January 23, 2024

Explorations in European Sphaerophoria

Toward the end of last year I've tried to deal with the European Sphaerophoria observations. I've added sex and life stage annotations to almost all of them except mating pairs, which I have marked with the observation field 'copulating'. Hopefully now the phenology graphs on the genus taxon page are more meaningful (especially because the 'no annotation' plot on the sex phenology graph basically corresponds to 'mating season').

I've also been rolling out the observation field 'Sphaerophoria identifiable group', which was created by @upupa-epops for North American species, but he kindly added some categories for Europe. The main aim of this really is to try and make it possible to find the things that aren't S scripta! The rules I've followed for each value are:

'cf. S scripta': for males that I suspect of being more elongate but can't properly judge the length: for females with a scripta-like marking on T5 (well separated bars terminating in distinct inward-angled longitudinal wedges).
'interrupta group': for specimens I suspect of being a spotted species, primarily interrupta, fatarum or philantha, especially if there is a strong face stripe (the spots being well formed rather than looking like darkened bands)
'Complete lateral scutum stripes': for specimens that have complete lateral stripes on the scutum but seem to not be scripta or interrupta-group
'"cleoae" pattern': for females exhibiting cleoae characteristics regardless of species (terminal tergites/sternites fused into rings, bands broken in the lateral third).

I have also added the observation field 'cf' to several observations, especially if I suspect interrupta s.s. (broad spots and strong face stripe), or taeniata (very bright; female T5 short with quite straight bars narrowly joined or nearly so by an 'isthmus' in the middle)

Highlights included iNat's first S estebani (quite probably the first live photo of that species!), and the second S loewii

"cleoae" I find quite interesting. Almost all of these I assume to be S scripta, but there is one definate S rueppellii and one probable S taeniata. I don't know how much is known about the "cleoae" phenomenon in Europe.

Posted on January 23, 2024 01:16 PM by matthewvosper matthewvosper | 1 comment | Leave a comment

June 30, 2023

Key to the Greenbottles (Lucilia) of Europe with some notes on Africa

The genus Lucilia is very difficult to identify from photographs (as are many other genera of blow flies). But the greenbottles are also very commonly observed, and there is a tendency to overidentify certain species (I'm looking at you sericata...). Most people I know are surprised to discover that there are eight species of greenbottle known just from the UK. There are a further three species in the rest of Europe. As a result of this perfect storm, Lucilia observations on iNaturalist are, frankly, a bit of a mess.

The presentation below should give an idea of what it is necessary to photograph in order to have the best chance of getting identifiable pictures. To spell it out:
 1) The bristles on the top of the thorax
 2) The base of the wing from the front (not the top)
 3) The bristles on the middle tibia (the best angle is to look toward the front of the side of the thorax from just a position just back of the middle leg.
 4) The space between the eyes (frons).

The key below is primed for use with photographs but, even so, identification will frequently be impossible. Hopefully it will raise awareness and increase people's confidence to tackle the huge and tangled backlog of observations on iNaturalist.

Which brings me to... Africa! As far as I can tell there is only one additional species of Lucilia in Africa: Lucilia infernalis. This species is immediately distinctive because of the extensive and dark infuscation on the leading half of the wing. I do not know much else about it except that it is widespread in the Afrotropical region, but a picture of it can be seen in Figure 5 of this paper. This is more likely to be confused with certain species of Chrysomya - particularly C laxifrons. Chrysomya can be distinguished by the black margins of the tergites, and the wing infuscation is much better defined in those species that have it. I cannot confidently give a list of which European species may also be present in Africa - I know that L cuprina and L. sericata are widespread on the continent, but others may also be present especially in the north. I believe that only those two species are present in Arabia, so there is little risk of Asian species impinging on East Africa.

The Key below covers the European species and also gives information about how to distinguish 'True greenbottles' from lookalikes. Species found in the UK are underlined. The usual caveat applies: I've made this for my own learning and hopefully for the benefit of others, I believe it to be accurate and based on sound sources carefully considered - but I am not an expert, and Calliphoridae are even outside of my normal activities, so bear that in mind.

The species covered are: Lucilia ampullacea, bufonivora, caesar, cuprina, illustris, magnicornis, pilosiventris, regalis, richardsi, sericata and silvarum.

Posted on June 30, 2023 08:44 PM by matthewvosper matthewvosper | 6 comments | Leave a comment

March 27, 2023

Key for the Identification of the Centipedes of the British Isles from Photographs

In addition to the Millipede Key I've also been working on a Centipede Key - so here it is! As with the millipedes, the strategy is to deploy the most obvious features first, and where possible to include a number of different features, and in addition to try and follow the taxonomy step by step from the broader IDs down to species level, enabling the finest possible ID to be given - this is often not possible, but an attempt has been made. These two strategies can sometimes conflict, so compromises have to be made.

To my tremendous surprise I have ended up keying out every British species, although it will not allow the confident identification of every species in every combination of habitat and leg count: the Geophilus flavus/seurati/osquidatum group is particularly knotty (there are also a couple more species of very doubtful presence in the UK that I have ignored such as Schendyla monoeci). There are a few species that key out in two or even three places (L. borealis). I have tried to use features that might just be visible in a high quality macro photograph from above or the side - very rarely have I included a ventral feature. It is worth noting however that in practice most photographs will not be identifiable to species, especially in Cryptops.

I have not illustrated this key - I might add some pics at some time later, but there isn't much available. However there are pictures of the vast majority of British species on the website of the British Myriapod and Isopod Group www.bmig.org.uk/checklist/centipede-checklist which can be used to help interpret the key. The key also draws heavily on information in Tony Barber's AIDGAP guide.

After the key are a couple of charts illustrating the trunk length of Geophilomorph species and the antennal length of Lithobiomorph species.

KEY TO THE ORDERS OF BRITISH CENTIPEDES
1. a. 35-101 leg pairs (even in juveniles).
b. 21 or 15 leg pairs, juveniles may have fewer, it is not uncommon for legs to be snapped off - especially the hind legs which should point backwards.
ORDER GEOPHILOMORPHA
CLASS CHILOPODA cont...
29
2
2. a. 21 leg pairs (even in juveniles)

b. 15 leg pairs, juveniles may have fewer.
ORDER SCOLOPENDROMORPHA (Subgenus Cryptops (Cryptops))
CLASS CHILOPODA cont...
4

3
3. a. Legs exceptionally long and spindly, even more so towards the back (some over half the length of the body), tergites of a similar length, body with three longitudinal dark stripes.
b. Legs not exceptionally long and spindly, always less than half the body length, tergites 1-7 and 8-15 alternating long and short (7+8 are both long), body without three longitudinal dark dorsal stripes..
ORDER SCUTIGEROMORPHA (Scutigera coleoptrata)
ORDER LITHOBIOMORPHA
End

6
KEY TO THE ORDER SCOLOPENDROMORPHA (Subgenus Cryptops (Cryptops))
4. a. Head with complete longitudinal sutures, X-shaped suture on T1, very large (up to nearly 50mm), no groove on the underside of the hind prefemur.
b. Head sutures incomplete or absent, no X-suture on T1, hind prefemur with or without a distinct longitudinal groove, <40mm.
Cryptops anomalans

