A revision of the Afrotropical genus Prytanomyia Oezdikmen, 2006 (Asilidae, Laphriinae)
Author
Londt, Jason G. H.
Author
Dikow, Torsten
text
African Invertebrates
2017
58
2
39
52
http://dx.doi.org/10.3897/AfrInvertebr.58.13294
journal article
http://dx.doi.org/10.3897/AfrInvertebr.58.13294
2305-2562-2-39
E1117C7D3A954B449FE4D49093A76961
Prytanomyia kochi (Lindner, 1973)
comb. n.
Figs 1-2, 3-4, 5-10, 11, 12-16, 17
Laphystia kochi
Lindner, 1973: 74 (fig. 1 Entire
♀
). http://zoobank.org/F60777CD-C8F2-43E0-9D4C-DAF4EF624495
Laphyctis kochi
(Lindner, 1973),
Londt 1988
: 513.
Prytania albida
Oldroyd, 1974: 112 (fig. 105 Entire
♂
) syn. n.http://zoobank.org/79557160-03D9-412F-9799-90DD93FF1EEB
Redescription.
Based on all available material. General appearance as in Figs 1-10. Note: Slight sexual dimorphism occurs in the colour of antennae and legs and pubescence of abdominal tergites.
Head: Dark red-brown, colour masked by strong silver pruinescence, shiny white setose. Antennae mostly dark red-brown, scape red-brown in
♂
, dark brown-yellow in
♀
, pedicel brown-yellow, postpedicel and stylus dark red-brown, fine silver pruinose. Scape strongly white setose ventrally, pedicel weakly white setose. Postpedicel with fairly narrow terminal cup-shaped stylus with oblique opening and enclosing a seta-like sensory element. Segmental length ratios (scape (as 1): pedicel: postpedicel: style) - 1: 0.5: 2.2: 0.5. Eye smoothly oval in lateral view, ommatidia of fairly uniform size over entire surface. Face dark red-brown, colour masked by strong silver pruinescence. Width of one eye: face ratio 1: 1.4 (face clearly wider than eye - Figs 4, 7-8). Face with gently convex profile, projecting weakly at mid height. Mystacal setae numerous (no obvious macrosetae), shiny white, covering most of face although more sparsely dorsally. Frons and vertex dark red-brown, colour masked by shiny silver pruinescence, extensively white setose. Ocellar tubercle weakly protuberant, fine white setose (no obvious macrosetae). Postocular (occipital) region dark red-brown, colour masked by strong silver pruinescence. Occiput with rows of c. 15 white macrosetae dorsally behind each eye and many fine, shiny white setae. Palpi dark red-brown, 2-segmented, weakly fine white setose. Proboscis straight, circular in cross-section, shiny dark red-brown, fine white setose proximally and distally.
Thorax: Dark red-brown, uniformly strongly silver pruinose, white setose. Pronotum dark red-brown, silver pruinose, white setose. Mesonotum dark red-brown, entirely silver pruinose, uniformly fine white setose. Dorsocentral setae poorly developed and mostly evident postsuturally. Lateral macrosetae white, 3 npl, 2-3 spal, 2-3 pal. Scutellum dark red-brown, fine silver pruinose (weakly anteriorly and along posterior margin), c. 20 fine, white, erect apical scutellar macrosetae. Pleura dark
red-brown
, entirely silvery pruinose, white setose. Katatergal macrosetae, numerous, moderately developed, white. Anatergites uniformly strongly silver pruinose, asetose. Postmetacoxal area membranous. Legs: Coxae dark red-brown, silver pruinose, white setose. Femora, tibiae and tarsi fairly uniformly orange, except for dorsal parts of femora and metathoracic tibiae in
♂
which are commonly partly red-brown, shiny white setose. Claws well developed, black with brown-orange basal parts. Empodium white, straight, slightly shorter than claws. Pulvilli pale yellow, poorly developed, about
1/2
as long as claws. Wings (Fig. 11): length measured from humeral crossvein to tip, breadth at widest level: Males (10) 3.9
x
1.4 - 5.2
x
2.1 mm
(mean 4.6
x
1.7 mm
), females (10) 4.6
x
1.7 - 6.9
x
2.6 mm
(mean 5.4
x
2.1 mm
). Females on average slightly bigger than males. Venation: Marginal cells open (notably r1) except for m3 and cua, which are closed and stalked. Vein M3 unusually weakly developed at base (enclosing discal cell d). Veins pale yellow anteroproximally, brown posterodistally, membrane unstained, transparent, lacking microtrichia. Costa (C) apparently
terminating
at junction of veins CuA and CuP with wing margin. Cell cup and alula with weak bordering microsetae.
