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Iceland, near geothermal area - September 2024

Anyone have any ideas on possible genera for this one?


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Species list of Anthomyiidae for Iceland from National Institute only lists the following 10 genera as known to be here.

Which genera can be ruled out ? ( if any ) :

Alliopsis sepiella (Zetterstedt, 1845)

Botanophila betarum (Lintner, 1883)
Botanophila fugax (Meigen, 1826)
Botanophila profuga (Stein, 1916)
Botanophila rubrigena (Schnabl, 1915)
Botanophila silvatica (Robineau-Desvoidy, 1830)
Botanophila tuxeni (Ringdahl, 1953)

Delia angustifrons (Meigen, 1826)
Delia echinata (Séguy, 1923)
Delia fabricii (Holmgren, 1872)
Delia platura (Meigen, 1826)
Delia radicum (Linnaeus, 1758)
Delia setigera (Stein, 1920)

Egle lyneborgi Ackland & Griffiths, 2003
Egle minuta (Meigen, 1826)
Egle pilitibia (Ringdahl, 1918)

Fucellia fucorum (Fallén, 1819)
Fucellia maritima (Haliday, 1838)

Hydrophoria albiceps (Meigen, 1826)

Lasiomma picipes (Meigen, 1826)
Lasiomma seminiditum (Zetterstedt, 1845)

Pegomya bicolor (Wiedemann, 1817)
Pegomya fulgens (Meigen, 1826)
Pegomya furva Ringdahl, 1938
Pegomya icterica (Holmgren, 1873)
Pegomya notabilis (Zetterstedt, 1846)

Pegoplata infirma (Meigen, 1826)

Zaphne ambigua (Fallén, 1823)
Zaphne brunneifrons (Zetterstedt, 1838)
Zaphne divisa (Meigen, 1826)
Zaphne frontata (Zetterstedt, 1838)
Zaphne subarctica (Ringdahl, 1918)

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...to show better protruding mouth edge

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Muscidae

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Oh! Whoops. What have I missed that points to Muscidae not Anthomyiidae?
I couldn´t make out the anal vein.


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In that case,
the list of known Muscidae here is as follows

Coenosia pumila (Fallén, 1825)

Graphomya maculata (Scopoli, 1763)

Helina annosa (Zetterstedt, 1836)

Hydrotaea armipes (Fallén, 1825)
Hydrotaea cristata Malloch, 1918
Hydrotaea dentipes (Fabricius, 1805)

Limnophora pandellei Séguy, 1923
Limnophora riparia (Fallén, 1824)
Limnophora sinuata Collin, 1930
Limnophora uniseta Stein, 1916

Lispe consanguinea Loew, 1858

Musca domestica Linnaeus, 1758

* Muscina stabulans (Fallén, 1817)

Mydaea palpalis Stein, 1916

Myospila meditabunda (Fabricius, 1781)

* Ophyra aenescens (Wiedemann, 1830)

Phaonia errans (Meigen, 1826)

Spilogona alpica (Zetterstedt, 1845)
Spilogona baltica (Ringdahl, 1918)
Spilogona contractifrons (Zetterstedt, 1838)
Spilogona depressiuscula (Zetterstedt, 1838)
Spilogona megastoma (Boheman, 1866)
Spilogona micans (Ringdahl, 1918)
Spilogona opaca (Schnabl, 1915)
Spilogona pacifica (Meigen, 1826)

Thricops cunctans (Meigen, 1826)
Thricops longipes (Zetterstedt, 1845)
Thricops rostratus (Meade, 1882)

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So maybe one of the Spilogona sp?

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If it is Spilogona, of the species known, comparing against BOLD systems images, S.alpica, S.baltica or S.micans seem closest.

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There are 4 pairs of postsutural dorsocentrals. The very few Anthomyiidae with 4 pairs are very hairy. There is only one dorsal or posterodorsal bristle on the hind tibia. Very few Anthomyiidae have this character.

There appear to be crossed interfrontal bristles, common in Anthomyiidae but mostly restricted to the tribe Azeliini in Muscidae. The small lower calypter is also typical for Anthomyiidae but found in a few Muscidae including members of tribe Azeliini.

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Of the species you listed, I would first check Thricops rostratus which has a projecting chin.

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Oh nice, yes.

The chaetotaxy didn't look quite right for the similar Spilogona
And none had the projecting chin in quite the same way
Which seems distinctive

Of the three Thricops on the list
Thricops cunctans does not have the protruding chin
Thricops longipes has thoracic marking

In Steven Falk´s Flickr account for UK Muscidae he notes the other two Thricops with black legs and protruding chin in UK have a complete row of anteroventrals on hind femora. So this is concurrent with T.rostratus in regard to UK fauna too, with only 3-4 AVs.
https://www.flick...297408293/

At a similar latitude in Norway there are two with distribution visible on ArtsDataBanken not present in UK list so not covered by Falk.
T.lividiventris and T.furcatus.
T.lividiventris doesn´t have the projecting chin.
I am unable to find an image of T.furcatus yet.

But T.rostratus is so common here in Iceland that it even warrants a common name - Trjónufluga
https://www.ni.is...-rostratus

So overall, seems very plausible.
Thanks John

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John, You offered the probability. I have nothing to add.

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Thanks both.

With regard to the possibility of T.furcatus which I couldn't rule out, Ian Andrews on iNaturalist said :

"Yes, that looks to fit to me...the prealar bristle is definitely shorter than the posterior notopleural, which points to rostratus (at least from UK species). furcatus apparently has only 3 post-sutural DCs acc. Gregor et al. 2002 "