Just a question about articulated/associated bones

[The Amateur Paleontologist]

Hey

 

I just had a question regarding what counts as articulated and associated bones.

 

Let's say I find the partial mandible of some crocodile. The left and right dentaries are connected as they would have been during the animal's lifetime. Would that mean that the bones are associated and articulated? Or would left and right dentaries be considered as one single bone?

 

Sorry if this is a silly question...

[Troodon]

I would say that since a skull is made up of many elements two being right and left dentaries they are both articulated and associated.  If it was two broken pieces of a right dentary then not articulated 

[The Amateur Paleontologist]

16 minutes ago, Troodon said:

I would say that since a skull is made up of many elements two being right and left dentaries they are both articulated and associated.  If it was two broken pieces of a right dentary then not articulated 

Got it, thanks. That clears things up.  

[hadrosauridae]

Articulated would mean they are fossilized as they were in life.  A series of vertebrae in it natural placement would be articulated.  A jumble of bones together would be associated.

 

[TyBoy]

In reference to your question on the jaw I view them like Troodon said.  They are of course associated but also articulated since they are a pair of the elements that make up a skull.

[caterpillar]

Articulated means there is a joint. For example between a humerus and a scapula. The crocodile dental is articulated with the quadratojugal. If we find the two bones that form the crocodile dentary (mammals have a mandible composed of a single bone, the reptiles of 2) attached together, we will speak of anatomical connection.
Two associated bones can be associated in the same deposit and not belong to the same animal
Well it's just my opinion

 

[The Amateur Paleontologist]

@hadrosauridae @caterpillar @Troodon @TyBoy Thanks for the help guys. By the way, sorry - I didn't mean to give the impression that I didn't know what articulated meant - rather, my confusion was stemming from me not remembering whether dentaries form a single bone or not. Thanks for clearing my doubts

Edited May 20, 2020 by The Amateur Paleontologist

[siteseer]

On 5/20/2020 at 6:14 AM, hadrosauridae said:

Articulated would mean they are fossilized as they were in life.  A series of vertebrae in it natural placement would be articulated.  A jumble of bones together would be associated.

 

 

It's good to spell it out because I have seen people say an isolated bone is "well articulated" when I think they meant it was well-preserved and/or had complete ends.

[Boesse]

Ooooh taphonomy questions!

 

Whether or not your mandibles are 'taphonomically' articulated very much has to do with whether or not they are fused together. I think some long-snouted croc dentaries do fuse at the mandibular symphysis (to use a mammalian term) and so if they are still fused, then it just means they are a cohesive unit - whereas two bones that have only a soft tissue connection in life that are still articulated after burial must have been buried somewhat rapidly.

 

Associated means that the bones are in close association but not necessarily in articulation, as you correctly surmised. You can have a relatively complete skeleton that is associated but disarticulated, and also relatively incomplete skeletons that may consist of a handful of bones that are still associated (e.g. a flipper separated from a floating dolphin carcass and sank to a different part of the seafloor than the rest of the carcass).

 

Here's a figure from my master's thesis publication where we used different articulation stages for specimens: