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Stratiomyidae question
Calilasseia	#1 Posted on 10-08-2015 03:42
Member Location: Near Liverpool, UK Posts: 90 Joined: 20.09.11	I've noticed that numerous members of the Stratiomyidae featured in the Gallery have backward pointing spines emanating from the scutellum. Is this feature diagnostic of this Family? Is the arrangement and number of spines considered by the experts to be diagnostic to Tribe or Genus level? The reason I ask what some may consider to be an elementary question (I am after all an amateur Dipterist), is that in accounts of Stratiomyid taxonomy, I cannot recall seeing this feature being mentioned. Much is devoted towing venation and antennal structure (which of course are important diagnostic features for many taxa right across the Diptera), but I find it puzzling that a feature as easy to spot in the field as this, seems to have received no attention in the admittedly few examples of the literature I've read. If a specialist in this clade can enlighten me, I'll be grateful.


rvanderweele	#2 Posted on 10-08-2015 05:24
Member Location: Zoelmond, the Netherlands Posts: 1984 Joined: 01.11.06	The number of spines varies. Some have more than 2, some have 2 and some none at all. It is, thus, not diagnostic of the family. ruud van der weele rvanderweele@gmail.com


Carlo Monari	#3 Posted on 10-08-2015 07:21
Member Location: Milan, Italy Posts: 240 Joined: 28.04.11	It is not diagnostic at family level, but it can be used, maybe with other characters, to separate subfamilies (e.g. more than 2 -> Beridinae). Best regards, Carlo


rvanderweele	#4 Posted on 10-08-2015 13:56
Member Location: Zoelmond, the Netherlands Posts: 1984 Joined: 01.11.06	Not all Beridinae have more than 2 spines, though this is valid in the UK. I know in Hungary, genus Allognosta has no spines at all. Anyway, in general it cannot be used as diagnostic in Europe. ruud van der weele rvanderweele@gmail.com


Carlo Monari	#5 Posted on 10-08-2015 21:32
Member Location: Milan, Italy Posts: 240 Joined: 28.04.11	I agree; that character alone can't be used for a complete determination. But I would like to know if my previous statement is correct or not: in other words, are there Stratiomyidae with more than two spines on the scutellum which are not Beridinae? If yes, what I said is wrong, otherwise it is correct even if it does not characterize all the Beridinae. Best regards, Carlo


rvanderweele	#6 Posted on 11-08-2015 16:12
Member Location: Zoelmond, the Netherlands Posts: 1984 Joined: 01.11.06	No, it is not correct. For example Antissa of subfamily Antissinae, which occurs in the neotropics, has also more than 4 spines. But also some Pachygasterinae have more than 2 spines on the scutellum ruud van der weele rvanderweele@gmail.com


Carlo Monari	#7 Posted on 11-08-2015 18:27
Member Location: Milan, Italy Posts: 240 Joined: 28.04.11	Thanks Ruud. One last question: is it valid for some local faunas? I read that it should be valid for French and Italian Stratiomyidae, but now I am no more sure. Best regards, Carlo


rvanderweele	#8 Posted on 11-08-2015 18:35
Member Location: Zoelmond, the Netherlands Posts: 1984 Joined: 01.11.06	for some local fauna, sure! In the Netherlands yes. I guess also for France and Italy, but I am not 100% sure ruud van der weele rvanderweele@gmail.com


Paul Beuk	#9 Posted on 12-08-2015 10:04
Super Administrator Location: Netherlands Posts: 19225 Joined: 11.05.04	And there are other families with spines, too. Check, for example, Coenomyia ferruginea... Paul - - - - Paul Beuk on https://diptera.info


Calilasseia	#10 Posted on 13-08-2015 15:45
Member Location: Near Liverpool, UK Posts: 90 Joined: 20.09.11	And this is why I consult the experts. Many thanks for illustrating this principle once again. I've learned several new pieces of data as a result. Keep up the good work everyone!