Review of unreported shorefly genera of the tribe Scatellini from the New Zealand subregion (Diptera: Ephydridae) with description of three new species
Author
Mathis, Wayne N.
Author
Zatwarnicki, Tadeusz
Author
Marris, John W. M.
text
Zootaxa
2004
622
1
27
journal article
10.5281/zenodo.158576
6a6a4828-9078-485c-99a6-0efe1998714e
11755326
158576
DC1DC389-C4C3-4059-91AF-D6AFC2BC9157
Limnellia abbreviata
(Harrison)
,
new combination
(
Figs. 24–27
)
Scatella abbreviata
Harrison 1976
: 136
.
Horning 1977
: 35
[ecology].
Mathis 1989
: 649
[Australasian/Oceanian catalog].
Mathis and Zatwarnicki 1995
: 270
[world catalog].
Diagnosis.
This species is distinguished from congeners by the following characters: Wing brachypterous; small shore fly, body length
1.35 mm
, body dark brown with grayish mottling, generally densely microtomentose.
Description.
Head:
Head ratio 0.69; mesofrons and frontoorbits dark brown to grayish brown anteromedially; parafrons grayish brown; ocellar, both verticals and single frontoorbital seta well developed and subequal; 2–3 lateroclinate setulae and a proclinate anterior setula that is slightly larger than other frontoorbital setulae; inner vertical seta inserted anterior of outer seta. Scape and pedicel gray brown; 1st flagellomere yellowish orange; arista without hairlike, dorsal branches, length subequal to combined length of pedicel and 1st flagellomere. Face golden to grayish brown; face bearing 2 lateroventroclinate setae and 5 ventroclinate setae along peristomal margin; parafacial gray. Eye ratio 0.88; genatoeye ratio 0.08; gena with 1 large, posterior seta and 2–3 setulae anterior and posterior on postgena. Palpus blackish brown.
Thorax:
Mesonotum mostly dark brown; with medial gray to whitish stripe on posterior 2/3 of scutum, slightly enlarged just before scutellum; 2 gray, elongate spots on anterior 1/3 between acrostichal and dorsocentral tracks and 1 elongate spot along dorsocentral track between setae; posterior apex of scutellum grayish; posterior notopleural seta at elevated insertion compared to anterior seta; postpronotum and posterior portion of notopleuron, extending onto supraalar area, gray; pleurae mostly brown but dorsal margin of anepisternum and especially of katepisternum gray; only 1 anepisternal seta toward dorsum of posterior margin and 1 katepisternal seta. Wing (
Fig. 27
) brachypterous, extended posteriorly to posterior margin of 2nd abdominal tergite. Legs with femora and tibiae blackish brown; basal 2 tarsomeres yellowish, apical 2–3 becoming increasingly more brownish distally.
FIGURES 24–26
. Structures of the male terminalia of
Limnellia abbreviata
(New Zealand. Snares Islands: south side of Ho Ho Bay).
24
, Epandrium, cerci, and surstylus, ventral view.
25
, Internal genitalic structures (aedeagus (shaded), phallapodeme, and gonite), ventral view.
26
, Same, lateral view.
FIGURES 27–28
. Wings of
Limnellia
species.
27
,
L. abbreviata
(New Zealand. Snares Islands: Sinkhole).
28
,
L. maculipennis
(New Zealand. Hamilton, McKenzies Bush, Dinsdale).
Abdomen:
Tergites mottled, mostly brown with gray spots or longitudinally linear marks, becoming increasingly grayer on more posterior tergites; tergites 3–5 with medial gray area and with gray surrounding brown spot just laterad of midline. Male terminalia (
Figs. 24–26
): Epandrium in ventral view (
Fig. 24
) broadly oval, lateral margins almost parallel sided, ventral margin broadly emarginate into which surstyli are based, evenly setulose; cerci with ventral angle more acute than dorsal angle but otherwise hemispherical, more setulose toward medial margin; surstyli in ventral view (
Fig. 24
) somewhat triangular, bearing longer setulae along ventral margin but with several very short setulae apically; aedeagus (shaded) in ventral view (
Fig. 25
) like a top with base wide and apex pointed, in lateral view (
Fig. 26
) almost evenly wide although dorsal and ventral margins irregular, with a subbasal, rounded notch dorsally, apex irregularly incised; phallapodeme in lateral view (
Fig. 26
) long and narrow, margin irregular, in ventral view (
Fig. 25
) Tshaped with basal bar shallowly flared, medial arm wider at articulation with base of aedeagus; gonite in lateral view (
Fig. 26
) wide basally, apical 2/3 narrow, slightly curved, apex tapered to rounded point, in ventral view (
Fig. 25
) apical projection becoming slightly wider apically but with an abruptly tapered, pointed apex; posterior projection forming an arch.
Type
material.
The
holotype
male is labeled “U. of C[anterbury]. ZOOLOGY
DEPT
. Loc.: opp. Mollymawk Inlet. SNARES IS. Hab.beating Poa astoni Date:
24I67
[
24 Jan 1967
] Coll.: P[eter].M.J[ohns] [white; details on locality, habitat, date and collector handwritten] /
HOLOTYPE
Scatella abbreviata
ɗ det. R.A.Harrison [white; handwritten].” The
holotype
is preserved in alcohol, is in good condition, and is deposited in
NZAC
. There are also five female
paratypes
that are preserved in a separate tube of alcohol (
NZAC
).
Other specimens examined.
New Zealand
. Snares Islands: South side Ho Ho Bay (on damp peat in sooty shearwater run),
11 Jan 1975
, C. J. Horning (1ɗ;
NZAC
); Sinkhole (drainage area on rock face), J. W. Early (3ɗ, 7Ψ;
AMNZ
).
Distribution.
Australasian/Oceanian:
New Zealand
(Snares Islands).
Natural history.
Horning (1977)
reported rearing this species from seepage sites on Snares Islands.
Remarks.
This is the only known brachypterous species of
Limnellia
and is distinguished from congeners by the brachypterous wing and structures of the male terminalia (
Figs. 24–26
).
When
Harrison (1976)
described this species he misinterpreted the number of lateroclinate frontoorbital setae and thus misidentified the genus. The genus
Scatella
does indeed have two frontoorbital setae, but specimens of
S. abbreviata
,
including the
holotype
, have a single welldeveloped lateroclinate seta, and thus, Harrison’s statement (1976: 136) “By definition this species is a true
Scatella
” is incorrect. Only two genera,
Limnellia
and
Scatophila
,
of the tribe
Scatellini
have a single frontoorbital seta, and species of these two genera with normally developed wings can be distinguished by the length of the costal vein (the costal vein is short in
Scatophila
,
extending only to vein R4+5, and in
Limnellia
it extends to vein M). With a brachypterous wing and greatly reduced venation, as in this species, this character is impossible to use, and we had to rely primarily on structures of the male terminalia, especially the articulated surstyli at the ventral margin of the epandrium, to make the generic assignment.