The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Thiara scabra
Thiara scabra
(Pagoda tiara)
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Thiara scabra (Muller, 1774)

Common name: Pagoda tiara

Size: 20 mm in shell height (Thompson et al., 2009)

Native Range: South and Southeast Asia and Indo-Australian Archipelago and western Pacific Islands (Brandt, 1974 as cited in Thompson et al., 2009).

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Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Thiara scabra are found here.

StateYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Florida200620184Big Cypress Swamp; Caloosahatchee; Everglades; Florida Southeast Coast

Table last updated 5/25/2018

† Populations may not be currently present.

Ecology: This snail lives in freshwater streams (Maciolek and Ford, 1987) and coastal brackish waters (Sri-aroon et al., 2004).

Reproduction is parthenogenic (Thompson et al., 2009). Embryos develop in a brood pouch to a shelled juvenile and are fed by a yolk sac and a placenta-like epithelium in the brood pouch (Glaubrecht, 2006). They have few young, but are well developed when they hatch (Glaubrecht, 2006).

Means of Introduction: Because of its relatively small size and ornate shell, it is probably an aquarium trade introduction (Thompson et al., 2009).

Status: Unknown, however, none were found at one previously infested site in 2008.

Impact of Introduction: Unknown, however, this species is susceptible, albeit at a low rate of 1.2 percent, to trematode infections in Thailand (Dechruksa et al., 2007).

Remarks: Because of its mode of reproduction, a single specimen can start a population (Thompson et al., 2009).

References: (click for full references)

Brandt, R.A.M. 1974. The non-marine aquatic Mollusca of Thailand. Archiv für Molluskenkunde 105:1-423.

Dechruksa, W., D. Krailas, S. Ukong, W. Inkapatanakul, and T. Koonchornboon. 2007. Trematode infections of the freshwater snail family Thiaridae in the Khek River, Thailand. Southeast Asian Journal of Tropical Medicine and Public Health 38(6):1016-1028.

Glaubrecht, M. 2006. Independent evolution of reproductive modes in viviparous freshwater Cerithioidea (Gastropoda, Sorbeoconcha) - a brief review. Basteria Supplement 3:23-28.

Maciolek, J.A. and J.I. Ford. 1987. Macrofauna and environment of the Nanpil-Kiepw River, Ponape, Eastern Caroline Islands. Bulletin of Marine Science 41(2):623-632.

Thompson, F.G., M.W. Heyn, and D.N. Campbell. 2009. Thiara scabra (O. F. Mueller, 1774): the introduction of another Asian freshwater snail into the United States. The Nautilus 123(1):21-22.

Author: Benson, A.J.

Revision Date: 6/3/2013

Citation Information:
Benson, A.J., 2018, Thiara scabra (Muller, 1774): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=2644, Revision Date: 6/3/2013, Access Date: 5/26/2018

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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URL: https://nas.er.usgs.gov
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Page Last Modified: Wednesday, May 23, 2018


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [5/26/2018].

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