Episesarma+singaporense

**//Episesarma singaporense// (Tweedie, 1936)**

**Singapore vinegar crab** One of the most common crabs in the mangroves, //Episesarma singaporense// plays an important role in its habitat. It primarily feeds on leaves, and lives within burrows and on trees (Sivasothi, 2000). Like other tree-climbing crabs, //E. singaporense// possesses a carapace (shell) with reticulated (net-like) patterns on the area next to its mouthparts (Tan et al., 1988). However, the Singapore vinegar crab is characterised by its claws that are completely red.

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= **Taxonomy** =

**Synonym:**
**Other names people have used in the past** //Sesarma singaporensis// Tweedie, 1936(See taxonomic history for more information)

**Etymology:**
**How the crab got its name** This crab species was first discovered in Singapore; hence it was named in reference to the location of first collection (i.e. Singapore).

** Diagnosis: **
**How to tell //E. singaporense// apart from other crabs in the mangroves** In Singapore, there are currently __three__ described species of __tree-climbing crabs__— //E. singaporense//, //E. chengtongense// and //E. versicolor.// These three species can be __differentiated from other mangrove crabs__ by the following features: 1) The quadrangular (squarish) and dorsally flattened (flat on top) carapace (shell). 2) High carapace (shell) and sharply deflexed (angled downwards) front ("face"). 3) Reticulated (net-like) patterns with fine setae (hairs) on the pterygostomial regions (area around mouth-parts). 4) On the palm of the male chela (claw), there are small raised teeth (sharp bumps) that run from the proximal (towards the body) to the distal end (away from the body). <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">Among these three species, __//E. singaporense//__ can be __differentiated__ from the rest by the __colour of their chelae__ (claws)— //E. singaporense's// claws is completely __red__ (with the fingers a darker shade than the palm); while the other two species have white and purple colourations.

= ** Biology ** =

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">** Diet: **
<span style="color: #000000; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">//Episesarma singaporense//, like other species from the genus, feeds mainly on foliage (Sivasothi et al., 1993; Sivasothi, 2000). However, it has also been known to feed on other plant material (leaf-litter, flowers and propagules) and scavenge on meat (Sivasothi et al., 1993; Lim et al., 1999).

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Life Cycle:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">Largely nocturnal, //E. singaporense//, inhabits estuarine conditions their entire adult lives. Gravid females produce numerous small eggs (Soh, 1969), that develop into larvae much like other sesarmine crabs. These stages include four zoea and one megalopa stage; and morphological differences can be used in identification (see description below). These larval stages eventually develop into adults of carapace width 30-38 mm (see description below). Reproduction and spawning cycles of //E. sinagporense// have yet to be determined.

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Predator avoidance:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">The crabs normally climb trees to avoid aquatic predators like fishes. However, when threatened by other animals while on the tree, the crabs leap into the water, and climb another tree thereafter (Sivasothi, 2000). = ** Ecology ** =

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Habitat:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">//Episesarma singaporense// are mainly found in mangrove forests (Sivasothi, 2000). They tend to live within burrows excavated at the roots of mangrove trees and Mud-lobster (//Thalassina anomala//) mounds, only climbing up trees during high tide events. Additionally, they tend to be found in greater numbers at inland mound systems (Sivasothi, 2000).

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Distribution:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">Mangroves of South-east Asia— E.g. Brunei Darussalam, Indonesia, Malaysia, Singapore and Thailand.

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Conservation:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">While all //Episesarma// crabs are not evaluated by IUCN red-list assessment, //E. singaporense// currently appears to be abundant in the mangroves of Singapore.However, while they are unlikely to face threats from pollution and eutrophication (Lee, 1998), they are susceptible to habitat loss due to the fact that their range is restricted to the mangroves (Sivasothi, 2000). This, coupled with the fact that mangroves of South-east Asia are facing increasing destruction (Alongi, 2002), indicates that habitat loss could present a potential threat to these crabs in the future.

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Ecological Services:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">

<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">Like other crabs from the family Sesarmidae, //E. singaporense// plays a vital role in nutrient cycling. Their consumption of leaves and plant propagules (Sivasothi, 2000) helps breakdown vegetative materials, increasing the speed of recycling of mangrove leaf-litter (Lee, 1997, 1998). Moreover, their burrowing activities can alter the substrate topography and biochemistry as well (Kristensen, 2000).

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Human uses:**
<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 14px; text-align: left;"> <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">//Episesarma singaporense//, like other Sesarmine crabs, is known to be consumed as food in several cultures. The Teochews preserve the crabs in black vinegar, then cook and eat them with porridge (left). Additionally, the Thais and Cambodians also preserve the crabs in salt, eating it with variations of a papaya salad (Lim et al., 1999). .

