Scelimena spicupennis Zheng & Ou, 2003

Qin, Ying-Can, Liu, Jing, Li, Xiao-Dong, Chen, Ya-Zhen & Deng, Wei-An, 2023, On the specific status of Scelimena spicupennis and a new record of S. discalis from China with mitochondrial genome characterization (Orthoptera, Tetrigidae), ZooKeys 1185, pp. 83-104 : 83

Scelimena spicupennis Zheng & Ou, 2003

Figs 4 , 5 , 6

Scelimena spicupennis Zheng & Ou, 2003: 673; Zheng 2005: 55; Deng et al. 2007: 48; Muhammad et al. 2018: 54; Lao et al. 2022: 325.

Links.

http://orthoptera.speciesfile.org/Common/basic/Taxa.aspx?TaxonNameID=1101786.

Material examined.

4♂ 5♀, China, Yunnan prov., Mengla (Bubang), 21.628269 N, 101.612976 E, 710 m alt., 27-29 August 2022, collected by Lei Xin, Xiaodong Li and Linyuan Lu, CLSGNU .

Diagnosis.

This species can be easily distinguished from other species of the genus by the dorsum of pronotum being all dark brown or black, and VL being red. It is morphologically similar to Scelimena bellula Storozhenko & Dawwrueng, 2015 from which it differs in FM forming a cylindrical projection in profile (FM unrecognizable in S. bellula ); dorsum of pronotum is all dark brown or black (external lateral carinae of pronotum are yellow in S. bellula ); dorsal margin of fore femora after the middle with one indistinct tooth and undulate (dorsal margin of fore femora smooth and straight in S. bellula ); dorsal margin of hind femora with one large projection before antegenicular denticle (dorsal margin of hind femora smooth in S. bellula ); sternites of thorax yellow, and sternites of abdomen reddish brown (sternites of thorax and abdomen are reddish brown in S. bellula ). It is also similar to S. guangxiensis Zheng, 1993 but differs from the latter by the pronotum with triangular anterior margin in dorsal view (the pronotum with truncated anterior margin in dorsal view in S. guangxiensis ); VL red (VL not red in S. guangxiensis ); lateral spines of lateral lobes of pronotum directed forwards (lateral spines of lateral lobes of pronotum directed sidewards in S. guangxiensis ); the dorsum of pronotum being all dark brown or black (median carina and discus of pronotum with many yellow dots in S. guangxiensis ).

Redescription.

Female. Body large-sized for the genus. Body surface smooth. Head. Head not exserted above the pronotal surface. Fastigium of vertex short; in dorsal view, the width of the vertex between eyes is nearly equal to the width of compound eye (~ 0.9-1.1 ×); anterior margin of fastigium narrowly arcuate, not surpassing anterior margin of eye; median carina visible anteriorly; lateral margins turned backward; vertex uneven with paired fossulae. In lateral view, the frontal costa invisible before the eyes, protruded anteriorly and broadly rounded between antennal grooves. In the frontal view, the vertex with V-shaped concavity; the frontal costa bifurcated above lateral ocelli, the longitudinal furrow divergent between antennae, width of the longitudinal furrow of the frontal ridge very narrower than the antennal groove diameter. Antennae long, filiform, antennal grooves inserted slightly below inferior margins of compound eyes (upper margin of the antennal groove at level of inferior margin of the compound eye), 15-segmented, 14-segmented: 1st large scapus, 2nd stout pedicel, 3rd - 6th elongated basal segments, 7th and 8th very elongated mid segments (~ 10.0-12.0 × longer than its width), 9th - 11th long subapical segments, 12th - 14th reduced apical segments. Eyes globose, slightly exserted above pronotal surface in lateral view. Lateral (paired) ocelli located slightly below the middle of compound eye height.

