Macromotettixoides parvula Zha & Wen

Zha, Ling-Sheng, Yu, Feng-Ming, Boonmee, Saranyaphat, Eungwanichayapant, Prapassorn D. & Wen, Ting-Chi, 2017, Taxonomy of Macromotettixoides with the description of a new species (Tetrigidae, Metrodorinae), ZooKeys 645, pp. 13-25 : 17-20

Macromotettixoides parvula Zha & Wen sp. n. Figs 1, 2

Diagnosis.

With extremely small size, Macromotettixoides parvula sp. n. can easily be separated from other species of the genus. Other differences are listed in the key to species of Macromotettixoides .

Description.

Female. Body size extremely small.

Head. Face and vertex rough, covered with large and small granules. Vertex nearly at the same level but uneven, 2.0 times as wide as one eye, a little contracted forward, protruding forward and slightly surpassing anterior margin of eyes; anterior margin broadly arcuate and depressed, anterior part of lateral carina distinctly folded upward and reaching top of eyes; medial carina distinct and erected in anterior half, but absent in posterior half; paired fossulae deep, behind fossulae vertex slightly elevated on both sides (Fig. 2b). In lateral view face slightly oblique, fastigium (vertex together with frontal costa) rounded and protruding forward; fascial carinae smooth, between lateral ocelli concave, between antennal grooves widely and obtusely triangular forward (Fig. 2d); in frontal view fascial carinae diverged in the middle of inner margin of eyes, longitudinal furrow wide and shallow and nearly forming into a scutellum, between antennal grooves 1.5 times as wide as diameter of scapus (Fig. 2a). Antenna filiform and short, 17-segmented, inserted decidedly below lower margin of eyes, segment 11 longest, 5.0 times as long as wide (Fig. 2a, d). Eyes globose and protruding, over level of anterior margin of pronotum, lateral ocelli placed at lower one third of inner margin of eyes (Fig. 2a).

Thorax. Pronotum disc very coarse, covered with big and small granules and many thick and net-like wrinkles (Fig. 1). Anterior margin truncated and wide, paired extralateral carinae indistinct (Fig. 2b); pronotum in the center between posterior sulcus and humeral angles slightly elevated, otherwise nearly at the same level. Median carina entire and thick, between sulci distinctly elevated with swollen base, behind humeral angles with a protrusion, the posterior protrusions lower and indistinct; in lateral view upper margin undulate, the first sinusoidal wave occur between sulci, longest and highest, in the middle with a deep concavity, followed by the second wave behind humeral angles, the posterior waves low and nearly at the same height. Prozonal carinae conspicuous, thick, erected and parallel (Fig. 2b); humeral angles obtuse angled and low, pronotum disc behind humeral angles covered with many reticular wrinkles; hind process reaching knees (three males and two females) or barely surpass apex of hind femur (one female), apex sharp-rounded; external lateral carina straight, distinctly surpassing middle of lower margin and reaching two-thirds of hind femur, folded upward indistinctly behind humeral angles; lateral carina of pronotum before apex curved inward; posterior angle of lateral lobe of pronotum extending turning outwards, margin smooth, apex truncated and anterior margin of apex rounded; posterior margin of each lateral lobe with one concavity. Tegmina and wings extremely degenerated, long and oval, apices acute, wing distinctly larger than tegmen, both hidden beneath pronotum and invisible (Fig. 2c). Margins of all femora serrate except base of upper margin of hind femur, upper margins of fore and mid femora nearly straight while lower margins with two teeth (basal and middle) each; hind femur stout, 2.3 times as long as wide, upper margin before antegenicular denticle with a small tooth, other teeth on upper and lower margins indistinct; antegenicular denticle slightly isolated, low, apex or nearly right angled or a little sharp, genicular denticle finger-like, extending backward and apex obtuse; margins of fore and mid tibiae straight; two inner margins of hind tibia serrate, terminal part slightly wider than basal part, outer/inner side with 6-7/4-6 spines; first segment of hind tarsus 1.35 times as long as second plus third, first and second pulvilli small and apices sharp, third pulvillus large and apex obtuse (Fig. 2h).

Abdomen. Ovipositor: upper valva about 4.0 times as long as wide, upper margin arcuate, sub-base widest, in the middle slightly distorted inward, then slightly turn outward and at last inward again; outer margins of upper and lower valvae with saw-like teeth, but base of upper valva smooth (Fig. 2e). Subgenital plate: length nearly equal to width, median carina distinct in anterior part, posterior margin nearly truncated and in the middle triangularly protruding which is slightly folded inward (Fig. 2f).

Coloration. Body dark or dark brown (Fig. 1). Antennae brown, color of terminal 3-5 segments dark, color of the two segments of before and after the longest segment a little light (Fig. 2d). Sometimes both the posterior part of pronotum and the posterior part of outer side of hind femur brown. All tibiae with three yellowish brown rings each, but basal and middle rings of hind tibia large. More or less, infrascapular area, teeth on lower margins of fore and mid femora, upper and lower margin of hind femur, and outer sides of all femora maculated with yellowish brown.

Male. Slightly smaller than female (Fig. 1). Vertex also 2.0 times as wide as one eye; antenna 16 segmented, segment 10 longest. Subgenital plate short cone-shaped, apex nearly truncated, upper apex bifurcate and forming into two obtuse and very short teeth (Fig. 2g). Other characters same as female.

Measurements.

Length of body ♂5.8-6.2 mm, ♀7.5-8.3 mm; length of pronotum ♂5.8-6.0 mm, ♀6.3-7.0 mm; length of hind femur ♂4.1-4.3 mm, ♀4.2-4.5 mm; length of antenna ♂, ♀2.6-2.8 mm.

Type material.

Holotype female, China, Guizhou, Leishan, Leigongshan Mountain, N26°22'18.25", E108°11'28.06", 1430 m alt, 2 Aug. 2016, collected by Lingsheng ZHA. Paratypes: three males and two females, Leigongshan Mountain, 1300-1600 m alt, 1-3 Aug. 2016, collected by Lingsheng ZHA.

Ecology and habits.

Specimens of Macromotettixoides parvula sp. n. were collected and observed among low and sparse shrubs with fall-leaf layers in gullies, slopes and a dry stream bed in humid rainforests of Karst Region (Fig. 3). They are very small and not easy to find; they move quickly and they like to jump into shrubs when being disturbed. They mainly feed on humus. We infer their adults may prefer to stay in sandy soil, because body surfaces of most specimens are covered tightly by sandy soil ( Zha et al. 2016a, fig. 1a, b).

Etymology.

The new species epithet ' parvula ' means body size is extremely small.

Distribution.

China (Guizhou). Only found in Leigongshan Mountain (Leishan County).