''Penion'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of large

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 Gastro ...

s, commonly known as siphon whelks, classified within the

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

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

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

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 mari ...

. 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 called ...

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 encirc ...

''. 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 ''Dosina mactracea'' is a species of marine bivalve mollusc in the family Veneridae The Veneridae or venerids, common name: Venus clams, are a very large family of minute to large, saltwater clams, marine bivalve molluscs. Over 500 living ...

''.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 ''Buccinum'' is a genus of medium-sized sea snails, marine gastropod molluscs in the family Buccinidae, the true whelks.Gofas, S.; Bouchet, P. (2014). Buccinum Linnaeus, 1758. Accessed through: World Register of Marine Species at http://www.marin ...

'' in the Northern Hemisphere.

Distribution

''Penion'' species are restricted to the Southern Hemisphere. Two extant species are currently classified in waters surrounding

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

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 smaller islands. It is the sixth-largest island count ...

. 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, th ...

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 east a ...

, 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 contine ...

.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 sediments. During the voyage of HMS ''Beagle'', fossils of '' P. subrectus'' were among palaeontological samples collected by

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

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.

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 chromos ...

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 (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

(

Teurian While also using the international geologic time scale, many nations–especially those with isolated and therefore non-standard prehistories–use their own systems of dividing geologic time into epochs and faunal stages. In New Zealand, these epo ...

), 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 t ...

'' 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 sh ...

), 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 excl ...

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 ''Penion sulcatus'' is a species of medium-to-large predatory marine snail or whelk, commonly called the northern siphon whelk or kākara nui in Māori, belonging to the true whelk family Buccinidae. Description ''Penion sulcatus'' is a medium- ...

''. 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 C ...

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

Species

Species and subspecies in the genus ''Penion'' include: * † '' Penion affixus'' (

Finlay Finlay is a masculine given name, and also a surname. The given name is represented in Scottish Gaelic as Fionnlagh. Given name Finlay *Finlay Mickel, Scottish skier *Finlay Currie (1878–1968), Scottish actor *Finlay Calder, Scottish rugby play ...

, 1930) * † '' Penion antarctocarinatus'' (Stilwell & Zinsmeister, 1992) * † '' Penion asper'' ( Marwick, 1928) * † '' Penion australocapax'' Stilwell & Zinsmeister, 1992 * † '' Penion bartrumi'' (Laws, 1941) * † '' Penion brazieri'' ( Fleming, 1955) * '' Penion chathamensis'' ( Powell, 1938) * † '' Penion clifdenensis'' (

, 1930) * † '' Penion crassus'' Frassinetti, 2000 * † '' Penion crawfordi'' ( Hutton, 1873) * '' Penion cuvierianus'' ( 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'' Frassinetti, 2000 * † '' Penion domeykoanus'' (Philippi, 1887) * † '' Penion exoptatus'' ( Powell & Bartrum, 1929) * † '' Penion finlayi'' (Laws, 1930) * † '' Penion gauli'' ( Marwick, 1928) * † '' Penion haweraensis'' ( Powell, 1931) * † '' Penion hiatulus'' ( Powell, 1947) * † '' Penion huttoni'' (L.R. King, 1934) * † '' Penion imperfectus'' ( Powell, 1947) * † '' Penion interjunctus'' (

, 1930) * † '' Penion koruahinensis'' ( Powell & Bartrum, 1928) * '' Penion lineatus''

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 i ...

, Hills & Vaux, 2018 * † '' Penion longirostris'' (Tate, 1888) * † '' Penion macsporrani'' (Philippi, 1887) * ''

Penion mandarinus ''Penion mandarinus'', common name the mandarin penion, southern siphon whelk or Waite's buccinum whelk, is a species of medium-to-large predatory sea snail or whelk, a marine gastropod mollusc in the family Buccinidae, the true whelks.Bouch ...

'' (Duclos, P.L., 1831) * † '' Penion marwicki'' (

, 1930) * ''

Penion maximus ''Penion maximus'' is a species of very large predatory sea snail or whelk, commonly known as giant whelk or great whelk, a marine gastropod mollusc in the family Buccinidae, the true whelks. Their shells are highly coveted due to the intric ...

'' ( Tryon, G.W., 1881) * † '' Penion oncodes'' (Philippi, 1887) * '' Penion ormesi'' ( Powell, 1927) * † '' Penion parans'' (

, 1930) * † '' Penion patagonensis'' Reichler, 2010 * † '' Penion petitianus'' (d'Orbigny, 1842) * † '' Penion proavitus'' (

& Marwick, 1937) * † '' Penion roblini'' (Tenison Woods, 1876) * † '' Penion spatiosus'' (Tate, 1888) * † '' Penion subrectus'' (Ihering, 1899) * † '' Penion subreflexus'' (G.B. Sowerby I, 1846) * † '' Penion subregularis'' (d'Orbigny, 1852) * ''

'' (

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'' ( Marwick, 1965)

''Nomina dubia''

Beu 2009 lists the following Antarctic fossil species as nomina dubia: * † ''Penion gazdzicki'' (Karczewski, 1987), previously ''Neptunea'' and ''Beringius'', potentially ''

Species brought into synonymy

* ''Penion adustus'' (Philippi, 1845): synonym of ''

'' (Lamarck, 1816) * ''Penion cuvierianus jeakingsi'' ( Powell, 1947): synonym of '' Penion ormesi'' ( Powell, 1927) * ''Penion dilatatus'' (Quoy & Gaimard, 1833): synonym of ''

'' (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

* [http://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”