Subgenus Cryptops (Cryptops) cont..
End

5
5. a. Head with short sutures at front and back, no ventral groove in hind prefemur
b. No head sutures, ventral longitudinal groove in hind prefemur.
Cryptops parisi
Cryptops hortensis
End
End
KEY TO THE ORDER LITHOBIOMORPHA
6. a. Very small - 4-11mm, 0 or 1 ocellus each side (but there may be a darkened patch around the ocelli), 24-29 antennal articles, legs without spines, tergites without posterolateral projections.
b. Mainly larger species, at least 3 ocelli per side and usually many more, legs with spines (very rarely without spines but then hind legs greatly thickened), 20-54 antennal segments, some tergites with or without projections.)
Genus Lamyctes

Genus Lithobius
7

9
7. a. Chestnut colour, one ocellus each side surrounded by a large black patch, 7-10mm, 25-29 antennal articles, unlikely to be found outdoors.
b. Chestnut or pallid colour, one ocellus each side, 4-11mm, 24-25 antennal articles, ocelli not surrounded by a large black patch.
Lamyctes africanus

Subgenus Lamyctes (Lamyctes)
End

8
8. a. Chestnut colour, one ocellus each side, up to about 11mm, 25 antennal articles, likely to be found outdoors.
b. Pallid colour, no ocelli, up to about 5mm only, 24 antennal articles, unlikely to be found outdoors.
Lamyctes coeculus
Lamyctes emarginatus
End
End
9. a. Legs with obvious dark banding, tergites with a distinctive marbled pattern, (tergite projections on T7,9,11 and 13, 35-46 antennal articles).
b. Legs and tergites without such a pattern, (no other species has tergite projections on T7).
Lithobius variegatus

Genus Lithobius cont...
End

10
10. a. Trunk pale, sometimes greyish, with a darker midline, head usually a more yellowish colour against which the dark eye patches stand out, projections on at least T11, 13.
b. Colouration different, or if pale with a dark stripe then no tergite projections
Subgenus Lithobius

Genus Lithobius cont...
11

12
11. a. Trunk pale, usually greyish, 17mm, projections on T9, 11 and 13, 32-42 antennal segments, no accesory spine between VpP15 and DpP15.
b. Trunk usually more chestnut coloured, 12/13mm, projections on T11 and 13 only but not on T9 except somewhat noticeably in northern specimens, 28-34 antennal segments, accesory spine between VpP15 and DpP15.
Lithobius melanops

Lithobius borealis
End

End
12. a. Small species, a little over 10mm, 20 antennal segments, no tergite projections, tarsi and metatarsi fused on legs 1-11.

b. Mostly larger species, >20 antennal segments, tarsi and metatarsi not fused, tergites with projections or not.
Subgenus Lithobius (Monotarsobius)
Genus Lithobius cont...
13

14
13. a. Broad projection on posterolateral apex of the hind tibia of males, 6-9 Ocelli arranged with two large posterior ocelli side by side and an 'incomplete rosette' in front of them (appearance of tapering posteriorly).
b. No such hind leg projection in males, 9-13 with one larger posterior ocellus and the others arranged in about 4 columns of three posteriorly and 2 anteriorly (impression of narrowing anteriorly)).
Lithobius curtipes

Lithobius crassipes
End

End
14. a. Small species with characteristic body shape tapering towards the head, and thickened hind four legs giving the appearance of a Cryptops. 23-27 antennal articles, no tergite projections.
b. Larger species with at least 26 antennal articles, body shape and hind legs different.
Lithobius microps

Subgenus Lithobius (Lithobius)
End

15
15. a. No tergite projection on T9.

b. Tergite projection on T9.
Subgenus Lithobius (Lithobius) cont...
Subgenus Lithobius (Lithobius) cont...
16

22
16. a. No tergite projections on T11 or 13

b. At least with tergite projections on T13.
Subgenus Lithobius (Lithobius) cont...
Subgenus Lithobius (Lithobius) cont...
17

20
17. a. Tiny species (8mm), tergites with wrinkled appearance, chestnut colour, 23-34 antennal articles. (usually does have projections on T11 and 13 but keys out here because they may be indistinct).
b. Dark or pale species, tergites not with wrinkled appearance, larger, about 15mm, 33-50 antennal articles).
Lithobius lapidicola

Subgenus Lithobius (Lithobius) cont...
End

18
18. a. Pale species, may have a darker stripe, rare and Scottish, 33-50 antennal articles, head not distinctly wider than trunk, tergites not 'wrinkled'.
b. Darker species,26-50 antennal articles, may have an enlarged head.
Lithobius lucifugus

Subgenus Lithobius (Lithobius) cont...
End

19
19. a. Dark species, enlarged head, especially in males, much broader than the trunk. Males without a distinct projection on the inside apex of the hind tibia, 39-50 antennal articles, 10-14 ocelli arranged in a forward pointing triangle.
b. Head not enlarged, males with or without a dictinct apical projection on the inside of the hind femur, 6-9 ocelli arranged as a rosette with two larger ocelli positioned side by side posterodorsally to the rosette.
Lithobius muticus

Lithobius calcaratus
End

End
20. a. Very large species (35mm) hind legs nearly half the body lenth, 29-34 antennal articles, evenly coloured.
b. very small species 8-13mm, hind legs in normal proportion to the body, 26-34 antennal articles, often with a darker medial line.
Lithobius pilicornis
Subgenus Lithobius (Lithobius) cont...
End
21
21. a. Tiny species (8mm), tergites with wrinkled appearance, chestnut colour, 23-34 antennal articles, tergite projections may be indistinct, without a hint of a projection on T9, no accesory spine between VpP15 and DpP15.
b. 12/13mm, tergites without 'wrinkled' appearnace, may be a hint of a projection on T9 especially in northern specimens, 28-34 antennal segments, accesory spine between VpP15 and DpP15.
Lithobius lapidicola

Lithobius borealis
End

End
22. a. Larger species (>20mm), prominent projections, 35-54 antennal segments.

b. Smaller species (<20mm), more or less prominent projections, 36-45 antennal segments
Subgenus Lithobius (Lithobius) cont...
Subgenus Lithobius (Lithobius) cont...
23

25
23. a. Found in only one location in Sheerness (Kent), projections on T11 and 13 distinctly narrower than those on T9, 38-52 antennal segments.
b. More widespread or very ubiquitous species, tergite projections not distinctly narrower on T11 and 13, 35-54 antennal segments.
Lithobius peregrinus

Subgenus Lithobius (Lithobius) cont...
End

24
24. a. Rare, southern species, 49-54 antennal segments, 11-16 ocelli.
b. Completely ubiquitous, 35-43 antennal segments, 20-30 ocelli.
Lithobius piceus
Lithobius forficatus
End
End
25. a. Very prominent tergite projections, 39-45 antennal segments.

b. Small and narrow projections, 28-45 antennal segments
Subgenus Lithobius (Lithobius) cont...
Subgenus Lithobius (Lithobius) cont...
26

27
26. a. The projections on T13 significantly larger than those on T9, 32-42 antennal segments, 10-13 ocelli - this species will only key out here if the colour is more uniform than usual.
b. Projections on T9, 11, 13 all very pronounced, 39-45 antennal segments, 7-9 ocelli.
Lithobius melanops

Lithobius macilentus
End

End
27. a. 28-34 antennal segments, accesory spine between VpP15 and DpP15 - this species will only key out here if the colour is more uniform than usual.
b. 36-45 antennal segments, no accesory spine between VpP15 and DpP15
Lithobius borealis.

