Extant Pristis pectinata (Smalltooth Sawfish) rostrum

[MarcoSr]

A post by @ynot 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.  I borrowed a Pristis pectinata (Smalltooth Sawfish) rostrum from a friend so I could take pictures of it.  This rostrum is from a sawfish caught off of the West coast of South Florida many years ago.

 

If you would also like to see pictures of an Anoxypristis cuspidata rostrum check out my previous TFF post at the link below:

 

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

 

A  Pristis pectinata rostrum is 21-30 % of total sawfish length.  Pristis pectinata reach a total length of at least 554 cm with reports of 760 cm total length likely exaggerations.  Last 2016.  This rostrum is 10” long so it is from a juvenile sawfish.  Pristis pectinata rostrums have 20-30 rostral teeth per side.  This rostrum has 25/27 rostral teeth (Note some are damaged and/or missing) and is shown below in dorsal and ventral views:

 

 

The basal view of the rostrum (20 mm by 5 mm) shows placoid scales and a thin layer of skin on the dorsal side and on the ventral side above the cartilage of the rostrum.

 

 

 

 

 

Dorsal side, placoid scales covering the rostrum surface:

 

 

 

Ventral Side, placoid scales covering the rostrum surface:

 

 

 

Edit:  Note I should have stated that these rostral teeth are smooth  without a posterior groove.  That is a rostral tooth trait of young Pristis pectinata sawfish.  I didn't notice this until I just looked at the rostral teeth again after reading that young Pristis pectinata sawfish rostral teeth don't have the posterior groove in Last, White, de Carvalho, Seret, Stehmann, Naylor 2016 Rays of the World.  The below picture shows a first anterior rostral tooth (10 mm) that is smooth without a posterior groove.

 

 

 

 

Below are pictures of 8 different rostral teeth (5 mm to 12 mm vertical height)

 

6 rostral teeth dorsal views:

 

 

2 rostral teeth ventral views:

 

 

Fossil Pristis cf lathami rostral tooth (2.25”) from the Eocene of Virginia for comparison to the extant Pristis teeth:

 

 

Unfortunately now Pristis pectinata is a critically endangered species.  Over fishing has not only drastically reduced their numbers but it has also drastically reduced the size of the largest members of the species.  Populations are now fragmented and this species is considered to be extinct through most of its original range.

 

Marco Sr.

Edited January 17, 2019 by MarcoSr
added note and picture on rostral teeth being smooth without a posterior groove, corrected the discusion and added placoid scales

[ynot]

Very nice dissertation Sir!

Thanks for putting this up.

[MarcoSr]

5 hours ago, ynot said:

Very nice dissertation Sir!

Thanks for putting this up.

 

Tony

 

Hopefully the sawfish conservation efforts worldwide help these critically endangered species to survive and recover.

 

Marco Sr.