Cerberus+rynchops

** Dog-faced water snake ** ** //Cerberus rynchops// (Schneider, 1799) ** = = toc

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=Name = Sc ientific Name: //Cerberus rynchops// (Schneider, 1799) Common Name: Dog-faced water snake; Asian Bockadam snake It was first described as //Hydrus rynchops// by Schneider in 1799 in [|Historiae amphiborum naturalis et literariae]. It was later revised as //Cerberus rynchops// by Gyi, 1970.

Etymology
<span style="font-family: Georgia,serif; font-size: 110%;">The word, //Cerberus//, means a "three-headed doglike monster with serpent's tail that guarded the gated of hades, hell-hound". <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;">The species epithet, //rynchops//, is probably derived from a combination of the Greek words, rhyncho = "nose, snout, or muzzle", and ops = eye. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;">(Reference from: Brown, R. W., 1956. Composition of scientific words. //Smithsonian Books, Washington//. Pp 275, 659.)

=<span style="color: #000000; font-family: Georgia,serif; font-size: 20px;">Taxonavigation = <span style="font-family: Georgia,serif; font-size: 120%;">Order: Squamata <span style="font-family: Georgia,serif; font-size: 120%;">Family: Homalopsidae <span style="font-family: Georgia,serif; font-size: 120%;">Genus: //Cerberus// Cuvier, 1829 <span style="font-family: Georgia,serif; font-size: 120%;">Species: //Cerberus rynchops// (Schneider, 1799)

<span style="font-family: Georgia,serif; font-size: 120%;">Family Homalopsidae (Oriental-Australian rear-fanged water snakes) consists of 10 genera with a total of 34 species of snakes. (Gyi, 1970; Voris //et al//., 2002; Alfraro //et al//., 2004; Murphy, 2007; Alfraro //et al.//, 2008)

<span style="color: #404040; font-family: Georgia,serif; font-size: 19px;">Genus //Cerberus Cuvier, 1829//
<span style="font-family: Georgia,serif; font-size: 120%;">There are 3 species within this genus (Gyi, 1970).
 * 1) <span style="font-family: Georgia,serif; font-size: 120%;">//Cerberus australis// (Gray, 1842)
 * 2) <span style="font-family: Georgia,serif; font-size: 120%;">Cerberus microlepis //Boulenger, 1896//
 * 3) <span style="font-family: Georgia,serif; font-size: 120%;">//Cerberus rynchops// (Schneider, 1799)

<span style="font-family: Georgia,serif; font-size: 120%;">These 3 species can be differentiated based on their morphological traits, the biogeographical regions as well as the genetic divergence showed in the study by Alfaro //et al.//, 2004.

=<span style="font-family: Georgia,serif; font-size: 110%;">Diagnosis = <span style="font-family: Georgia,serif; font-size: 120%;">For //Cerberus rynchops//, its head shields are not defined clearly and the parietals scales are fragmented into small scales. It is not easy to distinguished //C. rynchops// from //C. australis// morphologically//.// The head scales that are anterior to the jaws for //C. australis// are not keel unlike in //C. rynchops//. //C. rynchops// can be distinguished from //C. microlepsis// by the difference in the number of dorsal scales along the middle of the body where //C. rynchops// has between 21-25 while //C. microlepsis// has between 27-29.

=<span style="color: #000000; font-family: Georgia,serif; font-size: 110%;">Description = <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">__Original description of //Cerberus rynchops// (Schneider, 1799)__: <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">Schneider, J. G., 1799. Historiae amphibiorum naturalis et literariae. //Impressus Ienae, Jena: Sumtibus Friederici Frommanni//. Pp 246-247. (View [|PDF] ) <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">Elongated head that is distinct from the neck. Small eyes that are situated on the top of the head, near the snout as seen in the photo on the right. The frontal scales (in purple) are small in size and the parietals scales (in yellow) are fragmented into smaller scales. There is a dark stripe through the snout to neck across each eye. <span style="font-family: Georgia,serif; font-size: 110%;">There are between 22-27 dorsal scale rows on the neck, 21-25 dorsal scales rows on the middle of the body (where normally its either 23 or 25), and 16-20 dorsal scales rows on the back of the body (where its normally 17). Scales are strongly keeled. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">The snakes exhibit variation in colouration and pattern. Dorsum (Top surface of the body) of the snake is usually uniformly grayish (A) or brownish (B) in colour with dark cross bands that will extend to its tail. The underside of the snake is yellowish in colour.

