BEIJING, May 29 (Xinhuanet) -- A study published Thursday in the British journal Nature said the oldest soon-to-be mother fish has been found in a fossil in northwestern Australia.

    The armored fish was immortalized in a fossil while still attached to her offspring by an umbilical cord, revealing the one last look of the 380-million-year-old mother-to-be.

    "When I first saw the embryo inside the mother fish, my jaw dropped," said researcher John Long, a paleontologist at Museum Victoria in Melbourne, Australia. "It dawned on me after studying the specimen that this was the earliest evidence of vertebrates having sex by copulation — not just spawning in water, but sex that was fun."

    The fish, an entirely new species called "Materpiscis attenboroughi," pushes back the first known case of live birth in the animal kingdom by some 200 million years.

    The tail-first birthing process was probably similar to that of some species of sharks and rays living today, the study says.

    "The discovery is certainly one of the most extraordinary fossil finds ever made, and changes our understanding of the evolution of vertebrates," Long commented.

    During an expedition funded by the Australian Research Council, Long and his colleagues discovered the fish remains buried in the Gogo Formation, a renowned treasure trove of well-pr