- Xyelidae
Taxobox
image_size = 230px
image_caption = "Xyela" theType genus of Xyelidae. From "British Entomology ".
name = Xyelidae
fossil_range=Triassic - Recent
regnum =Animal ia
phylum =Arthropoda
classis =Insecta
ordo =Hymenoptera
subordo =Symphyta
superfamilia =Xyeloidea
familia = Xyelidae
subdivision_ranks = Genera
subdivision = see textThe Xyelidae is a small family of
sawflies known from fewer than 50 extant species in 5 genera, but with an extensivefossil record ; they are the oldest fossilHymenoptera , dating back to theTriassic , some 200 million years ago. Most species occur in the Northern Hemisphere, especially inboreal regions, though there are a fewneotropical species. Most are associated withconifer s (esp. "Pinus " and "Abies "), where thelarva e feed onpollen or within buds, though larvae of a few species feed on the leaves ofdeciduous trees.The family is characterized by the appendages of the head, which are truly remarkable in that the antennae and palpi are nearly leg-like in structure, with a long basal segment followed by a series of tiny segments, as in the tibia-tarsus. It is tempting to speculate that there is a
homeobox -gene explanation for this unusual anatomy, as mutations of this gene region in other insects can cause the mouthparts and antennae to become leg-like.Extant genera
*"
Macroxyela " Kirby, 1882
*"Megaxyela " Ashmead, 1898
*"Pleroneura " Konow, 1897
*"Xyela " Dalman, 1819
*"Xyelecia " Ross, 1932
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