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Plicate rocksnail

The plicate rocksnail, scientific name Leptoxis plicata, is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Pleuroceridae.

Plicate rocksnail
1842 drawing of the shell of Leptoxis plicata by Jean-Charles Chenu.
Scientific classification
Kingdom:
Phylum:
Class:
(unranked):
Superfamily:
Family:
Genus:
Species:
L. plicata
Binomial name
Leptoxis plicata
Conrad, 1834[2]
Synonyms

Anculotus plicatus Conrad, 1834 Anculotus plicata Conrad

This species is endemic to the United States, specifically the state of Alabama. The snail has been listed as endangered on the United States Fish and Wildlife Service list of endangered species since October 28, 1998.[3]

1842 drawing of a green shell Leptoxis plicata.
Drawing of abaperural view of the shell of Leptoxis plicata by Timothy Abbott Conrad.

Description

The plicate rocksnail is a pleurocerid snail with a shell that grows to about 20 mm (0.8 in) in length. Shells are subglobose with broadly rounded apertures. The body whorl may be ornamented with strong folds or plicae. Shell color is usually brown, occasionally green, and often with four equidistant color bands. The columella (central column or axis) is smooth, rounded, and typically pigmented in the upper half. The aperture is usually bluish-white, occasionally pink or white.[4]

The operculum (plate that closes the shell when the snail is retracted) is dark red, and moderately thick.[4][5]

Although morphologically similar to the basin's other three surviving rocksnail species, the plicate rocksnail is genetically distinct.[4][6]

Distribution

The plicate rocksnail historically occurred in the Black Warrior River, the Little Warrior River, and the Tombigbee River.[4][5]

Recent status surveys have located plicate rocksnail populations only in an approximately 88 km (55 mi) reach of the Locust Fork of the Black Warrior River, Jefferson and Blount counties, Alabama.[7] The latest survey information indicates that the snail has recently disappeared from the upstream two-thirds portion of that habitat and now appears to be restricted to an approximately 32 km (20 mi) reach in Jefferson County.[4][8][9]

Reasons for the decline

The plicate rocksnail has disappeared from more than 90 percent of its historic range. The curtailment of habitat and range for this species (and a few other snail species) in the Mobile Basin's larger rivers – (Black Warrior River, the Little Warrior River, and the Tombigbee River for the plicate rocksnail) is primarily due to extensive construction of dams, and the subsequent inundation of the snail's shoal habitats by the impounded waters. This snail has disappeared from all portions of its historic habitats that have been impounded by dams.[4]

Dams change such areas by eliminating or reducing currents, and thus allowing sediments to accumulate on inundated channel habitats. Impounded waters also experience changes in water chemistry, which could affect survival or reproduction of riverine snails. For example, many reservoirs in the Basin currently experience eutrophic (enrichment of a water body with nutrients) conditions, and chronically low dissolved oxygen levels.[10][11] Such physical and chemical changes can affect feeding, respiration, and reproduction of these riffle and shoal snail species.[4]

Ecology

Habitat

Plicate rocksnails inhabit shallow gravel and cobble shoals in the flowing waters of rivers.[4]

Life cycle

Although the precise longevity has not been well documented, individuals have survived 2 years in captivity.[12]

References

This article incorporates public domain text (a public domain work of the United States Government) from the reference.[4]

