Extant Pristis pristis (Largetooth Sawfish) rostrum

[MarcoSr]

A post by Tony on STH teeth a while back peaked my interest in extant sawfish rostral teeth.  The two extant sawfish genera are Pristis and Anoxypristis.   There is only a single extant Anoxypristis species, Anoxypristis cuspidata (Knifetooth or Narrow Sawfish).   There are 4 extant species of Pristis, Pristis clavata (Dwarf Sawfish), Pristis pectinata (Smalltooth Sawfish), Pristis pristis (Largetooth Sawfish), and Pristis zijsron (Green Sawfish) Last 2016.  This post is about a Pristis pristis (Largetooth Sawfish) rostrum.

 

If you would also like to see pictures of an Anoxypristis cuspidata rostrum and/or a Pristis pectinata rostrum check out my previous TFF posts at the links below:

 

http://www.thefossilforum.com/index.php?/topic/83865-extant-anoxypristis-cuspidata-knifetooth-or-narrow-sawfish-rostrum/&tab=comments#comment-895466

 

http://www.thefossilforum.com/index.php?/topic/86239-extant-pristis-pectinata-smalltooth-sawfish-rostrum/&tab=comments#comment-932077

 

Below is a picture of a Pristis pristis sawfish and other information from Last, White, de Carvalho, Seret, Stehmann, Naylor 2016 “Rays of the World:

 

 

 

This rostrum is 19.5 inches by 3.5 inches at the posterior most rostral teeth.   Pristis pristis rostrums have 14-24 equally spaced rostral teeth per side with the posterior most teeth located near the base of rostrum.  This rostrum has 19 left and 18 right rostral teeth (Note one tooth is missing on the left side) and is shown below in dorsal and ventral views:

 

     

 

 

Here is the basal view of the rostrum (shows a thin layer of skin with a good amount of cartilage visible):

 

 

 

Dorsal side, two pictures of placoid scales on the rostrum surface with the second picture a close-up picture:

 

 

 

Ventral Side, two pictures of placoid scales on the rostrum surface with the second picture a close-up picture:

 

 

 

Continued in next reply

 

Marco Sr.

 

[MarcoSr]

Below are pictures of 8 different rostral teeth (14 mm to 28 mm vertical height)

 

6 teeth dorsal views.

 

Left (28 mm) and right (25 mm) side first anterior teeth (note you can clearly see the posterior groove in the rostral tooth in the first picture):

 

 

 

Left (19 mm) and right (28 mm) side middle teeth:

 

 

 

Left (14) and right (20 mm) side last posterior teeth:

 

 

 

2 teeth, left (22 mm) and right (22) side second anterior teeth, ventral views:

 

 

 

Unfortunately now Pristis pristis is a critically endangered species.  Over fishing has not only drastically reduced their numbers but it has also greatly reduced the size of the largest members of the species.  Populations are now restricted due to likely extinction through much of its original range.

 

I put the below data together for Pristis pristis rostrums from Last, White, de Carvalho, Seret, Stehmann, Naylor 2016 Rays of the World and from Matthew T. McDavitt 2004 Sawfish Recovery Team Meeting PowerPoint presentation and similar data for each other sawfish species to help me to distinguish sawfish rostrums.

 

 

 

Note however that color of the rostrum is not a reliable feature as the preservatives used during taxidermy and aging can change the colors.  As an example the ventral sides of all living sawfish rostrums is white to whitish.  Yet pretty much every taxidermy rostrum that I see has a yellowish to light brownish ventral color.  Also pictures can really distort the colors especially when using flash.  You need to see the rostrum in natural light for the best color representation.

 

You can see the measurements I used in the below picture:

 

 

 

For this rostrum:

 

ISP= 24 mm, ISA= 19 mm, ISP/ISA = 1.26

 

SRL=18.25”, RWP=3.5”, SRL/RWP=5.21

 

So the measurements of this rostrum, the number of rostral teeth, and the rostral tooth features and rostral tooth positioning on the rostrum all fall within the parameters of a Pristis pristis rostrum.

