Idris longiscapus Debnath, Rajmohana & Sushama, 2025

Sushama, V., Debnath, Rupam, Rajmohana, K. & Dinesh, K. P., 2025, Description of four new species of Idris Förster, 1856 (Hymenoptera: Scelionidae) from India, European Journal of Taxonomy 997, pp. 256-274 : 267-270

Idris longiscapus Debnath, Rajmohana & Sushama sp. nov.

urn:lsid:zoobank.org:act:B28FCAA7-B75F-4428-9ADD-637944507375

Fig. 4

Diagnosis

In the species identification key of Rajmohana (2014), Idris longiscapus Debnath, Rajmohana & Sushama sp. nov. comes close to I. lakshmani ( Mani, 1939) . Since the types of I. lakshmani could not be traced, species comparison was made using the original description. Idris longiscapus can be distinguished from the latter by the colour of the head (black vs honey brown to yellow), smaller HW/ HH (1.4× vs 2.0×), and longer pm (equal to m vs half of m). In the species identification key of Lê (2000), this species runs to I. hunnus Kozlov & Lê, 1987 ; however, I. longiscapus can be distinguished from the latter by the colour of metasoma (pale yellow vs black), sculpture of metapleural epicoxal sulcus (smooth vs foveolate) and shorter T3 (1.6× of T2 length vs 2.2× of T2 length). Among the other Oriental species of Idris , I. longiscapus shows similarity to I. fasciatipennis in having the forewings clouded behind the st. Although the types of I. fasciatipennis are damaged and the species description is insufficient, the elongate scape provides an immediate distinguishing feature, with I. longiscapus having a scape 5.6× as long as wide compared to 3.4× as long as wide in I. fasciatipennis .

Etymology

The specific epithet ‘ longiscapus ’ is derived from the Latin words ‘ longus ’ (long) and ‘ scapus ’ (scape), referring to the elongated scape characteristic of this species. It is intended as an adjective in apposition.

Type material

Holotype

INDIA • ♀; West Bengal: Bankura, Nobanda ; 22.271164° N, 87.141502° E; 110 m alt.; 2 Nov. 2023; Rupam Debnath leg.; ex eggs of Harmochirus brachiatus (Thorell, 1877) ; ZSI/34246/H3.

Paratypes

INDIA • 8 ♀♀; same data as for holotype; ZSI/34247/H3 to ZSI/34254/H3 • 1 ♂; same data as for holotype; ZSI/34255/H3 .

Description

Female

BODY LENGTH. 0.88–0.94 mm (n = 9).

COLOUR. Head, mesosoma, lateral patches on T2 brownish black; metasoma honey brown except T4–T7 brown; mandibles, legs, antennae yellow; wings hyaline except slightly clouded behind the st; setae on body white.

HEAD. 1.2× as wide as high; 1.4× as high as long; 1.8× as wide as long; HW/TSL= 1.4; IOS 0.4× HW; head including vertex setigerous granulate except reticulate antennal scrobe; central keel incomplete, reaching up to mid-level of eye; lagrimal small, smooth; facial striae absent; malar striae absent; eyes densely pubescent; mandible tridentate, middle tooth longer than upper and lower tooth; lateral ocelli contiguous with orbital margin; POL> LOL in ratio of 2:1; POL 6.5× OD; hyper occipital carina absent; occipital carina complete; A1 5.6× as long as wide, 0.8× of clava in length; A2 2.5× of A 3 in length; A3 1.2× as long as wide; proportions of length to width of A1 to A6 (113:20), (54:27), (21:17), (13:19), (12:20), (12:24); clava 2.1× as long as wide.