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= ** Taxonomic Details ** =

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Taxonavigation:**
==<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> == **<span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Relative position of //E. singaporense// in higher order groupings ** <span style="color: #0000ff; display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">(This allows one to identify biological groupings of the crab. Note that taxon ranks were intentionally omitted due to subjectivity in namings.) <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">- Animalia Linnaeus, 1758<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">--- - Arthropoda Latreille, 1829<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">--- -Crustacea Brünnich, 1772<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> -Malacostraca Latreille, 1802<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">- -Decapoda Latreille, 1802<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> -Brachyura Linnaeus, 1758<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> -Grapsidae Macleay, 1838<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> -Sesarmidae Dana 1851<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> -//Episesarma// de Man 1895//<span style="color: #ffffff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> -Episesarma singaporense// (Tweedie, 1936)

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Phylogenetic Position:**
<span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Relative (phylogenetic) position of //E. singaporense// among other crabs.** <span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">(This figure only highlights the position of //E. singaporense// amongst other members of the subfamily Sesarmidae and family Grapsidae) <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;"> <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">This figure shows that //E. mederi//, //E. singaporense// and //E. palawanense// are monophyletic, thus providing support for their genus grouping.

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Taxonomic History:**
<span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">(This history allows for one to easily establish which particular species past researchers were referring to) <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Originally described by Tweedie (1936) as //Sesarma// //singaporensis//, this species was later reassigned to genus //Neoepisesarma// by Serene & Soh (1970), due to confusion regarding the original genus (Holthuis, 1978; Tan & Ng, 1994). However, //Neoepisesarma// was later determined to be synonymous with //Episesarma,// with the latter having nomen nudum (Holthuis, 1978; Tan & Ng, 1994). Hence, //Episesarma// is currently used as the genus name and the tense of the species name (//singaporensis//) was altered to //singaporense// to accommodate the genus //Episesarma//.
 * <span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">The history of how the name of the crab changed from //S. singaporensis// to //E. singaporense// **

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Type information:**
<span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Where the original specimens (that were first described) are stored in** <span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">(The type provides a reference point for when a species was first named. This is often important for determining the correct application of a species name in taxonomic research) <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">For //E. singaporense//, syntypes (two specimens that were listed in description of species) were used, and a holotype was not designated. <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">These syntypes (one male and one female) were collected by Tweedie in June 1935 (Tweedie, 1936). Specimens were deposited and are currently stored in the Raffles Museum of Biodiversity Research (Singapore).

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Description**
<span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Morphological features of //E. singaporense// that can be used for identification** <span style="color: #0000ff; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">(Both adult and larval forms have been described)

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Original description

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">**Adult:[[image:supercrab.jpg width="560" height="403" align="right"]]**
<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Carapace— High with sharply deflexed front (Soh,1969). Free edge of which is less sinuous than other allied species (Tweedie, 1936). Carapace is almost quadrangular and dorsally flattened (Serene & Soh, 1970), with width of 30-38 mm (Tweedie, 1940). Epibranchial teeth are present along the lateral margins, behind the external orbital teeth,the latter of which is typically acute (Soh, 1969). <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Pterygostomial regions— Pterygostomial regions around mouth has a reticulate pattern with numerous setae. <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Chela— Colouration of entire chela is entirely red (with both dactylus and pollex of a deeper shade) (Tweedie, 1936). Few coarse teeth are located on the pectinated ridge of the palm of males; females do not possess the pectinated ridge, but rather a raised line of granules (Tweedie, 1936). The tubercles on the upper margin of dactylus typically range from 36-46 in males and roughly 30 in females (Tweedie, 1936, 1940). The number of tubercles on dactylus normally increases with age and size of specimens (Tweedie, 1940). In males, tubercles are typically small, transverse and parallel-sided in the proximal end, but larger and more triangular-shaped at the distal end (Tweedie, 1936). The length of tubercles (measured along axis of dactylus) increases gradually from the proximal end to the distal end, with the latter being more than twice as long as the former (Tweedie, 1940). In females, tubercles only occupy the proximal two-thirds of the dactylus, and are typically smaller and less developed than males (Tweedie, 1936). <span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Ambulatory legs— Posterior border of meri pereopods (2nd-5th) lack denticulations. Merus width of third pereopod are generally equal to or greater than half its length (Soh, 1969). <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">Pleopod— First male pleopods is very slightly expanded at the tip, and quite distinct from other allied species (Tweedie, 1940)**.**

