Hydrosaurus pustulatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Agamidae

Scientific Name: Hydrosaurus pustulatus
Species Authority: (Eschscholtz, 1829)
Common Name(s):
English Crested Lizard, Sail-fin Lizard, Sailfin Water Lizard, Soa-soa Water Lizard
Taxonomic Notes: Two species of Hydrosaurus are currently reported from the Philippines; H. amboinensis in the south and H. pustulatus in the north. However, there is some confusion in the identification of species and consequently the distribution of these species. Further taxonomic studies are needed to clarify the distribution of Hydrosaurus in the Philippines (A. Diesmos pers. comm., 2007).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2acd+4acde ver 3.1
Year Published: 2009
Date Assessed: 2007-04-22
Assessor(s): Ledesma, M., Brown, R., Sy, E. & Rico, E.L.
Reviewer(s): Cox, N. & Hoffmann, M. (Global Reptile Assessment Coordinating Team)
Listed as Vulnerable because it is suspected that a population decline, estimated to be more than 30% would be met over a ten-year period which is ongoing from the recent past to the near future, inferred from habitat loss and the very heavy collection of this species for the pet and food trade.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to the Philippines, however its distribution is unclear because of confusion in identification between Hydrosaurus amboinensis and H. pustulatus. Populations of H. pustulatus have been reported from the islands of Luzon (with recent records from Bicol), Polillo, Mindoro, Negros, Cebu, Guimaras, Panay, Masbate, Tablas, Romblon, Sibuyan, and Catanduanes. It may be present on the island of Bohol but this requires confirmation.
Countries occurrence:
Additional data:
Upper elevation limit (metres):800
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Animals can be very common in appropriate habitat (such as silty, lowland rivers). The density of the species is also considered to vary between islands; field surveys indicate that it is common on Guimaras and Romblon, but rarer on Negros and Cebu.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This semi-aquatic species is generally restricted to riparian vegetation present in lowland tropical moist forests (both primary and secondary) to open cultivated areas. It is probably omnivorous, and is associated with certain food trees. It appears to have a preference for particular shrubs and trees as resting places (often overhanging water), and is usually collected from these. This is an oviparous species that buries eggs within river banks.
Systems:Terrestrial; Freshwater

Threats [top]

Major Threat(s): The threats to the two species of Hydrosaurus in the Philippines are generally very similar. Populations appear to be principally threatened by habitat loss, often the conversion of wooded land to alternative uses (including agriculture), and through logging operations. In addition, animals (especially hatchlings) are heavily collected for both the pet trade (national and possibly international) and local consumption. Because of inter-island trade, there is some possibility of introduced animals mixing with indigenous populations. In some parts of is range it is additionally threatened by water pollution resulting from the use of agrochemicals and increased sedimentation.

Conservation Actions [top]

Conservation Actions: Populations have been recorded from many protected areas. There is a need to better regulate the collection of this species from the wild, as populations are generally considered to be susceptible to overharvesting. There is also a need for improved regulation to prevent contamination of waterways used by this species with agrochemicals.

Classifications [top]

14. Artificial/Terrestrial -> 14.3. Artificial/Terrestrial - Plantations
14. Artificial/Terrestrial -> 14.2. Artificial/Terrestrial - Pastureland
14. Artificial/Terrestrial -> 14.1. Artificial/Terrestrial - Arable Land
5. Wetlands (inland) -> 5.7. Wetlands (inland) - Permanent Freshwater Marshes/Pools (under 8ha)
5. Wetlands (inland) -> 5.5. Wetlands (inland) - Permanent Freshwater Lakes (over 8ha)
5. Wetlands (inland) -> 5.4. Wetlands (inland) - Bogs, Marshes, Swamps, Fens, Peatlands
5. Wetlands (inland) -> 5.1. Wetlands (inland) - Permanent Rivers/Streams/Creeks (includes waterfalls)
1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
2. Land/water management -> 2.1. Site/area management
3. Species management -> 3.1. Species management -> 3.1.1. Harvest management
3. Species management -> 3.1. Species management -> 3.1.2. Trade management

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.1. Shifting agriculture
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.2. Small-holder farming
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.1. Intentional use (species is the target)
♦ timing:Ongoing    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

9. Pollution -> 9.3. Agricultural & forestry effluents -> 9.3.4. Type Unknown/Unrecorded
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.1. Taxonomy
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
3. Monitoring -> 3.1. Population trends

♦  Food - human
 Local : ✓   National : ✓ 

♦  Pets/display animals, horticulture
 Local : ✓   National : ✓ 

Bibliography [top]

Alcala, A.C. 1986. Guide to Philippine Flora and Fauna. Natural Resources Management Center, Ministry of Natural Resources and University of the Philippines, Quezon City.

Ferner, J.W., Brown, R.M., Sison, R.V. and Kennedy, R.S. 2000. The amphibians and reptiles of Panay Island, Philippines. Asiatic Herpetological Research 9: 1-37.

IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).

Ross, C.A. and Gonzalez, P.C. 1992. Amphibians and Reptiles of Catanduanes Island, Philippines. National Museum Papers (Manila): 50-70.

Ross, C.A. and Lazell Jr., J.D. 1990. Amphibians and Reptiles of Dinagat and Siargao Islands, Philippines. Philippine Journal of Science 119(3): 256-286.

Taylor, E.H. 1922. The lizards of the Philippine Islands. Philippines Bureau of Science Publication 17: 1-269.

Citation: Ledesma, M., Brown, R., Sy, E. & Rico, E.L. 2009. Hydrosaurus pustulatus. In: The IUCN Red List of Threatened Species 2009: e.T10335A3194587. . Downloaded on 24 May 2017.
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