''Penion'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of large marine

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ...

s, commonly known as siphon whelks, classified within the mollusc

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Austrosiphonidae The Austrosiphonidae are a taxonomic family of large sea snails, often known as whelks.MolluscaBase eds. (2021). MolluscaBase. Austrosiphonidae Cotton & Godfrey, 1938. Accessed through: World Register of Marine Species at: http://www.marinespec ...

, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=488452 on 2021-12-24

Description

Siphon whelks are large, benthic marine

s, or

whelks Whelk (also known as scungilli) is a common name applied to various kinds of sea snail. Although a number of whelks are relatively large and are in the family Buccinidae (the true whelks), the word ''whelk'' is also applied to some other marin ...

. Powell A. W. B., ''New Zealand Mollusca'', William Collins Publishers Ltd, Auckland, New Zealand 1979 Willan, R.C., de C. Cook, S., Spencer, H.G., Creese, R.G., O’Shea, S., Jackson, G.D. Phylum Mollusca. In: de C. Cook, S.C. (eds.), ''New Zealand Coastal Marine Invertebrates 1'', 406 – 407. Canterbury University Press, Christchurch, New Zealand ''Penion'' are commonly called siphon whelks because they have a very long

siphon A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...

. Species typically have a large, pointed operculum. Ponder, W.F. 1973. A review of the Australian species of ''Penion'' Fischer (Neogastropoda: Buccinidae). Journal of the Malacological Society of Australia 2: 401–428.

Radula The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...

e have 3 or 4 cusps on lateral teeth and 3 cusps on central teeth. Males have a long, dorso-ventrally flattened penis, and correspondingly females have a large pallial oviduct and albumen gland. However, geometric morphometric investigation of '' P. chathamensis'' indicates that secondary sexual dimorphism is not prominent for shell shape or size. Shells of ''Penion'' vary significantly in shape, size and colouration, making the distinction of species difficult. Shells are fusiform with a tall spire of roughly equal height to the aperture and siphonal canal combined.

Protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also calle ...

morphology is also highly variable, from 1.5 - 4.0 whorls in height. The siphonal canal of the shell is often long to protect the elongated siphon. Small shells (or fossils) can be confused with those of ''

Aeneator An ''aeneator'' ( lat, aēneātor or ) was a specialized player of wind instruments who was attached to a Roman military unit. The word comes from Latin ''aēneus'' or ''ahēneus'', "brazen", from ''aes'', "copper alloy". While the size of individ ...

'' or ''

Antarctoneptunea ''Antarctoneptunea'' is a genus of sea snails, marine gastropod mollusks in the family Austrosiphonidae, the true whelks. Distribution ''Antarctoneptunea'' marine snails occur in deep water surrounding New Zealand and in Southern Ocean encir ...

''. Shell size can vary quite significantly among populations of ''Penion''. A species, ''Penion fairfieldae'' was formerly recognised, but recent genetic data has demonstrated that the species is indistinguishable from '' Penion chathamensis''. Shells originally recognised as ''P. fairfieldae'' can be distinguished from ''P. chathamensis'' using shell size, but not using shell shape.

Ecology

Most species occur in deep water, and inhabit soft sediments on the continental shelf. Dell, R.K. 1962. New Zealand Marine Provinces - do they exist? Tuatara, 10: 43 - 52
Online Copy courtesy of New Zealand Electronic Text Collection
/ref> All species of ''Penion'' have a wide ranging diet, and are

detritivores Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

and carnivores that actively hunt prey. '' P. sulcatus'' is known to feed on mussels and '' Dosina zelandica zelandica''.Wilson, B. 1994. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, WA : Odyssey Publishing Vol. 2 370 pp. Members of the genus have similar niche placement to species of '' Buccinum'' in the Northern Hemisphere.

Distribution

''Penion'' species are restricted to the Southern Hemisphere. Two extant species are currently classified in waters surrounding Australia and five extant species are documented from

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

. Numerous fossil species are recorded in New Zealand, Australia,

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

and

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

, and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest co ...

.Stilwell, J.D., Zinsmeister, W.J. 1992. Molluscan systematics and biostratigraphy, lower Tertiary La Meseta Formation, Seymour Island, Antarctic Peninsula. American Geophysical Union Antarctica Research Series 55: 126-128. DOI: 10.1029/AR055
In New Zealand, many fossils are found in

Wanganui Basin The Wanganui Basin (also spelled Whanganui Basin) is an onshore-offshore basin on the North Island of New Zealand. The basin provides an important stratigraphic and palaeontological record for the late Neogene marine environment of New Zealand. L ...

sediments. During the voyage of HMS ''Beagle'', fossils of ''

P. subrectus P. is an abbreviation or acronym that may refer to: * Page (paper), where the abbreviation comes from Latin ''pagina'' * Paris Herbarium, at the ''Muséum national d'histoire naturelle'' * ''Pani'' (Polish), translating as Mrs. * The ''Pacific Rep ...

