Truncatella is a genus of very small land snails with an operculum, terrestrial gastropod mollusks in the family Truncatellidae. These minute snails live in land habitats close to seawater. They walk with a looping action, and the adults have truncated shells. Many of the species are small enough to be considered micromollusks.

Truncatella is the type genus of the family Truncatellidae.

Description

As implied by the name, these snails are notable for the way they modify their elongated shells as they mature, breaking off several of the apical whorls, and forming a relatively smooth seal for the remainder of the shell.

Locomotion The method of locomotion used by Truncatella is unusual.Pilsbry, H. A. & A. P. Brown (1914), The method of progression in Truncatella, Proc. Acad. Nat. Sci. Philadelphia 66: 426–428. Instead of gliding over a slime trail using minute waves in its foot, Truncatella uses a very large and muscular proboscis to reach ahead and grasp a surface, at which point the small foot releases its hold and the proboscis contracts to pull the animal forward, after which the entire procedure is usually repeated.Örstan, Aydin. How Truncatella caribaeensis moves. blog for 15 June 2006. https://snailstales.blogspot.com/2006/06/how-truncatella-caribaeensis-moves.html

Distribution and habitat This genus occurs in tropical and subtropical areas. The various species of Truncatella are pantropical in distribution, with a few exceptions such as Truncatella truncatula and Truncatella subcylindrica.

Most of the species in this genus live in a habitat that is neither fully terrestrial nor fully marine: they live under plant debris near high tide level, where they are occasionally wetted with seawater by waves. A small minority of the species are fully terrestrial.

These small snails are typically found associated with drifts of plant material, where their eggs are deposited.Ross, Landon T. (1969). Notes on the life history of Truncatella caribaeensis Reeve. American Malacological Union Ann. Rept. 1969:35-36.

The adaptations of these land snails to the terrestrial environment are not so perfect as they are in the more usual pulmonate land snails, and their terrestrial adaptations may in fact be comparatively recent.Rosenberg, Gary (1996). Independent evolution of terrestriality in Atlantic truncatellid gastropods. Evolution 50(2): 682–693.

Species

The genus Truncatella was erected by Antoine Risso (Risso, 1826) for T. costulata (now T. subcylindrica), which is the type species for this genus.

There are several genera within the Truncatellidae, but the eponymous genus Truncatella is the largest (in terms of number of species); other genera in the family are Geomelania, Taheitia, and Blandiella.Ross, Landon T. (1970). The anatomy of Truncatella Risso 1826 (Mollusca: Prosobranchia), and a revision of the genus in the Gulf of Mexico and the Caribbean Sea. unpublished Florida State Univ. dissertation. Retrieved on September 2007.Clench, William J. & Ruth D. Turner (1948), A catalogue of the family Truncatellidae with notes and descriptions of new species. Occ. Pap. Mollusks, Harvard Univ. 1: 157–212.Clench, William J. & Ruth D. Turner (1948), The genus Truncatella in the western Atlantic. Johnsonia 2: 149–164.

There are approximately 30 species in the genus Truncatella, including: † Truncatella arcicostata H.-J. Wang, 1982 Truncatella avenacea Garrett, 1887Rosenberg, G. (2010). Truncatella avenacea Garrett, 1887. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527390 on 2011-06-13 Truncatella bahamensis Clench and Turner, 1948ITIS Tuncatella bahamensis Truncatella bairdiana C. B. Adams, 1852Rosenberg, G. (2011). Truncatella bairdiana C. B. Adams, 1852. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557942 on 2011-06-13 Truncatella barbadensis L. Pfeiffer, 1857 Truncatella brazieri Cox, 1868Rosenberg, G. (2011). Truncatella brazieri Cox, 1868. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557943 on 2011-06-13 Truncatella californica Pfeiffer, 1857Rosenberg, G. (2011). Truncatella californica Pfeiffer, 1857. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557944 on 2011-06-13 - California truncatella Truncatella caribaeensis Reeve, 1842WoRMS (2010). Truncatella caribaeensis Reeve, 1842. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=419688 on 2011-06-13 - Caribbean truncatella Truncatella clathrus Lowe, 1832WoRMS (2010). Truncatella clathrus Lowe, 1832. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=419689 on 2011-06-13 † Truncatella crassolabia H.-Z. Pan, 1982 Truncatella diaphana Gassies, 1869Rosenberg, G. (2011). Truncatella diaphana Gassies, 1869. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557946 on 2011-06-13 † Truncatella directa Y.-T. Li, 1988 Truncatella granum Garrett, 1872Rosenberg, G. (2010). Truncatella granum Garrett, 1872. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527386 on 2011-06-13 Truncatella guerinii Villa & Villa, 1841Rosenberg, G. (2010). Truncatella guerinii Villa & Villa, 1841. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527391 on 2011-06-13 † Truncatella hermitei Bardin, 1879 † Truncatella hubeiensis Y.-T. Li, 1987 † Truncatella jiaozhouensis T. Yu, Salvador, H. Wang, Y. Fang, Neubauer, S. Li, H. Zang & X. Wan, 2021 Truncatella marginata Küster, 1855Rosenberg, G. (2010). Truncatella marginata Küster, 1855. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527383 on 2011-06-13 Truncatella oagariensis (Kuroda, 1960) † Truncatella obliqua H.-Z. Pan, 1982 Truncatella obscura Morelet, 1882Rosenberg, G. (2011). Truncatella obscura Morelet, 1882. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557947 on 2011-06-13 † Truncatella parva Y.-T. Li, 1988 Truncatella pfeifferi Martens, 1860Truncatella. OBIS, accessed 13 June 2011. Truncatella quadrasi Möllendorff, 1893Rosenberg, G. (2011). Truncatella quadrasi Möllendorff, 1893. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557949 on 2011-06-13 † Truncatella rabora H.-Z. Pan, 1982 Truncatella reclusa (Guppy, 1871) Truncatella rostrata Gould, 1848Rosenberg, G. (2010). Truncatella rostrata Gould, 1848. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527392 on 2011-06-13 Truncatella rustica Mousson, 1865Rosenberg, G. (2010). Truncatella rustica Mousson, 1865. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527384 on 2011-06-13 † Truncatella sanshuiensis W. Yü & X.-Q. Zhang, 1982 Truncatella scalarina Cox, 1867Rosenberg, G. (2011). Truncatella scalarina Cox, 1867. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557950 on 2011-06-13 Truncatella scalaris (Michaud, 1830)Rosenberg, G. (2010). Truncatella scalaris (Michaud, 1830). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527382 on 2011-06-13 - ladder truncatella Truncatella semperi Kobelt, 1884 † Truncatella sinensis Y.-T. Li, 1988 Truncatella stimpsonii Stearns, 1872:Rosenberg, G. (2011). Truncatella stimpsonii Stearns, 1872. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557951 on 2011-06-13 synonym of Truncatella californica L. Pfeiffer, 1857 Truncatella subcylindrica (Linnaeus, 1767)Gofas, S. (2011). Truncatella subcylindrica (Linnaeus, 1767). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=141850 on 2011-06-13 Truncatella teres (Pfeiffer, 1857): synonym of Truncatella marginata Küster, 1855 Truncatella thaanumi Clench & Turner, 1948Rosenberg, G. (2010). Truncatella thaanumi Clench & Turner, 1948. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=527387 on 2011-06-13 Truncatella truncatula J.P.R. Draparnaud, 1801: synonym of Truncatella subcylindrica (C. Linnaeus, 1767) Truncatella vincentiana Cotton, 1942 † Truncatella wattebledi Benoist, 1878 † Truncatella xuanchengensis H.-Z. Pan, 1982 Truncatella yorkensis (Cox, 1868): synonym of Truncatella guerinii A. Villa & J. B. Villa, 1841

