Calcideletrix Mägdefrau, 1937

Wisshak, Max, 2017, Taming an ichnotaxonomical Pandora’s box: revision of dendritic and rosetted microborings (ichnofamily: Dendrinidae), European Journal of Taxonomy 390, pp. 1-99 : 35-36

Calcideletrix Mägdefrau, 1937

Type ichnospecies

Calcideletrix flexuosa Mägdefrau, 1937 , by subsequent designation in Häntzschel (1962).

Original diagnosis

n/a

Emended diagnosis

Dendritic boring system in calcareous skeletal substrates with a series of main axes that give the trace a lobed appearance. Inner branches may anastomose or leave blind-ending branches. Trace closely prostrate and with many contacts to the substrate surface.

Original description

Shrublike ramified cavity system, branches 0.02 to 0.1 mm in diameter, with one or more openings. [Translated from German]

Supplementary description

Based on the analysis of epoxy casts, Plewes (1996) added the following general observations: “To a greater extent than Clionolithes this trace is neither a true rosette nor a network but an intermediate between the two. It always extends along a series of curved or linear axes and so there is no immediate ‘point of origin’ from which all branches proceed. Branches anastomose but not extensively enough to form a true network; within the inner meshwork portion of the trace there are always blind-ending branches. The degree of variability of the branch widths differs between species. This and the density between branches is the main difference between them.”

Remarks

Häntzschel (1975), in the second edition of the trace fossil volume of the Treatise on Invertebrate Paleontology, claimed that it was him in the first edition of the trace fossil volume of the Treatise ( Häntzschel 1962) who has to be regarded as the first author of Calcideletrix , based on the assumption that the original description by Mägdefrau is to be considered a nomen nudum due to a missing designation of a type ichnospecies. However, the designation of a type ichnospecies became a requirement only in 2000 with the 4 th edition of the ICZN, and Mägdefrau’s original description is thus to be regarded as readily valid.

The ichnogenus was established with the two ichnospecies C. flexuosa and C. breviramosa . Based on close morphological similarities, this couple is herein complemented by Dendrina anomala Mägdefrau, 1937 and Polyactina fastigata Radtke, 1991 , extending the morphological range and the size range of Calcideletrix . These four ichnospecies form a morphological series that communicates between the morphological end members of Clionolithes (in particular C. radicans ) and Dictyoporus (in particular D. nodosus ).