Tephrochlaena oraria Collin, 1943: 242

Giudice, Giuseppe Lo & Woźnica, Andrzej Józef, 2020, Revision of the genus Tephrochlaena, with a key to genera of Palaearctic Heteromyzinae (Diptera: Heleomyzidae), Zootaxa 4820 (1), pp. 165-176 : 170-173

Tephrochlaena oraria Collin, 1943: 242 . Type locality: “ Wales, Porthcawl , Glamorgan ”

( Fig. 6 )

Redescription [measurement of female specimens in parentheses, measurement of lectotype in brackets].

Length: 3.74–[4.05] 4.25 (3.35–4.40) mm.

Colour. Frons and fronto-orbital plates orange, brownish at sides of ocellar triangle in some specimens. Ocellar triangle brownish-grey. Occiput, genae, face (except for the yellow-orange central part) and parafacials whitish-yellow. Palpi orange. Antennae brownish-orange. Ocellar triangle, occiput, frontal vitta, central part of frons (slightly visible) and face below antennae covered with silver pruinosity. Arista brownish (orange in basal part). Prosternum yellowish-grey and covered with light silver pruinosity. Mesonotum greyish-brownish. Two dark grey stripes on mesonotum, extending between dc and reaching third postsutural dc. Postpronotum greyish-brown. Lateral part of thorax brownish-grey. Scutellum brownish-grey with brownish-orange tip. Legs brownish-yellow. Pulvilli yellowish. Wing membrane pale. Veins not darkened. Tegula and basicosta brownish-orange. Halteres brownish-yellow. Abdomen varying from entirely orange to brown.

Head ( Figs. 7–9 ). In lateral view about 1.08–1.18 [1.09] (1.14–1.20) times as high as long. Frons ratio 1: 1.09– 1.19 [1.12] (1.00–1.05). Frons ratio 2: 0.60–0.84 [0.71] (0.61–0.75). Vr/eye: 1.80–2.16 [1.84] (2.00–2.00). Ocellar setae inserted halfway between anterior and posterior ocelli or closer to anterior ocellus. Peristomal setae in one row. Anterior orbital seta about 0.65–0.88 [0.67] (0.57–0.90) times as long as posterior one. Postpedicel ratio: 1.03–1.25 [1.06] (1.03–1.25). Postpedicel/gena ratio: 0.63–0.81 [0.78] (0.60–0.75). Arista short pubescent, with hairs not longer than basal segment of arista. Second aristomere about two–three times as long as wide. Eye rounded. Gena/eye ratio: 0.45–0.61 [0.49] (0.33–0.64).

Thorax. Prosternum bare. First postsutural dc closer to suture than to second dc (rarely closer to second dc). Acrostichal setae in 5–7 unarranged rows between dc. Anepisternum bare. Proepimeron without setulae in addition to main seta. One strong katepisternal seta. Upper part of katerpisternum covered with setae (unarranged or arranged in 1–2 rows) approx. 1/4–1/5 as long as main katepisternal seta (shorter in females). Anepimeron bare. Scutellum with dorsal and ventral surface bare. Two pairs of well-developed marginal scutellar setae.

Legs. Fore femur with unarranged setae on posterodorsal and posteroventral surfaces. Mid femur with one fine seta on proximal ventral surface. One small dorsal preapical seta on all tibiae. Fore fourth tarsomere shorter than fifth.

Wing ( Fig. 5 ). Length: 4.00–4.54 [4.46] (4.90–5.30) mm. Width: 1.40–1.51 [1.50] (1.35–1.90) mm. First part of Costa, behind basicosta, with a strong ventral seta. Costal spines slightly longer than costal thickness. Mv ratio: 1.30–1.53 [1.36] (1.19–1.35).

Abdomen. All tergites setulose, with long marginal setulae on T3, T4 and T5 (distinctly shorter in females).

