Bonnerichthys
Encyclopedia
Bonnerichthys is a new genus of fossil fish within the family Pachycormidae
that lived during the Late Cretaceous
Period Fossil
remains of this taxon
are known from the Smoky Hill Member
of the Niobrara Chalk Formation of Kansas (Late Coniacian
-Early Campanian
). It grew to around 20 feet in length, though not quite as large as the related Leedsichthys
from the Jurassic
of Europe
which likely grew up to 30 feet.
, living on plankton
. This recognition that many large-bodied fish from the Mesozoic
in the Pachycormidae
were filter feeders shows that this niche
was filled for at least 100 million years before previously known. The modern niche is filled by several species of shark
s and the baleen whale
s.
Pachycormidae
Pachycormidae is an extinct family of ray-finned fish known from Mesozoic deposits from Eurasia and the Americas. They were characterized by having serrated pectoral fins, reduced pelvic fins and a bony rostrum. Certain members of the group were large filter-feeding planktivores...
that lived during the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains of this taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
are known from the Smoky Hill Member
Smoky Hill Chalk
The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous conservation Lagerstätte, or fossil rich geological formation, known primarily for its exceptionally well-preserved marine reptiles. The Smoky Hill Chalk Member is the uppermost of the two structural units of the Niobrara...
of the Niobrara Chalk Formation of Kansas (Late Coniacian
Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...
-Early Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
). It grew to around 20 feet in length, though not quite as large as the related Leedsichthys
Leedsichthys
Leedsichthys was a giant pachycormid that lived in the oceans of the Middle Jurassic period. The closest living relative of the pachycormids is the bowfin, Amia calva, but this is only very distantly related....
from the Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
which likely grew up to 30 feet.
Feeding
One of the most significant features of Bonnerichthys is the recognition that it was a filter feederFilter feeder
Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
, living on plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
. This recognition that many large-bodied fish from the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
in the Pachycormidae
Pachycormidae
Pachycormidae is an extinct family of ray-finned fish known from Mesozoic deposits from Eurasia and the Americas. They were characterized by having serrated pectoral fins, reduced pelvic fins and a bony rostrum. Certain members of the group were large filter-feeding planktivores...
were filter feeders shows that this niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
was filled for at least 100 million years before previously known. The modern niche is filled by several species of shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s and the baleen whale
Baleen whale
The Baleen whales, also called whalebone whales or great whales, form the Mysticeti, one of two suborders of the Cetacea . Baleen whales are characterized by having baleen plates for filtering food from water, rather than having teeth. This distinguishes them from the other suborder of cetaceans,...
s.
External links
- Bonnerichthys at the Oceans of Kansas website. Includes detailed taxonomic history, life restorations, bibliography, many photos of fossil remains.
- Bonnerichthys discussion at boneblogger.com