From coal to fossils
From a distance, anyone stumbling upon the scene might have called the police, convinced they were witnessing some sort of shady deal. Two young men in boots and raincoats stood beside a small hatchback with its trunk open, parked at the end of a dead-end street facing a fenced-off lot — one more destined to host a house identical to the many that have mushroomed across Portugal’s suburbs. And yet, despite there being no doubt that Pedro Correia, driven by the kind of fervor that could make him sell anything to anyone, was capable of persuasion in its purest form, nothing was being traded that day except knowledge.
“Palaeontology saved me. School was hard — I struggled, I spoke very late — but I already had this dream of becoming a palaeontologist, of being a scientist. I held on to it,” confesses Pedro Correia, the palaeobotanist at the University of Porto responsible for the most significant discoveries of Carboniferous plant fossils in Portugal over the past fifty years.
Here, on a modest plot in São Pedro da Cova, a parish in the municipality of Gondomar, Portugal, Pedro Correia and his team carried out an excavation barely larger than a parking space. It was there they unearthed Portugal’s first fossilised spider, three new species of plants, and two insects — one of which defined an entirely new taxonomic genus, a group of organisms sharing common traits.
A hundred metres up the hill, the rumble of cement mixers, the clatter of hammers and the hiss of angle grinders betray a more troubling reality: before long, this 300-million-year-old flora and fauna may find themselves buried beneath foundations and concrete — their fragile story lost under the weight of yet another house.
“Palaeontology saved me. School was hard but I already had this dream of becoming a palaeontologist, of being a scientist. I held on to it”
Pedro Correia
São Pedro da Cova: a past built on coal, a future written in fossils
São Pedro da Cova was once one of Portugal’s most important coal-producing centres. The mines, where anthracite was extracted, closed on 25 March 1970. They remain an extraordinary testament to the nation’s mining heritage and to a time when this industry was a powerful engine of the economy. In the early decades of the 20th century, at the height of mining activity, the pits produced nearly 300,000 tonnes of coal a year (1939) and employed hundreds of workers from across the country. Life was hard, unhealthy, and marked by constant poverty.
Thanks to post-industrial investment and EU structural funds, São Pedro da Cova today bears little resemblance to the place it was when the mines were operating. There are swimming pools, a new miners’ neighbourhood, and sports halls. Yet the material and cultural legacy of the mines has largely been neglected. The Mining Museum, housed in the former Casa da Malta — once a dormitory for labourers brought in from other regions, known locally as “malteses” — is run by the parish council, which has for years appealed to Gondomar’s municipal authority for support in preserving the architectural heritage left behind after the mines closed.
Seen from this vantage point, São Pedro da Cova carries the unmistakable weight of an old mining town whose glory has long since drained away. The hillside is crowded with small, working class, close-packed houses, a patchwork of colours that can’t quite brighten the greyness of everything. For the young, the future here is stunted, those who can leave, almost always drift towards Porto.
“We’ve repeatedly asked the municipality to allocate funds in its budget for preserving this heritage — particularly the headframe, which is classified as a structure of public interest. In 2018, only a thousand euros were earmarked for that purpose. And, moreover, the mining complex was inexplicably left out of the Serras do Porto project — a joint initiative by the municipalities of Gondomar, Valongo and Paredes, created in 2018 to promote and protect the natural heritage of these territories — even though its boundaries literally meet the old colliery’s spoil heap,” explains Micaela Santos, who manages the São Pedro da Cova Mining Museum.
Judging by the way Gondomar’s municipality has responded to palaeontologist Pedro Correia — who contacted the council in an effort to secure protection for the São Pedro da Cova fossil site but received no reply — the indifference appears to run deep. Valongo is no exception. In 2011, the opening of a road in Montes da Costa, Ermesinde, exposed a Carboniferous rock sequence that Correia has been studying ever since, and where a new plant species was identified. He met with the mayor of Valongo in early 2018; since then, not a single response.
