Chelonus pseudobasalis
author(Tobias et Lozan, 2006)
synonyms
body
shapeBody black. length: 1.9mm [TL4]. 1.9 - 2.0mm [T14]
color
head
shapeIn dorsal view rounded behind eyes, 1.7 times as broad as long, a little broader than mesosoma. In frontal view 1.1 times as broad as high. Ocelli small, not widely separated, POL = 1.3 times OOL [OOL = 1.3 * POL? (fig. 1)]. Temples as long as transverse diameter of the eye [TL4][T14].
sculptureHead behind eye, face and frons very faintly striate. Clypeus very faintly punctate and shining[TL4].
colorLabiomaxillary complex brown [TL4].
antenna
shape ♀Antennae with 16 segments, shorter than head and mesonotum combined; scape 2.5-3 times as long as wide; 3rd segment about 3 times as long as wide, apical segments 1.5 times as long as wide, 6-14th segments a little widened [TL4]. Antennae equal to the total length of the head and mesosoma; 3rd antennal segment 3 times as long as wide, apical segments 1.5 times as long as wide [T14].
shape ♂
color
mesosoma
shapeIn dorsal view almost as broad as carapace. In lateral view 1.5 times as long as high and almost as long as length of carapace. Propodeum with very faint transversal carina, (centrally almost missing), lateral tubercles small [TL4].
sculptureMesonotum anteriorly granulate punctate, area before scutellum with some undulations. Scutellum faintly punctate, centrally smoother and shining. Propodeum granulate [TL4].
color
legs
shapeFore and hind femora 3-3.5 times as long as broad. Hind tibiae 1.2 times longer than femora and as long as tarsi. Outer spur of hind tibiae longer than inner spur, almost reaching two-thirds of 1st metatarsal segment [TL4]. Inner spur of the hind tibia distinctly shorter than half of the hind metatarsus [T14].
sculpture
colorAll coxae dark; all femora brown; fore tibiae yellowish, hind tibiae yellowish with brown belt at apices; all tarsi brown [TL4]. Fore tibia brownish yellow, hind tibia yellowish, their apical third and base brown. The tarsi are brown [T14]
wings
shapeMarginal cell in forewing not large, 1-R1 0.7 times of length of pterostigma. Second submarginal cell comparatively large, 1.3 times smaller than radial cell. 3-SR 1.2 times as long as r, 3-SR 4 times shorter than SR1 [TL4].
colorForewings slightly infuscate. Portions of costal vein brown, rest of vein, including pterostigma (except upwards) and metacarpus brownish and almost transparent [TL4].
metasoma
shapeCarapace oval, almost not incurved apicoventrally, 1.8 times as long as maximum width [TL4][T14].
sculptureCarapace granulate with faint longitudinal and winding undulations spanning at maximum half its visible surface [TL4].
colorCarapace basally with a dark brown hue, slightly contrasted with the rest of back colouring [TL4]. The metasoma is brown in the basal part [T14].
♀ ovipositorOvipositor hidden [TL4].
♂ aperture♂ unknown
other info
distributionCzech Republic [TL4]. CZ [FE].
remarksThe species is defined by small body length (less than 2mm) and smooth sculpturing. Flagellar segments 4-12 arc slightly widened and antenna is shortened.
Undoubtedly it greatly resembles M. basalis (Curtis), but differs in the absence of a yellow basal spot (although there is a trace of dark-brown colouring basally and laterally like the yellow spot in basalis), in shape of head (basalis has a bigger head, roundly widened behind eye). Both species are more smoothly sculptured, with similar vein architecture and slightly wider antennal segments 4-12 [TL4].
hosts
type description
Microchelonus pseudobasalis sp. n.
Female
Head. In dorsal view rounded behind eyes, 1.7 times as broad as long (34 : 20), a little broader than mesosoma. In frontal view 1.1 times as broad as high. Ocelli small, not widely separated, POL = 1.3 times OOL. Temples as long as LO. Antennae with 16 segments, shorter than head and mesonotum combined; scape 2.5-3 times as long as wide; 1st flagellar segment about 3 times as long as wide, apical segments 1.5 times as long as wide, 4-12th segments a little widened.