Subgenus Lithobius (Lithobius) cont...
End

28
28. a. 14-18 ocelli in 4-5 rows, 36-43 antennal articles, T9 projections not noticably broader than the others, head not typically darker than the body.
b. 10-12 ocelli, 40-45 antennal articles, T9 projections broader than the others, head typically darker than the body.
Lithobius tenebrosus

Lithobius tricuspis
End

End
KEY TO THE ORDER GEOPHILOMORPHA
29. a. Body greyish except orange at both ends.
b. Different body colour.
ORDER GEOPHILOMORPHA cont...
ORDER GEOPHILOMORPHA cont...
30
31
30. a. 51-57 leg pairs, often found on vertical surfaces eg walls, tree trunks.
b. >63-75 leg pairs, usually found on the ground.
Geophilus carpophagus
Henia vesuviana
End
End
31. a. Body distinctly reddish throughout (if uncertain key both ways).
b. Body not distinctly reddish throughout.
ORDER GEOPHILOMORPHA cont...
ORDER GEOPHILOMORPHA cont...
32
36
32. a. 37-41 leg pairs, body distinctly tapering toward the head.
b. At least 45 leg pairs, body tapering or not.
Strigamia acuminata
ORDER GEOPHILOMORPHA cont...
End
33
33. a. Body distinctly tapering toward the head, 47-53 leg pairs.
b. Body not tapering toward the head, 45-53 leg pairs.
Genus Strigamia
ORDER GEOPHILOMORPHA cont...
34
35
34. a. Pleurites of the final trunk segment fused to the pretergite, 49-53 leg pairs, widespread.
b. Pleurites of the final trunk segment not fused to the pretergite, 47-51 leg pairs, exclusively littoral including in estuaries.
Strigamia crassipes
Strigamia maritima.
34
35
35. a. Hind legs with claw, in males hind legs only moderately swollen, widespread
b. Hind legs without claw, in males hind legs grossly swollen, exclusively littoral SW.
Geophilus easoni
Hydroschendyla submarina
End
End
36. a. Antennae with elongate articles so that the length of the antennae are five or more times as long as the width of the head, pale yellowish species with distinctly redder heads.
b. Antennae and their constituent articles shorter relative to the head, colour contrast between the body and head less distinct if present.
Genus Geophilus

ORDER GEOPHILOMORPHA cont...
37

39
37. a. 49 leg pairs.
b. 51-57 leg pairs.
c. 59-63 leg pairs.
Geophilus flavus
Genus Geophilus cont...
Geophilus osquidatum
End
38
End
38. a. Exclusively found in littoral habitats, carpophagus fossae on underside, may have 51 leg pairs.
b. May be found anywhere, no carpophagus fossae on underside, may have 51 leg pairs.
c. Known distribution Wales, Western and Southern England, carpophagus fossae on underside, at least 53 leg pairs.
Geophilus seurati
Geophilus flavus
Geophilus osquidatum
End
End
End
39. a. >90 leg pairs (Cornwall).
b. 77-83 leg pairs.
c. 59-75 leg pairs.
d. 51-57 leg pairs.
e. <51 leg pairs.
Haplophilus souletina
ORDER GEOPHILOMORPHA cont...
ORDER GEOPHILOMORPHA cont...
ORDER GEOPHILOMORPHA cont...
ORDER GEOPHILOMORPHA cont...
End
40
41
42
44
40. a. Hind coxae dorsally covered in pores, head shorter than broad, max 83 leg pairs.
b. Hind coxae not dorsally covered in pores, head as long as broad, max 81 leg pairs.
Haplophilus subterraneus
Stenotaenia linearis
End
End
41. a. Forcipular tergite trapezoidal, (narrower anteriorly) and straight sided, some coxal pores opening dorsally at the base of the hind coxae, head slightly longer than broad
b. Forcipular tergite not much narrower at the front and with rounded edges, hind coxae without dorsal pores, head as long as broad).
Geophilus electricus

Stenotaenia linearis
End

End
42. a. Short for its leg count (<20mm) and very pale with hind legs stubby.
b. longer species, yellower with darkened head, hind legs normal.
Henia brevis
Genus Geophilus
End
43
43. a. Not in Shetland, (with an isolated ventral pore in the centre of the hind coxae, forcipule without an accessory claw).
b. Shetland, (but is *G impressus* present there too? Currently no records) (without an isolated ventral pore in the centre of the hind coxae, forcipule with an accessory claw).
Geophilus impressus
Geophilus proximus
End
End
44. a. Hind coxae dorsally covered in pores, head distinctly (>1.25x) longer than broad.
b. Hind coxae not dorsally covered in pores, head barely longer than broad.
ORDER GEOPHILOMORPHA cont...
ORDER GEOPHILOMORPHA cont...
45
48
45. a. Head in dorsal view parallel sided, forcipular tergite also parallel sided, coastal sites, head not distinctly narrower than gap between the poison claws, found outside in the UK.
b. Head distinctly narrower than the gap between the poison claws, broadest at the front; forcipular tergite very narrow, trapezoid, giving the appearance of a neck between the claws, only known from greenhouses.
Pachymerium ferrugineum

Family Mecistocephalidae
End

46
46. a. 49 leg pairs, head twice as long as broad, up to about 40mm only known from the Eden project.
b. <49 leg pairs, head about 1.3x as long as broad, body may be distinctly longer or distinctly shorter
Mecistocephalus guildingi
Family Mecistocephalidae cont...
End
47
47. a. 45 leg pairs, short species up to 20mm, known from various greenhouses in southern England.
b. 43 leg pairs, long species up to 60mm, old records from greenhouses in Northern England and Scotland.
Tygarrup javanicus
Dicellophilus carniolensis
End
End
48. a. 35-37 leg pairs, stocky orange yellow species, forcipular tergite very short.
b. At least 37 leg pairs, normally proportioned and paler species, sometimes with head slightly redder, forcipular tergite normal.
Eurygeophilus pinguis
ORDER GEOPHILOMORPHA cont...
End
49
49. a. Exactly 45 leg pairs, pallid species, very slender hind legs ending in a bristled tubercle. Scilly, Cornwall coasts.
b. Hind legs different.
Arenophilus peregrinus
ORDER GEOPHILOMORPHA cont...
End
50
50. a. 37-39 segments, pale species, head resembling Pachymerium, hind leg normal (metatarsus not reduced) with claw, Scilly and Isle of Wight.
b. If 39 segments then either hind leg with reduced metatarsus or typical Geophilus appearance (yellowish with darker head).
Nothogeophilus turki

ORDER GEOPHILOMORPHA cont...
End

51
51. a. Hind legs with the final segment much shorter and without claw, pale species.
b. Hind legs normal with claw.
Genus Schendyla
Genus Geophilus
52
54
52. a. Hind legs relatively long (>1.5x the previous pair ignoring coxae), the final segment of the hind legs 1/3-1/2 as long as the penultimate, not shorter, 37-43 leg pairs.
b. Hind legs <1.5x as long as the previous pair ignoring coxae, the final segment <1/3 as long as the penultimate, 39-49 leg pairs.
Schendyla nemorum

Genus Schendyla cont...
End

53
53. a. The final segment of the last leg 1/5-1/3 the length of the penultimate, 39-49 leg pairs, exclusively coastal and southern.
b. The final segment of the last leg minute - <1/7 the length of the penultimate, 39 leg pairs exactly, widespread.
Schendyla Peyerimhoffi
Schendyla dentata
End
End
54. a. At least 45 leg pairs.
b. Fewer than 45 leg pairs.
Genus Geophilus cont...
Genus Geophilus cont...
43
55
55. a. Head 1.3x as long as broad and rather rectangular, coastal sites, southern, males 41 leg pairs, females 43 leg pairs.
b. Head about as long as broad, widespread, males 37-39 leg pairs, females 39-41
Geophilus pusillifrater
Geophilus truncorum
End
End

