Aphrosylus salensis, Grootaert & Velde, 2019

Grootaert, Patrick & Velde, Isabella Van De, 2019, Empidoid flies from Cabo Verde (Diptera, Empidoidea, Dolichopodidae and Hybotidae) are not only composed of Old World tropical species, European Journal of Taxonomy 528, pp. 1-17 : 2-6

Aphrosylus salensis sp. nov. urn:lsid:zoobank.org:act:DD10D085-FFDD-4E40-B8BE-4E367DA1B063

Figs 1–2

Diagnosis

A small species (2.1–2.3 mm) with a very long apical spur on the fore tibia. Haltere with black knob. Legs entirely black. Male with silvery shiny palpus. Male cercus pale, in lateral view with apex broadened, bearing 2–3 long black bristles with a curled tip.

Etymology

The species is named after the Island Sal where it was found; ‘ salensis’ is Latin for ‘of the island of Sal’. The name of the island Sal refers to the salt found on the island.

Type material

Holotype CAPE VERDE • ♂; Sal, Santa Maria; 16°36′48.47″ N, 22°55′43.23″ W; 6 Feb. 2019; P. Grootaert and I. Van de Velde leg.; in the splash zone on rocks of a jetty; RBINS.

Paratypes

CAPE VERDE • 8 ♀♀; same collecting data as for holotype; P. Grootaert and I. Van de Velde leg.; in the splash zone of a rocky shore; RBINS • 2 ♀♀; Sal; Santa Maria; 16°37′27.26″ N, 22°55′51.09″ W; 3 Feb. 2019; P. Grootaert and I. Van de Velde leg.; in the splash zone of a rocky shore; RBINS .

Description

Male ( Figs 1–2 )

MEASUREMENTS. Body: 2.1 mm; wing: 1.9 mm.

HEAD. Eyes narrowly separated on face, at the shortest distance near middle, nearly as wide as scape. Clypeus narrow, protruding, densely covered with microtrichia. Palpus white in ground colour, oval, covered with silvery hairs, inner margin with some short black hairs. A pair of strong diverging ocellars, a pair of long proclinate verticals, a pair of short postverticals. Postoculars uniseriate, black, strongest on upper part of occiput, finer below.

ANTENNA. Black. Length of scape, pedicel, postpedicel and arista in mm: 0.09:0.065:0.156:0.39. Scape longer than pedicel. Postpedicel elongate onion-shaped, twice as long as wide and arista 2.5 times as long as postpedicel.

THORAX. Black in ground colour. A large humeral, a large posthumeral, four strong dorsocentrals decreasing in length towards scutellum. The basalmost longest, twice as long as most apical dorsocentral bristle. No acrostichals present. Two short notopleurals, a long post-sutural, a long supra-alar and a pair of long crossing scutellar bristles.

WING. Greyish tinged with black veins. Posterior cross vein twice as long as apical section of the cubital vein. Haltere with a black knob.

LEGS. Black.

FORE LEG. Coxa anteriorly covered with short black spine-like bristles. Trochanter with three short spines. Femur spindle-shaped on basal half, ventrally with a double row of bristles. The posterior row is limited to the basal half of the femur. The anterior ventral row contains shorter and finer bristles. A distinct papilla is present at the ventral base of the femur, bearing a strong, blunt, curved spine; a long posterior preapical. Tibia short, somewhat spindle-shaped, with a long apical projection bearing a long curved spine. The tip of the spine reaches the trochanter. Tibia with a short posterodorsal in basal quarter and a short posterodorsal in apical quarter. Ventrally with a row of bristles increasing in length from base onwards and ending with two longer bristles on the apical projection. Tarsomere 1 with a row of interspaced fine ventral bristles, continuing on the tarsomeres 2 and 3. Ratio of femur, tibia and tarsomeres in mm: 0.6:0.4:0.4:0:28:0.24:0.12:0.14.

MID LEG. Coxa with a short black apical spine, further covered with fine bristles, one fine exterior bristle. Mid femur thinner than fore femur. one anterior at apical fifth, one longer preapical anterior, a shorter preapical posterior. Tibia with a ventral row of very short bristles, a long anterior and long posterior near base, a long preapical posterodorsal and a long preapical ventral bristle two times as long as as width of tibia. Ratio of femur, tibia and tarsomeres in mm: 1:0.6:0.56:0.3:0.2:0.1:0.12.

HIND LEG. Coxa with a fine black exterior bristle. Trochanter with a long black dorsal bristle. Femur with four erect dorsal bristles in basal third as long as width of femur, in apical third with three long dorsal bristles longer than width of femur; one strong anterior and posterior preapical, ventral bristles lacking. Ratio of femur, tibia and tarsomeres in mm: 1:0.9:0.5:0.34:0.2:0.08:0.1.

ABDOMEN. Tergites black in ground-colour, covered with short bristles. Sternites brown, covered with minute pale hairs.

