Fig. 5. Transmitted light (A1, B1) and hot cathodoluminescence images (A2, B2) of Devonian Phakeloides polonicus gen. et sp. nov. grasping spine A, ZPAL Cg. 2/Ost-Ch.41) and Polygnathus sp. conodont element (B, ZPAL Cg. 2/Ost-C.45) from the upper Famennian, Ostrówka Quarry, Holy Cross Mountains, Poland. A2, weak to moderate red cathodoluminescence of the grasping spine and bright luminescence of some parts of its outermost rim area. B2, very weak yellow-red luminescence of conodont albid tissue and non-luminescent hyaline tissue.

Published as part of Wierzbowski, Hubert & Błażejowski, Błażej, 2023, Chaetognath grasping spines from the Devonian of Poland: their structure and geochemistry, pp. 103-116 in Acta Palaeontologica Polonica 68 (1) on page 110, DOI: 10.4202/app.01012.2022, http://zenodo.org/record/12199254