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Erythrolamprus ornatus 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Dipsadidae

Scientific Name: Erythrolamprus ornatus
Species Authority: (Garman, 1887)
Common Name(s):
English Ornate Ground Snake, St Lucia Racer
Synonym(s):
Dromicus ornatus Garman, 1887
Liophis ornatus (Garman, 1887)
Taxonomic Source(s): Grazziotin, F.G., Zaher, H., Murphy, R.W., Scrocchi, G., Benavides, M.A., Zhang, Y.-P. and Bonatto, S.L. 2012. Molecular phylogeny of the New World Dipsadidae (Serpentes: Colubroidea): a reappraisal. Cladistics 28(5): 437-459. DOI: 10.1111/j.1096-0031.2012.00393.x.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered D ver 3.1
Year Published: 2016
Date Assessed: 2015-07-21
Assessor(s): Daltry, J.C.
Reviewer(s): Bowles, P.
Contributor(s): Hedges, B. & Hanson, S.
Facilitator/Compiler(s): NatureServe
Justification:
Listed as Critically Endangered on the basis that this species' population almost certainly consists of fewer than 50 mature individuals. This may well be close to the maximum population size allowed by the species' current range. The snake is wholly dependent on continued conservation management for its survival, to keep Maria Major free of pest species that, if established, would rapidly drive it to extinction. Reintroduction of populations to other islands and safe enclaves on mainland Saint Lucia are likely to be necessary to render the population viable in the longer-term.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

This species is known only from Saint Lucia and the offshore island Maria Major (0.09 km2) (Henderson and Powell 2009). It is not known to occur on any other satellites nor whether it occurred there historically. It has not been recorded on Saint Lucia since mongoose were introduced in 1869 and is considered extinct on this island (Parker 1936).

Countries occurrence:
Native:
Saint Lucia
Additional data:
Upper elevation limit (metres):950
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species was considered the second most common (of five) snakes on Saint Lucia prior to its loss from this island (Underwood 1995), leaving no reasonable doubt that the failure to record it for 145 years is the result of a genuine catastrophic decline and apparent extinction. The most recent population estimate is of 18 individuals, +/- 10, based on mark-recapture data collected in 2012. This is considered unreliable due to a low number of recaptures and the species' action plan suggests, based on the frequency of sightings, a maximum population size of 106 individuals; the true population size is thought likely to be between these two extremes (Daltry and Morton 2014). These estimates include both adults and juveniles, and the population of mature adults is thought likely to be less than 50 (Daltry and Morton 2014). The population trend is unknown, however it is thought that the current population size reflects the island's carrying capacity (J. Daltry pers. comm. 2015).
Current Population Trend:Unknown
Additional data:
Number of mature individuals:8-49

Habitat and Ecology [top]

Habitat and Ecology:

On the main island of Saint Lucia, it is believed the species occupied in tropical dry and evergreen forest habitats from sea level up to 950 m asl. (the highest points of Saint Lucia). Tyler (1849) reported the Saint Lucia racer had an affinity for water and was “more frequently found in water than out of it”. The remaining population is restricted to the xeric Maria Major, which is characterized by dry forest and shrubland and has no permanent standing water. According to Ross and Williams (2012), sightings are more common following rain. The Saint Lucia racer is a ground-dwelling, diurnal snake, where it feeds on lizards (Ross and Williams 2012). Historical reports from the mainland indicate that the species fed there on mice and amphibians (Tyler 1849). It is oviparous (Tyler 1849).

Systems:Terrestrial

Use and Trade [top]

Use and Trade: There is no known use or trade in this species. Its extreme rarity (the species having been described as "the world's rarest snake" - Catterick 2012) may make it attractive to collectors.

Threats [top]

Major Threat(s): The Small Asian mongoose was introduced to Saint Lucia in the late 19th century, and this coincides with the last recorded sightings of this species on Saint Lucia. It may have been under additional pressure from other invasive species and extensive conversion of forest habitats to sugar plantations and urbanization. Until the discovery of the Maria Major population in 1973 the species was believed to be extinct.

The population on Maria Major island is at risk from inbreeding depression and stochastic events, as the maximum population size is thought most likely to be below 100. Maria Major is prone to droughts and storm surges resulting from hurricanes. Maria Major is less than 1 km from Saint Lucia, and consequently at risk from the establishment of invasive species found on the mainland, including mongoose, rats, opossums, ants, cane toads and the Puerto Rican Racer (Daltry and Morton 2014). Although no wildfires have been reported on Maria Major in recent history, fire is a high risk due to the island’s dry vegetation and unauthorized use by people. The loss of the Martinique Racer (Erythrolamprus cursor), a species that was also confined to a single small islet, suggests that this small island population is not viable in the long term (J. Daltry pers. comm. 2015).

Conservation Actions [top]

Conservation Actions: Maria Major has been within a protected area, the Maria Islands Wildlife Refuge, since 1982, and access is controlled. A species action plan has been prepared for the Saint Lucia Racer covering the years 2015-2024 (Daltry and Morton 2014). This includes recommendations for introducing a racer population to Dennery Island, another of Saint Lucia's satellites, and an examination of the feasibility of creating an invasive-free enclave on mainland Saint Lucia to which the species might be reintroduced. Continued management is required to ensure that Maria Major remains free of invasive alien species.

Citation: Daltry, J.C. 2016. Erythrolamprus ornatus. The IUCN Red List of Threatened Species 2016: e.T12080A71739705. . Downloaded on 09 December 2016.
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