Non-jumping plant-lice in Cretaceous amber (Hemiptera: Sternorrhyncha: Psylloidea)

Liadopsylla apedetica sp.n. Ouvrard, Burckhardt & Azar and L. hesperia sp.n. Ouvrard & Burckhardt are described from Lebanon and New Jersey amber, respectively, constituting the first descriptions of Psylloidea preserved in Cretaceous amber. Liadopsylla hesperia is the first representative of Liadopsyllidae found in the New World. Liadopsylla apedetica is remarkably well preserved, showing conical, mobile metacoxae. This suggests that Liadopsyllidae did not jump the way extant psyllids do. It is proposed that enlarged metacoxae fused with the complex metathoracic furcae constitute a synapomorphy of extant Psylloidea. This trait was first observed in fossils from the Eocene. As such, the inability to jump in a few extant members of Psylloidea is a secondary loss that probably occurred several times independently. The families Liadopsyllidae and Malmopsyllidae are also redefined; within Liadopsyllidae, the genus Mesopsylla is synonymized with Liadopsylla. The origin and palaeobiogeography of the Liadopsyllidae are briefly discussed.