A new stiletto fly genus from South America (Diptera: Therevidae: Agapophytinae)
Author
Irwin, Michael E.
Author
Winterton, Shaun L.
text
Zootaxa
2020
2020-03-17
4751
2
276
290
journal article
10.11646/zootaxa.4751.2.4
e3adbec8-2861-49f8-b7a2-39f1bdcbb493
1175-5326
3713094
31F0F048-6F6E-416B-B687-4160348D6705
Sigalopella
gen. n.
(Figs 1–14)
urn:lsid:zoobank.org:act:
E2A3B029-11D7-4F43-A091-62641A6A197A
Type-species:
Sigalopella rufifemoralis
sp. n.
(here designated).
Diagnosis
. Predominantly glossy black-bodied flies with long antennae, setal pile longer in male. Body length: 6.5–8.0 mm (male), 7.0–
9.5 mm
(female). Head relatively broad, wider than thorax; male eyes contiguous dorsomedially; male with single row of postocular macrosetae dorsally; face distinctively rounded to bulbous laterally, glabrous except for silver pubescence along eye margin, parafacial setae present, more extensive and elongate in male; antenna longer than head; scape narrow elongate, longer than flagellum; flagellum tapered cylindrical; extensive black setal pile along all antennal segments, especially scape and pedicel; palpus incrassate; prosternum without setal pile; metanepisternum without postspiracular setal patch; 1–3 dorsocentral macrosetae; one pair of scutellar macrosetae; posterior lateral surface of midcoxa lacking setal pile; velutum patches absent on femora and gonocoxites; legs with distinct short black setal pile, denser on tibia and tarsi; hind leg relatively longer than fore and mid legs; single anteroventral seta present apically on hind femur; wing mostly uniform dark infuscate, paler posteriorly, cell
r
1
hyaline basally; costal vein circumambient around wing margin, wing cell
m
3
open, vein R
1
with setae absent; abdominal tergite 2 with setae uniform in size medially; male genitalia with inner gonocoxal process well developed; gonocoxites with medial atrium lacking; hypandrium small; aedeagus with distiphallus narrow apically, dorsal apodeme of parameral sheath broadly triangular, ventral apodeme narrowly forked; female genitalia with acanthophorite setae as two sets (A1 & A2), A1 usually enlarged; three spermathecae present, ducts joining to spermathecal sac duct; spermathecal sac present and simple in shape (not lobed).
Included species
.
Sigalopella armeniaca
sp. n.
,
S. ammophila
n. sp.
,
S. nigrofemoralis
sp. n.
and
S. rufifemoralis
sp. n.
Etymology
.
Sigalopella
is derived from the Greek
sigaloma
– smooth, polished, and
pellos
– dusky, dark, for the dark polished appearance of members of this genus; gender is feminine.
Comments
.
Sigalopella
gen. n.
is known only from central
Chile
(Fig. 14).
Pachyrrhiza
,
Entesia
and
Mela- nothereva
form a monophyletic clade of South American
Agapophytinae
called the
Entesia
genus-group (
sensu
Winterton
et al
., 2016
), which also includes this new genus. We consider
Sigalopella
gen. n.
as the likely sister to
Pachyrrhiza
. Amongst the South American
Agapophytinae
, these two genera share characteristics such as a protruding rounded parafacial with parafacial setae present, and the male post-ocular setae elongate and arranged in a single row dorsally.
Sigalopella
gen. n.
can be easily recognised by the overall black coloration, narrow elongate antennae, absence of setal pile on the prosternum and incrassate palpi.
Pachyrrhiza
has a notably short and bulbous antennal scape (
cf
. elongate and narrow in
Sigalopella
gen. n.
) and an abundance of macrosetae on the head and scutum. Most
Pachyrrhiza
have mottled or hyaline wings, never uniformly infuscate like in
Sigalopella
gen. n.
Species of
Sigalopella
gen. n.
are easily separated from each other using external characters such as colour and vestiture, as well as head and antennal shape; male and female genitalia is remarkably uniform amongst all members of the genus and is not useful for differentiating species in either sex.