Under Construction

This is an archived version of a Tree of Life page. For up-to-date information, please refer to the current version of this page.

Containing group: Atlanta

Introduction

Atlanta rosea attains a moderately large size (to 5 mm). Its shell morphology is very similar with that of A. peronii, with which it was synonymized in 1908 and remained so until 1993, when it was shown to be a valid species. The distinguishing features of its shell that separate it from other members of the A. peronii species group are the low rounded (or globular) spire and the very shallow spire sutures of the first 2-1/2 whorls. The shell is transparent to faintly yellow. The body coloration and keel base are rose colored, according to Souleyet who described the species in 1852. The larva is bright pink, which distinguishes it from the larvae of other species in the A. peronii species group. Eyes type b. Operculum type b. Radula type II. The species is circumglobal in tropical to subtropical waters, and is regarded as rare. Nothing is known of its vertical distribution.

Characteristics

1. Shell
   1. Shell moderately large (to 5 mm diameter)
   2. Shell transparent to faintly yellow
      
   3. Spire rounded, approximately globular in shape
      
   4. Spire consists of about 3-1/2 whorls, with suture separating the first 2-1/2 whorls very shallow; the result being a nearly smooth spire surface (see second SEM and larval shell photographs below)
   5. Keel inserts between penultimate and last whorls in shells larger than about 1.5 mm (see first SEM below)
      

      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. Scanning electron micrographs of the shell of Atlanta rosea viewed from the right side (left) and the central part of the spire (right). Shell diameter = 3.0 mm. From Richter (1993, figs. 4 and 8, respectively). © 1993 G. Richter
      

      

      Click on an image to view larger version & data in a new window

      
      

      Figure. Scanning electron micrograph of the Atlanta rosea shell shown above in tilted view. Shell diameter = 3.0 mm. From Richter and Seapy (1999, fig. 7C) (© 1999 G. Richter

   6. Larval shell with somewhat elongatel aperture and rounded, globular spire
      
      

      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. Scanning electron micrograph of the larval shell in Atlanta rosea in apertural view. From Richter (1993, fig. 7). Shell diameter = 245 µm. © 1993 G. Richter

   7. Larval shell with a bright pink tinge, which immediately distinguishes it from the larvae of others in the Atlanta peronii species group (Richter and Seapy, 1999)
      
      
2. Body coloration rose colored, as is the keel base (Souleyet, 1852). The following photograph was taken of a live specimen collected in Hawaiian waters and tentatively identified as A. peroni?; unfortunately it was not retained for later identification. I have subsequently suspected that it might be A. rosea because of the rose coloration of the body (particularly the spire region) and the keel base.
   
   

   Click on an image to view larger version & data in a new window

   
   

   Figure. Photograph of a specimen of Atlanta collected from Hawaiian waters; possibly A. rosea. Note the pinkish, or rose, coloration of the keel base continuous with the spire sutures. ©

3. Eyes type b
4. Operculum type b
5. Radula type II

Comments

Souleyet described Atlanta rosea (under the vernacular name Atlante rose) from specimens collected by the Bonite Expedition in the western Pacific Ocean. He regarded A. rosea as most closely related to A. peronii, citing a larger spire size in A. rosea, and naming the species on the basis of the rose color of the body and keel base. Tesch (1906, p. 10) reported A. rosea from samples collected during the Siboga Expedition to the East Indies. However, in his revision of the genus Atlanta in 1908, Tesch rejected A. rosea as a valid species, designating it as a junior synonym of A. peronii. Subsequent authors (notably Tesch, 1949 and van der Spoel, 1976) accepted Tesch's merger of A. rosea with A. peronii.  But in a 1993 paper on the species comprising the A. peronii species group, Richter (1993) provided conclusive proof that Souleyet was correct in treating A. rosea as species distinct from A. peronii. The primary difference in the shells was in the rounded spire shape and shallow suture in the early spire whorls of A. rosea. These differences in the spires of A. rosea and A. peronii are clearly seen by Richter's dark field photographs of the larval shells of the two species in apertural view (see below).

In a paper on the heteropods of the South Atlantic Ocean, Richter (in Richter and Seapy, 1999: 638) stated that "in 1908 Tesch united A. rosea with A. peroni probably because the holotypes in the Musee d'Histoire Naturelle de Paris were already badly damaged (shells dissolved) when he had the opportunity to study them. Comparing "aberrant" shells of A. peroni from the Indian Ocean and the tropical Atlantic Ocean with the type shells of Souleyet, preserved dry in the British Museum, London, Richter (1993) found that they belonged to this very species.

Other Names for Atlanta rosea Gray 1850

• Atlanta rosea Souleyet 1852

References

Richter, G. 1993. Zur Kenntnis der Gattung Atlanta (V). Die Atlanta peroni-Gruppe und Atlanta gaudichaudi (Prosobranchia: Heteropoda). Archiv fur Molluskenkunde 122: 189-205.

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

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.

Spoel, S. van der. 1976. Pseudothecosomata, Gymnosomata and Heteropoda (Gastropoda). Bohn, Scheltema & Holkema, Utrecht. 484 pp.

Tesch, J. J. 1906. Die Heteropoden der Siboga-Expeditie. Monographie 51, 112 pp. E. J. Brill, Leiden.

Tesch, J. J. 1908. Systematic monograph of the Atlantidae (Heteropoda) with enumeration of the species in the Leyden Museum. Notes from the Leyden Museum 30: 1-30, 5 plates.

Tesch, J. J. 1949. Heteropoda. Dana Report 34: 1-54.