Mesosoma. In dorsal view almost as broad as carapace. In lateral view 1.5 times as long as high and almost as long as length of carapace.
Wings. Radial cell in forewing not large, its length along the metacarp 0.7 times of length of pterostigma. Second radio-medial cell comparatively large, 1.3 times smaller than radial cell. Second radial abscissa 1.2 times as long as first abscissa, 4 times shorter than third abscissa.
Legs. Fore and hind femora 3-3.5 times as long as broad. Hind tibiae 1.2 times longer than femora and as long as tarsi. Outer spur of hind tibiae longer than inner spur, almost reaching two-thirds of 1st metatarsal segment.
Metasoma. Carapace oval, almost not incurved apicoventrally, 1.8 times as long as maximum breadth. Ovipositor hidden.
Sculpture. Head behind eye, face and frons very faintly striate. Clypeus very faintly punctate and shining. Mesonotum granulate punctate. Scutum anteriorly granulate punctate, area before scutellum with some undulations. Scutellum faintly punctate, centrally smoother and shining. Propodeum granulate with very faint transversal carina, (centrally almost missing), lateral tubercles small. Carapace granulate with faint longitudinal and winding undulations spanning at maximum half its visible surface.
Colour. Body black. Labiomaxillary complex brown. Carapace basally with a dark brown hue, slightly contrasted with the rest of back colouring. Legs: all coxae dark; all femora brown; fore tibiae yellowish, hind tibiae yellowish with brown belt at apices; all tarsi brown. Forewings slightly infuscate. Portions of costal vein brown, rest of vein, including pterostigma (except upwards) and metacarpus brownish and almost transparent.
Body length: 1.9mm.
Male. Unknown.
Diagnostics. The species is defined by small body length (less than 2mm) and smooth sculpturing. Flagellar segments 4-12 arc slightly widened and antenna is shortened.
Taxonomic affinity and comparison. Undoubtedly it greatly resembles M. basalis (Curtis), but differs in the absence of a yellow basal spot (although there is a trace of dark-brown colouring basally and laterally like the yellow spot in basalis), in shape of head {basalis has a bigger head, roundly widened behind eye). Both species are more smoothly sculptured, with similar vein architecture and slightly wider antennal segments 4-12.
Data used in the multi-access key
These data are collected from the species descriptions and redescriptions, from published figures and photographs and from own measureements and observations. For a description of the different variables and value classes see this
pdf.
| morphology |
| basic information | female | male |
| body length (mm): | (1.7) 1.7 - 2.1 (2.2) | (1.7) 1.7 - 2.1 (2.2) |
| number of antennal segments: | 16 | --- |
| head, dorsal view |
| Head width : length | narrow | narrow |
| Temples narrowing - widening | parallel | parallel |
| Eye length : temple length | 0.75 - 1.0, 1.0 - 1.25 | 0.75 - 1.0, 1.0 - 1.25 |
| Roundness temple | strong, medium | strong, medium |
| POL : OD | 3 - 4 | 3 - 4 |
| Ocellar triangle shape | narrow | narrow |
| Excavation of head | 15 - 25% | 15 - 25% |
| head, lateral view |
| Head height : length | very long | very long |
| Eye height : length | long | long |
| Temple length : eye length | very short | very short |
| head, frontal view |
| Head width : height | very narrow, narrow | very narrow, narrow |
| Face width : height | very narrow, narrow | very narrow, narrow |
| Eyes converging ventrally | distinctly converging, about parallel | distinctly converging, about parallel |
| EH : MSL | long | long |
| Clypeus width : height | quadrangular, semicircular | quadrangular, semicircular |
| Clypeus extending above bottom of eyes | below | below |
| Tentorial pits | large, very large | large, very large |
| Shape of lower margin clypeus | convex, truncate | convex, truncate |
| antennae |
| Antennal shape | --- | filiform, not widened |
| Segment 3 length : width | --- | --- |