 

Marco Sr.

[Fossil Claw]

When I saw the title at first I thought this was going to be a joke about Harry.

 

@Harry Pristis

[Tidgy's Dad]

Thanks Marco Sr. 

Another great post. 

[ynot]

Thanks again Marco!

[Al Dente]

Marco-

Nice photos. We discussed Anoxypristis back in April and I wasn't sure if there were placoid scales or not on the surface of that particular rostrum. Looking at your photos on this thread, I'm pretty sure these are placoid scales on the surface of the rostrum. The Casier diagram is showing prismatic cartilage that forms the structure under the skin. We find this prismatic cartilage frequently in the Eocene Castle Hayne Formation of NC. Here is the Casier diagram and some photos I took of one of my Pristis lathami fragments. You can see the calcified cartilage pillars with radiating spokes.

 

[Al Dente]

Here is a description of a pristis rostrum describing the placoid scales. Unfortunately the author mixed up the photos with the wrong description for the scales. I think the second photo shows the correct description for the first photo. The paper is "The Identification, Structure, Care, and Conservation of Sawfish Rostra (Rhinopristiformes: Pristidae)" Jessica Byler.

[MarcoSr]

2 hours ago, Al Dente said:

Marco-

Nice photos. We discussed Anoxypristis back in April and I wasn't sure if there were placoid scales or not on the surface of that particular rostrum. Looking at your photos on this thread, I'm pretty sure these are placoid scales on the surface of the rostrum. The Casier diagram is showing prismatic cartilage that forms the structure under the skin. We find this prismatic cartilage frequently in the Eocene Castle Hayne Formation of NC. Here is the Casier diagram and some photos I took of one of my Pristis lathami fragments. You can see the calcified cartilage pillars with radiating spokes.

 

 

2 hours ago, Al Dente said:

Here is a description of a pristis rostrum describing the placoid scales. Unfortunately the author mixed up the photos with the wrong description for the scales. I think the second photo shows the correct description for the first photo. The paper is "The Identification, Structure, Care, and Conservation of Sawfish Rostra (Rhinopristiformes: Pristidae)" Jessica Byler.

 

 

Eric

 

I think you are correct.  The literature is really confusing.  The translation in the Casier diagram is "The outerlayer".  But thinking about a fossil specimen I could see the placoid scales and skin being gone with the cartilage remaining as the outerlayer.  I see lots of cartilage and fully agree that cartilage would match his diagram. I wonder why Casier got into this baluster discussion and didn't just say there is cartilage below the skin.  You can definitely see the cartilage below the skin in my basal picture of this rostrum.

 

The interesting fact about the placoid scales is I've read a number of papers/books and checked out a number of websites and never saw any discussion on placoid scales on sawfish rostrums.  Your misidentified picture is the first picture that I've seen of the placoid scales on sawfish.  However, the other caption referenced a number of papers that I need to check out.

 

The surface of that Anoxypristis rostrum sure looked similar to the surface of this Pristis rostrum.  However what you posted above says that the underlying cartilage structure has both mineralized and non mineralized areas.  But the cartilage would be below the skin.  So what was on the Anoxypristris rostrum must be placoid scales also?  What do you think?

 

Thanks for pointing this out.  I'll edit this and my other rostrum posts and delete the Casier diagram and just call them placoid scales.

 

Marco Sr.

[Al Dente]

19 minutes ago, MarcoSr said:

So what was on the Anoxypristris rostrum must be placoid scales also?  What do you think?

I think they are also placoid scales.

[MarcoSr]

18 hours ago, Tidgy's Dad said:

Thanks Marco Sr. 

Another great post. 

 

15 hours ago, ynot said:

Thanks again Marco!

 

I corrected the above post per comments from Eric.  So I learn a lot doing these posts.  Also I hope folks here on TFF can see that the literature on extant species can be really confusing and sometimes contradictory.  Hopefully, I've gotten this right now.  At least I take decent pictures.

 

Marco Sr.

