learn only 3 things about them ...
Decapods have ten limbs. Some are walking legs, others
They are found in a wide range of habitats. Many can tolerate
being out of water.
live with other animals; anemone shrimps, porcelain crabs.
Decapods! Decapods include our favourite seafood! Having
to personally dismantle some of these creatures to eat them, many
of us are more familiar with them than we might imagine. Decapods
include crabs, prawns and shrimps, lobsters and hermit crabs.
What are decapods? Decapods represent
almost one-quarter of all known crustaceans.
from Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
Order Decapoda has three general groups
'Deca' means ten and 'poda' means foot. Indeed, members of this Order
have 10 leg-like appendages. 5 pairs are usually walking legs while
1-3 may be tipped with claws.
The abdomen may also have appendages called pleopods that are used
in swimming. Or to generate water currents, particularly important
for females that brood eggs or young. The tail is made up of a pair
of abdominal appendages called the uropods.
The head and thorax are rigidly fused and not separated by a flexible
joint. Sometimes, the head and thorax may be covered by a carapace
or shell so that these function as a single unit called the cephalothorax.
The shell may be hardened with calcium compounds. Most have compound
eyes and two pairs of head appendages (insects only have one pair
of antennae). The head also has smaller appendages, including the
mandibles that crush food and maxillae that generate water currents
and help manipulate food. Most have appendages that are branched (biramous).
These may function as gills or gill-cleaners.
True crabs or Brachyurans: There
are about 4,500 known species in nearly 50 families. True crabs generally
have have a reduced abdomen that fits under the cephalothorax resulting
in the typical crab-shape that we are all familiar with.
Not all crab-like animals are true crabs. For example, porcelain crabs
uses: Decapods are eaten by people everywhere. But not
all crabs are edible. Some crabs in fact, are highly poisonous and
their toxins are not destroyed even by cooking. Eating such crabs
can kill humans. Crabs may also concentrate unpleasant substances
from the food that they eat. You may get ill eating these crabs. Don't
eat any crabs that you caught yourself in the wild.
Status and threats: Sadly, many
of our beautiful and fascinating decapods are listed among the endangered
animals of Singapore. Like other marine creatures, they are vulnerable
to habitat loss due to reclamation or human activities along the coast
that pollute the water. They are also vulnerable to trampling by careless
visitors and over-collection for food can affect local populations.
The Flower crab and
are among our favourite seafood!
Changi, Jun 05
Unlike true crabs, hermit
a soft abdomen which is protected by
tucking it into an empty snail shell
St. John's Island, May 04
- Ng, Peter
K. L. and Daniele Guinot and Peter J. F. Davie, 2008. Systema
Brachyurorum: Part 1. An annotated checklist of extant Brachyuran
crabs of the world. The Raffles Bulletin of Zoology. Supplement
No. 17, 31 Jan 2008. 286 pp. (Online
PDF on the Raffles Bulletin of Zoology website)
- Tan, Leo
W. H. & Ng, Peter K. L., 1988. A
Guide to Seashore Life. The Singapore Science Centre,
Singapore. 160 pp.
- Ng, Peter
K. L. & N. Sivasothi, 1999. A
Guide to the Mangroves of Singapore II (Animal Diversity).
Singapore Science Centre. 168 pp.
crabs on the Life
on Australian Seashores by Keith Davey on the Marine Education
Society of Australia website: Fact sheets with photos, labelled
diagrams, and even animated gifs with details on various species
found in Australia.
- From the
wild shores of singapore blog:
- Chou, L.
M., 1998. A
Guide to the Coral Reef Life of Singapore. Singapore Science
Centre. 128 pages.
- Lim, S.,
P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life
and Times of Labrador Beach. Division of Biology, School of
Science, Nanyang Technological University & Department of Zoology,
the National University of Singapore. 160 pp.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
P., 1990. A
Colour Guide to Dangerous Animals.
Venom & Toxin Research Group, Faculty of Medicine, National
University of Singapore. 156 pp.
- Jones Diana
S. and Gary J. Morgan, 2002. A Field Guide to Crustaceans of
Australian Waters. Reed New Holland. 224 pp.
Helmut, 2001. Crustacea
Guide of the World: Atlantic Ocean, Indian Ocean, Pacific Ocean
IKAN-Unterwasserachiv, Frankfurt. 321 pp.
Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral
Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii
exclusive of the vertebrates
Sea Challengers. 314pp.
- Morton, Brian
& John Morton, 1983. The
Sea Shore Ecology of Hong Kong.
Hong Kong University Press. 350 pp.
- Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004. Invertebrate
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963.
Jan A., 2005. Biology
of the Invertebrates.
5th edition. McGraw-Hill Book Co., Singapore. 578 pp.