[ID] Opilione

Fauna · #1 (**permalink**) 18-02-2011, 05:27 PM

Could someone point me right for this one please...

Found dead in a plant pot on a colliery spoil. Not the best of pics, but i should be able to get better tomorrow if needs be... I was thinking along the lines of Dicranopalpus ramosus? but im no good with Opiliones.

The body was 4mm.

This one was taken down the microscope.

Regards Chris...

Fauna · #2 (**permalink**) 18-02-2011, 06:18 PM

Scrap my original thought of Dicranopalpus ramosus...Is this Rilaena triangularis?

Regards Chris...

Geoff F · #3 (**permalink**) 18-02-2011, 06:41 PM

Well, Chris, my first thoughts based chiefly on overall appearance was Phalangium opilio but those pedipalps certainly look like Rilaena triangularis.

Any idea of leg length, particularly the second legs?

Fauna · #4 (**permalink**) 18-02-2011, 08:29 PM

Hi Geoff...

Your in luck, the second legs seem to be the only ones that are not damaged.

They where about 8mm, deffinetly no more than 8.5mm.

Regards Chris...

Geoff F · #5 (**permalink**) 19-02-2011, 07:38 PM

If you are certain about those leg lengths, Chris, this is a specimen which requires Gordon's expertise.

R. triangularis second leg lengths are normally 28 mm or longer.

The only species which I can think of that has similar shaped pedipalps and short legs is Lophopilio palpinalis. Second legs are usually around 12 mm or slightly longer.

But the general appearance doesn't seem to quite match my book; this is a species which I have yet to encounter.

It has a rather prominent slightly forward pointing trident on it's 'nose'. Those photos aren't sufficiently clear in that area.

However, you could have a look at that species while waiting for Gordon to come along.

Fauna · #6 (**permalink**) 20-02-2011, 07:53 PM

Cheers Geoff for your time on this...

I just double checked the legs just incase they where snapped off at the ends, there is a claw showing at the tips...8mm looks to be right.

There are no "spines" on the "nose", the tops of eyes do have small black "spines".

I have checked all UK species against many photos ect, the nearest i could find is a similar looking specimen on Fotogalerie Arachnida ....It has been labeled cf. Rilaena, if you go to A-Z it is under Rilaena, the bottom most photo.

I'm off to the Museum tomorrow to get some ids on various species, i will take this along as well.

Regards Chris...

Geoff F · #7 (**permalink**) 20-02-2011, 08:06 PM

This is certainly an interesting specimen so if you get a result please post the answer.

Incidentally, Gordon's identification site is here http://sites.google.com/site/opilion.../home/logo.png

And if you get really interested in Opiliones I would recommend a copy of Harvestmen by P. D. Hillyard from the Field Studies Council. I can't remember the price but it isn't overly expensive for what has become one of the recognised authorities.

Fauna · #8 (**permalink**) 22-02-2011, 10:52 AM

Cheers Geoff for the link etc, i've got Gordons site bookmarked.

I have handed the specimen over, there was no one about to take a look at it on the day. The specimen is fairly battered but i'm sure there is still enough features there for identification. Will post details as soon as i recieve...

Regards Chris.

Fauna · #9 (**permalink**) 06-03-2011, 02:05 PM

The specimen was identified as Rilaena triangularis, but no other info. I wonder if it was a juv?

Regards Chris...

Geoff F · #10 (**permalink**) 06-03-2011, 07:20 PM

Thanks for the confirmation; it's always gratifying to hear of a success.

At that size and time of the year I would say it was an adult.

This species is one of the earlier season harvestmen and usually die off towards the end of the year. Eggs hatch during late autumn and the tiny juveniles spend the winter hiding amongst leaf litter etc.