Betiscoides muris, Matenaar, 2024

Matenaar, Daniela, 2024, Application of extended depth of field 3 D imagery to tackle the challenges of cryptic species: a use case in the genus Betiscoides Sjoestedt, 1924 (Orthoptera, Caelifera, Lentulidae) and its taxonomic implications, Evolutionary Systematics 8 (1), pp. 65-90 : 65

Betiscoides muris sp. nov.

Type material.

The type material is deposited in the invertebrate collection of Hessisches Landesmuseum Darmstadt (HLMD). Holotype. Male, pinned, HLMD-Cael-364HT, B156, (Genbank Acc. PP411598, PP417668), South Africa, Western Cape province, Groot Winterhoek Wilderness Area, 32°59'21.52"S, 19°3'26.84"E, 991 m above sea level, Plot 134, Restio wetland, 18 April 2016, leg. D. Matenaar.

Paratypes. Allotype. Female, pinned. HLMD-Cael-368AT, B155, South Africa, Western Cape, Groot Winterhoek Wilderness Area, 32°59'53.06"S, 19°4'12.40"E, 929 m above sea level, Plot 133, Restio wetland, 18 April 2016, D. Matenaar. Paratypes. HLMD-Cael-362PT, B153; HLMD-Cael-366PT, South Africa, Western Cape, Groot Winterhoek Wilderness Area 32°59'35.34"S, 19°3'32.90"E, 969 m above sea level, Plot 65, Restio wetland, 18 April 2016, D. Matenaar. HLMD-Cael-363PT; HLMD-Cael-367PT, B154, South Africa, Western Cape, Groot Winterhoek Wilderness Area, 32°58'54.76"S, 19°3'18.37"E, 1001 m above sea level Plot: 66, Restio wetland, 18 April 2016, D. Matenaar. HLMD-Cael-365PT South Africa, Western Cape, Groot Winterhoek Wilderness Area, 32°59'53.06"S, 19°4'12.40"E, 929 m above sea level, Plot 133, Restio wetland, 18 April 2016, D. Matenaar. HLMD-Cael-360PT, HLMD-Cael-361PT; HLMD-Cael-369PT, South Africa, Western Cape, Groot Winterhoek Wilderness Area, 134: 32°59'21.52"S, 19°3'26.84"E, 991 m above sea level, Plot 134, Restio wetland, 18 April 2016, D. Matenaar. HLMD-Cael-379PT, B169, South Africa, Western Cape, Groot Winterhoek Wilderness Area, Restio wetland 33°0'11.81"S, 19°4'20.91"E, 908 m above sea level, Plot 95, Restio wetland, 06 March 2020, D. Matenaar. In total, five female and five male paratypes are designated.

Etymology.

The specific epithet is a Latin noun, meaning mouse. It refers to the species’ very slender and delicate habitus.

Definition.

The described species is assigned to the genus Betiscoides Sjöstedt, 1924 due to phylogenetic and overall morphological characteristics. The very slender, elongate, stick-like and medium sized body defines the species. The antennae are ensiform and triangular in cross-section. The head is acutely conical elongated and the end of the abdomen shows dense and long hairs. The arolium is large. The subgenital plate is elongate and acutely conical; the ovipositor is short with well-curved valves and sharp tips.

Diagnosis.

This new species differs morphologically from the described ones mostly by its overall delicate habitus, the comparatively densly and longhaired end of the abdomen of the males. The body is smaller and more delicate than Betiscoides meridionalis . The head is more elongate than in B. nova and B. parva . The genital valves are strongly acute, sharply pointed, upper valve width narrower than in Betiscoides meridionalis . Just as B. nova , the new species represents a divergent evolutionary lineage as stated in Matenaar et al. (2018) being most closely related to B. parva (p-distance: 0.0734). As Key (1937) stated for B. parva and B. sjostedti , also this species is far less elongate than Betiscoides meridionalis , and B. parva , B. nova and B. sjostedti as well as B. muris are morphologically more similar to each other than any of these to B. meridionalis. Morphologically B. muris relates the most to B. sjostedti although B. sjostedti lacks the hairy end of the abdomen, which instead can be found even stronger in B. parva (Fig. 15 ). The genetic distance of B. muris to B. meridionalis is closer than to B. nova or B. sjostedti . The frontal ridge of the new species is more prominent and protruding than in B. nova ; Fig. 16 .

