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Trilobite Eggs Discovered!


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On 7/18/2013 at 4:57 PM, Auspex said:

This does look like oolites.

But, the joke begs the question: have trilobite eggs ever been identified? Anyone know?

 

This great question from Auspex a couple years ago can now be answered in the affirmative. Up until now there have been a few close calls but nothing conclusive. The earliest reference to alleged trilobite eggs was made by Joachim Barrande in 1872. C.D. Walcott also published a brief paper in 1877 and each of these were subsequently disproved by Percy Raymond in 1931. Zhang and Pratt 1994 also reported on possible eodiscid embryos but had to concede that they may have been produced by another soft-bodied arthropod.

 

Now at long last we finally have what appear to be bona fide trilobite eggs. Not surprisingly, the remarkable preservation of pyritized Triarthrus specimens from New York have yielded this highly anticipated fossil gold.

 

Pun intended, Enjoy! :1-SlapHands_zpsbb015b76:

 
PYRITIZED IN SITU TRILOBITE EGGS FROM THE ORDOVICIAN OF NEW YORK (LORRAINE GROUPE):
IMPLICATIONS FOR TRILOBITE REPRODUCTIVE BIOLOGY
 
Hegna, Thomas, Martin, Markus, Soriano, Carmen (2015)
 
Geological Society of America - North-Central Section - 49th Annual Meeting (May 19-20)
Paper No. 20-3 - Presentation Time: 8:45 AM
 
Despite a plethora of exceptionally preserved trilobites, trilobite reproduction has remained a mystery. No trilobite has preserved unambiguous eggs or genitalia. This study reports on the first occurrence of preserved, in situ trilobite eggs from Triarthrus eatoni from the Lorraine Group in upstate New York. Like other exceptionally preserved trilobites from the Lorraine Group, the trilobites are replaced with pyrite on their exoskeletons and ventral appendages. The eggs (presumably representing unfertilized eggs) are spherical to elliptical in shape, about 50 µm in size, and are clustered in the genal area of the cephalon near the lateral border. The eggs are only visible ventrally with no dorsal brood pouch or recognized sexual dimorphism. This location is consistent with how modern horseshoe crabs carry their unfertilized eggs. Trilobites likely released their gametes (eggs and sperm) through a genitalia pore of as-yet unknown location (likely near the posterior boundary of the head). If T. eatoni’s reproductive biology is representative of other trilobites, they spawned rather than mated and exhibited r-strategy reproduction. A more detailed view of the anatomy associated with the eggs in currently in progress with synchrotron x-ray tomography.
 
 
Barrande, Joachim (1872)
Systême Silurien du centre de la Bohême. 1 ère Partie. Recherches paléontologiques, Supplement au Vol.I:
Trilobites, Crustaces divers et Poissons, (Prague and Paris)
 
Walcott, C.D. (1877)
Note on the Eggs of the Trilobite.
Annual Report of the New York State Museum of Natural History, 31:66-67
 
Raymond, P.E. (1931) Capsule-shaped "Eggs" 
In: Notes on invertebrate fossils, with descriptions of new species.
Bulletin of the Museum of Comparative Zoology, 55:165-213
 
Zhang, X.G., & Pratt, B.R. (1994)
Middle Cambrian arthropod embryos with blastomeres.
Science, 266:637-639
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I have wondered about this ever since I first learned what trilobites were...

What a discovery!post-423-0-20948300-1426287788.gif

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amazing, and NY, no less...another fossil goes on the bucket list :)

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WOW! any pix? :goodjob:

According to the abstract it sounds like the images are still in the works. Hopefully a published paper is coming soon as well.

A more detailed view of the anatomy associated with the eggs is currently in progress with synchrotron x-ray tomography.
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A logical assumption has finally been verified. It should certainly be interesting to read a published paper about it.

