After nearly two centuries of studying the nudibranch genus Thecacera, marine biologists have discovered a remarkable new species off Taiwan’s coast. Measuring less than 3 millimeters, this tiny, translucent sea slug with distinctive black and yellow spots has expanded our understanding of marine biodiversity in the western Pacific.
- New nudibranch species found off Taiwan is tiny and translucent
- Thecacera sesama measures less than 3 mm, resembling a sesame seed
- Discovery underscores hidden diversity in Western Pacific waters
What happened
For nearly 200 years, scientists recognized six species within the nudibranch genus Thecacera, all known to inhabit seas worldwide and measuring around half an inch to an inch in length. This changed when a Taiwanese undergraduate diver, Ho-Yeung Chan, spotted an exceptionally small sea slug near Keelung port, which sparked interest among marine researchers.
After seven years of study involving DNA extraction from the tiny size-limited bodies and careful morphological examination, the translucent slug decorated with small black and yellow spots was confirmed as a new species. Named Thecacera sesama due to its sesame seed-like size and shape, it exhibits about a 14.17% genetic difference from its closest known relative, Thecacera picta.
Why it feels good
Discovering Thecacera sesama brings a joyful reminder that even long-studied scientific fields like marine biology still hold delightful surprises. It celebrates the curiosity and dedication of young scientists and highlights the wonder of tiny creatures thriving unnoticed in complex ecosystems.
This find also enriches our appreciation of the biodiversity surrounding Taiwan and emphasizes how much remains to be uncovered in the ocean’s mysterious depths, inspiring conservation efforts and scientific exploration in marine habitats.
What to enjoy or watch next
For those fascinated by marine life, keep an eye out for more discoveries of similarly tiny and elusive creatures in the waters around Taiwan and the wider Western Pacific region. Researchers suspect that Thecacera sesama is just one of many species yet to be identified in these rich ecosystems.
Also worth watching are the interactions of such sea slugs with their habitat, including their relationship with bryozoans—moss-like marine organisms on which T. sesama feeds and lays eggs. Some of these bryozoans themselves may be new to science, opening more doors to exciting future research.