Shells for ID

[goosey]

I thought these two were quite pretty and distictive and would be easy enough to ID, but I have been looking and they aren't .

1. Seaweed had totally fused the shell, it is that you can see it stuck to the edge of it.

1.


2.This marbled shell had a distictive serrated edge.

2.

[Pudding4brains]

Hi Goosey,

Of course I dunno shells, but maybe have a look at Zirfaea crispata and Donax (vittatus?)

Cheers, Arp

[goosey]

Originally Posted by Pudding4brains

Hi Goosey,

Of course I dunno shells, but maybe have a look at Zirfaea crispata and Donax (vittatus?)

Cheers, Arp

You're a dark horse! Fancy knowing shells even when you say you don't, and you must live almost as far as it is possible to be away from the coast over in the East of the country!

You are spot on with the Zirfaea crispata.

Although I can't see any visual examples like the other one I found Donax vittatus written description sounds good for it. Black could know?

Thanks Arp

[Pudding4brains]

I would suspect the black streaks to be (scars of old?) damage or so

(I grew up in Oegstgeest at about a 30 minute bike ride from the beach, but wasn't much into IDing wildlife then )

Cheers, Arp

[black]

Yes Goosey, the second marbled shell looks like a Banded Wedge Shell Donax vittatus. The seratted edge has a fancy name of marginal crenulations.

Staining of shells is quite interesting
Anaerobic bacteria living in anoxic sediments produce hydrogen sulphide that can interact with iron in the sediment producing iron sulphides that blacken sea shells. This blackening only usually occurs on the shell surface. If more oxidising conditions and iron is present - leading to the formation of ferric oxides then shells can be stained orange. Pink or red pigments can occur in some shells such as oysters depending on what the 'shell' was feeding on.

[goosey]

Originally Posted by black

Yes Goosey, the second marbled shell looks like a Banded Wedge Shell Donax vittatus. The seratted edge has a fancy name of marginal crenulations.

Staining of shells is quite interesting
Anaerobic bacteria living in anoxic sediments produce hydrogen sulphide that can interact with iron in the sediment producing iron sulphides that blacken sea shells. This blackening only usually occurs on the shell surface. If more oxidising conditions and iron is present - leading to the formation of ferric oxides then shells can be stained orange. Pink or red pigments can occur in some shells such as oysters depending on what the 'shell' was feeding on.

That is an interesting thought. I will keep an eye out for more blackening shells and other stained shells .
Fancy shells having crenulations and I thought it was just castles .

[goosey]

Originally Posted by black

Yes Goosey, the second marbled shell looks like a Banded Wedge Shell Donax vittatus. The seratted edge has a fancy name of marginal crenulations.

Staining of shells is quite interesting
Anaerobic bacteria living in anoxic sediments produce hydrogen sulphide that can interact with iron in the sediment producing iron sulphides that blacken sea shells. This blackening only usually occurs on the shell surface. If more oxidising conditions and iron is present - leading to the formation of ferric oxides then shells can be stained orange. Pink or red pigments can occur in some shells such as oysters depending on what the 'shell' was feeding on.

It looks as if Donax vittatusis could be prone to staining, I found another one yesterday which was stained. But that is a bit of a wild statement seeing as I have only ever come across two stained shells, not the sort of evidence to base a thesis on .

The other shell in the image, also Donax vittatusis is void of all staining and very pretty, though it has been attacked, bored into by a Necklace Shell -Euspira catena and predated if the hole is full thickness (I didn't check )

[Pudding4brains]

Interesting stuff about the predation. I had no idea - thanks

[goosey]

Originally Posted by goosey

2.This marbled shell had a distictive serrated edge.

2.

Originally Posted by black

Yes Goosey, the second marbled shell looks like a Banded Wedge Shell Donax vittatus. The seratted edge has a fancy name of marginal crenulations.

Staining of shells is quite interesting
Anaerobic bacteria living in anoxic sediments produce hydrogen sulphide that can interact with iron in the sediment producing iron sulphides that blacken sea shells. This blackening only usually occurs on the shell surface. If more oxidising conditions and iron is present - leading to the formation of ferric oxides then shells can be stained orange. Pink or red pigments can occur in some shells such as oysters depending on what the 'shell' was feeding on.

It has been a while but earlier this week I came across another stained shell, this time not a Banded Wedge Shell.
I don't know that the shell is but the staining is a lot browner this time.
This new shell also has a yellow hue like the Banded wedge shells, do you think staining occurs more often in yellow shells?




An Id would be great if anyone can help out?
Thanks.

[chris butterworth]

The shell is Tapes decussatus Chequered Carpet Shell, probably the commonest of the Venus Shells. The rather 'square' shape, the fine radiating lines becoming coarser at the ends and, on the first photo, a few brown zigzags at the right hand end near the margin are the best ID features. I think the staining shows up better on yellowish shells, mainly 'clams' because they tend to burrow deeper than cockles and can be in contact with anerobic muds.

Chris

[goosey]

Originally Posted by chris butterworth

The shell is Tapes decussatus Chequered Carpet Shell, probably the commonest of the Venus Shells. The rather 'square' shape, the fine radiating lines becoming coarser at the ends and, on the first photo, a few brown zigzags at the right hand end near the margin are the best ID features. I think the staining shows up better on yellowish shells, mainly 'clams' because they tend to burrow deeper than cockles and can be in contact with anerobic muds.

Chris

Thanks Chris, now to look out for some staining on non yellow shells!

[Pudding4brains]

Howdy,

Maybe interesting as the predation issue popped up earlier. In the 2nd issue of Kijk op Exoten (sept. 2012) a fairly new fierce predator named Rapana venosa is mentioned.

Cheers, Arp