Orthopelma chinensis Zhang, 2025

Zhang, Chuan-Xi, 2025, A new species of the genus Orthopelma (Hymenoptera: Ichneumonidae: Orthopelmatinae) from China, Zootaxa 5666 (1), pp. 145-150 : 146-149

Description o f Orthopelma chinensis Zhang , sp. nov.

( Figs 1–9 )

Diagnosis: This new species of Orthopelma , can be recognized by the following combination of characters: clypeus fused with face and not separated by a transverse carina; antennal length in females shorter than combined head + thorax length, with13 flagellomeres; malar space 0.8× as long as width of mandibular base; confluent propodeal basal area and areola; ovipositor sheath 0.7× hind tibia length.

Specimens examined: Holotype: female, east campus of Ningbo University , Ningbo, China, N29°90′93″, E121°63′59″, 10 m, reared in 15 IV 2024 from galls collected in 18 VII 2023, Chuan-Xi Zhang. Holotype deposited in the Chou Io Insect Museum, Ningbo, China.

Body: (♀). Total body length 5.0 mm; fore wing length 2.9 mm ( Fig. 1 ), hind wing length 2.2mm.

Head: face distinctly narrowed ventrally; interocular distance on frons 1.5× that on lower face. Face with dense setae. Distance from eye margin to lateral ocellus 2.2× ocellar diameter. Malar space 0.8× mandibular basal width. Labrum semicircular, protruding beyond clypeus apex; clypeus fused with face and not separated by a transverse carina ( Fig. 2 ). Clypeus subrectangular with acute lateral angles and with a distinct, regularly arcuate notch in the center of its lower margin. Filiform flagellum with 13 flagellomeres ( Fig. 3 ), total length 1.42 mm. Basal flagellomeres 1–7 combined length 1.5× eye maximum diameter; basal flagellomeres 1–3 combined length 0.68× eye maximum diameter. Subapical flagellomeres (≈4) subquadrate in lateral view.

Mesosoma: mesoscutum densely setiferous-punctate ( Fig. 4 ). Mesopleuron smooth and shining, bearing a distinct curved striate groove from prepectal carina to lower posterior corner ( Fig. 5 ). Metapleuron setiferous-punctate. Propodeum with prominent carinae; basal and areolar areas confluent, combined length 1.7× width (Figs. 4,7). Petiolar area width 1.6×length, with coarse transverse rugae; costula connecting to basal area posteriorly. Hind femur length 0.7 mm, 2.7× femoral width. All tarsal claws with large basal lobe ( Fig. 6 ). Fore wing lacking areolet; nervulus positioned slightly distad of basal vein. Hind wing nervellus non-inclivous.

Metasoma: 1 st tergite 3.7× longer than wide, lateral margins parallel posteriorly; ventrolateral/dorsolateral carinae complete. Spiracle small, circular, sublateral at ≈1/3 basal length ( Figs. 7–8 ). 2 nd tergite length equal to width; 3 rd tergite 0.65× longer than wide. Ovipositor sheath 0.68 mm, 0.7× hind tibia length, about equal to 2 nd tergite length ( Figs.1, 9 ).

Colour ( Fig 1 ): primarily black. Clypeus black basally, dark brown apically; labrum yellowish. Maxillary and labial palps uniformly yellowish ( Fig. 2 ). Scape and pedicel dark brown; tegulae yellowish ( Fig.4 ). 1 st tergite entirely black; 2 nd tergite yellowish-brown basally (1/2), black-brown medially (3/10), yellowish-brown apically; 3 rd tergite yellowish-brown basally (2/5), black-brown medially (2/5), yellowish-brown apically; 4 th –7 th tergites black. 3 rd –6 th sternites yellowish-brown with black-brown lateral spots. Fore coxa yellowish-brown; mid coxa black with brownish apex; hind coxae mostly black. Trochanters brown; trochantelli yellow. Fore/mid femora brown; hind femora black-brown.: Fore/mid tibiae brown; hind tibiae black-brown. Tarsi yellow; claws and basal lobes black-brown. Wings hyaline with dense microtrichia; pterostigma brown.

Biology ( Figs 10–17 ): the Orthopelma specimen was reared from galls collected from Rosa multiflora , and galls were similar in morphology to those induced by Diplolepis japonica on R. multiflora ( Fig. 10 ). Larvae overwinter within galls, pupate in situ and emerge in April of the following year ( Figs.11–14 ). However, the host gall maker remains reclusive since our rearing yields no specimens of putative gall maker, only the cynipid gall wasps ( Periclistus sp ) ( Figs.15–17 ), which were reported as inquiline gall wasps of Cynipidae , emerged from the galls.

Male: unknown.

Phylogenic relationships

The COI sequences of Orthopelma deposited in public databases remain scarce, with only three species represented: two widely distributed species ( O. brevicorne and O. mediator ) including geographically distinct populations, and an unidentified Orthopelma species. A 658 bp COI sequence of O. chinensis (GenBank accession no. PV528831) was compared via BLAST analysis, revealing 92.77–93.32% identity to O. brevicorne populations and 88.37– 89.59% identity to O. mediator populations. The interspecific COI sequence divergence between O. brevicorne and O. mediator ranged from 90.81% to 92.17%. Additionally, O. chinensis COI showed 87.98% identity to the unidentified Orthopelma species.

Phylogenetic trees inferred from available Orthopelma COI sequences robustly supported the placement of the new species within Orthopelma and its close affinity to O. brevicorne ( Figs 18–19 ). A 970 bp fragment of the 5.8 S ribosomal RNA gene and internal transcribed spacer 2 (ITS2) was also amplified and sequenced for O. chinensis (GenBank accession no. PV528304). This sequence demonstrated 96.1–96.9% identity to O. mediator ITS 2 sequences, the only Orthopelma species with publicly available ITS data in Databases.

Figures

FIGURES 1–9. Orthopelma chinensis sp. nov. 1 Female in lateral view. 2 Head in anterior view 3 Antenna. 4 Head and mesosoma in dorsal view. 5 Mesosoma in lateral view. 6 Claws. 7 Propodeum and 1st tergite in dorsal view. 8 first metasomal segment in lateral view, the red arrow indicates spiracle. 9 Ovipositor.

FIGURES 10–17. Galls, pupae and associated cynipid gall wasps. 10 Galls on Rosa multiflora, from which Orthopelma chinensis specimens was reared. 11 newly pupated O. chinensis pupa. 12 O. chinensis pupa 6 days. 13 O. chinensis pupa 10 days (1 day before emergence). 14 newly emerged adult. 15 gall with cynipid wasp larvae. 16 male inquiline wasp Periclistus sp. 17 female inquiline wasp Periclistus sp.

FIGURES 18–19. Phylogeny inferred using the Maximum Likelihood (18) and Maximum Parsimony method (19) in MEGA12. The percentage of replicate trees in which the associated taxa clustered together (1,000 replicates) is shown next to the branches (cut-off value 50% for condensed tree). Four species from Ichneumonoidae, Dolichomitus terebrans and Syrphoctonus nigritarsus, and two Mesochorus sp. were used as the outgroup. All the COI sequences used in this analysis can be downloaded from GenBank (Accession Number for each sample shown in the trees).