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Development Genes and Evolution

, Volume 211, Issue 2, pp 89–95 | Cite as

Pondering the procephalon: the segmental origin of the labrum

Opinion Paper

Abstract.

With accumulating evidence for the appendicular nature of the labrum, the question of its actual segmental origin remains. Two existing insect head segmentation models, the linear and S-models, are reviewed, and a new model introduced. The L-/Bent-Y model proposes that the labrum is a fusion of the appendage endites of the intercalary segment and that the stomodeum is tightly integrated into this segment. This model appears to explain a wider variety of insect head segmentation phenomena. Embryological, histological, neurological and molecular evidence supporting the new model is reviewed.

Insect head Intercalary Labrum Stomodeum Segmentation 

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Copyright information

© Springer-Verlag 2001

Authors and Affiliations

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    • 1
  •  
    • 2
  •  
    • 1
  1. 1.USDA, ARS, Grain Marketing and Production Research Center, Manhattan, KS 66502, USA
  2. 2.Division of Biology, Ackert Hall, Kansas State University, Manhattan, KS 66506, USA

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