'' were among palaeontological samples collected by

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all speci ...

from the mouth of the Santa Cruz River in Argentina.

Evolution

''Penion'' is currently classified within

Buccinidae The Buccinidae are a very large and diverse taxonomic family of large sea snails, often known as whelks or true whelks.Bouchet, P.; Gofas, S. (2010). Buccinidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. A ...

, the family of true whelks. Alternatively they have been referred to the family of

Buccinulidae The Buccinidae are a very large and diverse taxonomic family of large sea snails, often known as whelks or true whelks.Bouchet, P.; Gofas, S. (2010). Buccinidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. A ...

.

Molecular phylogenetic trees based on mitochondrial genomic and nuclear

ribosomal DNA Ribosomal DNA (rDNA) is a DNA sequence that codes for ribosomal RNA. These sequences regulate transcription initiation and amplification, and contain both transcribed and non-transcribed spacer segments. In the human genome there are 5 chrom ...

sequence data indicate that ''Penion'' is closely related to two genera: ''

Kelletia ''Kelletia'' is a genus of large sea snails, whelks, a marine gastropod molluscs in the family Austrosiphonidae, the true whelks.Bouchet, P.; Fraussen, K. (2015). Kelletia Bayle in P. Fischer, 1884. In: MolluscaBase (2015). Accessed through ...

'' found in the north Pacific Ocean and ''

'', distributed in waters surrounding New Zealand and Antarctica. Radulae and opercula morphology is similar between ''Penion'' and ''Kelletia''. It is possible that the earliest known fossils of ''Penion'' belonging to '' P. proavitus'' from the New Zealand

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...

( Teurian), actually represent a stem lineage that was the common ancestor of these three genera. In Australian waters, the

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

'' P. mandarinus'' and '' P. maximus'' have overlapping geographic ranges (

sympatry In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species s ...

), and may have evolved from a

common ancestor Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal comm ...

via

niche differentiation In ecology, niche differentiation (also known as niche segregation, niche separation and niche partitioning) refers to the process by which competing species use the environment differently in a way that helps them to coexist. The competitive exclu ...

based on prey size and water depth. In New Zealand, the extinct species '' Penion exoptatus'', '' Penion clifdenensis'', and potentially also '' Penion marwicki'', may belong to the same evolutionary lineage as the extant species '' Penion sulcatus''. This hypothesis is based on geometric morphometric analysis of shell shape and size for all four taxa, as well as the analysis of morphometric variation exhibited all living species of ''Penion''.

Human use

''Penion'' shells are prized by shell collectors. Shells found in middens of historic

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the Co ...

settlements indicate that '' P. sulcatus'' may have been intentionally foraged as a food-source.

Species

Species and subspecies in the genus ''Penion'' include: *

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species). It is one of the modern descendan ...

Penion affixus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' ( Finlay, 1930) * † ''

Penion antarctocarinatus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' (Stilwell & Zinsmeister, 1992) *

Penion asper ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' ( Marwick, 1928) *

Penion australocapax ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' Stilwell & Zinsmeister, 1992 *

Penion bartrumi ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' (Laws, 1941) *

Penion brazieri ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' ( Fleming, 1955) * '' Penion chathamensis'' ( Powell, 1938) *

'' Penion clifdenensis'' ( Finlay, 1930) *

Penion crassus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' Frassinetti, 2000 *

'' Penion crawfordi'' ( Hutton, 1873) * ''

Penion cuvierianus ''Penion cuvierianus'' is a species of very large predatory sea snail or whelk, commonly called the flaring penion, a marine gastropod mollusc in the family Buccinidae, the true whelks. Description ''Penion cuvierianus'' is a very large spe ...

'' ( Powell, 1927) Ponder, W.F. 1975. Identity of ''Penion dilatatus'' (Quoy & Gaimard, 1833) (Mollusca: Buccinidae). New Zealand Journal of Marine and Freshwater Research 9 (4): 569-571.. *

'' Penion darwinianus'' (Philippi, 1887) *

Penion diversus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' Frassinetti, 2000 *

'' Penion domeykoanus'' (Philippi, 1887) *

'' Penion exoptatus'' ( Powell & Bartrum, 1929) *

Penion finlayi ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' (Laws, 1930) *

Penion gauli ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' ( Marwick, 1928) *

Penion haweraensis ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' ( Powell, 1931) *

Penion hiatulus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Registe ...

