Chelonus exilis

Chelonus exilis

authorMarshall, 1885

synonymsexcavatus Tobias [T14].

body

shape♂ ♀ Length, 1 1/3 lin. (3.0mm) [M]. Body 3-4mm [T4][Ab2]. ♀ 3.0 - 3.5mm, ♂ 3.0mm [T14]. 3.2mm [By1]. 3.0mm [Te1].

colorBlack. Body dull, minutely scabrous, and sparingly beset with grey pubescence [M]. Body black, finely and densely sculptured [T14].

head

shapeHead subcubical, not contracted behind the eyes, temples dilated; frontal fovea minute, obsolete [M]. Head 1/2 as long as wide, not wider than mesonotum. Head behind eyes broadened, wider here than in ocular region [T4]. Head from above with almost straight and long parallel temples. Head 1.1 times as wide as mesoscutum, 1.45 times as wide as long. Temples twice as long as the transverse diameter of the eye. The width of the ocellar triangle is greater than OOL by the diameter of the ocellus. POL is twice the diameter of an ocellus. Longitudinal diameter of eye 1.8 times transverse, 3 times height of malar space. Face width 1.5 times its height. Palpi equal to the height of the face. ♂ Temples angularly projecting backward (side view) [T14]. Head transverse, narrowed towards the back, relative proportions of length: width: height as 25:44:40, transverse diameter of the eyes shorter than the width of the temples; Malar space almost twice as long as the base of the mandible. Eyes longer than wide (20: 9); OOL longer than POL (9: 7); Maxillary palps shorter than head height (17:40). Rostrum distinct [By1]. The head is slightly transverse, strongly widened posteriorly. The face is twice as wide as high; malar space three times shorter than the longitudinal diameter of the eye; temples 1.5 times the width of the eye. The ocelli are small; the distance between the ocelli and the eyes is three times the diameter of the ocellus [Te1].

sculptureHead subcoriaceous, clypeus almost smooth [M]. Vertex behind ocelli in posterior part with transverse rugae [T14]. Face densely punctated and shiny; Clypeus edged and finely punctated [By1]. Head rugose-striated. Clypeus smooth, shiny [Te1].

colorpalpi blackish ; mandibles tip reddish [M].

antenna

shape ♀Antennae ♀ 16 segments [M]. ♀ Antennae thin and long, apical segments 2-3 times as long as wide [T4]. Antennae equal to the total length of the head and mesosoma; length of segments in apical third of flagellum equal to or slightly greater than their width. Length of 3rd segment 3 times its width, preapical one slightly longer than its width, two previous ones equal to their width, apical one twice its width [T14]. Antennae shorter than body (11:60), scapus thick and oval, twice as long as wide; third segment 3.3 times and penultimate segment 2.2 times as long as it is wide [By1].

shape ♂Antennae ♂ 23 segments [M][S1]. Antennae 20-21-segmented [T14]. Antennae 23-25-segmented [Te1].

color

mesosoma

shapeScutellum not margined; post-scutellum not elevated. Propodeum with 2 or 3 longitudinal raised lines, bluntly bidenticulate [M]. Pronotal collar extending slightly forward (beyond vertical plane, touching the anterior margin of mesonotum) [T4]. Mesosoma length 1.5 times its height. Propodeum with weak transverse carina and lateral teeth [T14]. Relative proportions of length: width: height as 31:20:20 [By1]. Propodeum with transverse carina and lateral teeth [Te1].

sculptureMesonotum punctulate, subcoriaceous. Propodeum reticulated [M]. Mesonotum in front of scutellum with finely meshed sculpture [T14]. Mesonotum smooth, rest of mesosoma densely punctated and matt, scutellum more finely punctated [By1]. Mesonotum slightly rugose, matte, notauli weak. Scutellum rugose, sides of mesosoma coarsely rugose [Te1].

color

legs

shape♀ Hind femur 3 times, ♂ 4 times as long as wide [P14]. Relative length ratios of the rear coxa : trochanter: femur : tibia: tarsus as 11: 5: 16: 23: 23; Hind femora 2.5 times as long as wide. The spurs of the hind tibia are shorter than the 2nd tarsal segment (5: 7) and as long as the fourth [By1]. Legs slightly thickened [Te1].

