Guildfordia Yoka Shell highly sought by collectors

Guildfordia Yoka Shell
10/23/13

Guildfordia Yoka Shell

Guildfordia yoka, the yoka star turban, are deep-water sea snails, marine gastropod mollusks, in the family Turbinidae, the turban snails.

These tropical marine species are found in the Western Pacific off Japan and the Philippines, living at depths between 660 to 1,640 feet.

The Guildfordia Yoka grows to an average of 2 1/2 to 4 inches. The color pattern of the shell ranges from very light brownish to purple-brown. Some specimens contain only 6 whorls instead of 7 as in the holotype. The upper whorls are smooth, then follows the body whorl with 2 rows of granules, instead of 7 or 8. The Guildfordia Yoka keel has irregular radiating ribs, which leave a nearly smooth zone above the keel, with only a few spiral striae.

The base of the shell is less convex than the upper part. Some specimens lack the rose-colored line around the umbilical callosity. The aperture is oval & thick, with the nucleus in the external lower corner. The outer surface is rugose, by irregular wrinkles, nearly parallel with the basal margin of the operculum. The nucleus is marked by an olive spot.

Embryos of Guildfordia Yoka develop into free-swimming planktonic larvae with several bands of cilia (trochophore). Later they develop into juvenile veligers, finally into fully grown adults.

(REF G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia) (REF: Beu, A. G. (1970). Descriptions of new species and notes on taxonomy of New Zealand Mollusca. Transactions of the Royal Society of New Zealand, Earth Science.)

Scientific classification

Domain: Eukaryota

Kingdom: Animalia

Phylum: Mollusca

Class: Gastropoda

Subclass: Vetigastropoda

Order: Trochida

Super family: Trochoidea

Family: Turbinidae

Genus: Guildfordia

Gray, 1850

Type species: Trochus triumphans

Philippi, 1841

GY-17

One Guildfordia Yoka shell, measuring 2 3/4 to 3 inches....... $2.49




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