The fourth volume of the Eisenack Catalog, New Series contains mostly species first described in a suite of recent Australasian publications. Unless included in an earlier volume, all new species in the following publications are covered here: Backhouse, 1987, 1988; Bint, 1988; Davey,1988; Helby, 1987; Marshall, 1988, 1989, 1990a, 1990b; May et al., 1987; McMinn, 1988; Parker, 1988; Stevens, 1987; Stevens and Helby, 1987; Stover and Helby, 1987a, 1987 c, 1987d; Wilson, 1984a, 1984b, 1984c, 1988. This volume also contains "type species" of genera based on Australasian material and not included in Volumes 2 or 3, as well as two subspecies of Gochteodinia villosa inadvertently omitted from Volume 3 and a revision of the generic entry for the genus Moorodinium, incorrectly rendered as "Mooradinium" in Volume 1.
The information in this volume, especially that pertaining to holotype location and type material, has been reviewed by Australasian researchers John Backhouse, Robin Helby and Graham Wilson. In some cases this has led to revisions from the original publication, and where appropriate such changes are identified in the text. The present authors are grateful for these valuable reviews.
As in previous volumes, the format of the Type Occurrence section is formally structured. Where possible, type occurrence information is compartmentalized into separate geographic, lithostratigraphic and geochronologic statements, separated by semi-colons. For example, in Volume 3 the Type Occurrence for Xylochoarion hacknessense is given as "Hackness, Yorkshire, England, U.K.; Hackness Rock; Quenstedtoceras lamberti Zone, Late Callovian, Jurassic." This implies that the type material of the species is from Hackness, is derived from the Hackness Rock, and is of Late Callovian age. It is not stating that the Hackness Rock is a Late (sic) Callovian lithological unit - it is of course an Upper Callovian lithological unit.