  1. ^ Cordeiro, J.; Perez, K. (2011). "Leptoxis plicata". IUCN Red List of Threatened Species. 2011: e.T11783A3305444. doi:10.2305/IUCN.UK.2011-2.RLTS.T11783A3305444.en. Retrieved 15 November 2021.
  2. ^ Conrad T. A. 1834. New Fresh water Shells. Page 61, plate 8, figure 18.
  3. ^ Fish and Wildlife Service. (October 28) 1998. Endangered and Threatened Wildlife and Plants; Endangered Status for Three Aquatic Snails, and Threatened Status for Three Aquatic Snails in the Mobile River Basin of Alabama. Federal Register, Vol. 63, No. 208, Rules and Regulations, Accessed 26 January 2009.
  4. ^ a b c d e f g h i U.S. Fish and Wildlife Service. 2005. Recovery Plan for 6 Mobile River Basin Aquatic Snails. U.S. Fish and Wildlife Service, Jackson, Mississippi. 46 pp. pages 13-14 and page 15.
  5. ^ a b Goodrich C. 1922. The Anculosae of the Alabama River Drainage. Miscellaneous Publications, Museum of Zoology, University of Michigan (7):1-57.
  6. ^ Lydeard, Charles; Holznagel, Wallace E.; Garner, Jeff; Hartfield, Paul; Pierson, J. Malcolm (1997). "A molecular phylogeny of Mobile River drainage basin pleurocerid snails (Caenogastropoda: Cerithioidea)". Molecular Phylogenetics and Evolution. 7 (1): 117–128. doi:10.1006/mpev.1996.0377. PMID 9007026.
  7. ^ Service Field Records, Jackson, Mississippi, 1991, 1992; Malcolm Pierson, Calera, Alabama, Field Notes, 1993 in U.S. Fish and Wildlife Service. 2005. Recovery Plan for 6 Mobile River Basin Aquatic Snails. U.S. Fish and Wildlife Service, Jackson, Mississippi. 46 pp. pages 13-14.
  8. ^ Garner in litt., 1998
  9. ^ Johnson P.D. 2002. An inventory of Leptoxis plicata, the plicate rocksnail in the Locust Fork of the Black Warrior River, Jefferson County Alabama. Preliminary report to the US Fish and Wildlife Service, Jackson, MS. 22 pp.
  10. ^ Alabama Department of Environmental Management. 1994. Water quality report to Congress for calendar years 1992 and 1993. Montgomery, Alabama. 111 pp.
  11. ^ Alabama Department of Environmental Management (ADEM). 1996. Water quality report to Congress for calendar years 1994 and 1995. Montgomery, Alabama. 144 pp.
  12. ^ P. Johnson, Tennessee Aquarium Research Institute, pers. comm., 2002 in U.S. Fish and Wildlife Service. 2005. Recovery Plan for 6 Mobile River Basin Aquatic Snails. U.S. Fish and Wildlife Service, Jackson, Mississippi. 46 pp. pages 13-14.

