Ask Dr. Barord (aka, Dr. Nautilus)...

Great idea! I have a few questions and would love to hear what you think.

1) How many scientists are actively working on nautiluses? My impression is that there's little room for cephalopodologists in modern biology (for a number of reasons), let alone specialists in smaller groups.

2) How well do we know the anatomy of nautiluses? From what I remember about nautilus taxonomy a lot of the diagnostic features are vague and based on gross morphology.

3) Nautilus shells have been popular since the early modern period in cabinets or curiosities and Wunderkammers. Is there anything we could learn from historic populations by sampling all those 17thC bling bling shells (some e.g.s here) in art museums?
 
Oh man, all those Nautilus questions that have never been answered... hmmm... So, the siphuncle placement of Ammonites and Nautilus are different, how do you think this might affect septal shape and buoyancy regulation?

@cuttlegirl , heck of a first question! I've been looking into it more since my background in Paleontology is not the best... I've also sent an email off to a couple colleagues to get their more expert thoughts on it. More soon!

Dr. Barord
 
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Soft‐tissue imprints in fossil and Recent cephalopod septa and septum formation Just found this article, I always wondered how both Nautilus and Ammonite formed the new septum and held on to their shell while moving forward into the new space. Must be a point where the connection to the shell is somewhat tenuous.

@cuttlegirl , This is only anecdotal, but I've observed two nautiluses that have come almost entirely out of their shell on different occasions and were found on the bottom of the tank with tentacles attached to the bottom. At first, I figured this meant we'd find a dead nautilus soon, but they went back into their shell and survived with no apparent problems. I've asked a few folks and have heard of a few similar instances. Could this be part of the "moving forward" of nautiluses when making new septal walls?

Dr. Barord
 
Great idea! I have a few questions and would love to hear what you think. 1) How many scientists are actively working on nautiluses? My impression is that there's little room for cephalopodologists in modern biology (for a number of reasons), let alone specialists in smaller groups. 2) How well do we know the anatomy of nautiluses? From what I remember about nautilus taxonomy a lot of the diagnostic features are vague and based on gross morphology. 3) Nautilus shells have been popular since the early modern period in cabinets or curiosities and Wunderkammers. Is there anything we could learn from historic populations by sampling all those 17thC bling bling shells (some e.g.s here) in art museums?

@Mark Carnall , Thanks for the questions!

1. I think there are only a few with a directed and dedicated focus on nautiluses. I would say there are a handful (less than 10) scientists working on a less dedicated basis with nautiluses. I don't mean only specifying on nautiluses, but they definitely have a nautilus focus. And there are a few dozen working with nautiluses in some capacity. I think there's little room for specialists in many groups going forward, unfortunately, but having a specialty is still very important to progress. I think "cephalopodologists" are poised for a big breakthrough going forward with the growing focus on cephalopod fisheries, behavior, etc., and having folks with that specialty, while also having a broad background. Think of a brain surgeon. Sure, they focus on the brain, but they also have enough background to be able to apply different areas of medicine to their focus and vice versa.

2. The understanding of nautilus anatomy has come a long way. The basic anatomy is pretty well researched but there have been some pretty interesting papers and studies using new methods of photographing and investigating the different parts. Regarding taxonomy, there is a definite shift in adding genetics to the mix as with many species, which helps out immensely.

3. This is a great question! With so much focus on nautilus conservation now, it would be wonderful if we could somehow recreate populations from sampling shells in museums, etc. I am not sure how you'd do it though. The whole shell is one thing, but how do you account for small items such as jewelry or inlays... There are definitely other methods of estimating past populations, but not sure if this could be used. But hey, with enough data and analyses, you might be able to find something interesting.

Dr. Barord
 
@gjbarord thanks for the answers! Especially to number 1. The loss of specialists who work within a group is a growing concern in biology but it seems that cephapodology has always been a niche science, hence so many unexplored questions!

Question 3 is close to my thoughts at the moment. Looking at OUMNH's Nautilus collections (and cephalopods in general) I'm always asking, how useful are our collections for contemporary science. Considering nautilus collections are mostly shells (we have some fluid preserved material) I'm curious as to how useful malacology collections are.

Wow to the answer to @cuttlegirl question about nautiluses 'coming out' of their shells.

Thanks again for the answers.
 
@cuttlegirl , This is only anecdotal, but I've observed two nautiluses that have come almost entirely out of their shell on different occasions and were found on the bottom of the tank with tentacles attached to the bottom. At first, I figured this meant we'd find a dead nautilus soon, but they went back into their shell and survived with no apparent problems. I've asked a few folks and have heard of a few similar instances. Could this be part of the "moving forward" of nautiluses when making new septal walls?

Dr. Barord
Greg, do you remember how long the nautiluses stayed partially out of their shells (hours, days?)
 
@cuttlegirl , This is only anecdotal, but I've observed two nautiluses that have come almost entirely out of their shell on different occasions and were found on the bottom of the tank with tentacles attached to the bottom. At first, I figured this meant we'd find a dead nautilus soon, but they went back into their shell and survived with no apparent problems. I've asked a few folks and have heard of a few similar instances. Could this be part of the "moving forward" of nautiluses when making new septal walls?

Dr. Barord

So here are some thoughts... and that it is an interesting observation. So, there are muscle attachments to the side of the shell. So at some point, they need to "let go" and move forward into the new space. That could either be accomplished by "creeping" the muscle attachments or by "letting go" and reattaching. Of course there could be an entirely different process too...
 
If that truly is how they move forward in their shell, it seems that would be extremely vulnerable to predators.

I can't imagine that ammonites would have the same method because replication of the septal shape would be difficult. I always imagined that ammonites would have attachment points at the lobes and then pull forward. Unless of course, the part of the ammonite in direct connection with the septum was stiff and then it could just recreate a mold of the shape.
 
@cuttlegirl , I'll start that this is pure speculation on my point... But, there is data pointing to the fact that nautiluses in Australia stop at around 200m during migrations to presumably regulate their buoyancy back to neutral after deep migrations. This would surely be a highly dangerous move for predation but at 200m there are rocks and structure, so the nautiluses may be able to hide-out while they get back to normal. Maybe they can also do this when moving in their shell forward... But then again, why haven't these observations been made by more people?

Greg
 
Hi Greg,
I've been trying to find information on chambered nautilus immune system, but I haven't find anything, and as a fact I haven't find anything regarding cephalopods in general. Do you know anything regarding the immune system on the chambered nautilus?

By the way all that information about Nautilus moving forward into the new septum is amazing! what a great question @cuttlegirl.
 

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