“These sites, together with the mining heritage of São Pedro da Cova, share the same Carboniferous geological formations. It was from these units that coal was extracted — and it is within these same layers that we find these fossils. Protecting them together has enormous geotouristic potential, and it would make perfect sense to include them in the Serras do Porto project,” says Pedro Correia.
The headframe of the coal mine, the structure that once held the pulleys hauling the lift up and down the mineshaft. From here, the wagons loaded with coal were carried by aerial cable all the way to Porto.
The study of the past as a window onto the future
Pedro Correia’s romance with palaeontology is an old one, born of those fortunate accidents that spark lifelong passions. The collection he built over the years between São Pedro da Cova and Valongo was his foundation. After completing his degree at the Faculty of Sciences at the University of Porto (FCUP), Pedro returned to his home region for his internship. From there, he went on to his PhD — a journey that took him to the Czech Republic, funded by the Calouste Gulbenkian Foundation, and later to Canada, where he worked with his co-supervisor, Professor James Brendan Murphy of St. Francis Xavier University in Nova Scotia.
“Since childhood I’ve always been drawn to palaeontology. I was lucky enough to grow up in a place rich in trilobite fossils — Valongo, where I’m from, holds one of the world’s most important trilobite records — and I had a neighbour studying Biology and Geology who lent me her books. All of that awakened this passion and made me dream of studying Geology purely because of Palaeontology.”.
Pedro Correia
One of the new species Pedro identified at the Montes da Costa site was named in Murphy’s honour: Acitheca murphyi, an arborescent fern whose closest relatives (A. polymorpha) are more commonly found in North America’s fossil record. The discovery, published in 2017 in the Geological Journal, strengthens evidence of the ancient connection between Portugal and West Virginia during the age of the supercontinent Pangaea.
The plant’s unusual features — including elongated sporangia roughly a centimetre long — show that it could store significant amounts of water, suggesting that this region once endured dry spells and high temperatures. Geological indicators at the site also point to a catastrophic flooding event: in other words, a sudden shift in climatic conditions. For Pedro Correia, all of this leads to a compelling conclusion: “This site preserves something remarkable — a transition from the warm, humid tropical climate typical of the time to a much drier one.”
The Montes da Costa fossil site in Ermesinde, where the new species Acitheca murphyi was discovered.
Practically all of Pedro’s work focuses on the Carboniferous strata of the Douro Basin. These layers were deposited between 359 and 299 million years ago in a continental sedimentary basin - a large, low-lying area of the Earth's crust where sediments accumulate over geological time, often forming a thick sequence of sedimentary rock - stretching some 53 kilometres / a long, narrow strip that rarely exceeds 500 metres in width. Over the years, Pedro and his team have identified nearly fifty floral species within this basin, some described for the first time in the Portuguese Carboniferous record. In total, they have identified five new plant species and three new species of insect.
One of these new plants was found on the very plot now up for sale in São Pedro da Cova. The team of palaeontologists, palaeobotanists and palaeoentomologists named it Annularia noronhai, in honour of the eminent FCUP professor Fernando Noronha. In doing so, Pedro is not only recognising a key figure at the University of Porto, but also expressing his personal gratitude.
“Professor Noronha was one of those people who always valued and encouraged me. In his own peculiar way he’d always ask, ‘So, have you been to pick your cabbages yet?’ — his nickname for ‘my’ fossil plants.”
Pedro Correia
The presence of extensive coal seams, the long-established palaeobotanical record described by earlier authors, and the fossil assemblage found alongside Annularia noronhai all point to the same conclusion: this sedimentary basin once lay firmly inland. As the authors note, “the discovery site preserves several fossil-bearing layers containing abundant remains of plants and animals. Annularia noronhai was found alongside a diverse flora comprising multiple fossil taxa belonging to ferns and seed ferns. The faunal assemblage also includes traces of millipedes, arachnids, eurypterids, insects, and non-marine bivalves.”
