Trichina rifensis Zouhair & Grootaert, 2022

Zouhair, Laila, Grootaert, Patrick & Kettani, Kawtar, 2022, First records of Trichina Meigen, Euthyneura Macquart and Oedalea Meigen (Diptera, Hybotidae) from North Africa, with descriptions of two new species, ZooKeys 1124, pp. 43-58 : 43

Trichina rifensis Zouhair & Grootaert sp. nov.

Figs 5A-D , 7E

Material examined.

Holotype. 1♂. Morocco, Rif , PNPB, Lemtahane, 964 m, 7.v.2017 - 30.v.2017, Malaise trap, leg. K. Kettani, PCLZ.

Habitat.

(S4: Lemtahane) (Fig. 4 ): The Malaise trap was set up in a scrubland composed of Pinus pinaster and some fruit trees growing on siliceous soil. The bioclimate is subhumid and favours thermo-Mediterranean vegetation.

Differential diagnosis.

The newly described species Trichina rifensis sp. nov., is very similar to T. opaca as it is described in Chvála (1983) and according to the key of Trichina in Barták and Kubík (2009) and to our T. opaca specimen, in: the absence of the ventral spine in hind trochanters, and in the colour of legs which are extensively blackish to blackish brown, with the knees and extreme base of tibiae often paler. It is similar to T. opaca also in having the same number of scutellar pairs setae (3 pairs). The wings are conspicuously darkened brown, veins blackish, squamae including fringes and halters deep black in both species. However, both species differ in the pruinosity of the mesonotum: in the new species, the mesonotum is shining black but anteriorly there is a very narrow stripe with weak microtrichia and the notopleural depression is more distinctly set with microtrichia (not grey dusted), while in T. opaca the mesonotum is entirely thinly brownish pollinose and consequently rather dulled, and differ also in the length of the 3d antennal segment that is less than 3.2 times as long as broad in T. opaca , while it is more than 3.2 times (4 times) as long as broad in T. rifensis sp. nov. The male terminalia in the new species is with the hypandrial projection much longer than in T. opaca , the structure of the left surstylus is similar in the two species so that is C-shaped in both. The right surstylus of the new species is spiny in the apical and sub-apical parts contrary to T. opaca , which forms an important differential diagnosis character, cerci are equal in length and shape in T. opaca , while in the new species, the left cercus is narrower and longer than the right cercus which is shorter and conical in shape.

Etymology.

The new species is named Trichina rifensis , after the Moroccan Rif region where it was found.

Description.

Male. Black species with body small (3 mm) Fig. 7E .

Head. Black in ground colour. Eyes meeting on frons for a long distance. A distinct prominent ocellar tubercle with 2 pairs of ocellar bristles, anterior pair as long as posterior one, occiput and vertex finely greyish pollinose, covered with black and distinct hairs. Face linear, narrow less than width of scape. Antennae entirely black, inserted at middle of head in profile with postpedicel is 0.24 mm long over 0.06 mm wide, stylus (apical naked part missing) has the basal part and the thickened second segment 0.079 mm long. Palpus short with a very long black apical bristle, 1.5 times as long as palpus and a subapical bristle half as long as apical one. Proboscis yellowish, pointing obliquely forward and covered with several brownish hairs.

Thorax. Polished black with all hairs black and long. Acr biserial, dc uniserial, ending in 1 pair of very long prescutellars, 1 humeral, 1 notopleural, 1 postalar bristles, 3 scutellar pairs. Mesonotum covered with microtrichia. Mesonotum shining black but anterior part with a very narrow stripe with weak microtrichia, notopleural depression more distinctly set with microtrichia (not grey dusted). Wings conspicuously brownish, stigma blackish brown extending to tip of vein R2+3, veins blackish brown, costa reaching vein M1, squamae, including fringes, and halters black. Legs mostly covered with hairs, extensively blackish leaving base of hind tibia and knees paler. No spine on hind trochanter. Fore femur rather slender, covered with paler hairs and bearing 6-8 black bristles apically; mid femur with 2 rows of paler bristles and 2-4 black bristles apically; hind femur much longer than fore and mid femora with ventral and dorsal paler bristles. Fore tibia rather slender, with black hairs; mid tibia with distinct a pair of black and strong bristles; hind tibia much longer than fore and mid tibiae, laterally compressed and dilated towards tip, with 2 rows of black bristles, with one dorsal black bristle.

Abdomen. Tergites and sternites blackish, covered with scattered black setulae. Terminalia black, with right surstylus somewhat robust and spiny in sub-apical and apical parts (Fig. 5B, D ), left surstylus slender and hypandrial projection long and slender. Right cercus shorter, conical, left cercus longer and narrower (Fig. 5B ).

Female. (Unknown)

Abbreviations: ae: aedeagus (phallus); cer: cercus; hyp: hypandrium; hypp: hypandrial projection; lel: left epandrial lamella; ls: left surstylus; rel: right epandrial lamella. rs: right surstylus.

General comments.

Despite the male terminalia of the two new species described above being very similar in structure, it is easy to distinguish between the both species: Trichina azizi sp. nov. has yellowish hind trochanters, femora tibiae and metatarsi, so it is very distinct from Trichina rifensis sp. nov., which has entirely black hind trochanters, femora, tibiae (except at base) and tarsi, as may be seen in Fig. 7D, E .

Compared to other species of Trichina described so far, Trichina rifensis sp. nov., is very close to Trichina opaca in most morphological characters (colour of legs and wings, shape of antennae, number of scutellar pairs, absence of hind trochanters spine(s)) but as we previously noted in the differential diagnosis to this new species, it differs clearly in the male terminalia. As to Trichina azizi sp. nov., is similar to T. elongata in the shape of the antennae, number of scutellar pairs and absence of the trochanter spine, but it is easy to differentiate these species by the male terminalia as we have described in the differential diagnosis above. The common character between the right surstylus of the both new species is that they are spiny, which is a character not described in Trichina at all.

Figures

Figure 4. Type habitat of Trichina rifensis Zouhair & Grootaert sp. nov., in Lemtahane (Photo: K. Kettani, 07.05.2017).

Figure 5. Trichina rifensis Zouhair & Grootaert sp. nov., Holotype male terminalia A right surstylus, lateral view B epandrium, dorsal view C left surstylus, lateral view D epandrium, ventral view. Scale: 0.1 mm. (Drawn by Patrick Grootaert).

Figure 7. A Trichina elongata Haliday, 1833 B Trichina opaca Loew, 1864 C Trichina unilobata Chvala, 1981 D Trichina azizi Zouhair & Grootaert sp. nov. E Trichina rifensis Zouhair & Grootaert sp. nov. (Left antennal style missing) F Euthyneura myrtilli Macquart, 1836 G Oedalea portugalica Bartak & Grootaert, 2021.