Contribution to the Knowledge of Dicranoptychini (Diptera, Tipuloidea, Limoniidae) in China, with the First Mitochondrial Genome of the Tribe and Its Phylogenetic Implications

Abstract

Dicranoptychini is a tribe in the subfamily Limoniinae (Diptera, Tipuloidea, and Limoniidae) and includes only the genus Dicranoptycha Osten Sacken, 1860. However, the species diversity of the tribe in China was seriously underestimated, and the taxonomic status of Dicranoptycha has long been controversial. In this study, types of Chinese Dicranoptycha species and specimens collected from several localities in China were examined, and the first mitochondrial (mt) genome of the tribe Dicranoptychini is presented. Two Dicranoptycha species, D. jiufengshana sp. nov. and D. shandongensis sp. nov., from China, are described and illustrated as new to science. A Palaearctic species, D. prolongata Alexander, 1938, is recorded in China for the first time. In addition, the complete mt genome of D. shandongensis sp. nov. is sequenced and annotated, indicating that it is a typical circular DNA molecule with a length of 16,157 bp and shows a similar gene order, nucleotide composition, and codon usage to mt genomes of other Tipuloidea species. The two pairs of repeat elements are found in its control region. Phylogenetic results confirm the sister-group relationship between Cylindrotomidae and Tipulidae, question the position of the genus Epiphragma Osten Sacken, 1860 in Limoniidae, and indicate that Dicranoptychini may be a basal lineage within Limoniinae.

Keywords: Chinese fauna; Dicranoptycha; Dicranoptychinae; identification key; mitogenome; new record; new species; phylogeny; taxonomy.

Figure 1

Dicranoptycha jiufengshana sp. Nov. (a) Habitus of male, lateral view; (b) head, lateral view; (c) thorax, dorsal view; (d) wing. Scale bars: 2.0 mm (a); 0.5 mm (b,c); 1.5 mm (d).

Figure 2

Dicranoptycha jiufengshana sp. Nov. (a) Male hypopygium, dorsal view; (b) male hypopygium, ventral view. Scale bar: 0.2 mm.

Figure 3

Dicranoptycha jiufengshana sp. Nov. (a) Complex of aedeagus, dorsal view; (b) complex of aedeagus, lateral view; (c) complex of aedeagus, ventral view; (d) female ovipositor, dorsal view; (e) female ovipositor, lateral view; (f) female ovipositor, ventral view; (g) vaginal apodeme. Scale bars: 0.2 mm (a–c,g); 0.5 mm (d–f).

Figure 4

Dicranoptycha prolongata Alexander, 1938. (a) Habitus of male, lateral view; (b) head, lateral view; (c) thorax, dorsal view; (d) wing. Scale bars: 2.0 mm (a); 0.5 mm (b,c); 1.5 mm (d).

Figure 5

Dicranoptycha prolongata Alexander, 1938. (a) Male hypopygium, dorsal view; (b) male hypopygium, ventral view. Scale bar: 0.2 mm.

Figure 6

Dicranoptycha prolongata Alexander, 1938. (a) Complex of aedeagus, dorsal view; (b) complex of aedeagus, lateral view; (c) complex of aedeagus, ventral view; (d) female ovipositor, dorsal view; (e) female ovipositor, lateral view; (f) female ovipositor, ventral view; (g) vaginal apodeme. Scale bars: 0.2 mm (a–c,g); 0.5 mm (d–f).

Figure 7

Dicranoptycha shandongensis sp. nov. (a) Habitus of male, lateral view; (b) head, lateral view; (c) thorax, dorsal view; (d) wing. Scale bars: 2.0 mm (a); 0.5 mm (b,c); 1.5 mm (d).

Figure 8

Dicranoptycha shandongensis sp. nov. (a) Male hypopygium, dorsal view; (b) male hypopygium, ventral view. Scale bar: 0.2 mm.

Figure 9

Dicranoptycha shandongensis sp. nov. (a) Complex of aedeagus, dorsal view; (b) complex of aedeagus, lateral view; (c) complex of aedeagus, ventral view; (d) female ovipositor, dorsal view; (e) female ovipositor, lateral view; (f) female ovipositor, ventral view; (g) vaginal apodeme. Scale bars: 0.2 mm (a–c,g); 0.5 mm (d–f).

Figure 10

Dicranoptycha shandongensis sp. nov. (a) Habitat of Zhongshan Temple, Mengyin, Shandong, China; (b) habitat of Beijiushui, Mount Laoshan, Laoshan, Shandong, China.

Figure 11

Gene map (a) and control region (b) of the mitochondrial genome of Dicranoptycha shandongensis sp. nov.

Figure 12

Relative synonymous codon usage (RSCU) of the protein-coding genes in the mitochondrial genome of Dicranoptycha shandongensis sp. nov. Leu1 = Leu (UUR); Leu2 = Leu (CUN); Ser1 = Ser (AGN); Ser2 = Ser (UCN).

Figure 13

Phylogenetic trees of Tipuloidea inferred from the datasets (a) PCGRNA, (b) PCG12RNA, (c) PCG, and (d) PCG12 under the Bayesian inference (BI) method. The number at each node is the posterior probability (PP).

Figure 14

Phylogenetic trees of Tipuloidea inferred from the datasets (a) PCGRNA, (b) PCG12RNA, (c) PCG, and (d) PCG12 under the maximum likelihood (ML) method. The number at each node is the bootstrap value (BV).