Zoila

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Zoila
Housing of a Zoila friendii vercoi

Housing of a Zoila friendii vercoi

Systematics
Superordinate : Caenogastropoda
Order : Sorbeoconcha
Subordination : Hypsogastropoda
Superfamily : Cypraeoidea
Family : Cowries (Cypraeidae)
Genre : Zoila
Scientific name
Zoila
Jousseaume , 1884

Zoila is a genus from the family of cowries (Cypraeidae) whose living species occur exclusively in the Indian Ocean on the coasts of Australia.

biology

Like all other cowries, Zoilas have two separate sexes; in each species there are both male and female cowrie shells, which outwardly hardly differ from one another. The gonad of the snail produces either egg cells or sperm cells. After mating, the female deposits the clutch hidden in corals, empty mussels, Haliotis housings or similar. A clutch consists of about 200-300 egg pouches glued together with a diameter of about 3 mm and each containing 1000 eggs, so that a female produces about two hundred thousand eggs. Only one egg per egg pocket develops into an embryo, the other eggs are eaten by the offspring. The female stays with the brood for around 40 days, during which time the embryos develop into a snail with 2.5 coils. The operculum is still there and only disappears in the bulla stage of the growing snail. The color of the coat on most Zoila tends to be orange, whereas in adult animals the color changes and becomes grayish to black. The coat is fleshy, thick and translucent. All species have smooth and shiny housings, are callous (heavy, thick-walled) and are relatively large. The smallest species, Z. perlae , typically reaches a size of 35 to 62 mm, Z. thersites , the largest species, 60 to 116 mm.

Occurrence and habitat

Without exception, all rezent occurring Zoilas live in Australian waters. The distribution area extends along the coast including the offshore islands of the two territories Western Australia (WA) and South Australia (SA) over a distance of 4,000 kilometers. Fossilizations of extinct species can be found in other places: Z. caputavisensis in the Indonesian province of Papua, Z. kendengensis and Z. gendinganensis in Indonesia, Z. platypyga in Victoria (Australia) and Z. schilderi in India.

Today living species stay at depths of 2 m to more than 300 m, always on or in the immediate vicinity of sponges (Porifera). Presumably each species has populations that live in shallow waters (a few meters up to 50 m) as well as at greater depths (up to deeper than 300 m). The different housing features within a species suggest this. It is noteworthy that the appearance (shape, pigmentation, drawing and size) of the deeper species often only changes very slightly over hundreds of kilometers, whereas populations in shallower waters tend to form local forms.

Systematics

The genus was established in 1884 by the French doctor and mollusc researcher Félix Pierre Jousseaume . As a type species he chose Zoila scottii Broderip 1831 (synonym of Zoila friendii Gray, 1831). The species assigned to this genus were moved here from the genus Cypraea established by Linneus in 1758 . The use of the protonyms (for example ' Cypraea venusta ' instead of ' Zoila venusta ') is still to be found today by dealers and collectors. Incidentally, this applies not only to species of this genus, but to all species that are assigned to the Kauri family. The status of some of the living species is controversial. Some authors regard the species perlae , eludens and mariellae as a subspecies of decipiens , orientalis and ketyana as a subspecies of marginata and jeaniana as a subspecies of friendii .

Live species: Fossil species:

Incomplete list

Remarks

  1. ↑ Afrocypraea with the only species chubbi was set up by Schilder in 1932. Since A. chubbi is very similar to other extinct Zoilas and the author himself considered both genera to be closely related, this extinct species could possibly be taken into account in future, more recent classifications.
  2. ↑ Gigantocypraea Schilder 1927 is a subgenus

photos

  • Zoila decipiens

  • Zoila eludens

  • Zoila friendii

  • Zoila friendii vercoi

  • Zoila jeaniana aurata

  • Zoila Jeaniana Sherylae

  • Zoila ketyana hypermarginata

  • Zoila marginata

  • Zoila orientalis

  • Zoila Rosselli

  • Zoila thersites

literature

  • Felix Lorenz: Monograph Of The Living Zoila . ConchBooks 2001, Hackenheim. ISBN 3-925919-34-1
  • Schilder, FA & Schilder, M .: A catalog of living and fossil cowries . Memoirs Institut Royal Sciences Naturelle de Belgique. 1971

Web links

Commons : Zoila  - collection of images, videos and audio files

Individual evidence

  1. ↑ Biological Library (BioLib): Zoila
  2. ^ World Register of Marine Species: Zoila
  3. ^ Felix Lorenz: Monograph Of The Living Zoila . ConchBooks 2001, Hackenheim. ISBN 3-925919-34-1