| Penultimate segment length : width | --- | --- |
| Length of antenna : length of body | 2: short | --- |
| mesosoma, lateral view |
| Length : height | medium, long | medium, long |
| transverse carina | --- | --- |
| lateral teeth | --- | --- |
| mesosoma, ventral view |
| Prepectal carina lamelliform | indistinct | indistinct |
| legs |
| Hind femur length : width ratio | --- | --- |
| Hind tibia length : hind tarsus length ratio | --- | --- |
| Hind tibia (longest) spur length : metatars length ratio | | |
| wings |
| Vein 1-R1 length : pterostigma length | medium, long | medium, long |
| Vein r length : vein 3-SR length | short | short |
| Shape vein SR1 (straight / concave / convex) | slightly convex, convex | slightly convex, convex |
| S-shape vein SR1 | apically concave, not S-shaped | apically concave, not S-shaped |
| cell M : cell Sm2 | Sm2 large, Sm2 medium | Sm2 large, Sm2 medium |
| Pterostigma length : width ratio | short | short |
| Angle between radial vein (r) : vein 1-R1 | sharp | sharp |
| metasoma, dorsal view |
| Length : width ratio of metasoma | short, medium | short, medium |
| Shape of metasoma | widest in middle, widest towards apex | widest in middle, widest towards apex |
| metasoma, lateral view |
| Length : height ratio of metasoma | medium | medium |
| posterior : anterior height ratio of metasoma | small, medium | small, medium |
| Position of maximum height | medium, medium-posterior | medium-posterior |
| metasoma, ventral view |
| Metasoma posteriorly curved forwards | --- | --- |
| male apical aperture |
| Aperture width : metasoma width | no aperture | small, medium, large |
| Aperture shape | n. a. | (nearly) round, oval, elongate - slit |
| Median process shape | n. a. | --- |
| sculpture |
| head |
| general coarseness | fine | fine |
| clypeus |
| coarseness punctation | punctulate | punctulate |
| density punctation | --- | --- |
| face |
| sculpture type | striate | striate |
| sculpture direction | --- | --- |
| vertex and temple |
| sculpture type | striate (striolate) | striate (striolate) |
| mesonotum |
| sculpture type | notauli distinct | notauli distinct |
| scutellum |
| middle | smooth | smooth |
| lateral | punctate | punctate |
| metasoma |
| base - mid sculpture | longitudinally rugose / rugose-striate | longitudinally rugose / rugose-striate |
| sculpture at apex | rugulose | rugulose |
| coarse / fine boundary | base (to 50%) | base (to 50%) |
| color |
| head |
| mandibles color pattern | --- | --- |
| palpi, lightest color | brown, red | brown, red |
| antennae |
| scapus, lightest color | black, dark brown | black, dark brown |
| segment 3 and 4, lightest color | black, dark brown | black, dark brown |
| legs |
| fore coxae lightest colour | dark | dark |
| fore femur lightest colour | medium dark | medium dark |
| fore femur color pattern | entirely light | entirely light |
| hind femur lightest colour | medium dark | medium dark |
| hind femur color pattern | entirely dark | entirely dark |
| hind tibia lightest colour | medium light | medium light |
| hind tibia color pattern | narrow light ring | narrow light ring |
| hind basitarsus lightest colour | medium dark | medium dark |
| hind tarsus segment 2-3 lightest colour | medium dark | medium dark |
| wings |
| middle veins lightest colour | medium light | medium light |
| basal veins lightest colour | medium light, light | medium light, light |
| metasoma |
| metasoma colour pattern | entirely dark, color only on basal third | entirely dark, color only on basal third |
| metasoma lightest colour | dark, medium dark | dark, medium dark |
| metasoma base, colour pattern | entirely dark, entirely colored | entirely dark, entirely colored |
| metasoma base, light spots | n.a. | n.a. |
| metasoma base, light band | n.a. | n.a. |
Chelonus pseudobasalis in published keys
T14: Tobias, 2010
Palearctic species of Microchelonus Szépligeti (Hymenoptera: Braconidae, Cheloninae): key to species.