Synonyms † Truncatella antediluviana Deshayes, 1861: synonym of † Bouryia antediluviana (Deshayes, 1861) (superseded combination) Truncatella arcasiana Crosse, 1868: synonym of Taheitia arcasiana (Crosse, 1868)(original combination) Truncatella atomus Philippi, 1841: synonym of Omalogyra atomus (Philippi, 1841) (original combination) Truncatella aurantia A. Gould, 1847: synonym of Truncatella guerinii A. Villa & J. B. Villa, 1841 † Truncatella bezanconi Cossmann, 1892: synonym of † Murchisonella bezanconi (Cossmann, 1892) (superseded combination) Truncatella bilabiata L. Pfeiffer, 1840: synonym of Truncatella pulchella L. Pfeiffer, 1839 (junior subjective synonym) Truncatella capillacea L. Pfeiffer, 1859: synonym of Truncatella pulchella L. Pfeiffer, 1839 Truncatella caribaeensis Reeve, 1842, sensu Clench & Turner, 1948: synonym of Truncatella pulchella L. Pfeiffer, 1839 (misidentification) Truncatella ceylanica Pfeiffer, 1857:Rosenberg, G. (2011). Truncatella ceylanica Pfeiffer, 1857. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=557945 on 2011-06-13 synonym of Truncatella marginata Küster, 1855 (junior synonym) Truncatella concinna Pease, 1871: synonym of Truncatella guerinii A. Villa & J. B. Villa, 1841 † Truncatella costata Cossmann, 1895: synonym of Truncatella wattebledi Benoist, 1878 (invalid; not L. Pfeiffer 1839) Truncatella costata L. Pfeiffer, 1839: synonym of Truncatella scalaris (Michaud, 1830) Truncatella costellifera Pease, 1871: synonym of Truncatella rustica Mousson, 1865 Truncatella costulata Risso, 1826: synonym of Truncatella subcylindrica (Linnaeus, 1767) Truncatella cristata Crosse, 1868: synonym of Truncatella guerinii A. Villa & J. B. Villa, 1841 Truncatella cumingii C. B. Adams, 1845: synonym of Truncatella scalaris (Michaud, 1830) † Truncatella cylindrata Briart & Cornet, 1887: synonym of † Bouryia cylindrata (Briart & Cornet, 1887) (superseded combination) Truncatella debilis Mousson, 1873: synonym of Truncatella subcylindrica (Linnaeus, 1767) Truncatella desnoyersii (Payraudeau, 1826): synonym of Truncatella subcylindrica (Linnaeus, 1767) † Truncatella distensa Cossmann, 1888: synonym of † Bouryia distensa (Cossmann, 1888) (superseded combination) Truncatella elongata L. Pfeiffer, 1856: synonym of Geomelania elongata (L. Pfeiffer, 1856) Truncatella fasciata Tapparone Canefri, 1886: synonym of Truncatella guerinii A. Villa & J. B. Villa, 1841 Truncatella ferruginea (Cox, 1868): synonym of Truncatella guerinii A. Villa & J. B. Villa, 1841 Truncatella filicosta Poey, 1858: synonym of Geomelania elongata (L. Pfeiffer, 1856) Truncatella floridana Hubricht, 1983: synonym of Truncatella pulchella L. Pfeiffer, 1839 Truncatella funiculus Mousson, 1870: synonym of Taheitia funiculus (Mousson, 1870) (original combination) Truncatella fusca Philippi, 1841: synonym of Setia fusca (Philippi, 1841)