A Brief Review of the Fossil Record of the Pristids and Sclerorhynchids
Jason C. Seitz © 2014
All sawfishes are highly modified and elongate rays that swim like a shark and have a long snout with laterally-placed spines. The snout (called a ‘rostrum’) is actually an extension of the skull (known as the ‘chondrocranium’). The lateral spines of pristid sawfishes are called ‘rostral teeth’ by scientists but the similar spines along the rostrum of Cretaceous sawfishes are called 'rostral spines' by scientists. Like the rest of the skeleton of the sawfish, the rostrum is composed of cartilage, albeit reinforced with extra calcium. The rostrum and rostral teeth are used in food gathering. The sawfish uses the rostrum to stun prey, such as fishes and invertebrates, which it then sucks into its mouth positioned under the head. There is no cutting or tearing and sawfish can only consume fish and invertebrates that fit into the mouth whole.
The modern sawfish group (family Pristidae) first showed up in the fossil record between the beginning of the Cenozoic (about 66 million years ago) and the beginning of the Eocene (about 56 million years ago). The only exception is the nominal genus Peyeria, which first appeared during the upper Cretaceous (about 100 million years ago). However, the fossil material attributed to the genus Peyeria more likely represents another type of ray—a member of the bowmouth guitarfish family (Rhinidae) such as the bowmouth guitarfish (Rhina ancylostoma).
Living (extant) sawfishes include the following species:
The Knifetooth complex (one species):
Prior to the pristids, a diverse group of sawfishes (family Sclerorhynchidae) lived during the Cretaceous epoch. Sclerorhynchids had a diverse array of rostral tooth morphologies, ranging from closely-spaced thin spines to widely-spaced massive barbed spines on sturdy, widened bases. Although most species reached a modest size of about 1 meter in total length, fossil rostra measuring well over 1 meter in length have been unearthed in Cretaceous sediments of Morocco.
There are at least 20 genera of sclerorhynchids, including the following:
Pristids and sclerorhynchids evolved independently from the guitarfishes (Rhinobatidae). Thus, while both groups are commonly referred to as sawfish, and both share similar morphological characteristics, they are not closely related. Sawfishes should not be confused with the saw sharks (family Pristiophoridae), which are true sharks and therefore only distantly related to the sawfishes (which are rays, not sharks).
The rostral spines of sclerorhynchids were attached to the dermis of the rostrum via connective tissue. Their rostral spines are thought to have been continually replaced throughout the life of the animal in the same conveyer-belt fashion as are the oral teeth of all sharks and rays. In contrast, modern pristids have rostral teeth firmly embedded in sockets (called ‘alveoli’) and their teeth are not replaced if lost. Sclerorhynchid rostral spines are covered with an enamel-like coating along the cusp; this coating is lacking in modern pristids. Sclerorhynchids also differ from modern pristids in that they possessed a long, whip-like caudal fin. Although the average fossil remains consist of isolated rostral spines or oral teeth, some beautiful and fully articulated fossil skeletons have been unearthed in Lebanon quarries.
Sources
Alroy, J. and M. McClennen. 2013. Paleobiology Database [online resource]. Accessed 06/10/13 online at http://www.paleodb.org/?a=displaySearchColls&.
Faria, V.V., M.T. McDavitt, P. Charvet, T.R. Wiley, C.A. Simpfendorfer, and G.J.P. Naylor. 2013. Species delineation and global population structure of critically endangered sawfishes (Pristidae). Zoological Journal of the Linnean Society 167(1):136–164.
Farrés, F. 2003. Mesopristis nov. gen. osonensis nov. sp., nueyo genero y especie de pez-sierra del Eocene de Vic, (Catalunya, NE. de Espana). Batalleria 11:93–113. PDF
Wueringer, B.E., L. Squire Jr., and S.P. Collin. 2009. The biology of extinct and extant sawfish (Batoidea: Sclerorhynchidae and Pristidae). Reviews in Fish Biology and Fisheries 19:445–464.
The modern sawfish group (family Pristidae) first showed up in the fossil record between the beginning of the Cenozoic (about 66 million years ago) and the beginning of the Eocene (about 56 million years ago). The only exception is the nominal genus Peyeria, which first appeared during the upper Cretaceous (about 100 million years ago). However, the fossil material attributed to the genus Peyeria more likely represents another type of ray—a member of the bowmouth guitarfish family (Rhinidae) such as the bowmouth guitarfish (Rhina ancylostoma).