These remains — recovered through excavations not unlike those carried out in archaeology — were studied by comparing them with species already described in the scientific literature and by using scanning optical microscopy, a form of electron microscopy capable of generating high-resolution, near-three-dimensional images of a specimen’s surface. This technique makes it possible to analyse the fine structure of each fossil in remarkable detail. The findings suggest that these plants thrived in transitional environments along the margins of freshwater rivers or lakes, in a landscape framed by mountain ranges.
As Pedro Correia explains, “300 million years ago, the Iberian Peninsula lay very close to the equator, which made it a tropical to subtropical region. What is now the Douro corresponded to an isolated zone sourrounded by mountains. The climate would have been seasonal, with an extremely dense forest and a great diversity of plants.”
It was likely this geographical isolation that drove a distinct faunal evolution, producing various endemisms — groups of animals or plants found only in a particular area. One can imagine the region as a landscape of swampy lakes nestled at the foot of mountain ranges, surrounded by luxuriant vegetation composed of countless plant species of all sizes.
“If we could travel back in time, we’d find plants reaching thirty metres — the famous calamites — or tree-sized ferns. We’d probably be terrified to see giant arthropods like enormous centipedes and scorpions”
Pedro Correia
Much of this flora, preserved in the sediments that once settled at the bottom of these basins, now emerges as fossils embedded in slate-like rocks. They form exceptional palaeobiogeographical markers: clues that allow us to reconstruct the climate and environment that existed at the moment these plants and animals were entombed in stone. Palaeobotany’s power lies in its ability to resurrect lost worlds — to read ancient climates and landscapes in the shape of a leaf or the architecture of a sporangium — and it is precisely this capacity that makes it so urgent today. As Pedro puts it, the field offers a way to understand how past life responded to climatic upheaval, and thus a key to anticipating how present-day biodiversity might weather the storms ahead.
Correia’s recent discoveries — emerging from a network of collaborations stretching from Prague to Wales, Grenoble to Lisbon — speak both to the scientific richness of the region and to the possibilities that open up when international expertise converges. Already, the team has papers accepted on ancient parasitoid insects, on the reconstruction of Pangaea’s palaeoclimate, and on new fossil plants. More projects have been submitted to the Portuguese Science and Technology Foundation and the National Geographic Society; more fieldwork will follow. But the path is slow, and rarely secure. One discovery may take nearly a decade to bring to print. And behind the polished pages of Historical Biology or Geological Journal lies a reality common to many Portuguese researchers: precarious funding, long stretches without support, and the stubborn hope that the work itself — the fossils, the stories they tell, the worlds they reveal — will be enough to keep them going. “I’ll admit it’s not easy to see our projects approved by funding agencies. The only encouragement comes from the discoveries themselves, because right now I earn nothing — I’m unemployed,” he confides.
The researcher acknowledges that scientists spend most of their time investigating, interpreting, and documenting evidence — which is precisely why, he argues, “the media play a fundamental role in communicating and disseminating scientific work, especially in bringing new knowledge to a general audience (and not only to those already within the sciences).” Asked about the visibility of the geosciences in the press, the University of Porto palaeobotanist is blunt:
“This field doesn’t receive the attention it deserves, except in areas like palaeontology where — especially with dinosaurs — public interest tends to be high. It’s important to show people just how present the geosciences are in their everyday lives.”
And so Pedro Correia sees his work as part of that wider mission: to change the narrative, to make the invisible visible, and to keep fighting for the preservation of the Carboniferous sites he holds so dearly.
Artistic reconstruction of Acitheca murphyi, showing different parts of the plant in life: on the left, its arborescent fern-like form; centre, a terminal pinna; top right, a cross-section of a fertile pinnule with markedly elongated sporangia; bottom right, a complete fertile pinnule in lateral view. Illustration by the paleoartist Sergey Krasovskiy.