<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">Adults can grow up to 1m in total length.

=<span style="color: #000000; font-family: Georgia,serif; font-size: 110%;">Biology = <span style="font-family: Georgia,serif; font-size: 110%;">

<span style="color: #404040; font-family: Georgia,serif; font-size: 110%;">Diet
<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">//C. rynchops// are generalist piscivores (Jayne //et al.//, 1988; Voris and Murphy, 2002). They are noted to be an opportunistic predators for fish prey (Murphy, 2007). <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">After striking at its fish prey, it will move the fish backwards to the side of its mouth and the fish would be hold perpendicular to its neck (Jayne //et al.//, 1988). This action can be seen in the photo (left) and the video (below) which shows the movement of the snake after striking the fish prey. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="font-family: Georgia,serif; font-size: 110%;">They are observe to hunt more actively in the evening and night time.

media type="file" key="Cerberus rynchops feeding.mov" width="330" height="330" align="center"

<span style="display: block; font-family: Georgia,serif; font-size: 110%; text-align: center;">Video showing the behaviour after striking a prey (Taken by Mary-ruth Low, 2011)

<span style="color: #404040; display: block; font-family: Georgia,serif; font-size: 120%; text-align: justify;">Venom
<span style="display: block; font-family: Georgia,serif; font-size: 120%; text-align: justify;">The venom of this snake is considered to be mildly venomous (Baker and Lim, 2008; Ng //et al.//, 2008). Based on the experiment done by Alcock and Rogers (1902), the venom fluid from an adult snake is able to kill small mammals in full dosage. A new group of snake venom proteins was also identified from this species and more research on the function of the snake venom is still ongoing (OmPraba //et al//., 2010).

<span style="color: #404040; display: block; font-family: Georgia,serif; font-size: 120%; text-align: left;">Reproduction
<span style="display: block; font-family: Georgia,serif; font-size: 120%; text-align: justify;"><span style="font-family: Georgia,serif;">This species give birth to live young. There are a number of literature on the snake reproduction throughout the years in various location. It shows that the litter size of the species ranges from 5 to 38 (Murphy, 2007). The seasonality for the reproduction appears to differ with locality. As suggested by Jayne //<span style="font-family: Georgia,serif;">et al. //(1988)<span style="font-family: Georgia,serif;">, the reproduction for the snake population in Malaysia is aseasonal. For the snake population in Singapore, the reproduction is aseasonal as well (Chim, pers. comm.).

<span style="color: #404040; font-family: Georgia,serif; font-size: 120%;">Behaviour
<span style="font-family: Georgia,serif; font-size: 120%;">media type="custom" key="11203932" align="right" width="90" height="90"The snake was noted to be docile and would not exhibit any aggressive character when approached (wall, 1918). Based on personal observation, the snake also exhibit a docile nature and would not show aggression when approach in field. <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: justify;"><span style="display: block; font-family: Georgia,serif; font-size: 120%; text-align: left;">An interesting motion was noted from this snake and that is, this species of snake was observe to be able to jump. However, this jumping action is not its usual mode of locomotion and such instances are very rare. Such a jumping action could be because the snake was threatened and could be used as a mode for escape (Chim, pers. comm.) <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"><span style="display: block; font-family: Georgia,serif; font-size: 120%; text-align: left;">This jumping action was capture in a documentary by BBC, "Life in Cold blood", featuring Sir David Attenborough. This jumping action, however, was only observe and documented once. <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"><span style="display: block; font-family: Georgia,serif; font-size: 120%; text-align: left;">There has been no known research done thus far. Therefore, there is no conclusive evidence as to why the snake is able to jump. <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"><span style="display: block; font-family: Georgia,serif; font-size: 120%; text-align: left;">Video on the right shows the jumping action of the Dog-faced water snake (From 2:24 to 2:47). The part of the documentary featuring the jumping snake and the crab-eating water snake was shot in Singapore's mangroves. <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: left;">

=<span style="color: #000000; font-family: Georgia,serif; font-size: 110%;">Ecology =

<span style="color: #404040; font-family: Georgia,serif; font-size: 110%;">Natural enemy
<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;">Predators of //C. rynchops// was observed to be crustaceans as the snake scales was found within the gut contents of the mangrove mud crab, //Scylla serrata// (Voris and Murphy, 2002). <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;">Humans are known to kill the snake and is considered to be its major predator (Murphy, 2007). The dog-faced water snake are sometimes entangles in fishing nets and would drown or the fishermen would kill the snake (Murphy, 2007). The snake's skin are also collected for used in the leather trade for ornamental purposes (Murphy, 2007).