British Geophilomorpha by Number of Leg Pairs

Colours represent families: Green = Geophilidae, Red = Lintotaeniidae, Pale yellow = Schendylidae, Purple = Mecistocephalidae, Grey = Dignathodontidae, Golden brown = Himantariidae,

British Lithobiomorpha by Number of Antennal Articles:

Colours in header row represent subgenera: Cyan = Lithobius (Monotarsobius), Purple = Lithobius (Sigibius) [Myriatrix] or Lithobius (Polybothrus) [Chilobase], Yellow = Lamyctes (Lamyctes), Green = Lamyctes (Metalamyctes), Red = Lithobius (Lithobius)

Colours in the body represent tergite projections: Red (Lithobius) and Black (Lamyctes) = No tergite projections, Yellow = T7, 9, 11 and 13, Green = T9, 11 and 13, Blue = T11 and 13 but pale blue are those variable or ambiguous species that usually have T11 and 13 only but may also have T9 (borealis) or may lack projections of T11 and even occasionally T13 (lapidicola)


Posted on March 27, 2023 03:30 PM by matthewvosper matthewvosper | 2 comments | Leave a comment

March 21, 2023

Key for the Identification of the Millipedes of the British Isles from Photographs

So here's something I've been working at on-and-off for a while as a bit of a learning exercise. This is my best attempt at a key to the Millipedes of the British Isles from Photographs on iNat. The strategy is in line with other keys I have done for hoverflies: photographs don't give you the opportunity to choose which features you look at, and are often short on detail, so the key tries to deploy the most obvious features first, and where possible to include a number of different features. In addition, for iNat purposes it is helpful to try and follow the taxonomy step by step from the broader IDs down to species level, enabling the finest possible ID to be given - this is often not possible, but an attempt has been made. These two strategies can sometimes conflict, so compromises have to be made.

Of course certain species simply cannot be identified without microscopic treatment and therefore the key sometimes ends at a higher level (where it is not obvious I have listed the possible taxa in a footnote marked e.g. '(1)'). I have tried to use features that might just be visible in a high quality macro photograph.

I have not illustrated this key - I might add some pics at some time later, but there isn't much available. However there are pictures of the vast majority of British species on the website of the British Myriapod and Isopod Group www.bmig.org.uk/checklist/millipede-checklist which can be used to help interpret the key.

KEY TO THE ORDERS OF BRITISH MILLIPEDES
1. a. Body covered in obvious tufts of thick feathery setae and tufts of especially long setae extending backwards from the rear; 11 segments; less than 4mm long.
b. Body not covered in such tufts; usually longer.
ORDER POLYXENIDA (Polyxenus lagurus)
SUBCLASS CHILOGNATHA
End

2
2. a. 12 segments (can look like 11); woodlouse-like appearance; can curl into a ball (not a spiral).

b. More than 18 segments.
ORDER GLOMERIDA (Family Glomeridae)
SUBCLASS CHILOGNATHA cont...
8

3
3. a. 19 or 20 segments; often with 'flat-backed' appearance.
b. More than 25 segments.
ORDER POLYDESMIDA
SUBCLASS CHILOGNATHA cont...
12
4
4. a. 26 to 32 segments; head distinctly wider than the segments immediately behind it; may have 'flat-backed' or cylindrical appearance.
b. More than 32 segments; head a similar width to th following segments.
ORDER CHORDEUMATIDA

SUBCLASS CHILOGNATHA cont...
22

5
5. a. Head conical or 'beak-like'.

b. Head rounded.
SUPERORDER COLOBOGNATHA
SUPERORDER JULIFORMA
6

7
6. a. Ocelli present; found outdoors in the British Isles.
b. Ocelli absent; never found outdoors in the British Isles.
ORDER POLYZONIIDA
ORDER SIPHONOPHORIDA
11
End
7. a. Medial suture on the face to the labrum; not found outdoors in the British Isles.
b. Medial suture not extending to the labrum; found outdoors in the British Isles.
ORDER SPIROBOLIDA
ORDER JULIDA
End
34
KEY TO THE ORDER GLOMERIDA (Family Glomeridae)
8. a. Tergites rough and tuberculate; tergites pale or dark.
b. Tergites smooth and pale.
Family Glomeridae cont...
Subfamily Doderiinae
9
10
9. a. Tergites dark with pale borders.
b. Tergites entirely pale.
Glomeris marginata
Geoglomeris subterranea
End
End
10. a. Hind margins of tergites raised into distinct ridges.
b. Tergite hind margins not raised.
Trachysphaera lobata
Adenomeris gibbosa
End
End
KEY TO THE ORDER POLYZONIIDA
11. a. Small thread-like pink/purple millipede not found outside in UK.
b. Broad bodied brown millipede found outside in UK.
Rhinotus purpureus
Polyzonium germanicum
End
End
KEY TO THE ORDER POLYDESMIDA
12. a. Paranota with contrastingly pale colour compared to the main trunk.
b. Paranota of similar colouration to the trunk.
ORDER POLYDESMIDA cont...
SUBORDER POLYDESMIDEA
13
15
13. a. Dark brown millipede, paranota with white-ish tips, white-pointed telson and dark legs.
b. Reddish brown millipede with more orangish paranota.
Chondrodesmus cf riparius
Family Paradoxosomatidae
End
14
14. a. Pale colour restricted narrowly to the edges of the paranota, not found outdoors in the UK.
b. Pale colour in larger squarish patches at the sides of the paranota.
Oxidus gracilis
Stosatea italica
End
End
15. a. Was found outdoors in the British Isles (This is a shortcut - species compatible with the British Isles' climate will key out both ways).
b. Was not found outdoors in the British Isles.
INFRAORDER POLYDESMOIDES

SUBORDER POLYDESMIDEA cont...
16

19
16. a. Tiny translucent/white millipede whose rounded paranota create a 'string-of-beads' appearance.
b. Larger and more robust species whose paranota jut out as flattish ledges.
Family Macrosternodesmidae
Family Polydesmidae
End
17
17. a. 19 segments, small species.
b. 20 segments.
Brachydesmus superus
Family Polydesmidae cont...
End
18
18. a. Pinkish brown millipede with particularly well-rounded paranotal edges in dorsal view in the middle portion, typically found along the M4 corridor.
b. Different.
Propolydesmus testaceus

Genus Polydesmus
End

End
20. a. Paranota extended to the side as 'ledges'.
b. Paranota expanded 'rubber-ring-style'.
Family Polydesmidae
SUBORDER POLYDESMIDEA cont...
17
21
21. a. Tiny translucent/white millipede with 'string-of-beads' appearance found outdoors in UK.
b. Different.
Family Macrosternodesmidae
SUBORDER POLYDESMIDEA (1)
End
End
KEY TO THE ORDER CHORDEUMATIDA
22. a. Paranota laterally prominent in dorsal view.

b. Paranota not laterally prominent in dorsal view, (the segments smoothly cylindrical).
SUBORDER CRASPEDOSOMATIDEA
Family Chordeumatidae
26