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Way to go Markus!!!!!!! If eggs were to be found a good place to look would have been on his "goldbugs"

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  • 10 months later...
While looking for some unrelated material I stumbled across additional info on the alleged trilobite eggs from Zhang & Pratt 1994.
Evidently they were found to be worm eggs. It's also worth mentioning that Zhang & Pratt agree as co-authors of this recent paper:
 
 
Quote
The first phosphatized embryos were recovered from the middle Cambrian (Stage 5) Gaotai Formation in Duyun (Zhang and Pratt, 1994). Completely unexpected, these stirred considerable excitement and provoked a worldwide search for embryos in comparable limestones. The minute embryos were initially presumed to be of arthropod affinity because they occurred with many phosphatized eodiscoid trilobite protaspides—the only larval form in the same strata. However, a number of prehatching ‘egg-larvae’ (Fig. 2A and B , including Markuelia coiled within their egg membranes, were subsequently discovered from the original limestone bed (Zhang et al., 2011). These are oblate spheroid-shaped, and are roughly the same size as other known cleavage embryos (Fig. 2C). Thus the postulated trilobite affinity for the original specimens is incorrect and, rather, they belong to this scalidophoran worm taxon.
 
Shen, C., Pratt, B.R., Lan, T., Hou, J.B., Chen, L., Hao B.Q., & Zhang, X.G. (2013)
The search for Orsten-type fossils in southern China.
Palaeoworld, 22:1-9
 
 
 
 
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While looking for some unrelated material I stumbled across additional info on the alleged trilobite eggs from Zhang & Pratt 1994.

Evidently they were found to be worm eggs. It's also worth mentioning that Zhang & Pratt agree as co-authors of this recent paper:

So my question is, did the eggs settle by the trilobite or were they purposely laid on the trilobite so when they emerge a food source was immediately available?

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So my question is, did the eggs settle by the trilobite or were they purposely laid on the trilobite so when they emerge a food source was immediately available?

My gut instinct is the latter, but we'll probably never know. It is possible too that the trilobite was there to eat the eggs...

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On 1/28/2016 at 7:49 AM, Raggedy Man said:

So my question is, did the eggs settle by the trilobite or were they purposely laid on the trilobite so when they emerge a food source was immediately available?

On 1/28/2016 at 7:55 AM, Auspex said:

My gut instinct is the latter, but we'll probably never know. It is possible too that the trilobite was there to eat the eggs...

 

 

The worm eggs were not laid on or near a mature trilobite. The worm eggs were found associated with trilobite larvae:

 

"The first description of Cambrian embryos was based on a few embryos of cleavage stages, which Zhang and Pratt (1994) had originally attributed to arthropods, presumably trilobites because eodiscoid protaspides were the only fossil larvae recovered in the same rocks."
 
Zhang, X.G., Pratt, B.R., & Shen, C. (2011)
Embryonic development of a middle Cambrian (500 myr old) scalidophoran worm.
Journal of Paleontology, 85(5):898-903
 
 
 
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  • 4 months later...

This highly anticipated paper has finally been published.

 

Enjoy! Posted ImagePosted ImagePosted Image

 

Hegna, T.A., Martin, M.J., & Darroch, S.A. (2017)

Pyritized in situ trilobite eggs from the Ordovician of New York (Lorraine Group): Implications for trilobite reproductive biology.

Geological Society of America, Geology, 45(3):199-202

 

OPEN ACCESS PDF

 

 

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Great paper been waiting to read. Amazing preservation no doubt what they are.....

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We have come a long way from the first alleged trilobite eggs reported by Barrande and Walcott in the 1800's.

For an interesting historical perspective, here is Walcott's description and the subsequent rebuttal by Raymond. 

 

IMG1.jpg

 

Walcott, C.D. (1877)
Note on the Eggs of the Trilobite.
Annual Report of the New York State Museum Natural History, 31:66-67

 

IMG2.jpg

 

Raymond, P.E. (1931) Capsule-shaped "Eggs" 
In: Notes on invertebrate fossils, with descriptions of new species.
Bulletin of the Museum of Comparative Zoology, 55:165-213

 

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  • 2 weeks later...
On 1/13/2017 at 10:23 AM, piranha said:

This highly anticipated paper has finally been published.

 

Enjoy! Posted ImagePosted ImagePosted Image

 

Hegna, T.A., Martin, M.J., & Darroch, S.A. (2017)

Pyritized in situ trilobite eggs from the Ordovician of New York (Lorraine Group): Implications for trilobite reproductive biology.

Geological Society of America, Geology, 45(3):199-202

 

OPEN ACCESS PDF

 

 

 

 

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