Although I grew up a long way from the ocean in upstate New York, I became fascinated with marine invertebrate fossils that are abundant in the rocks of that region, and by the time I was in high school had decided on a career in paleontology. I studied geology at the University of Michigan, received my B.S. there in 1966, and then went to Yale for my Ph.D., finishing in 1970.

Although my degree is in geology, my dissertation concerned the life habits and ecology of living feather stars (crinoid echinoderms) on coral reefs in the Caribbean. Up to that time, very few researchers had ever examined living crinoids in the wild, yet paleontologists working on fossil crinoids needed better knowledge of how these animals live. Subsequently the study of crinoids, both living and fossil, has been the main focus of my research.

A post-doctoral with the Smithsonian took me to Panama, and led to my first job, doing long-term monitoring of nearshore reef communities and environmental conditions. In 1972 I participated in research using the Nekton Gamma submersible in Jamaica during which the first submersible observations of deep-water stalked crinoids were made. In 1975 I joined the geology faculty at the University of Cincinnati, again far from the ocean, but situated on some of the richest fossil-bearing strata in North America.

I’ve been very fortunate to study fossil crinoids ranging in age from Ordovician (440 million years old), to Cretaceous (85 m.y. old) and Eocene (over 30 m.y. old), as well as living forms. My work on living crinoids has taken me to the Caribbean, Great Barrier Reef, Indian Ocean, and the NE Pacific. Besides crinoids, my research interests include coral reef ecology (aspects of the mass mortality of long-spined sea urchins in the 1980s, hurricane damage to reefs) and taphonomy (processes affecting fossil preservation). At Cincinnati I enjoy teaching courses in paleontology, paleoecology, dinosaurs, and coral reefs.

ABSTRACT: Feather Stars and Sea Lilies in the Wild

Feather stars and sea lilies make up the Crinoidea, the most ancient living members of the echinoderm phylum, along with other echinoderm classes the sea stars, brittle stars, sea urchins, sand dollars, and sea cucumbers. There are over 80 living species of stalk-bearing sea lilies and about 540 living species of stalkless feather stars (comatulids). Fossil crinoids amount to over 6000 species. Crinoids are found over a wide depth range in all modern ocean realms, but reach their peak diversity on shallow Indo-Pacific reefs.

This presentation will feature color images from direct observations of crinoids by SCUBA and submersibles. All crinoids live as passive suspension feeders, heavily dependent on persistent currents to bring food to the awaiting tube feet arrayed in filtration fans of the arms and pinnules. On coral reefs feather stars prefer current-exposed promontories, forereef slopes, and seaward edges of shallow reef platforms. Stalked crinoids are restricted to depths below 100 m and also prefer current-swept habitats. Crinoids prefer uniform temperatures and normal marine salinities, in addition to favorable water movement. Their food consists of phytoplankton, zooplankton, and particulate organic matter.

Reef-dwelling crinoids are preyed upon by fish such as triggerfish, and often show damage and regeneration to the arms and visceral mass. Anti-predator defenses include spinose morphology, cryptic or nocturnal habits, and possibly distastefulness or toxicity. Crinoids are hosts to a wide variety of symbionts, including shrimp, crabs, polychaetes, and even fish. In reproduction, crinoids release gametes, sometimes in mass spawnings, and following external fertilization, a larva develops that settles to the sea floor after a brief sojourn in the plankton. Comatulids are attached by a larval stalk for a brief period after settlement, but break free as adults and are capable of either crawling or swimming using the arms.

The longevity of crinoids is poorly known, although long-term observations suggest that individuals remain at the same perch and may live for years or even decades. Documentation of a recent sharp decline in numbers of some reef species in the Caribbean may be in part a consequence of over-collecting for the aquarium trade.