New discoveries on Devonian fossil fish

Eastmanosteus calliaspisFrom Palaeoblog:

In this paper, we show exceptional three-dimensionally preserved fossilized muscle tissues in 380–384Myr old placoderm fish (Late Devonian), offering new morphological evidence supporting the hypothesis that placoderms are the sister group to all other gnathostomes.

We describe the oldest soft tissue discovered in gnathostomes, which includes striated muscle fibres, circulatory and nerve tissues, preserved as phosphatized structures precipitated by microbial infilling of small, protected areas under the headshield of the arthrodire, Eastmanosteus calliaspis.

Muscle impressions have also been found in the ptyctodontid, Austroptyctodus gardineri.

The specimens display primitive vertebrate muscle structures; in particular, shallow W-shaped muscle blocks such as those observed in lampreys.

New information from fossilized soft tissues thus elucidates the affinities of the placoderms and provides new insights into the evolution and radiation of gnathostomes.

See also here.

Brook lampreys on the Veluwe in The Netherlands here.

Fossil fish history, especially in Germany, and coelacanth video: here.

Devonian fossil trees: here.

And here.

And here.

2 thoughts on “New discoveries on Devonian fossil fish

  1. Zanzibar fishermen land ancient fish
    Sun Jul 15, 2007 12:40PM EDT

    ZANZIBAR (Reuters) – Fishermen in Zanzibar have caught a coelacanth, an ancient fish once thought to have become extinct when it disappeared from fossil records 80 million years ago, an official said on Sunday.

    Researcher Nariman Jidawi of Zanzibar’s Institute of Marine Science said the fish was caught off the tropical island’s northern tip.

    “The fishermen informed us they had caught this strange fish and we quickly rushed to find it was a coelacanth,” he told Reuters, adding that it weighed 27 kg (60 lb) and was 1.34 meters long.

    The coelacanth, known from fossil records dating back more than 360 million years, was believed to have become extinct some 80 million years ago until one was caught off the eastern coast of South Africa in 1938 — a major zoological find.

    None has since been caught in South African waters, but around 30 have been caught in recent years off Tanzania, possibly because diminishing shallow-water resources have forced fishermen to cast their nets in the deeper waters where coelacanths live, experts say.

    Coelacanths are the only living animals to have a fully functional intercranial joint, a division separating the ear and brain from the nasal organs and eye.

    © Reuters 2007


  2. Pingback: Devonian era animals and plants | Dear Kitty. Some blog

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