Tiny New Mammal Species Discovered in Ethiopia: Meet Crocidura stanleyi

A team of international scientists has officially identified a new mammal species in the southern Ethiopian highlands, describing it in a study published in the Journal of Vertebrate Biology. Weighing just 3 grams and measuring 5 centimeters in length, this tiny shrew, now named Crocidura stanleyi, was recognized as distinct after genetic and morphological comparisons with a specimen caught in 2015. The discovery underscores the rich biodiversity of the region and the enduring possibility of finding new species even in the 21st century. A Decade-Long Puzzle Solved In The Highlands Of Ethiopia The discovery of Crocidura stanleyi is the result of nearly a decade of fieldwork, patience, and scientific collaboration. In 2023, during a research expedition in southern Ethiopia, a team of researchers was repeatedly catching what they believed were familiar highland rodents. After ten days of routine trapping, a remarkably small shrew was discovered at the bottom of a pitfall trap, a moment that would change the trajectory of the study, published in the Journal of Vertebrate Biology. “I will never forget that moment. I called out to the others. The little shrew looked like something we had only seen once before,” recalls Yonas Meheretu, one of the co-authors of the study and a researcher at the Swedish University of Agricultural Sciences. His memory refers to a similar shrew found in 2015 by late evolutionary biologist Bill Stanley, whose original specimen would eventually serve as the holotype, the single physical example used to formally describe the new species. Upon close genetic analysis and anatomical review, scientists determined that the specimens from 2015 and 2023 belonged to the same species, Crocidura stanleyi, previously undocumented by science. A Tribute To A Lost Scientist And The Spirit Of Discovery The naming of the new species carries deep emotional resonance within the scientific community. The shrew’s species name, stanleyi, honors William “Bill” Stanley, who passed away shortly after discovering the first known specimen in 2015 during his work in a different part of the Ethiopian highlands. His contribution, initially unconfirmed, proved pivotal nearly a decade later. “It was an obvious choice to name it after Bill Stanley, who meant so much to us and to the field of research. We were deeply moved when it became clear that he had been lucky enough to find a new species,” says Dr. Evan Craig, the study’s lead author and evolutionary ecologist at the University of Massachusetts Boston. This posthumous recognition bridges time and memory, highlighting how field science often builds on forgotten moments, samples, and field notes. It also shows how naming can carry personal as well as scientific meaning. Published Findings Highlight Rich Biodiversity In The Ethiopian Highlands The study, featured in the Journal of Vertebrate Biology, places Crocidura stanleyi within the complex ecosystem of the Ethiopian highlands, a region well known for its endemism. Ethiopia is home to more than 100 rodent species, with 43 endemic to these elevated terrains—an indicator of the region’s unique environmental conditions and evolutionary isolation. While Crocidura stanleyi is remarkably small, it is not the smallest shrew in the world. That title still belongs to the Etruscan shrew (Suncus etruscus), which weighs just 1.8 grams and measures around 4 centimeters. Nevertheless, the discovery of stanleyi emphasizes that even small and elusive creatures can have a major scientific impact. As Dr. Craig remarked in the study, “I thought, wow, what an exciting time to be a biologist. We are still living in an era where we get to enjoy the discovery of species, the most fundamental unit of biodiversity.” Rediscovery Reflects Hope For Future Breakthroughs This discovery is not just a testament to Ethiopia’s rich and still partially undocumented fauna, it’s a reminder that the natural world holds secrets in even its most minuscule forms. In an era of biodiversity loss and accelerating extinctions, every new species described is a cause for renewed attention and scientific curiosity. The case of Crocidura stanleyi also highlights the importance of museum collections, long-term field data, and interdisciplinary research. The fact that a small mammal could be first spotted and then forgotten for nearly a decade before its identity was confirmed demonstrates the hidden value in specimens stored away or initially overlooked.