Down t'pit

Posted by Graeme Lyons , Sunday 4 July 2021 09:57

Rained off again yesterday and most of today it would seem. Frustrating how quickly you can get behind after being ahead. But an opportunity to do some spider recording it was (they are less effected by weather than a lot of other taxa and if you pick the right habitat, the problems of wet vegetation that stop a full survey can be minimised). So I got in touch with Amberley Museum and got access to a few areas of Amberley Chalk Pit. I had two targets in mind; Iberina candida and Eratigena picta. I failed to find both (well, I might have an immature of the latter) but I don't care. I found something even rarer. But first, the supporting cast...

Almost the first rock I turned over had a Zodarion retreat underneath it! Never actually seen this before so was pretty pleased. I found two females of what is Zodarion italicum. I have records for this at Shoreham Beach but they are not in my database for some reason, other than that this is only the second West Sussex record.

A real surprise for me was this stunning Xerolycosa nemoralis. I have only ever seen this on bare sandy ground on heaths. Its nationally scarce and a new 10 km square record. It just shows that spiders will use any structural type that is analogous to what they need. The soil here is exposed and friable, a successional state of old quarries that is quite uncommon. Many are vegetated over, mossy or with a tight sward. Not so here.

Moving to the scree generated some excitement. I spent an hour trying to catch an adult of what I thought was going to be Eratigena picta. It was Tegenaria silvestris. Bugger. A clearly very different looking spider but in the heat of the moment, I was rather excited. It was still new for the year, however!

Scree is hard to work. My suction sampler was useless here. All I had was my hands. I found Hahnia nava and montana but no Iberina candida either. I did see plenty of Palliduphantes pallidus.

And found some nice adult Mitostoma chrysomelas

And a huge golden yellow liny that escaped me. Only to resurface some 30 minutes later. I am extremely persistent. It was Saaristoa abnormis. Only the second time I have seen it and my first male/Sussex specimen and a new 10 km square.

Rosy Woodlouse was extremely common under stones there.

And who needs pheromones when you have a suction sampler? Six-belted Clearwing sucked off the chalk!

Walking around the old buildings in the Museum, the UK's biggest jumping spider, Marpissa muscosa, caught my eye.

But it wasn't until I got home and looked at the specimens that things got really exciting. A little yellow thing about 1.5 mm (that I have to say, I have no memory of collecting) jumped out immediately as a Centromerus when I clocked the epigyne, and not one I recognised either. I just wanted to completely rule out Centromerus serratus, so asked Tylan for a second opinion and he kindly sent me a photo of an epigyne and I was happy to rule it out then (he sees that more than me and I don't have a specimen of the female). It was Centromerus albidus! Critically Rare, Nationally Rare and get this...not seen in the UK since 1969!!! So this made up for not finding the targets as this is significantly rarer and totally unexpected. It's also new to Sussex and you can find out more on the SRS page here

The page mentions Beech woods, so this is a totally different habitat to the old sites.

I got seven new spiders for the year, ending on 312 (including Tetragnatha obtusa and only my second ever Troxochrus scabriculus - EDIT, it wasn't Troxochrus. it was Entelecara flavipes). Here is a list of the species seen that had conservation status.

Centromerus albidus - NR/CR
Drassyllus lutetianus - NS
Marpissa muscosa - NS
Zodarion italicum - NS
Xerolycosa nemoralis - NS
Entelecara flavipes - NS

Six-belted Clearwing - Nb
Orthochaetes setiger - Nb

It was very kind of the Museum to let me access this fantastic site. It's not a public access site though, and is dangerous without a brief, so please don't go there without talking to the Museum. One thing I am sure of, there is more to be found at this amazing site and I will be back.

So what better way to celebrate than with some Mouse Rat?

1 Response to "Down t'pit"

Gibster Says:

Fantastic! Not sure if I'm more surprised that you turned up a spider that hasn't been seen for over 50 years, or that you called a baked bean on stilts "nice"!!

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