Posted by Louis Boumans on 09-08-2004 22:00
#1
LS,
Another topic that doesn't really fit into any of the forum categories...
but sth i'd like to share with you, and maybe some of you know more about this phenomenon.
About a week ago i found a
Chloromyia formosa - Stratiomyidae, cf pictures in one of the identification requests - female that had an additional front tarsus. I.e. a small tarsus developed next to the normal one, so the leg is ramified below the tibia.
I suppose this is due to some disorder in embryonic development, comparable with an extra finger in vertebrates. Though i don't really think it is a likely explanation, i had to think of an atavism, as crustaceans typically have ramified appendages.
Does anyone know more about it?
Louis
Posted by Paul Beuk on 10-08-2004 10:14
#2
Dear Louis,
I have found similar aberrations in several groups (Drosophilidae, Formicidae) but do not yet know anything about the cause. It must be different form the addition of a finger in vertebrates, since that is something wrong in the ontogeny. In these insects it is something going wrong during metamorphosis, since the tarsus per se did not exist when metamorphosis began. I assume it has to do with a disturbance of the pupa at some point during the pupal stage. Similarly, there may be aberrations in wing veneation and abdominal segmentation.
Paul