<span style="color: #404040; font-family: Georgia,serif; font-size: 110%;">Habitat type
<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;"> It is a coastal marine species that is commonly found in brackish waters in the mangroves, estuaries, coastal zones and mudflats (Gyi, 1970; Tweedie, 1983; Jayne // et al. //, 1988; Karns // et al // ., 2000). This species has been showed to have salt gland which allows it to be able to tolerate and adapt to the salt water environment (Dunson & Dunson, 1979). <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;">Even though the snake are frequently found in brackish water as well as salt water, they are also found in freshwater occasionally. Based on field observation in Tioman, this species of snake was seen in freshwater streams both during the day and night. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;">

<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;"> In Singapore, they are commonly sighted in the mangroves and mudflats. Based on field observation, during the day, they can be found hiding in burrows or underneath debris such as cloth or canvas sheet. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: justify;"><span style="font-family: Georgia,serif; font-size: 110%;">Based on a study of the dog-faced water snake in Singapore by Karns //et al.// (2002), it was shown that the snake is normally associated with open muddy pools area within the mangrove. During low tide, they are also observed to move about in tidal pool or along the small stream within the mangrove.

=<span style="color: #000000; font-family: Georgia,serif; font-size: 110%;">Distribution = <span style="font-family: Georgia,serif; font-size: 120%;"> It is widely distributed in Southeast Asia (Tweedie, 1988; Jayne //et al//., 1988; Alfraro //et al//., 2004; Alfraro //et al//., 2008). It was recorded from the far west of India, to far east of Sunda Islands; they are also found in the Palau Islands (Gyi, 1970).

media type="googlemap" key="http://maps.google.com/maps/ms?vpsrc=0&ctz=-480&ie=UTF8&msa=0&msid=210438334352773414575.0004b17127278463df89a&t=m&ll=5.790897,103.886719&spn=66.00701,105.292969&z=3&output=embed" height="400" width="600" align="center" Map showing the distribution range of Dog-faced water snake. (Reference from Murphy, 2007) The pointer shows the type locality of the species.

<span style="color: #404040; font-family: Georgia,serif; font-size: 110%;">Distribution within Singapore
<span style="font-family: Georgia,serif; font-size: 120%;">It is native to Singapore and is commonly found within the mangroves and mudflats in Singapore (Grandison, 1978; Tweedie, 1983; Lim and Lim, 2002; Ng and Sivasothi, 2002; Lim and Baker, 2008; Ng //et al.,// 2008; Das, 2010).

=<span style="font-family: Georgia,serif; font-size: 110%;">Status of //Cerberus rynchops// = <span style="font-family: Georgia,serif; font-size: 120%;">According to IUCN red list, the conservation status of this species is of least concern. However, there are still potential threat to this species as it was collected for its skin in the past for the leather trade in some countries. It is not known whether such practices are still continued today due to a lack in data.

<span style="color: #404040; font-family: Georgia,serif; font-size: 120%;">Conservation actions
<span style="color: #404040; font-family: Georgia,serif; font-size: 120%;">This species is listed in [|Appendix III] of CITES. It is also protected under [|The Indian Wildlife (Protection) Act, 1972].

=<span style="font-family: Georgia,serif; font-size: 20px; line-height: 30px;">Type information = <span style="font-family: Georgia,serif; font-size: 120%;">According to Gyi (1970), this species was described by Schneider (1799) from the illustration by Russell (1796), plate 17.

