A new species of Cretevania Rasnitsyn, 1975 (Hymenoptera: Evaniidae) from the mid-Cretaceous Kachin amber
Author
ROSSE-GUILLEVIC, SIMON
Author
JOUAULT, CORENTIN
text
Palaeoentomology
2023
2023-06-14
6
3
242
249
http://dx.doi.org/10.11646/palaeoentomology.6.3.6
journal article
10.11646/palaeoentomology.6.3.6
2624-2834
8073076
63C918C3-778D-4D90-AA27-562D8F9A2902
Cretevania kachinensis
sp. nov.
(
Figs 1–3
)
urn:lsid:zoobank.org:act:
3C7621BE-F2E1-4F5C-8A47- E53C3746
CAD
8
Material.
Holotype
IGR
.BU-075 (in an amber piece measuring 11 × 6 ×
1 mm
, with a few stellate hairs and a Thysanoptera), deposited in the amber collection of the
Geological Department
and
Museum
of the
University of Rennes
,
France
(
IGR
).
Etymology.
The species name refers to the state of the
type
locality of the amber piece.
Diagnosis.
Antennae with 10 flagellomeres; scape shorter than head length; pedicel very short, about as long as wide. Forewing with pterostigma elongate, longer than 2r-rs; pterostigma base basad of 2Rs middle; vein 1Rs about 0.25× as long as 1M and subvertical to R; 1+2r cell 1.4× as long as 3r cell; 2r-rs 2.25× as long as pterostigma width; 2Rs slightly longer than 3Rs; 1m-cu anteriad of 2Rs+M fork, angle between 1m-cu and 2Cu
ca
. 110°; 1mcu cell about 1.6× as long as wide; 2rm cell triangular,
ca
. 1.8× as long as 1mcu cell; 2r-m spectral (outlined by the absence of microtrichia); 1cu-a distinctly postfurcal; 2cua cell rectangular (1cu-a and 2cu-a complete, and A slightly overpassing 2cu-a); 2cu-a straight; 2m-cu absent; A not fused with 2cu-a.
Locality and horizon.
Noije Bum Hill, Hukawng Valley,
Kachin State
,
Myanmar
; upper Albian to lower Cenomanian, mid-Cretaceous.
Description.
Male. Body mostly black (complicating the observation of mesosomal structures). Total length
ca
.
3.2 mm
.
Head
ca
.
0.38 mm
long,
0.5 mm
high (0.76× as long as high), covered with minute erected setae. Eyes kidneyshaped
ca
.
0.15 mm
long,
ca
.
0.22 mm
high (0.68× as long as high). Antennae with 12 antennomeres,
ca
.
1.12 mm
long and
ca
.
0.05 mm
wide; scape short and thick, shorter than head length; pedicel very short, about as long as wide; flagellomeres cylindrical, distinctly longer than wide, gradually and slightly thickening and shortening towards apex, except apical one (flagellomere I
ca
.
0.11 mm
long, penultimate
0.07 mm
long, and apical one
0.12 mm
long); distal flagellomere acuminate. Clypeus short and lenticular, with a sigmoidal profile. Mandibles robust, bases apparently broader than clypeus length. Maxillary palpus with at least four palpomeres, length of measurable part
0.23 mm
, apical palpomere acuminate. Labial palpus not visible.
FIGURE 1.
Cretevania kachinensis
sp. nov.
, holotype IGR.BU-075.
A
, Habitus in left lateral view.
B
, Habitus in right lateral view. Scale bars = 500 µm (
A
) and 750 µm (
B
).
Mesosoma
0.98 mm
long,
0.5 mm
high covered with minute erected setae; long, white and erected setae present ventrolaterally (on mesopleuron and propleuron). Mesopleuron with anepisternum and katepisternum delineated by a conspicuous carina. Propodeum and metapleuron areolate-rugose. Mid and hind legs close together, distinctly separated from forelegs (distance between fore and mid coxae
0.04 mm
). Forelegs: coxa
0.24 mm
long,
0.1 mm
wide; trochanter
0.16 mm
long,
0.08 mm
wide; femur
0.38 mm
long,
0.06 mm
wide; tibia setulose
0.5 mm
long,
0.03 mm
wide; tarsus
0.48 mm
,
0.03 mm
wide, basitarsomere slightly shorter than remaining tarsomeres lengths combined, all others subequal in length. Mid-legs: coxa
0.37 mm
long,
0.04 mm
wide; trochanter
0.23 mm
long,
0.04 mm
wide; femur
0.53 mm
long,
0.07 mm
wide; tibia setulose
0.52 mm
long,
0.04 mm
wide; tarsus
0.51 mm
long,
0.03 mm
wide, basitarsomere about same length as tarsomeres II– IV, tarsomere V slightly longer than tarsomere IV. Hindlegs: coxa very robust (strongly enlarged)
0.39 mm
long,
0.18 mm
wide; trochanter
0.25 mm
long,
0.09 mm
wide; femur very robust (strongly enlarged) and setulose,
0.53 mm
long,
0.18 mm
wide; tibia widening after midlength, distinctly setulose along dorsal edge and punctate,
0.7 mm
long,
0.1 mm
wide; tarsus
0.75 mm
long,
0.04 mm
wide, basitarsomere slightly shorter than remaining tarsomeres lengths combined, all others subequal in length. Tibial spurs formula 1-2-2; tarsal claws simple; arolium present.