Abdomen: Dark red-brown to black, white setose, silver pruinose. Tergites (
♂
with 6 well-developed and clearly evident, others reduced and hidden from view underneath T6;
♀
with 8 visible tergites) dark red-brown to black, white setose, especially laterally, silver pruinose posterolaterally, apruinose anteromedially. T1-6 with white discal macrosetae (progressively diminishing in number from T1 to T6). Sternites red-brown with
brown-yellow
posterior margins, fine white setose, fine dull silver pruinose.
♂
terminalia (Figs 12-14): Genital bulb rotated c. 15-45° clockwise or anticlockwise. T7-8 and S7-8 reduced and poorly defined. Epandrium large, in dorsal view almost twice as long as broad and widely bilobed in distal quarter (Fig. 12) and with minor projections either side of base of proctiger. Proctiger short, fairly broad, projecting only slightly beyond distal epandrial margin in dorsal view. Hypandrium in ventral view subcircular (Fig. 14),
poorly
defined, almost transparent, margins difficult to appreciate; in lateral view bent at an almost right angle proximally such that it is clearly separated from the gonocoxites (Fig. 12). Gonocoxites well developed, clearly bilobed, broader than epandrium in lateral view (Fig. 12) and more than half as long as epandrium. Gonostyli laterally compressed, subdivided into two lobes, a narrow dorsal lobe with darkly sclerotized ventrally hooked terminal point, and a broad S-shaped ventral lobe with dorsally hooked distal end. Aedeagus with long, gently sinuous distal shaft reaching level of proctiger, tip rounded (details difficult to see).
♀
terminalia (Fig. 15): Relatively broad and somewhat dorsoventrally flattened. Segments 1-6 well developed, segments 7-8 reduced, but clearly evident. Subgenital plate moderately well-developed, broader than long, with undulating, distal margin displaying two pairs of lobes separated by a depressed area. Proctiger with dorsal lamellae wider than ventral lamellae. Note: On dissection the abdomen was found to contain a few semi-spherical eggs with a diameter of c.
0.5 mm
(Fig. 16).
Notes on original descriptions.
Laphystia kochi
:
Lindner (1973)
studied only three female specimens, one from Gobabeb, and two from Swakopmund (localities well represented by material in the
NMSA
and
USNM
). Both were collected in February, as was the
NMSA
and
USNM
material. His description, in German, is detailed and agrees in all important ways with that presented above. Interestingly Lindner fails to mention the poorly developed pulvilli although these are evident in his photograph of one of the specimens. Lindner did not designate a holotype and so his specimens must be regarded as syntypes. Lindner named the species for Dr Charles Koch, founder of the Gobabeb Research Station in Namibia, where he collected a specimen.
Prytania albida
:
Oldroyd's
(1974)
description is good and there is no doubt that the material available from several museums agrees fully with his types. The type locality is Swakopmund from which many specimens have subsequently been collected.
Type material.
Lindner (1973)
listed his material of
Laphystia kochi
as '
1♀
Gobabeb, SWA,
2-8.II.1970
;
2♀
Swakopmund,
29
-30.II.1970'
, but the two specimens from Swakopmund are labelled as having been collected on different days as shown below. As Lindner failed to designate a holotype and in order to preserve stability we hereby designate one of the three female specimens as Lectotype (Figs 3-4). The other two specimens are considered paralectotypes.
Lectotype
.
NAMIBIA
:
1♀
'
Sovakopmund [misspelling of Swakopmund
c.
22°41'18"S
,
14°32'02"E
,
10m
] SWA. /
29-
30.2. 1970
/
Lindner
leg.' [blue], '
Laphystia
/
kochi
Lind. / Lindner det.' [white], 'Syntype /
Laphystia
/
kochi
Lind. / Det. J. Londt.',
'
AAM-007677
'
(
SMNS
)
.
Paralectotypes
.
NAMIBIA
:
1♀
'
Swakopmund
/ SWA.
31.1.1970
/
Lindner
leg.' [blue], '
Laphystiella
/
kochi
Lind. / Lindner det.', 'Syntype /
Laphystia
/
kochi
Lind. / Det. J. Londt.',
'
AAM-007678
'
(
SMNS
)
;
1♀
'
Gobabeb
[c.
