Feeding postures as indicators of mutable collagenous tissue in extinct echinoderms.

Area of Science:

• Paleontology
• Zoology
• Evolutionary Biology

Background:

• Echinoderms possess unique traits like pentameral symmetry and Mutable Collagenous Tissue (MCT).
• Phylogenetic analysis of echinoderms is complicated by the difficulty in tracing the geologic history of these traits.
• The presence and function of MCT in extinct echinoderm classes remain largely unknown.

Purpose of the Study:

• To investigate the presence of Mutable Collagenous Tissue (MCT) in the extinct echinoderm class Blastoidea.
• To analyze fossilized blastoid structures for evidence of MCT's unique properties.
• To enhance understanding of echinoderm evolution and the functional morphology of extinct species.

Main Methods:

• Analysis of rare Devonian blastoid specimens from Germany.
• Microscopic examination of preserved brachioles for structural integrity and configuration.
• Comparative analysis of brachioles within individual specimens to infer tissue state transitions.

Main Results:

• Evidence of Mutable Collagenous Tissue (MCT) was identified in the brachioles of extinct blastoids.
• Fossilized brachioles were preserved in both rigid and compliant states, suggesting dynamic tissue properties.
• Specimens displayed varying brachiolar configurations, potentially indicating nervous control over MCT in individual brachioles.
• Observed transitions from rigid to compliant states in brachioles suggest rapid burial and preservation during dynamic environmental conditions.

Conclusions:

• Mutable Collagenous Tissue (MCT) was present in the extinct Blastoidea, expanding its known occurrence in echinoderms.
• The dynamic nature of MCT in blastoids suggests sophisticated control over feeding structures.
• These findings provide crucial insights into the evolutionary history and functional morphology of early echinoderms.