Palaopartula calypso 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Gastropoda Stylommatophora Partulidae

Scientific Name: Palaopartula calypso (Semper, 1865)
Common Name(s):
English Great Palau tree snail
Partula calypso Semper, 1865
Taxonomic Source(s): Slapcinsky, J and Kraus, F. 2016. Revision of Partulidae (Gastropoda, Stylommatophora) of Palau, with description of a new genus for an unusual ground-dwelling species. ZooKeys 614: 27-49 doi: 10.3897/zookeys.614.8807.
Taxonomic Notes:

Slapcinsky and Krause (2016) compared Partula calypso, P. leucothoe and P. thetis to their newly described genus and species Sphendone insolita, and to other partulids and found that these three species require their own genus because their morphology is quite different from that of true Partula and from that of all other genera. Therefore, they resurrected the genus Palaopartula Pilsbry for these three snails.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B2ab(iii); D ver 3.1
Year Published: 2016
Date Assessed: 2011-09-09
Assessor(s): O'Foighil, D. & Rundell, R.J.
Reviewer(s): Cowie, R., Barker, G., Triantis, K., García, N. & Pippard, H.
This is an amended version of the 2011 assessment to revise the genus name for this species and to update the taxonomic notes.

This species is known from two locations on two different islands in Palau: Babaldaob and Koror, both of which are amongst the most heavily modified in the archipelago. The species is listed as Critically Endangered. It has a very small area of occupancy, it is severely fragmented, and there is a continuing decline in the quality and extent of its habitat, due to habitat modification and the introduction of predators. Only two individuals have been recorded in recent surveys.  Field work to define the current distribution of this species is required, as well as research on its population status and trends.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to Palau. There are two sources available: Y. Kondo's unpublished Ph.D. thesis reflecting sampling done in 1936, and also unpublished data from recent extensive land snail surveys (2003, 2005, 2007 and 2010) performed by R. Rundell. Kondo (1955) states that this species was relatively rare (four specimens in the Bishop Museum collection relative to 170 of P. thetis) and he recorded it from "only two distantly separated localities". Kondo's two localities were Ngatpang on the island of Babeldaob and the island of Koror (Oreor) (R. Rundell pers. comm). Rundell encountered this species in two locations in 2003: one live subadult on the Island of Babeldaob (Airai State; Oikull) "area adjacent to grassy area and near limestone rock path; palms, coconut trees, high canopy, next to large limestone boulders", and one live adult on the Island of Koror: Ngerbechedesau limestone ridge, "gate to Etpison house; on leaves and limestone". This specimen has the Field Museum of Natural History of Chicago number FMNH310532. It was forwarded to D. O'Foighil for genotyping, then passed on to B. Clarke (University of Nottingham).

Countries occurrence:
Additional data:
Estimated area of occupancy (AOO) - km2:1Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:349
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:2Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):2
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:During unpublished surveys carried out by R. Rundell (2003, 2005, 2007 and 2010) only one live subadult on the island of Babeldaob and one live adult on the island of Oreor were recorded.
Current Population Trend:Unknown
Additional data:
Number of mature individuals:1-49
Extreme fluctuations:NoPopulation severely fragmented:Yes
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:This species is arboreal and also found on emergent vegetation.
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):0-3
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: There are no reports of the species being used or traded by humans. However, limited trade may exist among shell collectors, since this species is one of the few remaining representatives of the charismatic, large-bodied land snails of Oceania. Such trade should be strongly monitored, given the threat status of this species.

Threats [top]

Major Threat(s): The localities where this species occurs are low elevation areas near permanent human habitation and are susceptible to land modification.

Rats such as Rattus norvegicus (Norway Rat), Rattus rattus (Ship Rat), and Rattus exulans (Polynesian Rat) represent a threat to the species. These species can be introduced and repeatedly re-introduced (by boat) by humans, but can also cross water independently. There are no known indigenous predatory land snails in Palau, and indigenous Palau species have evolved in the absence of such predation pressures. Euglandina rosea (Spiraxidae), Gonaxis kibweziensis and Gulella bicolor (Streptaxidae) have been introduced to Palau within the past 100 years (Cowie et al. 1996), and throughout the Pacific. Euglandina rosea and Gonaxis spp. in particular have been introduced in ill-conceived attempts at biocontrol for Achatina fulica (Meyer et al. 2008). Of these non-indigenous predatory species, Gulella bicolor was found by Cowie (Cowie et al. 1996) and Rundell (R.J. Rundell unpublished data, 2003, 2005, 2007).  Although Euglandina rosea was not found, the presence of Achatina fulica (an agricultural pest) in Palau, particularly on the islands of Koror and Babeldaob (RJ Rundell, unpublished data, 2003, 2005, 2007) means that agricultural areas on these islands (e.g. Airai State) may be subject to renewed biocontrol attempts in the future, and vigilance is necessary regarding the potentially devastating consequences of E. rosea re-introductions. Note that accidental introductions (and distribution to different localities) are likely as a result of transportation of soil and organic debris (where snail eggs may be present), plants and produce.

Conservation Actions [top]

Conservation Actions:

Field work to define the current distribution of this species, as well as research on its population status and trends, is required. Identification of priority sites for species conservation (e.g. key biodiversity areas that include threatened land snails) and reducing the impacts of human activities, especially on the small islands, is also urgently needed. The Palau Conservation Society has been supportive of recent land snail survey work in Palau. This species would benefit from protection of the forest patches in which it lives, as well as periodic monitoring. Captive breeding, preferably on Palau, should also be considered. Continued biosecurity vigilance is critically needed to prevent Rosy Wolf Snail and Platydemus manokwari establishment.

Citation: O'Foighil, D. & Rundell, R.J. 2016. Palaopartula calypso. The IUCN Red List of Threatened Species 2016: e.T16285A103138894. . Downloaded on 27 April 2018.
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