Shells of Bittium reticulatum. Photo by Steve Trewhella.

Belongs within: Cerithiimorpha.

Bittium is a genus of small high-spired gastropods found primarily in cold and temperate waters in the eastern Atlantic. Like the related genus Cerithium, Bittium has been confused with other similar taxa in the past. Small Cerithium, in particular, have often been identified as Bittium but Cerithium has a single primary spiral cord on its whorls whereas Bittium has two cords apically becoming four distally. Fossils of Bittium have been recorded extending back to the Palaeocene with fossil representatives being very similar to modern species. Subgenera proposed within the genus on the basis of shell morphology may be invalid with different shell morphologies sometimes found within a single population (Houbrick 1977).

Characters (from Houbrick 1977): Shell small, turreted and elongate, consisting of many moderately inflated or angular whorls (6-10). Sculpture normally reticulate, of varying combinations of spiral cords and axial riblets, frequently beaded at intersections. Usually 3 spiral cords per whorl. Former varices usually present at irregular intervals. Suture distinct, straight. Protoconch about 2.5 whorls, smooth, but sometimes with several spiral lirations. Frequently, teleoconch strongly reticulate. Aperture ovate with short, shallow, anterior siphonal canal that is not reflected backwards. Weak anal sinus present. Columella concave and with slight callus. Outer lip thin, smooth and rounded, occasionally flaired at the base on some individuals. Base of last whorl sculptured with 5-6 spiral cords. Last whorl occasionally contracted in some individuals. Periostracum thin. Animal: Moderate sized foot with ciliated duct on right side terminating in knob-like ovipositor. Operculum thin, corneous, ovate and paucispiral with an excentric nucleus. Snout moderately large, flattened dorso-ventrally. Eyes at bases of tentacles. Mantle cavity deep with long monopectinate ctenidium extending its length, ending at anterior siphon. Osphradium bipectinate. Hypobranchial gland well-developed, large. Intestine wide, rectum distal to end of gonoduct. Feces cylindrical with mucus filament at one end. Pallial gonoducts in both sexes open, consisting of two laminae joined dorsally to mantle roof. Males aphallic, producing spermatophores about 1 mm in length containing eupyrene and apyrene spermatozoa. Eupyrene spermatozoa with nucleus about one-twentieth the total length of sperm and with spiral keel on flagellum. Female pallial oviduct a glandular groove between two deep laminae joined at dorsal wall and open ventrally. In medial lamina, an open sperm-collecting gutter runs into a ciliated tube that opens into a "bursa" at the proximal end of the medial lamina. Bursa is anterior to two seminal receptacles, the first of which serves as a receptacle for the spermatophore, in the left wall of the duct and the second along the free edge of the wall. Nervous system characterized by very large nerve ring and large cerebral ganglia. Jaws cuticular, conical and rough surfaced. Stomach with style-sac and large crystalline style. Radula taenioglossate, ribbon long, about 50 rows. Rachidian tooth squarish, concave at top with one large central cusp flanked by three denticles on each side. Base of rachidian concave with two short lateral projections. Lateral tooth rhomboidal, serrated on top with two small entocones, large pointed mesocone and four small ectocones, respectively. Base of lateral tooth with two extensions, one at each side; outer basal projection broad, long and extending laterally. Marginal teeth long, curved, spatulate and serrated at tips. Inner marginal tooth serrated with four entocones, large pointed mesocone and three sharp ectocones. Outer marginal tooth serrated with four to six entocones, outer surface smooth. Eggs tiny, deposited in gelatinous string that may be coiled counterclockwise into a spiral from 3 to 25 mm in length or irregularly folded on itself. Egg mass containing several hundred small, opaque eggs, each about 60-70 ยตm in diameter. Larvae planktotrophic with bilobed, colorless velum; right velar lobe somewhat larger than left. Larval foot colorless. Larval shell about 2.5 whorls, smooth except for median spiral ridge on second whorl. Sutures and columella reddish brown. Outer lip with prominent tongue-shaped beak.