23
23. a.Pallid species with ocelli in a flattened triangle, 28 or 30 segments
b. Darker species with ocelli in equilateral triangle, 30 segments.
Genus Melagona
Family Chordeumatidae cont...
24
25
24. a. 28 segments.
b. 30 segments.
Melagona scutellaris
Genus Melagona
End
End
25. a. In side view, male gonopods with large white structures filling the gap between anterior and posterior paragonopods (This area is not obscured by legs).
b. In side view, male gonopods with the gap between anterior and posterior paragonopods visible. (This area is not obscured by legs).
Genus Chordeuma

Orthochordeumella pallida
End

End
26. a. Large orange-brown millipede with paranota extremely well developed, having the appearance of a Polydesmus
b. Paranota less well developed, or colour different.
Nanogona polydesmoides
SUBORDER CRASPEDOSOMATIDEA cont...
End
27
27. a. Sides of the body and the dorsal midline dark - not reaching to the paranota - sides of the dorsum pale.
b. Different.
Ceratosphys amoena confusa
SUBORDER CRASPEDOSOMATIDEA cont...
End
28
28. a. Body unpigmented - very pure white.

b. Colour at least dirty white.
SUBORDER CRASPEDOSOMATIDEA cont...
SUBORDER CRASPEDOSOMATIDEA cont...
29

32
29. a. Body bearing long and stout curved setae.

b. Setae normal.
SUPERFAMILY ANTHROLEUCOSOMATOIDEA
Genus Brachychaeteuma
30

31
30. a. Paranota and cheeks very well developed.
b. Paranota and cheeks not very well developed.
Psichrosoma cf breuili
Cranogona dalensi
End
End
31. a. About 3 poorly pigmented ocelli
b. About 6 well pigmented ocelli
Genus Brachychaeteuma
Brachychaeteuma melanops
End
End
32. a. Body bearing many very long stout setae.
b. Setae much less prominent.
Hylebainosoma nontronensis
SUBORDER CRASPEDOSOMATIDEA cont...
End
33
33. a. Dark brown millipede, paler over the paranotal bumps.
b. Dark brown millipedes without such a pattern.
Craspedosoma rawlinsii
SUBORDER CRASPEDOSOMATIDEA (2)
End
End
KEY TO THE ORDER JULIDA
34. a. Small thread-like millipedes without longitudinal striae on the metazonites; never very dark, sometimes pure white with brightly coloured (red/orange) ozadenes.
b. More robust-shaped millipedes, sometimes large; longitudinal striae on the metazonites; sometimes very dark, always at least dirty white (never pure white); if visible, ozadenes usually dark red/brown, rarely brightly coloured.
ORDER JULIDA cont...

Family Julidae
35

39
35. a. Pure white millipede with brightly coloured (red/orange) ozadenes and without ocelli.
b. At least slightly pigmented and with less bright ozadenes; ocelli present.
Subfamily Blaniulinae
ORDER JULIDA cont...
36
37
36. a. Ozadenes red.
b. Ozadenes orange.
Blaniulus guttulatus
Tribe Boreoiulini (3)
End
End
37. a. Ocelli arranged in a roughly equilateral triangular patch.
b. Ocelli arranged in a narrow horizontal bar.
Family Nemasomatidae
Family Blaniulidae
End
38
38. a. Ocelli arranged in a single row.
b. A couple of ocelli placed higher than the main row so that the ocellar bar appears to widen anteriorly.
Family Blaniulidae (4)
Proteroiulus fuscus
End
End
39. a. Robust dark millipede with pink legs and antennae.
b. Legs and antennae not pink.
Ommatoiulus moreleti
Family Julidae cont...
End
40
40. a. Body with stripes running most of its length (Be aware that immatures of some unstriped species may exhibit vague stripes).
b. Different.
Family Julidae cont...

Family Julidae cont...
41

44
41. a. Dark with narrow pale medial stripe
b. Dark with pale submedial stripes and dark medial stripe.
Leptoiulus belgicus
Family Julidae cont...
End
42
42. a. Robust brown millipede with pale stripes orangeish, and dorsal projection of telson.
b. Smaller millipede, pale stripes not orange.
Ommatoiulus sabulosus
Genus Brachyiulus
End
43
43. a. Found near the Eden project!
b. Found far from the Eden project.
Genus Brachyiulus
Brachyiulus pusillus
End
End
44. a. Pale body with relatively brightly coloured ozadenes, no ocelli. (Beware of Cylindroiulus salicivorus in Edinburgh which is pale with orange ozadenes and just a few poorly pigmented ocelli)
b. Usually more pigmented; ocelli present, ozadenes usually dull or dark coloured if visible.
Family Julidae cont...

Family Julidae cont...
45

46
45. a. Ozadenes orange, telson with dorsal projection.
b. Ozadenes red, telson lacking dorsal projection.
Cylindroiulus vulnerarius
Metaiulus pratensis
End
End
46. a. Telson without dorsal projection.
b. Telson with dorsal projection.
Family Julidae cont...
Family Julidae cont...
47
49
47. a. Hind segment with ploughshare-like forward-pointing ventral projection; not a very dark species.
b. Hind segment with no such projection; dark or pale.
Unciger foetidus
Genus Cylindroiulus
End
48
48. a. Large (>20mm) dark blue-bronze millipede.
b. Small (<20mm) Brown to pale millipede.
Cylindroiulus caeruleocinctus
Genus Cylindroiulus (5)
End
End
49. a. Telson projection club-shaped.
b. Telson projection not club-shaped.
Genus Cylindroiulus
Family Julidae cont...
50
51
50. a. Very large (>>30mm) and very dark millipede.
b. Much smaller (<<30mm) pale pinkish brown millipede.
Cylindroiulus londiniensis
Cylindroiulus puctatus
End
End
51. a. Large very dark millipede with transverse striae on prozonates, and strongly contrasting white legs.
b. Large or small, dark or pale millipede without transverse striae on prozonates
Tachypodoiulus niger
Family Julidae cont...
End
52
52. a. Hind segment with ventral projection.
b. Hind segment without ventral projection.
Family Julidae cont...
Family Julidae cont...
53
55
53. a. Hairs on body arranged in conspicuous fringes on the metazonites and not limited to hind segments.
b. Hairs on body less conspicuous and limited to hind segments.
Enantiulus armatus
Genus Cylindroiulus
End
54
54. a. Large millipede >30mm.
b. Smaller species.
Cylindroiulus apenninorum
Cylindroiulus pyrenaicus
End
End
55. a. Pallid species with orange ozadenes and few, weakly pigmented ocelli.
b. Usually very dark species, if pallid then with a larger patch of well pigmented ocelli.
Cylindroiulus salicivorus
Family Julidae cont...
End
56
56. a. First leg-pair of males broad at base and then distinctly sickle shaped.
b. Females, or males with different first leg pairs.
Genus Ophyiulus
Family Julidae cont...
End
57
57. a. First leg-pair of males tiny, second with flattened projection
b. Females, or males with different first leg pairs.
Julus scandinavius
Family Julidae cont...
End
58
58. a. First leg pair of males swollen, terminally curved as hooks, 2nd legs with basal sheath-like projections.
b. Females, or males with different first leg pairs.
Leptoiulus kervellei
Family Julidae (6)
End
End

(1) Family Haplodesmidae or Poratia digitata
(2) Genera Anthogona, Anamastigona or Turdulisoma
(3) Genera Boreoiulus or Archiboreoiulus
(4) Genera Choneiulus or Nopoiulus
(5) Cylindroiulus britannicus, latestriatus or parisiorum
(6) Genera Haplopodoiulus or Allajulus, or Cylindroiulus dahli or sagittarius

Posted on March 21, 2023 10:10 AM by matthewvosper matthewvosper | 2 comments | Leave a comment

January 19, 2023

Key to the Bacchini and Melanostomini of the Philippines, Wallacea, Australasia and Oceania

For me the origins of this little escapade can be traced back to the time I was involved with implementing the taxonomy of Platycheirus on iNat a while ago and discovered the intriguing New Zealand subgenus-raised-to-genus Eocheilosia. I learned a little more about the genus some time later through a series of conversations with @steve_kerr to whom I am grateful for showing me descriptions of the species I hadn't yet found. I realised that there weren't too many other Bacchines or Melanostomines in the wider region and thought it could be expanded a bit. So here we are.