Living (extant) sawfishes include the following species:
The Knifetooth complex (one species):
- Anoxypristis cuspidata (knifetooth sawfish [western Pacific and Indian oceans])
- Pristis clavata (dwarf sawfish [western Pacific Ocean])
- Pristis pectinata (smalltooth sawfish [eastern and western Atlantic Ocean])
- Pristis zijsron (green sawfish [western Pacific and Indian oceans])
- Pristis pristis (largetooth sawfish [eastern and western Atlantic, eastern and western Pacific, and Indian oceans])
- Anoxypristis spp. (fossils of Europe, North America, West and East Africa)
- Mesopristis osonensis (probably a junior synonym of Anoxypristis; described from fossils of Catalonia in northeastern Spain)
- Peyeria libyca (nominal species; fossils of northeast Africa including Egypt)
- Propristis schweinfurthi (fossils of North and West Africa)
- Pristis spp. (at least eight extinct species described; fossils of West and East Africa, Europe, and North America)
Prior to the pristids, a diverse group of sawfishes (family Sclerorhynchidae) lived during the Cretaceous epoch. Sclerorhynchids had a diverse array of rostral tooth morphologies, ranging from closely-spaced thin spines to widely-spaced massive barbed spines on sturdy, widened bases. Although most species reached a modest size of about 1 meter in total length, fossil rostra measuring well over 1 meter in length have been unearthed in Cretaceous sediments of Morocco.
There are at least 20 genera of sclerorhynchids, including the following:
- Ankistrorhynchus (fossils of Europe and North America)
- Atlanticopristis (fossils of South America)
- Baharipristis (fossils of East Africa)
- Biropristis (fossils of South America)
- Borodinopristis (a nominal genus of about three species [fossils of North America])
- Ctenopristis (fossils of West and East Africa)
- Dalpiaza (fossils of West Africa)
- Ganopristis (fossils of Europe)
- Ischyrhiza (fossils of North and South America)
- Kiestus (fossils of North America)
- Libanopristis (fossils of Middle East)
- Marckgrafia (fossils of West Africa)
- Micropristis (fossils of Europe and Middle East)
- Onchopristis (fossils of North America, Europe, West and East Africa, Asia, New Zealand)
- Onchosaurus (fossils of North America and West Africa)
- Plicatopristis (fossils of the Middle East)
- Pucapristis (fossils of South America)
- Renpetia (fossils of the Middle East)
- Schizorhiza (fossils of North America and Middle East)
- Sclerorhynchus (fossils of North America and Middle East)
Pristids and sclerorhynchids evolved independently from the guitarfishes (Rhinobatidae). Thus, while both groups are commonly referred to as sawfish, and both share similar morphological characteristics, they are not closely related. Sawfishes should not be confused with the saw sharks (family Pristiophoridae), which are true sharks and therefore only distantly related to the sawfishes (which are rays, not sharks).
The rostral spines of sclerorhynchids were attached to the dermis of the rostrum via connective tissue. Their rostral spines are thought to have been continually replaced throughout the life of the animal in the same conveyer-belt fashion as are the oral teeth of all sharks and rays. In contrast, modern pristids have rostral teeth firmly embedded in sockets (called ‘alveoli’) and their teeth are not replaced if lost. Sclerorhynchid rostral spines are covered with an enamel-like coating along the cusp; this coating is lacking in modern pristids. Sclerorhynchids also differ from modern pristids in that they possessed a long, whip-like caudal fin. Although the average fossil remains consist of isolated rostral spines or oral teeth, some beautiful and fully articulated fossil skeletons have been unearthed in Lebanon quarries.
Sources
Alroy, J. and M. McClennen. 2013. Paleobiology Database [online resource]. Accessed 06/10/13 online at http://www.paleodb.org/?a=displaySearchColls&.
Faria, V.V., M.T. McDavitt, P. Charvet, T.R. Wiley, C.A. Simpfendorfer, and G.J.P. Naylor. 2013. Species delineation and global population structure of critically endangered sawfishes (Pristidae). Zoological Journal of the Linnean Society 167(1):136–164.
Farrés, F. 2003. Mesopristis nov. gen. osonensis nov. sp., nueyo genero y especie de pez-sierra del Eocene de Vic, (Catalunya, NE. de Espana). Batalleria 11:93–113. PDF
Wueringer, B.E., L. Squire Jr., and S.P. Collin. 2009. The biology of extinct and extant sawfish (Batoidea: Sclerorhynchidae and Pristidae). Reviews in Fish Biology and Fisheries 19:445–464.