Description of the holotype.

Body of medium length, slender, delicate (Figs 9B , 10B ). BL 22.5 mm. Integument finely rugose, shiny golden. Antennae 22-jointed, ~ 6 mm, finely ensiform, slightly flattened above and slightly tapering, finely pointed and shiny, evenly punctured, in length longer than the head, reaching the pronotum. Left antenna between the 12th and 13th and on the 15th segment marked with shiny orange fluid-like spot. Head elongate, conical, from above almost 4 times as long as its width at the occiput and twice the diagonal length than the height, HL 3.8 mm, HDL 5.52 mm, HH 2.59 mm. Fv 1.4 mm, 0.7 the length of an eye, angular, the margins well raised but obtuse-angled, narrowing from the anterior margin of the eye forwards; callus line above the eyes culminating into the margins of Fv, (straight), strongly protruding in front of the eyes; median carinula faintly discernible on the fastigium. Head in profile convex above, face slightly incurved; angle acute (app. 49.4°). Apex of fastigium in profile slightly raised culminating dot-like at the very apex; frons oblique. Fr between the antennae in profile somewhat projecting, thin, lamelliform, lateral carinae distinct, below the antennae very narrow, shallowly sulcate, crossing the sulcus and only close to the clepeus at the basal part obliterated. Fc straight, distinct throughout. Eyes oval, 1 ¾ as long as their maximum width, their surface strongly convex, both margins somewhat curved, the upper more so than the lower, upper and lower margin slightly raised, as of callus. Ratio of eye length to fastigium length 0.61. PL 2.6 mm, lateral ventral length 1.78 mm, pronotum cylindrical, with weak median and indistinct lateral carinae; no sulcus crossing dorsum. Hind margin of metazona very slightly concave, anterior margin straight; sides of pronotum with the lower margin straight, anterior lower angle slightly more than 90°, rounded; posterior lower angle 90°, rounded. Pp destroyed through pinning. Mesosternal interspace reduced with mesosternal lobes connected. Anterior and middle legs strongly shortened. Tibia and tarsi haired, tarsi with black claws. Hind legs reaching beyond the end of abdomen. HFL 8.1 mm, hind femora very slender, about 5.5 times as long as their maximum width; outer apex of knees acute; hind tibiae with 10 outer and 13 inner spines. External apical spine of hind tibia present. Hind tarsus shorter than half of the length of the tibia. Arolium extremely large, its margin of beige color. Male supra-anal plate elongate, acutely angular. Cerci short, conical. Subgenital plate strongly elongate, 2.85 mm, acutely conical, 35.8°. End of abdomen with dense but fine, comparatively long hairs, see Fig. 15A . Supra-anal plate with the basal part about 0.65 the length of the apical part, the longitudinal depression distinct; the apical part of the plate shaped like an equilateral triangle with the base curved and the sides straight; apical angle widely rounded; no depression on the apical angle. Subgenital plate about twice the length of the supra-anal plate; comparatively sharply pointed; lower margin convex, upper margin straight; apex acute. Genital apparatus about 3.5 the length of one tergit. SGP: 2.85 mm, last three tergits: 2.32 mm ratio: 1.22. The total body volume is 5.38305e-08 m3. The volume of the visible part of the eye is 587729028.76 µm 3. The longitudinal height being 493.28 µm, and the length 2137.79 µm. The cross-sectional height is 483.82 µm and the width itself is 1213.70 µm. General coloration dark-brown. Antennae, fore and middle legs and knees are slightly paler than the brown primary color of the body. The upper part of the head, thorax and abdomen, within the callus line, is beige. The Fv is dark brown almost black. A longitudinal stripe extends from the front of the head backwards along the central ridge of the body. The lateral stripe backwards from the base of the eye is beige-pink. It starts at the lower hind corner of the eye (as a somewhat raised callus ridge) and reaches the end of the middle leg. Eyes brown, hind femora of brown color processing into yellow beneath, knees, upper and lower external carina of the hind femur yellow. Hind tibia orange and brown in the lower side, spines and spurs black-tipped.

