Tessellana Zeuner, 1941

Massa, Bruno & Fontana, Paolo, 2011, Supraspecific taxonomy of Palaearctic Platycleidini with unarmed prosternum: a morphological approach (Orthoptera: Tettigoniidae, Tettigoniinae), Zootaxa 2837, pp. 1-47 : 8-10

3) Tessellana Zeuner, 1941 ( Figs. 2 , 43–47 , 64, 80, 107)

Characters. Head as wide as long, ratio maximum width/length of head (from vertex to clipeus): 1.0–1.1. Pronotum slightly depressed above, keeled mainly in the metazona ( T. carinata is keeled on the entire pronotum), humeral excision present at 4/5 of its length, less evident than in Platycleis ; Ƥ subgenital plate with a median furrow; ovipositor very short, rapidly tapering and sharply bent upwards near the base; Ƥ VII th sternite with a sharp longitudinal ridge; hind femora/pronotum length 3: 3.4–4.2, Ƥ: 3.5–4.3; 3 X th tergite with two short processes, apically rounded or pointed. Titillators are very small and with thorny apex, basal arms with spines. Differing from other related taxa (in which eggs are brownish), eggs of Tessellana are black. Colour of lateral lobes of the pronotum is blackish-grey bordered with a white stripe.

Remarks. Tegmina are much variable, some species are macropterous with some micropterous specimens, while others are only micropterous. Zeuner (1941) also tentatively included within this taxon also one species, later transferred to Decorana ( D. seniae ) (see below), but maintained by Ragge (1990). The shape of the pronotum of Tessellana is similar to that of Montana stricta , but other characters indicate the separation of Tessellana from Montana . Tessellana is clearly different from Platycleis and separated from it, both on the base of pronotum shape, male processes and ovipositor shape. Additionally, Incertana and Sporadiana , considered by some authors (cf. Table 1) synonyms of Tessellana , are also separated from the latter (see below).

Distribution. It has a palearctic distribution from Turkey and the Caucasus to central Europe and the Mediterranean (N Africa included); T. tessellata has been introduced in N America (California: Strohecker 1955).

Number of species known (after Eades et al. 2010, modified): 6 (in parentheses specimens examined): 1) carinata ( Berland et Chopard, 1922) (3 males and 1 female from Macedonia, 2 males and 2 females from Greece); 2) lagrecai Messina, 1979 (38 males and 17 females from the type locality: Ficuzza, Sicily); 3) nigrosignata ( Costa, 1863) (29 males and 21 females from South Italy); 4) orina (Burr, 1899) (58 males and 62 females from Greece and Albania); 5) tessellata (Charpentier, 1825) (type species) (20 males and 20 females from Italian peninsula, 7 males and 10 females from Sardinia, 4 males and 4 females from Corsica, 4 males and 4 females from Lampedusa Is. (Sicilian Channel), 30 males and 25 females from Sicily (with different wing length), 2 males from Tunisia, 1 male and 1 female from France, 2 males and 1 female from Spain, 2 males from Slovenia, 5 males and 2 females from Georgia and Armenia); 6) veyseli (Koçak, 1984) (20 males and 18 females from Serbia, Hungary, Albania, Georgia and Armenia).

Taxonomical note. Authors (e.g. La Greca 1959, Harz 1969, Willemse 1984, 1985, Çiplak et al. 2002) generally consider Tessellana nigrosignata present in the Balkan peninsula and Turkey. It has been described by Costa (1863) from Calabria ( Italy), and differs from Balkan specimens, which should be identified as T. orina . There are actually in the Balkan peninsula two species of Tessellana , namely T. orina and T. carinata , generally considered a synonym of T. nigrosignata . We report here historical records that caused this uncertain status.

After the description of Tessellana nigrosignata (type locality: South Italy, province of Reggio Calabria) two other related species were described, namely T. orina (type locality: Bosnia-Herzegovina) and T. carinata (type locality: Macedonia, Vakoufkoi, NE of Florina). When Berland & Chopard (1922) described T. carinata on a single specimen, pointed out that it is smaller than T. orina and shows all the pronotum keeled. Uvarov (1924) studied the types of T. orina and established the synonymy carinata Berland et Chopard, 1922 = orina Burr, 1899 = nigrosignata Costa, 1863 ; however, he did not examine Italian material of nigrosignata and the type of carinata . The types of nigrosignata are lost, but the species has been collected in different localities of South Italy (Campania, Basilicata, Calabria and Apulia: La Greca 1959, pers. obs.). Comparison of the Italian specimens with those collected in the Balkan peninsula and considered T. nigrosignata was needed to establish if this species actually covers other regions other than South Italy. We examined many European and Anatolian specimens (preserved in MSNM, PFCV and BMCP, cf. above examined material) that allowed us to state that even if Italian specimens are very similar to T. orina (which lives in the Balkan peninsula and Turkey), they differ for some characters; additionally T. carinata proves to be a valid species and its distribution has to be determined better by checking specimens preserved in museums and collections, some of which are possibly erroneously labelled as T. nigrosignata / orina .

Biometrics distinguish between (mainly in the males, Table 2 ) the above cited three species, in particular if the length of pronotum is plotted with the ratio length of hind femora/length of tegmina ( Fig. 47 ). T. carinata is a very small species well characterized by its evident keel on the pronotum ( Fig. 44 ), while in T. orina and T. nigrosignata the keel is evident only in the metazona ( Fig. 43 ). In addition, the radius sector of tegmina in T. nigrosignata and T. orina has a different shape, being a median veinlet in T. nigrosignata closer to cubitus than in T. orina ( Figs. 45– 46 ).

We also included in the Fig. 47 other Tessellana so far described and considered valid species. T. veyseli , well characterized by the shape of tegmina (pointed) and the VII th female sternite (whose tip exceeds the fore margin of the subgenital plate), is biometrically more related to T. tessellata , but has longer femora than it; interestingly, also songs of them are much similar ( Heller 1988, Ragge 1990), as well as those of other Tessellana ( Ragge & Reynolds 1998) . Concerning T. tessellata , it is seen to be very variable, in particular in Sicily, where there are populations characterized by different length of wings; one of them has been named T. lagrecai . Nevertheless, many differences in biometrics of these taxa proved to be significant (Kruskal-Wallis test and multiple comparisons by Wilcoxon test; cf. Tables 2 a, 2b).

Pairs of species Pronotum length Length of tegmina Length of hind femora

Figures

FIGURE 47. Measures (in mm) of pronotum length of different species of Tessellana plotted on the ratio ‘ length hind femora / length of tegmina’ to show different position of the species. Above males, below females.

FIGURES 1 – 10. Lateral view of the pronotum of 10 species of Platycleidini (Platycleis, Tessellana, Montana, Sardoplatycleis, Modestana, Alticolana, Parnassiana, Ariagona, Amedegnatiana).

FIGURES 43 – 46. 43) and 44) Pronotum of Tessellana nigrosignata and T. carinata from above to show median keel; 45) and 46) Tegmina of T. nigrosignata and T. orina to show the different pattern of veinlets.