Janthina exigua

Lamarck, 1816

Description:

Dimensions range from 6 mm - 20 mm high and 5 mm - 15.5 mm wide.
Width to height ratio: 0.83:1 ~ 0.78:1

Shell: globose, ovate-conical; thin, fragile; minute to small. Exterior colour violet, paler near the sutures., darker in the smaller specimens. About 5 whorls, rounded, with chevron-shaped growth striae following the shape of the lip sinus. Spire elevated, apex sharp. Suture very deeply impressed. Umbilicate: very narrow, partially covered by a thin columellar callus. Intercostal spaces with chevron-shaped growth striae following the shape of the lip sinus. Columella straight, smooth, slightly reflected. Aperture more than half of shell length, angular, somewhat ovate; outer lip thin, with a central, sharp, angular, v-shaped sinus. Operculum not present.

Distribution:

Worldwide, in tropical and temperate seas, including southern Australian states NSW to WA including Tasmania; New Zealand [Beechey, 2008]; New Caledonia [Montrouzier, 1860:114]; Norfolk Island, Lord Howe Island, Kemandec Islands, Chatham Islands, New Zealand [Beu, 2017: 123]; Singapre [Tan & Woo, 2010:40]; Korean Peninsular [NIBR, 2019:328]; Florida Keys to Brazil and entire Gulf of Mexico [Rosenberg et al, 2009:643]; State of Rio Grande du Sol, Brazil [Rios 1985:160], Rochebrune & Mabille (1889, p. 45) record Janthina courcelli R. & M. from Orange Bay, Tierra del Fuego.[Powell, 1960:142]; Hawaii, California, West coast Chile, Madeira, Reunion [Tryon, 1887]; Mediterranean Spain [Gofas et al., 2011:208].

Habitat:

pelagic, found washed up on beaches.

Etymology:

[latin] from exiguus = small, slight or insignificant, in relation to the small size of the shell.

Reeve, L. A. (1858). Plate V. Fig. 25b.

Distribution

as listed in source literature

Type Material:

The following list brings together type material and other cited specimens as reported in the sources examined, grouped under the names and designations used in each source. The same specimen may appear in multiple entries drawn from different sources. Some entries concern other species included by authors for comparison; inclusion in this list does not imply synonymy.

Janthina exigua Lamarck, 1816SyntypeMHNG 1094/80 now catalogued as MHNG-INVE51377. [3 specimens]. [Beu, 2017: 123].
Janthina bifida Reeve, 1858Syntype [possible]LIVCM.1957.62 [190]. no locality available, [Ablett J. et al., 2019: LIVCM.1957.62 [190]].
Janthina capreolata Montrouzier, 1859TypeMHNB. [4 specimens]. [Montrouzier, 1860: 114].

Lamarck, J. B. P. A. de M. de (1816).

Plate 456. Fig. 2a-b.

Orbigny, A. D. d' (1841).

pp: 414.

Reeve, L. A. (1858).

Shown in text as Ianthina bifida Reeve, 1858

Plate V. Fig. 25a.

Shell turbinate, with an acuminately conical spire; whorls rounded, somewhat narrow, densely striated with concentric lamellae, the striae in the middle very obliquely sinuated; intensely violet; columella delicately reflexed, arched; aperture small, deeply notched.

Plate V. Fig. 25b.

Reeve, L. A. (1858).

Plate V. Fig. 21a.

Plate V. Fig. 21b.

Shell conical-turbinate, with an elevated spire, impressed sutures, and a sharp apex; whorls rounded, concentrically lamellate-wrinkled, with folds sinuous in the middle; deep violet, translucent; columella rather short, slightly reflexed; aperture small, notched in the middle.

Montrouzier, R.P (1860).

Shown in text as Janthina capreolata Montrouzier, 1859

Plate II. Fig. 4.

pp: 114.

Tryon, G.W. (1887).

Shown in text as Janthina capreolata Montrouzier, 1859, Janthina vinsoni Deshayes, 1863, Ianthina bifida Reeve, 1858

Plate 10. Fig. 18-19, 22.

Fig 18 Janthina capreolata Montrouzier, 1859
fig 29 Ianthina bifida Reeve, 1858

Plate 10. Fig. 17, 20-21.

fig 20 Janthina vinsoni Deshayes, 1863

pp: 37-38.

Macpherson, J.H. & Gabriel, C.J. (1962).

pp: 121. Fig. 146.

pp: 119.

Beu, A. G. (2017).

pp: 123. Plate 2. Fig. M.

GNS RM5626
Nukumaru Beach, Whanganui, New Zealand.

pp: 123. Plate 2. Fig. O.