sculpture

colorFore legs yellow-brown, their femora black at the base. Hind- and middle legs black, tibiae reddish-brown, the hind pair dark at the base and apex; tarsi dark. [M]. Hind femora black [T4]. Apical half of fore femora and fore tibia brownish yellow [T14]. Legs are black; tibiae of all legs more or less reddish [Te1].

wings

shapeMarginal cell larger than the stigma; SR1 straight; radius of the hind wings sinuated. wings, 2 1/3 lin. [M]. 1-R1 as long as stigma [T4]. 1-R1 is slightly shorter than the pterostigma. The marginal cell of the fore wing is twice as large as the 2nd submarginal cell [T14]. Fore wing (Fig. 7) shorter than the body (61:80), SR1 ends far in front of the wing tip; r almost as long as the width of the pterostigma and as long as 3-SR; 3-SR half as long as 2-SR and shorter than r-m (5:7); SR1 3 times as long as 3-SR [By1]. 1-R1 shorter than pterostigma. r equal to r-m and shorter than 3-SR. SR1 straght, three times longer than 3-SR. 2-SR 2.5 times 3-SR. 1-CU1 = 1/3 2-CU1. The radial vein of the hind wing is almost straight [Te1].

colorWings blackish-transparent, veins and stigma brownish-grey, parastigma and costa darker; tegulae dark [M]. Wings smoky, wing veins and pterostigma blackish brown [By1]. The wings are light; the pterostigma is brown [Te1].

metasoma

shapeMetasoma as long as the head and mesosoma, of the ♂ slightly widened and obtuse behind, of the ♀ elliptical [M]. ♂ Metasoma 2.5 times as long as wide, ♀ Metasoma quite distinctly narrowed posteriorly, its posterior margin not curved forward [T4]. ♀ Metasoma with small obtuse tooth at apex, 2.2 times as long as wide, carapace bent apically anteriorly by 0.15 times its length. ♂ metasoma 2–2.1 times as long as wide [T14]. Metasoma (Fig. 8) almost parallel-sided, longer than the mesosoma (37:30) [By1]. The metasoma is elliptical [Te1].

sculptureBasal half of metasoma finely reticulate, posterior punctulate; basal carinae none [M]. Metasoma with smooth longitudinal rugae [T4]. Rugose, streaks clearly at the base [By1]. Metasoma with weak longitudinal rugae at the base [Te1].

colormetasoma immaculate [M].

♀ ovipositorOvipositor visible, but not reaching the apex; valves yellow-brown, compressed, hairy [M]. Ovipositor valves equal to 0.5 times the length of the folded part of the carapace [P14]. The ovipositor is short [Te1].

♂ apertureAnal aperture of the ♂ nearly circular [M]. Aperture without carina-like protuberance (only small mammilate protuberance hidden in its depth) [T4]. Aperture is small, rounded, almost punctate [T14]. Aperture rounded or slightly transverse [Te1].

other info

distributionBE,CH,DE,FR-F,GB-G,NL,PL [FE]

remarksThis species differs from C. parcicornis, Schaff., in the number of joints of the antennae; from sulcatus, Nees, in its more slender form, dilated cheeks, and longer antennae; from latrunculus, n. s., similarly, and also in the colour of the legs [M].

hostsCosmopteryx Lienigiella, Zell. [M][Sh1]. Cosmopleryx scribaiella Zeil. [Sh1].

figures

fig. 1: habitus (Tobias 1986)	fig. 2: head, dorsal view (Tobias 1986)	fig. 3: ~~metasoma, dorsal view~~ (Tobias 1986)
fig. 4: ♀ head, dorsal view (Tobias 2010)	fig. 5: ♀ metasoma, dorsal view (Tobias 2010)	fig. 6: ♀ metasoma, lateral view (Tobias 2010)
fig. 7: fore wing (Beyarslan 1995)	fig. 8: metasoma (Beyarslan 1995)

