Disconius shelfordi (Hancock, 1907) Skejo & Pushkar & Kasalo & Pavlović & Deranja & Adžić & Tan & Rebrina & Muhammad & Abdullah & Japir & Chung & Tumbrinck, 2022

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 : 54-55

Disconius shelfordi (Hancock, 1907) , comb. n. ( Figs 34–36 )

Vernacular name: Bornean Fallen Pygmy Devil

Discotettix shelfordi Hancock, 1907b: 214 [original description, type locality: Borneo]; Kirby 1910: 575 [listed in the catalog]; Günther 1938: 303 [in review]; Yin et al. 1996: 866 [listed in the catalog]; Blackith 1992: 47 [listed in the catalog]; Otte 1997: 32 [listed in the catalog].

Type locality. Malaysia: Borneo : Kuching

Note on the syntypes. The species description was based on two syntypes (male and female) labeled as “NW Borneo: Kuching, 22.IX.1899, Collector Dyak (Bornean native), det. J.L. Hancock ” and kept in the Oxford University Museum. As both specimens have been collected at the same locality and date, it is unlikely that they belong to different species. Thus, there is no need for lectotype designation.

Material examined.

Type material. SYNTYPE 1♀ NW Borneo: Kuching, 22.IX.1899., Collector Dyak, det. J. L. Hancock ( Fig. 34 ) ( OUMNH) ; SYNTYPE 1♂ NW Borneo: Kuching, 22.IX.1899., Collector Dyak, det. J. L. Hancock ( OUMNH) ;

Additional museum material. 2♀♀, 1♂ Indonesia: NE Borneo: Pajau River , leg. Mjöberg, det. J. Tumbrinck ( Fig. 35 ) ( NHRS) .

Additional material from online social media (iNaturalist): 1 adult Borneo : Malaysia: N Sarawak: Marudi (N4.041847, E114.8144) observed 15.X.2019., submitted on 5.II.2020. Photograph by Kinmatsu Lin (@kinmatsu), available at link inaturalist.org/observations/38326084 ( Fig. 36 ) .

Distribution: Known only from N Borneo; in Sabah from the surroundings of Kuching (type locality) and from the region of the Pajau River; and from Sarawak reported from Marudi ( Hancock 1907b; our data).

Redescription. ( Figs 34 , 35 )

General features. Medium-sized species (body length 14.0– 15.8 mm) (in the original description stated as 17.5–19 mm, but it meant from the tip of the head to the tip of the pronotum), relatively slender. The entire body finely granulated, covered by numerous small tubercles and with a few larger ones on the margins of the pronotal disc and the lateral lobes; in lateral view the pronotum almost flat, except for the median carina undulated by a few small wart-like and medium-sized semicircular compressed protuberances ( Figs 34 , 35 ). Macropronotal form.

Coloration. Body color from dark brown and ferruginous brown to brown with an inexpressive grayish tint. Some parts of the body pale colored, previously yellowish: tubercles on the margin of the disc and lateral lobe of pronotum, VL and ML, connections of dark antennal segments, patches on femora, more or less distinct ring in the middle of fore and mid tibiae, two rings (I) in basal and (II) distal third of the hind tibia, distal segments and claws of fore and mid tarsi, and usually yellowish hind tarsus (except for the darker connections of tarsal segments). Living specimens have much more vivid coloration than the museum material. It is visible that the dorsum of the pronotum has an alternation of dark and pale tones (see iNaturalist observation in Material examined).

Head. In dorsal and frontal view, vertex about 2.4 times as wide as the eye. Fossula visible, but not deep. Lateral ocelli situated between the compound eyes. The antennal groove situated at the level of the lower margin of the compound eye (in males) or a bit below (in females). In frontal view frontal costa narrow, bifurcates a bit above the lateral ocelli into a slightly divergent facial carinae, slightly concave inside in medium length and forming a narrow hour-glass shaped scutellum ( Figs 34C , 35C ). Antennal groove considerably wider than scutellum. Antennae 15 segmented, long. Antennomeres are shaped as follows: scapus (1 st antennomere) massive; pedicel (2 nd antennomere) large, basal antennomeres (3 rd to 7 th) elongated, 7 th being extremely elongated; central or subapical segments 8 th to 10 th pennate, 8 th slightly widened, while 9 th, and 10 th significantly widened and flattened; apical segment 11 th small; while apical segments 12 th to 15 th reduced in size, filiform.

Pronotum. Pronotum finely granulated, covered by numerous small and few larger tubercles on the margin of the disc and the lateral lobe of the pronotum; almost flat, except for the wrinkled and scalloped median carina with small wart-like and medium-sized, compressed laterally, semicircular protuberances (different in specimens from different geographical populations); posterior process of pronotum very long, surpassing the hind knee for more than a half hind femur length (macropronotal form). Disc of the pronotum almost of the same height in the anterior part, slightly depressed behind the level of the tegmen apex and gradually descending backwards. Morphology of the pronotal projections variable. Pronotum with 5 unpaired projections of variable size on medial carina (FM and 4 medial projections); 2–3 pairs of FL; a pair of VL (better seen in profile); while among the mediolateral and lateral projections only one projection distinct per group. Prozona very short. Anterior margin of pronotum truncated, bearing small and weak triangular FM directed more upwards, then forwards. Prozonal and extralateral carinae low, tuberculated, not forming sharp saw-like or fan-like ridge, with small FL1 and more distinct dentiform. FL3 indistinct. Behind FM medial carina extended along the whole length of the pronotum, low, bearing four more or less distinct medial projections of variable size (well visible in lateral view). PM triangular, equal to or larger than FM and joined with the latter as a continuous two-humped structure in specimens of some populations. MM1, large. MM2 is the largest and the most massive projection, usually compressed laterally as a semicircular triangular protuberance. MM3 relatively large, while MM4 almost indistinct, marked by spot and darker than rest of the pronotal disc surface. Unlike in Discotettix species, Disconius shelfordi comb. n. has only one distinct projection from the mediolateral group, MML2, situated in the place where most Tetrigidae (Tetriginae) species have a posthumeral spot. Similar to the previous projections’ group, only one projection exists from the lateral group of the projections. In the metazona the humero-apical carinae forms a moderately sharp humeral angle, projected outwards as a small ML tubercle of the humeral angle, much larger than other tubercles along the margin of the pronotal disc and the lateral lobe; and behind this point the humero-apical carinae is joining the external lateral carinae. The apex of the posterior pronotal process in the dorsal view shallowly excised. The lower part of the lateral lobe with smooth anterior and posterior margins, without smaller teeth. The lateral lobe elongated as spine-like VL, directed exactly outwards, blunt ( Figs 34A, B , 35A, B ).

