Biodiversity Data Journal :
Single Taxon Treatment
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Corresponding author: Brian V. Brown (bbrown@nhm.org)
Academic editor: Torsten Dikow
Received: 05 Mar 2019 | Accepted: 26 Mar 2019 | Published: 23 Apr 2019
© 2019 Brian Brown, Maria Wong, Emily Hartop
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Brown B, Wong M, Hartop E (2019) A new white-spotted Megaselia Rondani (Diptera: Phoridae) from western North America. Biodiversity Data Journal 7: e34310. https://doi.org/10.3897/BDJ.7.e34310
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The phorid fly genus Megaselia Rondani is a large, poorly-known taxon whose species are found worldwide.
A new species of Megaselia Rondani, M. simunorum, is described from both urban and rural sites in southern California. With a large area of white colour on the posterior part of the abdominal dorsum, it closely resembles the much more common species M. sulphurizona, but M. simunorum has distinctly thicker ventral setae on the abdomen and a differently-shaped white spot.
Diptera, Phoridae, Megaselia, new species, urban biodiversity
The enormous genus Megaselia Rondani has many difficult-to-separate species, but a few seem almost immediately identifiable, such as the common western North American species Megaselia sulphurizona Borgmeier. This species, although originally described from just eight specimens from California, Washington and Idaho, USA, is widespread within western USA and is one of the most abundant species collected in urban Los Angeles by the BioSCAN project (
Amongst the many thousands of phorid flies captured by Malaise traps in the BioSCAN project were a few specimens of “another” white-spotted species. Furthermore, we found large differences in the extent of the white colour on the dorsum of M. sulphurizona and started to explore the variation within this species. We take this opportunity to describe our first, most distinctive, new white-spotted Megaselia that, based on its divergent abdominal structure, is apparently not closely related to M. sulphurizona (whose systematics we plan to study later).
The description of this species follows the reduced, table-based method we previously established (
See Table
Head |
|
SA ratio |
0.42-0.68 |
VIF position |
normal |
SPS vesicles |
present |
Palpal setae length |
long |
Labellum spinosity |
spinose |
Thorax |
|
Anepisternum |
bare |
Relative halter colour |
lighter |
# NP setae |
2 |
NP cleft |
absent |
Scutellar setae |
2+2 |
Leg |
|
ts1 palisade |
1 to 4 |
t2 palisade |
0.65-0.75 |
t3 comb bifurcate |
absent |
t3 setulae |
PD only |
f3 basal setae |
B<AV |
f3 basal setae differentiation |
absent |
Wing |
Fig. |
Wing Length (mm) |
1.49-1.88 |
Subcosta |
complete (but apically faint) |
R seta |
long |
R2+3 |
present |
Costal index |
0.36-0.45 |
Costal ratios |
2.83-3.77: 1.44-2.08: 1 |
Costal setae length (mm) |
0.10-0.14 |
Number alular setae |
3 |
Alular setae length (mm) |
0.09-0.14 |
Wing colour |
lightly infuscated/ clear |
Genitalia |
Fig. |
AT length |
AT<E |
E setation |
hairs + bristles |
General Remarks |
Membranous, semi-circular white spot on tergites 5 and 6; abdominal venter with conspicuous plumose setae coming out of sclerotised sockets. |
This species differs from all North American Megaselia, except those similar to M. sulphurizona, by the contrasting white colour of the posterior abdominal tergites. The lighter coloured halter, stronger ventral abdominal setae (compare with M. sulphuriza, Fig.
Named in memory of Dr. Patricia Bates Simun and Mr. Richard V. Simun by their daughters, Ann and Mary.
The habitats at the sites where this species was collected vary from a willow spring in an interior grassland (Wind Wolves), a sycamore/oak forest near a small creek, a coastal floodplain, an old field near the coast, to an inland urban backyard. Many involve at least some exposed water, but this might be simply a reflection of where we put our Malaise traps.
We thank the site hosts of the BioSCAN project for making this research possible, in this case, Laura Schare. The BioSCAN project was also supported by Ester Chao, the Seaver Foundation and Luis Chiappe (in his role as Senior VP of Research & Collections at the LACM). We also thank Celeste Royer of Rancho El Chorro and Landon Peppel of Wind Wolves Preserve for permission to collect. For technical support, we thank Estella Hernandez and Giar-Ann Kung of the LACM and Daisy Carrillo, Charissa Fisher, Elizabeth Perez and Brooke Wainwright of Wind Wolves Preserve.