Mission Tylos punctatus

@finatic & @jaykeller, I sadly dipped on my hunt for Tylos punctatus during my 2 hour nature window during yesterday's one day work visit to San Diego.

These are very cool native endangered Oniscideans (woodlice/rollypollys) that barely make it into the US along SoCal beaches north to Capistrano Beach. The crazy thing is since these beaches are so developed they're barely hanging on. This paper describes a study that resurveyed Tylos and another native declining Oniscidean with similar habits Alloniscus perconvexus that ranges up to the Bay Area where I've found it a few times.

On Fig 2a of the paper it looked like Silver Strand Beach to the south and Torrey Pines to the north of San Diego are the last places nearby to see Tylos. I went to Silver Strand because it was nearer, but a more careful read shows that there's actually just one surviving population in the whole 'Silver Strand cell'. I talked to the authors and they confirmed that Torrey Pines is a more reliable place to find these guys (and has the added bonus of also having Alloniscus perconvexus).

Your mission, if you choose to accept it, is to avenge my tragic dip and tick Tylos punctatus in San Diego county on iNat. Sections 2.2 & 2.4 of the paper describe how to find these guys during the day (digging down under wracks ~20cm along the high tide line and looking for a pillbug about the size of your last pinky joint - I can confirm this works for Alloniscus). At night, according to Jonathan Wright who studies these:

"I haven't searched for Tylos in the San Diego area, but they should be common there. Any quieter sandy beach would be good habitat. Torrey Pines State Beach looks promising. Just scan the debris along the strand line from the previous high tide after sundown; I've usually found them when it's completely dark - 1-2h after sunset - and they should be active most of the night. Depending on the beach, you may find Alloniscus much commoner than Tylos or vice versa. I've not been able to differentiate their specific habitat requirements, though they are usually found together. Both are beautiful animals! I've found Tylos in the highest densities at Malibu Beach, though this is near their northern limit, so I suspect the San Diego area might be even better. I do worry, however, about the increasing use of SUVs to patrol beaches and the impact this may have on the populations of both these species. I've not found them in a long stretch of Huntington Beach where such traffic is heavy."

If you guys are successful, I'll commit to a similar Bay Area mission of your choosing...

Happy hunting,

Scott

Posted by loarie loarie, October 15, 2015 16:09

Observations

Photos / Sounds

Square

What

Giant Kelp Macrocystis pyrifera

Observer

loarie

Date

October 14, 2015 10:30 AM PDT

Description

Looking for Tylos punctatus following this pub to Silver Strand State Beach but sadly came up short. They apparently hang out under wracks of giant kelp buried ~20cm in the sand. Next time I'll go to Torrey Pines where I bet theres a better shot at finding them

Comments

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Mission accepted!
Too bad you weren't able to find them while you were here. And sadly we weren't able to connect during the brief time you had. Hopefully again in the near future we'll be bale to get out paths to cross.
I am surprised they they aren't found on Imperial Beach as this is the least traversed stretch of beach in the county, and the furthest south.

Posted by finatic almost 4 years ago (Flag)
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Excellent!! yes, unfortunate timing on my visit, but inspired me to come down just for fun in the future. That is interesting re: Imperial Beach, Fig 1 of the paper shows extirpations there, and Fig 2 doesn't show a circle there so I assume that means the study didn't find them there.

Posted by loarie almost 4 years ago (Flag)
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Strange trends. The beaches with the most limited disturbance are the ones with presumed extirpation. Torrey Pines is actually fairly heavily trafficked by beachgoers and vehicles (life guards and state parks). I have a few little places in mind where I can check some evening when I get tired of working on photos.

Posted by jaykeller almost 4 years ago (Flag)
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yes - I thought they were blaming beach raking on the decline, but Silver Strand State Beach where I visited was unraked still I think they've disappeared from at least the State Beach portion of whatever the 'Silver Strand Cell' is. Granted there were no dunes behind the beach (only parkinglot/Hwy). I wanted to explore the bit to the north of the State Beach where there were dunes but thats closed for the military, and probably has its own 'vehicle problems'

Posted by loarie almost 4 years ago (Flag)
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We'll find them. :-)

Posted by jaykeller almost 4 years ago (Flag)
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Wish wish wish I could come and go rolypoly hunting with you guys...

Posted by sambiology almost 4 years ago (Flag)
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Please post updates here if you're successful in your quest! :-)

Posted by carrieseltzer almost 4 years ago (Flag)
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I checked the Tijuana River Mouth area on Saturday night with the off chance that they may still be present at that location, but did not find any. Will keep looking...

Posted by jaykeller almost 4 years ago (Flag)
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nice - thanks. keep your eye out for sea-snakes too!

Posted by loarie almost 4 years ago (Flag)
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Oh, I have been hoping!

Posted by jaykeller almost 4 years ago (Flag)
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*envy* ;)

Posted by sambiology almost 4 years ago (Flag)
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@sambiology @loarie @carrieseltzer Come on out this weekend and help us look. I want to go looking for Leopard Sharks (and maybe a sea snake) in the morning then head out looking for this special Tylos. I'm hoping to talk @jaykeller into joining.

Posted by finatic almost 4 years ago (Flag)
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*starting to walk over to California now...*

Alas, I'll be at a Master Naturalist conference in Marble Falls, TX -- I'm giving a presentation on iNaturalist and spacial accuracy of observations!! :)

But please, oh please, post EVERYTHING -- that way I can truly live vicariously through your adventures. :)

Posted by sambiology almost 4 years ago (Flag)
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Sam, I've been been accused of not posting enough. LOL.

Posted by finatic almost 4 years ago (Flag)
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I'm not attempting these things during the day. Who wants to dig down a meter into the hard packed sand? I doubt you do...

Posted by jaykeller almost 4 years ago (Flag)
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in the paper they just dug 20cm which is pretty shallow. When I've found Alloniscus in the past its literally just taking a handful of sand from the surface

Posted by loarie almost 4 years ago (Flag)
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All over it, I will be in San Diego next week. I should bring my 8 year old , she loves digging in the sand and looking through seaweed with me.
BTW I like Pale ale

Posted by tiyumq over 2 years ago (Flag)
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I've kept these in mind and searched when able, but so far nothing. I guess not easy critters to find, or I am just not looking correctly.

Posted by jaykeller over 2 years ago (Flag)
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I, too, have kept this is mind. I think a night outing to the beach might be needed. No luck so far during the day,

Posted by finatic over 2 years ago (Flag)
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Posted by loarie about 2 years ago (Flag)

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