Svistella yayun He, 2024

Hou, Jing-Wen, Xu, Yue, Hu, Tian-Hao, Zhang, Zi-Heng, Wu, Shi-Yang, Gong, Pu & He, Zhu-Qing, 2024, A new species of Svistella Gorochov, 1987 from Xizang, China (Orthoptera, Trigonidiidae, Trigonidiinae), ZooKeys 1193, pp. 145-160 : 145

Svistella yayun He sp. nov.

Figs 1A, B , 2A-E , 3A-F , 4D-F

Diagnosis.

The new species is characterized as follows: small to medium body size for the genus; dark-brown setae on the 5th segment of maxillary palp; small, inner tympanum; hind femora without black stripe; tegmina unicolor. It is morphologically similar to S. rufonotata but differs in having dark-brown setae on the 5th segment of maxillary palp (Fig. 4A-F ), an ectoparamere with rounded corner (Fig. 5A-C ), and a smaller inner tympanum (Fig. 5D-G ).

Materials examined.

Holotype: China • ♂; Xizang, Zayu ; 28°28.20'N, 97°01.22'E; 1565 m); 9 July 2023; He Zhu-Qing leg.; ECNU 4969 . Paratypes: 2♂, ECNU 4961, ECNU 4970 & 2♀, ECNU 4967, ECNU 4968; same data as for holotype .

Description.

Male. Body size small. Head slightly wider than anterior margin of pronotum, occiput slightly convex (Figs 1A , 2A ); frontal rostrum about as wide as first antennal segment, with two rows of setae extending to vertex (Fig. 2C ); vertex not dorsally flattened; antennae long and pubescent; compound eyes slightly protruding forwards; 5th segment of maxillary palpi triangular and swollen (Fig. 2D ). Pronotum with setae, posterior margin widened; fore tibiae armed with two oval tympanums, with outer one bigger than inner one (Fig. 3A, B ); hind tibiae bearing three pairs of dorsal spurs (Fig. 3C ) and five apical spurs (two internal ones distinctly longer and three external ones shorter); tegmina barely reaching apex of abdomen. Cercus with long, thin hair.

Genitalia. Pseudepiphallus separated into two lateral parts joined by a straight sclerotized bridge. Pseudepiphallic lophi curved inwards with 3 or 4 forks apically. Posterior marginal area of endoparameron with minute teeth and short setae (Fig. 3E, F ).

Female. Similar to male (Fig. 1B ). Tegmina slightly convex and not extending to abdominal apex (Fig. 2B ). Ovipositor long and curved upwards, finely denticulate on dorsal and ventral sides (Fig. 2E ).

Coloration. Body brown; legs yellowish brown. Head orange and marked with five vertical red stripes extending to pronotum in dorsal view. Setae on the 5th segment of maxillary palpi dark brown (Fig. 4D, E ). Abdomen with 1 lateral red spot on both sides of each abdominal segment in female. Each hind femur with a dark-brown stripe near knees when alive (Fig. 1A, B ) but disappearing after drying (Fig. 3D ). Ovipositor dark brown; apical half darker than basal part.

Variation. A paratype (ECNU 4961) has seven dorsal spurs on the hind tibiae (four internal ones and three external ones), while all the other examined specimens bear six dorsal spurs on the hind tibiae.

Measurements.

Holotype: ♂ BL 5.63, PL 1.09, FWL 4.08, HFL 4.35; Paratypes: ♂ BL 5.86-6.16, PL 1.05-1.18, FWL 4.09-4.14, HFL 4.07-4.30; ♀ BL 5.55-5.63, PL 1.19-1.27, FWL 3.36-3.41, HFL 4.19-4.30, OL 2.05-2.07.

Distribution.

China (Xizang).

Etymology.

The specific epithet yayun is for the Chinese phonetic alphabet, 雅韵, which means "beautiful music".

Molecular study

In total, 39 COI sequences including our newly described S. yayun He, sp. nov., as well as the COI sequence of Amusurgus genji as the outgroup, were obtained. The results of the two molecular methods identified 11 putative species, which largely conform to the distance tree inferred from the NJ topology and are all consistent with separating S. yayun He, sp. nov. as a species (Fig. 6 ).

