Colus islandicus, copyright Femorale.

Belongs within: Buccinoidea.

The Colini are a group of whelks including species bearing a leaf-shaped operculum with a terminal or subspiral nucleus. Members include the boreal genus Neptunea, characterised by a large, fusiform shell with strongly convex whorls and a rather short, slightly twisted siphonal canal.

Colus and Co.
Published 9 February 2022

The neogastropods have long been a challenge taxonomically. They are extremely diverse, encompassing a large number of species with a wide range of lifestyles, but they also exhibit exhibit regular patterns of convergence and/or conservatism between different lineages. Perhaps the most challenging group of all has been the whelks, commonly recognised as the superfamily Buccinoidea, a massive radiation of over 3300 known species. Whelks are particularly diverse in colder regions of the world’s oceans, including amongst their number there the members of the family Colidae.

Hairy colus Colus pubescens, copyright E. A. Lazo-Wasem.

Colus has been used as the basis of a family group name at many levels of whelk classification, whether it be Colidae, Colinae or Colini. The gastropod classification laid out by Bouchet et al. (2017) recognised ‘Colini’ as a diverse tribe within the main whelk family Buccinidae, including a range of cold-water taxa. However, a more recent phylogenetic analysis of the buccinoids by Kantor et al. (2022) found Bouchet et al.‘s concept of Colini to be polyphyletic, placing the type genus Colus outside what the called the ‘core Buccinoidea’. As such, they raised Colidae to the status of a separate family and restricted it to just two genera, Colus and Turrisipho.

In this restricted form, the Colidae are thin-shelled, medium-sized to large whelks with the largest having shells up to twenty centimetres in length. The shells are fusiform to ovate in shape with a more or less elongate siphonal canal and covered by a brown periostracum. Axial sculpture is absent; spiral sculpture is expressed as more or less prominent cords. The aperture is closed with a operculum bearing a terminal nucleus. The animal has a more or less long proboscis. The radula bears three teeth per row; the middle tooth has a more or less square base and one to three cusps, with the middle cusp the largest, whereas the lateral teeth bear three hooked cusps with the outermost cusp significantly larger than the other two. None of these features, it should be noted, is entirely unique to the Colidae (Kantor et al. 2022).

Turrisipho dalli, from BoldSystems.

Members of the Colidae are found in the Arctic and northern Atlantic Oceans, from subtidal to bathyal depths. Because they are not targeted commercially, the life habits of colids have not been well studied. However, what we do know indicates that they are likely predators on other invertebrates (Kosyan 2007). The long proboscis of most species is probably used to pull infaunal animals such as amphipods and bivalves out of their burrows. Colids have well-developed salivary glands and it is possible that these may produce toxins as found in other neogastropods. They do not have anything like the elaborate venom delivery setups like those found in the conoids, but even a little dose of toxic saliva helps to subdue a struggling crustacean.

