New piece in the jigsaw puzzle of human origins

Jan 15, 2009

In an article in today's Nature, Uppsala researcher Martin Brazeau describes the skull and jaws of a fish that lived about 410 million years ago. The study may give important clues to the origin of jawed vertebrates, and thus ultimately our own evolution.

Ptomacanthus anglicus was a very early jawed fish that lived in the Devonian period some 410 million years ago. It represents a type of fossil fish known as an "acanthodian" which is characterized by a somewhat shark-like appearance and sharp spines along the leading edges of all fins (except for the tail fin). This group of early jawed fishes may reveal a great deal about the origin of jawed vertebrates (a story that ultimately includes our own origins). However, their relationships to modern jawed vertebrates (and thus their evolutionary significance) are poorly understood, owing partly to the fact that we know very little about their internal head skeleton.

"To date, we have detailed data from one genus Acanthodes, which occurred very late in acanthodian history", Martin Brazeau says.

"I present details on the morphology of the braincase of Ptomacanthus, which is more than 100 million years older than Acanthodes. It is a radically different morphology from Acanthodes, which has several important implications for the relationships of acanthodians. The braincase of Acanthodes appears to most closely resemble that of early bony vertebrates, the lineage that ultimately includes humans and other land-living vertebrates). For this reason, the acanthodians were thought to share a closer ancestor with bony vertebrates than with sharks. However, the braincase of Ptomacanthus more closely resembles that of early shark-like fishes, and shares very few features in common with Acanthodes and the bony vertebrates."

"As a consequence, the results indicate that Ptomacanthus was either a very early relative of sharks, or close to the common ancestry of all modern jawed vertebrates."

Source: Uppsala University

Explore further: New search planned for grave of Spanish poet Lorca

add to favorites email to friend print save as pdf

Related Stories

'Jaws' lived in Doncaster according to fossil record

Sep 15, 2014

(Phys.org) —Sharks, swamps and a tropical rainforest teeming with life – it's not what comes to mind when you think of Yorkshire. But for the first time evidence of Doncaster's 310-million-year-old past, ...

Life on Earth still favours evolution over creationism

Sep 11, 2014

Charles Darwin's Theory of Evolution, first published in 1859, offered a bold new explanation for how animals and plants diversified and still serves as the foundation underpinning all medical and biological ...

Recommended for you

New search planned for grave of Spanish poet Lorca

20 hours ago

Archeologists will start inspecting land in southern Spain near where the acclaimed poet Federico Garcia Lorca is believed to have been executed and buried at the start of the Spanish Civil War in 1936, officials said Friday.

Seeing dinosaur feathers in a new light

Oct 30, 2014

Why were dinosaurs covered in a cloak of feathers long before the early bird species Archaeopteryx first attempted flight? Researchers from the University of Bonn and the University of Göttingen attempt ...

Mexico archaeologists explore Teotihuacan tunnel (Update)

Oct 29, 2014

A yearslong exploration of a tunnel sealed almost 2,000 years ago at the ancient city of Teotihuacan yielded thousands of relics and the discovery of three chambers that could hold more important finds, Mexican ...

Peruvian dig reveals sacrificial mystery

Oct 29, 2014

Tulane University physical anthropologist John Verano has spent summers in Peru for the last 30 years, digging for ancient bones and solving their secrets. But his most recent work focuses on a unique archeological ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

mabarker
1 / 5 (1) Jul 14, 2009
This article says in classic evolutionary style, *The study may give important clues to the origin of jawed vertebrates, and thus ultimately our own evolution.*

Give me a break.

Herewith are the facts: the Agnatha (jawless fish) such as the lamprey (Petromyzontida) are quite complex in their design (e.g. well-formed eyes, filter feeding ability) and are genuine fish. Looking to the fossil record for their evolutionary ancestors has revealed nothing. M. Benton (2005) is cautious, saying, *Lampreys and hagfishes are very different from many of the extinct jawless fishes, but they are unique in perhaps showing us something of the Early Paleozoic world, before jaws existed* [emphasis mabarker] p. 44

Three darwinists stated, . . . no forms intermediate between agnathans [vertebrates containing the earliest and most primitive vertebrates] and gnathostomes [jawed vertebrates including the fishes] are known. Hickman, et al. 1997, p. 501

*The evolutionary relationships of gnathostomes [jawed vertebrates] have been the subject of study for almost a century. Fossils, morphological characters, and molecular sequences have been used to infer their phylogenetic relationships. However, these studies have proposed different models of relationships that have not been resolved with confidence. Phylogenetic analysis of mitochondrial and some nuclear gene sequences have generated conflicting models, indicating that molecular sequences may not be adequate for resolving the deep branches of gnathostomes* Venkatesh, Erdmann and Brenner, PNAS 2001.
Ethelred
5 / 5 (1) Jul 15, 2009

Herewith are the facts: the Agnatha (jawless fish) such as the lamprey (Petromyzontida) are quite complex in their design (e.g. well-formed eyes, filter feeding ability) and are genuine fish.


And have undergone another 410 million years of evolution.

Looking to the fossil record for their evolutionary ancestors has revealed nothing


Sure it has. If it hadn't you wouldn't be mining for quotes to try to make reality go away.

Three darwinists stated, . . . no forms intermediate between agnathans [vertebrates containing the earliest and most primitive vertebrates] and gnathostomes [jawed vertebrates including the fishes] are known. Hickman, et al. 1997, p. 501


Well that has now changed. So much for searching and quoting but not reading.

You really should the sources of your out of context quotes.

Ethelred

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.