<span style="font-family: Georgia,serif; font-size: 120%;">//Cerberus rynchops// is the type species of the genus //Cerberus// Cuvier, 1829 (Gyi, 1970). <span style="font-family: Georgia,serif; font-size: 120%;">[The species that was used to describe the genus; a representative of the genus]

<span style="font-family: Georgia,serif; font-size: 120%;">Type locality: **Ganjam, India**. <span style="font-family: Georgia,serif; font-size: 120%;">[The location where the specimen of this species was first described from.]

=<span style="font-family: Georgia,serif; font-size: 110%;">Link to other pages on //Cerberus rynchops// = <span style="font-family: Georgia,serif; font-size: 120%;">Wild fact sheet by Ria Tan on // [|Cerberus rynchops] // <span style="font-family: Georgia,serif; font-size: 120%;">Ecology Asia: [|Dog-faced Water Snake] by Nick Baker

=<span style="font-family: Georgia,serif; font-size: 110%;">Literature and references = <span style="font-family: Georgia,serif; font-size: 120%;">Alcock, A. & L. Rogers, 1902. On the toxic properties of the saliva of certain "non-poisonous' Colubrines. //Proceedings of the Royal Society of London//, **70**: 446-454. (View [|PDF])

<span style="font-family: Georgia,serif; font-size: 120%;">Alfaro, M. E., D. R. Karns, H. K. Voris, E. Abernathy & S. L. Sellins, 2004. Phylogeny of //Cerberus// (Serpentes: Homalopsinae) and phylogeography of //Cerberus rynchops//: diversification of a coastal marine snake in Southeast Asia. //Journal of Biogeography//, **31**: 1277-1292.

<span style="font-family: Georgia,serif; font-size: 120%;">Alfraro, M. E., D. R. Karns, H. K. Voris, C. D. Brock & B. L. Stuart, 2008. Phylogeny, evolutionary history, and biogeography of Oriental-Australian rear-fanged water snakes (Colubroidea: Homalopsidae) inferred from mitochondrial and nuclear DNA sequences. //Molecular Phylogenetics and Evolution//, **46**: 576-593.

<span style="font-family: Georgia,serif; font-size: 120%;">Baker, N. & K. K. P. Lim, 2008. //Wild animals of Singapore: A photographic guide to Mammals, Reptiles, Amphibians and freshwater fishes//. Draco Publishing and Distribution Pte. Ltd., Singapore. p. 109.

<span style="font-family: Georgia,serif; font-size: 120%;">Chim C. K., November 2011. Enquire about //Cerberus rynchops//. [Personal communication]

<span style="font-family: Georgia,serif; font-size: 120%;">Dunson, W. A. & M. K. Dunson, 1979. A possible new salt gland in a Marine Homalopsid snake (//Cerberus rynchops//). //Coperis//, **4**: 661-672.

<span style="font-family: Georgia,serif; font-size: 120%;">Das, I., 2010. //A field guide to the reptiles of South-East Asia//. New Holland Publishers Ltd., United Kingdom. p. 325

<span style="font-family: Georgia,serif; font-size: 120%;">Grandison, A. G. C., 1978. Snakes of West Malaysia and Singapore. //Ann. Naturhistor. Mus. Wien//, **81**: 283-303. (View [|PDF])

<span style="font-family: Georgia,serif; font-size: 120%;">Gyi, K. K., 1970. A revision of Colubrid snakes of the subfamily Homalopsinae. //University of Kansas Publications, Museum of Natural History//, **20**(2): 47-223. (View [|PDF] for //Cerberus rynchops//)

<span style="font-family: Georgia,serif; font-size: 120%;">IUCN Red List-//Cerberus rynchops.// URL: [] Accessed on 1 November 2011.

<span style="font-family: Georgia,serif; font-size: 120%;">Jayne, B. C., H. K. Voris & K. B. Heang, 1988. Diet, feeding behavior, growth, and numbers of a population of //Cerberus rynchops// (Serpentes: Homalopsinae) in Malaysia. //Fieldiana Zoology, New Series//, **50** (View [|PDF])

<span style="font-family: Georgia,serif; font-size: 120%;">Karns, D. R., A. O'Bannon, H. K. Voris & A. W., Lee, 2000. Biogeographical implications of mitochndrial DNA variation in the Bockadam snake (//Cerberus rynchops//, Serpentes: Homalopsinae) in Southeast Asia. //Journal of Biogeography//, **27**: 391-402.

