Eupathocera zethi Benda & Straka, 2024

Benda, Daniel, Pohl, Hans, Beutel, Rolf & Straka, Jakub, 2024, Solitary folded-winged wasps of the genus Zethus Fabricius (Vespidae, Zethinae) parasitised by two new species of Strepsiptera on different continents, Journal of Hymenoptera Research 97, pp. 721-739 : 721-739

Eupathocera zethi Benda & Straka sp. nov.

Type material.

Holotype • French Guiana: 1 ♀; Cayenne, Roura env., 18 Oct. 2015; Naoki Ogawa leg.; NMPC; host: Zethus brasiliensis fuscatus R. Bohart & Stange, 1965 .

Paratypes • French Guiana: 1 ♀; same host specimen (collection data) as for holotype, 18 Oct. 2015; Naoki Ogawa leg.; YNPC ; 1 ♀ + 1 empty male puparium (EMP), 2 ♀; 35 km S of Roura, Relais de Patawa , 16 July 2000; Ji. Kadlec leg.; OLML; same host species as holotype ; 1 ♀; NE Mount de Kaw Fourgassie , 5. Aug. 2006; M. Snížek; OLML; same host species as holotype .

Diagnosis of female cephalothorax.

This species is diagnosed by a combination of characters. It differs from all remaining species of Eupathocera by the presence of very conspicuously imprinted mesal furrows indicating the pro-mesothoracic and meso-metathoracic borders on the ventral side (sbpm, sbmm; Figs 1 C , 2 A ), and inconspicuous mandibles fused with the labial area and bearing a rounded (not distinctly raised) mandibular bulge (mdb; Fig. 3 E ). The clypeal surface is completely smooth with distinctly exposed sensilla, in contrast to Eupathocera luctuosae Pierce, 1911 and E. insularis (Kifune, 1983) , which display a wrinkled, lamellar clypeal area, with scarcely visible sensilla. The number of clypeal sensilla is very high in the new species, more than 60. A larger number occurs only in species utilising Sphex L., 1758 – Eupathocera fuliginosi (Brethes, 1923) (more than 60) and E. westwoodi (Templeton, 1841) (more than 80). The border between the clypeal area and frontal region is indistinct in comparison to Eupathocera luctuosae Pierce, 1911 and E. insularis (Kifune, 1983) where it is clearly recognisable.

Description of female cephalothorax.

Shape and colouration. Size of holotype cephalothorax: length 1.8 mm, width 1.74 mm; slightly variable, as long as wide or slightly wider than long, length 1.78–2.03 mm, width 1.74–1.83 mm. Abdominal segment I not protruding laterally, corner below spiracles rounded. Anterior head margin rounded, not protruding from head capsule. Thorax slightly widening posteriorly. Colouration of cephalothorax mostly dark with light brown pattern on ventral side, but mostly light brown dorsomedially with specific contrast pattern.

Head capsule. Approximately ⅓ as long as entire cephalothorax including lateral extensions. Colouration mostly dark with specific pattern with paler lateral extensions, mandibular bases and ventral labral field. Clypeal area distinctly delimited from labral area. Clypeal lobe rather indistinct but visible. Clypeal surface completely smooth with distinctly exposed sensilla. Number of clypeal sensilla slightly over 60. Border between clypeal and frontal region indistinct but still present. Frontal region smooth or very slightly wrinkled (fr, Fig. 2 F ). Segmental border between head and prothorax indicated by dark transverse stripe on dorsal side (sbhp, Fig. 1 D ), in SEM pictures visible by change in cuticular sculpture (sbhp, Fig. 3 B ). Head and prothorax distinctly separated by birth opening ventromedially (bo, Fig. 3 A ) and laterally by suture (sbhp, Fig. 3 A ).

Supra - antennal sensillary field. Smooth or very slightly wrinkled, with dispersed sensilla (Fig. 2 C, D ). Not distinctly delimited by furrow medially, but border marked by different surface structure of supra-antennal sensillary field and smooth frontal region (Fig. 3 B ).

Antenna. Vestigial antenna bulging, preserved as more or less clearly defined area, with distinct plates (pra, Fig. 2 C, D ). Antennal torulus reduced (Fig. 2 C, D ). Periantennal area expanded, smooth (paa, Fig. 2 C, D ). Distance between antennal area and supra-antennal sensillary field relatively large.

Labrum. Ventral field wider than long, elliptic, completely smooth, shiny, and pale, contrasting with dark dorsal labral field and labium. Dorsal labral field slightly arcuate, 5 × wider than long in midline. Setae on dorsal field blunt, sensilla-like, spines lacking.

