Discotettix Costa, 1864

Skejo, Josip, Pushkar, Taras I., Kasalo, Niko, Pavlović, Marko, Deranja, Maks, Adžić, Karmela, Tan, Ming Kai, Rebrina, Fran, Muhammad, Amira Aqilah, Abdullah, Nurul Ashikin, Japir, Razy, Chung, Arthur Y. C. & Tumbrinck, Josef, 2022, Spiky pygmy devils: revision of the genus Discotettix (Orthoptera: Tetrigidae) and synonymy of Discotettiginae with Scelimeninae, Zootaxa 5217 (1), pp. 1-64 : 11-15

Genus Discotettix Costa, 1864

Discotettix : Costa 1864: 59; Bolívar 1887: 306; Rehn 1904: 670; Hancock 1907a: 6; Hancock 1907b: 213; Kirby 1910: 2; Willemse 1930: 7; Steinmann 1970: 216; Blackith 1992: 46; Yin et al. 1996: 866; Otte 1997: 32; Mahmood et al. 2007: 1275; Kočárek et al. 2015: 288–294.

Mnesarchus Stål, 1877: 55 ; synonymized with Discotettix by Bolívar (1887).

Type species: Discotettix armatus Costa, 1864 , by original monotypy, a junior synonym of Discotettix belzebuth ( Serville, 1838) .

Nomenclatural note. Many authors recently treat tettix as a noun originally of feminine gender. It is incorrect, as in all the Ancient Greek dictionaries the noun “ tettix, tettigos or tettikos, ho ” is of masculine gender. The word “ tetrix , tetrigos, he ” is however of feminine gender in Ancient Greek. Latreille (1802) introduced the name Tetrix (vernacular tétrix), but did not explain why he used the Ancient Greek name of a bird ( tetrix is the Ancient Greek name of the Pipit, still present in the name of the Black Grouse Tetrao tetrix ). Since then, the name Grouse Locust has been coined in the US, while the vernacular name pygmy grasshoppers has become more widely used. Even if Latreille did not want to relate pygmy grasshoppers to the bird and randomly invented the word “ tetrix ”, he used the word as feminine gender, which has to be followed ( ICZN 1999, Art. 30.1.4.2). Tettix is a masculine Ancient Greek word for grasshopper, introduced by Berthold (1827) as an (unjustified) emendation of Latreille’s name. The epitheta of all the Tetrigidae species whose genus is coined out from the word tettix should be in the grammatic masculine gender.

Diagnosis. The genus can be distinguished from all the other genera by the following set of characters: (I) frontal costa bifurcates between the lower third of the compound eye height (bifurcates below the lower third in other Discotettigini ), (II) scutellum narrower than scapus (of the same width or wider in Gavialidium , Paragavialidium , and Tegotettix ), (III) antenna 13-segmented (15-segmented in Gavialidium , Paragavialidium , and Tegotettix ), (IV) subapical antennal segments widened (filiform in most of Discotettigini ), (V) margins of the antenna saw-like (smooth in most of other Discotettigini ).

Comparison to former Discotettiginae genera. Among the former Discotettiginae genera (see Skejo 2017) the genus is similar to Kraengia and certain members of the genus Hirrius , i.e., H. montanus Günther, 1937 and H. sarasinorum Günther, 1937 from Sulawesi. Discotettix is similar to Kraengia in the general arrangement of pronotal protuberances (FM, FLs, MM, ML). However, in Discotettix the lower part of the lateral pronotal lobe is directed outwards forming a spine-like VL projection, while in Kraengia the lower part of the lateral pronotal lobe has a truncated margin. ML is more or less distinct in Discotettix species, while fully reduced in Kraengia , the humeral angle being obtuse. Additionally, Discotettix can be distinguished from Kraengia by the following set of characters: (1) 13 antennal segments (11 in Kraengia ), (2) large body size (more than 11 mm in Discotettix , less than 9 mm in Kraengia ), (3) presence of tegmen and wing in all Discotettix species ( Kraengia is wingless), and (4) distinct prozona with carinae (in Kraengia prozona is very short and carinae are usually not distinct). Discotettix can be distinguished from Hirrius montanus and H. sarasinorum by the following characteristics: (1) dorsal surface of the pronotum with protuberances and projections (in Hirrius the pronotum is almost flat, medial, mediolateral, and lateral projections are considerably reduced in size, hump-like or fully absent); (2) the lower part of the lateral lobe of the pronotum forms a sharp spine-like or saw-like VL projection (VL spine wanting or weak in Hirrius ); (3) tegmen and wing visible (not visible in Hirrius ).

