AQUATIC BIRDS FROM THE UPPER CRETACEOUS (LOWER CAMPANIAN) OF SWEDEN AND THE BIOLOGY AND DISTRIBUTION OF HESPERORNITHIFORMS.

Isolated skeletal elements of three hesperornithiform taxa are recorded from marine strata of latest early Campanian ( sensu germanico) age in the Kristianstad Basin, southern Sweden. The material comprises Hesperornis rossicus Nessov and Yarkov, one of the largest Mesozoic aquatic birds known to date, Hesperornis sp. and Baptornis sp. The holotype (a dorsal vertebra) of Parascaniornis stensioei Lambrecht is re-examined, and the nominal species is here considered as a nomen dubium because no diagnostic features can be found that separate the type from dorsals of Baptornis advenus. The distribution and palaeobiology of hesperornithiforms are reviewed. [ABSTRACT FROM AUTHOR]