Banyuwangi, E. Java. Scientists from the National Research and Innovation Agency (BRIN) have identified a previously unknown fish species in the shallow coastal waters of Banyuwangi, East Java, underscoring the country's vast and still largely unexplored marine biodiversity.

The discovery is more than just the addition of a new species to the scientific record. At a time when coastal ecosystems face mounting pressure from climate change, pollution, and overexploitation of marine resources, it serves as a reminder that much of Indonesia's biodiversity remains undocumented.

The newly identified species, Tomiyamichthys oriens sp. nov., belongs to the shrimpgoby group. The findings were published in the international scientific journal ZooKeys, Volume 1283 (2026), in a paper titled "Tomiyamichthys oriens, a new species of shrimpgoby (Teleostei, Gobiidae) from the coast of Banyuwangi, East Java, Indonesia."

The research was led by BRIN scientist Kunto Wibowo, together with Hilda M. Pratiwi, Anik B. Dharmayanthi, Agus Priyadi, Ruby V. Kusumah, Djohan Tjiptadi, and Wiwi Tarmini.

The discovery further reinforces Banyuwangi's reputation as one of Indonesia's richest marine biodiversity hotspots. Located at the eastern tip of Java, where the Bali Strait meets the waters of the Indian Ocean and the Bali Sea, the region supports interconnected coral reefs, seagrass meadows, and mangrove forests that provide critical habitat for thousands of marine species.

Surveys conducted by BRIN and the Marine Affairs and Fisheries Ministry in recent years have documented hundreds of species of reef fish, mollusks, crustaceans, and endemic marine organisms along the Banyuwangi coast, with many more still awaiting scientific study.

Indonesia lies at the heart of the Coral Triangle, a region that contains about 76% of the world's coral species and more than 2,000 species of reef fish, making it the global epicenter of marine biodiversity. Banyuwangi is a key part of this ecological network.

Confirmed Through DNA Analysis
Researchers identified the new species using an integrative taxonomic approach that combined detailed morphological examination with genetic analysis of the mitochondrial cytochrome c oxidase subunit I (COI) gene.

The study began with two specimens collected from Banyuwangi's shallow coastal waters. According to lead researcher Kunto Wibowo, combining physical characteristics with DNA evidence provides greater accuracy than conventional identification methods.

"We combined morphological characteristics with DNA analysis to obtain more comprehensive evidence. The results consistently showed that T. oriens possesses characteristics distinct from its closest relatives," Kunto said.

Morphologically, the fish closely resembles Tomiyamichthys hyacinthinus, a species found in Japan. However, researchers identified clear differences in fin-ray counts, scale counts, gill-raker numbers, and body coloration.

Genetic analysis further supported the discovery, revealing a DNA divergence of approximately 3.1% from its closest known relative—a level considered sufficient in fish taxonomy to classify it as a distinct species.

Inspired by the "Sunrise of Java"
The fish, which measures only a few centimeters in length, features five bright orange blotches along its body, small yellow markings on its head, and, in males, two elongated filaments extending from the first dorsal fin.

Its distinctive coloration inspired the species name oriens, derived from the Latin word for "east" or "sunrise." The name also pays tribute to Banyuwangi, widely known as the "Sunrise of Java."

"We hope this discovery will encourage further research into Indonesia's extraordinary marine biodiversity," Kunto said.

Despite its formal identification, many aspects of Tomiyamichthys oriens remain unknown.

Many shrimpgoby species live in a symbiotic relationship with burrowing shrimp: the fish acts as a lookout for predators while the shrimp provides a shared burrow for shelter. Whether T. oriens exhibits the same ecological partnership has yet to be confirmed and remains a subject for future research.

For BRIN, the discovery represents more than the addition of another species to the world's biological record. It demonstrates that Indonesia's coastal waters continue to harbor numerous organisms that have yet to be scientifically documented.