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Systematic comparison and reconstruction of sea urchin (Echinoidea) internal anatomy: a novel approach using magnetic resonance imaging.

Ziegler A, Faber C, Mueller S, Bartolomaeus T - BMC Biol. (2008)

Bottom Line: Based on the acquired datasets, interactive three-dimensional models were assembled.Our analyses reveal that selected soft tissue characters can even be used for phylogenetic inferences in sea urchins, as exemplified by differences in the size and shape of the gastric caecum found in the Irregularia.The main focus of our investigation was to explore the possibility to systematically visualize the internal anatomy of echinoids obtained from various museum collections.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut für Biologie, Freie Universität Berlin, Königin-Luise-Strasse, 14195 Berlin, Germany. aziegler@zoosyst-berlin.de

ABSTRACT

Background: Traditional comparative morphological analyses and subsequent three-dimensional reconstructions suffer from a number of drawbacks. This is particularly evident in the case of soft tissue studies that are technically demanding, time-consuming, and often prone to produce artefacts. These problems can partly be overcome by employing non-invasive, destruction-free imaging techniques, in particular micro-computed tomography or magnetic resonance imaging.

Results: Here, we employed high-field magnetic resonance imaging techniques to gather numerous data from members of a major marine invertebrate taxon, the sea urchins (Echinoidea). For this model study, 13 of the 14 currently recognized high-ranking subtaxa (orders) of this group of animals were analyzed. Based on the acquired datasets, interactive three-dimensional models were assembled. Our analyses reveal that selected soft tissue characters can even be used for phylogenetic inferences in sea urchins, as exemplified by differences in the size and shape of the gastric caecum found in the Irregularia.

Conclusion: The main focus of our investigation was to explore the possibility to systematically visualize the internal anatomy of echinoids obtained from various museum collections. We show that, in contrast to classical preparative procedures, magnetic resonance imaging can give rapid, destruction-free access to morphological data from numerous specimens, thus extending the range of techniques available for comparative studies of invertebrate morphology.

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Overview chart showing analyzed specimens of irregular sea urchins and corresponding 3D reconstructions of selected internal organs. (A) Information on species name, geographic distribution, and systematics. (B) Photograph of scanned specimen, aboral view. (C)-(E) 3D models of reconstructed selected internal organs, stepwise turned by 90°: (C) aboral view (ambulacrum III facing to the right); (D) lateral view (ambulacrum III facing to the right); (E) oral view (ambulacrum III facing to the right). Scale bar: 1 cm, except for Echinocyamus pusillus: 1 mm. The colour legend specifies organ designation.
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Figure 4: Overview chart showing analyzed specimens of irregular sea urchins and corresponding 3D reconstructions of selected internal organs. (A) Information on species name, geographic distribution, and systematics. (B) Photograph of scanned specimen, aboral view. (C)-(E) 3D models of reconstructed selected internal organs, stepwise turned by 90°: (C) aboral view (ambulacrum III facing to the right); (D) lateral view (ambulacrum III facing to the right); (E) oral view (ambulacrum III facing to the right). Scale bar: 1 cm, except for Echinocyamus pusillus: 1 mm. The colour legend specifies organ designation.

Mentions: The 3D reconstructions presented here are limited to the major soft tissue structures identifiable in all datasets, if present in the respective species (Figure 3C–E and 4C–E): digestive tract, Stewart's organs, axial complex, siphon, gonads, buccal sacs (or 'gills') and gastric caecum.


Systematic comparison and reconstruction of sea urchin (Echinoidea) internal anatomy: a novel approach using magnetic resonance imaging.

Ziegler A, Faber C, Mueller S, Bartolomaeus T - BMC Biol. (2008)

Overview chart showing analyzed specimens of irregular sea urchins and corresponding 3D reconstructions of selected internal organs. (A) Information on species name, geographic distribution, and systematics. (B) Photograph of scanned specimen, aboral view. (C)-(E) 3D models of reconstructed selected internal organs, stepwise turned by 90°: (C) aboral view (ambulacrum III facing to the right); (D) lateral view (ambulacrum III facing to the right); (E) oral view (ambulacrum III facing to the right). Scale bar: 1 cm, except for Echinocyamus pusillus: 1 mm. The colour legend specifies organ designation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2500006&req=5

Figure 4: Overview chart showing analyzed specimens of irregular sea urchins and corresponding 3D reconstructions of selected internal organs. (A) Information on species name, geographic distribution, and systematics. (B) Photograph of scanned specimen, aboral view. (C)-(E) 3D models of reconstructed selected internal organs, stepwise turned by 90°: (C) aboral view (ambulacrum III facing to the right); (D) lateral view (ambulacrum III facing to the right); (E) oral view (ambulacrum III facing to the right). Scale bar: 1 cm, except for Echinocyamus pusillus: 1 mm. The colour legend specifies organ designation.
Mentions: The 3D reconstructions presented here are limited to the major soft tissue structures identifiable in all datasets, if present in the respective species (Figure 3C–E and 4C–E): digestive tract, Stewart's organs, axial complex, siphon, gonads, buccal sacs (or 'gills') and gastric caecum.

Bottom Line: Based on the acquired datasets, interactive three-dimensional models were assembled.Our analyses reveal that selected soft tissue characters can even be used for phylogenetic inferences in sea urchins, as exemplified by differences in the size and shape of the gastric caecum found in the Irregularia.The main focus of our investigation was to explore the possibility to systematically visualize the internal anatomy of echinoids obtained from various museum collections.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut für Biologie, Freie Universität Berlin, Königin-Luise-Strasse, 14195 Berlin, Germany. aziegler@zoosyst-berlin.de

ABSTRACT

Background: Traditional comparative morphological analyses and subsequent three-dimensional reconstructions suffer from a number of drawbacks. This is particularly evident in the case of soft tissue studies that are technically demanding, time-consuming, and often prone to produce artefacts. These problems can partly be overcome by employing non-invasive, destruction-free imaging techniques, in particular micro-computed tomography or magnetic resonance imaging.

Results: Here, we employed high-field magnetic resonance imaging techniques to gather numerous data from members of a major marine invertebrate taxon, the sea urchins (Echinoidea). For this model study, 13 of the 14 currently recognized high-ranking subtaxa (orders) of this group of animals were analyzed. Based on the acquired datasets, interactive three-dimensional models were assembled. Our analyses reveal that selected soft tissue characters can even be used for phylogenetic inferences in sea urchins, as exemplified by differences in the size and shape of the gastric caecum found in the Irregularia.

Conclusion: The main focus of our investigation was to explore the possibility to systematically visualize the internal anatomy of echinoids obtained from various museum collections. We show that, in contrast to classical preparative procedures, magnetic resonance imaging can give rapid, destruction-free access to morphological data from numerous specimens, thus extending the range of techniques available for comparative studies of invertebrate morphology.

Show MeSH
Related in: MedlinePlus