Saldula setulosa

Saldula setulosa (Puton, 1880)

is a halophilic species of shore bugs (Heteroptera: Leptopodomorpha: Saldidae) known from the Atlantic (England, France, and Portugal) and Mediterranean coasts (Spain, including the island of Menorca, Morocco, and southern France up to Camargue) (see Péricart 1990 and Fig. 1). I received for study an interesting specimen belonging to this species, collected in southwestern Sicily (Fig. 1) with a UV trap and preserved in 70% ethanol. The specimen was subsequently dry-mounted and examined under a stereomicroscope for identification. Habitus images were taken with a Leica M205 C stereomicroscope and dedicated software (Leica LAS v. 4.3) for Z-stacking at the Natural History Museum of the University of Florence. Genitalia were studied with a Nikon Eclipse C i -L compound microscope and photographed with an Asus ZE620KL camera (Sony Exmor sensor IMX363) and Nikon CFI Plan Achromat 20× objective. Line drawings were made with a Nikon Y-IDT drawing tube mounted on the latter microscope. Image processing was performed with Adobe Photoshop CS3 Extended (v. 10.0). Measurements were taken with ImageJ (v. 1.53) (https:// imagej.nih.gov/ij). The map was prepared using Google Earth Pro software (v. 7.3.6). Uncertainty of the data (in metres) was indicated according to the point-radius method (Wieczorek et al. 2004).

Material examined: ITALY: Sicily: Castelvetrano (Trapani), channel near the mouth of Belice River, 37.582843° N 12.872735° E (datum WGS84; uncertainty = 10 m; coordinates referring to the placement of the trap), 28.VI.2019, G. Pezzi legit (UV light), [original labels: Foce del Belice | (TP) 28-VI-2019 | G. Pezzi legit || alla luce UV], 1 submacropterous ♁ (Figs. 2, 3), collection F. Cianferoni, Florence, Italy.

Discussion: The specimen has a dense pubescence and numerous long, erect hairs on the pronotum (clearly visible in lateral view) and on the scutellum and anterior portion of the hemelytra. The only other species with these features occurring in Italy (and throughout the Euro-Mediterranean region) is Saldula pilosella (Thomson, 1871) s.l. (see Péricart 1990). However, several characters (cf. Péricart 1990) suggest the identity of the specimen to be S. setulosa: 1) the complete absence of a dark line on the fore tibia (Fig. 2a) vs. dark line always occurring in S. pilosella; 2) a pronounced angle on the outer edge of the parameres (Fig. 2b,c) vs. gently rounded in S. pilosella); 3) median endosomal sclerite narrowed at the base (Fig. 3) vs. not narrowed in S. pilosella); 4) body length 3.20 mm: the minimum size known for male S. setulosa (3.20–3.50 mm) vs. male S. pilosella (3.60–4.20 mm); 4) body width 1.43 mm: slightly below the range known for male S. setulosa (1.50–1.80 mm) vs. male S. pilosella (1.60–1.95 mm).

Further considerations concern the shape of the pronotum. The lateral margins of the pronotum are not explanate in the Sicilian specimen, which perfectly matches the pronotum of S. setulosa figured by Lindskog & Polhemus (1992, Fig. 9) and less so with that of the female represented by Péricart (1990, Fig. 64b) vs. the lateral margin of the pronotum more explanate in the male of S. pilosella (pers. obs.). However, the development of the pronotum also depends on wing development. The Sicilian specimen is submacropterous and Péricart (1990) stated that only this wing morph is known for S. setulosa [Péricart (1990) examined specimens from only 16 sites but representing almost all those known so far]; whereas the specimens of S. pilosella are “usually” macropterous.

The parandria (Fig. 2d), whose shape does not coincide perfectly with either of the drawings provided by Péricart (1990), have a curvature more similar to that of the drawing of S. setulosa. The hemelytra of the Sicilan specimen (Fig. 2a) are almost fully yellowish, except for a narrow black band in the proximal part of the corium (not represented in the hemelytral eunomic series of S. setulosa by Péricart 1990); possibly this represents the extreme form of light colouring. A few (not very evident) erect bristles occur on antennomere II (see Péricart 1990).

Distribution records for this species are very few throughout its range and Péricart (1990) considered it “rare everywhere”. The habitats of this species are “salty loam soils, especially along the coasts” (Péricart 1990). In fact, based on the few known sites, S. setulosa is known mainly from coastal areas, but also from interior brackish lagoons, including the salt lagoon of Sobralejo in southern Spain (over 100 km from the sea) and the lower course of the Aude river at Trébes, in southern France (over 50 km from the sea) (see Péricart 1990). As regards the Sicilian specimen, unfortunately there is little information to add to our understanding of the ecology of this species, given that it was collected with a UV trap. In any case, the discovery a few tens of meters from the sea is well compatible with what is known about S. setulosa. It would be useful in the future to deepen our understanding of the ecology of this species with detailed environmental characteristics where it is collected.

This finding extends eastward the distribution range of the species by almost 700 km (see Péricart 1990 and Fig. 1). This is also the first record of S. setulosa for Italy, adding another true bug species to the fauna of this country (cf. Cianferoni 2021), demonstrating how the knowledge on Heteroptera is still incomplete in this country (see e.g., Faraci et al. 2022 and Carapezza et al. 2023) and that there are still species (and populations) to be discovered in this group (see Cianferoni et al. 2017).