Tetraconcha laszloi n. sp.

Figs. 30a–30c

urn:lsid:zoobank.org:act: 8103B4DB-03F8-4BD9-8681-87AAC633C00E

Material examined. Republic of Congo, Sangha prov., N-N NP, Mondika camp (352m) 02°21’50.63”N, 16°16’25.82”E, 7–14.II.2023, Actinic light trap, N.M. Bakala, V . Dérozier, A. Kirk-Spriggs, G. László (♁ holotypus) (ANHRT) .

Description. Male. Colour. Brown, with yellowish venation, abdomen yellow, cerci brown (Fig. 30a). Head and antennae. Fastigium of vertex narrow, apically furrowed, separated from fastigium of frons. Eyes rounded, well projecting. Antennae long. Pronotum narrowing anteriorly, flat above, anterior margin incurved, posterior margin rounded, humeral sinus well developed, lobes of pronotum rounded. Legs. Fore coxae armed with a thin spine. Fore tibiae furrowed dorsally, distinctly widening above tympanum, conchate on both sides. Fore femora armed on inner ventral side with 8 spines, fore tibiae with 7 spines + 1 spur on inner and 5 spines + 1 spur on outer ventral sides, 5 spines + 1 spur on outer dorsal side, mid femora armed with 5 spines on outer ventral side, mid tibiae with 13 spines on outer and inner ventral sides + 1 spur on each side, and 3 spines + 1 spur on inner dorsal side, hind femora armed with 4 small spines on outer and 4 on inner ventral sides, hind tibiae with many spines on ventral and dorsal sides + 3 spurs on each side. Tegmina narrow with rounded apices, hind wings longer than tegmina. Stridulatory area of left and right tegmina as shown in Fig. 30a; stridulatory file 2.1 long, arched and composed of ca. 50 evenly spaced teeth (Fig. 30b). Distance between left tegmen base and max width of lower cubital area 5.0 mm, size of upper and lower cubital areas 1.1 and 1.3 mm. Abdomen. Subgenital plate short with a V-shaped concavity, with two style-like appendices, cerci stout and incurved (Fig. 30c).

Female. Unknown.

Measurements (mm). Male. Body length: 17.8; length of pronotum: 4.8; depth of pronotum: 3.2; length of hind femora: 24.8; length of tegmina: 33.0; depth of tegmina: 5.8.

Etymology. Tetraconcha laszloi n. sp. is with pleasure dedicated to Gyula László (ANHRT), who participated on some expeditions in tropical Africa, collecting interesting species of Orthoptera .

Affinities. Tetraconcha laszloi n. sp., the eighteenth species of the genus, should belong to the group of T. smaragdina Brunner con Wattenwyl, 1891, the differences from related species lying in the stridulatory file and stridulatory area. They are highlighted in Table 2 and Fig. 31.

Remarks on the genus Tetraconcha

The genus Tetraconcha Karsch, 1890 was revised by Massa (2017), with another species described more recently (Massa 2021a). This genus has evolved less in morphological characters, but more in the acoustic signals. Indeed, the best way to identify the species belonging to this genus is to observe the shape and number of teeth of the stridulatory file under the left tegmen. This enabled the discovery that in central-western tropical Africa presently eighteen species live, some of them syntopically. Certainly, it is the different songs produced by the stridulatory apparatus that allows the separation of the species. A possible process of sympatric (more than allopatric) speciation likely occurred among the populations of Tetraconcha, originated from ecological specialization or simply sound differentiation.

The Sangha Trinational Protected Area proved to be the region with the greatest diversity of species in this genus, probably due to the variety of vertically distributed microhabitats in the primary forests. It is likely that more unknown species of this genus will be discovered in the future, which have so far gone unnoticed due in part to the difficulty of identifying differential diagnostic characters. To contribute to a better knowledge of the genus, Table 2 shows some measurements of the stridulatory file and stridulatory area, and Fig. 31 the stridulatory files of the most related species, mainly belonging to the smaragdina group.