Paraxenos hungaricus ( Székessy, 1955 ), Palearctic

Benda, Daniel, Pohl, Hans, Nakase, Yuta, Beutel, Rolf & Straka, Jakub, 2023, A new species of the genus Paraxenos Saunders, 1872 (Strepsiptera: Xenidae) from Bembix digger wasps (Hymenoptera: Bembicidae) and a redescription of Paraxenos hungaricus (Székessy, 1955), European Journal of Taxonomy 885 (1), pp. 134-155 : 142-149

Paraxenos hungaricus ( Székessy, 1955)

Figs 3 , 4A–E , 5–6

Pseudoxenos (Bembicixenos) hungaricus Székessy, 1955: 281 (type locality: Hungary, Bugac).

Paraxenos (Bembicixenos) hungaricus – Kinzelbach 1971: 162.

Diagnosis

Female cephalothorax

Differing from P. arabicus sp. nov. and P. krombeini in several characters. Maxilla cone-shaped, narrowing anteriorly like in P. krombeini , but blunt apically (mx, Fig. 6E ). Anteriorly directed, very slightly overlapping with mandible proximally. Maxillary base approximately 2–3× as wide as anterior part of maxilla (mxb, mx, Fig. 6E–F ). Mandible enclosed in mandibular capsule like in P. arabicus , versus overtopping anterior edge of the head capsule in P. krombeini . Mandibular base flat, not divided by furrow from genal area. Labial area between maxillae distinctly wider than long in midline (lba, Fig. 6C ), versus slightly wider than long in P. arabicus (lba, Fig. 2A ). Dorsal labral field slightly arcuate (dlf, Fig. 6D ), versus distinctly arcuate in P. arabicus and P. krombeini . Mouth opening usually conspicuously sclerotized, but only indistinctly in P. arabicus . Lateral extensions of head capsule predominantly dull on ventral side, cuticle wrinkled, but shiny area near submaxillary groove without conspicuous dark papillae (lehc, Fig. 3C ; lehc, smxg, Fig. 6A ), versus lateral extensions completely dull and covered by dark papillae in P. arabicus . Dark lateral region of abdominal segment I below spiracles distinctly contrasting to pale thorax from dorsal side (asI, Fig. 3D ). Clypeal lobe slightly protruding from head capsule (cll, Fig. 3C ), but distinctly protruding in P. krombeini and P. arabicus .

Male cephalotheca

See the Diagnosis section under P. arabicus sp. nov.

Material examined

CZECH REPUBLIC • 1 MP; Bzenec env.; 12 Jun. 2015; M. Halada leg.; host: Bembix rostrata (Linnaeus, 1758) ; NMPC .

HUNGARY • allotype ♀; Bugac env.; 30 Jul. 1941; Móczár leg.; host: Bembix oculata Panzer, 1801 ; HNHM • 2 ♀♀; Agasegyháza env.; 15 Jul. 1956; Bajári leg.; host: Bembix oculata Panzer, 1801 ; HNHM • 1 MP, 1 ♀; Agasegyháza env.; 16 Jul. 1956; Mihályi leg.; host: Bembix oculata Panzer, 1801 ; HNHM • 1 MP, 1 ♀; Fülophaza env.; 17 Jul. 2013; J. Straka leg.; host: Bembix oculata Panzer, 1801 ; NMPC • 1 ♀; Fülophaza env.; 12 Aug. 2011; P. Bogusch and J. Straka leg.; host: Bembix oculata Panzer, 1801 ; NMPC .

IRAN • 1 ♀; Kerman, 20 km E of Ghobira ; 5 Jun. 2010; Mi. Halada leg.; host: Bembix sp. ; OLML .

ITALY • 1 MP; Sicilia, Mts S of Etna; 21 Jun. 2012; J. Halada leg.; host: Bembix rostrata (Linnaeus, 1758) ; OLML • 3× 1 MP, 1 ♀; Sardinia, 30 km NW of Sassari ; 19 May 2013; J. Halada leg.; host: Bembix rostrata (Linnaeus, 1758) ; NMPC .

