The animals in this group range in size from 0.6 mm to 300 mm, and inhabit the ocean from the intertidal to the deep sea. Large scale evolutionary questions on change in size and associated modification of the body, as well as colonization of the ocean in the vertical dimensions are addressed.

Geiger is the leading authority on the world's abalone, author of a monograph of this family, and maintains a website on this family. He is working on a second monograph on the little-known, microscopic little slit shells (Scissurellidae s.l.). He has discribed 33 species and six genera (List).

Historical aspects of science are an other area of interest. A facsimile reproduction and translation of the exceedingly rare sales catalog by Anton August Heinrich Lichtenstein (1794) is available on the web, along with some select facsimile pdfs of other rare works on mollusks.

Selected publications:

Geiger, D. L., B. Marshall, W. Ponder, T. Sasaki & A. Warén. 2007. Techniques for collecting, handling, and preparing small molluscan specimens. Molluscan Research 27 (Special Issue): 1-50.

Geiger, D. L. 2006. Eight new species of Scissurellidae and Anatomidae (Mollusca: Gastropoda: Vetigastropoda) from around the world, with discussion of two new senior synonyms. Zootaxa 1128: 1-33.

Geiger, D. L. & C. E. Thacker. 2005. Molecular phylogeny of Vetigastropoda reveals non-monophyletic Scissurellidae, Trochoidea, and Fissurelloidea. Molluscan Research 25: 47-55.

Geiger, D. L. 2003. Phylogenetic assessment of characters proposed for the generic classification of Recent Scissurellidae (Gastropoda: Vetigastropoda) with description of one new genus and six new species from Easter Island and Australia. Molluscan Research 23: 21-83.

Geiger, D. L & G. T. Poppe. 2000. Haliotidae. in Conchological Iconography. G.T. Poppe & K. Groh (eds.). Conchbooks, Hackenheim. 135 pp., 83 pls.

For more information, see:
Geiger's CV and full publications list with pdfs
ABMAP: Abalone Mapping Project
Lichtenstein (1794) catalog