Homalopoma sanguineum, copyright H. Zell.

Belongs within: Vetigastropoda.

The Colloniinae are a group of small gastropods characterised by a periumbilical cord (Monari et al. 1996).

What we have here is a failure to communicate
Published 19 October 2021

To those without much of a background in taxonomy, the various rules governing the naming of organisms can seen frustratingly byzantine and laborious. “Surely,” they think to themselves as they despairingly attempt to come to grips with concepts of holotypes and lectotypes, synonyms and homonyms, “there must be an easier way of doing this”. Nevertheless, the easiest way to develop an appreciation for just how valuable it is to have a set of rules governing nomenclature is to attempt to deal with anything dating back to the days before such rules were established. Settle back, readers, while I tell you a tale. Pour yourself a drink. You’re going to hate this.

Collonista glareola, a species that just might be related to the subject of this post, copyright Huang, Fu & Poppe.

These days, it is generally accepted that before a new name can enter general use, it should be clearly established in some form of formal, widely-accessible publication just to what it is that the name is supposed to refer. Back in the day, however, this was not always the case. A century or two ago, the communities of researchers working on a particular group of organisms were often small, and it was not uncommon for names to effectively spread through personal correspondence or word of mouth alone. One naturalist might refer to a new genus he had come to recognise in a letter to another, and the latter naturalist may then assign his own species to that genus without the first naturalist ever publishing a formal description. At the time, this might not be seen as much of an issue: after all, if there was ever any question as to the first naturalist’s original intent, surely it could be clarified by simply writing to him personally?

The name Leptothyra seems to have been established in this kind of way in the mid-1800s by the American naturalist James Graham Cooper for a genus of small marine gastropods (belonging to the vetigastropods, related to the top shells and cat’s-eyes) found on the coast of California. In 1871, W. H. Dall attributed the name to an unpublished manuscript of Cooper’s and cited the type species as Linnaeus’ Turbo sanguineus, a Mediterranean species to which Cooper had also attributed specimens from the Pacific. As it happens, Turbo sanguineus was already the type species for an earlier genus name, Homalopoma, so Dall’s ‘Leptothyra‘ would be considered invalid and give precedence to Homalopoma. However, in 1869 the name Leptothyra had been used by W. H. Pease for L. costata, a species from Hawaii, without direct reference to any other species (thus making L. costata the effective type species of Leptothyra). Subsequent authors often considered ‘Leptothyra Pease’ to be a separate genus from Homalopoma/’Leptothyra Dall’. At least one author who did not, Henry A. Pilsbry (1888), nevertheless used the name Leptothyra under the mistaken belief that the name Homalopoma was preoccupied. Over time, numerous species both living and fossil from around the Pacific were assigned to Leptothyra in one way or another.

It was not until over a century later that Coan (1986) pointed out that the name Leptothyra had appeared in print even earlier than Pease’s usage. Cooper himself had used the name in a list of Californian molluscs in 1867. Even though Cooper’s list lacked any descriptive details, this counts as enough to validate the name because he included species for which descriptions had already been published under other genera. One of these was Turbo sanguineus, which Coan officially designated as type species and fixed Leptothyra‘s status as an invalid later name for Homalopoma.

Which leaves open the question of what one should call the genus formerly known as ‘Leptothyra Pease’. It doesn’t help matters that Pease’s ‘Leptothyra costata‘ has apparently never been illustrated and its identity has been open to question. Iredale (1918) proposed the name Collonista for use with species previously included in Leptothyra, stating that the latter “proves to have been first published by Pease in connexion with a juvenile shell of a different genus”, but gave no further elaboration or explanation how he reached that conclusion. The online resource WoRMS lists L. costata as a junior synonym of the widespread Pacific species Collonista verruca, but I have been unable to find where that synonymy was published. Nevertheless, any sort of replacement name for ‘Leptothyra Pease’ seems like it would be misguided at best. It is unlikely that L. costata represents any genus otherwise unknown and, even without any explicit statement to the effect, it is quite possible that Pease only intended to assign his species to Cooper’s manuscript genus rather than establish a new genus of his own. Any concept of a genus Leptothyra is best left to sink into the annals of history.

Systematics of Colloniinae

Characters (from Monari et al. 1996): Phaneromphalous base with periumbilical cord, carina or ridge formed by small enlarged part of otherwise simple or slightly thickened peristome. Angulation on protoconch whorl and/or opisthocline lineation on teleoconch rarely appear. Operculum (where known) calcareous.

