At an estimated age of more than 150 years, Speed had been in geriatric decline for some time, with arthritis and other maladies. Keepers treated him with medication, hydrotherapy, physical therapy, even acupuncture.

Finally, a decision was made Friday to euthanize Speed, who had been at the zoo since 1933.

He was brought to the zoo as part of an early effort to preserve the endangered species from the Volcan Cerro Azul Island of the Galapagos Islands, off Ecuador.

At a conference on Bahamian natural history, I met Shedd Aquarium’s Dr. Chuck Knapp, who oversees the conservation research program at Shedd and has spent decades researching rock iguanas in The Bahamas. At the time, I had been struggling with the decision of attending medical school. Would I make a difference working in a ‘normal career’, as in a sterile hospital wearing a white lab coat, be any different than working as a field researcher?

For me, Dr. Chuck helped to provide that answer. Without thinking twice, I accepted his invitation to accompany him on a citizen science iguana research exhibition to the Exuma Cays. My experience on that expedition–adjusting to the harsh weather and elements – proved to me that the white lab coat in some hospital was not going to be my career path. I found an unexplainable love for field research and the Exuma Cays Rock Iguana (Cyclura cychlura figgisi), in an experience that I will never forget.

The findings are “a very important contribution in addressing who turtles are related to, as well as the evolutionary origin of the turtle shell,” says Tyler Lyson, a vertebrate paleontologist at the Denver Museum of Nature & Science who was not involved with the study. “These have been two vexing questions for evolutionary biologists for the last 200 years.”

About two dozen or so fossils of the creature have been recovered, all of them from 240-million-year-old rocks deposited as sediment on the floor of a shallow, 5-kilometer-long lake in what is now southern Germany. Most of the remains include only bits of bone and are from individuals of various sizes, says Hans-Dieter Sues, a vertebrate paleontologist at the Smithsonian Institution's National Museum of Natural History in Washington, D.C. But between the two most complete specimens yet found, he and Rainer Schoch, a paleontologist at the State Museum of Natural History Stuttgart in Germany, have put together a full skeleton and most of a skull.

John Meek, curator: " This is a very rare birth for us here at The Zoo and Mez is doing very well, being carefully nursed by our diligent keepers. Mez currently weighs twelve grams and we expect him to make steady progress."

Black Tree Monitors are at risk due to habitat destruction and the illegal trade in reptiles for pets, so the breeding programme at The Zoo will ensure the conservation of the species.

The Black Tree Monitors at The Zoo originated from Pilsen Zoo in the Czech Republic over five years ago and have very specific humidity conditions to encourage them to lay their eggs. The female Monitor has already laid a further six eggs which are currently under incubation and they should hatch sometime in the next few months.

Owner Stephen Evans, 34 has bred bearded dragon lizards for 17 years and made the discovery this morning after checking a clutch of eggs.

Originally, he thought there were two lizards in one egg but says he was shocked to discover it was actually a conjoined twin.

He told the Liverpool Echo: "Last night I'd checked the incubator, we'd seen two heads and assumed they were twins, which can sometimes happen.