''Mangelia hancocki'' is an extinct species of

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

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 ...

in the

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 ...

Mangeliidae Mangeliidae is a monophyletic family of small to medium-sized, predatory sea snails, marine gastropod mollusks in the superfamily Conoidea. Bouchet, P. (2011). Mangeliidae P. Fischer, 1883. In: MolluscaBase (2016). Accessed through: World Regis ...

. This fossil was discovered in the Galapagos Islands by

Leo George Hertlein Leo George Hertlein (1898 – 1972) was an American paleontologist and malacologist who studied the Recent and fossil mollusks of the eastern Pacific Ocean. Biography Hertlein was born on a farm in Pratt County, Kansas. After graduating hig ...

(1898–1972) and Archibald McClure Strong (1876 - 1951), who were there as a part of the Valero III's voyage to the tropical eastern Pacific. It was named for Captain G. Allan Hancock, the owner and captain of the Valero III. There are only two known collections of this species, both by

Description

''Full description from the original article.''

"Shell small, slender, with three and a half smooth nuclear whorls and five strongly sculptured normal whorls; axial sculpture of fourteen, low rounded, nearly vertical ribs; spiral sculpture of two, strong, rounded cords on the lower portion of the whorls which rise to elongated tubercles where they cross over the axial ribs; above these there are on the second whorl one, on the third whorl two, and the fourth whorl three, smaller spiral cords which ride over the axial ribs but with less ten- dency to form tubercles; the periphery of the last whorl marked by a sulcus about as wide as the space between the two major spiral cords; below this is a nodulous spiral cord similar to the two major spiral cords on the upper whorls; base and canal with six spiral cords similar to those on the upper portion of the whorls; outer lip thickened; with a small, rounded, unarmed anal sinus close to the suture, bounded on the inside of the outer lip by a strong denticle, immediately below which there are two smaller denticles; canal short, slightly recurved. The shell is white with irregularly disposed patches of brown, darker in the interspaces between the spiral cords. The type measures: length, 4.0 mm.; diameter, 1.5 mm."

Location of Discovery

''From original article''

Holotype, No. 4693 Calif. Acad. Sci. Paleo. Type Coll., from Loc. 27255 (C. A. S.), raised beach, 5 to 10 meters above sea level, at James Bay, James (San Salvador) Island, Galapagos Islands; L. G. Hertlein, collector. Pleistocene.

Distribution

This extinct marine species was found in

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

strata in the Galapagos Islands and in

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

strata of

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...

; age range: 5.332 to 0.012 Ma

Authors Notes

L. G. Hertlein and A. M. Strong left the following notes about this species.

In size, shape and general appearance this shell is quite similar to ''"Mangelia" (Steironepion) melanosticta'' Pilsbry and Lowe¹² but differs in the greater number of spiral cords and in the color pattern. The apparently smooth nuclear whorls are somewhat worn and in fresh specimens may show the spiral keel of Steironepion.
This species is named for Captain G. Allan Hancock, owner and captain of the exploration cruiser Velero III, through whose courtesy the senior author was privileged to accompany the expedition to the Galapagos Islands in 1931-1932.

References

* Hertlein, Leo George, and A. M. Strong. Marine pleistocene mollusks from the Galapagos islands. 1939. hancocki Gastropods described in 1939 {{Mangeliidae-stub