Discover the ‘Queen Crab’: A Royal Legacy of Biodiversity at Chulalongkorn University 

Her Majesty Queen Sirikit, the Queen Mother, has long emphasized the importance of science—particularly environmental and agricultural science. She has continuously supported efforts in plant and animal conservation as well as environmental preservation. Her Majesty initiated numerous natural resource conservation projects, reflecting her ecological scientific vision. Her royal initiatives and activities have inspired educational and research institutions across Thailand to place increasing importance on conservation-oriented research, especially in biology, environmental science, and biotechnology, in order to carry forward her guiding principles for a balanced development of the economy, society, and the environment. 

Scientific institutions, botanical gardens, and natural history museums have bestowed her royal name upon newly discovered species of plants and animals to honor her contributions to the conservation of Thailand’s biodiversity. 

One of the most iconic research achievements by the Faculty of Science at Chulalongkorn University in honor of Her Majesty Queen Sirikit, the Queen Mother, is the discovery of the “Queen Crab”, a freshwater crab of striking coloration. It was named the “Queen Crab” to commemorate Her Majesty on the occasion of her 60th birthday. Chulalongkorn University received royal permission to use Her Majesty’s name for this newly discovered freshwater crab species on December 23, 1991. 

The “Queen Crab” has the scientific name of Thaiphusa sirikit (Naiyanetr, 1992). Its local names include pu sam si (three-colored crab), pu trairong (tricolor crab), and pu pa (forest crab). Its English common names are Regal Crab and Terrestrial Crab. It was discovered in 1983 by Mr. Suraphon Duangkae, then a master’s student at Mahidol University, together with Prof. Emeritus Paiboon Naiyanetr of the Department of Biology, Faculty of Science, Chulalongkorn University. The crab was first found in a forest stream near Ban Nam Chon, Sai Yok District, Kanchanaburi Province. It has also been reported in Huai Khayeng Subdistrict, Thong Pha Phum District, Kanchanaburi. 

The Queen Crab is characterized by three colors—red, white, and dark bluish purple. All four pairs of walking legs are red. The sides of the carapace and both claws are white. The center of the carapace and the eye sockets are dark bluish purple. The lip area is red. The carapace is smooth and convex, wider than it is long, measuring 17–48 mm in width. When fully grown, the crab’s carapace is about 5 centimeters wide. 

The Queen Crab typically inhabits stream banks and hillsides, digging burrows 0.5 to 1 meter deep. During the rainy season, it emerges to mate and molt, revealing its vivid and majestic colors—worthy of the name “Queen Crab,” a freshwater species of global value. It is classified as a protected wildlife species under the Wild Animal Reservation and Protection Act of 1992. 

The discovery of the “Queen Crab” not only brought pride to Thailand’s scientific community but also served to highlight the richness of the nation’s natural resources, many of which remain waiting to be discovered. 

You can meet the “Queen Crab” and view the exhibition in honor of Her Majesty Queen Sirikit, the Queen Mother, during the “Night at the Museum” event from December 12–14, 2025, 4:00 p.m.–10:00 p.m., at the Faculty of Science, Chulalongkorn University. 

Acknowledgment: 

– Exhibition honoring Her Majesty Queen Sirikit, the Queen Mother, at the 51st International Conference on Science, Technology, and Technological Innovation (STT51) 

– “Crayfish, Shrimps, and Crabs of Thailand Given Royal Scientific Names” by Prof. Emeritus Paiboon Naiyanetr, Department of Biology, Faculty of Science, Chulalongkorn University 

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