Description of the allotype.

Larger than the male (Fig. 16I ). BL 26.5 mm, antennae 22-jointed, ~ 5 mm. fastigium about as long as an eye. The anterior and posterior margin of the eye are somewhat raised, as of torus. HL 4.3 mm, HDL 5.89 mm, HH 2.92, head in profile acute-angled (50.9°). PL 3 mm, sides of pronotum with lower margin straight; anterior margin sloping forward, only very slightly incurved, posterior margin very little incurved, sloping forward in the upper part. Anterior lower angle more than 90°, posterior lower angle 90°, both rounded. Pp T-shape, proximal concave, 673.43 µm in length, anterior part 233.54 µm width and 52.87 µm higher than the posterior part (of 122.29 µm width, see Figs 17 , 18 ), fine and thin hairs on the broader anterior part and at the sides only. HFL 9 mm, hind tibiae with 10 outer spines, 11 inner spines. Protrusion of lower genital valves crossed by two diagonal sulci. Pr lines 1 and 2 slightly curved, bending inwards, apex of Pr thereby rounded although degree of protrusion strongly acute (79°), Pr line 1 slightly longer (155 µm) than Pr line 2 (91 µm), Pr distance is 199 µm, Pr area is of 12455.69 µm 2 and protrusion vertical distance is 129.66 µm, protrusion to tip of valve distance (horizontal distance) is 330.13 µm (see Fig. 13B ). Tips of the valves black and strongly acute. End of upper valve slender and acute pointed, of 134°, upper valve distance 173 µm, upper valve width is 173 µm. General coloration similar to, but slightly less dark, than that of the male. Eyes and hind femora, both outside and inside, paler than the rest of the body; outer side of femur with black stripe and fishbone pattern; hind tibiae darker than the femur but without gradient in color. The volume of the visible part of the eye is 1356324476.51 µm 3. With longitudinal height being 760.13 µm, and the length 2131.68 µm. The cross-sectional height is 696.96 µm and the width itself is 1175.43 µm.

Variation.

The antennae are 22-23-jointed and the segments are covered with fine, black dots and shiny appearance in all specimens. Posterior margins of the antennae segments of one male specimen are matt beige, while the rest is of the usual common shiny brown color. Specimens show little differences in the shape of the head in profile, varying from described morphology of the holotype to a slightly more concave form. Similar to B. nova , the face varies concerning the degree of distinction of the lateral carinae below the sulcus and the shape of the sulcus itself. In some specimens, the lateral carinae are distinct throughout, also beneath the sulcus. The sulcus is shaped as a mustache sometimes. This intraspecific variation is not sex-specific. Variation in spines on the hind tibia: In male, the hind tibiae had 9-10 outer and 10-14 (!) inner spines. In females, the hind tibia showed 9-10 outer spines and 11-13 inner spines. In contrast to the other known species of Betiscoides , there seems to be a intraspecific variability in the shape of the prosternal process, in general the Pp is about twice as long as broad, its margins and angles rounded; the anterior end little broader than the posterior. However, four different shapes can be distinguished within the B. muris species, making the Pp itself a variable character within this species (see Fig. 17 ): a) thin lamelliform (one thin line from above), b) trapezoid, c) T-Shape, d) thick lamelliform. Furthermore, the trapezoid and thick lamelliform Pps are often tuberculate and hairy, whereas T-shape and thin lamelliform ones are rather smooth and not very rugose. The 3D image analysis revealed variations in the elevation of the prosternal process. In some specimens, the anterior part is higher than the posterior and vice versa (see Figs 18 , 19 ). The Pp of specimen HLMD-Cael-379PT, B169 is 541 µm long and the posterior part is 167.91 µm higher than the anterior; the Pp of specimen HLMD-Cael-367PT, B154 is 614.53 µm long and the posterior part is 148.39 µm higher than the anterior. General coloration in males dark-brown. Antennae, fore and middle legs are of the same brown primary color as the body. The upper part of the head, thorax and abdomen, within the callus line, is of light brown, orange or yellow color. The lateral stripe backwards from the base of the eye is beige. It starts at the lower hind corner of the eye (as a somewhat raised callus ridge) and stops right behind the middle leg. In one male, the stripe seems to extend to the femur as a yellow line. Eyes brown, hind femora pale, especially when light brown within the callus line, or with blueish line. In life, sometimes of green color (Fig. 20 ). Knees light brown. Hind tibiae brown, spines and spurs black-tipped. Female: General primary coloration similar to that of the male. No variation toward green or light brown color within the callus line. Hind femora, both outside and inside, paler than the rest of the body, varying in one female towards blue, femoral stripe often present, herring bone pattern distinct hind tibiae brown. Detailed measurements are provided in Table 1 .