Forewing hyaline, covered with microsetae,
1.7 mm
long and
0.67 mm
wide; costal area at most as broad as pterostigma; pterostigma fully sclerotized, infuscate, darker basally; 1Rs extremely short, strongly angled with 1M; 1Rs+M longer than 2r-rs, 0.4× as long as 2Rs; 2Rs long and curved; 2r-rs reaching Rs slightly anteriad 2rm; 3Rs slightly curved reaching wing margin well before apex; R continuing along wing margin distad cell 3r apex; M+Cu basal half spectral; cell 1mcu trapezoidal, longer than wide, with sides 1Rs+M and 2Cu subparallel (both veins straight); M geniculate, angle between 2M and 3M
ca
. 160°; 2M curved; 3M slightly sigmoidal, longer than 2M; A straight; 1Cu slightly longer than 1Rs, slightly angled with 2Cu; 2Cu shorter than 1Rs+M; 3Cu long, distal third curved towards posterior wing margin; cell 2cua shorter and thinner than cell 1mcu; Rs, M and Cu distal abscissae reaching wing margin. Hind wing small (apex nearly aligned with 2Rs+M), hyaline, covered with microsetae; R with three(?) hamuli.
Metasoma
2.11 mm
long,
0.55 mm
wide; petiole swelled ventrally in distal third, 0.75× as long as rest of metasoma, 0.8× as long as mesosoma; second metasomal segment sub-triangular (in lateral view), 0.44× as long as petiole. Parameres exerted and lobe-shaped.
Remarks.
Cretevania kachinensis
sp. nov.
differs from the two other species close to where it keys out because of wing venation characters. The new species differs notably from
C
.
vesca
in having 2rm cell
ca
. 1.8× as long as 1mcu cell, 1Rs 0.25× as long as 1M and subvertical to the latter, pterostigma base basad midpoint of 2Rs, 2r-rs 2.25× as long as pterostigma width, 1+2r cell 1.4× as long as 3r cell, 2Rs slightly longer than 3Rs, 1m-cu located basad 2Rs+M fork, angle between 1m-cu and 2Cu of
ca
. 110°, 1mcu cell about 1.6× as long as wide, 1cu-a postfurcal, 2cua cell closed (1cu-a and 2cu-a complete, and A slightly overpassing 2cu-a).
FIGURE 2.
Cretevania kachinensis
sp. nov.
, holotype IGR.BU-075.
A
, Head in right laterofrontal view (arrows pointing to the flagellomeres).
B
, Detailed lateral left view of mesosoma (arrows point to the limit between anepisternum and katepisternum).
C
, Detailed lateral left view of legs (arrows pointing respectively to mid and hind tibial spurs).
D
, Detailed lateral left view of metasoma (arrow pointing to swollen petiole). Scale bars = 250 µm (
A
,
D
), 100 µm (
B
), 500 µm (
C
).
Cretevania kachinensis
sp. nov.
differs from
C
.
alcalai
because of the presence of the vein r-m (spectral,
vs
. absent? in
C
.
alcalai
), the 2cu-a and A distinct with 2cu-a straight (
vs
. fused to form a broadly curved vein), and the vein 1Rs subvertical (strongly inclined towards wing base in
C
.
alcalai
).
The new species differs from the two other species known from the mid-Cretaceous Burmese amber (
C
.
tenuis
and
C
.
bechlyi
) because of its unique combination of wing venation characters but also owing to its antennae and eye shape.
Cretevania kachinensis
sp. nov.
differs from
C
.
tenuis
in having 2r-rs much shorter than its distance to pterostigma base (about as long as its distance to pterostigma base in
C
.
tenuis
),
i
.
e
., in having a much longer pterostigma.
C
.
tenuis
also has bigger and rounder eyes, 2Rs+M longer, and a thinner and longer 3r cell.
It is worth noting that
Cretevania kachinensis
sp. nov.
is also, with
C
.
bechlyi
, the only other member of the genus bearing 10 flagellomeres (
i
.
e
.,
11 in
other
Cretevania
species
). However, the scape and pedicel relative sizes are clearly different between the two species (scape very long and pedicel very short in
C
.
bechlyi
, more homogenous in size in
Cretevania kachinensis
sp. nov.
).
C
.
bechlyi
also has a 2cu-a subequal in length to 1m-cu (smaller than 1m-cu in
Cretevania kachinensis
sp. nov.
), and a petiole 0.5× as long as mesosoma (0.8× as long as mesosoma in
Cretevania kachinensis
sp. nov.
).
C
.
bechlyi
also has a distinctly spatulate wing shape,
i
.
e
., area under 3Cu wide and expanded (the wing is more slender in
Cretevania kachinensis
sp. nov.
,
i
.
e
., not expanded under 3Cu).