Sclerorhynchoidei is an extinct suborder of
rajiform rays that had long
rostra
The Rostra () was a large platform built in the city of Rome that stood during the republican and imperial periods. Speakers would stand on the rostra and face the north side of the Comitium towards the senate house and deliver orations to t ...
with large
denticles similar to
sawfishes and
sawsharks. This feature was
convergently evolved, recently proposed as 'pristification', and their closest living relatives are actually
skates.
While they are often called "sawfishes", sawskates is a more accurate
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...
proposed in 2021 for sclerorhynchoids,
which has been subsequently used by other researchers.
The suborder contains five named families:
Ganopristidae,
Ischyrhizidae,
Onchopristidae,
Ptychotrygonidae, and
Schizorhizidae.
Several genera (see below) are not currently placed in any of these families. Sclerorhynchoids first appeared in the
Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...
and went extinct during the
Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the extinction event, mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event cau ...
, with former
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...
occurrences being misidentifications or
reworked specimens.
One female specimen of ''
Libanopristis'' with nine embryos preserved ''in situ'' represents one of the first fossil evidence of batoid
ovoviviparity
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that r ...
.
Phylogeny
Below is a cladogram of Sclerorhynchoidei, with the topology based on Villalobos-Segura ''et al.'' (2021b) and the family taxonomy based on Greenfield (2021).
Other genera
*†''
Agaleorhynchus''
*†''
Ankistrorhynchus''
*†''
Atlanticopristis''
*†''
Australopristis''
*†''
Baharipristis''
*†''
Biropristis''
*†''
Borodinopristis''
*†''
Celtipristis''
*†''
Columbusia''
*†''
Ctenopristis''
*†''
Dalpiazia''
*†''
Iberotrygon''
*†''
Kiestus''
*†''
Marckgrafia''
*†''
Onchosaurus''
*†''
Plicatopristis''
*†''
Pucapristis''
*†''
Renpetia''
*†
Sao Khua sclerorhynchoid
References
{{Taxonbar, from=Q25095431
Fish suborders