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Atlanta Lesueur, 1817

Roger R. Seapy
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taxon links [up-->]Atlanta gaudichaudi [up-->]Atlanta lesueurii [up-->]Atlanta brunnea [up-->]Atlanta echinogyra [up-->]Atlanta rosea [up-->]Atlanta oligogyra [up-->]Atlanta inflata [up-->]Atlanta fragilis [up-->]Atlanta turriculata [up-->]Atlanta californiensis [up-->]Atlanta helicinoidea [up-->]Atlanta peronii [up-->]Atlanta frontieri [up-->]Atlanta plana [down<--]Atlantidae Interpreting the tree
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Containing group: Atlantidae

Introduction

Atlanta is the type genus of the Atlantidae, containing all but two of the species in the family (the other two genera, Protatlanta and Oxygyrus, are monospecific). The shell and keel are calcareous (composed of aragonite). The larval shell is retained following metamorphosis, becoming the spire in the adult shell. All species but one, A. californiensis in the temperate North Pacific, dwell in tropical to subtropical waters. The geographic distribution of most species (10) are cosmopolitan, being found in all three main oceans. Among the remaining species, four are Indo-Pacific, two are restricted to the Indian Ocean, one to the Atlantic, two to the Atlantic and Indian Oceans, and two to the Pacific Ocean.

Brief Diagnosis

An atlantid with:

Characteristics

  1. Eye morphology of three types: a, b and c (see Atlantidae page)
  2. Operculum morphology of three types: a, b, c (see Atlantidae page)
  3. Radular morphology of two types: I and II (see Pterotracheoidea page)
  4. Shell
    1. The shell consists of three sequentially-deposited portions; a dome-shaped embryonic shell (protoconch I) of about one whorl (below left), a larval shell (protoconch II) of a variable number of whorls (below middle), and the adult shell (teleoconch) of a variable number of whorls (below right)
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      Figure. Scanning electron micrographs of the embryonic portion (protoconch I) of the larval shell (left), the larval shell (protoconch II; middle), and the adult shell (right) in Atlanta plana. Note that in the last SEM the protoconch is shaded blue to distinguish it from the teleoconch. Scale bars = 100 µm (middle) and 0.5 mm (right). © 2005

    2. Spire whorl number. The number of whorls comprising the spire of the adult shell (the protoconch) is constant, while the number of whorls in the teleoconch increases with shell growth (see above right). The size of the teleoconch whorls (reflected in the width of the whorls when the shell is viewed from the right side) increases rapidly with growth. Thus, the approximate location on the shell where the narrow whorls of the protoconch end and the rapidly increasing width of the teleoconch whorls begin is easily determined under a dissection microscope. The whorl number ranges from two and one-half (Atlanta lesueurii and A. oligogyra) to six (A. gibbosa) (see table below)
    3. Spire shape and ornamentation.  Spire shape is highly variable and can often serve as a distinctive species and species group (see below) characterisitic. Examples include the tall, turreted spire of A. turriculata, the tilted (or "inclined") spire in the A. inclinata and A. gibbosa species groups, and the large, low rounded and elevated spire of A. inflata and A. helicinoidea.  Similarly, spire ornamentation can be very distinctive, ranging from smooth (e.g., the A. lesueurii species group and three of the members of the A. peronii species group) to ornamented by low, elevated spiral ridges (e.g., A. inflata, A. helicinoidea, and A. plana) and highly ornate elevated sculpture (e.g., A. brunnea, A. echinogyra and A. turriculata).

  5. Nineteen species are currently regarded as valid in the genus Atlanta. These species are partitioned into seven species groups (see table below). Tesch (1908) was the first to group together the species of Atlanta sharing similar morphologies. He recognized four species groups; the A. peronii-, A. inflata-, A. turriculata-, and A. inclinata-groups. In addition to these four groups, three additional ones are currently recognized; the A. lesueurii-, A. gaudichaudi- and A. gibbosa groups. Except for Tesch's A. turriculata-group, the composition of Tesch's species groups has changed by species invalidations, addition of new species over time, and addition of three new species groups. The main changes in Tesch's species groups have occurred in the A. peronii-group (A. gaudichaudi and A. lesueurii now form their own species groups) and the A. inclinata-group (A. gibbosa now forms its own group).

