Occiput grey tomentose, setae mostly white with 5–6 slender black postocular bristles dorsally. Thorax. Pronotum yellowish grey tomentose, setae white. Scutum with a medial dark stripe, divided in the middle by a thin line of tomentum, and two lateral dark spots on either side. In dorsal view the medial line stops well in front of the scutellum leaving the posterior part of the scutum grey tomentose, with a triangular dark prescutellar spot. Seen from behind the tomentose and dark areas invert. Vestiture entirely black, the setae on anterior part short, on posterior 1/4 becoming longer, the longest as long as the dorsocentral bristles. Scutellum white-haired with a few black ones intermixed, two stronger black marginal bristles, and a few thinner mainly white ones present. Pleura entirely grey pollinose, or brownish grey depending on the angle. Halter brownish yellow. Wing. ( Fig. 1E ). Hyaline, costal cell brown, costal margin strongly dilated. Crossvein r-m at apical 1/3 of cell d. Base of cell r4 beyond apex of cell d. Legs. Coxae black, greyish white tomentose, vestiture entirely pale. Femora black, posterior orange spot smaller than width of the femur. First femur without bristles, white-haired with a few black ones intermixed dorsally. Bristles of mid femur black and white, on the hind femur white, only black apically. Tibiae all orange, somewhat darkened at the apex. Tarsi all dark orange, only last segment nearly entirely black. Abdomen. Tergite 2 dark brown tomentose dorsally, tergite 3 mostly white tomentose dorsally, tergites 4–7 entirely white tomentose dorsally. Tergite 8 black. Vestiture of all abdominal segments white, tergite 8 with a few black ones intermixed. Terminalia. ( Figs. 1D , 2 ). Black with black setae. Epandrium 3.5 times longer than wide, apically concave, giving it a beak like appearance. Gonostylus apically swollen and broadly rounded. Gonocoxa with black setae, long and equally dense over the entire length, apically with an evenly rounded, symmetrical notch.

Variation. Most paratypes have tergites 4–7 white tomentose, one specimen has tergite 4 dark and in two males the tomentum is invisible, probably due having become wet at some stage of the collecting. One male has the mid and hind femora extensively red posteriorly. Length: 14–19 mm, wing: 11–13 mm.

Female. ( Figs. 1B , 3 ). Same as the male except for the obvious sexual differences, the white tomentum on the abdomen confined to the lateral sides of tergites 2–7, sometimes more extensive in the posterior corners of the tergites. Abdomen in dorsal view grey pollinose, darker medially, but never dark tergites with posterior lighter grey dusted margins, as in females of E. nigrimystacea (Macquart) ( Fig. 4B ). Abdomen with predominantly white vestiture, only medially with some short black hairs. Length: 12–19 mm, wing: 10–14 mm.

Diagnosis. Efferia exaggerata sp.n. belongs to the aestuans -group as defined by Hine (1919) and Wilcox (1966), as do the majority of the endemic Caribbean species of this genus ( Scarbrough & Perez-Gelabert 2008; 2009). This group is defined by the wing venation: the fork of veins R 4 and R 5 is positioned posterior of the apex of cell d, and R 5 usually joins the costa below, rarely at or slightly above, the wing tip.

The male of E. exaggerata sp.n. differs from all other Caribbean Efferia species by the combination of the following characters: palpi with black setae, base of cell r4 beyond apex of cell d, costal margin of wing strongly dilated, abdominal segments 3–7 almost entirely white tomentose and epandrium 3.5 times as long as wide.

The female of E. exaggerata sp.n. differs from all other Caribbean Efferia species by the following combination of characters: Face at antennae about ½ wide as an eye, palpi predominantly with black setae, abdomen postpronotum and postalar callus not red, mystax with white bristles ventrally, abdomen with tergites 2–7 with white dusting laterally and with predominant white vestiture, only medially a few short black hairs.

This species is similar to E. stylata (Fabricius, 1775) , which occurs within the Greater Antilles as far southeast as the British Virgin Islands and the US Virgin Islands. In the key to the species of Puerto Rico and the Lesser Antilles provided by Scarbrough & Perez-Gelabert (2009, p. 45) both sexes will run to E. stylata . Both species are easily separated by the number of white tomentose abdominal tergites, the shape of the terminalia in the males and the stronger dilated coastal margin of the wing in E. exaggerata sp.n.. Females are easily separated by the width of the face, the amount of white tomentum on the abdomen as well as the abdominal vestiture.

Etymology. The specific epithet (adjective) refers to the extremely large terminalia, which, in flight, the male appears to drag behind him.

Distribution. Only known from Sint Eustatius, but probably more widely distributed in the northern part of the Lesser Antilles.

Figures

FIGURE 1. Efferia exaggerata sp.n. male holotype (A, C–E) and female paratype (B). A, B: lateral view. C: dorsal view. D: terminalia lateral view. E: right wing.

FIGURE 2. Efferia exaggerata sp.n. male terminalia of holotype. A: Epandrium. B: Gonocoxite. C: Phallus. D: tip of gonostylus.

FIGURE 3. Efferia exaggerata sp.n. female. Photo Marijke Kanters.

FIGURE 4. Efferia nigrimystacea (Macquart). A: male lateral view. B: female lateral view. C: right wing of male.