<==Bittium Leach in Gray 1847 (see below for synonymy) H77
    |--*B. reticulatum (Costa 1778) H77 (see below for synonymy)
    |--B. adversum [=Murex adversum] H77
    |--B. alternatum D56
    |--B. armillatum Carpenter 1864 [=B. (Semibittium) armillatum] O27
    |--B. asperum Carpenter 1864 C64 [=B. (Lirobittium) asperum O27, Turbonilla aspera C64]
    |    |--B. a. asperum O27
    |    `--B. a. lomaense Bartsch 1911 [=B. (Lirobittium) asperum lomaense] O27
    |--B. attenuatum Carpenter 1864 [=B. (Semibittium) attenuatum] O27
    |    |--B. a. attenuatum O27
    |    |--B. a. boreale Bartsch 1911 [=B. (Semibittium) attenuatum boreale] O27
    |    |--B. a. latifilosum Bartsch 1911 [=B. (Semibittium) attenuatum latifilosum] O27
    |    `--B. a. multifilosum Bartsch 1907 [=B. (Semibittium) attenuatum multifilosum] O27
    |--B. cancellatum (Lamarck 1804) [=Cerithium cancellatum, *Semibittium cancellatum] H77
    |--B. caraboboense Weisbord 1962 [=B. (*Brachybittium) caraboboense] H77
    |--B. catalinensis Bartsch 1907 [=B. (*Lirobittium) catalinensis] H77
    |    |--B. c. catalinensis O27
    |    `--B. c. inornatum Bartsch 1911 [=B. (Lirobittium) catalinense inornatum] O27
    |--B. challisae Bartsch 1917 [=B. (Semibittium) challisae] O27
    |--B. chrysomallum Melville 1901 M01
    |--B. cylindricum Watson 1881 WG71
    |--B. diplax Watson 1886 H09
    |--‘Zebittium’ editum Powell 1930 P61
    |--B. elegantissimum [=Murex elegantissimum] H77
    |--B. ‘elegantissimum’ (Hedley 1899) [=Cerithium elegantissimum non Murex elegantissimum] H09
    |--B. eschrichti (Middendorff 1849) H77 (see below for synonymy)
    |    |--B. e. eschrichtii O27
    |    |--B. e. icelum Bartsch 1907 [=B. (Stylidium) eschrichti icelum] O27
    |    `--B. e. montereyense Bartsch 1907 [=B. (Stylidium) eschrichti montereyense] O27
    |--B. esuriens C64
    |--B. exile (Hutton 1873) F27 [=Cerithium exilis P61, *Zebittium exile H77]
    |--B. fastigiatum Carpenter 1864 C64
    |--B. fetellum Bartsch 1911 [=B. (Lirobittium) fetellum] O27
    |--B. granarium Kiener 1842 F27 [=Cacozelia granaria F27, Cacozeliana granarium M54]
    |--B. interfossa (Carpenter 1864) H77 [=Rissoa interfossa O27, B. (Lirobittium) interfossa O27]
    |--B. johnstonae Bartsch 1911 O27
    |--‘Cerithium’ lacertina Gould 1861 [=*Cacozelia lacertina, *Cacozeliana lacertina] H77
    |--*Inobittium’ lacteum (Philippi 1836) H77
    |--‘Zebittium’ laevicordatum Powell 1937 P61
    |--B. larum Bartsch 1911 [=B. (Lirobittium) larum] O27
    |--*Monobittium’ latreillei (Payraudeau 1826) H77
    |--B. lawleyanum Crosse 1863 F27 [=Cacozelia lawleyana F27, *Eubittium lawleyanum H77, *Parabittium lawleyanum H77]
    |--B. munitum (Carpenter 1864) [=Cerithiopsis munita, B. (Lirobittium) munitum] O27
    |    |--B. m. munitum O27
    |    `--B. m. munitoide Bartsch 1911 [=B. (Lirobittium) munitum munitoide] O27
    |--B. nitens C64
    |--B. oldroydi Bartsch 1911 [=B. (Lirobittium) oldroydi] O27
    |--B. ornatissimum Bartsch 1911 [=B. (Lirobittium) ornatissimum] O27
    |--B. paganicum Dall 1919 [=B. (Stylidium) paganicum] O27
    |--B. perparvulum Watson 1886 H09
    |--B. plicatum C64
    |--B. podagrinum Dall 1892 [=*Bittiolum podagrinum] H77
    |--B. porcellanum Watson 1886 H09
    |--B. proteum (Jousseaume 1930) BD86 [=Cerithium proteum H77; incl. *Dahlakia leilae Biggs 1971 H77]
    |--B. pupiforme Watson 1880 H09
    |--B. purpureum (Carpenter 1864) [=Cerithiopsis purpurea, B. (Semibittium) purpureum] O27
    |--B. quadrifilatum (Carpenter 1864) H77 [=B. (Semibittium) quadrifilatum O27]
    |    |--B. q. quadrifilatum O27
    |    `--B. q. ingens Bartsch 1907 [=B. (Semibittium) quadrifilatum ingens] O27
    |--B. rugatum Carpenter 1866 [=B. (Semibittium) rugatum] O27
    |--B. sanjuanensis Bartsch 1917 [=B. (Semibittium) sanjuanensis] O27
    |--B. semilaevis Tennison Woods 1877 P79
    |--B. serra Bartsch 1917 [=B. (Semibittium) serra] O27
    |--*Bittiscalia’ simplex (Marshall 1917) H77
    |--B. spenceri [=Murex spenceri] H77
    |--B. subplanatum Bartsch 1911 [=B. (Semibittium) subplanatum] O27
    |--B. tuberculare [=Murex tuberculare] H77
    |--B. tumidum Bartsch 1907 [=B. (Semibittium) tumidum] O27
    |--B. turritelliformis Angas 1877 H08
    |--B. vancouverense Dall & Bartsch 1910 [=B. (Semibittium) vancouverense ] O27
    |--B. varium (Pfeiffer 1840) [=Diastoma varium; incl. D. virginica Henderson & Bartsch 1914, Bittium virginicum] H77
    |--B. vitreum Suter 1908 F27 [=Zebittium vitreum P61]
    `--B. xanthum Watson 1886 H09