Male terminalia ( Figs. 10–13 ). Male genitalia large. T7 concave and about 2 times longer than T6. Anus ventrally-directed. Epandrium ( Fig. 10 ) large and convex, semiglobular in lateral view, with long and medium-thick setae. Cercus partially fused with epandrium, with 1 medium-long apical seta and scattered fine setulae. Hypandrium with pointed lobes of lateral arms ( Figs. 11, 12 ). Phallic complex ( Fig. 12 ) with long aedeagal apodeme. Postgonite with 2 medium-sized setae. Ejaculatory apodeme normally developed, rod-like, dilated proximally. Surstylus symmetrical, subrectangular, with short but thick setae on outer distal part and only few scattered setulae on distal surface: in a view perpendicular to the outer surface as in Fig. 13 .

Female terminalia ( Figs. 14–16 ). T6 subtriangular in lateral view and downwardly-directed, T7 slightly flattened and forming an open ring ventrally ( Figs. 14, 15 ). Anus ventrally-directed. Three globular spermathecae (two of them fused), sclerotized at base ( Fig. 16 ).

Biology. Rotheray (2015) noted that puparia of T. oraria were collected from a thin line of decaying seaweed deposited along the high-water line. In all probability, the larvae can develop on decaying organic matter like the seaweed Fucus vesiculosus (Patrick Grootaert, pers. comm.) or dead fish ( Lindroth et al. 1967; Lindroth et al. 1973).

Distribution. Tephrochlaena oraria is a West-Palaearctic coastal species, probably widely distributed along the seashores of the Mediterranean and East Atlantic coasts. According to Fauna Europaea ( Woźnica et al. 2013) and to its distribution in the different biogeographical regions ( Fig. 17 ), it seems to be an Atlanto-mediterranean species. Currently it is known from: Germany (Memmert), the Balearic Islands (Mallorca) (new data from Spain), the British Isles ( England, Scotland, Wales), Iceland [including Surtsey Island ( Baldursson & Ingadóttir 2007)], Ireland, Norway, Poland (Rügenwalde = Darłowo and not the Isle of Rügen, erroneous interpretation of the label “Rügenw” pointed out by Gorodkov 1984 as part of the type-locality), Spanish mainland, Tunisia and, in the last decade, from the Netherlands ( van der Weele 2013). Data on its presence in Bulgaria ( Beron et Guéorguiev 1967), Italy ( Caoduro et al. 1994), and Czechia ( Martinek 2001) are based on misidentifications and refer to species belonging to other genera. The material of “ Tephrochlaena halterata ” cited by von der Dunk (2006) from Bayern ( Germany) is unknown to us, but judging from the locality it belongs to the genus Tephrochlamys and the genus name should be removed from the Checklist of Bavarian Diptera .

Figures

FIGURE 17. T. oraria, distribution map (scale: 500 km).

FIGURES 4–9. 4. H. rotundicornis, male holotype (MZLU), wing. 5–9. T. oraria, ♂ (Wales, Oxwich). Wing (5). Habitus in lateral view (6). Head in lateral (7), frontal (8) and dorsal (9) view.

FIGURES 10–16. T. oraria, male and female terminalia. 10. ♂, epandrial complex in caudal view. 11–12. ♂, hypandrial com- plex in ventral (11) and dorsal (12) view. 13. ♂ (Wales, Oxwich), surstylus in a view perpendicular to the outer surface (scale: 100 µm). 14. ♀ (Wales, Oxwich), terminalia in lateral (a) and ventral (b) view. 15. ♀ (Wales, Oxwich), teminalia in dorsal (a) and ventral (b) view. 16. ♀ (Wales, Oxwich), spermathecae (scale: 50 µm). Abbreviations used in figures: epand = epandrium; c = cercus; ej apod = ejaculatory apodeme; hypd = hypandrium; pgt = postgonite; bp = basiphallus; aed apod = aedeagal apodeme; T1+2, T3, T4 etc. = abdominal syntergite 1+2, tergite 3, tergite 4 etc.; S1, S2, etc. = abdominal sternite 1, abdominal sternite 2, etc.