Comparison to similar Scelimeninae: Discotettigini genera. The genus is morphologically similar to other Discotettigini genera, especially winged Bidentatettix , Disconius gen. n., Gavialidium , Eufalconius , Paragavialidium , and Tegotettix . Of all the mentioned genera, Discotettix is most similar to Disconius . From all the genera except for the Disconius , Discotettix can be easily distinguished by the widened antennomeres, while from Disconius it can be distinguished by the visible FM (reduced in Disconius ), by tuberculated median carina (continuous in Disconius ) and by strong FLs (almost absent in Disconius ).

Redescription of the genus Discotettix

General features. Medium and large sized species, robust in appearance. All the surfaces rough and granulated, rugose; pronotal disc wrinkled with numerous small tubercles and protuberances of different sizes and shapes. Macropronotal.

Coloration. Body color dark brown, ferruginous brown, or with brighter tints of brown; pronotal projections darker or differently colored than the rest (e.g., reddish or yellowish). Antenna black or dark brown, sometimes with pale-colored joints between the segments or with yellowish apical segments. Maxillary palpi dark brown, sometimes with darker distal margins of the last segment, or black with pale-colored joints between the segments. The visible part of the tegmen dark brown without spots. Legs dark brown except more or less distinct pale rings on tibia and tarsi and whitish 1 st tarsal pads.

Head. Head not elevated above the pronotum in lateral view. In dorsal view, the fastigium of the vertex considerably broader than a compound eye; the anterior margin of the fastigium truncated, widely excised, with protruded medial carina of the vertex, reaching not far from the anterior margin of a compound eye. In frontal view, the vertex slightly concave, indrawn from the considerably raised lateral carinae on the level of the upper margin of a compound eye; the medial carina of the vertex distinct in the anterior part of the vertex. Fossula present. Supraocular lobe absent. Lateral ocelli at the level of lower margin or between the compound eyes. Median ocellus far below the level of the lower margin of a compound eye, just between the facial carinae in the place where they end. Antennal groove just above the median ocellus, below or on the level of the lower margin of a compound eye. Frontal costa narrow, with the bifurcation a bit above or between the lateral ocelli. Frontal costa bifurcates into slightly divergent facial carinae forming a narrow scutellum, in lateral view with two concavities: the first large between the lateral ocelli and the second smaller below the antennal grooves. Maxillary palpi flattened. Compound eye in frontal view subglobular, in lateral and dorsal view drop-like, not protruding above the pronotum in lateral view. The occipital area between the eye and the anterior margin of the pronotum narrow, partly visible (more often not) from above ( Fig. 5C ). Antenna 13-segmented (but in male looks like 12-segmented, because 13 th segment very small and not visible under an optical microscope, only under SEM). Antennal segments as follows: 1 st massive scapus; 2 nd large pedicel; 3 th to 6 th basal elongated antennomeres; 7 th and 8 th central or subapical antennomeres, widened; apical 9 th small; 10 th to 13 th apical segments small, very reduced in comparison to others ( Fig. 1 ).