23°33'47"S
,
15°02'25"E
395m
] SWA. /
2-
9.2.1970
/
Lindner
leg.' [blue], '
Laphystia
/ sp nov. / det H. Oldroyd 1970' [white], '
Laphystia
/
kochi
Lind. / Lindner det.', 'Syntype /
Laphystia
/
kochi
Lind. / Det. J. Londt.',
'
AAM-007678
'
(
SMNS
)
.
Other previously recorded material. Types and other specimens of
Prytania albida
Oldroyd, 1974, in the
BMNH
, are as follows:
Holotype
.
NAMIBIA
:
1♂
'Holotype'
, 'S.W. Africa (25),
Swakopmund
[c.
22°41'18"S
,
14°32'02"E
,
10m
],
26
-30.i.1972'
, '
Southern African Exp. B.M.
1972
-1'
, '
Prytania albida
Old. det. H. Oldroyd
Holotype'
,
'
NHMUK010292241
'
.
Paratypes
.
ANGOLA
:
1♀
'Angola (A15)
R. Giraul
[c.
15°04'43"S
,
12°17'28"E
,
65m
]
10 mls. NE. Mocamedes
27
-29.ii.1972'
, '
Southern African Exp. B.M.
1972
-1'
,
'
NHMUK010292263
'
;
3♀
'
Paratype
, '
Angola
(A8)
2 mls. S. Mocamedes [= Namibe
c.
15°10'02"S
,
12°09'32"E
,
5m
]
24
-25.ii.1972'
, '
Southern African Exp. B.M.
1972
-1'
, 'Paratype
Prytania albida
Old. det. J.E. Chainey 1986', '
NHMUK010292251
,
NHMUK010292256
,
NHMUK010292259
'
;
2♂
2♀
'
Paratype
, '
Angola
(A10)
R. Curoca 7 mls. NE
. [c.
15°43'52"S
,
11°55'27"E
,
10m
]
P. Alexandre
25
-26.ii.1972'
, '
Southern African Exp. B.M.
1972
-1'
, 'Paratype
Prytania albida
Old. det. J.E. Chainey 1986', '
NHMUK010292250
,
NHMUK010292253
,
NHMUK010292257
,
NHMUK010292258
'
;
2♀
'
Angola
(A9)
Porto Alexandre [=
Tombua
c.
15°48'15"S
,
11°50'42"E
,
10m
]
25.ii.1972
', '
Southern African Exp. B.M.
1972
-1'
, '
NHMUK010292261
,
NHMUK010292262
'
;
NAMIBIA
:
3♂
7♀
'
Paratype
, 'S.W. Africa (25)
Swakopmund
[as for holotype]
26
-30.i.1972'
, '
Southern African Exp. B.M.
1972
-1'
, 'Paratype
Prytania albida
Old. det. J.E. Chainey 1986',
'
NHMUK010292241-NHMUK010292249
,
NHMUK010292254
-
NHMUK010292255
'
;
1♂
'
Paratype
, 'W. Africa (24)
Walvis Bay
[c.
22°57'22"S
,
14°30'29"E
,
10m
]
25
-26.i.1972'
, '
Southern African Exp. B.M.
1972
-1'
, 'Paratype
Prytania albida
Old. det. J.E. Chainey 1986',
'
NHMUK010292252
'
;
1♂
'S.W. Africa (23)
Homeb
[c.
23°38'12"S
,
15°10'55"E
,
435m
]
10 mls. ESE Gobabeb
23
-25.i.1972'
, '
Southern African Exp. B.M.
1972
-1'
,
'
NHMUK010292260
'
.
Previously unrecorded material examined:
NAMIBIA
:
Erongo
:
2♂
14♀
'South West Africa 2113Ba / Swakopmund Dist.
Ugab / River Mouth
[c.
21°11'13"S
,
13°37'47"E
],
8 m
.
7.ii.1974
/
ME & BJ Irwin
,
vegetated / sand mounds nr.
coast'
(♂
NMSADIP08395
,
NMSADIP71654
♀
NMSADIP08374
,
NMSADIP08389
,
NMSADIP71655-66
) (
NMSA
)
;
5♂
15♀
Namib-Skeleton
Coast National Park
,
off C34 N Cape Cross
,
21°43'40"S
,
013°58'48"E
,
3 m
,
2012-02-02
,
coastal vegetated dunes
, perching on sand,
Dikow, T.
(
USNMENT00832290-1
,
USNMENT00832293-5
,
00832297-310
,
USNMENT00832312
) (
USNM
)
;
4♂
3♀
Namib-Skeleton Coast National Park
,
N Omaruru River mouth
,
22°05'19"S
,
014°15'09"E
,
8 m
,
2012-02-02
,
coastal vegetated dunes
, perching on sand,
Dikow, T.