references

code	reference	type of info
Ab2	Abdínbekova 1971	k
By1	Beyarslan 1995	df
M	Marshall 1885	Tk
S1	Szepligeti 1908	k
S4	Szepligeti 1898	k
Sh1	Shenefelt 1973	hosts
Te1	Telenga 1941	dk
T13	Tobias 2000	k2
T14	Tobias 2010	dk
T17	Tobias 1989	k
T4	Tobias 1986	kf
FE	van Achterberg 2021	Fauna Europaea
legend:	Type description \| Redescription \| description \| in key \| comment \| nom. nov. \| figure(s) \| photo(s)

links

Fauna Europaea

photos

fig. 1: ♂ lateral view (Arp)	fig. 2: ♂ dorsal view (Arp)
fig. 3: ♂ latero-dorsal view (Arp)	fig. 4: ♂ posterior view (Arp)
fig. 5: ♂ frontal view (Arp)	fig. 6: ♀ dorsal view (Arp)
fig. 7: ♀ lateral view (Arp)	fig. 8: ♀ latero-dorsal view (Arp)

type description

Marshall 1885

17. Chelonus exilis, n. s.

Niger, abdomine immaculato, palpis nigricantibus, mandibulis apice rufis. Pedes antici testacei, femorum basi nigra; posteriores nigri tibiis obscure ferrugincis, posticis apice basique fuscis ; tarsi fusci. Alae fumato-hyalinae. stigmate nervisque pallide, parastigmate et costa obscurius fuscis; squamulae nigricantes; areola radialis stigmate major; abscissa Stia recta; alarum inferiorum radius sinuatus. Corpus param nitidum, subtiliter scabriculum, parcius cano pubescens. Caput subcubicum, pone oculos haud contractum, genis dilatatis, subcoriaceum, clypeo laeviore; fovea frontalis minima, obsoleta. Antennae maris 23-, feminae 16-articulatae. Mesomesosoma subtiliter punctulatus, subcoriaceus. Scutellum immarginatum; post-scutellum haud elevatum. Metamesosoma reticulatus, in longitudinem bis terve carinulatus, obtuse bideuticulatus. Maris rima analis fere orbicularis; feminae terebra conspicienda quidem, sed anum haud attingens, recta, valvulis compressis, testaceis, pilosis.

Black; metasoma immaculate; palpi blackish ; mandibles tipped with rufous; fore legs testaceous, their femora black at the base; posterior legs black, their tibiae obscurely rufous, the hind pair fuscous at the base and apex; tarsi fuscous. Wings fumato-hyaline, nervures and stigma pale fuscous, parastigma and costa darker; squamulie fuscous; radial areolet larger than the stigma; 3d abscissa straight; radius of the hind wings sinuated. Body dull, minutely scabrous, and sparingly beset with grey pubescence. Head subcoriaceous, subcubical, not contracted behind the eyes, cheeks dilated; clypeus almost smooth; frontal fovea minute, obsolete. Antennae ♂ 23-, ♀ 16-jointed. Mesosoma punctulate, subcoriaceous. Scutellum not margined; post-scutellum not elevated. Metasoma reticulated, with 2 or 3 longitudinal raised lines, bluntly bidenticulate. metasoma as long as the head and mesosoma, of the ♂ slightly widened and obtuse behind, of the ♀ elliptical; finely reticulated at the base, afterwards punctulate; basal carinae none. Anal aperture of the ♂ nearly circular; terebra of the ♀ visible, but not reaching the anus; valves testaceous, compressed, hairy. ♂ ♀ . Length, 1 1/3; wings, 2 1/3 lin.

This species differs from C. parcicornis, Schaff., in the number of joints of the antennae; from sulcatus, Nees, in its more slender form, dilated cheeks, and longer antennae; from latrunculus, n. s., similarly, and also in the colour of the legs.

Described from two males and a female, which were bred, June 5th, by Warren from Cosmopteryx Lienigiella, Zell.

