Species delineation and global population structure of Critically Endangered sawfishes (Pristidae)

Abstract

Sawfishes are among the most endangered of all elasmobranch species, a factor fostering considerable worldwide interest in the conservation of these animals. However, conservation efforts have been hampered by the confusing taxonomy of the group and the poor state of knowledge about the family's geographical population structure. Based on historical taxonomy, external morphology, and mitochondrial DNA sequences (NADH-2), we show here that, globally, the sawfish comprise five species in two genera: Pristis pristis (circumtropical), Pristis clavata (east Indo-West Pacific), Pristis pectinata (Atlantic), Pristis zijsron (Indo-West Pacific), and Anoxypristis cuspidata (Indo-West Pacific, except for East Africa and the Red Sea). This improved understanding will have implications for the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), International Union for Conservation of Nature (IUCN) Red List assessments, and endangered species laws and regulations in several countries. Furthermore, based on both or either of NADH-2 and the number of rostral teeth per side, we show that populations of P. pristis, P. pectinata, P. zijsron, and A. cuspidata exhibit significant geographic structuring across their respective ranges, meaning that regional-level conservation will be required. Finally, the NADH-2 gene may serve as a marker for the identification of rostra and fins involved in illegal trade.

The Largetooth Sawfish, Pristis pristis (Linnaeus, 1758), is not extirpated from Peru: new records from Tumbes

“…Following Faria et al (2013), who included P. pristis from Peru based on previous works listing the species in Peruvian waters, subsequent scientific and technical publications also listed this species from Peru but without more precise distributional data and cited it as a historical distribution given the absence of confirmed records for more than 10 years. As a result, many researchers believed that the species had been extirpated from Peru (Carlson et al 2013a, Dulvy et al 2014, Harrison and Dulvy 2014.…”

“…Pristis pristis is morphologically characterized by the first dorsal fin located in front of the origin of the pelvic fins, the presence, in all stages of growth, of the lower lobe of the caudal fin, and by having a shorter and wider rostrum than the other species of Pristis (Faria et al 2013). Recent studies have shown that P. perotteti from the Atlantic Ocean and P. microdon from the western Indo-Pacific Ocean are synonyms of P. pristis.…”

“…Recent studies have shown that P. perotteti from the Atlantic Ocean and P. microdon from the western Indo-Pacific Ocean are synonyms of P. pristis. This eurohaline species, as currently defined, has a circumtropical geographic distribution with 4 genetically differentiated populations: eastern Pacific, western Atlantic, eastern Atlantic, and western Indo-Pacific Ocean (Faria et al 2013).…”

“…The genus Anoxypristis only has 1 species: the Knifetooth Sawfish, Anoxypristis cuspidata (Latham, 1794); the genus Pristis includes 4 species: Largetooth Sawfish, Pristis pristis (Linnaeus, 1758); Smalltooth Sawfish, Pristis pectinata Latham, 1794; Dwarf Sawfish, Pristis clavata Garman, 1906); and Green Sawfish, Pristis zijsron Bleeker, 1851 (Faria et al 2013).…”

What Is the Fate of Amputee Sawfish?

“…There are five extant species of sawfish, all of which possess an enlarged, tooth-lined rostrum (or "saw"), which has unfortunately been central to their widespread global decline, due to the saw rendering them extremely susceptible to net entanglement (Faria et al 2013;Dulvy et al 2014;Whitty et al 2014). Individuals may suffer mortality during entanglement or be euthanized or desawed prior to net removal for either operator safety or to simplify removal of the sawfish from the net.…”