KAZAKHSTAN • 1 MP; Lepsi env.; 20 Jun. 1995; M. Múčka leg.; host: Bembix sp. ; NMPC • 1 ♀; same collection data as for preceding; hosts: Bembix rostrata (Linnaeus, 1758) ; OLML • 1 MP; 50 km S of Balkhash ; 28 Jun. 1992; K. Deneš leg.; host: Bembix oculata Panzer, 1801 ; OLML • 1 empty male puparium (EMP), 2 EMP; Matai desert; 25 Jun. 1995; J. Halada and M. Múčka leg.; host: Bembix rostrata (Linnaeus, 1758) ; OLML .

MONGOLIA • 3× 1 MP; Gobi , 70 km SE of Khatansuudal; 11 Jul. 2005; P. Tyrner leg.; host: Bembix sp. ; NMPC .

TURKEY • 1 MP; 40 km NE of Muradiye ; 5 Jul. 2000; M. Halada leg.; host: Bembix rostrata (Linnaeus, 1758) ; OLML • 24× 1 ♀, 2× 2 ♀♀, 1 ♀, 1 EMP, 2 ♀♀, 1 MP, 6× 1 MP; 20 km W of Van ; 5 Jul. 1997; M. Halada leg.; host: Bembix rostrata (Linnaeus, 1758) ; OLML .

Description

Female cephalothorax

SHAPE AND COLORATION. Compact, widened, slightly or distinctly wider than long. Size variable, length 1.28–1.93 mm, maximum width 1.68–2.57 mm. Anterior head margin slightly or scarcely protruding from head capsule. Thorax widening posteriorly. Cephalothorax displaying multiple light brown shades, only around mandible and mouth opening cuticle more sclerotized and darker, but lighter in central region, darker laterally.

HEAD CAPSULE. Approximately ⅓ to ½ as long as entire cephalothorax including lateral extensions. Coloration pale to dark, with specific pattern. Clypeal area distinctly or indistinctly separated from labral area, slightly protruding anteriorly or not protruding. Clypeal lobe blunt. Surface slightly wrinkled on dorsal side, reticulated. Lateral extensions of head capsule predominantly dull on ventral side, cuticle wrinkled, but shiny area near submaxillary groove lacking conspicuous dark papillae (lehc, Fig. 3C , lehc, smxg, Fig. 6A ). Clypeal sensilla present on ventral side of clypeus, mainly concentrated on clypeal lobe (cls, Fig. 6D ). Border between clypeal and frontal region indistinct, but still recognizable ( Fig. 5F ). Frontal region of head capsule distinctly wrinkled, not covered by dark papillae. Segmental border between head and prothorax indistinct on dorsal side, indicated by change in cuticular surface structure.

SUPRA-ANTENNAL SENSILLARY FIELD. Predominantly smooth or slightly wrinkled, with dispersed sensilla (sssf, Fig. 5C–D ), delimited by distinct furrow medially (fssf, Fig. 6B ).

ANTENNA. Preserved as cavity, rarely combined with rounded plates (a, Fig. 5C–D ). Antennal sensilla or vestigial setae missing. Periantennal area smooth, reduced when supra-antennal sensillary field almost reaches vestige of antennae (paa, ssf, Fig. 5C–D ).

LABRUM. Ventral field distinctly wider than long, elliptic or semicircular. Dorsal field slightly arcuate to nearly straight,> 4× as wide as long in midline. Dorsal field with about 24 setae inserted in deep sockets ( Fig. 6C–D ).

MANDIBLE. Anteromedially directed at an angle of 30–35°, enclosed in mandibular capsule. Mandibular bulge not distinctly raised, with ca 12–18 sensilla (mdbs, Fig. 6E–F ). Cuticle completely smooth anteriorly, but posteroventrally sculptured, reticulated. Mandibular tooth slightly widened, pointed apically, anteriorly directed, armed with distinct spines (mdt, mdts, Fig. 6E–F ). Mandibular base flat, not divided by furrow from genal area.

MAXILLA. Well-developed, prominent and separated from labial area. Cuticle smooth. Maxilla cone-shaped, wide at base, but narrowing distally, maxillary base approximately 2–3× as wide as distal part (mxb, mx, Fig. 6E–F ). Anteriorly directed, very slightly overlapping with mandible proximally. Vestige of palp present, with more or less distinct plates, located anteriorly on ventral side of maxilla. Additional sensilla present on ventral maxillary surface (mxs, Fig. 6E–F ). Submaxillary groove distinctly produced posterolaterally (smxg, Fig. 6A ).