MESOSOMA. Mesoscutum and mesoscutellum 0.7× and 0.5× as long as wide respectively; mesoscutum finely imbricate, densely setose; mesoscutellum granulose, sparsely setose; notauli absent; mesoscutal suprahumeral sulcus and mesoscutal humeral sulcus absent; scutoscutellar sulcus foveolate laterally in axillar area and smooth medially; posterior mesoscutellar sulcus foveolate; metascutellum smooth; metanotal trough foveolate; propodeum with longitudinal striae, placed apart by 3.0× of its own width, medially with 2 tooth-like projections; pronotal suprahumeral sulcus absent; epomial carina absent; cervical pronotal area granulose; lateral pronotal area smooth; mesopleural pit present; mesopleural carina incomplete, restricted to anterior half; prespecular sulcus foveolate; mesepimeral sulcus foveolate up to mesopleural pit and then present as a strong carina towards mesocoxa; femoral depression smooth; ventral and dorsal metapleural area smooth; metapleural pit distinct, from which metapleural sulcus extends as a smooth furrow anteriorly towards posterior margin of mesopleuron and posteriorly towards posterior margin of metapleuron; metapleural sulcus foveolate anterodorsally; paracoxal sulcus present as a simple furrow.

WINGS. Macropterous; forewing (L:W = 67:24), m: pm: st = 2:2:9; hindwing (L:W = 64:8).

METASOMA. 1.4× as long as wide; T1 with longitudinal parallel costae throughout; T2 with longitudinal parallel costae extending to half of its length, finely reticulate laterally, smooth apically, moderately setose laterally. T3 longest and widest of all tergites, 2.2× as long as T2 with fine reticulation, smooth apically, sparsely setose laterally and sub laterally; T4 imbricate basally, smooth apically, sparsely setose; T5 smooth; T6 and T7 not visible in dorsal view; proportions of width to length of T1 to T5 (107:50), (147:81), (248:180), (213:36), (123:6); S1 longitudinally costate; S2 with a row of fovea basally followed by longitudinal parallel costae reaching up to ⅔ of its length, reticulate laterally, smooth apically; S3–S6 reticulate, moderate to densely setose.

Male

Body length = 0.84 mm. Morphologically similar to females with the main exception of antenna. Antenna 12-merous, length to width ratio of A1–A12 (13:3), (6:3), (4:3), (4:3), (4:3), (4:3), (4:3), (4:3), (4:3), (4:4), (3:3), (6:4).

Biology

Reared from the eggs of Harmochirus brachiatus ( Salticidae : Araneae ) ( Rajmohana et al. 2025).

Distribution

West Bengal ( India), Pakistan (based on BLAST search).

Variation

Some of the females have T2 smooth basally and then entirely longitudinally costate. In addition, differences in female body length are noted (see description above).

Molecular characterization

The mt COI sequence of I. longiscapus (GenBank: PP574570) shows a minimum of 12.2% genetic distance to an unidentified species of Idris from Canada (GenBank: MG514562 ). Interestingly, the BLAST search of I. longiscapus sequence retrieved 99.8% similarity to a sequence of unpublished scelionid specimen from Pakistan (GenBank: KY842170 ).

Phylogenetic analysis

The maximum likelihood tree ( Fig. 5 ) for the species of Idris has moderate bootstrap support for most of the larger sub-clades within Idris . Bootstrap support was comparatively good among the sister species and terminal nodes when compared to interspecies relationships and deeper nodes. In addition to the four new species, another lineage represented by male specimens was barcoded (GenBank accession nos. OR960562 and OR960563). This lineage appears to be distinct, comprising an undescribed species ( Fig. 5 ). However, since morphological taxonomy in Scelionidae is predominantly based on females, this lineage could not be formally described. In another instance of gregarious development, the parasitoids failed to emerge from a spider egg sac. However, they were barcoded (GenBank accession numbers PP356719 and PP356718), and genetic analysis confirmed their conspecificity with I. hyllus sp. nov.

Figures

Fig. 4. Idris longiscapus Debnath, Rajmohana & Sushama sp. nov., holotype, ♀ (ZSI/34246/H3). A. Lateral habitus. B. Dorsal habitus. C. Frontal view of head.D. Antenna.E. Lateral view of mesosoma. F. Dorsal view of mesosoma and propodeum.G. Dorsal view of metasoma.H. Ventral view of metasoma. Scale bars: A–B = 0.2 mm; C–H = 0.02 mm.

Fig. 5. Maximum likelihood tree for species of Idris Förster, 1856 based on 647 bp mt COI sequences. Bootstrap values are indicated on the nodes.