Dinosaur Fossil Friday

[Malone]

Thank you again bobby I sent these pictures to my granddaughters although one isn't probably old enough to be interested in yet. I want my granddaughters to see the amazing things that have been created and I hope that you keep learning about them!

[piranha]

6 hours ago, Troodon said:

The extraordinary "trident" trilobite Walliserops trifurcatus - one of three described species in this genus.  The function of the trident remains unknown ... and probably unknowable! 

 

 

There are four species of Walliserops:

 

Walliserops trifurcatus Morzadec 2001 

Walliserops hammii Chatterton et al. 2006

Walliserops tridens Chatterton et al. 2006

Walliserops lindoei Chatterton & Gibb 2010

 

 

Fortunately, we have some well-reasoned understanding, as the experts have already weighed in on this topic:

 

Three species of Walliserops are found in the same beds: W. trifurcatus Morzadec, 2001, W. tridens new species and W. hammii new species.  The largest specimens discovered of the latter two species are about half the length of large specimens of the former species.  Specimens of these three species that are the same size are sufficiently different in form that they cannot be different ontogenetic stages of the same species.  This, again, raises the question of whether sexual dimorphism or polymorphism may be present in an asteropygid trilobite genus.  Some modern arthropods have at least three forms (e.g. bees, with queens, workers and drones), but only in relation to social habits that are unlikely for trilobites.  Differences in morphology, size, and relative abundance of the three species of Walliserops found in ZGEE1, when combined with an absence of knowledge in regard to similar co-occurrences in other localities, preclude our proposing that they belong to one or more polymorphic species.

 

Chatterton, B.D.E., Fortey, R.A., Brett, K.D., Gibb, S.L, & McKellar, R.C. (2006)
Trilobites from the upper Lower to Middle Devonian Timrhanrhart Formation, Jbel Gara et Zguilma, southern Morocco.
Palaeontographica Canadiana, 25:1-177    PDF LINK

 

 

The trident anterior cephalic process is the most distinctive feature of Walliserops.  The largest trident known for this genus, in the proportion of the length of the trident to that of the exoskeleton, belongs to W. trifurcatus, where it is 78% of the length of the rest of the exoskeleton, or 43% of the length of the whole exoskeleton.  It increased the size of the animal substantially, perhaps discouraging smaller predators from attacking it.  Large predators occur in a trophic pyramid in lower numbers than small predators.  If a species increased its size so that the size of the predators that would prey upon it also increased, it would reduce the chance of being preyed upon because there would be fewer of these large predators in the community to find it.  The sharp tines of the trident, combined with numerous marginal and dorsal spines would also have reduced the appeal of Walliserops as prey.  It is doubtful that the trident could or would have played an important role in feeding (it is not directed downward for digging), reproduction (unless sexual selection or brooding were involved) or respiration (the thick shelled haft and solid tines would have allowed little gas exchange).  While it is usual when suggesting functions for structures on fossils to suggest that each structure primarily performed a single task associated with some vital function, in reality some structures perform several tasks.  Thus, the trident functioned primarily for defense, but could have performed a role in sexual selection, and/or brooding.  It might even have performed a hydrodynamic function by extending the leading edge forward when the animal was facing into a bottom current and creating eddy currents around the dorsally directed spines on the rest of the cephalon and farther back.  This might have reduced drag in some circumstances.  Flume experiments could be used to test this hypothesis but they are beyond the scope of the present work.

 

Chatterton, B.D.E., & Gibb, S.L. (2010)
Latest Early to Early Middle Devonian Trilobites from the Erbenochile Bed, Jbel Issoumour, Southeastern Morocco.

Journal of Paleontology, 84(6):1188-1205

 

 

As the spines were moulted together with the whole exoskeleton, their curvature was not an outcome of basal growth, but it certainly reduced their defensive value.  Therefore, it is here assumed that we deal, as in a ram’s horns, with a product of sexual selection.  This hypothesis implies, however, that the eyes of the partners provided a sharp enough picture to appreciate such beauty.  The same argument may explain the long rostra of Psychopyge and Walliserops.  They were in the way of enrolment, too blunt for a weapon, and useless as a mouth organ.  But they could be used to turn the competitor on its back in a ritual fight.  Co-occurring dimorphs may corroborate these speculations in the future.