(
USNMENT00832311
,
USNMENT00832313-8
) (
USNM
)
;
1♂
Swakopmund
,
22°41'09"S
,
014°31'51"E
,
1990-02-12
,
Schwartz, M.
(
COGG
)
;
28♂
27♀
'South West Africa 2214Da /
Swakopmund Dist.
Swakop / River Mouth
[c.
22°41'21"S
,
14°31'36"E
],
8 m
.
9.ii.1974
/
ME & BJ Irwin
,
coastal / and riverbed
dunes'
(♂
NMSADIP71667-94
, ♀
NMSADIP08327
,
NMSADIP08390
,
NMSADIP71695-719
) (
NMSA
)
;
5♂
7♀
Swakopmund, S side
Swakop River
mouth,
22°41'33"S
,
014°31'37"E
,
9 m
,
2012-02-03
,
sandy river bed and vegetated dunes
, perching on sand,
Dikow, T.
(
USNMENT00832319-29
,
USNMENT00832334
,
USNMENT00832338
) (
USNM
)
;
1♂
3♀
B2 Swakopmund-Walvis Bay
,
22°44'42"S
,
014°31'27"E
,
6 m
,
2012-02-04
,
coastal vegetated dunes
, perching on sand,
Dikow, T.
(
USNMENT00832331
,
USNMENT00832335-6
,
USN
MENT
00832343
) (
USNM
)
;
6♂
13♀
'South West Africa 2214Dc /
Swakopmund Dist.
12 km
. N.
Walvis Bay
[c.
22°51'43"S
,
14°32'35"E
],
3 m
.
10.ii.1974
/
ME & BJ Irwin
,
vegetated / mounds and
dunes'
(♂
NMSADIP08397
,
NMSADIP71720-24
, ♀
NMSADIP08329
,
NMSADIP08380
,
NMSADIP71725-35
) (
NMSA
)
;
1♀
Walvis Bay
,
22°57'22"S
,
014°30'29"E
,
1990-02-22
,
Schwartz, M.
(
COGG
)
;
5♀
Namibia
Walvisbaai [= Walvis Bay]
,
5 km
S
(c.
23°01'02"S
,
014°27'54"E
),
5 m
/
22.xi.1996
,
low dunes
,
M.E. Irwin
(
INHS-713233-5
) (
INHS
)
;
1♂
Gobabeb, Namib Desert Research Station
,
23°33'37"S
,
015°02'26"E
,
1983-11-17
,
Moore, A.
(
USNMENT00802354
,
USNM
)
;
1♂
4♀
'South West Africa 2315Ca /
Namib Desert Park, Kuiseb / River at Gobabeb
[c.
23°33'47"S
,
15°02'25"E
].
400m
. /
12.ii.1974
,
ME & BJ Irwin
/
Riverine forest and
sand'
(♂
NMSADIP71736
, ♀
NMSADIP08388
,
NMSADIP71737-9
) (
NMSA
)
;
1♀
Namib-Naukluft Park
,
Namib Desert Research Station, Kuiseb River
,
23°33'45"S
,
015°02'38"E
,
420 m
,
22.xi.1996
,
M.E. Irwin
(
INHS-33542
) (
INHS
)
;
1♂
'SWA
Kuiseb R.
[probably as above] /
9.xii.1976
/
AB
Cunningham'
(
NMSADIP08400
) (
NMSA
)
;
1♀
Namib-Skeleton Coast National Park
,
Gobabeb, Kuiseb riverbed
,
23°33'47"S
,
015°02'22"E
,
396 m
,
2012-02-06
, perching on sand,
Dikow, T.
(
USNMENT00832344
,
USNM
)
;
5♀
Namib-Skeleton Coast National Park
,
Homeb
,
23°38'34"S
,
015°10'55"E
,
445 m
,
2012-02-06
,
dune
, perching on sand,
Dikow, T.
(
USNMENT00832332
,
USNMENT00832337
,
USNMENT00832340
,
USNMENT00832342
,
USNMENT00832346
) (
USNM
)
;
1♀
Namib-Skeleton Coast National Park
,
Homeb
,
Kuiseb riverbed
,
23°38'34"S
,
015°11'21"E
,
430 m
,
2012-02-06
, perching on sand,
Dikow, T.
(
USNMENT00832341
) (
USNM
)
;
Karas
:
6♂
13♀
'South West Africa 2615Ca /
Luederitz
Dist.
Agate / Beach
[c.
26°36'23"S
,
15°10'37"E
],
10 km
. N.