Systematics of Colidae
<==Colidae [Chrysodomidae, Chrysodominae, Colinae, Colini, Colusina]
    |--Pomahakia Finlay 1927F27b
    |    `--*P. aberrans Finlay 1927 [=Fusus plicatilis Hutton 1873 non Wood 1848]F27b
    |--Searlesia Harmer 1914O27, AV03
    |    `--*S. costiferum (Wood 1848) [=Trophon costiferum]AV03
    |--Turrisipho Dautzenberg & Fischer 1912KF22
    |    |--*T. lachesis (Mörch 1869) [=Fusus lachesis]KF22
    |    |--T. moebii (Dunker & Metzger 1875)KF22
    |    `--T. voeringii Bouchet & Warén 1985KF22
    `--Colus Röding 1798BR05
         |  i. s.: C. arctatus Conrad 1855C64
         |         C. bensoniA27
         |         C. bukini Kantor 1984KF22
         |         C. delicatulus [=Verconella delicatula]F27a
         |         C. kaunhoweni Finlay 1927 [=Fusus bicinctus Kaunhowen 1898 non Hutton 1873]F27b
         |         C. minor (Dall 1925)KF22
         |         C. solidusA27
         |         C. stimpsoni (Mörch 1867)W78
         |         ‘Columbarium’ suteri Smith 1915F27a
         |         C. teschi Finlay 1927 [=Latirus fusiformis Tesch 1915 non Hoernes & Auinger 1891]F27b
         |         C. (Anomalosipho Dautzenberg & Fischer 1912)O27
         |           |--C. (A.) conulus Aurivillius 1885O27
         |           `--C. (A.) martensi Krause 1885O27
         |         C. (Limatofusus Dall 1918)O27
         |           |--C. (L.) dimidiatus Dall 1919O27
         |           |--C. (L.) halimeris Dall 1919O27
         |           |--C. (L.) morditus Dall 1919O27
         |           |--C. (L.) pulcius Dall 1919O27
         |           |--C. (L.) severinus Dall 1919O27
         |           |--C. (L.) tahwitanus Dall 1918O27
         |           |--C. (L.) timetus Dall 1919O27
         |           |--C. (L.) trombinus Dall 1919O27
         |           `--C. (L.) trophius Dall 1919O27
         |--*C. (Colus) islandicus (Mohr 1786)BR17, KF22, BR17 (see below for synonymy)
         `--+--C. sabinii (Gray 1824)KF22
            `--+--C. holboelli (Møller 1842)KF22
               `--+--C. gracilis (da Costa 1778)KF22
                  `--C. turigulus (Friele 1877)KF22
Nomen nudum: Colus modestusA27

*Colus (Colus) islandicus (Mohr 1786)BR17, KF22, BR17 [=Murex islandicusBR17, Chrysodomus islandicusKF22, Neptunea icelandicaC64]

*Type species of generic name indicated


[A27] Allan, R. S. 1927. The geology and palaeontology of the Lower Waihao Basin, south Canterbury, New Zealand. Transactions and Proceedings of the New Zealand Institute 57: 265–309.

[AV03] Amano, K., & G. J. Vermeij. 2003. Evolutionary adaptation and geographic spread of the Cenozoic buccinid genus Lirabuccinum in the North Pacific. Journal of Paleontology 77 (5): 863–872.

[BR05] Bouchet, P., & J.-P. Rocroi. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1–2): 1–397.

[BR17] Bouchet, P., J.-P. Rocroi, B. Hausdorf, A. Kaim, Y. Kano, A. Nützel, P. Parkhaev, M. Schrödl & E. E. Strong. 2017. Revised classification, nomenclator and typification of gastropod and monoplacophoran families. Malacologia 61 (1–2): 1–526.

[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.

[F27a] Finlay, H. J. 1927a. A further commentary on New Zealand molluscan systematics. Transactions and Proceedings of the New Zealand Institute 57: 320–485.

[F27b] Finlay, H. J. 1927b. New specific names for austral Mollusca. Transactions and Proceedings of the New Zealand Institute 57: 488–533.

[KF22] Kantor, Y. I., A. E. Fedosov, A. R. Kosyan, N. Puillandre, P. A. Sorokin, Y. Kano, R. Clark & P. Bouchet. 2022. Molecular phylogeny and revised classification of the Buccinoidea (Neogastropoda). Zoological Journal of the Linnean Society 194 (3): 789–857.

Kosyan, A. R. 2007. Morphological features, ecology, and distribution of poorly studied molluscan genera of the Colinae subfamily (Gastropoda, Buccinidae) from the far eastern seas of Russia. Oceanology 47 (4): 531–536.

[O27] Oldroyd, I. S. 1927. The Marine Shells of the West Coast of North America vol. 2 pt 1. Stanford University Press: Stanford University (California).

[W78] West, D. L. 1978. Reproductive biology of Colus stimpsoni (Prosobranchia: Buccinidae). I. Male genital system. Veliger 20 (3): 266–273.

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