''Bandringa'' is an extinct genus of

elasmobranch Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by h ...

known from the Pennsylvanian subperiod of the

Carboniferous period The Carboniferous ( ) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the Permian Period, Ma. It is the fifth and penultimate perio ...

. There is currently a single known species, ''B. rayi'', which constitutes the sole member of the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

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 Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

.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 A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, FMNH PF 5686, is a juvenile individual which was found in an

ironstone Ironstone is a sedimentary rock, either deposited directly as a ferruginous sediment or created by chemical replacement, that contains a substantial proportion of an iron ore compound from which iron (Fe) can be smelted commercially. Not to be c ...

concretion A concretion is a hard and compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes a ...

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'', but the differences between the two were found to be taphonomic 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 heaps from Five Points coal mines near Conesville, Ohio and Cannelton, Pennsylvania, both of which contain rocks of the Kittaning Formation of the

Allegheny Group The Allegheny Group, often termed the Allegheny Formation, is a Pennsylvanian (geology), Pennsylvanian-age geological unit in the Appalachian Plateau. It is a major coal-bearing unit in the eastern United States, extending through western and cen ...

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 Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin ...

fish family

Polyodontidae Paddlefish (family Polyodontidae) are a family of ray-finned fish belonging to order Acipenseriformes, and one of two living groups of the order alongside sturgeons (Acipenseridae). They are distinguished from other fish by their elongated rost ...

(

Acipenseriformes Acipenseriformes is an order (biology), order of basal (phylogenetics), basal Actinopterygii, ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct family (biology), families C ...

). The body of ''Bandringa'' had two dorsal fins, a set of three anal fins (5 in total) and a long tapering Heterocercal

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. ''Bandringa'' had a long rostrum and may have been analogous to modern

sawfish Sawfish, also known as carpenter sharks, are a family of very large rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the lar ...

. 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

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s. 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 Ctenacanthiformes is an extinct order of cartilaginous fish. They possessed ornamented fin spines at the front of their dorsal fins and cladodont-type dentition, that is typically of a grasping morphology, though some taxa developed cutting and g ...

, 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 Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...

, 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

where ''Bandringa'' specimens have been found was a diagonally running stream that ran from freshwater to saltwater areas.

References

{{Taxonbar, from=Q21224110 Elasmobranchii Monotypic prehistoric cartilaginous fish genera Fossil taxa described in 1969