<==Colloniinae [Colloniini, Homalopomatinae, Homalopomatini]BR05
    |--Bakonyia Szabó 1981MCS96
    |--Coanollonia Woodring 1928KC60
    |    `--*C. ambla Woodring 1928KC60
    |--Cyniscella Cossmann 1888KC60
    |    `--*C. cornupastoris (Lamarck 1804) [=Cyclostoma cornupastoris]KC60
    |--Gelasinostoma Gardner 1947KC60
    |    `--*G. elegantulum (Dall 1892) [=Collonia elegantula]KC60
    |--Otomphalus Cossmann 1902KC60
    |    `--*O. dumasi Cossmann 1902KC60
    |--Anadema Adams & Adams 1854KC60
    |    `--*A. caelata (Adams 1854) [=Omphalius caelata]KC60
    |--Leptocollonia Powell 1951 [incl. Cynisca Adams & Adams 1854 non Gray 1844]KC60
    |    `--*L. thielei Powell 1951KC60
    |--Rangimata Marwick 1928KC60
    |    `--*R. pervia Marwick 1928KC60
    |--Tipua Marwick 1943KC60
    |    `--*T. tricincta (Marshall 1919) [=Submargarita tricincta]KC60
    |--Vexinia Cossmann 1918KC60
    |    `--*V. crassa (Baudon 1853) [=Delphinula crassa]KC60
    |--Otollonia Woodring 1928KC60
    |    |--*O. siderea (Guppy 1896) [=Liotia siderea]KC60
    |    `--O. fricki (Crosse 1865) [=Arene (Otollonia) fricki]PP78
    |--‘Bothropoma’ Thiele 1924 non Wagner 1908 [Bothropomatinae]BR05
    |    |--*B. isseli Thiele 1924BR17
    |    `--B. rubrostriatum Rolán, Rubio & Fernández-Garcés 1997BC01
    |--Cantrainea Jeffreys 1883 [=Cantraineia Fischer 1885]KC60
    |    |--*C. peloritanum (Cantraine 1835) [=Turbo peloritanus, Homalopoma (*Cantrainea) peloritanum]KC60
    |    `--C. panamense (Dall 1908)H84
    |--Cirsochilus Cossmann 1888KC60
    |    |--*C. (Cirsochilus) striatum (Lamarck 1804) [=Delphinula striata]KC60
    |    `--C. (Claibornia Palmer 1937)KC60
    |         `--C. (*C.) lineatum (Lea 1933) [=Turbo lineata]KC60
    |--Argalista Iredale 1915KC60
    |    |--*A. fluctuata (Hutton 1883)P61 (see below for synonymy)
    |    |--A. corallina (Cotton & Godfrey 1935)W93
    |    |--A. crassicostata (Murdoch 1905)P61
    |    |--A. fugitiva (Hedley 1911)W93
    |    |--A. micans Powell 1931P61
    |    |--A. nana Finlay 1930P61
    |    |--A. rosea (Tenison Woods 1876)W93
    |    |--A. roseopunctata (Angas 1880)W93
    |    |--A. rotella Powell 1937P61
    |    |--A. umbilicata Powell 1926P61
    |    `--A. variecostata Powell 1937P61
    |--Collonia Gray 1850BR05
    |    |  i. s.: C. candida Pease 1861 [=C. candidus, Leptothyra candida]K65
    |    |         C. variabilis Pease 1861 [=Phasianella variabilis]K65
    |    |--*C. (Collonia) marginata (Lamarck 1804)KC60 [=Delphinula marginataKC60, Turbo marginatusC64]
    |    |--C. (Bonnetella Cossmann 1908) [incl. Bonnetia Cossmann 1907 non Robineau-Desvoidy 1830]KC60
    |    |    `--C. (*B.) planispira (Cossmann 1907) [=Bonnetia planispira]KC60
    |    |--C. (Circulopsis Cossmann 1902)KC60
    |    |    `--C. (*C.) megalomphalus Cossmann 1902KC60
    |    |--C. (Heniastoma Cossmann 1918)KC60
    |    |    `--C. (*H.) flammulata Cossmann 1888KC60
    |    `--C. (Parvirota Cossmann 1902)KC60
    |         `--C. (*P.) rotatoria (Deshayes 1863) [=Turbo rotatorius]KC60
    |--Collonista Iredale 1918 [=Leptothyra Pease 1869 non Cooper 1867]W93
    |    |--C. verruca (Gould 1845)W93 [incl. *Leptothyra costata Pease 1869KC60, *C. costataW93]
    |    |--‘Leptothyra’ bacula Carpenter 1864O27
    |    |--‘Leptothyra’ carpenteri Pilsbry 1888O27
    |    |--‘Leptothyra’ grippi Dall 1911O27
    |    |--‘Leptothyra’ juanensis Dall 1919O27
    |    |--C. laeta (Montrouzier 1863)W93 [=Turbo laetusH09, Leptothyra laetaH09]
    |    |--‘Leptothyra’ lurida Dall 1885O27
    |    |--‘Leptothyra’ morini Viader 1951L96
    |    |--C. nanina (Sowerby 1864)W93 [=Turbo naninusH09, Leptothyra naninaH09]
    |    |--‘Leptothyra’ paucicostata Dall 1871O27
    |    |    |--L. p. paucicostataO27
    |    |    `--L. p. fenestrata Bartsch 1919O27
    |    `--C. picta (Pease 1868)F27, KC60 [=Collonia pictaKC60, Homalopoma (Collonista) pictumKC60]
    `--Homalopoma Carpenter 1864BR05 [incl. Leptonyx Carpenter 1864 non Swainson 1833KC60]
         |  i. s.: ‘Leptonyx’ bacula Carpenter 1864C64
         |         H. carpenteri (Pilsbry 1888)H84
         |         H. eurystoma (White 1885)KBP02
         |         H. chica Kiel, Bandel & Perrilliat 2002KBP02
         |         H. minuta (Quintero & Revilla 1966)KBP02
         |--*H. (Homalopoma) sanguineum (Linnaeus 1758)KC60 (see below for synonymy)
         |--H. (Boutillieria Cossmann 1888) [incl. Otaulax Cossmann 1888]KC60
         |    `--H. (*B.) eugeni (Deshayes 1863) [=Turbo eugeni]KC60
         |--H. (Eutinochilus Cossmann 1918) [=Homalochilus Cossmann 1892 non Fischer 1856]KC60
         |    `--H. (*E.) miliaris (Cossmann 1892) [=Collonia miliaris]KC60
         |--H. (Leptothyropsis Woodring 1928)KC60
         |    `--H. (*L.) philipianum (Dall 1889) [=Leptothyra philipiana]KC60
         `--H. (Phanerolepida Dall 1907)KC60
              `--H. (*P.) transenna (Watson 1879) [=Turbo transenna]KC60

