Madagascan coprolite. Actually dinosaur?

[FrostbyteFossils]

This is a small coprolite specimen from Madagascar. Just two questions:

1. Is this actually from a dinosaur or is coprolite just sold as "dinosaur" dung but in reality from any animal?

2. Due to its size surely its from a relatively small species or an infant larger species. Rahonavis too far fetched?

[FossilsAnonymous]

@GeschWhat

[Troodon]

Is there a more specific locality than just madagascar?  Not all fossil bearing localities from there are Mesozoic.  Lots of coprolite from Madagascar being sold on auction sites.   So I think you need to validate locality first.  Rahonavis is a tiny theropod this specimen would be a bit large.

[doushantuo]

Agree with Frank.

Might be a dicynodont coprolite,but Lori will certainly have ideas on this one

[Carl]

I have my doubts about these Malagasy and Washington "coprolites." I know they look the part but they fail in some very important details: they are not phosphatic (which nearly all confirmed coprolites are), they always lack biogenic inclusions (which is not a necessity but leaves these things suspicious), and at least in the case of the Washington examples, they are never found in association with any other vertebrate fossils (also, not a deal breaker, but in tandem with the other observations weakens the coprolite case). At the moment, I consider these things pseudocoprolites of some as yet unknown geological process. Yet, they are always sold as coprolites. And how could it be any other way? What would sell better: "dinosaur dung" or "geological oddity created by some as yet unknown process?"

[Fossildude19]

I took the liberty of cropping and brightening  your photo.

 

[GeschWhat]

As usual, I am in full agreement with @Carl. I would like to add that it is almost always impossible to assign a coprolite to the animal that created it. We can make educated guesses based on other fossil associated with the coprolites. For instance, if numerous large coprolites that contain bone inclusions are found near an incomplete skeleton of a dinosaur, we can hazard to guess the coprolites were left by a creature feeding on that dinosaur. We know that large animals can produce small feces, but small animals cannot produce large dung piles. While shape can play a role in identifying whether or not something is a coprolite, location and association with other fossils is perhaps the most important factor. I would also like to add that coprolites are primarily used to understand the environment in which an animal lived more so than the animal itself. It gives far more insight into the animals/plants that were consumed. 

[abyssunder]

I agree with the others, and I'll let the specialists (geologists vs. paleontologists) to decide what are the specimens from Madagascar, but if they finally will be classified as coprolites, I would believe they will be close to bromalites, something like Hirabromus igen (H. seilacheri isp).

 

" Similar ichnofossils occur in the Permian of China, and in the Cretaceous of Canada and Madagascar, and there has been a long debate as to their origin (coprolites, pseudofossils or casts of internal organs), particularly with regard to those from the late Miocene of Washington (e.g., Amstutz, 1958; Brown, 1962; Broughton et al., 1977; Broughton, 1981; Schmitz and Benda, 1991; Spencer, 1993; Mustoe, 2000; Seilacher et al., 2001). Seilacher et al. (2001) convincingly argued that these specimens are both ichnofossils and cololites (sensu Agassiz, 1833; Hunt and Lucas, 2012a) that represent fossilized sections of the gastro-intestinal tract of vertebrates. Specifically they represent evisceralites (sensu Hunt and Lucas, 2012b) which are cololites that are preserved independent of a skeleton. "

 

" Distinctive features of these bromalites that indicate that they are cololites include: (1) longitudinal striations that represent taenial muscle bands; (2) sinuous shape; (3) prominent tapering at both ends; and (4) more complex specimens (e.g., Fig. 3K-N) consist of segments whose opposing ends taper in opposite directions (Seilacher et al., 2001). "

 

excerpts from A. Hunt et al. 2012. THE BROMALITE COLLECTION AT THE NATIONAL MUSEUM OF NATURAL HISTORY (SMITHSONIAN INSTITUTION), WITH DESCRIPTIONS OF NEW ICHNOTAXA AND NOTES ON OTHER SIGNIFICANT COPROLITE COLLECTIONS. New Mexico Museum of Natural History and Science. Bulletin 57: 105-114

 

[doushantuo]

I believe geochemistry and palynology is a good way to make sure(provided diagenesis hasn't gotten in the way).

Maybe even gut microbiota.?

example:

(palynomorphs from Cretaceous coprolites)

 

[GeschWhat]

1 minute ago, doushantuo said:

I believe geochemistry and palynology is a good way to make sure(provided diagenesis hasn't gotten in the way).

Maybe even gut microbiota.?

 

I don't know too much about palynology. I'm sure it would apply with terrestrial specimens, but would it for marine specimens? I now have a good cellular microscope, so this will be something interesting to explore once I find a good way to prep specimens. 

[doushantuo]

Sporopollenin is pretty resistant,it will survive digestion..

triassic coprol

quite a long link,that one.

too large to post directly

[FrostbyteFossils]

Apologies for the late reply. Unfortunately i do not have a specific location in Madagascar. If it helps the other specimens for sale were long and thin. Kind of like thick worms. Thank you all for replying.