Crustacean pincer

[madness]

I'm pretty dang sure this is a crustacean pincer. I'm wondering if I can get any other information about it. Also whether or not it is a rare find. I've hunted fossils in Austin since I was a kid but mostly just picking up the many many oysters, brachiopods, etc that are a dime a dozen around here, with the occasional "big find" (sea urchin, etc). I've never seen anything like this, but a little research at least shows that are known to occur.

 

I found this in NW Austin, specifically in Great Hills park on the edge of a stream bed. The area is limestone. I'm finally getting around to actually learning the names of fossils/rocks/ets that I've seen my whole life. So I *think* this is Glen Rose limestone, but don't hold me to it! The limestone there is marly (new word for me!) and very clayey.

 

[Fossildude19]

Welcome to the Forum.

 

Certainly looks like a crustacean claw to me, as well.   

Lets see what some locals think.

 

@Uncle Siphuncle  @JohnJ  @erose  

[RJB]

  It appears to be the Dactyl, (movable finger) that comes off the Propodus, (hand). 

 

RB

[Uncle Siphuncle]

The Glen Rose has a hermit crab Paleopagurus banderensis which left behind some good sized claws but little else.  Compare with online images.

[abyssunder]

 

Pagurus banderensis Rathbun, 1935
(Fig. 3.3–3.6)
Pagurus banderensis Rathbun, 1935, p. 39, pl. 9, figs. 7, 8. Stenzel, 1945: 435, pl. 45, figs. 7–15; Bishop, 1983: 41, pl. 2, figs. 1–31; Schweitzer et al ., 2010, p. 56.
Palaeopagurus banderensis (Rathbun, 1935): Roberts, 1962: 175.

 

" The species has been well illustrated previously (Rathbun, 1935; Stenzel, 1945; Bishop, 1983). The right chelae in general seem to be larger than the left, so Paguridae is the best placement for the material at this time. Extant members of Pagurus exhibit a broad range of morphologies, including the thickened rim and cup-like tip on the fixed finger seen in P. banderensis. Thus, Pagurus seems a reasonable placement for the species. " - C. E. Schweitzer et al. 2016. Early Cretaceous (Albian) decapods from the Glen Rose and Walnut formations of Texas, USA. Bulletin of the Mizunami Fossil Museum, no. 42: 1–22

 

[madness]

Wow, thanks guys! Makes sense that it's a hermit crab. Trying to research fossilized crabs and lobsters kept turning up mostly carapace specimens.

 

This find has really caused the fossil hunting bug in my 5 and 7 yr old. They can't believe I pulled this out when they were getting the standard devil's toenails and other tiny bits of shell. They are already begging to go out on another expedition! 

[erose]

Pagurus banderensis occurs in the Walnut Formation as well. I believe the park may expose some of that formation.  That is a nice claw. They are not rare, but good ones are always a bonus. 

[madness]

Sometimes I have a hard time figuring out what formation I'm really looking at. For the past year or so, I was using the USGS geological overlay on Gaia GPS (an iphone app for tracking hiking, etc). But I've come to realize just how coarse that information is (probably because it's all stored on your phone for when you are out of service area). So I've been using https://txpub.usgs.gov/dss/texasgeology/ but sometimes you can't quite tell where the roads are and when you are near a formations border, I'm pretty unsure! 

 

I've shown this piece to my whole Austin family now. No one else has every picked up or seen a claw like this, though they are all quite familiar with the more common ones (probably just because those were common in our backyard creek). Everyone wants to go on our next expedition!