Dinosaurs and Sex ?

This year 2022 appears to be a record breaking one for dinosaur discoveries. 

A 10 metre skeleton found in Rutland, UK; a new species of dinosaur, with disproportionately short arms like those of Tyrannosaurus rex, discovered in Argentina; another similar one unearthed in Egypt and pregnant ichthyosaur fossils with intact embryos discovered from the Tyndall Glacier in Chile’s Patagonia region.

Sex – how?

This question has kept scientists puzzled for ages. The remains have been skeletal until a recent find was made of their soft tissue and genitalia. The news seems engrossed with dinosaurs having sex!  Imagine these heavyweights, often with huge muscular tails, razor sharp fins and teeth trying to have it off. They had to do it somehow.

The Messel Pit in Germany, is the richest site in the world, providing unique information about the early stages of the evolution of mammals.  It includes exceptionally well-preserved mammal fossils, ranging from fully articulated skeletons to the contents of stomachs of animals.

An amusing and factual article by Zaria Gorvett from BBC Future on discovering how the giants of yesteryear – aka the dinosaurs did it.  Jakob Vinther at the University of Bristol, UK, describes a remarkable find in the fossil record. A psittacosaurus, literally “parrot-lizard”. This sweet little beaked herbivore and close relative of the triceratops has revealed its bottom!  And the scientists rejoice.

The psittacosaurus potters over to the water’s edge on two feet – she stopped walking on all fours as she got older – but then tragedy strikes. Just as she’s leaning down for a sip with her parrot-like beak, she slips, falls in and drowns. As she plunges to the bottom of the lake, she ends up inelegantly splayed on her back  – accidentally preserving her genitals for future apes to wonder over.

BBC.com/future – Zaria Gorvett

Prefer to watch and listen? BBC also posted on Youtube a short video of how they may have done this – this way or that way, but definitely carefully. 

And not to be outdone, Sir David Attenborough’s new show Prehistoric Planet also delves into this unexplained mystery.  

Scientists have discovered plenty of other interesting facts about these prehistoric animals.  There was even one spiky, heavily armoured herbivore, Nodosaur, that was Ginger!

Dinosaurs

Dinosaurs were a diverse set of reptiles that existed some 245 million years ago.  Estimates vary, but in terms of extinct non-avian dinosaurs, about 300 valid genera and roughly 700 valid species have been discovered and named. The most iconic of all is the terrifying Tyrannosaurus Rex. However recent studies published in 2020 and 2021 show that these large dinosaurs shouldered out their carnivorous competition by changing dramatically as they aged. While young tyrannosaurs were lithe and only capable of hunting small prey, a teenage growth spurt turned the meat-eaters into huge, bone crushing predators.

Dinosaurs can be classified into various groups of which there are seven major ones.  The most basic subdivision of dinosaurs is based on their hips. This was proposed by Harry Sheely in 1888 but has subsequently been challenged. 

Non-avian dinosaurs (all dinosaurs besides birds), which are now extinct, varied greatly in shape and size. Some weighed as much as 80 tons and were more than 120 feet long. Others were the size of a chicken and weighed as little as 8 pounds. They all lived on land. Some may have gone into the swamps and lakes for food, but they did not live entirely in water. Meat-eaters walked on two legs and hunted alone or in groups. Plant-eaters walked on either two or four legs and grazed on plants.

During the Triassic, and for most of the Jurassic, atmospheric concentrations of carbon dioxide were high and caused intense temperatures. There is no evidence of polar ice caps then, and excavations have shown that deciduous forests grew in polar regions. At the end of the Triassic, a geologically brief period of perhaps a million years saw the extinction of more than three quarters of all terrestrial and marine species on the planet, including shelled creatures, corals and all sizeable reptiles.

A new study turns the idea of heat-loving dinosaurs on its head.  Evidence has found that the minor group of Triassic dinosaur species were relegated to the polar regions.  Here they adapted to the cold, thereby surviving when the earth got cold. There is also evidence that most dinosaurs had primitive feathers, if not for flight or mating but as insulation.

In contrast to the conventional imagery of dinosaurs always living in lush tropical jungles, this new research shows that the higher latitudes would have been freezing and even covered in ice during parts of the year.  Dinosaurs living at high latitudes just so happened to already have winter coats [while] many of their Triassic competitors died out, according to Stephen Brusatte, professor of palaeontology and evolution at the University of Edinburgh.