    One species, A. peresi, is not included in the table below because its validity is highly questionable. It was described by Frontier (1966) from the western Indian Ocean off Madagascar. Although its adult shell morphology and opercular type were characterized by Frontier, its eye and radular morphologies are unknown. Unfortunately, no specimens from Frontier's collections have been found for further examination. C. Thiriot (pers. comm. to R. Seapy) had thought that Frontier's collections might have been deposited at the Observatoire Océanologique, Villefranche-sur-Mer, France; but her search for the collections there proved futile. Richter (1974) concluded that there was substantial doubt that A. peresi was a valid species after his examination of the heteropods from the extensive collections of the Meteor Expedition in 1964-1965 to the northwestern Indian Ocean, including the Arabian Sea. In addition, examination of planktonic and benthic samples collected off western Australia by Seapy et al. (2003) did not record any specimens that could be identified as A. peresi. There have been no records of the species from the Pacific Ocean (Seapy, 1990a,b and 2008; Newman, 1990), although it was identified from the North Atlantic by Thiriot-Quiévreux (1968, 1970 and 1973). However, she subsequently concluded that her identifications were erroneous (R. Seapy, pers. comm.). The interested reader is referred to Richter and Seapy (1999: 640) for a further description and discussion of this problematic species.

    The geographic distribution of the species in the genus are summarized in the last three columns of the table below. The highest number of species occurs in the Pacific (17), followed by the Indian (16) and the Atlantic (12) Oceans. Ten species are cosmopolitan, recorded from all three major oceans, while five (A. turriculata, A. frontieri, A. plana, A. echinogyra, and A.gibbosa) are Indo-Pacific and one is Indo-Atlantic (A. selvagensis). Two species (Atlanta inflata and A. californiensis) only occur in the Pacific, and one (A. fragilis) is found only in the Atlantic; no species are unique to the Indian Ocean. In should be noted that one species, A. meteori was previously regarded as Indo-Pacific, but it was recorded from the northeastern Atlantic by de Vera, et al. (2006) and must now be treated as cosmopolitan.

