Complete

Cardiapoda d'Orbigny 1836

Roger R. Seapy
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Containing group: Carinariidae

Introduction

The genus Cardiapoda is similar in general body shape to Carinaria, but differs most conspicuously in lacking a macroscopic shell that covers the visceral nucleus; instead the shell is microscopic (only slightly larger than the larval shell) and is imbedded in the dorsal portion of the digestive gland in the visceral nucleus.  Both the right and left tentacles are well-developed and of equal size, unlike Carinaria (in which the right tentacle is greatly reduced or vestigial) and Pterosoma (where the right tentacle is absent). The cutis is thin, unlike the thick, gelatinous cutis in Carinaria and Pterosoma.

Brief Diagnosis

A carinariid genus with:

Characteristics

  1. Body morphology
    1. Visceral nucleus not covered by shell, as in Carinaria and Pterosoma
    2. Gills either numerous, forming a crest on the visceral nucleus, or few, located at the entrance to the mantle cavity
    3. Visceral nucleus stalk directed posteriorly
    4. Right and left tentacles of equal size and well developed
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      Figure. Frontal view of Cardiapoda richardi. Note the prominent tentacles extending forward and outward from ahead of the eyes. © L. Madin

    5. Tail with a small dorsal crest (see C. richardi photo of tail below) and terminating either in a fan-shaped expansion that can be contracted or expanded (C. placenta; left) or a filamentous extension that can be greatly lengthened or shortened (C. richardi, right)
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      Figure. Lateral views of Cardiapoda placenta (left) and Cardiapoda richardi (right). © R. Gilmer and © L. Madin, respectively.  Note in the left photo the terminal posterior fan-shaped expansion, and in the right photo the low dorsal crest, the elongate mid-ventral slit, and the contracted reddish-brown filamentous tail extension.

    6. Cutis thin, in contrast with the thick, gelatinous cutis of Carinaria and Pterosoma
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      Click on an image to view larger version & data in a new window

      Figure. Trunk, swimming fin, head region and proboscis in Cardiapoda richardi. Note the folds in the thin cutis in the ventral part of the trunk and proboscis, resulting from ventral flexion of the proboscis. © L. Madin

  2. Shell
    1. The adult shell is microscopic and consists of the protoconch (the larval shell following metamorphosis) and a rudimentary teleoconch. The teleoconch is produced at right angles to the shell aperture, forming an outwardly-radiating shelf
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      Figure. Drawings of the microscopic adult shell in Cardiapoda placenta, viewed from the right side and aperture (left and right, respectively). Shell diameter about 0.8 mm. Drawings modified from Tesch (1949).

    2. Larval shell globular. Right side of shell with two spiral ridges on the second spire whorl. Left side of shell with umbilicus open and about 13 radiating ridges on umbilicus wall; aperture wide, slightly greater than 1/2 shell diameter
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      Click on an image to view larger version & data in a new window

      Figure. Scanning electron micrographs of the larval shell of Cardiapoda richardi, viewed from the right side, left side, and aperture.  Shell diameter = 0.6 mm. © R. Seapy

    3. With growth of the animal, the microscopic shell becomes imbedded in the digestive gland, with only the top of the protoconch visible

Comments

The genus Cardiapoda includes two species, which can be distinguished by the following characters:

Species Maximal body length
Number of gills
Location of gills
 Fin sucker
Structures at end of tail
Ventral tail structure
Eye morphology
C. placenta
ca. 110 mm
>20form a crest on  surface of visceral nucleus
present in both sexes
12 finger-like  expansions that can be  contracted or expanded, forming a fan
absent
shape triangular, as in other carinariids
C. richardi
ca. 30 mm
8at entrance to mantle cavity on visceral nucleus
present only in males
reddish-brown  filamentous tail extension
flat membranous structure that can be extended from elongate ventral slit
shape oval, with lens resting in cup of black pigmented tissue

References

Lalli, C. M. and R. W. Gilmer. 1989. Pelagic snails. The biology of holoplanktonic gastropod snails. Stanford University Press, Stanford. 259 pp.

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

Tesch, J. J. 1949. Heteropoda. Dana Report 34, 53 pp., 5 plates.

Title Illustrations
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Click on an image to view larger version & data in a new window
Scientific Name Cardiapoda placenta
Location Florida Current
Specimen Condition Live Specimen
Sex Female
Life Cycle Stage adult
View right side
Size 65 mm
Copyright © Ronald Gilmer
Scientific Name Cardiapoda richardi
Location Florida Current
Specimen Condition Live Specimen
Sex Female
Life Cycle Stage adult
View left side
Size 65 mm
Copyright © Ronald Gilmer
Scientific Name Cardiapoda richardi
Location Sargasso Sea
Specimen Condition Live Specimen
Sex Female
Life Cycle Stage adult
View ventral
Copyright © L. Madin
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 Cardiapoda d'Orbigny 1836. 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. Cardiapoda d'Orbigny 1836. Version 12 February 2008. http://tolweb.org/Cardiapoda/28742/2008.02.12 in The Tree of Life Web Project, http://tolweb.org/

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