Centuries-old museum specimens unlock mysteries of South Asian treeshrews

Museum specimens, the Zoological Survey of India used to unlock morphological mysteries of the South Asian treeshrews.
| Picture Credit score: SPECIAL ARRANGEMENT

GUWAHATI

Scientists from the Zoological Survey of India (ZSI) have resolved longstanding taxonomic ambiguities surrounding South Asian treeshrews – small, insectivorous mammals usually misidentified because of their superficial resemblance to squirrels. Drawing upon century-old specimens housed in nationwide collections, the research affords recent perception into the morphological range of those elusive creatures.

Their research was revealed in Ecology and Evolution, a world journal, on Friday (April 25, 2025). The authors of the research are Manokaran Kamalakannan, Mukesh Thakur, Nithyanandam Marimuthu, Subhojit Pramanik, and Dhriti Banerjee.

Treeshrews are neither true shrews nor squirrels, however belong to a definite order referred to as Scandentia. Whereas they share an identical dimension and arboreal life-style with squirrels, treeshrews might be simply distinguished by their elongated snouts, diminished whiskers, moist nasal pads, and insectivorous or frugivorous weight loss program.

Traditionally misclassified as primates, the treeshrews – some arboreal, some semi-arboreal, and others terrestrial – at the moment are recognised as an historical lineage of mammals endemic to South and Southeast Asia.

Dr. Kamalakannan, the lead writer and scientist on the ZSI’s Mammal and Osteology Part, conceptualised and led the research from knowledge assortment to the ultimate morphological evaluation. “By analyzing decades-old museum specimens, we have now make clear how these fascinating mammals differ from each other,” he stated.

“This readability is important for correct species identification and for shaping efficient conservation insurance policies. When analysed with fashionable methods, museum specimens reveal patterns of variation that have been beforehand hidden, serving to us deal with long-standing taxonomic ambiguities,” he stated.

Co-author Dr. Marimuthu, who led the advanced multivariate analyses, stated: “The morphometric patterns we uncovered supply sturdy statistical help for separating these species, which have been as soon as thought to overlap considerably in dimension and form.”

Most strikingly, the research overturns long-standing assumptions in regards to the Nicobar treeshrew. As soon as believed to be the smallest amongst South Asian treeshrews, the evaluation reveals it’s the largest in South Asia and the third-largest of all 23 recognized treeshrew species globally.

Extra analysis suggested

“There’s a want for genetic research to help a complete phylogenetic evaluation of South Asian treeshrews. This needs to be a precedence for future analysis,” Dr. Thakur, one other co-author, stated.

Dr. Banerjee, additionally the Director of ZSI, underlined the implications of the findings. “This research is a significant step ahead in mammalian conservation in South Asia. Correct taxonomy is key to defending species, significantly insular endemics just like the Nicobar treeshrew, which faces rising ecological pressures,” she stated.

The analysis utilised a large dataset from South Asian treeshrew specimens preserved for over a century on the ZSI’s Nationwide Zoological Collections, a repository of India’s faunal range, in Kolkata.

The scientists investigated the morphological variation amongst three species – Madras treeshrew (Anathana ellioti), northern treeshrew (Tupaia belangeri), and Nicobar treeshrew (Tupaia nicobarica) – utilizing museum specimens collected over a large spatial and temporal vary of India and Myanmar and mixed with present revealed datasets.

These three species occupy distinct and non-overlapping geographical areas in India and Southeast Asia.

The scientists analysed 22 cranial measurements and 4 exterior traits to guage inter- and intraspecific morphological differentiation, using distance-based morphometric approaches validated by multivariate analyses. Their findings revealed appreciable heterogeneity in cranial morphology, with three species exhibiting clear differentiation, regardless of slight overlaps in morphospace.