A recent study led by zoologist Francesco Nardelli and paleontologist Kurt Heibig proposes a new classification for the rarest rhinoceros in the world, the Javan rhinoceros, based on significant differences in its appearance and behavior compared to its closest relative, the Indian rhinoceros. The research, published in the ZooKeys journal, suggests that the independent evolution of both species justifies a new scientific name for the Javan species: Eurhinoceros sondaicus.
The Javan and Indian rhinoceroses evolved in different environments, which resulted in notable anatomical and ecological differences. The Javan rhinoceros, currently confined to the Ujung Kulon Peninsula in Indonesia, has a thinner skull, a short nose, and teeth adapted for browsing leaves. Its skin features a distinctive polygonal pattern, and the females, unlike any other current rhinoceros, lack horns.
On the other hand, the Indian rhinoceros, which inhabits the riverine grasslands of northern India and Nepal, has a more robust skull and teeth specialized for grazing on grass. Additionally, its physique is considerably larger, with males that can exceed 2,000 kilograms in weight. This difference in body structure is also reflected in their behavior: while the Javan rhinoceros is solitary, the Indian rhinoceros tends to establish temporary isolation zones.
Adaptations Depend on Food Sources
Researchers explain that the adaptations of large land mammals are closely related to the diversity of available food in their habitat. In the case of rhinoceroses, this relationship is manifested in the variation of their dental and cranial morphologies. Fossil evidence confirms that these differences have evolved independently for millions of years, supporting the reclassification proposal.
According to experts, recognizing the Javan rhinoceros as a distinct genus not only provides a better understanding of its evolutionary history, but also offers a clearer framework for its conservation. “A refined classification allows for designing more suitable protection strategies for these animals, whose situation in nature is critical,” conclude the study’s authors.
Javan rhinoceros. Photo: Gizmodo.
What Sets Javan Rhinoceros Apart from Indian Rhinoceros?
In general, the Javan rhinoceros is smaller than the Indian rhinoceros, weighing between 800 kilograms and 2.5 metric tons, while the smallest Indian rhinoceros weighs no less than 1,600 kilograms.
Another difference between these species is their horns. While both have a single horn, what sets them apart is that in the case of Javan rhinoceroses, only males develop horns. Additionally, the latter also differ in their swimming abilities, as they are not as proficient as Indian rhinoceroses.
However, there is a point that unites them, as the Javan rhinoceros, one of the rarest rhinoceros species, is critically endangered, while the Indian rhinoceros is classified as Vulnerable on the IUCN Red List.
Source: INVDES-Europapress.es
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