Wings. The visible part of the tegmen elongated and oval, distinctly acuminate towards the apex, about 2.75 times as long as wide. Hind wings reach the apex of the pronotal process.

Legs. Femora relatively slender, compressed laterally, and finely granulated, with numerous small teeth-like tubercles on the whole surface. Fore and mid femora bearing a hardly noticeable genicular tooth on the knees, and additionally 1–3 small teeth on the dorsal and ventral margin. Hind femur significantly compressed laterally, finely granulated, without any lappets on dorsal and ventral margins, smooth, and not bearing any recognizable outgrowth on the external carinae. Genicular and antegenicular teeth small. Both sides of the dorsal margin of the hind tibia only finely serrated, without any large teeth.

Abdominal apex. Male subgenital plate in ventral view about 1.5 times as long as wide, in lateral view about 2 times as long as tall. Ovipositor elongated.

Observed variability and differences found among populations, with implications for taxonomy. In the different populations of D. shelfordi comb. n., we have observed that the projections of the pronotum differ in size and shape. For example, among the specimens from the banks of the Pajau river the pronotum projections are much more expressed than in the specimens from Kuching (the type locality of the species). This primarily applies to lower and weaker medial protuberances in the specimens from Kuching. Especially FM and PM are quite small and wart-like, MM is medium size and slightly compressed laterally. In specimens from the Pajau river FM and PM are well expressed, and form a continuous double-hump structure. Other MMs are much more expressed, and more compressed laterally, they have semicircular form, especially the largest MM2. Only the examination of a larger series will allow drawing conclusions about the specific value of the aforementioned traits.

Measurements (female syntype and a non-type male). BL ♂ 13.99 mm, ♀ 15.87 mm; PnL ♂ 18.74 mm, ♀ 20.81 mm; PnW ♂ 7.35 mm, ♀ 7.42 mm; AnL ♂ 9.39 mm, ♀ 9.68 mm; TL ♂ 2.43 mm, ♀ 2.62 mm; TW ♂ 0.85 mm, ♀ 0.96 mm; fFL ♂ 3.22 mm, ♀ 3.33 mm; fFW ♂ 0.57 mm, ♀ 0.62 mm; mFL ♂ 4.01 mm, ♀ 4.15 mm; mFW ♂ 0.55 mm, ♀ 0.61 mm; hFL ♂ 7.99 mm, ♀ 8.76 mm; hFW ♂ 2.34 mm, ♀ 2.71 mm; OvL ♀ 1.41 mm; AnL/fFL ♂ 2.91, ♀ 2.9; VW ♂ 1.1 mm, ♀ 1.29 mm; EW ♂ 0.45 mm, ♀ 0.53 mm; VW/EW ♂ 2.44, ♀ 2.43; SW ♂ 0.14 mm, ♀ 0.19 mm; AgW ♂ 0.39 mm, ♀ 0.47 mm; ScW ♂ 0.26 mm, ♀ 0.38 mm; SW/AgW ♂ 0.36, ♀ 0.4; SW/ScW ♂ 0.54, ♀ 0.5; As-L/W ♂ 2.35, ♀ 2.62; PrzW ♂ 3.18 mm, ♀ 3.47 mm; PrzL ♂ 1.5 mm, ♀ 1.71 mm; Prz-W/L ♂ 2.12, ♀ 2.03; TL/TW ♂ 2.86, ♀ 2.73; mFW/TW ♂ 0.65, ♀ 0.64; fFL/fFW ♂ 5.65, ♀ 5.37; mFL/mFW ♂ 7.29, ♀ 6.8; hFL/hFW ♂ 3.41, ♀ 3.23; T1L/T3L ♂ 1.27, ♀ 1.19.

Figures

FIGURE 34. Disconius shelfordi (Hancock, 1907), comb. n., lectotype female from N Borneo: Kuching, in UOMNH. A. dorsal view; B. lateral view; C. head in frontal view; and labels. Photographs by A. Spooner & K. Child. Reproduced with the author's permission. Scale bar = 2 mm.

FIGURE 35. Disconius shelfordi (Hancock, 1907), comb. n., male from N Borneo: Pajau River, in NHRS. A. dorsal view. B. lateral view. C. head in frontal view, and labels. Photographs by Josef Tumbrinck. Scale bar = 2 mm.

FIGURE 36. Adult Disconius shelfordi (Hancock, 1907), comb. n. in the natural habitat. Photograph by Kinmatsu Lin (@ kinmatsu). Reproduced with the author’s permission. Available at the link: inaturalist.org/observations/38326084.