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The plicate rocksnail scientific name Leptoxis plicata is a species of freshwater snail with a gill and an operculum an aquatic gastropod mollusk in the family Pleuroceridae Plicate rocksnail1842 drawing of the shell of Leptoxis plicata by Jean Charles Chenu Conservation statusCritically Endangered IUCN 3 1 1 Scientific classificationKingdom AnimaliaPhylum MolluscaClass Gastropoda unranked clade Caenogastropoda clade SorbeoconchaSuperfamily CerithioideaFamily PleuroceridaeGenus LeptoxisSpecies L plicataBinomial nameLeptoxis plicataConrad 1834 2 SynonymsAnculotus plicatus Conrad 1834 Anculotus plicata ConradThis species is endemic to the United States specifically the state of Alabama The snail has been listed as endangered on the United States Fish and Wildlife Service list of endangered species since October 28 1998 3 1842 drawing of a green shell Leptoxis plicata Drawing of abaperural view of the shell of Leptoxis plicata by Timothy Abbott Conrad Contents 1 Description 2 Distribution 3 Reasons for the decline 4 Ecology 4 1 Habitat 4 2 Life cycle 5 ReferencesDescription EditThe plicate rocksnail is a pleurocerid snail with a shell that grows to about 20 mm 0 8 in in length Shells are subglobose with broadly rounded apertures The body whorl may be ornamented with strong folds or plicae Shell color is usually brown occasionally green and often with four equidistant color bands The columella central column or axis is smooth rounded and typically pigmented in the upper half The aperture is usually bluish white occasionally pink or white 4 The operculum plate that closes the shell when the snail is retracted is dark red and moderately thick 4 5 Although morphologically similar to the basin s other three surviving rocksnail species the plicate rocksnail is genetically distinct 4 6 Distribution EditThe plicate rocksnail historically occurred in the Black Warrior River the Little Warrior River and the Tombigbee River 4 5 Recent status surveys have located plicate rocksnail populations only in an approximately 88 km 55 mi reach of the Locust Fork of the Black Warrior River Jefferson and Blount counties Alabama 7 The latest survey information indicates that the snail has recently disappeared from the upstream two thirds portion of that habitat and now appears to be restricted to an approximately 32 km 20 mi reach in Jefferson County 4 8 9 Reasons for the decline EditMain article Environmental impacts of dams The plicate rocksnail has disappeared from more than 90 percent of its historic range The curtailment of habitat and range for this species and a few other snail species in the Mobile Basin s larger rivers Black Warrior River the Little Warrior River and the Tombigbee River for the plicate rocksnail is primarily due to extensive construction of dams and the subsequent inundation of the snail s shoal habitats by the impounded waters This snail has disappeared from all portions of its historic habitats that have been impounded by dams 4 Dams change such areas by eliminating or reducing currents and thus allowing sediments to accumulate on inundated channel habitats Impounded waters also experience changes in water chemistry which could affect survival or reproduction of riverine snails For example many reservoirs in the Basin currently experience eutrophic enrichment of a water body with nutrients conditions and chronically low dissolved oxygen levels 10 11 Such physical and chemical changes can affect feeding respiration and reproduction of these riffle and shoal snail species 4 Ecology EditHabitat Edit Plicate rocksnails inhabit shallow gravel and cobble shoals in the flowing waters of rivers 4 Life cycle Edit Although the precise longevity has not been well documented individuals have survived 2 years in captivity 12 References EditThis article incorporates public domain text a public domain work of the United States Government from the reference 4 Cordeiro J Perez K 2011 Leptoxis plicata IUCN Red List of Threatened Species 2011 e T11783A3305444 doi 10 2305 IUCN UK 2011 2 RLTS T11783A3305444 en Retrieved 15 November 2021 Conrad T A 1834 New Fresh water Shells Page 61 plate 8 figure 18 Fish and Wildlife Service October 28 1998 Endangered and Threatened Wildlife and Plants Endangered Status for Three Aquatic Snails and Threatened Status for Three Aquatic Snails in the Mobile River Basin of Alabama Federal Register Vol 63 No 208 Rules and Regulations Accessed 26 January 2009 a b c d e f g h i U S Fish and Wildlife Service 2005 Recovery Plan for 6 Mobile River Basin Aquatic Snails U S Fish and Wildlife Service Jackson Mississippi 46 pp pages 13 14 and page 15 a b Goodrich C 1922 The Anculosae of the Alabama River Drainage Miscellaneous Publications Museum of Zoology University of Michigan 7 1 57 Lydeard Charles Holznagel Wallace E Garner Jeff Hartfield Paul Pierson J Malcolm 1997 A molecular phylogeny of Mobile River drainage basin pleurocerid snails Caenogastropoda Cerithioidea Molecular Phylogenetics and Evolution 7 1 117 128 doi 10 1006 mpev 1996 0377 PMID 9007026 Service Field Records Jackson Mississippi 1991 1992 Malcolm Pierson Calera Alabama Field Notes 1993 in U S Fish and Wildlife Service 2005 Recovery Plan for 6 Mobile River Basin Aquatic Snails U S Fish and Wildlife Service Jackson Mississippi 46 pp pages 13 14 Garner in litt 1998 Johnson P D 2002 An inventory of Leptoxis plicata the plicate rocksnail in the Locust Fork of the Black Warrior River Jefferson County Alabama Preliminary report to the US Fish and Wildlife Service Jackson MS 22 pp Alabama Department of Environmental Management 1994 Water quality report to Congress for calendar years 1992 and 1993 Montgomery Alabama 111 pp Alabama Department of Environmental Management ADEM 1996 Water quality report to Congress for calendar years 1994 and 1995 Montgomery Alabama 144 pp P Johnson Tennessee Aquarium Research Institute pers comm 2002 in U S Fish and Wildlife Service 2005 Recovery Plan for 6 Mobile River Basin Aquatic Snails U S Fish and Wildlife Service Jackson Mississippi 46 pp pages 13 14 Retrieved from https en wikipedia org w index php title Plicate rocksnail amp oldid 1055382851, wikipedia, wiki, book, books, library,

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