Epitoniidae Berry, 1910 (1812)

Epitonium irregulare

(Sowerby II, 1844)

Description:

Dimensions range from 6 mm - 30.8 mm high and 3.5 mm - 11.2 mm wide.
Width to height ratio: 0.58:1 ~ 0.36:1

Shell: ventricose, pointed, pyramidal; thin fragile; minute to moderately small. Exterior colour white. About 12 whorls, rounded, contiguous; protoconch with ~3 whorls usually missing in adult specimens; teleoconch with 9 whorls rounded, increasing gradually. Spire pyramidally elevated. Suture deep and slightly fenestrated, channelled near the suture. Umbilicate: narrow, distinctly perforated, partly covered by the reflected columellar margin. Approximately 38 costae on the body whorl. Costae are very thin, numerous, irregular. Costae aligned; slightly coronated at the shoulder; standing out slightly at the suture; contiguous, contiguous across the whorls. Intercostal spaces crossed by minute spiral striae. Columella thin, sinuous. Aperture sub-ovate; peristome thin, complete; outer lip margin roundly arcuate; inner lip oblique.

Distribution:

Southern Japan; Philippines [Nakayama, 2003:73]; Taiwan [Huang & Lee, 2016:19]; Andaman Sea, Thailand [Wells et al., 2021:128]; Brazier [1875: 249] also reported specimens from Torres Strait

Habitat:

15 m [Higo et al., 1999]; coral and sand [Brazier, 1875:249]

Type Material:

Catanauan, pr. Tayabas, Luzon Island, Philippines for Epitonium irregulare (Sowerby II, 1844). [Nakayama, T., 2003]
Off Esuzaki, Kii Peninsula, Japan, at about 150 m deep [as Epitonium virgo (Masahito & Habe, 1976)]. [Nakayama, T., 2003]
NHMUK 1966402 (syntypes). [as Scalaria irregularis G.B. Sowerby II, 1844:] - Type Locality: Catanuan, Luzon, Philippines.. [Brown, L. & Neville, B.D., 2015]
not located. [as Scalaria undulatissima G.B. Sowerby II, 1874:] - Type Locality: none given.. [Brown, L. & Neville, B.D., 2015]
Holotype : NSMIT-Mo 52446 [as Foliaceiscala virgo Masahito & T. Habe, 1976] - Type Locality: off Esuzaki (cape), Wakayama prefecture (Kii peninsula, central Honshs

SpeciesImage

Murrell, T. (2023).

Mactan Island, Cebu, Philippines
on mushroom coral at 3-5 m
30.8mm

Distribution

as listed in source literature

Reeve, L.A. (1873).

Shown in text as Scalaria irregularis

Species Image

Plate xxxiii. Fig. 40.

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Plate xxxiii. Fig. 60.

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pp: 90.

Reeve, L.A. (1873).

Shown in text as Scalaria undulatissima G. B. Sowerby II, 1874

Species Image

Plate xiv. Fig. 121a.

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Plate xiv. Fig. 121ab.

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Reeve, L.A. (1873).

Shown in text as Scalaria irregularis G. B. Sowerby II, 1844

Species Image

Plate iv. Fig. 26.

Species Image

Shell white, thin, umbilicate, pyramidal; whorls rounded, contiguous; varices very slender, numerous, irregular, slightly projecting at the suture; inner lip oblique.

Tryon, G.W. (1887).

Shown in text as Scalaria undulatissima G. B. Sowerby II, 1874

Species Image

Plate 12. Fig. 70.

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pp: 60.

Tryon, G.W. (1887).

Shown in text as Scalaria irregularis G. B. Sowerby II, 1844

Species Image

Plate 12. Fig. 71.

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pp: 60.

Clessin, S. (1897).

Shown in text as Scalaria undulatissima G. B. Sowerby II, 1874

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Plate 7. Fig. 4.

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pp: 26-27.

Shell white, thin, pyramidal, perforated, spirally very finely striated; approximately nine whorls increasing rather rapidly, canaliculated at the suture; varices unequal, thin, only rarely thicker, neatly undulate, aculeate (spiny) near the suture; umbilicus small; aperture subovate, columellar margin thin and sinuate, outer margin crenulated above, aculeate near the suture.

Clessin, S. (1897).

Shown in text as Scalaria irregularis G. B. Sowerby II, 1844

Species Image

Plate 9. Fig. 9.

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pp: 33.

Shell white, thin, umbilicated, pyramidal; whorls rounded, contiguous; varices extremely delicate, numerous, irregular, slightly projecting at the suture; inner lip oblique.

Kaicher, S.D. (1980).

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Card #: EP1-2310.

BMNH type collection 1966402

Nakayama, T. (2003).

Shown in text as Epitonium virgo (Masahito & Habe, 1976)

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pp: 139. Plate 18. Fig. 14-16.

figs 14-16:
Epitonium (Limiscala) virgo (Masahito & Habe, 1976)
height 22.0 mm; breadth 11.2 m (holotype); fig. 16, base

Nakayama, T. (2003).

Species Image

pp: 139187-9.

figs 7-9:
Epitonium (Papyriscala) irregulare (Sowerby, 1844)
height 6.0 mm; breadth 3.5 m (KC); fig. 9, base

Kokshoorn, B., Gittenberger, J. & Gittenberger, A (2007).

Species Image

pp: 39. Fig. 17-18.

