Pronunciation: tih-MIEM-us
Meaning: Tim's mimic
Author/s: Rich and Vickers-Rich (1993)
Synonyms: None known
First Discovery: Victoria, Australia
Discovery Chart Position: #380
Timimus hermani
Australia seems to be the world leader in dinosaurs that are represented by a single and unusually slender limb bone, so it comes as little surprise that Timimus, found at Dinosaur Cove in Victoria, is represented by a single and unusually slender limb bone.
A femur (thigh bone)—43 centimetres long—was originally thought to be the property of an ornithomimid, which would confirm the presence of "bird mimics" in the Southern Hemisphere and, based on the age of the Eumeralla Formation where it was found, suggest a possible Southern Hemisphere origin for that entire family. The problem is that derived ornithomimid traits in its scant remains are sadly lacking, and it seems likely that Timimus is an unenlagiine deinonychosaur. That said, dinosaur thighs are far from the most helpful bones for diagnostics, and a basal tyrannosauroid theory is building up a head of steam as we speak.
Whatever Timimus may turn out to be, cross-sections of its bone revealed lines of arrested growth (LAGs)—dark bands, like growth rings in trees—which are formed by a drastic drop in metabolism, perhaps due to a lack of food and water, or environmental stress. Some palaeontologists think the cause may have been a combination of all three and are interpreting these LAGs as evidence that Timimus hibernated to escape the unforgiving polar winters.
A femur (thigh bone)—43 centimetres long—was originally thought to be the property of an ornithomimid, which would confirm the presence of "bird mimics" in the Southern Hemisphere and, based on the age of the Eumeralla Formation where it was found, suggest a possible Southern Hemisphere origin for that entire family. The problem is that derived ornithomimid traits in its scant remains are sadly lacking, and it seems likely that Timimus is an unenlagiine deinonychosaur. That said, dinosaur thighs are far from the most helpful bones for diagnostics, and a basal tyrannosauroid theory is building up a head of steam as we speak.
Whatever Timimus may turn out to be, cross-sections of its bone revealed lines of arrested growth (LAGs)—dark bands, like growth rings in trees—which are formed by a drastic drop in metabolism, perhaps due to a lack of food and water, or environmental stress. Some palaeontologists think the cause may have been a combination of all three and are interpreting these LAGs as evidence that Timimus hibernated to escape the unforgiving polar winters.
Etymology
Timimus is derived from "Tim" (for two Tims: Tim Flannery, and Tim Rich, the son of Tom Rich and Patricia Vickers-Rich) and the Latin mimos (mimic). By the way, the authors weren't suggesting that Timimus was mimicking the Tims, they thought it was a member of Ornithomimosauriaâ: the bird mimics.
The species epithet, hermani, honours John Herman, a volunteer who assisted at the Dinosaur Cove project for many a year.
Discovery
The only remains of Timimus were discovered at "Lake Copco" quarry in the Eumeralla Formation at Dinosaur Cove, Victoria, Australia, in 1991. The holotype (P186303) is a femur, 43 centimetres long. An even smaller, more slender femur (NMV P186323) was discovered less than a meter away from the first, and may belong to a juvenile specimen of Timimus.
