Tue 28 Apr 2015: 2pm @ SR2 – Lee Bee Yan on the spider crabs of Singapore

Qualifying Exam

“The spider crabs of Singapore, and a revision of Hyastenus White, 1847, and Rochinia A. Milne-Edwards, 1875 (Majoidea: Epialtidae: Pisinae)”

Ms Lee Bee Yan
Graduate Student,
Department of Biological Sciences,
National University of Singapore

Tue 28 Apr 2015: 2.00pm
Seminar Room 2 (S2,04-15)
Department of Biological Sciences

Supervisor: Prof Peter Ng K L
Co-Supervisor:  Dr Ng Ngan Kee
All are welcome


Majoid crabs are a group of widely distributed crustaceans, with a total of six families. This project is in three main parts. Firstly, there has not been a formal checklist of the Majoidea of Singapore except an unpublished list by Ow-Yang (1963), who listed 25 valid species of spider crabs from three majoid families. The status and taxonomy of these brachyuran crabs need to be revisited after more than five decades, especially with the substantial changes in the brachyuran systematics which have taken place in the interim. This project is also feasible in view of the recent Comprehensive Marine Biodiversity Survey (CMBS) which has obtained a large series of spider crabs from Singapore – thus now, a revised comprehensive checklist of the Majoidea can be conducted.

Secondly, although the superfamily Majoidea Samouelle, 1819, is one of the largest superfamilies in the Brachyura with 892 species, there have been few recent revisions of its members. The family Epialtidae MacLeay, 1838, is the largest of the six families within Majoidea. The two selected genera, Hyastenus White, 1847, and Rochinia A. Milne-Edwards, 1875, for revision are the most species-rich genera. Although diverse in species and common in many habitats, their taxonomy is still poorly resolved. Hence, the aim for this part of the project is to revise and refine the systematics of the two selected genera.

Lastly, these crabs, commonly known as decorator crabs, are known to pick debris from their surroundings to attach to their carapaces and legs, serving as a form of camouflage. Though there are reviews of the decoration behaviour of these crabs, little is known about the species found within the Indo-West Pacific region. This project will review the decorating behaviour and functional morphology of the setae and spine of Majoidea, in particular, in taxa from the Indo-West Pacific region.

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