Brachiopod from Blue Nile Gorge

[2Ronalds]

In 2005 I bought five shells from a kid when we made a trip from Addis Abeba to the Blue Nile Gorge. As I started to collect fossils I realise the shells must be brachiopods. I never see pictures from brachiopods from Ethiopia, so it is even more difficult to identify them than usual. The boy hardly spoke English, and I doubt if he knew the geologic formation they came from. I now found an article that says there is one fossil-rich limestone layer dating late oxfordian/early kimmeridgian (so in the middle of the late jurassic). It is certainly a Rhynchonellid, but which one?

[Editted by 2Ronalds on 06-09-2011 at 00:03 GMT +1]

[FossilDude]

Hey,

Yeah, you don't come across fossils from Ethiopia that often! Which is actually a pity.
I am not a brachiopod expert, so I find it hard to give you a name (other than: Rhynchonellid, yes). I guess the article you wrote about is the Kiessling et al., 2011 paper?

Interestingly, there are some Ethiopian post stamps out there with (Cretaceous?) brachiopods on them (see pics). These are Rhynchonella abyssinica respectively Rhynchonella subulata . So I guess that there might be Cretaceous fossil bearing deposits there as well.

Sorry for not being able to help you out here! Good luck with it!
Cheers,
Johan

[Bewerkt door FossilDude op 06-09-2011 om 09:57 NL]

[2Ronalds]

Thank you so much Johan! I now read the Kiessling et al. paper carefully and I am positive the pictures show Somalirhynchia africana. I also identified two other species, but I guess now I know their names I must post the pictures in another box.

[Editted by 2Ronalds on 07-09-2011 at 01:08 GMT +1]

[Editted by 2Ronalds on 07-09-2011 at 14:05 GMT +1]

[FossilDude]

That's great!

Cheers,
Johan

[Frederik]

I have found a rynchonellid in Tigray when I was there in 2004. I'll take a picture.
Did you purchase the specimens at a blue nile gorge touristic hotspot or at a more remote location? In the latter case, it is very likely that the fossils were found in close proximity of the spot you found them.

Picture in attach: fresh water snail in quarz, ET.

[2Ronalds]

Thanks Frederik,
I did buy the specimens at the Blue Nile gorge at a remote location. A cab brought me to the gorge over the asphalt road that had recently been constructed. Where it arrived at the gorge it turned into a durt road. The driver didn't want to go on. There was nothing at that point, except for four school-aged boys, one of them selling the fossils.

I've added three pictures of a specimen that bought from the same boy, thinking it was just another (bivalve) shell. However now that I started collecting and know a bit more, I had another look at it and have admit I have no clue to what it could be. I'm sure it is no bivalve or brachiopod.

I guess it must be from the same deposit as the Somalirhynchia africana, the Monsardithyris and the Amydroptychus (see locations forum) as the mineral of the fossils are identical and so is the matrix limestone. Hence late Oxfordian to early Kimmeridgian.

The specimen has an overall shape strongly reminescent of the shell of a pistachia nut. Its dimensions are 25mm x 14mm x 15mm, in cross section rectangular with four blunt edges, flattening near each end, but at a different angle (roughly 30 degrees). At one end possibly the tip is missing, but the ridges seem to fan out and touch eachother, suggesting a large opening at that side. large parts have a pattern of fine (.3mm) parallel ridges, but there are other parts where the shell has much broader bands (.5mm) of thicker material and narrower thinner material and the direction of these bands are at an angle with the ridges in the neighbouring parts.

[Editted by 2Ronalds on 11-09-2011 at 14:47 GMT +1]

[Editted by 2Ronalds on 11-09-2011 at 14:48 GMT +1]

[Editted by 2Ronalds on 11-09-2011 at 16:03 GMT +1]

[2Ronalds]

I have now figured out the identity of the fossil in my message just above. It is Musculus somaliensis, a member of the Mussel Family. It occurs in the same strata as the Brachiopods Somalirhynchia africana, Amydroptychus sp. and Monsardithyris sp.

[Frederik]

Nice of you to share your findings here too. It's a bivalve after all.

[Juergen]

Hi, for me your brachiopod does not look like a Somalirhynchia africana which is a little bit trilobate and has a rounded uniplication. It looks more like the Middle Jurassic Sphenorhynchia plicatella. Cheers, Juergen