Youngest representative of the extinct genus Microphorites in the Eocene amber of France (Diptera: Dolichopodidae: Microphorinae)
Author
Bramuzzo, Simone
Author
Nel, André
text
Zootaxa
2017
4231
4
590
594
journal article
36552
10.11646/zootaxa.4231.4.11
335b9ae0-f347-4812-abb8-fe290a0b7630
1175-5326
292650
6001304A-3DAA-4F35-A017-75B146AE4814
Microphorites erikai
sp. nov.
(
Figs 1–
4
)
Diagnosis.
Head large, very long antenna, with prolonged postpedicel, broader at base, and tapered distally; postpedicel 1.2 times longer than basal and apical articles of arista-like stylus; thorax higher than longer, strongly arched; scutellum with a pair of long apical setae plus two pairs of shorter setae; no long prescutellar setae; one long seta in notopleuron; wing with costa ending at junction with R4+5; Sc weakened towards costa; distal half of subcostal cell darkened; dark pterostigma present at fusion of first radial vein and costa; crossvein dm-cu arched into cell dm; anal lobe of wing not developed, with long setae at base of anal margin.
Description. Female.
Head rather large (
0.42 mm
long,
0.74 mm
high), eyes bare, dichoptic; facets of equal size; ocellar triangle large, three ocelli well developed; anterior pair of ocellar setae long, followed by pair of minute postocellar setae; antennae situated near middle of head; antenna long (length
0.58 mm
); scape and pedicel as long as wide, with ring of strong setae present on pedicel; postpedicel elongate,
0.28 mm
long, broader at base, tapering distally and densely covered by rather long microtrichia; arista-like stylus
0.22 mm
long, slightly shorter than postpedicel, composed of two articles, basal article very small and inconspicuous; stylus covered in short microtrichia; labellum and maxillary palpus visible, with setae; face not visible.
Thorax higher than longer (length
0.68 mm
, height
0.94 mm
), strongly arched; acrostichals tri- to biserial posteriorly, dorsocentrals uniserial, without two very long prescutellar setae; one long notopleural seta. Halter long (length
0.32 mm
) and robust. Wing hyaline,
2.11 mm
long,
0.97 mm
wide, entirely covered with microtrichia. Pterostigma (Pt) long, occupying basal 1/3 of costal section between R1 and R2+3; alula not visible; costa (C) uniformly covered with smaller setae; subcosta (Sc) closely approximated with R1, with distal half very faint, ending at costal margin, veins R2+3 and R4+5 diverging in basal half, parallel in distal half, both simple; origin of radial veins basal, at level of humeral crossvein (h); crossvein r-m in basal fourth of wing; discal medial cell (dm) anteriorly tapered, emitting three veins, i.e. M1, M2 and CuA1 ending in wing margin; crossvein bm-cu complete; basal part of M2 straight, basal medial cell (bm) more or less triangular, anal (cup) cell rounded apically.
Legs long and slender, simple, covered uniformly with setae.
Abdomen cylindrical,
1.2 mm
long, with long setae, other details not visible; female terminalia telescopic, relaxed, covered with setae, without acanthophorite spines.
Type
locality.
Farm Le Quesnoy
,
Chevrière
, near
Creil
,
Oise
department (northern
France
).
Type horizon.
Lowermost Eocene, Sparnacian (ca. - 53 Ma), level MP7 of the mammal fauna of Dormaal (
Nel et al. 1999
).
Material examined.
Holotype
PA 979, stored in the Paleontological Department,
MNHN
,
Paris
,
France
; in the same piece of amber with a large wasp and a spider.
Etymology.
Named after Erika Degasperi, girlfriend of the first author.
Discussion.
The generic diagnosis by
Grimaldi & Cumming (1999)
based on
Hennig (1971)
, with supplements by
Nel
et al
. (2004)
, is followed. Our fossil has the typical characters for
Microphorites
, e.g., antennae located near the middle of anterior margins of the eyes; arista 2-articled; anal margin of wing not making a strong curvature; three radial veins; crossvein r-m in basal fourth of wing; crossvein bm-cu complete; cell dm present; two medial veins and vein CuA1 complete; absence of acanthophorite spines on tergite 10 of the female; female abdomen telescopic.
FIGURE 1.
Microphorites erikai
sp. nov.
, holotype PA 979, photograph of habitus. Scale bar = 1 mm.
FIGURE 2.
Microphorites erikai
sp. nov.
, holotype PA 979, photograph of head. Scale bar = 0.5 mm.
FIGURE 3.
Microphorites erikai
sp. nov.
,
holotype
PA 979, photograph of wing. Abbreviations: h, humeral vein; Pt, pterostigma; Sc, subcostal vein; R1, R2+3, R4+5, branches of radius; M1, M2, branches of media; CuA, anterior cubital. Scale bar =
0.5 mm
.
FIGURE 4.
Microphorites erikai
sp. nov.
, holotype PA 979, photograph of wing base, arrow indicate series of setae on posterior margin. Scale bar = 0.5 mm.
Among the fossils currently attributed to the genus
Microphor
Macquart, 1827
, our fossil differs from the poorly known
Microphor defunctus
(
Handlirsch, 1910
)
in the smaller wings (
2.11 mm
long instead of 4.0 mm) (
Handlirsch 1910
).
Microphor eocenica
(
Meunier, 1902
)
has a short postpedicel and wing length
0.75 mm
, unlike in our fossil (
Meunier 1902
: 402; 1908).
Microphor rusticus
(
Meunier, 1908
)
has an elongate postpedicel, but not pear-shaped unlike in our fossil (
Meunier 1908: pl. 6, fig. 12
).
Within the genus
Microphorites
, the new fossil differs from all species except
M. moravicus
by the presence of a pterostigma. It differs from
M. moravicus
in few characters, viz. in the shape of the scape and pedicel. In
M. moravicus
the scape and pedicel are longer than broad, whereas in
M. erikai
sp. nov.
they are broader than long. However, the distinctive shape of the scape and pedicel in
M. moravicus
could be due to taphonomic deformation in amber. The thorax of
M. erikai
is higher than longer, unlike
M. moravicus
. The head of
M. erikai
is larger than that of
M. moravicus
. Our fossil also has long setae at the base of the anal margin of the wing, apparently unlike
M. moravicus
.
There is some uncertainty concerning the age of the amber in which the
type
specimen of
M. moravicus
is embedded. The sediment from which it was found is Paleogene in age, but the amber itself is similar to some Late Cretaceous ambers (
Tkoč
et al
. 2016
). With the present discovery, we can confirm the presence of the genus
Microphorites
in the Paleogene and consequently this taxon is present through the Cretaceous-Cenozoic crisis.