Pronotum. Pronotum wrinkled and granulated, covered by numerous small tubercles and larger projections. Posterior process of the pronotum slender, surpassing the hind knee for about a half of the hind femur length or more (macropronotal); covering the whole abdomen. Disc of pronotum: 1) more or less depressed behind the well-developed shoulder and gradually descending backward, or 2) almost at the same level along all length, without distinct depression behind the shoulder, and not descending backward. General arrangement of pronotal disc projections: pronotum with 4–7 unpaired projections of variable size on the medial carinae (FM and 3–6 medial projections); 1–3 pairs of FL projections; 1–7 pairs of more or less distinguished mediolateral projections; 1–3 pairs of lateral and a pair of more or less distinct VL (better seen in profile). In some species, some of the projections lacking or reduced. Prozona subsquare or wider than long (not taking into account FM). Anterior margin of pronotum truncated or projected, with a small or a large FM directed mainly upwards or forwards, sometimes covering a part of or the whole vertex. Prozonal and extralateral carinae in the prozona distinct, more or less elevated, surpassing the anterior margin of the pronotum as dentiform FL1 and FL2, where FL2 more distinct. FL3 dentiform, small and weak, sometimes indistinct. Median carina behind FM extended along the whole length of the pronotum, with 3–6 unpaired medial projections 4 of variable size, more or less distinct (seen very well in profile). PM small and triangular. MM1 large and triangular. MM2, MM3, and MM4 decreasing in size towards the apex of the pronotum (sometimes MM3 and MM4 reduced). MM5 present only in a few specimens of D. belzebuth . Usually, 1–7 pairs of the mediolateral projections increase in size towards MML1 (largest) and then decrease towards the tip of the pronotum (PML1 <PML2 <MML1> MML2> MML2> MML4> MML5). PML1 more or less distinct; PML2 distinct; MML1 small; MML2 large; MML3, MML4, and MML5 small, decreasing caudad (sometimes 1–3 of these posterior projections reduced). PL1 and PL2 small and triangular. ML more or less sharp, usually projected outwards. Interhumeral carinae indistinct, weak. External lateral carinae raised upwards above the base of the tegmen, in the posterior half smooth, not reaching the apex of the pronotum. Internal lateral carinae smooth, weak, usually indistinct. The infrascapular area triangular, as wide as the mid femur, fused to the lateral area. Lateral area narrower than the infrascapular and running towards the apex of the pronotum. The apex of the posterior pronotal process in the dorsal view shallowly excised or rounded. Hind margin of the pronotal lateral lobe bisinuate, ventral sinus deep, tegminal sinus small. The lower part of the lateral lobe with serrate anterior and posterior margins. VL elongated as spine-like, directed strongly outwards, sometimes forward or even slightly backward, but never downward ( Figs 2 , 5A, B ).

Wings. The visible part of the tegmen oval and elongated. Hind wing with scalloped inner margin, usually shorter than the pronotal process, not reaching its apex.

Legs. Femora robust, compressed laterally; with smooth or rough surface; dorsal and ventral margins finely or roughly serrate ( Fig. 29B ); genicular teeth visible on the knees; additional one to three teeth present on each margin. Fore and mid tarsi with distal segments longer than the proximal ones. Both sides of the upper margin of the hind femur finely serrated with distinct or indistinct lappets. Lateral area of the hind femur bears weak carinae with net-like elevations and outgrowths, especially on the ventro-external carina. Genicular teeth equal to or larger than the antegenicular. Hind tibia in dorsal view very slightly widened in basal and apical part. Both sides of the dorsal margin of the hind tibia finely serrated, usually with a few outer and large inner teeth. 1 st tarsal segment of the hind leg longer than 3 rd (without claws); 1 st and 2 nd basal pads of 1 st tarsal segment short and triangular, 3 rd (apical) elongated ( Fig. 1 ).

Abdominal apex. Male subgenital plate in ventral view triangular, longer than wide ( Fig. 31A, B ). Female subgenital plate in ventral view subsquare. Ovipositor elongated or robust. Valves of the ovipositor narrow, serrate ( Fig. 31C, D ). Epiproct in females as long as wide near the base, apex pointed. Cerci conical with narrowly rounded apex.

Composition and classification. The genus Discotettix is divided into two subgenera: (1) nominotypical Discotettix (type species D. armatus = D. belzebuth ) characterized by a long FM projected over the vertex; and (2) Mnesarchus Stål, 1877 stat. resurr. (type species Mnesarchus scabridus = Discotettix scabridus ) characterized by a minute FM, not projected over the vertex. The subgenus Discotettix includes six species. One species formerly assigned to Discotettix , that is D. shelfordi , has been transferred to a new genus, Disconius Skejo, Pushkar et Tumbrinck gen. n. The distribution of all the species is presented in Fig. 3 .

The annotated checklist of Discotettix species

1) Discotettix (Discotettix) aruanus Skejo, Pushkar et Tumbrinck sp. n. [Aru: Tanahbesar],

2) Discotettix (Discotettix) belzebuth ( Serville, 1838) [Borneo, Java (?)],

3) Discotettix (Discotettix) doriae Bolívar, 1898 stat. resurr. [Mentawai: Sipora],

4) Discotettix (Discotettix) kirscheyi Skejo, Pushkar, Tumbrinck et Tan sp. n. [Northeastern Borneo],

5) Discotettix (Discotettix) selysi Bolívar, 1887 [Peninsular Malaysia, Sumatra],

6) Discotettix (Discotettix) sumatrensis Skejo, Pushkar et Tumbrinck sp. n. [Southern Sumatra],

7) Discotettix (Mnesarchus) scabridus ( Stål, 1877) [ Philippines: Mindanao, Samar].