Thorax. Pronotum smooth, its dorsum and external lateral carinae without projection (except for FM, FL2 and an obscure tubercle before the shoulder). Pronotum very long (macropronotal state), surpassing much the apex of the hind tibiae. Disc of the pronotum is gently depressed between the prozona and behind the shoulders, the rest is flat. In dorsal view, pronotum with weakly triangular anterior margin; extralateral projections anteriorly armed with strongly projected FL2, which are yellow; FM small and recognizable, FL1 unrecognizable; median carina of the pronotum continuous from the anterior margin to the tip; lateral carinae in the prozona parallel and indistinct; humeral angle obtuse, abbreviated carinae absent; ML absent, external lateral carinae of metazona behind the shoulders smooth and without denticle. In profile, the anterior half of the median carina of pronotum undulated and the posterior half straight; FM small and cylindrical. The ventral margin of the lateral lobe of pronotum curved forwards, VL is strongly produced and sharp. Posterior margins of lateral lobes of pronotum with ventral sinus and tegminal (upper) sinus. Tegmina elongate, punctate, acuminate; visible part of the tegmen 3.0 × as long as wide. Hind wings extend up to the apex of the hind pronotal process.

Legs. Fore and mid femora elongated and not compressed laterally; margins finely serrated, fore femora and mid femora equal in width; dorsal margin of fore femora after the middle with one indistinct tooth and undulate, ventral margin of fore femora straight; dorsal and ventral margins of mid femora slightly undulate, width of middle femora distinctly narrower than the width of the visible part of tegmen. Hind femora elongated, 4.0 × as long as wide, dorsal margin and ventral margin finely serrated, dorsal margin with one inconspicuous projection before antegenicular denticle; antegenicular and genicular denticles small and obtuse. Hind tibia strongly widened at the tip, the margins smooth, and outer side and inner side without a spine. The fore segment of the hind tarsus widened its width 1.2 × the width of the mid femur, dorsolaterally flattened and forming a swimming paddle. Length of the first segment of posterior tarsus longer than third, third pulvillus longer than first and second, apices of first and second acute, apices of third obtuse.

Abdomen. Ovipositor narrow and long, length of upper valvulae 4.7 × its width, upper and lower valvulae with slender saw-like teeth. Length of subgenital plate longer than its width, posterior margin of subgenital plate with three teeth.

Coloration. Body dark brown or black. Antenna black, the area between segments pale. The dorsum of pronotum all dark brown or black; FL2 yellow; VL red. Fore femora and tibiae black; mid femora black, with two yellow spots. Hind femora black, outer dorsal side with two yellow spots. Hind tibia black. The first segment of the posterior tarsus brown. Sternites of thorax yellow, and sternites of abdomen reddish brown; subgenital plate brown.

Male. Similar to females, but smaller and narrower. Subgenital plate is short, cone-shaped, apex bifurcated, subgenital plate reddish brown.

Measurements (mm).

Length of body: ♂ 13.5-14.0, ♀ 19.5-20.0; length of pronotum: ♂ 24.0-25.0, ♀ 30.5-31.6; length of hind femur: ♂ 8.5-9.0, ♀ 9.5-10.5.

Distribution.

P. R. CHINA: Yunnan (Fig. 7 ).

Notes.

Scelimena spicupennis is herewith assigned to the Scelimena bellula species group due to the dorsum of pronotum being very smooth without recognizable projections, similar to S. bellula and S. guangxiensis . Metalateral tubercles are absent. It is easily separated from other species of Scelimena bellula species group by larger FM and a large depression behind the shoulders of the pronotal disk.

Mitochondrial genomes

Analysis of mitochondrial genomes

The sizes of the two sequenced mitogenomes were 17,552 bp ( Scelimena discalis ) and 16,069 bp ( Scelimena spicupennis ). Two mitogenomes had the same gene arrangement and contained 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA unit genes, and a noncoding region (A + T-rich regions). The sequence length, direction and codons of each gene in the mitochondrial genomes of the two Scelimena species are shown in Tables 2 , 3 . The arrangement of 37 genes of the two Scelimena species was the same as in other Tetrigoidea species ( Li et al. 2021); among them, 23 genes (9 protein-coding genes and 14 transfer RNA genes) were located on the majority strand (J-strand), while the remaining genes (four protein-coding genes, eight transfer RNA genes and two ribosomal RNA genes) were encoded on the minority strand (N-strand). The total lengths of the intergenic spacers of the two mitogenomes were 38 bp ( S. discalis ) and 64 bp ( S. spicupennis ). The longest intergenic spacer of S. discalis was located between tRNASer2 and ND1, while that of S. spicupennis was located between rrnL and tRNAVal. The total lengths of the gene overlaps of the two mitogenomes were 68 bp ( S. discalis ) and 54 bp ( S. spicupennis ). The longest overlapping region of S. discalis was between tRNALeu1 and rrnL, and that of S. spicupennis was between tRNATrp and tRNACys.

