Disclaimer:

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.

---

Common name: ghost ramshorn

Synonyms and Other Names: Biomphalaria obstructa (Morelet, 1849);  Tropicorbis havane

Taxonomy: available through www.itis.gov

Identification: Biomphalaria havanensis snails have a discoidal shape (resembling a disk) and flattened spire (Burch and Tottenham 1980). The shell is a grayish-white in color and transparent when fresh (Thompson 1999). The shell is sculptured with irregular growth striations, with adults having 5 whorls (Burch and Tottenham 1980, Thompson 1999). 

Size: Large specimens are 9-11 mm in diameter and 2.4-2.7 mm in height (Yong et al. 1997).

Native Range: The southern United States in southern Florida, central and southern Louisiana, and much of Texas (Malek 1969); Mexico and Central America (Bequaert and Miller); Puerto Rico and Cuba (Burch and Tottenham 1980). The range of this species in western Texas is not well documented, but may extend farther than this native range depicts. 

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Biomphalaria havanensis is a hermaphroditic, pulmonate (lunged) aquatic snail found on all continents (Thompson 1999, Yong et al 2001). Biomphalaria havanensis shows tolerance to a broad range of freshwater habitats and a certain degree of habitat modification (urbanization) (Vázquez Perera et al. 2010, IUCN 2019). Populations have been observed to occur with floating vegetation (e.g., duckweed, Lemna) and filamentous green algae mats (Cladophora and Pithophora; Dillon and Dutra-Clarke 1992, Dillon and colleagues 2019).

Means of Introduction: Dillon and Dutra-Clarke (1992) assumed that Biomphalaria havanensis are being introduced as hitchhikers on aquatic plants or with stocked fishes. Several aquaculture facilities have known populations of the snail (Rosser et al. 2016, Griffin et al. 2018).

In May of 2024 ramshorn snails were reported in a live crawfish shipment from Louisiana to Arkansas (personal communication, Arkansas Game and Fish Commission 2024). Another report of ramshorns from Houston, Texas was disclosed the following month (personal communication, Texas Parks and Wildlife 2024). It is believed these ramshorn snails are Biomphalaria havanensis.

Status: Established in South Carolina.

Impact of Introduction: Multiple laboratory studies have identified Biomphalaria havanensis as a moderately suitable (Brooks 1953, McQuay 1953, Rosser et al. 2016) to suitable (Cram and Files 1946, Yong et al. 2009) intermediate host for the trematode, Bolbophorus damnificus. This trematode causes significant economic losses in channel catfish (Ictalurus punctatus) aquaculture in the southeastern USA (Rosser et al 2016, Griffin et al. 2018).

Remarks: The type locality of B. havanensis is a swampy area in the vicinity of Havana, Cuba (Yong et al. 1997).

References: (click for full references)

Arkansas Game and Fish Commission. 2024. Report of ramshorn snail in live crawfish shipment to Arkansas. Personal Communication. USGS NAS Database. May 2024.

Bequaert, J.C. and W.B. Miller. 1973. The mollusks of the arid Southwest, with an Arizona checklist. The University of Arizona Press, Tucson, xvi, 271 pp.

Bowler, P.A., and T.J. Frest. 1991. The non-native snail fauna of the middle Snake River, southern Idaho. Proceedings of the Desert Fishes Council 23:28-44.

Brooks, C.P. 1953. A comparative study of Schistosoma mansoni in Tropicorbis havanensis and Australorbis glabratus. The Journal of Parasitology 39(2):159-165.

Burch, J.B., and J.L. Tottenham. 1980. North American freshwater snails: species list, ranges and illustrations. Walkerana - Transactions of the POETS Society 1(3):81-215.

Cram, E. B., and Files, V. S. 1946. Laboratory Studies on the Snail Host of Schistosoma Mansoni1. The American journal of tropical medicine and hygiene 1(5): 715-720.

Dillon, R.T. Jr. and Dutra-Clarke, A.V.C. 1992. Biomphalaria in South Carolina. Malacological Review 25:129-130.

Dillon, R. T., Jr. and colleagues. 2019.  The Freshwater Gastropods of North America Volume 1: Atlantic drainages, Georgia through Pennsylvania. http://www.fwgna.org/species/planorbidae/b_obstructa.html

Griffin, M.J., Khoo, L.H., Reichley, S.R. et al. 2018. Encapsulation of Bolbophorus damnificus (Digenea: Bolbophoridae) metacercariae in juvenile channel catfish, Ictalurus punctatus, is linked to delayed-onset mortality. Journal of World Aquaculture Society 49(3):601-611.

IUCN. 2019. The IUCN Red List of Threatened Species. Version 2019-2. https://www.iucnredlist.org

Malek, E.A. 1969. Studies on "tropicorbid" snails (Biomphalaria: Planorbdae) from the Caribbean and Gulf of Mexico areas, including the southern United States. Malacologia 7(2/3):183-209.

McQuay Jr, R. M. 1953. Studies on variability in the susceptibility of a North American snail, Tropicorbis havanensis, to infection with the Puerto Rican strain of Schistosoma mansoni. Transactions of the Royal Society of Tropical Medicine and Hygiene 47(1):56-61.

Rosser, T. G., Alberson, N. R., Khoo, L. H., Woodyard, E. T., Wise, D. J., Pote, L. M., and Griffin, M. J. 2016. Biomphalaria havanensis is a natural first intermediate host for the Trematode Bolbophorus damnificus in commercial catfish production in Mississippi. North American Journal of Aquaculture 78:189-192.

Texas Parks and Wildlife Department. 2024. Report of ramshorn snail in live crawfish shipment to Houston. Personal Communication. USGS NAS Database. June 2024.

Thompson, F.G. 1999. An identification manual for the freshwater snails of Florida. https://www.floridamuseum.ufl.edu/iz/resources/florida-snails/. Created on 07/08/2019. Accessed on 07/08/2019.

Vázquez Perera, A. A., Sánchez Noda, J., and Hevia Jiménez, Y. 2010. Distribution and habitat preferences of the genus Biomphalaria (Gastropoda: Planorbidae) in Cuba. Memórias do Instituto Oswaldo Cruz 105(1): 41-44.

Yong, M., Pointier, J.P., and Perera, G. 1997. The type locality of Biomphalaria havanensis (Pfeiffer, 1839). Malacological Review 30: 115-117.

Yong, M., Gutiérrez, A., Perera, G., Durand, P., & Pointier, J. P. "The Biomphalaria havanensis complex (Gastropoda: Planorbidae) in Cuba: a morphological and genetic study." Journal of Molluscan Studies 67.1 (2001): 103-112.

Author: Benson, A.J., Daniel, W.M., and Morningstar, C.R.

Peer Review Date: 9/27/2019

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.