17-18,E.irregulare
(Sowerby[II],1844),syntypes(BMNH1966402),resp.H=12.3mm andH=9.5mm.

Murrell, T. (2023).

Species Image

Mactan Island, Cebu, Philippines
on mushroom coral at 3-5 m
30.8mm

Species Image

Synonymy:

Epitonium virgo (Masahito & Habe, 1976) [in Nakayama, T., 2003].
Foliaceiscala virgo Masahito & T. Habe, 1976 [in Higo, S., Callomon, P. & Goto, Y., 1999].
Foliaceiscala virgo Masahito & T. Habe, 1976 [in Higo, S., Callomon, P. & Goto, Y., 2001].
Limiscala irregulare (G. B. Sowerby II 1844) [in Huang, C. W. & Lee, Y.C., 2016].
Scalaria irregularis [in Sowerby, G. B. II., 1844].
Scalaria irregularis G. B. Sowerby II, 1844 [in Clessin, S., 1897].
Scalaria irregularis G. B. Sowerby II, 1844 [in Reeve, L.A., 1873].
Scalaria irregularis G. B. Sowerby II, 1844 [in Tryon, G.W., 1887].
Scalaria irregularis G.B. Sowerby II, 1844: [in Brown, L. & Neville, B.D., 2015].
Scalaria undulatissima G. B. Sowerby II, 1874 [in Clessin, S., 1897].
Scalaria undulatissima G. B. Sowerby II, 1874 [in Reeve, L.A., 1873].
Scalaria undulatissima G. B. Sowerby II, 1874 [in Tryon, G.W., 1887].
Scalaria undulatissima G.B. Sowerby II, 1874: [in Brown, L. & Neville, B.D., 2015].

Source Literature:

Brazier, J. (1875). Shells collected during the Chevert Expedition, with Descriptions of the New Species. Proceedings of the Linnean Society of New South Wales. 1(3). Linnean Society of New South Wales.. https://www.biodiversitylibrary.org/item/22887 [Accessed 3 September 2025]
Brown, L. & Neville, B.D. (2015). Catalog of the recent taxa of the families Epitoniidae and Nystiellidae (Mollusca: Gastropoda) with a bibliography of the descriptive and systematic literature. Zootaxa. 3907(1). Magnolia Press Auckland, New Zealand. http://dx.doi.org/10.11646/zootaxa.3907.1.1 [Accessed 22 October 2023]
Clessin, S. (1897). Die Familie der Scalariidae. In W. Kobelt (Ed.), Systematisches Conchylien-Cabinet von Martini und Chemnitz. Neu herausgegeben und vervollständigt. 2(13). Bauer & Raspe, NürnbergBauer & Raspe, Nürnberg. https://www.biodiversitylibrary.org/page/34259905 [Accessed 21 June 2025]
Higo, S., Callomon, P. & Goto, Y. (1999). Catalogue and Bibliography of the Marine Shell-Bearing Mollusca of Japan.. https://www.researchgate.net/publication/266375656_Catalogue_and_Bibliography_of_the_Marine_Shell-Bearing_Mollusca_of_Japan [Accessed 25 July 2025]
Higo, S., Callomon, P. & Goto, Y. (2001). Catalogue and Bibliography of the Marine Shell-Bearing Molluscs of Japan. Type Figures. Elle Scientific Publications
Huang, C. W. & Lee, Y.C. (2016). Checklist of the family Epitoniidae (Mollusca: Gastropoda) in Taiwan with description of a new species and some new records. Biodiversity Data Journal. 4. doi: 10.3897/ BDJ.4.e5653 [Accessed 25 August 2023]
Kaicher, S.D. (1980). Epitoniidae I [Pack 23]. S. D. Kaicher, St. Petersburg, Florida. http://www.femorale.com/kaicher/species.asp?f=Epitoniidae&c=125 [Accessed 8 May 2023]
Kokshoorn, B., Gittenberger, J. & Gittenberger, A (2007). Epitoniid parasites (Gastropoda, Caenogastropoda, Epitoniidae) and their host sea anemones (Cnidaria,Actiniaria,Ceriantharia) in the Spermonde archipelago, Sulawesi, Indonesia. Basteria. 71(1-3)
Murrell, T. (2023). personal description
Nakayama, T. (2003). A Review of Northwest Pacific Epitoniids. Monographs of Marine Mollusca. 6. Backhuys Publishers
Reeve, L.A. (1873). Monograph of the genus Scalaria. Conchologia iconica, or illustrations of the shells of molluscous animal. 19. London. https://www.biodiversitylibrary.org/page/8217819 [Accessed 24 August 2023]
Sowerby, G. B. II. (1844). Monograph of the genus Scalaria.. Thesaurus conchyliorum, or monographs of genera of shells.. 1 (4). London, privately published.. http://biodiversitylibrary.org/page/11076419 [Accessed 22 June 2023]
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]
Weil, A., Brown, L. & Neville, B. (1999). The Wentletrap Book. Evolver
Wells, E., Sanpanich, K., Tan, S. K, & Duangdee, T. (2021). The Marine and Estuarine Molluscs of Thailand. Lee Kong Chian natural History Museum
WoRMS Editorial Board (2025). World Register of Marine Species. https://www.marinespecies.org [Accessed 8 November 2025]

WoRMS direct page link: Open WoRMS record