MALE TERMINALIA ( Fig. 2 ). Cerci whitish, somewhat dusky at tip. Epandrium black. Apex of cercus truncate, bordered with long black setae, some large setae with a curled tip ( Fig. 2A ). Base of cercus with a tubercle bearing a long seta ( Fig. 2B ). The tubercles of each cercus crossing. Apico-ventral epandrial lobe large, set with two setae on apex and one seta on a tubercle at the base ( Fig. 2A ). Ventral surstylus brown, with an enlarged apex bearing three setae ( Fig. 2C ). Dorsal surstylus with a large tubercle on inside bearing an apical seta directed to the base of the epandrial ( Fig. 2D ), with a second smaller protuberance at the base of the large tubercle, bearing a short seta pointing inward. Baso-ventral epandrial lobe small, with a single short seta.

Female

MEASURMENTS. Body: 2.1–2.3 mm; wing: 2–2.1 mm.

Similar to male in most aspects, especially the long apical projection on the fore tibia with the long spine. Scape, pedicel, postpedicel and arista in mm: 0.065:0.052:0.143:0.351.

FORE LEG. Ratio of femur, tibia and tarsomeres in mm: 1:0.6:0.66:0.28:0.2:0.12:0.22.

Tergites 3 and 4 at sides with a patch of small squamiform setae which are not present in the male.

Remarks

The new species is closely related to Aphrosylus calcarator Frey, 1945 from the Canary Islands, especially in having a very large spur on the fore tibia. In the male A. calcarator , the eyes almost touch on the face (“linien formig” sensu Negrobov 1979). In the new species the eyes are distinctly separated in the male by a distance of nearly the width of the scape; in the female the distance is even wider than the scape. In A. calcarator , the postpedicel is a little longer than wide and the arista is 3.5 times as long as the postpedicel ( Negrobov 1979: fig. 1573). In the new species, the postpedicel is longer, twice as long as wide, and the arista is 2.5 times as long as postpedicel. In A. calcarator , the ventral bristling of the fore femur has a different pattern, with the longest bristles in the apical ⅔, while in the new species the longest bristles of the posterior ventral row are in the basal half only. In A. calcarator , the fore tibia is as long as tarsomeres 1 and 2 together. In the new species, the fore tibia is relatively shorter, as long as tarsomere 1 only. In A. calcarator , tarsomere 1 of the fore leg is narrow and elongated and as long as tarsomeres 2, 3 and 4 together. In the new species, tarsomere 1 is shorter than the following three tarsomeres together. The wing in A. calcarator is dark brown tinged, while in the new species the wing is only greyish tinged. Sternite 4 in the male of A. calcarator seems to bear two short exterior appendages, while there are none in the new species. The male terminalia are different in both species ( A. calcarator in Negrobov 1979 : fig. 1575 and Fig. 2 for the new species).

Aphrosylus salensis sp. nov. differs from A. lindbergi , the only other known species from Cape Verde, in that the postpedicel in A. lindbergi is three times as long as wide. The haltere is white and apparently there is no long spur on the fore tibia. In the new species the postpedicel is twice as long as wide. The haltere is black and there is a very long spur on the fore tibia in both sexes.

Key to male Afrotropical Aphrosylus

Modified from Rampini & Munari (1987).

1. Knob of the haltere white (pale) ....................................................................................................... 2 – Knob of haltere black ........................................................................................................................ 3

2. Postpedicel three times as long as wide, arista longer than antenna ( Cape Verde) ............................ ........................................................................................................................ A. lindbergi Frey, 1958

– Postpedicel at most twice as long as wide, arista as long as antenna ( Sierra Leone) ......................... ....................................................................................................................... A. rossii Rampini, 1982

3. Palpus silvery ................................................................................................................................... 4 – Palpus dark, not silvery shiny .......................................................................................................... 5

4. Postpedicel triangular, as long was wide; apical spur on fore tibia long (tibia 2.3 times length of spur); cercus in male pointed in lateral view, without long bristles ( Senegal) .................................... ................................................................................................. A. gioiellae Rampini & Munari, 1987

– Postpedicel more bulbiform, nearly twice as long as wide; spur on fore tibia very long (tibia only 1.5 times as long as spur); cercus in lateral view with a wide apex bearing several long bristles, some with a curled tip ( Cape Verde) .............................................................................. A. salensis sp. nov.

5. Fore and mid femora with long ventral bristles; cercus small ( Sierra Leone)..................................... .......................................................................................................... A. cilifemoratus Rampini, 1982

– Fore and mid femora without long ventral bristles; cercus larger ( Senegal) ...................................... ............................................................................................... A. giordanii Rampini & Munari, 1987

Figures

Fig. 1. Aphrosylus salensis sp. nov., male holotype, habitus (leg. P. Grootaert and I. Van de Velde, RBINS).

Fig. 2. Aphrosylus salensis sp. nov., male holotype, terminalia. A. Epandrium, lateral view. B. Cerci, dorsal view. C. Ventral surstylus, lateral view. D. Ventral view of epandrium, below the epandrial lobes. E. Ventral view of epandrium. Scales: 0.1 mm.