This story has 128 years. It’s about a small mammal, a shrew, from Príncipe Island. Francisco Newton collected the specimen at the end of the 19th century. This month, Luís and Mariana helped to describe it as a new species in a scientific study published in “Mammalia” scientific journal.
Those who live on Principe Island call it Fingui, which means “small mouse”. This is a shrew that weighs about 12 grams, it has dark brown hair, thin tail and long tapered snout. People in the island say it is very common to find these fingui in old banana plantations and even inside their houses.
Until now it was believed that this species of shrew of the island of Príncipe was the same found in various regions of Central Africa, the Crocidura poensis. But several analysis and expeditions later, it was discovered that, after all, the small shrew from Príncipe was a completely different species, the Crocidura fingui. And it does not live anywhere else in the world.
Luis Ceríaco is a Post-Doc researcher at the California Academy of Sciences and associate curator of Herpetology collections at the National Museum of Natural History and Science, in Lisbon. He was intrigued when he studied the work of Francisco Newton, a Portuguese naturalist explorer who studied the island’s fauna at the end of the 19th century. “The story of the shrew fascinated me and I had to go to Príncipe Island”, he told Wilder.
In the deliveries of specimens sent by Newton to the Natural History Museum in Lisbon in 1887, he talked about “…six boxes containing birds, reptiles, insects and several other things. There goes an exemplar of an insectivore mouse that seems new to me…” But despite the Newton’s suggestion, it is only now that the shrew of Príncipe Island has earned its place in the world of Taxonomy.
In March 2013, Luís Ceríaco and Mariana Marques, a scientific collaborator at the Museum and researcher at the University of Évora, were in Príncipe Island for a week. They collected four specimens near villages, on a road surrounded by forests and near a river.
They concluded that the shrew from Príncipe Island is different from the one of the island of São Tomé and from all the other shrews of the species Crocidura , considered the most diverse kind of shrews, from Europe to Africa and Asia, with its greater diversity in Africa.
Fingui is smaller than the shrew of São Tomé (Crocidura thomensis) and, despite being morphologically similar to the shrew Crocidura poensis, is genetically different.
To be sure this is a separate species, the researchers went not only to Príncipe. “We were in San Francisco to study recently collected animals of the species C. thomensis and in the Natural History Museum in Paris where we measured several specimens of shrews and worked with French colleagues for the molecular studies and in the writing of the article”, he added.
The mystery of the shrew
But the mysteries around this small animal have not ended yet.
São Tomé and Príncipe are two islands in the Gulf of Guinea; they have one of the largest numbers of endemic species, that is, species only existing there and nowhere else, by area of the world. Many of them are waiting to be described, especially mammals. Currently there are only eleven species registered.
According to the scientific article, the only native mammals are bats and shrews. All the others were introduced. So, how have shrews arrived the island?
“We assume that the species has come on a natural raft, coming from a river of the Gulf of Guinea”, Luis Ceríaco said. “These rafts are pieces of logs and mud that sometimes are dragged by rivers. Taking into account that the system of currents takes many of these rivers to the area of Príncipe, it is probable that the colonization has occurred this way”. But there are no certainties yet.
One thing is sure, the island of Príncipe has its own species of shrew. “The discovery of new species for science is always important, it gives us the opportunity to raise the veil that still hides much of the natural world”, noted the researcher.
“At a time when we risk losing species that perhaps we never happened to know, each species we can describe is a small victory in this race against time”, he added.
And the Natural History collections help to do this work. “Without the collections it would be impossible to make the necessary comparison to confirm the differences (and similarities) between species, a fundamental process for the description of species”.