SQUIDCAM 2: Fossil Cephcam

Phil obviously used the new Binford 9000 nuclear incubator, with the 32.3 gigawatt flux capacitor to incubate fossil ammonoid and nautiloid eggs. So he should have some left over to photograph. :notworth:

From what I can gather, Nautilus eggs are very large, about 1" (25mm) and ammonoid eggs were small, about 1/32" (1mm). See a newly hatched nautilus here. Some rocks are full of ammonitellas, the initial chamber of the ammonoid shell, (you can see an ammonitella in the center of my avatar), these are possibly either egg masses or deposits of alot of newly hatched ammonoids.
 
Steve,

I done a little poking around for you and it seems that unfortunately fossil nautiloid eggs are unknown. That said, estimates of the size of hatchling nautiloids have been made based on the size of the protoconch, the shell that develops inside the egg before hatching. As eggs are unknown I suppose it is impossible to guess whether these eggs were deposited individually or in strings; that’s simply something we will never know for certain unless an exceptionally unlikely fossil turns up. Given this, I very much doubt that any ammonoid eggs are known given that they are believed to be a magnitude smaller.

According to Prof. Theo Engeser’s Nautiloidea Homepage the Recent Nautilus has an embryonic conch of just over 3cm which makes it the largest of all the nautiloids with seven completed septa by the time it hatches. Fossil forms were probably smaller but still much larger than the ammonoids, which as Kevin has pointed out, were planktonic in size. It is believed that ancient nautiloids never hatched with under three septa completed in the embryonic form, and most hatched with more. Engeser also states that the average nautiloid diameter (or length) of the embryonic conch is about 2 cm or less. I suppose with fewer complete septa development time must have been less. It would be certainly nice to find out at what stage in development orthoconic nautiloids hatched and how large they would have been.

Diminishing size of hatchlings, and an increasingly faster growth rate (?) seems to something that the ammonoids developed . This might help explain why the ammonites varied and speciated so quickly, whereas the nautiloids and Nautilida seemed to be so consistant and resistant to alteration. One took the sluggish, slow, cold and stable path, whereas the other evolved for a fast short lived shallow water lifestyle, breeding fast and dying young and fell victim.

Of interest and relevance here is also this .pdf article Anomalies of embryonic shell growth in post-Triassic Nautilida by Regis Chirat.

Phil
 
On another note, I checked my NAUTILOIDCAM when I got back from work this evening and got an eyeful! Blimey, these things grow quick! See what I mean?

Latest Candid Cameroceras image for you:

Nautiloidcam2.PNG
 
Cephkid said:
Phil, no offense but...er...it isn't that big, you've just got the camera zoomed in all the way!

Er, doh! I never thought of that.....too much Guiness this evening! :biggrin2:
 
Update today from the third and final tank: BELEMNCAM.

Just two survivors here; luckily I managed to catch an image of both of them. These belemnites have been the easiest to feed so far; I've tried a diet of copepods which they enjoyed shortly after hatching. At three weeks I moved onto mysid shrimps. Now after six weeks they have reached a good four inches in length. I am slowly trying to introduce a diet of small crabs. I've had to install a sump and am running the chiller at 25 degrees to simulate early Cretaceous conditions in the Tethys Sea.

By the way, the orthoconic nautiloids are the hardest to feed. I've had to substitute trilobites for other crustaceans. Trilobites are, of course, extinct and one obviously cannot get hold of them.

Belemncam.PNG


(Is this joke getting boring yet?)
 
"Trilobites are, of course, extinct and one obviously cannot get hold of them.
"heheh...
as far as boring goes...certainly not! I laud your photoshop skills...hey, this is the guy who will keep on hashing on the Miskatonic for the next decade or so... :shock:
 
Hmm....

Well following Steve's observation over at SQUIDCAM that the introduction of a small crab enabled the squid egg masses to remain comparatively clear of bacterial build up, I decided to adopt a similar policy over at NAUTILOIDCAM.

Unfortunately, as has already been stated, I cannot obtain trilobites for love of money as they are extinct. Instead I plumped for using a juvenile sea scorpion (the Ordovician eurypterid Megalograptus) to see if it would perform a similar function.

Initially the sea scorpion ("Mr Nips") settled on the egg masses and groomed them with his chelicerae as one can see in the cam shot below.

Nautiloidcam271104.PNG


I thought all was going according to plan when I returned an hour later and found that one of the Nautiloids, ("Sir Hugo the Bold") had consumed the sea scorpion. Oh no! I just caught a fleeting glimpse of the fatal moments before turning the camera off in disgust. I had forgotten completely about the predator/prey relationship.

Farewell, Mr. Nips.

Nautiloidcam261104.PNG
 
Interesting parallel.

One thing that really concerns me is the thickness of your tanks. Those things are growing faster than triffids, and if you don't look out you're going to become a snack next feeding time!

I was speaking to a jolly good lad over here a few days ago (Nik from Kelly Tarlton's). I pulled a bottle of pickled fish off the shelf and muttered something along the lines of 'what on Earth are those'. He responded 'juvenile Bluefish' - normally a very deep-dwelling thing (several hundred metres). I then asked 'where did you get them' - the answer - drift algae on the surface of Le Ocean. Most interesting it was!!!

Normally you skirt from A to B in a terrible hurry, trying to get somewhere and working with or against the tides and day length, or you're just ambling along at 2.5knots with a fine ringnet out the back. It got me thinking .... Nik said you often get a few of these deep-sea fish in the drift weed, and perhaps this is one mighty cool habitat to go looking for larval squid (ammonites, belemnites and nautiloids also).

My rambling has a point (I hope). When did seaweeds first appear?? If you had rafts of these things (weeds) might it not be an appropriate habitat in which to look (or photoshop) for juvenile ammonites, belemnites and nautiloids .... If not weeds then perhaps the buoyant rafts of dead ceph (ammonite/nautiloid) shells would have done the trick (surely there were rafts of these things in the good ol' days, with myriad epiphyte growths and elevated diversity and density of associated taxa ... aka baby ammonite food).

Next time I'm out in the blue I'll be dip-netting these recent weed rafts on the offchance I'll find juvenile squid taking refuge in them (and dining on the wee island of small fish that seem to cohabit them); I'd imagine a weed raft would be a safer place to hide than the open ocean.
 
The following pics show what may be small ammonoids (along with a plethora of other things, most common is probably bivalve spat) filling the living chamber of Prionocyclus novimexicanus. This fossil came from a concretion that possibly formed around a algal "raft" or matte.

When spring comes I will go out and study these concretions a little closer.

download.php

download.php

download.php
 
Not snowing down this way .... tiz a hot and sunny day in fact :biggrin2:

Neat pic - those tiny wee things in the last chamber!! Fortunately you've got something else in there (bivalve or not) as it would be so easy (for a pleb like me) to jump to the conclusion that this was possibly a brood/brood chamber.

Hope the weather picks up soon! (Or do you like this time of the year?)
 
Another ?interesting point is that umbilicate gastropods (Recent) sometimes brood in the umbilicus.
 

Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
Back
Top