GNS RM5626
Nukumaru Beach, Whanganui, New Zealand.

Synonymy:

Ianthina bifida Reeve, 1858 [Reeve, 1858: nd]
Janthina bifida Reeve, 1858 [Ablett J. et al., 2019: LIVCM.1957.62 [190]]
Janthina capreolata Montrouzier, 1859 [Tryon, 1887: 37; Montrouzier, 1860: 114]
Janthina courcellei Mabille & Rochebrune, 1889 [Powell, 1960: 142]

Source Literature:

Ablett J., Brown C., Gallichan J., Gordon D., Holmes A. M., Hunter T., Machin R., Morgenroth H., Oliver P. G., Petts R., Pye S., Reilly M., Rowson B., Salvador A., Sutcliffe R., Turner, J. A. & Wood H. (2019). Mollusca Types in Britain & Ireland. https://gbmolluscatypes.ac.uk [Accessed 31 March 2026]
Alf, A., Brenzinger, B., Haszprunar, G., Schrödl, M. & Schwabe, E. (2020). A Guide to Marine Molluscs of Europe. Conch Books. Conch Books
Beechey, D. (2008r). Janthina_exigua. Seashells of NSW. https://seashellsofnsw.org.au/Janthinidae/Pages/Janthina_exigua.htm [Accessed 10 May 2023]
Beu, A. G. (2017). Evolution of Janthina and Recluzia. Records of the Australian Museum. 69(3). The Australian Museum. 10.3853/j.2201-4349.69.2017.1666 [Accessed 6 December 2023]
Gershwin, L., Sutton, C., Gowlett-Holmes, K., and Kloser, R (2018). The Pelagic Snails.. In: Pelagic Invertebrates of the Tasman Sea and Great Australian Bight: A practical field guide.. CSIRO Oceans and Atmosphere: Hobart.
Gofras, S., Moreno, D., & Salas, C. (2011). Moluscos Marinos de Andalucia I. 1. Servicio de Publicaciones e Intercambio Científico, Universidad de Málaga: Málaga.. https://www.researchgate.net/profile/S-Gofas/publication/269702794_Moluscos_marinos_de_Andalucia_Volumen_I_pp_i-xvi_y_1-342_Volumen_II_pp_i-xii_y_34-809_preview_of_Table_of_Contents_and_of_selected_chapters/links/5493e8210cf25de74db505cd/Moluscos-marinos-de-Andalucia-Volumen-I-pp-i-xvi-y-1-342-Volumen-II-pp-i-xii-y-343-809-preview-of-Table-of-Contents-and-of-selected-chapters.pdf [Accessed 1 March 2026]
Lamarck, J. B. P. A. de M. de (1816). Mollusques et polypes divers.. Tableau encyclopédique et méthodique des trois règnes de la nature,. 23. https://www.biodiversitylibrary.org/page/37162278#page/165/mode/1up [Accessed 13 June 2025]
Macpherson, J.H. & Gabriel, C.J. (1962). Marine Molluscs of Victoria. Melbourne University Press and National Museum of Victoria: Melbourne.. https://archive.org/details/marinemolluscsof0000jhop/page/118/mode/2up [Accessed 13 June 2025]
Manousis, T. (2021). The Marine Mollusca of Greece: an up-to-date, systematic catalogue, documented with bibliographic and pictorial references. Xenophora Taxonomy. 34
Montrouzier, R.P (1860). Descriptions d'espèces nouvelles de l'Archipel Calédonien (3e article). Journal de Conchyliologie. 8
NIBR National Institute of Biological Resources, (2019). National Species List of Korea II. Vertebrates · Invertebrates · Protozoa. National Institute of Biological Resources.
Orbigny, A. D. d' (1841). Voyage dans l'Amérique méridionale. Voyage dans l'Amérique méridionale. 5(3). https://www.biodiversitylibrary.org/page/49211253 [Accessed 17 March 2025]
Pilsbry, H. A. & Lowe, H. N. (1932). West Mexican and Central American Mollusks Collected by H. N. Lowe, 1929-31. Proceedings of the Academy of Natural Sciences of Philadelphia. 84. http://www.jstor.org/stable/4064126 [Accessed 21 October 2025]
Powell, A. W. B. (1960). Antarctic and Subantarctic Mollusca. Records of the Auckland Institute and Museum. 5(3/4). Auckland War Memorial Museum. https://www.jstor.org/stable/42906097 [Accessed 1 November 2025]
Reeve, L. A. (1858). Monograph of the genus Ianthina. In: Conchologia Iconica, or, illustrations of the shells of molluscous animals. 11. L. Reeve & Co., London.. https://www.biodiversitylibrary.org/page/8183142 [Accessed 12 July 2025]
Rios, E. de C. (1985). Seashells of Brazil. Fundação Universidade do Rio Grande.
Rosenberg, G., Moretzsohn, F. & García, E. (2009). Gastropoda (Mollusca) of the Gulf of Mexico. Gulf of Mexico: Its Origins, Waters, and Biota.Vol 1: Biodiversity. D. L. Felder & D. K. Camp, eds,. Texas A & M University Press
Tan, S. K. & Woo, H. P. M. (2010). A preliminary checklist of the molluscs of Singapore. Raffles Museum of Biodiversity Research & Department of Biological Sciences, National University of Singapore.
Tryon, G.W. (1887). Manual of conchology, structural and systematic with illustrations of the species. IX. Academy of Natural Sciences. https://www.biodiversitylibrary.org/page/11026889 [Accessed 20 September 2025]
Wilson, B.R. (1993). Australian Marine Shells. Australian Marine Shells. Vol.1. Odessey Publications
WoRMS Editorial Board (2025). World Register of Marine Species. https://www.marinespecies.org at VLIZ. [Accessed 8 November 2025]

