Hank – Juvenile Maiasaura peeblesorum Skeleton

An exceptionally rare juvenile Maiasaura skeleton from the Two Medicine Formation of Montana.

Overview

Hank is a fully mounted juvenile Maiasaura peeblesorum, prepared and mounted under the scientific direction of Dr. Frédéric Lacombat, and the younger of the two growth stages offered here. He is offered with the adult, Koda.

A maiasaur is a hadrosaur — a large, duck-billed plant-eater that lived in herds on the floodplains of Late Cretaceous Montana. Maiasaura translates as “good mother lizard”, a name referencing evidence of nesting and parental care within the species — a discovery that changed the understanding of dinosaur behavior.

The name follows the 1979 description of the first known hadrosaurid nest, found in Montana with young animals preserved inside it — a study since characterized in the scientific literature as revolutionary in its inferences about family life in a non-avian dinosaur. Research has continued in that direction. A 2025 study in Scientific Reports, co-authored by the paleontologist who named the species, found that newly hatched Maiasaura were comparable to birds that hatch helpless and depend on their parents. The same study concluded that the young stayed in the nest for weeks after hatching. A 2026 study of tooth wear found that juveniles and adults ate differently, which the authors take as evidence that the young were being fed and nurtured.

The Deposit

The Linster Quarry, near Bynum in Teton County, Montana, lies within the Two Medicine Formation and is a Maiasaura bonebed, laid down on a dynamic seasonal floodplain. The deposit is interpreted as the result of two events: a herd drowned in a local flood, and the animals decomposed and disarticulated where they lay; the remains were then moved and concentrated by a second, gentler event, strong enough to transport and stack the bones but not to damage or erode them, and occurring before significant predation or surface weathering. The hadrosaur material recovered from the Linster Quarry is attributed exclusively to Maiasaura, with McFeeters, Evans and Maddin noting that “there is no evidence for a second hadrosaurid taxon in this bonebed.” The significance of the site is well established in the paleontological literature. A 2021 study in Acta Palaeontologica Polonica described five partial Maiasaura skulls from the Linster Quarry bone bed, spanning subadult to mature adult.

A bonebed is what makes a growth series possible: the same event that mixed the material is why an adult and a juvenile of one species can be offered from a single site as a sequence of specimens representing different stages of the animal's development.

Discovery

Hank was excavated from the Linster Quarry by the Linster family, who worked the site from the 1990s until 2005. It was on this same ground, in 1993, that Wes Linster discovered the defining specimen of Bambiraptor feinbergi, upon which the species was formally described in 2000 by a team including Philip Currie, Robert Bakker and John Ostrom. Hank's preparation and mounting were carried out in France under the scientific direction of Dr. Frédéric Lacombat.

Preparation and Restoration

Hank is mounted on a custom-fabricated steel armature. The specimens prepared from this deposit were posed in relation to one another; each mount stands on its own base, so that relationship exists when they are installed together. Where original bone is absent, elements have been fabricated by 3D printing integrated with epoxy resin. A complete bone list identifies, element by element, original fossil bone against restored and printed material.

Growth Stage

Judging from the delicate, fine nature of the bone structure, and from the overall size and degree of bone development, it can be determined that the skeleton represents Maiasaura peeblesorum at a juvenile stage of growth. Juvenile bone is less likely to survive fossilization than adult bone, and histological research on the species — a study of fifty Maiasaura tibiae — found mortality to be very high in the first year of life.

Growth stage in fossil vertebrates is determined from skeletal morphology — overall size, degree of bone development, and fusion of skeletal elements — assessed against published ontogenetic studies of the species.

Completeness and Condition

Hank is a composite. The animals in this deposit came apart before the bones were moved and stacked together, so no element can be assigned with certainty to one individual rather than another. The mount is assembled from original Maiasaura peeblesorum bone recovered from the Linster Quarry and prepared as a single juvenile skeleton under the scientific direction of Dr. Frédéric Lacombat.

Of the mounted skeleton, 62% is original fossil bone by bone count. The specimen has been professionally prepared and mounted and is offered ready for display.

Scientific Assessment

"The scientific relevance of these Maiasaura specimens is based on the historic Linster Quarry, and the incredible abundance of bones from multiple growth stages, from juvenile to adult, of a single dinosaur species. Bone beds like this offer critical ontogenetic information that allows for comprehensive comparative study. Hadrosaurid growth, development and pathologies have been revealed through fossils from this site. The preparation and mounting combine expert craftsmanship through elegant fabrication of the armature and accurate skeletal articulation. This study mount style preserves scientific fidelity and provides curatorial support to ensure stable long-term display. These composite skeletons from one of the most well-known bone beds of the Cretaceous period are a perfect representation of science and discovery."

Andre LuJan, Paleontology Expert

Collecting Significance

Hank is the younger of two Maiasaura offered here from the same deposit. Read against the adult in the following lot, he makes it possible to see how the species changed as it grew — in the proportions of the limbs, the development of the skull, and the way the animal moved as it matured.

Maiasaura figures prominently in the scientific literature on hadrosaur growth and population biology. That work depends on material from across the growth range, and the youngest stages are the hardest to come by: juvenile bone is less likely to survive.

While Maiasaura is one of the best understood hadrosaurs, specimens are rare to encounter — and juvenile examples rarer still.

Hank stands 13 feet long and 6.3 feet tall, an intimate scale for a fully mounted dinosaur. At that height a visitor meets him almost eye to eye.

Offered with full title and license; all intellectual property transfers with the specimen.

Provenance

Excavated by the Linster family from the Linster Quarry, Two Medicine Formation, Teton County, Montana

Cliff and Sandra Linster, Bynum, Montana

Acquired in December 2005 with the property and the excavated fossil material

Supporting Archive

Original historical documentation includes:

— documentation relating to the land and its ownership

— documentation relating to the quarry and the excavation

— a complete bone list and osteograph for the mounted skeleton

Available on request. To view a PDF dossier that includes these materials, please contact a specialist.

References

On the deposit and the species:

McFeeters, B., Evans, D.C., and Maddin, H.C., “Ontogeny and variation in the skull roof and braincase of the hadrosaurid dinosaur Maiasaura peeblesorum from the Upper Cretaceous of Montana, USA”, Acta Palaeontologica Polonica, vol. 66, no. 3, 2021, pp. 485–507.

Burnham, D.A., Derstler, K.L., Currie, P.J., Bakker, R.T., Zhou, Z., and Ostrom, J.H., “Remarkable new birdlike dinosaur (Theropoda: Maniraptora) from the Upper Cretaceous of Montana”, The University of Kansas Paleontological Contributions, new series no. 13, 2000.

Woodward, H.N., Freedman Fowler, E.A., Farlow, J.O., and Horner, J.R., “Maiasaura, a model organism for extinct vertebrate population biology: a large sample statistical assessment of growth dynamics and survivorship”, Paleobiology, vol. 41, no. 4, 2015, p. 503.

Bert, H., Woodward, H., Rinder, N., Amiot, R., Horner, J.R., Lécuyer, C., Sena, M., and Cubo, J., “Neonatal state and degree of necessity for parental care in Maiasaura based on inferred neonatal metabolic rates”, Scientific Reports, vol. 15, 2025, article 24827.

Hunter, J.P., and Janis, C.M., “Tooth wear in juvenile and adult hadrosaurs: implications for parental care in Maiasaura”, Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 690, 2026, article 113707.

Horner, J.R., and Makela, R., “Nest of juveniles provides evidence of family structure among dinosaurs”, Nature, vol. 282, no. 5736, 1979, pp. 296–298.