*Argalista fluctuata (Hutton 1883)P61 [=Cyclostrema fluctuatumP61, Homalopoma (*Argalista) fluctuatumKC60; incl. Argalista fluctuata var. immaculata (Suter 1908)F27]

*Homalopoma (Homalopoma) sanguineum (Linnaeus 1758)KC60 [=Turbo sanguineusKC60, Leptonyx sanguineusC64; incl. T. coccineusC64]

*Type species of generic name indicated


[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.

[BC01] Boyko, C. B., & J. R. Cordeiro. 2001. Catalog of Recent type specimens in the Division of Invertebrate Zoology, American Museum of Natural History. V. Mollusca, part 2 (class Gastropoda [exclusive of Opisthobranchia and Pulmonata], with supplements to Gastropoda [Opisthobranchia], and Bivalvia). Bulletin of the American Museum of Natural History 262: 1–170.

[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.

Coan, E. 1986. Some additional taxonomic unites that first appear in publications by J. G. Cooper. Nautilus 100 (1): 30–32.

Cooper, J. G. 1867. Geographical catalogue of the Mollusca found west of the Rocky Mountains, between latitudes 33° and 49° north. Geological Survey of California: San Francisco.

Dall, W. H. 1871. Descriptions of sixty new forms of mollusks from the west coast of North America and the North Pacific Ocean, with notes on others already described. American Journal of Conchology 7 (2): 93–160, pls 13–16.

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

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

[H84] Hickman, C. S. 1984. Implications of radular tooth-row functional integration for archaeogastropod systematics. Malacologia 25 (1): 143–160.

Iredale, T. 1918. Molluscan nomenclatural problems and solutions.—No. 1. Proceedings of the Malacological Society of London 13 (1–2): 28–40.

[K65] Kay, E. A. 1965. Marine molluscs in the Cuming collection, British Museum (Natural History) described by William Harper Pease. Bulletin of the British Museum (Natural History): Zoology Supplement 1: 1–96, 14 pls.

[KBP02] Kiel, S., K. Bandel & M. del C. Perrilliat. 2002. New gastropods from the Maastrichtian of the Mexcala Formation in Guerrero, southern Mexico, part II: Archaeogastropoda, Neritimorpha and Heterostropha. Neues Jahrbuch für Geologie und Paläontologie—Abhandlungen 226 (3): 319–342.

[KC60] Knight, J. B., L. R. Cox, A. M. Keen, R. L. Batten, E. L. Yochelson & R. Robertson. 1960. Gastropoda: systematic descriptions. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt I. Mollusca 1: Mollusca—General Features, Scaphopoda, Amphineura, Monoplacophora, Gastropoda—General Features, Archaeogastropoda and some (mainly Paleozoic) Caenogastropoda and Opisthobranchia pp. I169–I331. Geological Society of America, and University of Kansas Press.

[L96] Loch, I. 1996. Notice: R. Viader collection. Molluscan Research 17: 110.

[MCS96] Monari, S., M. A. Conti & J. Szabó. 1996. Evolutionary systematics of Jurassic Trochoidea: the family Colloniidae and the subfamily Proconulidae. In: Taylor, J. D. (ed.) Origin and Evolutionary Radiation of the Mollusca pp. 199–204. Oxford University Press: Oxford.

[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).

Pease, W. H. 1869. Descriptions of new species of marine Gasteropodae inhabiting Polynesia. American Journal of Conchology 5 (2): 64–79.

[PP78] Poorman, F. L., & L. H. Poorman. 1978. Additional molluscan records from Bahía de Los Angeles, Baja California Norte. Veliger 20 (4): 369–374.

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

[W93] Wilson, B. 1993. Australian Marine Shells vol. 1. Prosobranch Gastropods. Part One. Odyssey Publishing: Kallaroo (Western Australia).

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