Mandible. Anteromedially directed at an angle of 30 °, enclosed in mandibular capsule. Mandibular bulge not distinctly raised, rounded, with several inconspicuous sensilla. Cuticle of mandible smooth posteriorly, with longitudinal grooves dorsolaterally (md; Fig. 3 E, F ). Mandibular tooth narrow, anteriorly oriented, with or without spines (mdt; Fig. 3 E, F ).

Maxilla. Distinctly reduced and only very slightly protruding, not projecting beyond mandible anteriorly. Partially fused to labial area, both regions not clearly separated. Cuticle reticulated, with smooth areas, not distinctly wrinkled (mx; Fig. 3 E, F ). Vestige of palp inconspicuous, forming small bulge with impression, located medially on ventral side of maxilla. Submaxillary groove indistinctly produced posterolaterally towards maxillary base.

Labium. Labial area not distinctly recognisable between maxillae, flat, slightly longer than wide in midline (lb; Fig. 3 C ). Anteriorly delimited by mouth opening, posteriorly by birth opening. Cuticular surface very slightly reticulated.

Mouth opening. Slightly arcuate, sclerotised along margin (os; Fig. 3 C ).

Thorax. Pro-mesothoracic and meso-metathoracic borders distinct on ventral side, separated by mesal furrows (sbpm, sbmm; Figs 1 C , 2 A ). On dorsal side separated by less conspicuous dark mesal furrows (sbpm, sbmm; Figs 1 D , 2 B ). Border between metathorax and abdomen marked by change in cuticular surface structure or pigmentation. Cuticle of thoracic segments reticulate on ventral side, often with scattered small papillae. Dorsal side of thorax predominantly smooth, only slightly wrinkled. Prosternal extension undifferentiated. Prosternum bulging, distinctly elevated above head medially and laterally (pst; Fig. 3 A ). Shape of meso- and metathorax unmodified, transverse. Prosternum and mesosternum on ventral side with dark colouration, but metasternum medially pale. All thoracic segments pale on dorsal side, but dark laterally.

Abdominal segment I and spiracles. Setae and cuticular spines present on lateral region of abdominal segment I (Fig. 2 E ). Spiracles on posterior ~ ⅓ of cephalothorax slightly elevated, with anterolateral or anterodorsal orientation. Cephalothoracic part of abdominal segment I below spiracles dark on dorsal side, medially paler on ventral side (asI; Figs 1 C , 2 A ).

Etymology.

The name refers to the host genus Zethus . From Greek Zethus – the son of Zeus in ancient Greek mythology. Adjective.

Figures

Figure 1. Eupathocera zethi Benda & Straka, sp. nov., host, female cephalothorax A Zethus brasiliensis fuscatus R. Bohart & Stange, 1965 stylopised by E. zethi sp. nov., lateral view B detail of host abdomen of Z. brasiliensis fuscatus, with two female cephalothoraces C – D holotype of E. zethi sp. nov., ♀ (NMPC) from Z. brasiliensis fuscatus C ventral side of cephalothorax D dorsal side of cephalothorax. Abbreviations: asI – abdominal segment I, cll – clypeal lobe, csI – constriction of abdominal segment I, lehc – lateral extension of head capsule, mst – mesosternum, mtst – metasternum, pst – prosternum (prosternal extension), sbhp – segmental border between head and prothorax, sbma – segmental border between metathorax and abdomen, sbmm – segmental border between mesothorax and metathorax, sbpm – segmental border between prothorax and mesothorax, sp – spiracle.

Figure 2. Holotype of Eupathocera zethi Benda & Straka, sp. nov., ♀ (NMPC), SEM micrographs of cephalothorax A ventral side B dorsal side C right vestigial antenna, dorsal side D left vestigial antenna, dorsal side E left lateral border of abdominal segment I below spiracle, dorsal side F detail of anterior border of cephalothorax, dorsal side. Abbreviations: asI – abdominal segment I, fr – frontal region, lehc – lateral extension of head capsule, mst – mesosternum, mtst – metasternum, paa – periantennal area, pra – plate of vestigial antenna, pst – prosternum (prosternal extension), sbmm – segmental border between mesothorax and metathorax, sbpm – segmental border between prothorax and mesothorax, ssf – supra-antennal sensillary field.

Figure 3. Holotype of Eupathocera zethi Benda & Straka, sp. nov., ♀ (NMPC), SEM micrographs of cephalothorax A anterior part of cephalothorax, ventral side B anterior part of cephalothorax, dorsal side C mouthparts, ventral side D detail of anterior border of cephalothorax, ventral side E right mandible and maxilla, ventral side F left mandible and maxilla, ventral side. Abbreviations: bo – birth opening, lb – labial area, md – mandible, mdt – mandibular tooth, mx – vestige of maxilla (maxilla), pst – prosternum (prosternal extension), os – mouth opening, sbhp – segmental border between head and prothorax.