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Protatlanta souleyeti (Smith 1888)

Roger R. Seapy
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Containing group: Atlantidae

Introduction

Protatlanta souleyeti is a small species (<2 mm shell diameter) that is distinguished from all other atlantids by its calcareous shell and glass-like, cartilaginous keel, composed of conchiolin. The truncated keel extends from the shell aperture to about one-half of the shell's circumference in adult animals. The shell spire consists of three whorls and is slightly elevated and rounded, with incised sutures. In all P. souleyeti from the world oceans the shell spire lacks surface sculpture, although in the Atlantic Ocean there is a second form that has a low spiral ridge centered on the second whorl and extends to the third whorl, and a lower and shorter secondary spiral ridge inside the first one. The eyes lack a transverse slit in the distal pigmented tissue (type a, Richter, 1961), and the operculm has a large apical gyre (macro-oligogyre; type a, Richter, 1961). Geograpic distribution is cosmopolitan at tropical to subtropical latitudes.

Characteristics

  1. Shell
    1. Adult shell small (<2 mm), calcareous, and with a transparent cartilaginous keel of conchiolin (compare title illustration with first scanning electron micrograph below)  
    2. Keel tall and truncated, extending from the shell aperture to about one-half of the circumference of the shell
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      Click on an image to view larger version & data in a new window

      Figure. Scanning electron micrographs of the shell of Protatlanta souleyeti, viewed from the right side. Left: Low magnification; scale bar = 0.5 mm. Right: High magnification of the spire; scale bar = 0.1 mm. ©

      Figure. Scanning electron micrographs of the shell of Protatlanta souleyeti, tilted about 60°. Left: Low magnification view; scale bar = 0.5 mm. Right: High magnification view; scale bar = 0.1 mm.©

    3. Spire slightly elevated and rounded, with incised sutures, consisting of three whorls (see right photo above)
    4. Surface of spire whorls smooth (see high magnification views above), except for a variant with which it co-occurs in the Atlantic Ocean. In this form a low, spiral ridge is located in the middle of the whorl beginning on the second whorl and ends about three-fourths of a turn on the third whorl. A less conspicuous and shorter spiral ridge is located inside the primary ridge on the second whorl
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Shell spire of second form of Protatlanta souleyeti present in the Atlantic Ocean, having low, spiral sculpture on second and third whorls. Modified from Richter and Seapy (1999, fig. 5a). © 1999 G. Richter

    5. Shell aperture large, ovoid in shape (see second photo above)
    6. Umbilicus large (Tesch, 1949)
  2. Digestive gland, contained in the shell spire of adults, is brownish- to reddish-orange (see title illustration)
  3. Eyes type a; cuboidal in dorsal view, and with distal pigmented tissue lacking a transverse slit (after Richter, 1961)
  4. Operculum type a; macro-oligogyre, with a large gyre in the apical part of the operculum (after Richter, 1961)
  5. Radula large and triangular in shape. Central rachidian tooth monocuspid with a large, low basal plate. Lateral teeth monocuspid with a low process on the inner side. Marginal teeth monocuspid (Richter, 1961; Richter and Seapy, 1999)
  6. Larval shell with a smooth surface and a large ovoid aperture
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    Click on an image to view larger version & data in a new window

    Figure. Sketch of Protatlanta souleyeti larval shell in side or apertural view. Scale bar = 0.1 mm. Modified from Richter (1968, Fig. 6). © 1968 G. Richter

References

Richter, G. 1961. Die Radula der Atlantiden (Heteropoda, Prosobranchia) und ihre Bedeutung f?r die Systematik und Evolution der Famiie. Morphol. ?kol. Tiere 50: 163-238.

Richter, G. 1968. Heteropoden und Heteropodenlarven im Oberfl?chenplankton des Golfs von Neapel. Pubblicazioni della Stazione Zoologica di Napoli 36: 346-400.

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.

Tesch, J. J. 1949. Heteropoda. Dana Report, No. 34. 53 pp.

Title Illustrations
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Scientific Name Protatlanta souleyeti
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 Protatlanta souleyeti (Smith 1888). 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. . 2008. Protatlanta souleyeti (Smith 1888). Version 29 October 2008 (under construction). http://tolweb.org/Protatlanta_souleyeti/28754/2008.10.29 in The Tree of Life Web Project, http://tolweb.org/

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