Meet Ho-Yeung Chan, the student who accidentally discovered a new sea slug smaller than a grain of rice

An accidental encounter by a student during a recreational dive has led to the formal description of a ‘tiny new sea slug’ from the waters of north-eastern Taiwan. ‘Ho-Yeung Chan’ first noticed the animal while diving and later helped establish that it belonged to a species previously unknown to science. Named ‘Thecacera sesama,’ this sea slug is less than 3mm long, making it smaller than a grain of rice. Its translucent white body is covered with tiny black spots, larger yellow markings and distinctive white patches. The discovery was confirmed through detailed research that examined both the slug’s physical features and its genetic material. Published in ‘ZooKeys,’ the study shows how even a tiny creature can reveal overlooked marine diversity.