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Re: Mesozoic birds made insects shrink

David Marjanovic <david.marjanovic@gmx.at> wrote:

>>  Giant aeschnidiid dragonfly larvae have been found in the Yixian
>>  Formation.
> How big? *shudder*

Well, "giant" by insect standards.  :-)

There are at least two refs (Fleck et al., 2002; Palaeontol. 45:
165-184 and Zhang, 1999; Cret. Res. 20: 813–827) that describe
dragonfly larvae (Aeschnidiidae) from the Jehol biota.  These larvae
measure up to around 76 mm in body length (excluding terminal
appendages), although one undescribed specimen is mentioned as being
closer to 100 mm.

There are adult dragonflies from the Late Jurassic lithographic
limestones of Germany that had wingspans of between 190 and 220 mm,
such as _Urogomphus_ and _Aeschnogomphus_.  I can't help but think
that these kind of mega-insects were eaten by _Archaeopteryx_...
although if _Archaeopteryx_ targeted winged adults while they were
airborne, I wonder how it caught them.

BTW, these Mesozoic dragonflies belong to the true Odonata, rather
than to the Protodonata (or Meganisoptera) that includes the giant
Carboniferous "griffinfly" _Meganeura_.