Research Article |
Corresponding author: Maoyin Sheng ( shmoy@163.com ) Academic editor: Fernando Montealegre-Z
© 2016 Ling-Sheng Zha, Maoyin Sheng, Tingchi Wen, Kevin Hyde.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Zha L-S, Sheng M-Y, Wen T-C, Hyde KD (2016) A new species and a revised key of the genus Thoradonta (Orthoptera, Tetrigidae). ZooKeys 607: 69-79. https://doi.org/10.3897/zookeys.607.9056
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A new species of the genus Thoradonta (Orthoptera, Tetrigidae), Thoradonta varispina Zha & Sheng, sp. n., was found in Lengshuihe Nature Preserve, Jinsha, Guizhou, China. It is introduced with a description and photographs and compared with similar taxa. Ecology, habits, and morphological variation of the new species are discussed and illustrated. Generic characteristics of Thoradonta are updated and an updated key to all known species of Thoradonta is given.
Ecology, habits, morphological variation, Scelimeninae , taxonomy
The genus Thoradonta Hancock belongs to Scelimeninae, Tetrigidae, type species Thoradonta dentata Hancock. To date it includes 21 known species worldwide, distributed in subtropical and tropical Asia (China, Bengal, Hong Kong, India, Indonesia, Malaysia, Myanmar, Nepal, Singapore, Sri Lanka, the Philippines, and Vietnam) and equinoctial Africa (
During investigation of species diversity in Lengshuihe Nature Preserve, Jinsha County, Guizhou Province, China during 3–10 Aug 2015, a new species of the genus Thoradonta was found, Thoradonta varispina Zha & Sheng, sp. n. A description and illustrations introduce the species, and it is compared with similar taxa. Ecology, habits, and morphological variation of body structure of the genus Thoradonta are discussed. Generic characteristics of Thoradonta are updated and an updated key to all known species of the genus is given.
Specimens were photographed using a stereomicroscope (Keyence VHX-1000). Morphological terminology and measurement landmarks follow
Thoradonta varispina sp. n. is distinguished from T. obtusilobata Zheng, 1996 by the following characters: 1) vertex 1.8–2.0 times as wide as one eye (width of the widest part of an eye in dorsal view); 2) midkeel of pronotum not reaching anterior margin of pronotum; 3) upper margin of hind femur before antegenicular denticle with a small protrusion only, but not forms into 2–3 lamellae; 4) lower margin of hind femur entire, without protrusion; 5) third pulvillus of first segment of hind tarsus distinctly longer than first and second.
Female. Body size small, covered with numerous small granules and many nodules.
Head. Head not protruding over level of pronotal surface; vertex 1.8-2.0 times as wide as one eye, anterior margin straight, protruding but not surpassing anterior margins of eyes, lateral margins folded upwards but not surpassing top of eyes; median carina conspicuous and protruding in anterior half which is visible before eyes in profile, while obscure or absent in posterior half; vertex together with frontal ridge arcuate and protruding, distinctly concave between lateral ocelli, then strongly arched and protruding between antennae, longitudinal furrow between antennae slightly wider than diameter of first segment of antenna, margins of longitudinal furrow finely serrate. Antenna filiform, 17-segmented, inserted slightly below lower margins of eyes, length of longest segment (segment IV, male in VIII) 4.5 times its width. Eyes globose, protruding but not above level of pronotum; lateral ocellus situated slightly below middle of anterior margin of eye.
Thorax. Pronotum very coarse, covered with numerous small granules and many nodules; middle of anterior margin little concave; lateral keels of prozona erected, distal part higher than basal part, slightly contracted backward, sometimes distal part excessively contracted inward. Midkeel not reaching anterior margin of pronotum, otherwise nearly entire, in profile upper margin of pronotum distinctly undulate with wave peaks becoming lower backward. These sinusoidal waves lamellate and erected, first highest, with intumesced base, both sides of intumescence with a pair of big nodules at margins of pronotum; second lamella longest and undulate, on both sides pronotal disc distinctly concave followed by a pair of long oblique nodules, and lateral margins of pronotum distinctly folded upwards; the latter midkeel with 4–5 lamellae of intumesced base. Humeral angle obtusely angled; a pair of abbreviated carinae present between shoulders, slightly contracted forwards; pronotum slightly uplifted between shoulders; hind process of pronotum long cone-shaped, reaching (few specimens) or slightly surpassing (most specimens) apex hind femora, distal part slightly down-curved and apex sharp. Posterior angles of lateral lobes of pronotum laminate and expanded and extending outwards, apex varies distinctly in different individuals: upper lobe not produced, slightly produced or triangularly laterally produced; subtruncate behind which is margined with fine teeth (Fig.