I have produced a separate key for the Eocheilosia not only because it is by far the largest genus in the region, but also because the difficulties of that genus are so particularly acute. Be sure to read the introductory slides. I should say that that particular key must be taken with a whole mouthful of salt!! I think of it more as a way of beginning to feel around the genus - any ID should be checked with the original descriptions which are almost all linked to in the Powerpoint (bearing in mind that in Eocheilosia there are as many known undescribed species as there are described species!!)

Species included:

BACCHINI
Baccha maculata
Eocheilosia antipoda, captalis, clarkei, cunninghami, fulvipes, harrisi, howesii, huttoni, leptospermi, lignudus, myersii, notata, ronana
Platycheirus albimanus, stegnus

MELANOSTOMINI
Melanostoma apicale, atrum, fasciatum, fumivenosum, polynesiotes, univittatum
Xanthandrus agrolas, bergmani, bicinctus, orientalis

Posted on January 19, 2023 10:25 PM by matthewvosper matthewvosper | 4 comments | Leave a comment

December 26, 2022

Key to the Milesiini of Australia and New Zealand

Happy Christmas to our Antipodean friends!

I've been trying this out over the last few days and it seems to work for me. Suggestions for improvement are welcome.

There are not a huge number of these flies and they seem to mostly be large, distinctlive and charismatic.

I'd like to extend this further to the wider region but there's a just a couple of descriptions I can't get hold of - hopefully I'll do that at some point.

The 18 species covered are as follows:

Subtribe CRIORHININA
Malometasternum rufocaudatum
Deineches fulva, D hackeri, D nudiventris

Subtribe TEMNOSTOMINA
Odyneromyia illucens, O iridescens, O spadix, O transparens

Subtribe TROPIDIINA
Orthoprosopa (Orthoprosopa) grisea
Orthoprosopa (Paratropidia) bilineata, O (P) multicolor
Syritta hackeri, S luteinervis, S orientalis

Subtribe XYLOTINA
Chalcosyrphus (Hardyimyia) elongata
Chalcosyrphus (Neploneura) pleuralis, C (N) victoriensis
Xylota flavitarsis

Posted on December 26, 2022 03:51 PM by matthewvosper matthewvosper | 6 comments | Leave a comment

October 24, 2022

Key to British Female Platycheirus Incorporating the Main Infrageneric Groupings in iNat

It is best to interpret these keys with sight of quality pictures such as the excellent resource by Steve Falk

In constructing this I have used information from the helpful Book 'Britain's Hoverflies' by Ball and Morris, the key in 'Hoverflies of Northwest Europe' by M.P. van Veen and Steve Falk above.

Some of these species are genuinely impossible to ID from a photo, but I hope that this key might enable more of them to reach a finer level of ID. The female of P. aurolateralis is unknown

For an overview of how the taxonomic groupings used by the UK Hoverfly Recording Scheme relate to the taxa available on iNat see here. For the key to males see here.

Note that the distinctive rosarum and granditarsus have departed for Genus Pyrophaena.

This key is intended to be as useful as possible when IDing from photos, but this will frequently be impossible. Used with a little circumspection I hope it is at least helpful. Be especially aware that it is often difficult in photographs to tell the difference between grey and pale yellow spots. I am very happy to be informed of any errors.

Females:

1. a. Abdomen with broad, but often obscure, grey bands on T3-4 and similarly broad grey spots on T2; the frons is mostly black - a narrow line of dusting extends up the eye margin and ends in small inward pointing triangles above the lunule which may or may not be connected by a narrow line of dusting across the top of the lunule.
b. Abdomen spotted
Subgenus Pachysphyria




Subgenus Platycheirus
P. ambiguus




2
2. a. All femora mostly black; either orange spotted species with face produced forward into a snout or grey spotted species with frons undusted; normally with markings on T5.
b. Face not produced forward into a snout; extensive yellow parts on at least some femora; if grey spotted then femora 1 and 2 almost entirely yellow; with or without markings on T5.
Section manicatus


Subgenus Platycheirus cont…
6


3
3. a. Grey spots; femora 1 and 2 almost entirely yellow (but beware they may darken somewhat in the middle); the frons black with at most small dust markings laterally.
b. Orange spots; femora 1 and 2 with or without black parts; frons more significantly dusted.
Section albimanus (no complex)


Subgenus Platycheirus cont…
10


4
4. a. Small rectangular spots on T3-4, wider than long, smallest on T2. No spots on T5 (or occasionally very obscure); antennal flagellum partly yellowish (can be hard to see from above).
b. Larger, less elongate spots. Clear spots on T5 (Except in P. angustatus which usually also lacks spots on T4 (and P. amplus?) and perhaps melanic specimens but then other spots not as described above).
Section albimanus, Complex scutatus


Subgenus Platycheirus cont…
End


5
5. a. Antennal flagellum completely black; Spots on T2 roundish, positioned closer to the hind edge of the tergite and smaller than on T3-4
b. Antennal flagellum partly yellowish (can be hard to see from above); Spots on T2 usually larger than on other tergites, positioned closer to the front of the tergite and with hind margin distinctly angled backwards toward the midline - otherwise T2 spots greatly reduced, nearer to the hind edge and kidney shaped, (P. amplus) [If the spots on T2 are the largest but the hind margin is flat reconsider whether it could be Section manicatus]
Section albimanus, Complex clypeatus

Section peltatus
11

9
SECTION MANICATUS
6. a. Greyish Spots; face not produced forward into a blunt snout; frons undusted and particularly wide.
b. Orange-yellow spots, face produced forward into a blunt snout.


Section manicatus cont…
P discimanus

7
7. a. Face and frons shining black, only slightly dusted on the eye margin; mouth edge not quite projecting beyond the tubercle; scutum shining black.
b. Face and frons significantly grey dusted; mouth edge protruding past the tubercle or not.


Section manicatus cont…
P melanopsis

8
8. a. Mouth edge projecting beyond the tubercle; scutum grey dusted; frons wholly dusted, even around the vertex.
b. Scutum shining black; mouth edge not quite protruding past the tubercle; frons extensively dusted, but not on the vertex, and not so much medially.


P manicatus

P. tarsalis
SECTION PELTATUS
9. a. Spots on T2 larger than on T3-4, with hind margin sloping distinctly backwards toward the midline, reaching close to the anterior margin of the tergite.
b. Spots on T2 smaller than on T3, at least greatly reduced, kidney shaped, and far from the anterior margin of the tergite.
Section peltatus



End


P. amplus
SECTION ALBIMANUS (No complex)
10. a. Frons with narrow, but normally very clear, dusting on the eye margin ending in a small spot; S2 with long hairs; posterior anepisternum wholly dusted.
b. Frons undusted or only indistinctly on the eye margin; S2 with only short hairs; lower part of posterior anepisternum shining.
P. albimanus

P. sticticus
COMPLEX CLYPEATUS
11 a. Hind femur completely yellow; T6 with yellow markings.
b. Hind femur with at least a black ring; T6 with or without yellow markings.
Complex clypeatus cont...
Complex clypeatus cont...
12
13
12 a. Frons shining black between and below the lateral dust spots
b. Frons vaguely dusted between and below the lateral dust spots.

