SCORPIONS FROM THE VISEAN OF EAST KIRKTON, WEST-LOTHIAN, SCOTLAND, WITH A REVISION OF THE INFRAORDER MESOSCORPIONINA

Scorpions from East Kirkton Quarry are represented by abundant cuticle fragments and rarer articulated specimens. Cuticles isolated from the ir matrix are exquisitely preserved, permitting this fauna to be descr ibed in more detail than other Carboniferous scorpion faunas. Most of the material is attributed to Pulmonoscorpius kirktonensis n. gen. n. sp. Specimens possibly indicating the presence of two additional Pulmo noscorpius species are referred to under open nomenclature. Rare fragm ents of an aquatic 'archaeoctonoid', and an orthostern scorpion, also occur. Most specimens of Pulmonoscorpius are juveniles. The range of t aphonomic effects observed in these and larger individuals suggests th at, as a consequence of poor preservation, the morphology of some Uppe r Palaeozoic scorpions has been misinterpreted by previous workers. Wi thin the infraorder Mesoscorpionina two groups are recognised. These a re distinguished by the position of the posterior pair of coxae. Pulmo noscorpius n. gen. belongs to group A, in which the posterior coxae ab ut the sternum. This group includes the known Lower Carboniferous meso scorpions and ranges from the Upper Devonian to the Upper Carboniferou s. All group-A mesoscorpions are reviewed here. In group-B mesoscorpio ns the posterior pair of coxae apparently abut the genital opercula, b ut confirmation of this derived character and formal taxonomic recogni tion of these groupings must await a restudy of the group-B mesoscorpi ons, which are known from the Upper Carboniferous and Triassic.