[MarcoSr]

2 minutes ago, Al Dente said:

I think they are also placoid scales.

 

Eric

 

I had actually sent pictures of the placoid scales on the Anoxypristis rostrum to several shark researchers and they could not tell me what they were.  After your post I finally understand what I'm seeing and it makes sense.

 

Marco Sr.

[old bones]

Illuminating topic! Thanks to @MarcoSr and @Al Dente

[MarcoSr]

3 hours ago, old bones said:

Illuminating topic! Thanks to @MarcoSr and @Al Dente

 

Julianna

 

Illuminating to me also. 

 

Marco Sr.

[Coco]

I think I have a Pristis pristis rostrum. Do you think I am right ?

 

 

Coco

[MarcoSr]

5 hours ago, Coco said:

I think I have a Pristis pristis rostrum. Do you think I am right ?

 

 

Coco

 

Coco

 

Really nice rostrum.  Based upon the number of rostral teeth alone, 17/16, I would say Pristis pristis.  That number of rostral teeth is below the rostral teeth number range of the other three Pristis species.  Anoxypristis cuspidata can be as low as 16 rostral teeth per rostrum side but your rostral teeth features, placement of your rostral teeth along the rostrum, and your rostrum width doesn't match Anoxypristis cuspidata at all.

 

If you can give me the four measurements (in millimeters is preferred) for SRL, RWP, ISA, ISP,. I can tell you with 100% certainty.  See the picture and the descriptions below.

 

 

 

 

 

Standard Rostral Length (SRL) –rostrum length from the anterior tip to posterior edge of posterior most rostral teeth.

 

Rostral Width Posterior (RWP) –rostrum width at the posterior edge of posterior most rostral teeth.

 

Inter-tooth Space Anterior (ISA)-distance between the posterior edge of the first rostral tooth and the anterior edge of the second rostral tooth.

 

Inter-tooth space posterior (ISP) - distance between the anterior edge of the last rostral tooth and the posterior edge of the next to last tooth.

 

Marco Sr.

[Coco]

SRL = 515 mm

 

RWP = 102 mm

 

ISA = 21 mm

 

ISP =36 mm

 

Thanks for your help Marco

 

Coco

[MrBones]

Found a rostrum fossil last year

[MarcoSr]

5 hours ago, Coco said:

SRL = 515 mm

 

RWP = 102 mm

 

ISA = 21 mm

 

ISP =36 mm

 

Thanks for your help Marco

 

Coco

 

Coco

 

Definitely a Pristis pristis rostrum.

 

Marco Sr.

[MarcoSr]

4 hours ago, MrBones said:

Found a rostrum fossil last year

 

Fossil sawfish rostrums are really rare.  Do you have any pictures that show the ends of your specimen that you could post?  Do you have any close-up pictures to see if there are any placoid scales and to better show the cartilage pattern?

 

Marco Sr.

[MrBones]

I am on vacation now, have some photos of the ends, but no close ups. I will post close ups in 2 weeks once I return

PS. Found in UAE

[MrBones]

[MarcoSr]

4 hours ago, MrBones said:

 

Thank you for the picture.  I'm not sure of the age of your fossil, but fossils from the family Pristidae are found from the Lower Eocene, Ypresian to recent times.  The number of canals/ducts in the rostrum (your specimen looks like it has a median canal and two neural ducts), is used to distinguish between the two extant genera in the family, Pristis and Anoxypristis.  The below excerpt is from Cappetta 2012:

 

 

 

EDIT:  I should have mentioned also the genus Propristis which was from the Middle Eocene, Lutetian to possibly the Miocene.  Below is another excerpt from Cappetta 2012:

 

 

 

 

If your fossil is older, there are a good number of other possible genera.

 

Marco Sr.

[MrBones]

Thank you for the analysis, and further id. As I said I will post a close up picture once I am home.

[MrBones]

I finally got some close ups

[MarcoSr]

4 hours ago, MrBones said:

I finally got some close ups

 

Interesting cartilage pattern.  Thank you for posting.

 

Marco Sr.