 

Seilacher, A. (2013)

Patterns of macroevolution through the Phanerozoic.

Palaeontology, 56(6):1273-1283

[Bobby Rico]

1 hour ago, Malone said:

Have you ever heard a mass of cicadas come up from the ground after approximately 17 years and sing or play in unison? It's a curious thing how groups of creatures will seek to harmonize. I thank you! My granddaughters will be thrilled to see these!

Thank you. It is a silly picture indeed. I love adding  to this thread of Troodon’s it is really is diverse and enjoyable. I have never heard cicadas but I would really like to hear what you described . 

[Troodon]

4 hours ago, piranha said:

 

 

There are four species of Walliserops:

 

Walliserops trifurcatus Morzadec 2001 

Walliserops hammii Chatterton et al. 2006

Walliserops tridens Chatterton et al. 2006

Walliserops lindoei Chatterton & Gibb 2010

Thanks for the update, will give the feedback to the individual who provided the info for my post.

[Bobby Rico]

sorry I know it is Saturday but I just spotted this and wanted to add to my Crystal Palace post. 

Dicynodon  looks much like a sabre toothed tortoise. 

[Stu]

Could these photos include the Twitter handles of the original posters? Thy should be credited.

[Troodon]

5 hours ago, Stu said:

Could these photos include the Twitter handles of the original posters? Thy should be credited.

In a perfect world yes and what I was going to do but its an onerous task with the number photos involved.  However you are correct and will need to reconsider continuing this topic.  

[Bobby Rico]

33 minutes ago, Troodon said:

In a perfect world yes and what I was going to do but its an onerous task with the number photos involved.  However you are correct and will need to reconsider continuing this topic.  

That will be a shame to stop this topic but I understand. I am an digital Artist and if I google my name I can find my work on lots of websites that I did not know anything about . It does not bother me, it is part of having a web presence. As long as my works are not been reprinted to be sold . I see it as publicity  and as most of the fossil on this thread are from museums , I can only see it as a good thing for the museum to get some free publicity too. 

 

 

[Malone]

3 hours ago, Bobby Rico said:

That will be a shame to stop this topic but I understand. I am an digital Artist and if I google my name I can find my work on lots of websites that I did not know anything about . It does not bother me, it is part of having a web presence. As long as my works are not been reprinted to be sold . I see it as publicity  and as most of the fossil on this thread are from museums , I can only see it as a good thing for the museum to get some free publicity too. 

 

 

I just posted a thassaloides picture on the forum and if I search thassaloides on the web the picture pops up as a result.

[Stu]

I didn't mean too stop the topic! Many of the captions are straight copy and pastes from the tweets, so it's not much work to include the credit and would be useful and proper for photographers, artists and users.

[The Amateur Paleontologist]

Hey everyone, I decided for once to make my own little contribution to the Dinosaur Fossil Friday. I know it's not Friday today (I was busy on the 18th and 19th), but anyway - let's keep this thread alive and going! 

 

Exquisitely preserved skeleton of Saurornitholestes langstoni from the Late Cretaceous of Dinosaur Provincial Park, Alberta (held in the collections of the University of Alberta).

 

Skull and cervical vertebrae of a small Halisaurus arambourgi from the Late Cretaceous of Ouled Abdoun, Morocco (was for sale at a fossil fair, 1500€)

[The Amateur Paleontologist]

Continued...

 

Neat little Muramatoceras yezoense from the Late Cretaceous Yezo Group of Hokkaido, Japan (Natural History Museum of Milan)

 

 

3D-preserved skeletal remains of Nothosaurus sp. from the Triassic of Lorraine, France (Oxford University Museum of Natural History)

 

 

There's more to come later today… Stay tuned  

 

[Tidgy's Dad]

 

3 hours ago, The Amateur Paleontologist said:

There's more to come later today… Stay tuned  

 

How nice to see the return of Dinosaur Fossil Friday. 

Thank you. 

