Undated handout photo of Jack Matthews of Oxford University photographing rangeomorph fossils in the rocks at the Mistaken Point Ecological Reserve, on Newfoundland's Avalon Peninsula. Photograph by: Handout , Alex Liu For Randy Boswell

A team of British and Canadian scientists probing a famous fossil site in Newfoundland and Labrador has discovered traces of some of the earliest animal remains on Earth — a 579-million-year-old nest of petrified "babies" born to a primitive, fern-shaped marine organism known as a rangeomorph and then promptly buried in ash from a primordial volcanic eruption.

The discovery, detailed in the latest issue of the U.K.-based Journal of the Geological Society, adds even more scientific lustre to the renowned Mistaken Point Ecological Reserve, a world-class paleontological treasure located about 100 kilometres south of St. John's on the Avalon Peninsula.

The site is a hotbed of fossils from the Ediacaran era of evolution that prevailed from about 640-540 million years ago.

While the later Cambrian era is known for its "explosion" of animal diversity some 500 million years ago — a period typified by the huge number and variety of species seen at B.C.'s Burgess Shale fossil site — the Ediacaran represents a time when relatively few complex organisms existed anywhere on Earth.

But Newfoundland — home to the world's first recorded remains of an Ediacaran species, discovered in a rocky outcrop in St. John's in the 1870s — offers some of the best Ediacaran fossil beds on the planet. And at a place called Pigeon Cove near the island's southernmost tip, the Oxford University-led research team found a "nursery" of juvenile rangeomorphs that died under a "Pompeii-style" deluge of volcanic ash, the scientists state in a summary of their findings.

"The fossilized 'babies' we found are all less than three centimetres long and are often as small as six millimetres; many times smaller than the 'parent' forms, seen in neighbouring areas, which can reach up to two metres in length," said Oxford paleontologist Martin Brasier, who co-authored the study with fellow Oxford scientist Jack Matthews, Cambridge University's Alexander Liu and Duncan McIlroy of the Memorial University of Newfoundland.

"This new discovery comes from the very bottom of the fossil-bearing rocks, making it one of the oldest bedding planes to preserve 'animal' fossils in the whole of the geological record," Brasier added. "We think that, around 579 million years ago, an underwater 'nursery' of baby Ediacaran fronds was overwhelmed, Pompeii-style, by an ash fall from a volcanic eruption on a nearby island that smothered and preserved them for posterity."

The researchers note that the young rangeomorphs frozen in time along Newfoundland's southern shore are difficult to categorize and "where exactly they fit in the tree of life is unclear."

Though such species are believed to have lived in the ocean depths beyond the reach of light — and were thus unlikely to have been plants — they "may not have had all of the characteristics of animals" as we understand them today, the team states.

"These juveniles are exceptionally well preserved, and include species never before found in rocks of this age," noted Liu, the lead author of the paper. "The discovery confirms a remarkable variety of rangeomorph fossil forms so early in their evolutionary history."