Scientists just solved a 160-million-year fossil mystery “I’ve never seen anything like it”

A 550-million-year-old soft-bodied sponge fossil fills a critical gap in the evolutionary record, forcing a rethink of how to trace the dawn of animal life. | Contesto: cronaca

Punti chiave

• Scientists just solved a 160-million-year fossil mystery “I’ve never seen anything like it”

Contesto

A team of scientists has solved a paleontological puzzle spanning 160 million years with the discovery of a 550-million-year-old fossil sponge that fundamentally alters the search for the earliest animal life. The exceptionally preserved specimen, unearthed from geological formations in China, represents a primitive sponge that lacked the hard, mineralized skeletal parts typical of its later relatives. This critical absence explains a notorious gap in the fossil record, a period often called the "missing years" of early sponge evolution, where evidence for these foundational creatures had virtually disappeared. The fossil, described in a new study, provides the first tangible evidence supporting a long-held hypothesis: the very first sponges were soft-bodied organisms. Without the robust spicules—tiny, needle-like structures of silica or calcium carbonate that form the skeletons of modern sponges—these ancient lifeforms were far less likely to be preserved under normal conditions. "I've never seen anything like it," said one researcher involved in the analysis, noting the fossil's unique cellular and anatomical detail. Its preservation in such fine sediment offers a rare snapshot of a creature that would typically vanish without a trace. This discovery directly addresses a paradox at the heart of early animal evolution. Molecular clock studies—which estimate evolutionary timescales by analyzing genetic mutations—have long suggested that sponges, among the most primitive multicellular animals, originated deep in the Precambrian era, over 600 million years ago. Yet, the unequivocal fossil record of sponges with hard parts only begins around 535 million years ago, at the dawn of the Cambrian Explosion. The new 550-million-year-old fossil neatly bridges this 160-million-year chasm, confirming that sponges were indeed present and evolving long before they built durable skeletons that could easily fossilize. The implications for evolutionary biology are profound. By confirming the soft-bodied nature of early sponges, the finding shifts the paradigm for how and where scientists should hunt for the origins of animal life. Traditional fossil prospecting has often...

Lettura DEO

Decisione di validazione: publish

Risk score: 0.0

Il testo è stato ricostruito dai dati editoriali disponibili senza aggiungere fatti non presenti nel record sorgente.

Indicatore di affidabilità

Verificata — Alta confidenza. Fonti affidabili confermano la notizia.

Il sistema a semaforo

Ogni articolo su DEO include un indicatore di affidabilità:

• 🟢 Verificata — Alta confidenza. Fonti affidabili confermano la notizia.
• 🟡 In evoluzione — Confidenza moderata. Alcuni dettagli potrebbero ancora cambiare.
• 🔴 Contestata — Bassa confidenza. Fonti in conflitto o incertezze rilevanti.

Questo sistema esiste perché chi legge merita di sapere non solo cosa è successo, ma anche quanto la notizia è solida.

Categoria: cronaca