Fossils of this oddball fish were recently discovered by scientists in Colorado, News.com.au reports. The re-examination of fossils from another species, discovered in Japan, meant that there were now three species of this genus known to science, and this has greatly widened the paleocritter’s geographical range.
Prior to this discovery, the only Rhinconichthys fossils had been found in England.
Paleobiologist Kenshu Shimada, of DePaul University, in Chicago, is one of the authors of a study on this new species, noted that Rhinconichthys are extremely rare. The two new species have been dubbed R. purgatoirensis and R. uyenoi.
The study will be published in the journal Cretaceous Research.
He was part of a team that named Rhinconichthys in 2010, and it was based on the single species from England, Sci-News.com reported. The team, he said, “had no idea back then that the genus was so diverse and so globally distributed.”
Rhinconichthys belongs to the pachycormidae, an extinct group of bony fish. Some members of this group, like Leedsichthys problematicus, grew huge. As science writer Brian Switek notes in National Geographic, this majestic monster swam the Jurassic seas of 165 million years ago. Estimates say Leedsichthys reached lengths of 26 to 55 feet.
Rhinconichthys is estimated to be smaller, with R. uyenoi pegged at between 11 and 15 feet, and R. purgatoirensis pegged at 6.5 to 9 feet, Sci-News reports.
Roaming the Cretaceous seas of North America and Japan, R. purgatoirensis and R. uyenoi lived about 92 million years ago. They were well-equipped for feeding on plankton, having prominent, elongated bones called hyomandibulae.
This feature is considered to be a key functional specialization that is crucial to the biology of Rhinconichthys, the scientists noted.
“One pair of hyomandibulae formed a massive oar-shaped lever to protrude and swing the jaws open extra wide, like a parachute, in order to receive more plankton-rich water into its mouth,” Shimada said.
A diet based on plankton is also known as suspension-feeding, and several species of aquatic animals practice this today, including the Blue Whale, Manta Ray, and Whale Shark, DePaul University noted in a statement. But suspension-feeding in the age of dinosaurs is a new area of research.
“Based on our new study, we now have three different species of Rhinconichthys from three separate regions of the globe, each represented by a single skull,” Shimada said. “This tells just how little we still know about the biodiversity of organisms through the Earth’s history. It’s really mind-boggling.”
Since Tuesday, Feb. 12 is the anniversary of Charles Darwin’s birth, this fascinating discovery comes at a most appropriate time. In his book, On The Origin of Species, the noted naturalist wrote:
“There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”
Indeed.