    The seven species groups, their contained species, and the distinguishing features of each group and species are presented in the table below. The species comprising each species group share the same radular type, usually the same opercular type, and, in many cases, the same eye type.
Species group Group characteristics Species* Species characteristics Shell diameter (except keel) Number of spire whorls Eye type Opercular type Radular type Atlantic Ocean
Pacific Ocean
Indian Ocean
A. brunnea-
group
Shell small with tall, rounded keel; spire strongly elevated and sculptured, with complex ornamentation and a prominent spiral ridge; color darkens with age A. brunnea
Spire tall conical; color yellowish-brown to dark brown; circumglobal <2 mm 4 a a
I
 +  +  +
A. turriculata Spire tall, turreted; spire color yellowish- to reddish-brown and grading into clear outer shell whorl; Indo-Pacific <2 mm 4-1/4 a a
I
 -  +  +
A. inflata- group Shell either inflated (width ca. 40% of shell diameter) or flat; spire large (relative to shell size) and low with shallow sutures or small and low; spire surface smooth to sculptured (with evenly-spaced spiral ridges) A. inflata Shell spire low conical, with low spiral ridges, varible in expression; spire sutures lack coloration; keel tall with truncate leading edge; keel base yellow-brown to brown; Pacific Ocean <1.5 mm 4-1/4 to 4-1/2 a c
I
 -  +  -
A. selvagensis Shell spire low conical, with low spiral ridges, variable in expression; spire sutures reddish-brown; keel base yellow-brown to brown; Atlantic and Indian Oceans
<2 mm 3-1/2 to 3-3/4
a
c
I
 +  -  +
A. helicinoidea Body whorl of shell nearly circular in cross section; keel of low to moderate height, rounded; spire large with  spiral ridges, somewhat variable in expression; spire light purple or yellow to yellow-tan; circumglobal <2 mm 4-1/2 to 4-3/4
c c
I
 +  +  +
A. californiensis Shell flattened; keel of moderate height, truncate, and with red-brown base; spire small (relative to shell size), low conical to globular, and smooth; colorless to uniformly or mottled, light yellow, brown or violet; North Pacific Ocean <3.5 mm 3-1/4 a c
I
 -  +  -
A. lesueurii- group Shell spire very small; after larval metamorphosis, only a single and rapidly-expanding last whorl (teleoconch) is formed
A. lesueurii Shell entirely transparent; spire low and conical with prominent (deep) sutures; keel high, truncate; circumglobal <6 mm 2-1/2 b b
I
 +  +  +
A. oligogyra Shell faint pink to yellow; spire low and rounded with shallow sutures: keel of moderate height, rounded; circumglobal <3 mm 2-1/2 a b
I
 +  +  +
A. peronii- group Shell flat, of moderate to large size; spire small A. peronii Spire low, rounded; keel of moderate height, truncate; shell colorless, becoming faintly yellow in large specimens; circumglobal <10 mm 3-1/2 b b
II
 +  +  +
A. fragilis Shell fragile (thin-walled), transparent and completely colorless; keel high; Atlantic Ocean <9 mm 3-1/2 b II
 +  -  -
A. rosea Spire nearly globular; spire whorls difficult to distinguish due to extremely shallow sutures of first two and one-half whorls; color faintly yellow; species name based on bright pink larval shell; circumglobal <5 mm 3-1/2 b b
II
 +  +  +
A. frontieri Spire low, with first and second whorls elevated, forming a low cone; distinctive thin, elevated spiral ridge along outer margin of spire whorls; keel of moderate height, rounded; colorless; Indian Ocean <5.5 mm 4-1/2 b b
II
 -  +  +
A. gaudichaudi- group Shell flat; shell spire small, with low conical shape
A. gaudichaudi Spire smooth; keel of moderate height, truncate and with a brown base; shell colorless; circumglobal <3 mm 3-1/4 b b
I
 +  +  +
A. plana Spire low conical with weak, spiral ridges; spire sutures violet; keel moderately low and rounded, with a brown base; Indo-Pacific <3.5 mm 3-1/2 a b
I
 -  +  +
A. echinogyra Spire low conical, slightly tilted relative to shell plane, with  prominent spiral ridges and secondary sculpture; spire reddish-brown and teleoconch colorless; Indo-Pacific <2.5 mm 3-3/4 a c
I
 -  +  +
A.inclinata- group Shell spire large, globose (bee-hive shaped), strongly inclined relative to shell plane, with shallow sutures and numerous small tuberculae on the surface; keel moderately high and rounded; internal shell wall of radially-arranged lines A. inclinata Spire with small tuberculae scattered on surface; spire weak rose color and last shell whorl colorless; circumglobal <7 mm 4-1/2 b c
II
 +  +  +
A. tokiokai Spire with spirally-arranged rows of low tuberculae; colorless to light yellow; circumglobal <3 mm 5-1/2 b c
II
 +  +  +
A. gibbosa- group Shell spire large and high; internal shell wall without radially-arranged lines; shell completely transparent and colorless A. gibbosa Spire moderately inclined relative to shell plane, with a broad base and pointed apex; circumglobal? (presence in Atlantic Ocean uncertain) <4 mm 6 b b
II
 -?  +  +
A. meteori Spire strongly inclined relative to shell plane, conical and steep sided; keel high, truncate; circumglobal <4 mm 5-3/4 b b
II
 +  +  +

Comments

Noteworthy changes have been made in the authorship (and in some cases the spelling or, in the case of Atlanta brunnea, a change in the specific epithet) of seven species in the genus Atlanta that were originally described by Souleyet (1852) in a chapter on the Heteropoda collected from the Bonite Expedition of 1836/1837. Souleyet gave vernacular and species names (e.g., 'Atlante de Gaudichaud' and 'Atlanta Gaudichaudii, nobis'). However, J. E. Gray had earlier latinized Souleyet's vernacular names in an "Explanation of Plates" that was part of the third (1850) of a five volume (1842-1857) collection of illustrations copied by his wife, M. E. Gray from the then-existing literature, which included those from an Eydoux and Souleyet atlas of 1841? (for a more complete discussion, see the Preface in Janssen and Seapy, 2009). As a result, J. E. Gray formally became the author of all but one (A. gibbosa) of Souleyet's species. The affected species include:

