The waters of North Sulawesi, part of the Indo-Pacific region, have once again captured the world's attention with the discovery of two rare sea slug species.
The ZooKeys journal introduces Phyllidia ovata and Phyllidia fontjei. These shell-less sea slugs (nudibranchs) belong to the Phyllidiidae family and are known for their stunning colors.
This discovery not only adds to Indonesia's long list of marine biodiversity but also highlights the crucial role of global collaboration in uncovering nature's hidden treasures.
Three-Nation Collaboration
The discovery of these two new species is the result of an international collaboration involving researchers from Germany, Indonesia, and Wales.
Exploration in North Sulawesi's waters has long been a focus for scientists, as the area is home to hundreds of nudibranch species. Although more than 350 species have been recorded, it is estimated that about 100 more have yet to be officially identified.
What makes this discovery special is the participation of divers and underwater photographers. Their photo contributions provided the crucial initial data for researchers to conduct further identification.
Phyllidia ovata: The Elegant White Slug Often Misidentified
For over two decades, Phyllidia ovata was often misidentified as other species like Phyllidia picta due to its similar appearance. The name "ovata" itself refers to its oval body shape. However, after in-depth analysis, scientists concluded it was a new species.
Key features of P. ovata include:
- Color: A clean white body with black patches in the middle.
- Shape: Features bright tubercles (small bumps) with yellow tips.
- Size: Can grow up to 50 mm (2 inches).
- Distribution: Found in the waters of Indonesia, the Philippines, Japan, Taiwan, and Australia, but most sightings are recorded in Indonesia and the Philippines.
Phyllidia fontjei: Honoring an Indonesian Scientist
The second species, Phyllidia fontjei, is named in honor of Dr. Fontje Kaligis, an Indonesian scientist who has made significant contributions to global nudibranch research. This is a proud tribute to the Indonesian marine research community.
Unlike its relative, P. fontjei has distinct characteristics:
- Size: Much smaller, only about 16 mm (0.6 inches).
- Color: Dominated by a white body with bright orange patches in the center and striking black stripes.
- Shape: It lacks large tubercles, instead featuring three smooth ridges and small grains scattered across its body surface.
- Discovery: The first specimen was found near Bunaken Island at a depth of 25.3 meters, resting on a sea sponge.
Unique and Rare Habitats in Southeast Asia
This research also introduced new terminology in taxonomy, the "glandular oral tube," an important organ in the feeding process that helps classify Phyllidia species more accurately in the future. Furthermore, P. fontjei is known to reach sexual maturity at a much smaller size compared to other related species.
Despite being found in a biodiversity hotspot, both species are very difficult to find. P. ovata is widely distributed but remains rare.
Meanwhile, P. fontjei has a more limited distribution in the Southeast Asian region, found only in Indonesia, Malaysia, and parts of the Andaman Sea. Researchers suspect their populations are very small or that they have highly specific habitats, causing their striking colors to be camouflaged by the rich colors of the coral reefs.
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These aren’t just rare sea slug. They’re metaphors for what’s still unknown in Indonesia’s underwater realms. They remind us that even in a well-explored region like Southeast Asia, the ocean continues to whisper secrets some beautiful, some urgent. If we listen carefully and act decisively we might preserve both.