Bittium Leach in Gray 1847 [=Cerithiolum Tiberi 1869; incl. Bittiolum Cossmann 1906, Bittiscalia Finlay & Marwick 1937, Brachybittium Weisbord 1962, Cacozelia Iredale 1924 non Grote 1878, Cacozeliana Strand 1928, Dahlakia Biggs 1971, Eubittium Cotton 1937, Inobittium Monterosato 1917, Lirobittium Bartsch 1911, Monobittium Monterosato 1917, Parabittium Cotton 1932 non Cossmann 1902, Semibittium Cossmann 1869, Stylidium Dall in Bartsch 1907 nec Loureiro 1790 (ICBN) nec Swartz 1805 (ICBN), Zebittium Finlay 1927; Bittiidae, Bittiinae] H77

Bittium eschrichti (Middendorff 1849) H77 [=Turritella eschrichtii C64, B. (*Stylidium) eschrichti H77; incl. Cerithium filosum Gld. 1849 non Phil. 1848 C64, B. filosum C64]

*Bittium reticulatum (Costa 1778) H77 [=Strombiformis reticulatus H77, *Cerithiolum (Strombiformis) reticulatum H77, Cerithium reticulatum O27, Murex reticulatus H77]

*Type species of generic name indicated


[BD86] Barash, A., & Z. Danin. 1986. Further additions to the knowledge of Indo-Pacific Mollusca in the Mediterranean Sea (Lessepsian migrants). Spixiana 9 (2): 117–141.

[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.

[D56] Dawes, B. 1956. The Trematoda with special reference to British and other European forms. University Press: Cambridge.

[F27] Finlay, H. J. 1927. A further commentary on New Zealand molluscan systematics. Transactions and Proceedings of the New Zealand Institute 57: 320–485.

[H08] Hedley, C. 1908. Studies on Australian Mollusca. Part X. Proceedings of the Linnean Society of New South Wales 33: 456–489, pls 7–10.

[H09] Hedley, C. 1909. The Marine Fauna of Queensland: Address by the President of Section D. Australasian Association for the Advancement of Science: Brisbane.

[H77] Houbrick, R. S. 1977. Reevaluation and new description of the genus Bittium (Cerithiidae). Veliger 20 (2): 101–106.

[M54] Macpherson, J. H. 1954. Molluscs (sea shells and snails). In: Willis, J. M. (ed.) The Archipelago of the Recherche pp. 55–63. Australian Geographical Society: Melbourne.

[M01] Melville, J. C. 1901. A few further remarks upon the Erythrean molluscan fauna, with descriptions of seven species from Aden, in the collection of Commander E. R. Shopland, R.I.M. Annals and Magazine of Natural History, series 7, 7: 550–556.

[O27] Oldroyd, I. S. 1927. The Marine Shells of the West Coast of North America vol. 2 pt 3. Stanford University Press: Stanford University (California).

[P79] Petterd, W. F. 1879. List of the freshwater shells of Tasmania. Journal of Conchology 2: 80–88.

[P61] Powell, A. W. B. 1961. Shells of New Zealand: An illustrated handbook 4th ed. Whitcombe and Tombs Limited: Christchurch.

[WG71] Wilson, B. R., & K. Gillett. 1971. Australian Shells: illustrating and describing 600 species of marine gastropods found in Australian waters. A. H. & A. W. Reed: Sydney.

Last updated: 11 September 2021.

No comments:

Post a Comment

Markup Key:
- <b>bold</b> = bold
- <i>italic</i> = italic
- <a href="">FoS</a> = FoS