LABIUM. Labial area between maxillae distinct, delimited anteriorly by mouth opening and posteriorly by birth opening. Distinctly wider than long in midline, rectangular, flat. Cuticular surface very slightly wrinkled, reticulated.

MOUTH OPENING. Mouth opening straight or bi-arcuate, sclerotized along margin.

THORAX. Pro-mesothoracic and meso-metathoracic borders distinct on ventral side, separated by mesal furrows (sbpm, sbmm, Fig. 3C ). Border on dorsal side indistinct, indicated by different cuticular sculpture. Border between metathorax and abdomen formed by ridge in combination with changed cuticular sculpture and coloration. Cuticle of thoracic segments reticulate on ventral side, with small, scattered pigmented papillae. Prosternal extension variable, differentiated by cuticular sculpture and coloration (pst, Fig. 3C ). Anterior part usually darker, with more or less distinct pigmented papillae medially. Posterior part usually pale and without conspicuous pigmented papillae. Meso- and metathorax unmodified in shape, transverse. Posteromedial pale area on mesosternum and metasternum variable in shape, in some specimens indistinct (mst, mtst, Fig. 3C ). Dorsal side of thorax smooth or slightly reticulated.

ABDOMINAL SEGMENT I AND SPIRACLES. Lateral region of abdominal segment I below spiracles conspicuously darkened on dorsal side, contrasting to pale thorax (asI, Fig. 3D ). Spiracles on posterior half of cephalothorax slightly elevated, with lateral or laterodorsal orientation.

Male cephalotheca

SHAPE AND COLORATION. In frontal view rounded, slightly flattened, elliptic, length 0.63–0.78 mm, width 1.23–1.53 mm, in lateral view protruding anteriorly, pointed apically. Coloration forming pattern of pale and dark shades ( Fig. 4A–B ).

CEPHALOTHECAL CAPSULE. Compound eyes visible, pale to dark, with dark individual cornea lenses. Gena completely pale except dark area around mandibular base; pale area between compound eye and mandibular base narrowed (nearly as wide as diameter of compound eye) (gn, coe, Fig. 4A ). Clypeus pale medially (on clypeal lobe) and darker laterally. Clypeus (clypeal lobe) straight in frontal view, prominent in lateral view, but blunt apically (cl, Fig. 4B ). Clypeal lobe distinctly wider than mandibular length (cll, Fig. 4E ). Clypeal sensilla mainly concentrated on clypeal lobe, visible or indistinct ( Fig. 4A, E ). Frontal region with paired furrow of supra-antennal sensillary field, lacking impression or occipital bulge (fssf, Fig. 4A–E ). Diameter of genae between maxillary base and compound eye approximately 2× as large as diameter of vestigial antenna.

SUPRA-ANTENNAL SENSILLARY FIELD. Dark (ssf, Fig. 4A, E ), kidney-shaped and bulging, delimited medially by distinct furrow. Furrows wide, not connected anteriorly. Dark sensilla visible ( Fig. 4E ).

ANTENNA. Of standard shape, dark, small, with small plates or sensilla and complete torulus (a, Fig. 4A, E ). Periantennal area dark, not clearly delimited from supra-antennal sensillary field.

LABRUM. Labral area distinct. Dorsal field pale or dark, with dispersed setae visible. Ventral field conspicuously darkened (dlf, Fig. 4E ).

MANDIBLE. Nearly medially directed. Tooth inconspicuous, apically pointed, wide basally, but not reaching area of mandibular bulge. Coloration pale with darker parts. Mandibular bulge with sensilla, separated from pointed tooth. Distance between mandibles very distinctly exceeding mandibular length ( Fig. 4E ).

MAXILLA. Distinct, prominent, with darker and paler parts. Vestige of palp present, conspicuous (mxp, Fig. 4A, E ). Wide at base, approximately 2× as wide as mandible (mx, Fig. 4A, E ).

LABIUM AND HYPOPHARYNX. Labium distinct between and below maxillae, darker. Praementum and postmentum almost completely fused, indistinctly separated by furrow. Hypopharyngeal protuberance present or absent (hyp, Fig. 4E ).

MOUTH OPENING. Visible, not covered by ventral labral field, slightly arcuate, sclerotized around margin.

Hosts

Bembix oculata Panzer, 1801 ; Bembix rostrata (Linnaeus, 1758) ; Bembix sp. ( Kinzelbach 1978; Benda et al. 2022b).

