Paleo Terrarium

This Model Ecosystem project interprets evolution, ecology and environmental change concepts with a terrarium planting recreating a Late Cretaceous (68 million years before present) North America forest. The roomy (85 gallon [322L]) glass enclosure will house plants that grew in this ancient landscape, while diorama elements will represent a part of the non-avian dinosaur fauna.

Flora selected for the planting include groups that still survive in our era, but represent very old evolutionary lineages and were more abundant during the Age of Dinosaurs:

  • Calocedrus Incense Cedar - This evergreen tree plays the role of vast conifer forests that grew before Angiosperms (the flowering plants) became the dominant flora all around. While Calocedrus is a canopy tree that reaches 200 feet (60 meters) in height, it can grow well indoors under moderate light and can be pruned like a bonsai to control its size.
  • Gnetum gnemon - This very unusual small tree resembles a Coffee bush, but is in fact a Gymnosperm that survives today as a relic of an evolutionarily old group.
  • Pharus Grass - This is one of the most evolutionarily basal of true grasses. With broad leaves, it looks more like a Ginger or similar tropical plant and may resemble the earliest of grass species.
  • Polystichum Rock Fern - Ferns are among the oldest of living plant groups. This selection grows well in terrariums and, repeated as several individual clumps, creates a soft terrarium groundcover layer.
  • Zamia Cycad - With fossils more than 300 million years old, the Cycad lineage extends into the deep past, The species selected for this project, Zamia vazquezii, is easy to grow and stays smaller than most others.

The tank currently has a floor lining of simple light diffuser panel. This material will be elevated with spacers to create a drainage layer, then covered with a high-drain soil medium ready for planting. After plants are arranged, a forest floor leaf litter will be added to cover the soil layer for a natural appearance. Thee or five slender Cedar tree trunks (representing the fossil conifer tree canopy) will be positioned as features to develop the vertical dimension, while the growing plants fill out this effect. The pair of shots below shows a terrarium display of similar construction, the Dojō Terrarium style, in a smaller (37 gallon [140L]) tank with a trio of Birch stems zip-tied in place and with the plants and other elements added in following steps.


A replica ground nest will represent dinosaurs in this living display. Recent discoveries gleaned from fossils unearthed in Canada has found the smallest non-avian Dinosaur yet known from North America. The diminutive Hesperorynchus was only about as large as a small Chicken (4lbs [1.8kg]) and lived in present-day Alberta. While fossilized eggs of this animal have never been found, fossil traces of related species can be used to approximate its eggs and nest. Hesperorynchus and its relatives had eggs that were only about 1/2 as large as birds of similar sizes. A small Chicken, such as a Silky hen, might lay an egg with a volume of about two cubic inches (33cm3). To build the replica, a proposed Hesperorynchus egg with a volume of one cubic inch (16cm3) was first rendered with 3D drawing software, then turned on a wood lathe by hand. A silicone rubber mold was made from the turned egg, then used to cast additional replicas in epoxy resin. The next photograph shows the whole clutch of replica eggs from the mold. The single finished egg at lower left was sanded smooth, then painted with a faint green enamel paint. Fossil evidence indicates that some dinosaur eggs were pigmented in green and other other colors.


Thanks for reading! This post provides a general description for this project and its underlying scientific and design concepts. We'll post updates as the planting takes hold and grows in to complete the ancient world living display.