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Brain anatomy in Diplura (Hexapoda).

Böhm A, Szucsich NU, Pass G - Front. Zool. (2012)

Bottom Line: In the past decade neuroanatomy has proved to be a valuable source of character systems that provide insights into arthropod relationships.In contrast, Archaeognatha completely lack mushroom bodies and exhibit a central body organization reminiscent of certain malacostracan crustaceans.Several hypotheses of brain evolution at the base of the hexapod tree are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. a.boehm@univie.ac.at.

ABSTRACT

Background: In the past decade neuroanatomy has proved to be a valuable source of character systems that provide insights into arthropod relationships. Since the most detailed description of dipluran brain anatomy dates back to Hanström (1940) we re-investigated the brains of Campodea augens and Catajapyx aquilonaris with modern neuroanatomical techniques. The analyses are based on antibody staining and 3D reconstruction of the major neuropils and tracts from semi-thin section series.

Results: Remarkable features of the investigated dipluran brains are a large central body, which is organized in nine columns and three layers, and well developed mushroom bodies with calyces receiving input from spheroidal olfactory glomeruli in the deutocerebrum. Antibody staining against a catalytic subunit of protein kinase A (DC0) was used to further characterize the mushroom bodies. The japygid Catajapyx aquilonaris possesses mushroom bodies which are connected across the midline, a unique condition within hexapods.

Conclusions: Mushroom body and central body structure shows a high correspondence between japygids and campodeids. Some unique features indicate that neuroanatomy further supports the monophyly of Diplura. In a broader phylogenetic context, however, the polarization of brain characters becomes ambiguous. The mushroom bodies and the central body of Diplura in several aspects resemble those of Dicondylia, suggesting homology. In contrast, Archaeognatha completely lack mushroom bodies and exhibit a central body organization reminiscent of certain malacostracan crustaceans. Several hypotheses of brain evolution at the base of the hexapod tree are discussed.

No MeSH data available.


Related in: MedlinePlus

Brain neuropils of Campodea augens. A) Protocerebral bridge (plus sign), parts of mushroom body mb1 (asterisk). Arrows indicate two of the olfactory glomeruli. B) Parasagittal section showing large and irregularly shaped olfactory glomeruli (asterisk) and a less dense region with smaller olfactory glomeruli (plus sign). Arrows indicate third antenno-cerebral tract. Abbreviations: ogl olfactory glomeruli, cb central body, kc Kenyon cells, ms muscle, pi pars intercerebralis. Scale bars: 50 μm.
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Figure 8: Brain neuropils of Campodea augens. A) Protocerebral bridge (plus sign), parts of mushroom body mb1 (asterisk). Arrows indicate two of the olfactory glomeruli. B) Parasagittal section showing large and irregularly shaped olfactory glomeruli (asterisk) and a less dense region with smaller olfactory glomeruli (plus sign). Arrows indicate third antenno-cerebral tract. Abbreviations: ogl olfactory glomeruli, cb central body, kc Kenyon cells, ms muscle, pi pars intercerebralis. Scale bars: 50 μm.

Mentions: The studied species of Japygidae differ from Campodea augens in both number and shape of observed deutocerebral neuropils. In Campodea augens two different types of olfactory glomeruli exist: four to five large, elongated, ventral ones and small spheroidal glomeruli dorsally (Figure8). Neuropils equivalent to the mvdn and lvdn of japygids could not be found in Campodea augens.


Brain anatomy in Diplura (Hexapoda).

Böhm A, Szucsich NU, Pass G - Front. Zool. (2012)

Brain neuropils of Campodea augens. A) Protocerebral bridge (plus sign), parts of mushroom body mb1 (asterisk). Arrows indicate two of the olfactory glomeruli. B) Parasagittal section showing large and irregularly shaped olfactory glomeruli (asterisk) and a less dense region with smaller olfactory glomeruli (plus sign). Arrows indicate third antenno-cerebral tract. Abbreviations: ogl olfactory glomeruli, cb central body, kc Kenyon cells, ms muscle, pi pars intercerebralis. Scale bars: 50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3585824&req=5

Figure 8: Brain neuropils of Campodea augens. A) Protocerebral bridge (plus sign), parts of mushroom body mb1 (asterisk). Arrows indicate two of the olfactory glomeruli. B) Parasagittal section showing large and irregularly shaped olfactory glomeruli (asterisk) and a less dense region with smaller olfactory glomeruli (plus sign). Arrows indicate third antenno-cerebral tract. Abbreviations: ogl olfactory glomeruli, cb central body, kc Kenyon cells, ms muscle, pi pars intercerebralis. Scale bars: 50 μm.
Mentions: The studied species of Japygidae differ from Campodea augens in both number and shape of observed deutocerebral neuropils. In Campodea augens two different types of olfactory glomeruli exist: four to five large, elongated, ventral ones and small spheroidal glomeruli dorsally (Figure8). Neuropils equivalent to the mvdn and lvdn of japygids could not be found in Campodea augens.

Bottom Line: In the past decade neuroanatomy has proved to be a valuable source of character systems that provide insights into arthropod relationships.In contrast, Archaeognatha completely lack mushroom bodies and exhibit a central body organization reminiscent of certain malacostracan crustaceans.Several hypotheses of brain evolution at the base of the hexapod tree are discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Evolutionary Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. a.boehm@univie.ac.at.

ABSTRACT

Background: In the past decade neuroanatomy has proved to be a valuable source of character systems that provide insights into arthropod relationships. Since the most detailed description of dipluran brain anatomy dates back to Hanström (1940) we re-investigated the brains of Campodea augens and Catajapyx aquilonaris with modern neuroanatomical techniques. The analyses are based on antibody staining and 3D reconstruction of the major neuropils and tracts from semi-thin section series.

Results: Remarkable features of the investigated dipluran brains are a large central body, which is organized in nine columns and three layers, and well developed mushroom bodies with calyces receiving input from spheroidal olfactory glomeruli in the deutocerebrum. Antibody staining against a catalytic subunit of protein kinase A (DC0) was used to further characterize the mushroom bodies. The japygid Catajapyx aquilonaris possesses mushroom bodies which are connected across the midline, a unique condition within hexapods.

Conclusions: Mushroom body and central body structure shows a high correspondence between japygids and campodeids. Some unique features indicate that neuroanatomy further supports the monophyly of Diplura. In a broader phylogenetic context, however, the polarization of brain characters becomes ambiguous. The mushroom bodies and the central body of Diplura in several aspects resemble those of Dicondylia, suggesting homology. In contrast, Archaeognatha completely lack mushroom bodies and exhibit a central body organization reminiscent of certain malacostracan crustaceans. Several hypotheses of brain evolution at the base of the hexapod tree are discussed.

No MeSH data available.


Related in: MedlinePlus