References

Eydoux, F. and L. F. A. Souleyet. 1841(?). Voyage autour du monde execute pendant les annees 1836 et 1837 sur la corvette 'La Bonite', commandee par m. Vaillant, capitaine de vaisseau, publie par ordre du Gouvernement sous les auspices du Departemente des las Marine. Histoire Naturelle, Zoologie Atlas, 8 pp. Paris

Frontier, S. 1966. Notes morphologiques sur les Atlanta récoltées dans le plancton de Nosy Bé (Madagascar). Cah. ORSTOM, Sér. Océanogr. 4: 131-139.

Gray, J. E. 1850. Explanation to the plates. In: Gray, M. E., Figures of molluscous animals selected from various authors, etched for the use of students. Vol. 4, 124 pp. Longman, Brown, Green and Longmans, London.

Janssen, A. W. and R. R. Seapy. 2009. On the identity and distribution of Atlanta inflata Gray, 1850 (Gastropoda, Pterotracheoidea, Atlantidae) in the world's oceans. Basteria 73: 139-157.

Richter, G. 1961. Die Radula der Atlantiden (Heteropoda, Prosobranchia) und ihre Bedeutung für die Systematik und Evolution der Famiie. Zeitschrift f?r Morphologie und ?kologie das Tiere: 163-238.

Richter, G. 1974. Die Heteropoden der "Meteor"-Expedition in den Indischen Ozean, 1964/65. "Meteor" Forschungs-Ergebnisse 17(D): 55-78.

Richter, G. and R. R. Seapy. 1999. Heteropoda, pp. 621-647. In: D. Boltovskoy (ed.), South Atlantic Zooplankton. Leiden: Backhuys Publ.

Seapy, R. R. 1990. The pelagic family Atlantidae (Gastropoda: Heteropoda) from Hawaiian waters: a taxonomic survey. Malacologia 32: 107-130.

Seapy, R. R., C. M. Lalli and F. E. Wells. 2003. Heteropoda from western Australian waters, pp. 513-546. In: F. E. Wells, D. I. Walker and D. S. Jones (eds.), The marine flora and fauna of Dampier, Western Australia. Perth: Western Australia Museum.

Souleyet, [L. F. A.] 1852. In: Eydoux, [F.] and Souleyet [L. F. A.], Voyage autour du monde execute pendant les annees 1836 et 1837 sur la corvette 'La Bonite'... Zoologie, col. 2. 664 pp. A. Bertrand, Paris.

Thiriot-Quievreux, C. 1968. Variations saisonnieres des Mollusques dans le plancton de la region de Banyuls-sur-Mer (Zone sud du Golfe du Lion) Novembre 1965 - Decembre 1967. Vie et Milieu, Serie B, 19: 35-83.

Thiriot-Quievreux, C. 1970. Cycles annuels des populations planctoniques de Mollusques en 1968 dans la region de Banyuls-sur-Mer. Cmmparisison avec les annees precedentes 1965-1967 Vie Milieu, Series B, 21: 311-335.

Thiriot-Quievreux, C. 1973. Heteropoda. Oceanography and Marine Biology Annual Review 11: 237-261.

Vera, de A., R. R. Seapy, and F. Hernandez. 2006. Heteropod molluscs from waters around the Selvagens Islands (Gastropoda: Carinarioidea). Vieraea 34: 33-43.

Title Illustrations
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Scientific Name Atlanta peronii
Location Hawaiian waters
Specimen Condition Live Specimen
Sex Female
Life Cycle Stage adult
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About This Page


California State University, Fullerton, California, USA

Correspondence regarding this page should be directed to Roger R. Seapy at

Page: Tree of Life Atlanta Lesueur, 1817. Authored by Roger R. Seapy. The TEXT of this page is licensed under the Creative Commons Attribution License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Seapy, Roger R. 2010. Atlanta Lesueur, 1817. Version 01 April 2010 (under construction). http://tolweb.org/Atlanta/28752/2010.04.01 in The Tree of Life Web Project, http://tolweb.org/

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