<span style="font-family: Georgia,serif; font-size: 120%;">Karns, D. R., H. K. Voris & T. G. Goodwin, 2002. Ecology of Oriental-Australian rear-fanged water snakes (Colubridae: Homalopsinae) in the Pasir Ris Park Mangrove forest, Singapore. //The Raffles Bulletin of Zoology//, **50**(2): 487-498. (View [|PDF])

<span style="font-family: Georgia,serif; font-size: 120%;">Lim, K. K. P. & F. L. K. Lim, 2002. //A guide to the amphibians and reptiles of Singapore//. Revised edition, Singapore Science Centre, Singapore. p. 76.

<span style="font-family: Georgia,serif; font-size: 120%;">Murphy, J.C. An annotated bibliography to the Oriental-Australasian rear-fanged water snakes (Serpentes: Homalopsidae). <span style="font-family: Georgia,serif; font-size: 120%;">URL: [|http://www.jcmnaturalhistory.com/COMLIT.pdf.] Accessed on 8 November 2011.

<span style="font-family: Georgia,serif; font-size: 120%;">Murphy, J. C., 2007. Homalopsid snakes: Evolution in the mud. Krieger Publishing Company, Malabar, Florida. Pp 39-50, 63-72.

<span style="font-family: Georgia,serif; font-size: 120%;">Murphy, J. C., 2011. The nomenclature and systematics of some Australiasian Homalopsid snakes (Squamata: Serpentes: Homalopsidae). //The Raffles Bulletin of Zoology//, **59**(2): 229-236. (View [|PDF])

<span style="font-family: Georgia,serif; font-size: 120%;">Ng, P. K. L. & N. Sivasothi, 2002. //Guide to the mangroves of Singapore II: Animal diversity//. Second edition, Singapore Science Centre, Singapore. p. 144.

<span style="font-family: Georgia,serif; font-size: 120%;">Ng, P. K. L., Wang L. K. & K. K. P. Lim, 2008. //Private lives: An exposé of Singapore's Mangroves//. The Raffles Museum of Biodiversity Research, Singapore. p.164.

<span style="font-family: Georgia,serif; font-size: 120%;">OmPraba, G., A. Chapeaurouge, R. Doley, K. R. Devi, P. Padmanaban, C. Venkatraman, D. Velmurugan, Q. Lin & R. M. Kini, 2010. Identification of a novel family of snake venom proteins Veficolins from //Cerberus rynchops// using a venom gland transcriptomics and proteomics approach. //Journal of Proteome Research//, **9**: 1882-1893.

<span style="font-family: Georgia,serif; font-size: 120%;">Schneider, J. G., 1799. Historiae amphibiorum naturalis et literariae. //Impressus Ienae, Jena: Sumtibus Friederici Frommanni//. Pp 246-247.

<span style="font-family: Georgia,serif; font-size: 120%;">Tweedie, M. W. F., 1983. //The snakes of Malaya//. Third edition, Singapore National Printers Pte. Ltd//.,// Singapore.Pp 23,103, 104, 157.

<span style="font-family: Georgia,serif; font-size: 120%;">Voris, H. K. & J. C. Murphy, 2002. The prey and predators of Homalopsine snakes. //Journal of Natural History//, **36**: 1621-1632. (View [|PDF])

<span style="font-family: Georgia,serif; font-size: 120%;">Voris, H. K., M. E. Alfraro, D. R. Karns, G. L. Starnes, E. Thompson & J. C. Murphy, 2002. Phylogenetic relationships of the Oriental-Autralian Rear-Fanged Water Snakes (Colubridae: Homalopsinae) based on mitochondrial DNQ sequences. //Copeia//, **4**: 906-915.

<span style="font-family: Georgia,serif; font-size: 120%;">Wall, F., 1918. A popular treatise of the common Indian snakes. //Journal of the Bombay Natural HIstory Society//, **26**: 89-97. (View [|PDF])

=<span style="font-family: Georgia,serif; font-size: 120%;">Comments = <span style="font-family: Georgia,serif; font-size: 120%;">If you have any additional information or queries regarding this species of snakes, feel free to drop your comments below. <span style="font-family: Georgia,serif; font-size: 120%;">media type="custom" key="11332576"