Abdomen. Ovipositor: upper valvulae 3.3 times as long as wide, outer margins of upper and lower valvulae with saw-like teeth. Posterior margin of subgenital plate: narrowing backward; middle triangularly protruding, sometimes this protrusion folded inward, forming a basal concavity and a protrusion on both sides (Fig.
Coloration. Body dark brown. Antenna brown, distal segments darker than basal segments; hind wings black; for and mid femora and tibiae with 3 yellowish brown bands each, bands of all femora obscure; lower outside of hind femur black, center of inner side of hind femur dark brown; hind tibia with 2 long yellowish brown bands.
Male. Body size slightly smaller than female. Antenna 16-segmented. Fore femur nearly the same as that of female; mid femur distinctly wider than fore femur and visible part of tegmen, narrowing from basal to distal side, and basal part thicker than distal part. Subgenital plate short cone-shaped, apex bifurcate but not bidentate.
Length of body ♂6.2–7.8 mm, ♀7.5–9.0 mm; length of pronotum ♂6.1–7.0 mm, ♀7.5–8.7 mm; length of hind femur ♂3.5–4.2 mm, ♀4.7–5.4 mm.
Holotype female, China, Guizhou, Jinsha County, Lengshuihe Natural Reserve, N27°54', E106°00', 650 m alt, 7 Aug. 2015, collected by Ling-Sheng ZHA. Paratypes: 27 males and 19 females, 500–800 m alt, 5–9 Aug. 2015, other data same as holotype.
Thoradonta varispina sp. n.: a frontal view of female head b dorsal view of female head and anterior part of pronotum c lateral view of female head and anterior area of pronotum d ventral view of female subgenital plate e lateral view of female ovipositor f laterial view of male subgenital plate g posterior view of male subgenital plate. Scale bars a–c: 1.0 mm, d–g: 0.5 mm.
All specimens of the new species were collected in humid, sandy, and stony environments alongside streams (Fig.
This new species epithet means spine of upper lobe of posterior angle of lateral lobe of pronotum varies in different individuals.
China (Guizhou).
1 | Tegmen and wing invisible. Indonesia | T. butlini Blackith & Blackith |
– | Tegmina and wings visible | 2 |
2 | Upper lobe of posterior angle of lateral lobe of pronotum not produced or slightly produced, not spinose (Fig. |
3 |
– | Upper lobe of posterior angle of lateral lobe of pronotum produced conspicuously and spinose (Fig. |
5 |
3 | Body length 10.79–12.81 mm; hind process of pronotum distinctly surpassing apex of hind femur (Fig. |
T. aspinosa Ingrisch |
– | Body length 6.0–9.0 mm; hind process of pronotum shorter, only reaching or slightly surpassing apex of hind femur (Fig. |
4 |
4 | Vertex 1.5 times as wide as one eye; midkeel of pronotum reaching anterior margin of pronotum; upper margin of hind femur before antegenicular denticle with 2–3 lamellate protrusions, lower margin with a distinct protrusion. China | T. obtusilobata Zheng |
– | Vertex 1.8–2.0 times as wide as one eye; midkeel of pronotum not reaching anterior margin of pronotum; upper margin of hind femur before antegenicular denticle with a small protrusion only, lower margin without protrusion. China | T. varispina sp. n. |
5 | Hind process of pronotum shorter, not reaching or reaching apex of hind femur (Fig. |
6 |
– | Hind process of pronotum longer, surpassing apex of hind femur (Fig. |
9 |
6 | Hind process reaching apex of hind femur (Fig. |
T. bengalensis Shishodia |
– | Hind process not reaching apex of hind femur (Fig. |
7 |
7 | Wings shorter, not reaching apex of hind process; third pulvillus of first segment of hind tarsus longer than second (Fig. |
T. nodulosa (Stål) |
– | Wings longer, reaching apex of hind process; third pulvillus of first segment of hind tarsus equal to second in length | 8 |
8 | Upper lobe of posterior angle of lateral lobe of pronotum obliquely dentate (Fig. |
T. dentata Hancock |
– | Upper lobe of posterior angle of lateral lobe of pronotum acutely spinose, pointing laterally (Fig. |
T. spinata Hancock |
9 | Body size stout; hind process of pronotum surpassing slightly beyond apex of hind femur (Fig. |
10 |
– | Body size slender; hind process of pronotum surpassing far beyond apex of hind femur (Fig. |
13 |
10 | Anterior margin of vertex nearly as wide as posterior margin; spine of upper lobe of posterior angle of lateral lobe of pronotum pointing distinctly obliquely backward (Fig. |
T. yunnana Zheng |
– | Anterior margin of vertex distinctly narrower than posterior margin; spine of upper lobe of posterior angle of lateral lobe of pronotum pointing laterally or slightly obliquely backward | 11 |
11 | Spine very long (Fig. |
T. longispina Zheng & Xie |
– | Spine shorter (Fig. |
12 |
12 | Antenna inserted at the level of lower margins of eyes, the longest segment 4.0 times as long as wide; first segment of hind tarsus 1.75 times as long as third. China, India | T. spiculoba Hancock |
