Steve Jabo

Clamshell storage jackets have been used successfully to conserve vertebrate fossil specimens for three decades. While basic principles – a two part shell with inner padding – maintain,  techniques have advanced as practitioners explore new methodologies.

Non-reactive, archival grade materials are now used throughout. The outer shell is no longer built atop a clay spacer. Instead, plaster is applied directly to a pre-tailored polyester felt or polyethylene foam liner. Multiple strategies for binding liners have also been established, including sewing, hot-gluing, and welding foam with a heat gun. Offsetting a 1/4" foam liner on one side of the jacket has been found to provide tighter closure. Internal polyethylene foam structures have replaced metal supports. When foam struts and feet are covered with fiberglass and plaster, they effectively form rigid tubes capable of supporting the specimen. In 2014 a technique was pioneered at the Smithsonian NMNH where semicircular "rockers" carved from polyethylene foam plank are wedded to the shell. This allows large jackets to be flipped over with minimal effort

These advances produce jackets with increased long term stability, reduce production time and materials, and make the specimens easier and safer to handle. The elimination of embedded metal permits CT scanning of the specimen in-jacket, ensuring the fossil is supported at all times.

A survey of the Dinosaur Hall at the Smithsonian's Natural History museum identified several vertebrate exhibit mounts in need of conservation. Antiquated mounting techniques, had combined with heat, humidity and the high traffic flow of visitors in the hall to create an unstable environment for some of our inherently fragile specimens. In an ongoing effort to protect and restore these display fossils, Triceratops was restored in 2001, and Stegosaurus stenops (USNM 8612) was removed from exhibit in Spring 2002.
The mount, created by Charles Gilmore 85 years ago, had the bones resting in direct contact with their metal armature, commonly attached by screws drilled directly into the elements. Deterioration of the fossils was marked by bone fragments frequently found on the floor under the mount, broken bones held together solely by their armature, and repairs documenting multiple breaks in many bones. Upon removal from exhibit, each bone was repaired, restored, molded, and cast. Experiments with different materials led to new molding techniques. In addition to replicating the existing elements, preparators sculpted, molded, and cast throat ossicles missing from the original mount. Hollow hydrocal gypsum cement casts, reinforced with fiberglass cloth were filled with 8-pound expanding foam and remounted with an internal armature in June 2003. This new mount is not only more anatomically accurate than its predecessor, but more responsive to its display environment. Stegosaurus is now posed in a reactive stance in front of our Allosaurus, which now seems prepared to attack.
Once the bones were molded, they were returned to the collections where they are being fit into custom padded jackets. All of the dermal plates that would not fit into padded drawers are now cradled. These conservation efforts provide protection as well as added accessibility to research staff and visitors and we are now focused on rehabilitating our Camptosaurus specimens.

In 1997, a new microvertebrate site was discovered in the upper part of the Upper Jurassic Morrison Formation near Shell, Wyoming.  The site occurs in a highly weathered, floodplain succession of red and green mottled silty claystone near the top of a ravine.  Fossils are concentrated within two distinct layers.  The primary layer is dominated by dinosaur eggshell fragments and contains the majority of the vertebrate material.  Teams from the Smithsonian Institution began working the site in 1999, and have since excavated a number of matrix blocks from a 2 x 3 m quarry. Numerous specimens were removed directly from the quarry face in the field, and loose samples were dry-screened at the site.  Manual and dissolution preparation continues on the collected samples, and has already revealed a rich vertebrate fauna.

Although no intact eggs have been found, the presence of large eggshell pieces, some in close contact with one another, suggest that their source was nearby.  Based on eggshell morphology and microstructure, the eggs appear to derive from ornithopod dinosaurs.  The well-preserved bone remains are dominated by teeth, limb shafts, and vertebrae.  Teeth from a multituberculate, a symmetrodont, and a possible eupantothere hint at a diverse mammalian fauna.  Several dinosaur taxa are present, including one theropod tooth with troodontid-like denticles.  A sphenodontian is indicated by the presence of associated jaws and cranial elements.

Microvertebrate remains are not common in the Morrison Formation, and this site brings important new information about Late Jurassic mammals and reptiles. The likelihood that little transport has occurred strengthens inferences of taxon associations within at least one type of Morrison environment, and holds the potential for elucidating new paleoecological information as well.

The Smithsonian Institution, through a grant from the Smithsonian Women's
Committee, implemented a programme during the fall and winter of 2008 to teach
the basics of mechanical fossil preparation, moulding and casting to individuals
seeking to work as volunteer preparators in the National Museum of Natural
History's exhibit preparation lab, called FossiLab. Four outside preparators were
contracted to conduct the instruction; two instructors taught two five-day sessions
on molding and casting and two other instructors taught two six-day sessions on
preparation. The Department of Paleobiology's (Paleobiology) curatorial staff
instructed the groups in paleobotanical preparation and microfossil processing and
picking. All instruction took place in FossiLab during public hours.
Registration for the programme was conducted via the department's web page where
a detailed description of the work and the lab familiarized prospective students with
the type of work they would be performing. They were also asked a series of selfevaluative questions in an attempt to filter out those who might not have the innate
motor skills or temperament needed for the job. Those who were confident in their
decision to volunteer were interviewed in FossiLab, and the majority of those then
registered for the programme.
Twenty nine people, some new and some experienced, were trained. FossiLab is
now staffed each day by as many as six volunteer preparators who perform a variety of tasks for Paleobiology. The number of weekly person-hours has tripled since
the training. Continued, focused training on individual projects is carried on by the
Vertebrate Paleontology Preparation Laboratory staff. Eighteen hours of videotape
was recorded during the training and will be edited and made available via DVD and
the internet.