Plakodermowwa ryba z embrionami

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Dino
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Plakodermowwa ryba z embrionami

Post autor: Dino »

W dzisiejszym Nature:
http://www.nature.com/news/2008/080528/ ... 3575a.html

Obrazek
Live birth in the Devonian period
John A. Long, Kate Trinajstic, Gavin C. Young & Tim Senden

Abstract

The extinct placoderm fishes were the dominant group of vertebrates throughout the Middle Palaeozoic era1, yet controversy about their relationships within the gnathostomes (jawed vertebrates) is partly due to different interpretations of their reproductive biology. Here we document the oldest record of a live-bearing vertebrate in a new ptyctodontid placoderm, Materpiscis attenboroughi gen. et sp. nov., from the Late Devonian Gogo Formation of Australia (approximately 380 million years ago). The new specimen, remarkably preserved in three dimensions, contains a single, intra-uterine embryo connected by a permineralized umbilical cord. An amorphous crystalline mass near the umbilical cord possibly represents the recrystallized yolk sac. Another ptyctodont from the Gogo Formation, Austroptyctodus gardineri, also shows three small embryos inside it in the same position. Ptyctodontids have already provided the oldest definite evidence for vertebrate copulation, and the new specimens confirm that some placoderms had a remarkably advanced reproductive biology, comparable to that of some modern sharks and rays. The new discovery points to internal fertilization and viviparity in vertebrates as originating earliest within placoderms.

Sue
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Post autor: Sue »

To nieslychanie ciekawe znalezisko, bo nikt nie spodziewal sie, ze rybie pepowiny istnialy tak dawno.
Na stronie http://news.nationalgeographic.com/news ... 91509.html
znajduje sie swietna wizualizacja takiego polaczenia malucha z rybia mama, odtworzonego na podstawie tej skamieliny.

Rybka nie jest duza - ok 25cm. Jak widac w abstrakcie zostala nazwana
Materpiscis attenboroughi, na cześć Davida Attenborough.

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