P. fulviventris
P. perpallidus
13 a. Hind leg wholly black except at the knee. T6 black.
b. Hind leg with more yellow (at least also the apex of the tibia); T6 with or without yellow markings.

Complex clypeatus cont...
P. podagratus
14
14 a. T6 with yellow markings.
b. T6 without yellow markings.
Complex clypeatus cont...
Complex clypeatus cont...
15
16
15 a. T2 spots large; forefemur without a subbasal white bristle; posterior anepisternum shining on the lower half, dusted on the upper half.
b. T2 spots distinctly smaller; forefemur with a subbasal white bristle; posterior anepisternum wholly dusted.

P. scambus

P. immarginatus
16 a. Sides of thorax strongly shining; without spots on T5 and usually also T4.
b. Sides of thorax more dusted; T4-5 with spots.

Complex clypeatus cont...
P. angustatus
17
17 a. Frons with small widely separated lateral spots, the frons black between.
b. Frons with larger dust spots, often with some more obscure dusting between.

Complex clypeatus cont...
P. europaeus
18
18 a. Spots on T3+4 narrowly separated from the front margins of the tergites and not larger than half the length of the tergites.
b. Spots on T3+4 meeting the front margins of the tergites and distinctly larger than half the length of the tergites.


Complex clypeatus cont...
P. occultus

19
19 a. Posterior hair fringe on forefemur confined to the basal half.
b. Posterior hair fringe on forefemur extending to the apex.

P. ramsarensis
P. clypeatus
Posted on October 24, 2022 08:50 PM by matthewvosper matthewvosper | 0 comments | Leave a comment

October 20, 2022

Key to British Male Platycheirus Incorporating the Main Infrageneric Groupings in iNat

It is best to interpret these keys with sight of quality pictures such as the excellent resource by Steve Falk

In constructing this I have used information from the helpful Book 'Britain's Hoverflies' by Ball and Morris, the key in 'Hoverflies of Northwest Europe' by M.P. van Veen and Steve Falk above.

Some of these species are next to impossible to ID from a photo, but I hope that this key might enable more of them to reach a finer level of ID.

For an overview of how the taxonomic groupings used by the UK Hoverfly Recording Scheme relate to the taxa available on iNat see here

Note that the distinctive rosarum and granditarsus have departed for Genus Pyrophaena.

This key is intended to be as useful as possible when IDing from photos, but this will frequently be impossible. Used with a little circumspection I hope it is at least helpful. I am very happy to be informed of any errors.

Males:

1. a. Abdomen with paired grey maculae; face and frons entirely grey dusted; frons is quite large when viewed from above; Foreleg unmodified in shape; femur with apical curled bristle.
b. At least some foreleg segments modified in shape; no curled bristle at the apex of the fore femur; if grey spotted then with at least some shining black undusted parts on frons.
Subgenus Pachysphyria

Subgenus Platycheirus
P. ambiguus

2
2. a. Foretibia not broadened towards the apex; at least foretarsi 1+2 enlarged to produce a smooth curved shape; if abdominal spots are orange then face produced beneath the tubercle into a blunt snout.
b. Foretibia broadened toward the apex; forebasitarsus enlarged in a smooth rounded shape or with pointed corners; face flattish beneath the tubercle.
Section manicatus


Subgenus Platycheirus cont…
4


3
3. a. Orange spots. Foretibia sharply broadened only at the apex; forebasitarsi greatly enlarged, significantly overhanging the tarsi on the inside and with an acute corner on the inside apex; posterior surface of forefemur covered with strong flattened black hairs; middle femur with deep anterior concavity; fore and middle femora never all yellow.
b. Orange or grey spots; Male foretibia broadening throughout most of its length; forbasitarsi expanded into a smooth curved shape; forefemur without flattened black hairs; middle femur without concavity; fore and middle femora may be yellow or not.
Section peltatus



Section albimanus
7



9
SECTION MANICATUS
4. a. Greyish Spots, face not produced forward into a blunt snout.
b. Orange-yellow spots, face produced forward into a blunt snout.

Section manicatus cont…
P discimanus
5
5. a. Face and frons shining black, mouth edge not quite projecting beyond the tubercle; foretarsi 1-3 expanded, pale and tapering towards 4-5 (black); scutum shining black.
b. Face and frons grey dusted; if scutum shining black then only foretarsi 1+2 expanded; mouth edge protruding past the tubercle or not.


Section manicatus cont…
P melanopsis

6
6. a. Mouth edge projecting a little beyond the tubercle; foretarsi 1-3 expanded, pale and tapering towards 4-5 (black); scutum grey dusted; broader bodied; abdominal spots reaching close to the hind margin of the tergites.
b. Scutum shining black; foretarsi 1+2 expanded; mouth edge not quite protruding past the tubercle; narrower bodied; spots not reaching close to the hind margins of the tergites.



P manicatus


P. tarsalis
SECTION PELTATUS
7. a. Larger species; spots on T2 well formed (but not large); middle tibia with moderate ventral swellings at 1/3 length and apex, the former with an indistinct tuft of moderate length black hairs.
b. Smaller species; spots on T2 poorly formed or absent; middle tibia with ventral swellings absent or strong and a distinct flag of long black hairs at 1/3-1/2 length.



Section peltatus cont…
P peltatus


8
8. a. Middle tibia with hardly any ventral swellings at 1/3 length or apex, but with an anterior hair tuft.
b. Middle tibia with pronounced ventral swellings at mid length and apex but no anterior hair tuft; a tuft of hairs arising from the apical swelling pointing upwards parallel to the tibia.
P amplus

P nielseni
SECTION ALBIMANUS
9. a. Normally greyish spots; spots never nearly filling the length of the tergites; if poorly formed and even absent on T2 then the foretibia widening gradually throughout its length, and not greatly expanded; forefemur with only one long posterior black bristle in the apical half (much longer than the surrounding bristles).
b. Normally orange-yellow spots; spots usually well formed, in many species more than 1/2 the length of the tergites; if spots very poorly formed and even absent on T2 then the forefemur expanded suddenly more towards the apex than the rest of the length and with a distinct tuft of black hairs prior to the apical expansion; forefemur may have more long black posterior bristles or not.
Section albimanus cont…



Section albimanus cont…
10



11
10. a. Spots normally fairly well formed except sometimes on T2 with hind margin sloping forwards medially; foretibia greatly broadened; Forefemur without a long wirey posterior bristle at the apex, but with two basal L-shaped tufts of tangled bristles.
b. Spots poorly formed, even missing on T2; foretibia only slightly broadened; Forefemur with a long wirey posterior bristle at the apex, but without basal L-shaped tufts.
P albimanus


P sticticus
11 a. Large orange spots (>1/2 length of tergites 3+4). Without two hooked tufts of bristles at the base of forefemur; metacoxae normal.
b. Small squarish orange spots; Two hooked tufts of bristles at the base of forefemur; metacoxae with finger-like process.
Complex clypeatus

Complex scutatus
13

12
COMPLEX SCUTATUS
12. a. Face and frons wholly silver dusted; spots on T2 well formed.
b. Frons dark or obscurely golden dusted; very obscure abdominal spots especially on T2 where they are usually missing entierly; middle tibia particularly hairy.
c. Frons black; abdominal markings well formed.
P. scutatus
P. aurolateralis

P. splendidus
COMPLEX CLYPEATUS
13 a. T2 with large spots (>1/2 length of tergite).
b. T2 with small spots (<1/2 length of tergite).
Complex clypeatus cont...
Complex clypeatus cont...
14
18
14 a. Hind leg black except narrowly yellow at the knee. T5 black. Foretibia exanded suddenly in the apical 1/3, rounded, curving in again toward the apex.
b. Hind femur, tibia and usually tarsi with some yellow. T5 with yellow markings. Foretibia expanded differently and not curving back in again.


