Atlanta echinogyra Richter, 1972b

Overview

This is a medium sized dextrally shelled, pelagic snail, 0.3 cm in diameter with very large eyes, a single swimming fin. It is strongly flattened and keeled. The spire is violet, turrate with spiral lines, the rest of the shell is colourless. The operculum has a very small spire and a spiral line with hooks. It is a carnivore predating on relatively large zooplankton. This species occurs in warm waters of the Indian Ocean (Atlanta echinogyra 1, Atlanta echinogyra oral).

Taxonomic Description [after Richter, 1987]

Small, solid shell, the spire is moderately large, turrate with clear spiral sculpture. The suture is deep and clearly visible The spire is deep red-violet. The body whorl is inflated with a widening aperture. The inside of the aperture is darker in colour (Atlanta echinogyra). The inner whorls of the spire are not decalcified. The Atlanta echinogyra operculum (type C) is broad oval, monogyre, the nucleus has 15 to 20 strong hooks-shaped spines in spiral arrangement (Atlanta echinogyra operculum 1). The eyes (type A) have a cylindrical pigment mantle with triangular dorsal window. The radula is moderately large, ribbon-shaped. The median tooth is broad rectangular with a strong median cusp and side flaps. There is no sexual dimorphism in the radula.
Shell up to 2.5 mm in diameter.

Juveniles

The Atlanta echinogyra juvenile has a small dextrally coiled shell, with a smooth protoconch I and and three spiral lines composed of irregular crests and dots on the first three whorls of the spire (Atlanta echinogyra protoconch, Atlanta echinogyra protoc). Veliger with 3.5 whorls shows the beginning of the dorsal shell slit and flattened whorls.

Reproduction

In this species the sexes are separate.

Ecology

This species is carnivorous and epipelagic.

Distribution

This species occurs in the W-Indian and Pacific Oceans, see the Atlanta echinogyra map.

Types

Atlanta echinogyra Richter, 1972: 90, fig 3. 3, 5, 7.
Holotype: SMFM 223052. Paratypes: SMFM 223053.
Type locality: Indian Ocean. Coll.: CMEE.

Kingdom Animalia
Phylum Mollusca
Class Gastropoda
Subclass Streptoneura
Order Mesogastropoda
Superfamily Atlantacea
Family Atlantidae
Genus Atlanta
Species Atlanta echinogyra

Status in World Register of Marine Species

Not included in WoRMS database

Scientific synonyms and common names

Atlanta echinogyra Richter, 1972b

Synonyms

Atlanta inflata part Tokioka, 1961: 286
Atlanta echinogyra n. sp. Richter, 1972b: 90

Newman, L. J., 1990. Holoplanktonic molluscs (Gastropoda; Thecosomata, Gymnosomata, and Heteropoda) from the waters of Australia and Papua New Guinea: their taxonomy, distribution and biology. PhD Thesis Univ. Qld. Australia. 208 pp.

Richter, G., 1972b. Zur Kenntnis der Gattung Atlanta (Heteropoda: Atlantidae). Arch. Molluskenkunde 102(1-3): 85-91, 11 figs.

Richter, G., 1973b. Zur Stammesgeschichte pelagischer Gastropoden. Natur und Museum 103(8): 265-275, 4 tabs, 9 figs.

Richter, G., 1974. Die Heteropoden der 'Meteor' Expedition in den Indischen Ozean 1964/65. 'Meteor' Forschungserg. (D)17: 55-78, 8 figs, 3 pls.

Richter, G., 1987. Zur Kenntnis der Gattung Atlanta, 3. Atlanta inflata, A. helicinoides, A. echinogyra und A. plana (Prosobranchia: Heteropoda). Arch. Moll. 117(4-6): 177-201, 1 tab., 7 pls.

Seapy, R. R., 1986. The heteropod fauna of oceanic waters off Hawaii. West. Soc. Malac. 19: 9-13.

Seapy, R. R., 1990d. Sampling requirements for epipelagic heteropod molluscs. Amer. Malac. Bull. 8(1): 45-52.

Seapy, R. R., 1990e. The pelagic family Atlantidae (Gastropoda: Heteropoda) from Hawaiian waters: A faunistic survey. Malacologia 32(1): 107-103.

Seapy, R. R., 1996. Atlantid heteropods as living substrata for eggs of Halobates sericeus (Heteroptera: Gerridea). Pac. Sc. 50 (1): 84-92.

Tokioka, T., 1961. The structure of the operculum of the species of Atlantidae (Gastropoda: Heteropoda) as a taxonomic criterion, with records of some pelagic mollusks in the North Pacific. Publ. Seto mar. biol. Lab. 9(2): 267-332 (art. 15, pp. 1-86).

Spoel, S. van der, 1976c. Pseudothecosomata, Gymnosomata and Heteropoda. Bohn, Scheltema & Holkema, Utrecht. 484 pp. 246 figs.

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