The total length of 13 protein-coding genes of the two mitogenomes was the same (11,125 bp) in S. discalis and S. spicupennis (Tables 2 , 3 ). For 13 PCGs, the length of each gene ranged from 159 to 1,726 bp, with ATP8 being the shortest (159 bp) and ND5 being the longest (1,726 bp) in both of mitogenomes. All of the PCGs started with the typical ATN (ATT, ATC or ATG) or TTG codon and ended with the complete TAA or TAG codon, with the exception of the ND5 gene, which terminated with an incomplete T. The total lengths of the 22 tRNA genes of the two mitogenomes were 1,433 bp and 1,428 bp. The sizes of the 22 tRNA genes of the two mitogenomes ranged from 61 bp to 69 bp in S. discalis , and from 62 bp to 69 bp in S. spicupennis . The two ribosomal RNA unit genes, rrnL and rrnS, were located between tRNALeu1 and tRNAVal, and between the noncoding region and tRNAVal, respectively. The size of rrnL was 1,315bp ( S. discalis ) and 1,273bp ( S. spicupennis ), and the size of rrnS was 741 bp ( S. discalis )and 738 bp ( S. spicupennis ). The lengths of the noncoding control region were 2,968 bp ( S. discalis ) and 1,495 bp ( S. spicupennis ).

Nucleotide composition analysis

The nucleotide characteristics of the newly obtained mitochondrial genome sequence are shown in Tables 4 , 5 . The nucleotide composition of the two newly sequenced mitogenomes was consistently biased towards A and T nucleotides, which constituted 70.73% ( S. discalis ) and 69.21% ( S. spicupennis ). Comparative analysis showed that the A + T content of the control region was higher than in other regions in S. discalis and S. spicupennis . The two mitogenomes showed a positive AT skew and a negative GC skew, which indicated that the A and C nucleotides were more abundant than the T and G nucleotides. For 13 PCGs, the overall A + T content was also higher than the G + C content. Moreover, the AT skews were negative, -0.112 ( S. discalis ) and -0.111 ( S. spicupennis ), and the GC skews were slightly negative, -0.026 ( S. discalis ) and -0.056 ( S. spicupennis ). The A + T contents of 22 tRNA genes of the two mitogenomes were 72.23% ( S. discalis ) and 71.79% ( S. spicupennis ) and showed positive AT and GC skews. The A + T content was 73.78% to 72.30% in rRNA genes and showed a negative AT skew and a positive GC skew.

Phylogenetic analysis

Using the mitochondrial genomes of the Mirhipipteryx andensis and Ellipes minuta of Tridactyloidea as outgroups, phylogenetic trees were constructed using BI and ML methods based on the sequences of 13 protein-coding genes from the complete mitochondrial genomes of 12 species of Tetrigidae . The result of the phylogenetic trees, as presented in Fig. 8 , indicated that the relationships of the eight genera were as follows: ( Zhengitettix + (( Falconius + ( Paragavialidium + Scelimena )) + ( Criotettix + ( Eucriotettix + ( Loxilobus + Thoradonta ))))). The three Scelimena were clustered into one monophyletic and a holophyletic clade, indicating that they are phylogenetically close and share a common ancestor (Fig. 8 ). Scelimenini ( Scelimena ) and Discotettigini ( Paragavialidium ) were reconstructed as sister groups.

Figures

Figure 4. Scelimena spicupennis, female A body, dorsal view B the same, lateral view C head and anterior part of pronotum, dorsal view D head and anterior part of pronotum, lateral view.

Figure 5. Scelimena spicupennis, female A head, frontal view B right fore femur, lateral view C right mid femur, lateral view D right hind femur, lateral view E right hind tibia, lateral view F right hind tibia, dorsal view G right posterior tarsus, lateral view H right posterior tarsus, dorsal view I subgenital plate of female, ventral view.

Figure 6. Scelimena spicupennis, male A body in dorsal view B body in lateral view.

Figure 7. Distribution map of S. discalis and S. spicupennis.

Figure 8. Phylogenetic trees obtained from A BI and B ML analyses based on 13 protein-coding genes (ND 2, COI, COII, ATP 8, ATP 6, COIII, ND 3, ND 5, ND 4, ND 4 L, ND 6, CytB, ND 1).