Complex clypeatus cont...
P. podagratus

15
15 a. Hind femur and tibia yellow. Foretibia expanded suddenly in about the apical half, remaining parallel sided to the apex.
b. Hind femur and tibia with some black. Foretibia expanding more gradually from the base to the apex.


Complex clypeatus cont...
P. fulviventris

16
16 a. Forefemur without a basal tuft of long white hairs, but with a posterior row of long strong black bristles. Foretibia, although it expands from the base it contracts again at about 2/3 length before expanding again to the end; black hind border of tergites not much narrower than the width of the black midline.
b. Forefemur with a basal tuft of long white hairs, with or without a posterior row of long strong black bristles; Foretibia expanding continuously from base to apex; black hind border of tergites very narrow or absent - much narrower than the width of the black midline.




Complex clypeatus cont...
P. scambus



17
17 a. Forefemur with a posterior row of long black strong bristles.
b. Forefemur without a posterior row of long black strong bristles, instead with dense, mainly yellow, hair. Apex of middle femur with anteroventral black hairs bent backwards.

P. immarginatus
P. perpallidus
18 a. Notably slender species; pleura distinctly shining, undusted; Forefemur with long black hairs in the basal half sharply bent at their tips. Underside of forebasitarsus with a v-shaped incision. In direct comparison with P. europaeus, the spots on T3 longer.
b. Broader species, though *P. europaeus* is also quite slender; pleura at least partly dusted. Forefemur without such hairs. Underside of forebasitarsus with or without a v-shaped incision.



Complex clypeatus cont...
P. angustatus


19
19 a. Underside of forebasitarsus with a v-shaped incision. Fairly slender species. In direct comparison with P. angustatus, the spots on T3 shorter.
b. Broader species; Underside of forebasitarsus without a v-shaped incision.


Complex clypeatus cont...
P. europaeus

20
20 a. Underside of forebasitarsus with a short narrow pale bare area stretching from the base to a darkened pit in the basal half.
b. Underside of forebasitarsus with a longer narrow pale bare area stretching from the base to a darkened pit in the apical half. Distinctly broader species.


Complex clypeatus cont...
P. occultus

21
21 a. Forefemur with a posterior hair fringe reaching the apex.
b. Forefemur with a posterior hair fringe confined to the basal half.
P. clypeatus
P. ramsarensis
Posted on October 20, 2022 08:17 PM by matthewvosper matthewvosper | 0 comments | Leave a comment

October 17, 2022

Mapping UK Platycheirus recording groups onto iNat taxonomy

The Genus Platycheirus is a very large, nearly cosmopolitan genus of small elongate hoverflies typified by males with distinctive modifications to the shape and/or bristles of parts of the front leg. The fact that it is such a large genus means that it has been subdivided. Traditionally the subdivisions have been based on the morphology of these male forelegs.

In the UK, for the purposes of the National Hoverfly Recording Scheme, the genus has been split up into 'groups'. This is not a taxonomic statement, but one of convenience for recording by grouping similar looking species together. Of course it is often the case that 'looking similar' does have taxonomic significance, and most of the UK groups do indeed align with more widely used taxonomic units. The exception, as we shall see, is the albimanus-group.

The UK groups are:
albimanus-group: inc. albimanus, ambiguus, discimanus, sticticus
manicatus-group: inc. manicatus, tarsalis, melanopsis
peltatus-group: inc. peltatus, nielseni, amplus
scutatus-group: inc. scutatus, aurolateralis, splendidus
clypeatus-group: inc. clypeatus, angustatus, europaeus, fulviventris, immarginatus, occultus, perpallidus, podagratus, ramsarensis, scambus
(Note that Subgenus Pyrophaena i.e P. granditarsus + rosarum is considered a full genus in iNat, not part of Platycheirus at all)

Apart from the UK albimanus-group, all of the above mentioned groups have equivalents in iNat such that if you have a species identified as one of those UK groups it is fine to ID them as 'Section P peltatus', 'Section P manicatus', 'Complex P. clypeatus', or 'Complex P. scutatus' respectively.

The UK albimanus group however, which depends on the whitish or bronzish abdominal markings (as opposed to yellow in other species) could not be reconciled with a wider taxonomy from the literature. It is handy for recording convenience in the UK - but breaks down quickly under the weight of overseas species, and is not taxonomically meaningful anyway. 'Section P. albimanus' in iNat is a completely different concept. In fact 'Section P. albimanus' in iNat includes 'Complexes clypeatus and scutatus' (Which is why we had to use Sections and Complexes to implement these groups). In addition, two species of the UK albimanus group are not in 'Section P. albimanus' (P ambiguus and discimanus). Here is how it looks:

Genus Platycheirus
---Subgenus Pachysphyria (inc. ambiguus - this whole Subgenus is characterised by a curled apical bristle on the male forefemur)
---Subgenus Platycheirus (inc. everything except ambiguus)
------Section P peltatus (same as the UK group)
------Section P manicatus (=UK group + discimanus)
------Section P albimanus (=albimanus, sticticus and the two complexes mentioned below)
---------Complex P scutatus (same as UK group)
---------Complex P clypeatus (same as UK group)

Another way to look at this is:
If you know the UK group
you can give it the same ID on iNat unless there is a possibility that it is ambiguus or discimanus.
If you have an ID from iNat, the UK group will be the same unless the ID is albimanus-group and the spots are not grey, or the ID is manicatus-group and the spots are grey (but the latter case is unlikely to occur in practice).

I hope that makes some sense. I have intended to put out a key to help with this, but it will have to wait. Maybe not long...

Posted on October 17, 2022 08:35 PM by matthewvosper matthewvosper | 0 comments | Leave a comment

July 16, 2022

Key to the Eriozona, Leucozona and Flavizona of the World

Well this has turned out to be a challenging group!

Here we have a cluster of genera that contain the Syrphine bumblebee mimics, and a bunch of things with white markings. They're cool, and not so common. In fact many of them are very obscure. A lot of this key is based on verbal descriptions alone - and sometimes not very detailed ones at that - so it needs to be treated with considerable care.

Species included:
Eriozona:
analis, nigroscutellata, syrphoides, tricolorata

Leucozona (Leucozona)
americana, brunetti, flavimarginata, inopinata, kingdonwardi, lucorum, nigripila, pruinosa, virendra

Leucozona (Ischyrosyrphus)
beybienkoi, glaucia, laternaria, sivae, transifasciatus, ussuriensis, velutina, xylotina

Flavizona
dolichostigma

Posted on July 16, 2022 11:03 PM by matthewvosper matthewvosper | 9 comments | Leave a comment