Dicathais

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Dicathais
Dicathais orbita 2.JPG
Dorsal view of a shell of Dicathais orbita
Dicathais orbita (underside) 2.JPG
Apertural view showing the deep crenulations
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Caenogastropoda
Order: Neogastropoda
Family: Muricidae
Genus: Dicathais
Iredale, 1936  [1]
Species:
D. orbita
Binomial name
Dicathais orbita
(Gmelin, 1791)
Synonyms [1]
  • Buccinum orbita Gmelin, 1791
  • Dicathais aegrota(Reeve, 1846)
  • Dicathais scalaris(Menke, 1829)
  • Dicathais textilosa(Lamarck, 1816)
  • Dicathais vectorThornley, 1952)
  • Haustrum ventricosumKaicher, 1980
  • Neothais scalaris(Menke, 1829)
  • Polytropa succincta(Lamarck, 1816)
  • Purpura aegrotaReeve, 1846
  • Purpura scalarisMenke, 1829
  • Purpura succinctaLamarck, 1816
  • Purpura textilosaLamarck, 1816
  • Thais orbita(Gmelin, 1791)
  • Thais textilosa(Lamarck, 1816)

Dicathais is a genus of predatory sea snails, marine gastropod molluscs in the family Muricidae, the rock snails. This genus is monotypic; the only species in it is Dicathais orbita, common name the white rock shell or cart-rut shell, found round the coasts of Australia and New Zealand.

Contents

Description

The white rock shell is large with a strong shell usually about 6 centimetres (2.4 in) long, but occasionally growing to twice this size. It shows great variation in its shell sculpture across its range. In eastern Australia there are seven to nine deeply indented ribs in each whorl with clefts of a similar width between them, sculptured with further fine riblets. This gives a fluted edge to the lip and the grooves can also be seen on the interior surface of the shell. The central column or columella is smooth and the interior of the shell is white.

The western Australian form has a row of well marked nodules rather than ridges and an unindented lip while the southern Australian form has much less distinct ridges and a nearly smooth lip. [2] At one time it was thought that these different forms were distinct species but it has now been established that the variations in sculpture are a function of different living conditions. Specimens gathered from New South Wales with deep ridges were kept in a still water aquarium for three years during which time the new shell growth was at first shallowly indented and later was smooth. [2]

The colour of the shell is generally creamy white or grey, often with a thin yellowish line round the margin of the lip. [2] Juveniles have thinner shells and are often brown. [3]

Distribution and habitat

This snail is plentiful in the intertidal zone and sublittoral zone on rocks and among seaweed around the coasts of Australia (New South Wales, Queensland, South Australia, Tasmania, Victoria, Western Australia), New Zealand, Kermadec islands and Lord Howe Island. [3] [4]

Biology

The white rock shell is a predator, cannibal and scavenger. [5] It uses its radula to bore a hole in the shell of a barnacle or mollusc and then sucks out the contents. Prey species include the sea snails Lunella torquata , [2] Cronia avellana and Pyrene bidentata , and the mussel Septifer bilocularis . [5] As the tide rises, the white rock shell makes foraging expeditions up the beach, travelling far away from the sheltered niches to which it retreats at low tide. This is in contrast to the mulberry whelk Morula marginalba which shares the same habitat but remains in an area where there are both crevices in which to hide and prey species on which to feed. [6]

The sexes are separate in the white rock shell. The eggs that develop in the female gonoduct are wrapped in a number of membranes to form an egg capsule. Several of these are joined together in an egg mass and attached to the substrate. Different precursors of the pigment Tyrian purple have been found in the male and female gonoducts and in the egg capsule. [7] Early development of the larvae takes place inside the capsule which contains yolk granules on which they feed. When they have developed to the veliger stage, the larvae emerge from the capsule and become planktonic. After drifting with the currents for a while, these settle on the seabed, undergo metamorphosis and become juvenile snails. [8]

Related Research Articles

<span class="mw-page-title-main">Tyrian purple</span> Natural dye extracted from Murex sea snails

Tyrian purple, also known as, royal purple, imperial purple, or imperial dye, is a reddish-purple natural dye. The name Tyrian refers to Tyre, Lebanon. It is secreted by several species of predatory sea snails in the family Muricidae, rock snails originally known by the name Murex. In ancient times, extracting this dye involved tens of thousands of snails and substantial labor, and as a result, the dye was highly valued. The colored compound is 6,6′-dibromoindigo.

<span class="mw-page-title-main">Muricidae</span> Family of molluscs

Muricidae is a large and varied taxonomic family of small to large predatory sea snails, marine gastropod mollusks, commonly known as murex snails or rock snails. With over 1,700 living species, the Muricidae represent almost 10% of the Neogastropoda. Additionally, 1,200 fossil species have been recognized. Numerous subfamilies are recognized, although experts disagree about the subfamily divisions and the definitions of the genera. Many muricids have unusual shells which are considered attractive by shell collectors and by interior designers.

<i>Nucella</i> Genus of gastropods

Nucella, common name dog whelks or dog winkles, is a genus of small to medium-sized predatory sea snails, marine gastropod mollusks in the subfamily Ocenebrinae which is part of the large family Muricidae, the murex snails or rock snails.

<span class="mw-page-title-main">Knobbed whelk</span> Species of gastropod

The knobbed whelk is a species of very large predatory sea snail, or in the US, a whelk, a marine gastropod mollusk in the family Busyconidae, the busycon whelks.