– | Antenna inserted decidedly below lower margins of eyes, the longest segment 6 times as long as wide; first segment of hind tarsus 1.3–1.4 times as long as third. Thailand | T. spiculobaoides Zha & Kang |
13 | Spine of upper lobe of posterior angle of lateral lobe of pronotum pointing laterally (Fig. |
14 |
– | Spine of upper lobe of posterior angle of lateral lobe of pronotum pointing obliquely backward (Fig. |
16 |
14 | Vertex 2.0 times as wide as one eye; wings not reaching apex of hind process (Figs |
T. centropleura Podgornaya |
– | Vertex not more than 1.5 times as wide as one eye; wings reaching or surpassing apex of hind process | 15 |
15 | Spine slender and longer (Fig. |
T. longipenna Zheng & Liang |
– | Spine shorter (Fig. |
T. transspicula Zheng |
16 | Vertex wider, 1.5–2.0 times as wide as one eye (Fig. |
17 |
– | Vertex narrower, 1.18–1.35 times as wide as one eye | 21 |
17 | Wings longer, surpassing far beyond apex of hind process; disc of pronotum black. China | T. nigrodorsalis Zheng & Liang |
– | Wings shorter, not reaching or surpassing slightly beyond apex of hind process; pronotum and body in the same color | 18 |
18 | Pronotum not less than 5.0 times as long as posterior part of hind process which is beyond apex of hind femur | 19 |
– | Pronotum not more than 4.0 times as long as posterior part of hind process which is beyond apex of hind femur | 20 |
19 | Lateral keels of prozona parallel; wings not reaching apex of hind process. China | T. lancangensis Zheng |
– | Lateral keels of pronoza distinctly contracted backward; wings surpassing apex of hind process. China | T. dianguiensis Deng, Zheng & Wei |
20 | Antenna inserted between lower margins of eyes; lateral keels of pronoza parallel; humeral angle widely rounded. China, India | T. lativertex Günther |
– | Antenna inserted decidedly below lower margins of eyes; lateral keels of pronoza distinctly contracted backward; humeral angle obtusely angled. Thailand | T. lativertexoides Zha & Kang |
21 | Vertex 1.25–1.35 times as wide as one eye; body surface smooth; length of posterior part of hind process which is beyond apex of hind femur 3.0–3.4 mm (Fig. |
T. palawanica Günther |
– | Vertex nearly as wide as one eye; body surface coarse; length of posterior part of hind process which is beyond apex of hind femur 1.5-2.0 mm (Fig. |
T. apiculata Hancock |
Species of the genus Thoradonta generally live in humid and sandy places near streams, rivers, or ponds. They move frequently in sunshine, and they generally feed on mosses, algae, lichens and all sorts of humus. Though provided with developed hind wings they seldom really fly, instead their hind femora are well-developed, suitable for jumping when disturbed. Colors of their bodies are generally adapted to the soil of their habitats. Apart from generally coarse an uneven, body surfaces of most individuals were often tightly covered by numerous sand grains. We infer that they lay eggs in sandy soil, and most of their life time they may conceal their body in sandy soil (
According to T. varispina sp. n., and comparing with descriptions of 21 known species of the genus Thoradonta (
Body size small. Vertex equal to or wider than one eye, frontal ridge distinctly protruding forward between antennae. Antenna filiform, inserted between or below lower anterior margins of eyes. Eyes globular and prominent, lateral ocellus situated in or slightly below middle of anterior margin of eye. Distal segments of maxillary palpus slightly compressed. Pronotal disc generally covered with many nodules; midkeel undulate, partially lamellate and erected before shoulders; pronotum slightly uplifted between shoulders; a pair of abbreviated carinae present between shoulders; lateral margins of pronotum behind humeral angles folded upwards; hind process of pronotum wedge-shaped, not reaching, reaching or surpassing apex of hind femur; posterior angle of lateral lobe of pronotum laminate and expanded and extending outwards, apex varies conspicuously: 1) upper lobe generally produced, spinose or acutely angled, extending laterally or obliquely backward; 2) lower lobe generally truncate, sometimes also produced and obtusely angled or acutely angled; 3) both upper and lower lobes not produced or produced inconspicuously, and apex truncate or subtruncate. Visible part of tegmina ovate, hind wing normal but invisible in T. butlini. First segment of hind tarsus generally longer than third.
This work was supported by the Guizhou R&D Programs for Social Development (Qiankehe SY[2015]3052 and SZ[2014]3036) and the Guizhou Science and Technology Cooperation Program (Qiankehe LH Zi [2015] No. 7779).