Fossil remains of the light-edged bat (Pipistrellus kuhlii) have appeared in the Cueva de los Verdes in Lanzarote, but it no longer lives on this island, but it does on others in the Canary Islands. Paleontologists are wondering what happened in the ecosystem to cause its disappearance.
The enigma arises from the first study carried out on the fossil record of bats in the Canary Islands, which has been led by Javier González-Dionis, from the Paleontology area of the University of La Laguna (ULL) and a doctoral fellow at the Institute of Research in Paleobiology and Geology (CONICET) of the National University of Río Negro in Argentina.
The study also involved researchers Carolina Castillo, from the ULL; Penélope Cruzado and Elena Cadavid, from the National Council for Scientific and Technical Research of Argentina; and Vicente Crespo, from the Paleontological Museum of Valencia.
Javier González-Dionis explains in an interview with EFE that the study was carried out using fossil remains of bats found in Quaternary volcanic tubes, specifically in the aforementioned Cueva de los Verdes and in the Cueva Roja in El Hierro.
The fossil record of these mammals is usually scarce and consists mainly of isolated teeth and some articulated skeletons, explains the researcher, who points out that in the case of the Canary Islands, the volcanic nature favors the formation of lava tubes in which the fragile bat bones are well preserved.
Thus, remains have been found in paleontological and archaeological sites in Lanzarote, La Palma, Tenerife and El Hierro.
The sites where the oldest remains are found date back 700,000 years in La Palma (Cueva Honda del Bejenado) and the most recent, 800 years old, in Tenerife (Cueva de la Enladrillada). In Lanzarote and El Hierro they date from 20,000 and 4,000 years ago, respectively.
What has been unusual is to see that there are fossils of Pipistrellus kuhlii or the light-edged bat in Lanzarote, where this species no longer lives, while it has continued to inhabit Fuerteventura, Gran Canaria and Tenerife.
Regarding the current absence of the light-edged bat in Lanzarote, it indicates a loss of diversity in the mammal fauna in general and of bats in particular, and leads researchers to wonder if what happened on that island affected only this group of animals or could also affect others.
Paleontologists also believe it is necessary to compare the dentition of these specimens found in the Cueva de los Verdes with those from North Africa to help determine whether the animals found in the Canary Islands are of African or Iberian origin, explains Javier González-Dionis.
The fossil record indicates that there are two endemic bat species in the archipelago, Plecotus teneriffae and Pipistrellus maderensis, the first from the Canary Islands and the second also present in the Azores and Madeira, and no differences have been observed in their dental morphology with the current populations of these mammals.
More than fifteen species of bats inhabit the Macaronesia area and the islands with the highest number are the Canary Islands, with seven species and one subspecies, and Cape Verde, with six.
Of all of them, three are endemic, that is, exclusive to Macaronesia, and these are the Canarian long-eared or Plecotus teneriffae from the western islands of the Canary Islands, the Madeira bat or Pipistrellus maderensis, distributed between the archipelagos of the Azores, Madeira and the Canary Islands, and the Azores noctule or Nyctalus azoreum, exclusive to said archipelago.
There are also two endemic subspecies: the forest bat Barbastella barbastellus guanchae, from Tenerife and La Gomera, and the Nyctalus leisleri verrucosus from Madeira.
Paleobiological data shed light on the distribution, extirpation or extinction of bat species in the islands of the Mid-Atlantic and globally, says González-Dionis, a large part of the bat species, around 80 percent, are in danger of extinction.
In paleontology, research on fossil mammals, including bats, focuses on the study of dentition, which provides information on adaptations to the type of diet since the teeth have characteristics that make it possible to differentiate one species from another.
"In the studies on the fossil record of the bats of the Canary Islands carried out by paleontologists, the first problem that had to be solved was to determine what the teeth of the species of the islands were like, and for this the molars of the seven species of the archipelago were characterized", specifies González-Dionis.