<span style="font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Larval stages:**
<span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">There are morphological differences between the different larval stages, namely the four zoeal and single megalopa stage. These differences are determined by the number of setae on the various body parts. Teo (unpublished) described these stages and determined that they can be used for differentiating between various species of sesarmine crabs. However, as the author is currently in the process of publishing his work, these stages would not be displayed on the website presently. .. =<span style="color: #fc3131; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">**Links to other websites:** = <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px; text-align: left;">World Register of Marine Species (WoRMS)SeaLifeBaseGuide to Mangroves of Singapore = = <span style="color: #fc3131; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 14px;">Comments <span style="color: #fc3131; display: block; font-family: 'Book Antiqua'; font-size: 17.3333px; text-align: left;">include component="comments" page="Episesarma singaporense" limit="10" = = = ** Literature cited: ** = <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Alongi, D. (2002) Present state and future of the world's mangrove forests. //Environmental Conservation//, **29**, 331-349 <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">De Man, J. (1895) Bericht über die von Herrn Schiffscapitän Storm zu Atjeh, an den westlichen Küsten von Malakka, Borneo und Celebes sowie in der Java-See gesammelten Decapoden und Stomatopoden. Zweiter Theil. //Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Thiere//, **9**, 75–218. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Fratini, S., Vannini, M. & Cannicci, S. (2005) Tree-climbing mangrove crabs: a case of convergent evolution. //Evolutionary Ecology,// **7**, 219–233. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Holthuis, L. (1978) A Collection of Decapod Crustacea From Sumba, Lesser Sunda Islands, Indonesia. //Zoologische Verhandelingen//, **162**, 3–56. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Kristensen, E. (2008) Mangrove Crabs as Ecosystem Engineers; with Emphasis on Sediment Processes. //Journal of Sea Research//, **59**, 30–43. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Lee, S. (1997) Potential Trophic Importance of the Faecal Material of the Mangrove Sesarmine Crab Sesarma Messa. //Marine Ecology-Progress Series//, **159**, 275–284. <span style="font-family: 'Times New Roman',Times,serif;">Lee, S. (1998) Ecological Role of Grapsid Crabs in Mangrove Ecosystems: a Review. //Marine and Freshwater Research//, **49**, 335–343. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Lim, K., Murphy, D., Sivasothi, N., Ng, P.K.L. & Tan, K. (1999) //A guide to the mangroves of Singapore II// (PKL Ng and N Sivasothi, Eds.). Singapore Science Centre, Singapore. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Schubart, C.D., Cannicci, S., Vannini, M. & Fratini, S. (2006) Molecular phylogeny of grapsoid crabs (Decapoda, Brachyura) and allies based on two mitochondrial genes and a proposal for refraining from current superfamily classification. //Journal of Zoological Systematics and Evolutionary Research//, **44**, 193–199. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Schubart, C.D., Liu, H.-C. & Ng, P.K.L. (2009) Revision of Selatium Serene & Soh, 1970 (Crustacea: Brachyura: Sesarmidae), with Description of a New Genus and Two New Species. //Zootaxa//, **2154**, 1–29. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Serene, R. & Soh, C.L. (1970) New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). //Treubia//, **27**, 387–416. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Sivasothi, N., Murphy, D.H. & Ng, P.K.L. (1993). Tree climbing and herbivory of crabs in the Singapore mangroves. In: A. Sasekumar (ed.), Mangrove fisheries and connections. Proceedings of the ASEAN-Australian Marine Science Project: Living Coastal Resources Workshop: 220-237. (ASEAN-Australia Marine Science Project, Malaysia). <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Sivasothi, N. (2000) Niche preferences of tree-climbing crabs in Singapore mangroves. //Crustaceana//, **73**, 25–38. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Soh, C.L. (1969) //Studies on some biological aspects of Sesarma (Decapoda, Brachyura) of Singapore//. Thesis (M.Sc.) - Dept. of Zoology, University of Singapore, 1970. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Teo, G. Y.J. (2011) //Complete morphology of the larvae of Singapore’s mangrove tree-climbing crabs (Decapoda: Brachyura: Sesarmidae)//. Thesis (Honors)- Dept. of Biological Science, National University of Singapore (2011). <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Tan, C.G.S. & Ng, P.K.L. (1994) An Annotated Checklist of Mangrove Brachyuran Crabs From Malaysia and Singapore. //Hydrobiologia//, **285**, 75–84. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Tweedie, M. (1936) On the Crabs of the Family Grapsidae in the Collection of the Raffles Museum. //The Bulletin of the Raffles Museum//, **12**, 44–70. <span style="display: block; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 12px; text-align: left;">Tweedie, M. (1940) New and interesting Malaysian species of Sesarma and Utica (Crustacea Brachyura). //Bulletin of the Raffles Museum//, **16**,88–114.