My interests include the evolution, life history, and systematics of externally shelled cephalopods, particularly the twin groups-the ammonoids and nautiloids. Both have a superb fossil record comprising about 10,000 species. The ammonoids arose in the Devonian period and attained a high level of diversity in the Mesozoic Era, becoming extinct at the end of the Cretaceous Period. The nautiloids had a spectacular radiation in the early Paleozoic Era. They declined thereafter, although they have persisted into the Recent as the genus Nautilus. Both groups preserve in their shells a record of their ontogeny. Study of their ontogeny, based on material collected from Morocco and elsewhere, reveal unique characters that help define each of the groups.

My investigations have focused on the early ontogenetic development of ammonoids and nautiloids, and how this information can be used to reconstruct the phylogeny of these groups. I also study the evolution and systematics of ammonoids from Upper Cretaceous rocks of the Northern Great Plains in the United States. Fieldwork in Montana, South Dakota, and Wyoming has resulted in an extensive collection of fossils from a group of ammonoids known as scaphites, which were plentiful in the seaway that once covered this part of North America during the Cretaceous Period. In addition to their systematics, I study the distribution of these species in time and space, and in relation to their paleoenvironment.

Recent work on the Atlantic Coastal Plain, including Maryland and New Jersey, has also yielded a surprising number of ammonite fossils. These fossils are very useful for biostratigraphic analysis, in correlating strata between the Western Interior and northern Europe. Of special interest is the study of Cretaceous/Tertiary boundary sections in New Jersey, which are rich in ammonites.

All of this research depends on field work and involves annual expeditions to the Northern Great Plains (Wyoming, South Dakota, and Montana) and, in addition, the Atlantic and Gulf Coastal Plains (New Jersey, Delaware, Maryland, Alabama, and Tennessee). More recently, these trips include parts of Western Europe (Poland). I have also collected Nautilus in Palau, Fiji, and New Caledonia, as part of a large study on the phylogeny of these cephalopods.

Landman, N.H., D.S. Jones, and R.A. Davis. 2001. Hatching depth of Nautilus pompilius in Fiji. The Veliger 44(4): 333-339

Cochran, J.K, N.H. Landman, K.K. Turekian, A. Michard, and D.P. Schrag. 2003. Paleoceanography of the Late Cretaceous (Maastrichtian) Western Interior Seaway of North America: evidence from Sr and O isotopes. Palaeogeography, Palaeoclimatology, Palaeoecology 191: 45-64.

Tanabe, K., N.H. Landman, and Y. Yoshioka. 2003. Intra- and interspecific variation in the early internal shell features of some Cretaceous ammonoids. Journal of Paleontology 77(5): 876-887.

Landman, N.H., R.O. Johnson, and L.E. Edwards. 2004. Cephalopods from the Cretaceous/Tertiary Boundary Interval on the Atlantic Coastal Plain, with a Description of the Highest Ammonite Zones in North America. Part 1. Maryland and North Carolina. American Museum Novitates 3454: 64 pp.

Landman, N.H., R.O. Johnson, and L.E. Edwards. 2004. Cephalopods from the Cretaceous/Tertiary Boundary Interval on the Atlantic Coastal Plain, with a Description of the Highest Ammonite Zones in North America. Part 2. Northeastern Monmouth County, New Jersey. Bulletin of the American Museum 287: 1-107.

Tanabe, K., C. Kulicki, and N.H. Landman. 2005. Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids. Acta Palaeontologica Polonica 50(1): 9-18.

Landman, N.H., C.J. Tsujita, W.A. Cobban, N.L. Larson, K. Tanabe, and R.L. Flemming. 2006. Jaws of Late Cretceous Placenticeratid Ammonites: How Preservation Affects the Interpretation of Morphology. American Museum Novitates 3500: 1-44.

Landman, N.H., and A. Grebneff. 2006. Jaws of Triassic ammonoids from New Zealand. New Zealand Journal of Geology and Geophysics, vol. 49: 121-129.