Hello everybody! Glad to have some more stuff to post; it's been a while since I've had the time to work on the wee beastie.
This episode features the hands and arms (again) as I refine the shapes of some of the bones and do a bit more assembly. The bones are being bulked out by single layers of paper towel rolled and pressed into shape and soaked with diluted white glue. This is also used to form the third metacarpal, the small, slightly curved tapering rod attached to the outside of digit II's metacarpal. This has sometimes been called T.rex's "pinky finger" but it is not thought to have been a functional digit as it has no joint surfaces for further phalanges. It was most likely buried in the flesh of the hand, a vestige of the ancestral three fingered condition seen in more ancient tyrannosauroids
The first skeletal reconstructions of T.rex featured three fingered hands, but this was speculation. This three fingered hand can be seen in the first scientific papers by Henry Osborn (see http://digitallibrary.amnh.org/dspace/handle/2246/1464 and http://digitallibrary.amnh.org/dspace/handle/2246/1473) and in the original mounting of the American Museum of Natural History specimen #5027(AMNH5027 see http://www.lindahall.org/events_exhi...b1916b_l.shtml).The discovery and description of Gorgosaurus libratus revealed the didactyl nature of the tyrannosaur manus (see http://www.palaeos.com/Vertebrates/U...a/340.760.html). Hands from T.rex itself weren't found until the early 1990's with the discovery of Museum of the Rockies specimen #555 (MOR555) and Sue. The third metacarpal eluded paleontologists for longer still. Here's an example from a Black Hills Institute specimen called Wyrex:http://www.unearthingtrex.com/media/prep06_arms-hands/
The carpal bones (two little brown specks between the hand and forearm bones) are made from a coloured foam sheet. I picked up the brown "Foamies" sheet at a local art supply store (a tip of the hat to the friendly, helpful and courteous staff at Mercury Art & Crafts Supershop for their assistance) to use for the intervertebral discs but decided it might work for these little scraps of bone too. Foamies come in a wide variety of colours. I can't help but think I might find other uses for them yet. The carpals on my model help conceal the twisted wire used to connect the hand to the ulna and, being flexible, will probably handle the movements at the wrist without coming off or breaking as a harder material might.
The elbow joint is one of my hinges made of thinner cardboard with a section of round toothpick for the pin; the shoulder joint is twisted wire covered in a mixture of glue and paint. I probably won't attach the arms to the scapulocoracoids until the latter are mounted to the completed ribcage, so it's going to be a while yet.
A quick comparison with one of my references lets me tell how things are coming along. Verdict-looking good!
After some final work on shaping and priming the forelimbs I will probably turn to toes to fill and shape them before working out the mechanics of the leg and hip joints.