Edward Głuchowski

Hypericinoid Pigments In Millericrinids From the Lower Kimmeridgian Of the Holy Cross Mountains (Poland)

Abstract Purple to violet colored millericrinids (Crinoidea) are described from the lower Kimmeridgian of the Małogoszcz quarry, Holy Cross Mountains, Poland. By chemical analysis using high-performance liquid chromatography, ultraviolet/visible spectroscopy, and mass spectrometry, the organic compounds were characterized as a homologous series of hypericinoid pigments ranging from C28H12O8 (fringelite F) to C36H28O8. The results indicate that hypericinoid pigments were more widespread in millericrinids than previously known. The presence of new hypericin derivatives in the fossil crinoids with characteristic alkyl side chains shows that Mesozoic hypericinoid pigments were closely related to recent crinoidal pigments.

Reassessing the improbability of a muscular crinoid stem

Muscular articulations in modern stalked crinoids are only present in the arms. Although it has been suggested that certain coiled-stemmed fossil taxa may have been functionally adapted to utilize muscles, evidence supporting this interpretation is lacking. Here, we use cathodoluminescence and SEM to reveal the skeletal microstructure of the enigmatic coiled-stemmed taxon Ammonicrinus (Flexibilia). Based on the well-established link between skeletal microstructure and the nature of infilling soft tissues in modern echinoderms, we reconstructed the palaeoanatomy of the Middle Devonian ammonicrinids. We show that their median columnals with elongated lateral columnal enclosure extensions (LCEE) have stereom microstructure unexpectedly resembling that in the crinoid muscular arm plates. In particular, large ligamentary facets, that are present on each side of a transverse ridge, are mainly comprised of fine galleried stereom that is indicative of the mutable collagenous tissues. In contrast, fine labyrinthic stereom, commonly associated with muscles, is situated in the periphery on each side of the surface of elongated LCEE. Our findings thus strongly suggest that the muscles may have also been present in the stem of ammonicrinids. These results reassess the previous hypotheses about evolution of muscles in crinoids and provide new insights into the mode of life of Ammonicrinus.