Bandringa is an extinct genus of Elasmobranchii known from the Pennsylvanian subperiod of the Carboniferous. There is currently a single known species, B. rayi, which constitutes the sole member of the Monotypic taxon family Bandringidae. The genus was described in 1969 by paleontologist Rainer Zangerl, and is known from exceptionally preserved individuals found in the Mazon Creek Lagerstätte of Illinois.[R. Zangerl. (1969). Bandringa rayi: A New Ctenacanthoid Shark form the Pennsylvanian Essex Fauna of Illinois. Fieldiana Geology 12:157-169]
Discovery and naming
The
holotype specimen,
FMNH PF 5686, is a juvenile individual which was found in an
ironstone concretion in
Illinois during the summer of 1967. This specimen was found by Ray Bandringa, to whom the genus and species owe their name. By 1979, two species from this genus were described,
B. rayi and
B. herdinae,
[R. Zangerl. (1979). New Chondrichthyes from the Mazon Creek fauna (Pennsylvanian) of Illinois. Mazon Creek Fossils 449-500] but the differences between the two were found to be
Taphonomy in origin. All Mazon Creek individuals appear to represent juveniles, suggesting the area was a nursery for them. Also supporting this notion are fossilized egg cases found in the same localities, though it is unclear whether they belong to this genus. Adult fossils attributed to
B. rayi have also been found in
Spoil tip from Five Points coal mines near Conesville, Ohio and Cannelton, Pennsylvania, both of which contain rocks of the Kittaning Formation of the Allegheny Group which were roughly contemporaneous with the Mazon Creek deposits. This material includes a partial skull and complete rostrum which are roughly 16 cm (6.2 in) in length.
Description
Bandringa was a unique looking fish. The most noticeable part of this elasmobranch is its very long snout, which made up half of its body
The snout looks similar to that seen in the unrelated
actinopterygian fish family
Paddlefish (
Acipenseriformes). The body of
Bandringa had two dorsal fins, a set of three anal fins (5 in total) and a long tapering Heterocercal
Fish fin.
Bandringa had a long rostrum and may have been analogous to modern
sawfish. It appears to have fed via suction feeding, and used its long snout and needle like spines on its cheek for hunting in murky water.
Preserved gut contents include articulated
. The holotype specimen is around in total length,
but the largest known adult specimen, PU19814
is estimated to be more than five times larger than the holotype.
While
Bandringa was originally described as an aberrant member of the order Ctenacanthiformes,
its relationships to other elasmobranchs is currently unclear.
Breeding
Bandringa is one of the few fossil fish that has a well studied breeding cycle. Sallan and coauthors in 2014 found that the fish lived a lifestyle that was the opposite of
salmon, with the adults living in freshwater areas and the younger ones living in more brackish and saltwater areas, and when fully grown would swim back into the freshwater areas.
This makes sense because at the time, the area of Illinois where
Bandringa specimens have been found was a diagonally running stream that ran from freshwater to saltwater areas.