Luederitz
,
3 m
. /
ME & BJ Irwin
.
18.ii.1974
/
on coastal vegetated
dunes'
(♂
NMSADIP71740-5
, ♀
NMSADIP08386
,
NMSADIP71746-57
) (
NMSA
)
.
Distribution, phenology and biology. The distribution of
Prytanomyia
is illustrated in Fig. 17. With exception of the Gobabeb and Homeb records all can be considered coastal. Gobabeb and Homeb are situated inland on the east side of the Namib desert dunes, but on the banks of the Kuiseb River which eventually runs into the Atlantic ocean at Walvis Bay. At Gobabeb, specimens were caught in the dry Kuiseb riverbed (Fig. 22) by M. Irwin and the junior author (other collecting events lack habitat detail) and this environment is similar to the Swakop and Omaruru river mouths (Figs 19-20) on the coast. The majority of specimens at Homeb though were collected on the large dunes adjacent to the Kuiseb riverbed (Fig. 21, only a single specimen in the dry Kuiseb riverbed), which is quite different from the coastal dunes at river mouths. The small sand mounds (Fig. 18) from which M. Irwin and the junior author collected the species (other coastal collecting events lack habitat detail) are also quite a different habitat from the larger sand deposits or dunes at river mouths. It can be hypothesized that the species will inhabit the Namib dune fields away from the coast that exist between southern Angola and
Luederitz
in southern Namibia and of which the internal dunes and intervening valleys have rarely been sampled for insects.
The
majority of collecting records are for February (179) with a few records (15) for late January. Eight specimens were collected in mid- to late November (at Gobabeb and south of Walvis Bay) and a single specimen was collected in early December (at Gobabeb). Although the number of specimens included in this study is high (203), most were collected over very limited periods of time as well as only during a few collecting events, and so the species may be active for far longer than presently appreciated. Material bearing information relating to the known habitat of
P. kochi
strongly suggests that these flies are associated with vegetated sand mounds and dunes or sandy, dry, riverbeds (Figs 18-22). The highly reduced pulvilli support this contention and it is predicted that these flies rest almost entirely on sandy surfaces much like other species with poorly developed pulvilli, or entirely lacking these structures (see discussion in
Londt and Copeland 2017
).
Virtually nothing is known of the biology of
Prytanomyia
and only three prey records are available. Three female specimens are pinned together with their tiny prey -
Diptera
(2),
Hymenoptera
(1). Of the 201 recorded specimens, 69 (34%) are males and 132 (66%) females, suggesting a possible imbalance in sexual representation.
Figures 1-2.
Prytanomyia kochi
female perching on small, vegetated coastal sand mounds/dunes north of Cape Cross, Namibia (
21°43'40"
S
,
013°58'48"
E
, see Fig. 18): 1 dorsolateral (Morphbank #860918) 2 (#860920). Photographs: T. Dikow.
Figures 3-4.
Prytanomyia kochi
Lectotype
♀
(
SMNS
, AAM-007677): 3 lateral 4 head anterodorsal.
Figures 5-10.
Prytanomyia kochi
:
5 female
(USNMENT00832290), dorsal (Morphbank #860900) 6 same, lateral (#860902) 7 same, head anterior (#860904)
8 male
(USNMENT00832294) head anterior (#860893) 9 same, dorsal (#860895) 10 same, lateral (#860897). Scale bars:
5 mm
.
Figure 11.
Prytanomyia kochi
female wing (NMSADIP71708).
Figures 12-16.
Prytanomyia kochi
(Swakop River Mouth) terminalia:
12 male
(NMSADIP71694), dorsal 13 same, lateral 14 same, ventral
15 female
(NMSADIP08390), ventral
16 egg
. Scale bar:
1 mm
.
Figure 17. Map of southern Africa with elevational relief and distribution of
Prytanomyia kochi
. Type locality with square symbol (SimpleMappr 7675).
Figures 18-22.
Prytanomyia kochi
habitats (all in Namibia): 18 small, vegetated coastal sand mounds/dunes north of Cape Cross (
21°43'40"
S
,
013°58'48"
E
) 19 coastal river mouth dunes north of Omaruru River mouth (
22°05'19"
S
,
014°15'09"
E
) 20 coastal river mouth dunes south of Swakop River mouth (
22°41'33"
S
,
014°31'37"
E
) 21 high dunes at Homeb (
23°38'34"
S
,
015°10'55"
E
) 22 dry Kuiseb riverbed with adjacent high dunes at Gobabeb (
23°33'47"
S
,
015°02'22"
E
). Photographs: T. Dikow.