Song analysis

The calling song of Svistella yayun sp. nov. is stereotyped with 37.11 ± 5.00 [30-42] echemes/minute. Each echeme continues 0.966 ± 0.049 [0.901-1.094] second and consists of 19.77 ± 1.060 [18-24] syllables (Fig. 7 ). The peak frequency is 5332.420-5594.540 Hz (Fig. 7 ). Although S. rufonotata and S. yayun are similar morphologically, they can be distinguished by their songs. The characteristics of the songs of all included species in PCA are shown in Table 1 . The species S. fallax was not included in PCA, because the audio file was lost, and the peak frequency for this species was unavailable.

PCA results are shown in Fig. 8 . The extracted components PC1 eigenvectors accounted for 57.90% of the variance, PC2 for 24.04%, PC3 for 15.05%, PC4 for 2.02%, and PC5 for 0.99%. Except for S. wuyong and S. malu , the remaining species can be clearly identified via the analysis of their calling songs.

Other materials examined

Svistella rufonotata : China • ♂; bought from Flowers-birds Market; September 2016; He Zhu-Qing; ECNU 266 • ♂; Yunnan, Mengla, Wangtianshu (望天树景区); 21°37.04'N, 101°33.56'E; 26 April 2017; He Zhu-Qing leg.; ECNU 494 • ♂; Hainan, Baisha, Nankai; 19°04.78'N, 109°22.57'E; 18 March 2019; He Zhu-Qing leg.; ECNU 1634 • ♂; Fujian, Wuyishan; 27°41.28'N, 117°44.38'E; 22 September 2018; He Zhu-Qing leg.; ECNU 1756.

Figures

Figure 1. Living Svistella yayun He, sp. nov. A male B female.

Figure 2. Svistella yayun He, sp. nov., male holotype, ECNU 4969, and female paratype, ECNU 4968 A habitus of male B habitus of female C male head and pronotum in dorsal view D male face in front view E female ovipositor in lateral view. Scale bars: 1 mm.

Figure 3. Svistella yayun He, sp. nov. A outer side of fore tibiae B inner side of fore tibia C hind tibiae in dorsal view D hind femora in lateral view E male genitalia in dorsal view F male genitalia in ventral view. All images are from holotype, ECNU 4969. Scale bars: 1 mm.

Figure 4. The 5 th segment of left maxillary palp of Svistella rufonotata (A-C) and S. yayun He, sp. nov. (D, E) images A-C from specimens ECNU 494, ECNU 1634, and ECNU 1756, respectively D-F from paratypes ECNU 4961, ECNU 4967, and holotype ECNU 4969, respectively. Scale bars: 250 μm.

Figure 5. Male genitalia and right inner tympanum of Svistella rufonotata and S. yayun He, sp. nov. A male genitalia of S. yayun He, sp. nov. in ventral view, holotype, ECNU 4969 B, C male genitalia of S. rufonotata in ventral view from specimens ECNU 266 and ECNU 494, respectively D, E inner tympanum of S. yayun He, sp. nov. from a paratype ECNU 4961 and the holotype, ECNU 4969, respectively F, G inner tympanum of S. rufonotata from specimens ECNU 494 and ECNU 1756, respectively. Black arrows indicate the tip and a lateral process of ectoparamere. Scale bars: 0.5 mm.

Figure 6. Distance tree of Svistella species based on COI genes. Rooted by Amusurgus genji, the tree was constructed using the neighbor-joining (NJ) method with the Kimura 2 - parameter model and a 0.19 gamma parameter. Topology supports of major nodes are indicated above branches by bootstrap value. Two DNA barcode-based (ABGD, ASAP) delimitation methods are represented by vertical bars in grey and blue, respectively, on the right side of the tree.

Figure 7. Spectrogram (upper) and oscillograms (lower) of male calling songs of Svistella yayun sp. nov. The red line in spectrogram indicates the peak frequency.

Figure 8. PCA figure description of Svistella species songs. Scatter plot of PC 1 and PC 2 of PCA based on bioacoustics measurements. Except for S. wuyong and S. malu, the remaining species can be clearly identified through the analysis of their calling songs.