Specimen HLMD-Cael-379PT, B169 is not included in the subgenital plate degree measurement due to damage.

Distribution, ecology and conservation status.

Described from six males and five females from Groot Winterhoek, Western Cape, South Africa, collected in 2016 and 2020. The species occurs on the plateau of the Groot Winterhoek Nature reserve in restio-dominated wetland. It is abundant in patches with water covering the bare ground between the single restio plants. As the three formally recognized species of Betiscoides are considered “endangered” ( Hochkirch 2012a, 2012b, 2012c), I propose this status as well for B. muris as this species is only known to occur at a single locality and its habitat is in decline.

Figures

Figure 9. Holotypes of Betiscoides nova sp. nov. and Betiscoides muris sp. nov. in lateral view. A. Shows B. nova, HLMD-Cael- 4 HT, B 168; B. Shows B. muris, HLMD-Cael- 364 HT, B 156.

Figure 10. Holotypes of Betiscoides nova sp. nov. and Betiscoides muris sp. nov. in dorsal view. A. Shows B. nova, HLMD-Cael- 4 HT, B 168; B. Shows B. muris, HLMD-Cael- 364 HT, B 156.

Figure 13. Ovipositor valves, lateral view. A. Allotype of B. nova sp. nov. HLMD-Cael- 18 AT, B 166; B. Allotype of B. muris sp. nov. HLMD-Cael- 368 AT, B 155.

Figure 15. Images of the end of the abdomen of specimens A. HLMD-Cael- 364 HT, B 156 (Betiscoides. muris sp. nov.); B. HLMD-Cael- 4 HT, B 168 (B. nova sp. nov.); C. B. parva (HLMD-Cael- 381, B 103) and D. B. sjostedti (HLMD-Cael- 382, B 21).

Figure 16. Lateral views of female and male type specimens B. muris sp. nov. A-D. HLMD-Cael- 360 - 363 PT; E. HLMD-Cael- 364 HT, B 156; F-H. HLMD-Cael- 365 - 367 PT; I. HLMD-Cael- 368 AT, B 155; J. HLMD-Cael- 369 PT.

Figure 17. High resolution DOF images of the prosternal process of Betiscoides muris sp. nov. clustering in DEL 22, Groot Winterhoek, revealing four different shapes of Pp. A. Image of HLMD-Cael- 379 PT, B 169; B. Image of HLMD-Cael- 366 PT; C. Image of allotpye HLMD-Cael- 368 AT, B 155; D. Image of HLMD-Cael- 367 PT, B 154.

Figure 18. 3 D-image of the prosternal process of the allotype of Betiscoides muris sp. nov. HLMD-Cael- 368 AT, B 155. The output of the 3 D profile image analysis is shown, including the curve progression from the anterior to the posterior part in profile, and total length and height.

Figure 19. 3 D image of the prosternal process of B. muris sp. nov. specimen HLMD-Cael- 379 PT, B 169. The output of the 3 D profile image analysis is shown, including the curve progression from the anterior to the posterior part in profile, and total length and height.

Figure 20. Male individual of Betiscoides muris sp. nov. from Groot Winterhoek Wilderness Area, South Africa in life; image taken on 06 March 2020, 32 ° 58 ' 54.76 " S, 19 ° 3 ' 18.37 " E.