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Bandriga rayi
#1
Bandriga rayi

[Image: bandringa.jpg]

Scientific Classification
Kingdom:  Animalia
Phylum:  Chordata
Class:  Chondrichthyes
Subclass:  Elasmobranchii
Order: Ctenacanthiformes
Family:  Bandringidae
Genus: Bandriga
Species: Bandriga rayi

[Image: 15345124460_f6f5d346a8_b.jpg]

Bandringa rayi was an unusual looking ancient shark that had a rostrum perhaps half it's body length.  This rostrum was not, in appearance not terribly different from a paddlefish's rostrum.  It was probably used to dig through the sediment in shallow water habitats. 
Bandringa was first named in‭ ‬1969‭ ‬by R.‭ ‬Zangerl with the type species as B.‭ ‬rayi, a freshwater shark that grew to just over a dozen feet long. ‬Then a decade later‭ ‬Zangerl named a second species,‭ b. hudsonae, a much smaller species, only four to six inches and it lived in salt water lagoons. ‬Then in‭ ‬2012‭ ‬a new study by Lauren Cole Sallan and Michael I Coates was penned and published online in‭ ‬2014.
What this study determined was that the B. hudsonae had no adults.  Only young and egg cases.  The different habitats were not necessarily strange.  More than one type of shark over the history of sharks has been able to travel between fresh and salt water.  What was interesting was that what was being found was a shark being anodramous with the eggs and young being saltwater and teh adults fresh. Having nursery grounds are well documented in sharks. C. megalodon seems to have had such behavior.  Fresh to salt water is less common.  The most familiar modern example is with the European eel.  While the eels die after spawning, we do not know if Badringa did the same.  It is possible that they survived, as the adults are not typically found in the spawning grounds as fossils.

[Image: Bandringa_rayi_%282%29.jpg]
[-] The following 1 user Likes ScalesofAnubis's post:
  • Claudiu Constantin Nicolaescu
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#2
According to paleontologists from the University of Chicago and the University of Michigan, long-extinct Bandringa sharks migrated downstream from freshwater swamps to the ocean to spawn in shallow coastal waters and left behind fossil evidence of one of the earliest known shark nurseries.
[Image: image_1678_1-Bandringa-shark.jpg]
The long-snouted Bandringa shark (Elasmobranchii, Chondrichthyes) – a bottom-feeding predator that lived in an ancient river delta system in what is today the Upper Midwest – is likely one of the earliest close relatives of modern sharks.

It resembled present-day sawfish and paddlefish, with a spoon-billed snout up to half its body length. Juveniles were 4 to 6 inches long and grew into adults of up to 10 feet.

Bandringa sharks were discovered in 1969 and soon became one of the most prized fossils from the well-known Mazon Creek deposits in northern Illinois.

Until now, paleontologists believed that the genus Bandringa contained two species – B. rayi and B. herdinae, one that lived in freshwater swamps and rivers and another that lived in the shallow ocean.

But after reevaluating fossils from 24 individuals, Dr Lauren Sallan and Dr Michael Coates concluded that Bandringa was a single species that lived, at various times during its life, in fresh, brackish and salt water.
“The physical differences between the two purported species were due to different preservation processes at marine and freshwater locations. The freshwater sites tended to preserve bones and cartilage, while the marine sites preserved soft tissue,” explained Dr Sallan and Dr Coates, co-authors of the paper published in the Journal of Vertebrate Paleontology.

[Image: image_1678_2-Bandringa-shark.jpg]
By combining the complementary data sets from both types of fossil sites and reclassifying Bandringa as a single species, the team gained a far more complete picture of the extinct shark’s anatomy and discovered several previously unreported features. They include downward-directed jaws ideal for suction-feeding off the bottom, needle-like spines on the head and cheeks, and a complex array of sensory organs on both the extended snout and body, suited for detecting prey in murky water.

The Bandringa fossils also reveal the only known example of a freshwater to saltwater shark migration, as well as a 310-million-year-old shark nursery where fossilized egg cases and juvenile sharks were preserved in the same sediments.

“Adult Bandringa sharks lived exclusively in freshwater swamps and rivers,” the scientists said.
“Females apparently traveled downstream to a tropical coastline to lay their eggs in shallow marine waters, a reverse version of the modern-day salmon’s sea-to-stream migration. At the time, the coastline of the super-continent Pangaea ran diagonally between the Mazon Creek freshwater and marine sites.”



Journal Reference:
Lauren Cole Sallan & Michael I. Coates. 2014. The long-rostrumed elasmobranch Bandringa Zangerl, 1969, and taphonomy within a Carboniferous shark nursery. Journal of Vertebrate Paleontology, vol. 34, no. 1, pp. 22-33; doi: 10.1080/02724634.2013.782875

ABSTRACT
The shark Bandringa (Elasmobranchii, Chondrichthyes), from the Pennsylvanian (Moscovian) Lagerstätte of Mazon Creek, Illinois, is notable for an elongated snout constituting up to half of total body length. This genus formerly contained two distinct species (B. rayi and B. herdinae). However, reexamination of all cataloged material from Mazon Creek and similarly aged North American coal measure localities shows that characteristics previously considered diagnostic at the species level can be attributed to differential taphonomy in adjacent marine and non-marine deposits. We find no evidence of morphologically distinct populations. A monospecific Bandringa exhibiting complementary data sets from localities with different modes of preservation provides a more complete picture of hard- and soft-tissue anatomy than resident taxa from a single deposit. Our new reconstruction of Bandringa incorporates several previously unreported features, including ventrally directed jaws, stellate squamation, a branched lateral line, and fin spines bearing smooth costae. Bandringa occupies an unresolved position within total-group Elasmobranchii, but displays similarities with sphenacanthids, hybodontiforms, and other member clades of the stem group. Bandringa is most simply interpreted as a freshwater, benthic, suction-feeding shark, and as a plausible analogue of modern sawfish (Pristidae). Juveniles of the Carboniferous Bandringa appear to have inhabited one of the earliest known shark nurseries at the brackish and marine Mazon Creek before migrating to freshwaters elsewhere.

https://www.tandfonline.com/doi/abs/10.1...013.782875
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