WoRMS direct page link: Open WoRMS record

Janthina exigua

Lamarck, 1816

Description:

Distribution:

Habitat:

pelagic, found washed up on beaches.

Etymology:

[latin] from exiguus = small, slight or insignificant, in relation to the small size of the shell.

Distribution

Type Material:

Lamarck, J. B. P. A. de M. de (1816).

Plate 456. Fig. 2a-b.

Orbigny, A. D. d' (1841).

pp: 414.

Reeve, L. A. (1858).

Shown in text as Ianthina bifida Reeve, 1858

Plate V. Fig. 25a.

Shell turbinate, with an acuminately conical spire; whorls rounded, somewhat narrow, densely striated with concentric lamellae, the striae in the middle very obliquely sinuated; intensely violet; columella delicately reflexed, arched; aperture small, deeply notched.

Plate V. Fig. 25b.

Reeve, L. A. (1858).

Plate V. Fig. 21a.

Plate V. Fig. 21b.

Shell conical-turbinate, with an elevated spire, impressed sutures, and a sharp apex; whorls rounded, concentrically lamellate-wrinkled, with folds sinuous in the middle; deep violet, translucent; columella rather short, slightly reflexed; aperture small, notched in the middle.

Montrouzier, R.P (1860).

Shown in text as Janthina capreolata Montrouzier, 1859

Plate II. Fig. 4.

pp: 114.

Tryon, G.W. (1887).

Shown in text as Janthina capreolata Montrouzier, 1859, Janthina vinsoni Deshayes, 1863, Ianthina bifida Reeve, 1858

Plate 10. Fig. 18-19, 22.

Fig 18 Janthina capreolata Montrouzier, 1859 fig 29 Ianthina bifida Reeve, 1858

Plate 10. Fig. 17, 20-21.

fig 20 Janthina vinsoni Deshayes, 1863

pp: 37-38.

Macpherson, J.H. & Gabriel, C.J. (1962).

pp: 121. Fig. 146.

pp: 119.

Beu, A. G. (2017).

pp: 123. Plate 2. Fig. M.

GNS RM5626 Nukumaru Beach, Whanganui, New Zealand.

pp: 123. Plate 2. Fig. O.

GNS RM5626 Nukumaru Beach, Whanganui, New Zealand.

Synonymy:

Ianthina bifida Reeve, 1858 [Reeve, 1858: nd]Janthina bifida Reeve, 1858 [Ablett J. et al., 2019: LIVCM.1957.62 [190]]Janthina capreolata Montrouzier, 1859 [Tryon, 1887: 37; Montrouzier, 1860: 114]Janthina courcellei Mabille & Rochebrune, 1889 [Powell, 1960: 142]

Source Literature:

WoRMS direct page link: Open WoRMS record

Fig 18 Janthina capreolata Montrouzier, 1859
fig 29 Ianthina bifida Reeve, 1858

GNS RM5626
Nukumaru Beach, Whanganui, New Zealand.

GNS RM5626
Nukumaru Beach, Whanganui, New Zealand.

Ianthina bifida Reeve, 1858 [Reeve, 1858: nd]
Janthina bifida Reeve, 1858 [Ablett J. et al., 2019: LIVCM.1957.62 [190]]
Janthina capreolata Montrouzier, 1859 [Tryon, 1887: 37; Montrouzier, 1860: 114]
Janthina courcellei Mabille & Rochebrune, 1889 [Powell, 1960: 142]