'' ( Powell, 1947) *

Penion huttoni ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Registe ...

'' (L.R. King, 1934) *

Penion imperfectus ''Penion'' is a genus of large marine (ocean), marine snails, commonly known as siphon whelks, classified within the mollusc family (biology), family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 188 ...

'' ( Powell, 1947) *

Penion interjunctus ''Penion'' is a genus of large marine (ocean), marine snails, commonly known as siphon whelks, classified within the mollusc family (biology), family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 188 ...

'' ( Finlay, 1930) *

Penion koruahinensis ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Registe ...

'' ( Powell & Bartrum, 1928) * ''

Penion lineatus ''Penion lineatus'' is a species of medium-sized marine (ocean), marine snail or whelk, belonging to the true whelk family (biology), family Buccinidae. It was described in 2018. Description Adult shells are between 68 mm and 172 mm in ...

Marshall Marshall may refer to: Places Australia * Marshall, Victoria, a suburb of Geelong, Victoria Canada * Marshall, Saskatchewan * The Marshall, a mountain in British Columbia Liberia * Marshall, Liberia Marshall Islands * Marshall Islands, an ...

, Hills & Vaux, 2018 *

'' Penion longirostris'' (Tate, 1888) *

Penion macsporrani ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' (Philippi, 1887) * '' Penion mandarinus'' (Duclos, P.L., 1831) *

'' Penion marwicki'' ( Finlay, 1930) * '' Penion maximus'' ( Tryon, G.W., 1881) *

'' Penion oncodes'' (Philippi, 1887) * '' Penion ormesi'' ( Powell, 1927) *

Penion parans ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Registe ...

'' ( Finlay, 1930) *

Penion patagonensis ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' Reichler, 2010 *

Penion petitianus ''Penion'' is a genus of large marine (ocean), marine snails, commonly known as siphon whelks, classified within the mollusc family (biology), family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 188 ...

'' (d'Orbigny, 1842) *

Penion proavitus ''Penion proavitus'' is an extinct species of marine snail or whelk, belonging to the true whelk family Buccinidae. Description ''Penion proavitus'' fossils are the earliest known specimens of ''Penion'' siphon whelks. The species was medium ...

'' ( Finlay & Marwick, 1937) *

Penion roblini ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' (Tenison Woods, 1876) *

Penion spatiosus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' (Tate, 1888) *

'' Penion subrectus'' (Ihering, 1899) *

Penion subreflexus ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Registe ...

'' (G.B. Sowerby I, 1846) *

Penion subregularis ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Registe ...

'' (d'Orbigny, 1852) * '' Penion sulcatus'' (

Lamarck Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), often known simply as Lamarck (; ), was a French naturalist, biologist, academic, and soldier. He was an early proponent of the idea that biolog ...

, 1816) *

Penion winthropi ''Penion'' is a genus of large marine snails, commonly known as siphon whelks, classified within the mollusc family Austrosiphonidae, the true whelks.MolluscaBase eds. (2021). MolluscaBase. Penion P. Fischer, 1884. Accessed through: World Regi ...

'' ( Marwick, 1965)

''Nomina dubia''

Beu 2009 lists the following Antarctic fossil species as

nomina dubia In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

: *

''Penion gazdzicki'' (Karczewski, 1987), previously '' Neptunea'' and '' Beringius'', potentially ''

Species brought into synonymy

* ''Penion adustus'' (Philippi, 1845): synonym of '' Penion sulcatus'' (Lamarck, 1816) * ''Penion cuvierianus jeakingsi'' ( Powell, 1947): synonym of '' Penion ormesi'' ( Powell, 1927) * ''Penion dilatatus'' (Quoy & Gaimard, 1833): synonym of '' Penion sulcatus'' (Lamarck, 1816) * ''Penion fairfieldae'' ( Powell, 1947): synonym of '' Penion chathamensis'' ( Powell, 1938)

Reclassified species

* ''Penion benthicolus'' Dell, 1956: accepted as '' Antarctoneptunea benthicola'' (Dell, 1956)

References

External links

Museum of New Zealand Te Papa Tongarewa, Taxon: ''Penion'' (Genus)

Auckland War Memorial Museum: ''Penion'' specimens

* ttp://www.molluscs.otago.ac.nz/ Checklist of the Recent Mollusca Recorded from the New Zealand Exclusive Economic Zone
Molluscs of Tasmania: Buccinidae - Siphonaliinae: Genus ''Penion'' Fischer, 1884 - “whelks”