[digit]

Next best thing to the return of the dinosaurs themselves.

 

I do enjoy the eye candy in this weekly post.

 

 

Cheers.

 

-Ken

[The Amateur Paleontologist]

Glad you guys like it!  

 

Here's the next installment… 

 

Well preserved associated test and spines of at least one Prionocidaris vendocinensis echinoid from the Late Cretaceous Chalk of England (Oxford University Museum of Natural History)

 

Almost complete skull of Linheraptor exquisitus from the Late Cretaceous of Inner Mongolia, China (Institute of Vertebrate Paleontology and Paleoanthropology)

 

Partial mandible of a thoracosaurine crocodile from the Maastrichtian Chalk of Møns Klint, Denmark - a unique find over there. Specimen is held at GeoCenter Møns Klint.

 

 

Expect more stuff next week! 

 

[hxmendoza]

That picture of the Linheraptor skull is pretty cool. Where’d you find it?

[The Amateur Paleontologist]

@hxmendoza I took the picture during my visit of the IVPP.

[hxmendoza]

1 hour ago, The Amateur Paleontologist said:

@hxmendoza I took the picture during my visit of the IVPP.

 

Lucky you!

Any other pics of the skull? Any pics of any Velociraptor or other Dromaeosaur material from there?

[The Amateur Paleontologist]

@hxmendoza Sorry I don't have many pictures (some of them are blurry), but I can show you some things

 

Closeup of the Linheraptor skull

 

Sinovenator changii holotype skull (I know it's not a dromaeosaur, but it's still cool! )

 

Right forelimb plumage from the holotype specimen of Microraptor gui

 

 

I'm afraid that's it for the relatively good-quality pictures  Hope you liked them anyway

[hxmendoza]

Thanks!

[The Amateur Paleontologist]

Next Friday: a few fossils from the Pterosaur and Dinosaur collections of the Natural History Museum of London

[Bobby Rico]

1 hour ago, The Amateur Paleontologist said:

Next Friday: a few fossils from the Pterosaur and Dinosaur collections of the Natural History Museum of London

Please and thank you. Can’t wait 

[The Amateur Paleontologist]

Hello all

 

I'm going to launch this new Dinosaur Fossil Friday with some neat fossils from 2 British museums: the Oxford University Museum of Natural History (OUMNH), and the Natural History Museum of London (NHMUK). Enjoy! 

 

Left maxilla and premaxilla of Iguanodon mantelli from the Late Cretaceous of Tilgate Forest, England (OUMNH)

 

Well preserved calyx, arms and stem of Encrinus liliiformis (OUMNH) from the Triassic Muschelkalk of Germany

 

Rather complete skeleton of Pterodactylus kochi from the Solnhofen Limestone (Mid-Late Jurassic of Germany) - note the few areas where pycnofibres (pterosaur integument) are preserved (OUMNH)

 

 

It's not finished… Far from it, actually  

[Bobby Rico]

33 minutes ago, The Amateur Paleontologist said:

Encrinus liliiformis (OUMNH) from the Triassic Muschelkalk of Germany

Nice to see a crinoid with a terrestrial location   

 

 

Thank very much if get the chance I will try and add to this . 

[The Amateur Paleontologist]

@Bobby Rico Alright, that sounds good  

 

More fossils from British museums...

 

The Yarnton Pliosaur (Peloneustes philarcus); a fairly complete pliosaur skeleton discovered in 1994 in the Oxford Clay (Jurassic) of Yarnton (OUMNH)

 

Assemblage of Ridersia watsoni cystoids from the Middle Cambrian of Queensland, Australia (NHMUK)

 

Caudal vertebrae of Edmontosaurus from the Late Cretaceous of Alberta (Dinosaur collections of the NHMUK)

 

Distal end of an opalised Fulgurotherium australe femur from the Aptian-Albian (Cretaceous) of Lightning Ridge, Australia (Dinosaur collections of the NHMUK)

 

Dentary of Nuthetes destructor (British dromaeosaurid) from the Early Cretaceous Lulworth Formation, South England (Dinosaur collections of the NHMUK)

 

Stay tuned for more…