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Home > True Science > Pretty Spectacular Dinosaur

Pretty. Spectacular. Dinosaur! by Bob Simon (c)2017

During the 2008 digging season, we found and excavated a juvenile Sauropod dinosaur. Based on the teeth, images of which were shown to Sauropod specialists, the ID is Apatosaurus. Field nickname: Junior.

The dinosaur was found partially articulated, with some of the skeletal elements not in “living position.” Luckily, it was Junior’s state of rest that helped preserve the most precious part, the skull. Here’s the story: 

The 2008 dig season at our Late Jurassic, Morrison Formation dig site in northcentral Wyoming began with some major trackhoe work to remove overburden. The first week of continuous digging and overburden removal was rewarded when a Sauropod femur was found. Unsure whether this was just an isolated bone, we continued excavating very carefully, encountering other bones nearby in the same strata.

Careful hand-digging. Over the next three weeks revealed that we had something very exciting – a relatively complete juvenile or small Sauropod dinosaur. And while some of the skeletal elements were disarticulated, all bones appeared to be from the same dinosaur and concentrated in a fairly small area.

When the entire bone assemblage was exposed, it was clear this was one dinosaur. The neck was articulated and curved toward the pelvic region. The dorsal (chest) region was also articulated. The interesting positioning of the Apatosaurus showed that some of the front and back leg assemblages had flopped back over the body. In particular, one back leg was positioned such that it was on top of and protecting the skull. Many of the teeth had fallen from the jaws and were found nestled near and within the pelvic region.

So, what was the cause and effect of Junior’s final resting pose?

We believe that this dinosaur died nearby and then the carcass began to decay, possibly becoming bloated due to gases generated by decomposition. Subsequently, a flood event moved the carcass to its final resting position. Further “flesh rotting” may have contributed to increased bloating, until eventually the body exploded due to that build-up of nasty gases.

One of the front and back leg assemblages then fell on top of the body, covering the head and neck areas. Further flooding or wind-generated deposition events may have ultimately covered the dinosaur, leading to ultimate burial and preservation – with the skull preserved and still attached to the neck as it lay protected by one of the back legs. In fact, two toe tones were found embedded in the same calcareous block as the major skull elements, mildly deforming some skull parts due to their positioning. 

Apatosaurus with strataGeologically speaking. Junior the Apatosaurus was found resting on a fine-grained sandstone, evidence of a water-driven event during which the dinosaur remains were moved into final resting position. Immediately above the fine-grained sandstone layer, the skeletal remains were mostly encased in a thick, very fine-grained grey siltstone that included carbonized plant remains.

These strata are believed to be generated from lower energy flooding events or wind-blown sedimentation. To a lesser extent, some of the bones were found within very plant-rich, calcareous, and brown fine-grained layers. Pyrite was found coating some of the bones within this layer, potentially due to an original oxygen-poor, marshy environment adjacent to the river channel.

Junior today. This unprepared dinosaur appears to be approximately 80% complete or more. More associated bones could be found embedded in the thick matrix or enclosing rock that we left undisturbed around the major bones and chest cavity. Careful removal of the matrix will be done once the specimen has found a final permanent home.

At present, Junior the Apatosaurus is in storage and our goal is to deliver this scientifically valuable specimen to a museum in the near future. Meanwhile, I have been slowly working on some of the smaller, more interesting bones to show how this dinosaur will look when put on display for people to study, view, and marvel at.

More about Junior the Apatosaurus, dig site geology, and Bob Simon.


Chest and shoulder section                   Foot bones and claw                             Front & back legs

               Apatosaurus foot bones and claw Dinosaur Apatosaurus leg bonesApatosaurus ribs, scapula