Ixodiphagus aethes Hayat

Hayat, Mohammad & Veenakumari, Kamalanathan, 2015, Description of four new species of brachypterous Encyrtidae (Hymenoptera: Chalcidoidea) from India, Zootaxa 3990 (2), pp. 259-271 : 263-265

2. Ixodiphagus aethes Hayat , sp. nov.

( Figs 11–16 )

Female. Holotype. Length, 0.9 mm Head dark brown. Antenna with scape brownish yellow, upper surface and lower margin brown; pedicel brownish yellow, upper surface brown; funicle yellow; clava brown. Mesosoma dark brown; metanotum and propodeum brown; tegula dark brown. Fore wing rudiment dark brown ( Fig. 16 ). Legs with coxae black; trochanters whitish; femora and tibiae dark brown; all tarsi with segments 1–4 yellow to brownish yellow, last segment brown. Gaster black. Head, dorsum of pro- and mesothorax, and gaster densely hairy ( Figs 11–14 )

Head ( Figs 11 , 13 ) dorsum very slightly convex; occipital margin sharp and concave; head 2.07× as broad as median length; frontovertex broad, 0.74× head width, or head width 1.35× as broad as frontovertex width; anterior margin of frons medially concave; eye posteriorly separated from occipital margin by about diameter of two facets; ocelli very small, difficult to see in the densely punctate frontovertex, but apparently ocellar triangle with apical angle strongly obtuse; posterior ocellus nearer to eye margin than to occipital margin (ca. OOL, 1.5; OCL, 2); head, in frontal view, 1.68× as broad as high; antennal torulus with lower margin in line with lower margin of eye; torulus placed higher on head, separated from mouth margin by a distance 1.42× inter-torular distance (10:7); scrobes inverted V-shaped, with margins sharp; head, in profile, subtriangular, with eye longer than high (10:7); malar space greater than eye height (10:7); frontovertex finely reticulate, with deep, circular, setigerous punctures, separated by about their own diameters; facial region and malar space reticulate; head densely setose, setae long, largely off-white, but some pale brown, with 4 long setae along occipital margin each about twice length of other setae; eye setose, setae brown, each seta as long as a facet diameter. Antenna ( Figs 12 , 14, 15 ) [left antenna lost] with scape flattened and expanded beneath, with upper margin rounded, 1.5× as long as broad; pedicel slightly longer than F1–F3 combined; funicle segments all transverse; F1 slightly broader than F2; F2–F6 gradually increasing in width; F2 onwards with eccentric articulation, and each ventrally longer than dorsally; clava with first segment distinctly separated from second segment; third segment obliquely truncate, truncate part as long as dorsal lengths of second and third segments combined; clava as long as F2–F6 combined. Relative measurements (holotype, on card)—head dorsal width, 27; head dorsal length, 13; frontovertex width, 20; head frontal height, 16; eye height (head in profile), 7; malar space, 10; antennal scape length (width), 9 (6); pedicel length, 5; funicle length, 8; clava length, 7.

Mesosoma ( Figs 11 , 13 ) 0.71× gaster length; pronotum rectangular, 2.33× as broad as long and 1.8× as long as mesoscutum; mesoscutum 4.6× as broad as long, and slightly more than half length of scutellum; scutellum 1.6× as broad as long; propodeum very narrow in middle half; pronotum, mesoscutum and scutellum with raised reticulate sculpture and deep, circular setigerous punctures, each separated from other punctures by slightly more than its own diameter; setigerous punctures on scutellum arranged in 10 longitudinal lines; setae on pronotum and mesoscutum off-white, with a line of 4 long, pale brown setae along posterior margin of mesoscutum; scutellum with setae pale brown, arranged in 10 longitudinal lines. Fore wing rudiment a subtriangular plate ( Fig. 16 ), reaching posteriorly to basal third of TI of gaster. Legs short and robust; coxae with several long white setae; tibiae with prominent bristle-like setae, each arising from a small tubercle. Relative measurements (holotype, on card)— mesosoma length, 25; pronotum length (width), 9 (21); mesoscutum length (width), 5 (23); scutellum length (width), 10 (16).

Metasoma ( Figs 11, 12 ). Gaster with TI distinctly longer than following four tergites individually; tergites reticulate, with minute, setigerous punctures; setae about as follows: TI with 3 transverse lines; TII–TVI each with a single line of setae; TVII with several setae; hypopygium extending to 0.71× gaster length ( Fig. 12 ).

Male. Unknown.

Material examined. Holotype, ♀ (on card, with left fore wing on slide, No. EH.1778; left antenna lost), labelled “ INDIA: TAMIL NADU: Dindigul, Shembaganur, 2.iv.2014 (MT), Coll. K. Veenakumari” ( NBAIR, registration No. ICAR / NBAIR /EN.41)

Distribution. India: Tamil Nadu.

Etymology. Greek, aethes = unusual, curious; refers to the unusual habitus and the large, rectangular pronotum.

Comments. This new brachypterous species is not at all similar to either the brachypterous species ( I. taiaroaensis ) from New Zealand, or to the other macropterous species. It differs from all the species by the following combination of characters: pronotum rectangular, 1.8× as long as mesoscutum; mesoscutum transverse, 4.6× as broad as long; frontovertex with deep, circular, setigerous punctures, each separated by about its own diameter from others; pronotum, mesoscutum and scutellum with similar setigerous punctures, separated by slightly more than their own diameters, and those on scutellum arranged in 10 longitudinal lines; fore wing short, subtriangular, with apex reaching to basal third of TI of gaster; antenna with scape flattened, 1.5× as long as broad; funicle segments transverse, F2 onwards with eccentric articulation; first segment of clava distinctly separated from second segment; head, pronotum, mesonotum and gaster densely setose; tibiae of all legs with long, bristlelike setae, each arising from a small tubercle.

Figures

FIGURES 11, 12. Ixodiphagus aethes Hayat, sp. nov. Female: holotype: 11, body, dorsal; 12, body, lateral.

FIGURES 13 – 16. Ixodiphagus aethes Hayat, sp. nov. Female: holotype: 13, head and mesosoma, dorsal; 14, head and part of mesosoma, latero-ventral view; 15, antenna; 16, fore wing.