  New characters based on the arrangement and morphology of dermal denticles
show that sawfishes can be divided into two distinctive groups. The first
group, comprising the knifetooth sawfish Anoxypristis cuspidata, is
characterized by tricuspid denticles variably located on both dorsal and
ventral parts of the body. The second group is represented by species of the
genus Pristis, showing an uniform and homogenous dermal covering of
monocuspidate denticles on both dorsal and ventral sides of the body and within
the buccopharyngeal cavity. Pristis is further divided into two subgroups: the
first comprises species with denticles lacking any keels and furrows (the
smalltooth sawfish Pristis pectinata, the green sawfish Pristis zijsron and the
dwarf sawfish Pristis clavata); the second comprises species with denticles
presenting keels and furrows well differentiated on their anterior part (the
common sawfish Pristis pristis, the largetooth sawfish Pristis perotteti and
the greattooth sawfish Pristis microdon). This investigation of the dermal
covering provides results which agree with studies that separate the same two
species groups of Pristis on the basis of other morphological data.
