Nesorhinus philippinensis was first described by
Gustav Heinrich Ralph von Koenigswald in 1956 as
Rhinoceros philippinensis based on
fossil teeth that were excavated in
Cagayan province of Luzon island in the
Philippines in 1936. These bones were lost and he did not provide for a
holotype. A fossilized jaw of
N. philippinensis was unearthed by Mr. de Asis on May 13, 1965 in the
Fort Bonifacio area. The specimen was unearthed from an ash deposit produced by the volcano called the Guadalupe Formation. The specimen had a length of , width of , and a thickness of . It has a weight of . A 75% complete fossil of the
N. philippinensis was unearthed in
Rizal,
Kalinga along with 57 stone tools in 2014. A 2018 study placed the date of the rhino fossil at around 709,000 years old (dating to the early
Middle Pleistocene) after the rhino's tooth enamel was subjected to
electron spin resonance dating. The authors of the study found butchery marks on the bones of the ribs, metacarpals, and both humeri, suggesting that the rhino had been butchered by early humans or
hominins. While no bones from any hominin were reported from the site, over 50 stone tools found in context with the rhinoceros provided direct evidence for human activities at the site. It was declared the type species of the new genus
Nesorhinus in 2021. In 1971, when the fossil collector Chang-Wu Pan visited Zuojhen, he received several fossilized rhinoceros teeth from a local elementary school student, Shih-Ching Chen, who had found them in the riverbed of Cailiao River. Pan and Chen investigated where the rhinoceros teeth were found and speculated that the fossils had been washed out of the
mudrock layer along the riverbed, and that rhinoceros fossils might remain in the rock layer. This discovery was conveyed to Prof. Chao-Chi Lin of
National Taiwan University. In December 1971, a team was formed by
Taiwan Provincial Museum, including Prof. Chao-Chi Lin, Chang-Wu Pan, and Chun-Mu Chen (a well-known fossil collector from Zuojhen) to conduct the first excavation in Zuojhen to excavate rhinoceros fossils, including teeth and limb bones, but some limb bones were still preserved in the original stratum. In 1972, the team was joined by Japanese paleontologists Tokio Shikama and Hiroyuki Otsuka for the second excavation, and the remaining limb bones were excavated. The species was named as
R. sinensis hayasakai by Otsuka & Lin in 1984, named in honour of Ichiro Hayasaka. It is known remains found in Taiwan dating to the Early and Middle Pleistocene. == Description ==