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):	(2.8) 2.8 - 4 (4.2)	(2.8) 2.8 - 4 (4.2)
number of antennal segments:	16	(20) 20 - 24 (25)
head, dorsal view
Head width : length	very narrrow, narrow	very narrrow, narrow
Temples narrowing - widening	widening, strongly widening	widening, strongly widening
Eye length : temple length	<= 0.75	<= 0.75
Roundness temple	very strong, strong, medium, weak	very strong, strong, medium, weak
POL : OD	<= 2, 2 - 3	<= 2, 2 - 3
Ocellar triangle shape	very narrow, narrow	very narrow, narrow
Excavation of head	15 - 25%, 25 - 35%	15 - 25%, 25 - 35%
head, lateral view
Head height : length	very long	very long
Eye height : length	very short, short	very short, short
Temple length : eye length	short, long	short, long
head, frontal view
Head width : height	very narrow, narrow	very narrow, narrow
Face width : height	very narrow	very narrow
Eyes converging ventrally	---	---
EH : MSL	very long	very long
Clypeus width : height	---	---
Clypeus extending above bottom of eyes	---	---
Tentorial pits	---	---
Shape of lower margin clypeus	---	---
antennae
Antennal shape	---	filiform, not widened
Segment 3 length : width	medium	---
Penultimate segment length : width	short	---
Length of antenna : length of body	2: short	---
mesosoma, lateral view
Length : height	medium	medium
transverse carina	weak, indistinct	weak, indistinct
lateral teeth	weak, small, short, present	weak, small, short, present
mesosoma, ventral view
Prepectal carina lamelliform	indistinct	indistinct
legs
Hind femur length : width ratio	short	short
Hind tibia length : hind tarsus length ratio	medium	medium
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 concave, straight or S-shaped	slightly concave, straight or S-shaped
S-shape vein SR1	not S-shaped	not S-shaped
cell M : cell Sm2	Sm2 medium	Sm2 medium
Pterostigma length : width ratio	medium, long	medium, long
Angle between radial vein (r) : vein 1-R1	sharp, medium	sharp, medium
metasoma, dorsal view
Length : width ratio of metasoma	medium, long	medium, long
Shape of metasoma	narrowing to apex, widest in middle	narrowing to apex, widest in middle
metasoma, lateral view
Length : height ratio of metasoma	long	long
posterior : anterior height ratio of metasoma	small	small
Position of maximum height	medium, medium-posterior	medium-posterior, posterior
metasoma, ventral view
Metasoma posteriorly curved forwards	(almost) not incurved, just/slightly incurved, (distinctly) incurved	(almost) not incurved, just/slightly incurved, (distinctly) incurved
male apical aperture
Aperture width : metasoma width	no aperture	small, medium
Aperture shape	n. a.	(nearly) round
Median process shape	n. a.	---
sculpture
head
general coarseness	---	---
clypeus
coarseness punctation	smooth to uneven	smooth to uneven
density punctation	---	---
face
sculpture type	punctate	punctate
sculpture direction	---	---
vertex and temple
sculpture type	transverse rugulose	transverse rugulose
mesonotum
sculpture type	notauli distinct, notauli slightly distinct	notauli distinct, notauli slightly distinct
scutellum
middle	rugulose	rugulose
lateral	rugulose	rugulose
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	light tip	light tip
palpi, lightest color	black, dark brown	black, dark brown
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 light	medium light
fore femur color pattern	base dark	base dark
hind femur lightest colour	dark	dark
hind femur color pattern	entirely dark	entirely dark
hind tibia lightest colour	medium dark	medium dark
hind tibia color pattern	narrow light ring, wide light ring	narrow light ring, wide light ring
hind basitarsus lightest colour	dark	dark
hind tarsus segment 2-3 lightest colour	dark	dark
wings
middle veins lightest colour	dark, medium dark	dark, medium dark
basal veins lightest colour	medium dark	medium dark
metasoma
metasoma colour pattern	entirely dark	entirely dark
metasoma lightest colour	dark	dark
metasoma base, colour pattern	entirely dark	entirely dark
metasoma base, light spots	n.a.	n.a.
metasoma base, light band	n.a.	n.a.

Chelonus exilis in published keys

T4: Tobias, 1986

Key to the Insects of the European Part of the USSR Volume III. Hymenoptera. Part four. Chapter 16

M: Marshall, 1885

Monograph of British Braconidae. Part 1

T14: Tobias, 2010

Palearctic species of Microchelonus Szépligeti (Hymenoptera: Braconidae, Cheloninae): key to species.