<i>Busycon</i> Genus of busyconinin gastropods

Busycon is a genus of very large edible sea snails in the subfamily Busyconinae. These snails are commonly known in the United States as whelks or Busycon whelks. Less commonly they are loosely, and somewhat misleadingly, called "conchs".

<i>Rapana venosa</i> Species of gastropod

Rapana venosa, common name the veined rapa whelk or Asian rapa whelk, is a species of large predatory sea snail, a marine gastropod mollusc or whelk, in the family Muricidae, the rock shells.

<i>Thais</i> (gastropod) Genus of gastropods

Thais, sometimes known by the common names dog winkles or rock shells, is a genus of medium to large predatory sea snails with an operculum, marine gastropod mollusks in the family Muricidae.

<i>Haustrum haustorium</i> Species of gastropod

Haustrum haustorium, common name: the brown or dark rock shell, is a large species of predatory sea snail, a marine gastropod mollusc in the family Muricidae, the murex snails or rock snails.

<i>Haustrum</i> (gastropod) Genus of gastropods

Haustrum is a genus of sea snails, marine gastropod mollusks in the subfamily Haustrinae of the family Muricidae, the murex snails or rock snails.

<i>Stramonita haemastoma</i> Species of gastropod

Stramonita haemastoma, common name the red-mouthed rock shell or the Florida dog winkle, is a species of predatory sea snail, a marine gastropod mollusc in the family Muricidae, the rock snails.

<i>Chicoreus capucinus</i> Species of gastropod

The mangrove murex is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.

<i>Muricanthus radix</i> Species of gastropod

Muricanthus radix, the radix murex or root murex, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.

<i>Nucella lamellosa</i> Species of gastropod

Nucella lamellosa, commonly known as the frilled dogwinkle or wrinkled purple whelk, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails. This species occurs in the eastern Pacific Ocean, its range extending in the intertidal zone from the Aleutian Islands southward to central California.

<i>Nucella ostrina</i> Species of gastropod

Nucella ostrina, the northern striped dogwinkle, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails. Other common names for this mollusk include emarginate dogwinkle, short-spired purple dogwinkle, striped dogwinkle, ribbed dogwinkle, emarginate whelk, ribbed rock whelk, rock thais, short-spired purple snail and rock whelk.

<i>Neothais</i> Genus of gastropods

Neothais is a genus of sea snails, marine gastropod mollusks in the subfamily Rapaninae of the family Muricidae, the murex snails or rock snails.

The hypobranchial gland is a glandular structure which is part of the anatomy of many mollusks, including several different families of gastropods, and also many protobranch bivalves. This gland produces mucus as well as biologically active compounds. The cephalopod ink sac is a modified hypobranchial gland.

<i>Cominella lineolata</i> Species of gastropod

Cominella lineolata, common name the spotted cominella, is a species of predatory sea snail, a marine gastropod mollusc in the family Cominellidae,.

<i>Oppomorus noduliferus</i> Species of gastropod

Oppomorus noduliferus, common name the nodule castror bean, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.

<i>Nassarius pauperatus</i> Species of gastropod

Nassarius pauperatus, commonly known as the impoverished dog whelk, is a species of sea snail, a marine gastropod mollusk in the family Nassariidae, the nassa mud snails, or dog whelks.

<i>Tenguella marginalba</i> Species of gastropod

Tenguella marginalba is a species of sea snail, a marine gastropod mollusc in the family Muricidae, the murex snails or rock snails. It is commonly known as the mulberry whelk and is found in shallow waters in the Indo-Pacific and around the north and east coasts of Australia.

References

  1. 1 2 Roland Houart (2010). "Dicathais Iredale, 1936". WoRMS. World Register of Marine Species . Retrieved June 1, 2012.
  2. 1 2 3 4 Des Beechey (2000). "Dicathais orbita (Gmelin, 1791)". Seashells of New South Wales. Retrieved June 1, 2012.
  3. 1 2 Grove, Simon. "Muricidae – Rapaninae: Dicathais orbita (Gmelin, 1791)". A guide to the seashells and other marine molluscs of Tasmania. Retrieved June 1, 2012.
  4. Hardy, Eddie (2011). "Dicathais orbita". Hardy's Internet Guide to Marine Gastropods. Retrieved 2012-05-05.
  5. 1 2 Morton, B.; Britton, J. C. (1993). "The ecology, diet and foraging strategy of Thais orbita (Gastropoda: Muricidae) on a rocky shore of Rottnest Island, Western Australia". Western Australia Museum: 539–563.{{cite journal}}: Cite journal requires |journal= (help)[ permanent dead link ]
  6. Fairweather, P. G. (1988). "Movements of intertidal whelks (Morula marginalba and Thais orbita) in relation to availability of prey and shelter". Marine Biology. 100 (1): 63–68. doi:10.1007/BF00392955. S2CID   84570600.
  7. Westley, C. B.; Benkendorff, K. (2008). "Sex-Specific Tyrian Purple Genesis: Precursor and Pigment Distribution in the Reproductive System of the Marine Mollusc, Dicathais orbita". Journal of Chemical Ecology. 34 (1): 44–56. doi:10.1007/s10886-007-9402-2. PMID   18075711. S2CID   5111164.
  8. Westley, C. B.; Benkendorff, K. (2008). "Egg capsule formation and the origin of vitellus in Dicathais orbita" (PDF). Invertebr. Reprod. Dev.