The most complete Pliocene mole fossil ever found in Europe reveals an unexpected evolutionary link to modern North American species
A team of researchers from the Institut Català de Paleoecologia Humana i Evolució Social (IPHES-CERCA), the Universitat Autònoma de Barcelona (UAB), and the Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA) has identified and described Vulcanoscaptor ninoti (“the Camp dels Ninots volcano digger”), a previously unknown genus and species of Pliocene mole. The fossil was unearthed at the Camp dels Ninots palaeontological site (Caldes de Malavella, Girona), one of the most important locations for studying the fauna that inhabited southern Europe more than 3.5 million years ago.
The specimen preserves the mandible with a complete dentition, part of the torso, and several bones from both the forelimbs and hindlimbs, many of them still in anatomical connection. This exceptional state of preservation is extremely rare in small mammals such as moles and makes this specimen one of the oldest and most complete ever found in Europe.
The study, published in the journal Scientific Reports (Nature group), was led by Adriana Linares, predoctoral researcher at the Universitat Rovira i Virgili and IPHES-CERCA, and Dr. Marc Furió, professor in the Department of Geology at the Universitat Autònoma de Barcelona and researcher at the Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA). This specimen represents the most complete mole fossil known to date from Pliocene Europe and provides valuable insights into the evolutionary history of talpids.
An unexpected evolutionary connection with North America
Anatomical and phylogenetic analyses revealed that Vulcanoscaptor ninoti belongs to the Scalopini, a tribe of moles that today are only found in North America and parts of Asia. This discovery in southern Europe’s Pliocene strata suggests a much more complex evolutionary and paleogeographic scenario than previously assumed.
“Despite its clearly fossorial morphology, this mole is closely related to extant North American species of the genera Scapanus and Scalopus, which points to a far more intricate evolutionary history for these animals than we had imagined ”, explains Dr. Marc Furió, co-author of the study. “Its presence in Europe suggests past transcontinental migrations of moles, challenging the assumption that they are mammals with low dispersal capacity.”
A remarkably complete specimen reconstructed in 3D
The fossil was partially embedded in a very compact sediment block and was extracted in its entirety during excavation. To examine it in detail without damaging it, the team used high-resolution micro-computed tomography (microCT) scanning, which enabled a precise three-dimensional digital reconstruction of the skeleton.
“With the microCT, we were able to analyze extremely small and delicate structures—such as phalanges and teeth—that would have been nearly impossible to study otherwise ”, explains Adriana Linares, lead author of the study and researcher at IPHES-CERCA. “This allowed us to identify unique anatomical features and incorporate them into a robust phylogenetic analysis, which confirmed the placement of the new taxon within the Scalopini.”
The preserved elements include the complete mandible with dentition, the right radius, ulna, and humerus, parts of the pectoral girdle, metacarpals, several phalanges, fused tibia and fibula, a posterior phalanx, and various bones of the foot. This extraordinary preservation offers a unique window into the functional anatomy and ecological adaptations of this mole.
Adapted for digging… and perhaps also for swimming?
The structure of the forearm and front limbs reveals a high degree of adaptation to a subterranean lifestyle. The humerus is particularly robust, with prominent crests and extensive areas for muscle attachment, while the phalanges suggest strong digging capabilities.
“However, the fact that this individual was preserved in lacustrine sediments and in a lateral position raises the possibility that it may also have had some aquatic locomotion abilities ”, adds Linares. “We can’t confirm this with certainty yet, but there are modern moles that are powerful diggers and also excellent swimmers.”
Camp dels Ninots, a unique site in Europe
The fossil was discovered in 2010 during systematic excavations at Ca n’Argilera, one of the sectors of the Camp dels Ninots site, where research has been ongoing since 2003.
Located in the municipality of Caldes de Malavella (La Selva), the Camp dels Ninots palaeontological site was declared a Cultural Asset of National Interest (BCIN) by the Government of Catalonia in 2015. It lies within the crater of a Pliocene maar volcano, later filled by lacustrine sediments deposited in anoxic conditions.
This environment has created exceptional preservation conditions, enabling the conservation of a rich, continuous, and remarkably well-preserved fossil record. As such, the Camp dels Ninots stands as a leading fossil-lagerstätte in Europe for this geological period.
The sedimentary sequence contains a wide range of vertebrate remains (including large mammals, microfauna, birds, amphibians, reptiles, and fish) as well as macrovegetal remains, pollen, and microorganisms. Particularly notable are the complete skeletons, often in anatomical connection, of large mammals such as Stephanorhinus jeanvireti, Alephis tigneresi, and Tapirus arvernensis, the latter represented by multiple individuals of varying ages, offering exceptional morphological and taphonomic data.
“Camp dels Ninots is an extraordinary site, in terms of both the quality and diversity of its fossil record,” says Dr. Gerard Campeny, co-director of the excavations and researcher at IPHES-CERCA. “It allows us to reconstruct entire ecosystems from this fascinating period: the Pliocene.”
Dr. Bruno Gómez de Soler, also co-director of the project, adds: “Discoveries like this would not be possible without the combination of an exceptional geological setting and rigorous, interdisciplinary research. The Camp dels Ninots fossil record is an inexhaustible source of scientific knowledge ”.
A key discovery for understanding mole evolution
The description of Vulcanoscaptor ninoti confirms that the evolutionary history of moles has been far more dynamic than previously thought, involving possible intercontinental dispersals and an underappreciated anatomical diversity. It also highlights the importance of exceptional fossil sites in documenting species rarely preserved in the fossil record, such as small mammals.
The study was made possible thanks to the collaboration of several institutions: IPHES-CERCA, Universitat Rovira i Virgili (URV), Universitat Autònoma de Barcelona (UAB), and the Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA).
Financing
The excavation project at Camp dels Ninots is funded by the Department of Culture of the Government of Catalonia through the four-year research project “The Plio-Pleistocene of Camp dels Ninots and the Prelitoral Depression: Palaeoclimatic Evolution, Faunal and Human Dispersals III”, and also receives logistical and financial support from the Caldes de Malavella City Council.
Link to artwork:
https://drive.google.com/drive/folders/1PwrOV1vBSsdUBZRgX_iEYRHcrieyLRmO?usp=sharing