Distribution

Palearctic: Czech Republic; Germany; Hungary; Italy; Mongolia; Spain ( Székessy 1955; Kinzelbach 1978; Benda et al. 2021); Turkey ( Benda et al. 2022b); Iran; Kazakhstan (this tudy).

Figures

Fig. 3. Paraxenos hungaricus(Székessy, 1955), host, female cephalothorax (OLML). A. Bembix rostrata (Linnaeus, 1758) stylopized by P. hungaricus, lateral view. B. Detail of host abdomen of B. rostrata, with adult female. C. P. hungaricus from B. rostrata, ventral side of cephalothorax. D. P. hungaricus from B. rostrata, 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); sb ma = segmental border between metathorax and abdomen; sb = segmental border between mesothorax and metathorax; sb = mm pm segmental border between prothorax and mesothorax; sp = spiracle.

Fig. 4. A–E. Paraxenos hungaricus (Székessy, 1955), ♂ (NMPC). F. Paraxenos arabicus Benda & Straka sp. nov., ♂ (NMPC). A. Frontal view of cephalotheca). B. Lateral view of cephalotheca. C. Ventral view of anterior part of the puparium. D. Dorsal view of anterior part of the puparium. E. Detail of cephalotheca, frontal view. F. Detail of cephalotheca, frontal view. Abbreviations: a = vestigial antenna; asI = abdominal segment I; cl = clypeus; cll = clypeal lobe; coe = compound eye; csI = constriction of abdominal segment I; dlf = dorsal labral field of labral area; fr = frontal region (frons); fssf = furrow of supra-antennal sensillary field; gn = gena; hyp = hypopharynx; lgI = foreleg; lgII = middle leg; lgIII = hindleg; md = mandible; mst = mesosternum; mtst = metasternum; mx = maxilla; mxp = vestige of maxillary palp; pom = postmentum; prm = praementum; pst = prosternum; sb hp = segmental border between head and prothorax; sb = segmental border between metathorax and ma abdomen; sb = segmental border between mesothorax and metathorax; sbpm = segmental border mm between prothorax and mesothorax; ssf = supra-antennal sensillary field; vlf = ventral labral field of labral area; wbI = wing buds I; wbII = wing buds II.

Fig. 5.Paraxenos hungaricus (Székessy, 1955), ♀ (OLML), SEM micrographs. 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: a = vestigial antenna; asI = abdominal segment I; cl = clypeus; fr = frontal region; frons; frp = frontal papillae; lehc = lateral extension of head capsule; mst = mesosternum; mtst = metasternum; paa = periantennal area; pst = prosternum; sb cf = segmental border between clypeus and frons; sp = spiracle; ssf = supra-antennal sensillary field; sssf = sensillum of supra-antennal sensillary field.

Fig. 6. Paraxenos hungaricus (Székessy, 1955), ♀ (OLML), cephalothorax, SEM micrographs. 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: cl = clypeus; cls = clypeal sensillum; dlf = dorsal labral field of labral area; lba = labial area; ls = labral seta in cavity (spine-shaped sensillum); md = mandible; mx = vestige of maxilla; mxb = maxillary base; mxs = maxillary sensillum; sb cl = segmental border between clypeus and labrum; smxg = submaxillary groove; vlf = ventral labral field of labral area.

Fig. 2. Paraxenos arabicus Benda & Straka sp. nov. A–B. Female (NMPC), cephalothorax. C–D. Male (NMPC), cephalotheca. A. Detail of ventral side. B. Detail of dorsal side. C. Frontal view. D. Lateral view. Abbreviations: a = vestigial antenna; cl = clypeus; cll = clypeal lobe; coe = compound eye; dlf = dorsal labral field of labral area; fr = frontal region; fssf = furrow of supra-antennal sensillary field; gn = gena; lba = labial area; lehc = lateral extension of head capsule (lateral cephalic extension); md = mandible; mx = vestige of maxilla; mxb = maxillary base; mxp = vestige of maxillary palp; os = mouth opening; pom = postmentum; prm = praementum; pst = prosternum (prosternal extension); pstp = prosternal papilla; sbhp = segmental border between head and prothorax; smxg = submaxillary groove; ssf = supra-antennal sensillary field; vlf = ventral labral field of labral area.