A key for the identification of Discotettix subgenera and species ( Fig. 4 )

1A) FM not projected above the vertex in lateral view (red arrow in Fig. 4 ). Shoulders unarmed. (Subgenus Mnesarchus ). The Philippines.............................................................................. D. (M.) scabridus

1B) FM projected above the vertex in lateral view (red arrow in Fig. 4 ). Shoulders armed with ML. (Subgenus Discotettix )..... 2

2A) Dorsum of the pronotum with high projections, as high or almost as high as the FM (compare the grey line in Fig. 4 )....... 3

2B) Dorsum of the pronotum flattened, usually no projection higher than the FM (gray line in Fig. 4 , exception is D. doriae where FM is reduced)....................................................................................... 5

3A) FM small (red arrow in Fig. 4 ). Dorsum of the pronotum with triangular projections (blue arrows in Fig. 4 ). Widest antennomere 8 th. NE Borneo..................................................................... D. (D.) kirscheyi sp. n.

3B) FM large (red arrow in Fig. 4 )........................................................................... 4

4A) Dorsum of the pronotum with high spikes (blue arrows in Fig. 4 ). Widest antennomere 8 th. Borneo........ D. (D.) belzebuth

4B) Dorsum of the pronotum with triangular projections (blue arrows in Fig. 4 ). Widest antennomere 7 th. Sumatra ............................................................................................ D. (D.) sumatrensis sp. n.

5A) FM small, not exceeding the head (red arrow in Fig. 4 ). Mentawai Isl.................................. D. (D.) doriae

5B) FM large, directed more upwards than forwards, usually not exceeding the head (red arrow in Fig. 4 )................... 6

6A) Larger species, pronotum length more than 20 mm in females. PM and MM1 lower and more oblique. Sumatra, Peninsular Malaysia.................................................................................. D. (D.) selysi

6B) Smaller species, pronotum length less than 17 mm in females. PM and MM1 elevated and more triangular. Aru Isl............................................................................................ D. (D.) aruanus sp. n.

Figures

FIGURE 1. Discotettix belzebuth (Serville, 1838), morphology of antennae. The first segment is scapus, the second is pedicel, and the rest are flagellum antennomeres. Drawing by Josip Skejo after the figure in Kuřavova et al. (2017). Scale bar = 1 mm.

FIGURE 2. Pronotum projections of Discotettix sumatrensis Skejo, Pushkar et Tumbrinck sp. n. numbered and named according to the proposed terminology: FL1—first frontolateral, FL2—second frontolateral, FL3—third frontolateral, FM— frontomedial, ML—metalateral, MM1—first metamedial, MM2—second metamedial, MM3—third metamedial, MM4—fourth metamedial, MML1—first metamediolateral, MML2—second metamediolateral, MML3—third metamediolateral, MML4— fourth metamediolateral, MML5—fifth metamediolateral, PL1—first prolateral, PL2—second prolateral, PM—promedial, PML1—first promediolateral, PML2—second promediolateral, and VL—ventrolateral.

FIGURE 3. Distribution map of Discotettix species.

FIGURE 4. The silhouettes of Discotettix species. The silhouettes are not to scale. The red arrow points to FM (frontomedial projection of the anterior margin of the median carina of the pronotum), while blue arrows point to the morphology of the dorsum (only one arrow if the dorsum is flattened, while more arrows show projections to be compared).

FIGURE 5. Discotettix belzebuth (Serville, 1838). A. dorsolateral view; B. dorsal view; C. frontal view. Photographs by Melvin Yeo. Reproduced with the author’s permission. Scale bar = 2 mm.

FIGURE 29. Discotettix kirscheyi Skejo, Pushkar, Tumbrinck et Tan sp. n. in a natural habitat near Tawau Hills Park in Sabah, Malaysia, Borneo. A. Dorsolateral habitus; B. head and pronotum detail. Photograph by Aglaia Bouma. Reproduced with the author’s permission.

FIGURE 31. Abdominal apex of Discotettix sumatrensis Skejo, Pushkar, et Tumbrinck sp. n. A, B. male paratype; C, D. female holotype. Photographs by Sergey. Storozhenko. Reproduced with the author’s permission. Scale bar = 0.5 mm.