The sawfishes are large (commonly reaching 5 m reported to 7+ m1), bottom dwelling batoids that are best characterized by their saw-like rostrums. Although they may appear more shark than ray-like, the trunk and (particularly) head are flattened ventrally and various morphological characteristics clearly make them batoids.
Found circumglobally in tropical and subtropical coastlines & rivers, these fishes prefer shallow waters with sandy or muddy bottoms. An inshore taxa, they are seldom reported from below 5 or 6 fathoms. They are most plentiful in shallow bays and estuaries, and can be found in fresh water (i.e., lower Mississippi, Amazon & Lake Nicaragua). Sawfishes feed on small schooling fish and invertebrates, using their specialized rostrums to probe in the sand or slash and stun fishes.
Compagno (1999) includes seven extant species in two genera.
Pristis LINCK 1790 includes:
P. clavata GARMAN 1906 [Australia],
P. microdon LATHAM 1794 [Indian Ocean & western Pacific Oceans],
P. pectinata LATHAM 1794< [Atlantic, Pacific and Indian Oceans],
P. perotteti VALENCIENNES in MÜLLER & HENLE 1841 [Eastern & Western Atlantic,
Eastern Pacific, Indian Ocean],
P. pristis (LINNAEUS, 1758) [Eastern Atlantic & Mediterranean] and
P. zijsron BLEEKER 1851 (No Indian Ocean & western Pacific Oceans].
Anoxypristis WHITE & MOY-THOMAS 1941 is represented by a single species,
A. cuspidata (LATHAM, 1794) [No Indian Ocean & western Pacific Oceans].
The "saw" itself is an elongated rostral projection from the cranium, bearing on each side, a single series of large tooth-like structures. The cartilage encloses 3-5 longitudinal canals or ducts and is strengthened by calcification. The rostral teeth are embedded in deep sockets (alveoli) of this hardened cartilage.
Bigelow & Schroeder (1953) note that the number of rostral teeth is determined before birth, and varies in number between and within species. The Common sawfish (Pristis pectinata) has 25-32 pairs and the Southern sawfish (P. perotteti) 16-19 pairs. Unlike true (oral) teeth that attain their final size before becoming functional (and later being shed), these specialized dermal denticles have continually growing bases. The rostral teeth are slightly recurved, dorso-ventrally compressed, have a flattened posterior edge and slightly striate base.
These authors note that in P. pectinata, the saw is roughly 1/4 the overall length of the fish, 1/7 as broad as long, and 1/5 as thick as broad (elongated and flattened). The rostral teeth are short and broad at the base (1.5:1) and narrower and longer at the tip (4:1). The anterior edge is sharp and the posterior flat. Towards the tip, the teeth are channeled longitudinally. Oral teeth are minute, dome-shaped with an anteriorly positioned transverse cutting edge. The dentition includes 88-128/84-176 files with 10-12 functional rows in each jaw.
In P. perotteti the "saw" is relatively shorter (1/5 total length), broader (1/5-1/6 length) and grows narrower anteriorly. There are fewer rostral teeth (16-19 per side) which are more evenly spaced and sized (4-5 x long as wide). The 5 or 6 most posterior teeth dip downward and the anteriors project horizontally. Interestingly Bigelow & Schroeder (pg 38) note that the anterior edge is sharp but the posterior is flat on smaller and channeled on larger specimens. Compared with pectinata, the oral teeth are larger (1.3- 1.4 mm), more loosely set and in fewer (70-90) files.
Genera page on Fossil Pristids
Rick Martin's Elasmo Heavy Weights
||Based on the examination of 90+ specimens, Matthew McDavitt (pers. com. 2002)
notes that the Smithsonian "has a 1223mm rostrum in their collection, taken from a
largetooth sawfish (either P. microdon or P. perotteti, depending on
capture location, which was unknown according to the tag) with huge rostral teeth.
Based on rostral length, the total length of the animal would have been over
6 meters; the functional portion of the largest rostral tooth (measured from
where it emerges from the rostral body) was 106mm long... The overall length
of the rostral teeth could not be ascertained as the teeth were firmly embedded
in the rostrum. 106mm for the exposed portion of a rostral tooth alone is
certainly the largest I have personally encountered, extant or fossil."