Calcideletrix anomala Wisshak 2017, comb. nov.

Calcideletrix anomala (Mägdefrau, 1937) comb. nov. Fig. 13 Dendrina anomala Mägdefrau, 1937: 55, pl. IV, fig. 5. Dendrina – Radwański 1972 (partim): 257, figs 1–4. Dendrina anomala – (?) Marcinowski 1972: 247, pl. 1, fig. 2 (poor illustration). — (?) Kutscher 1972: 27, fig. 6. — Nestler 1975: 108, fig. 159c (reproduced from Quenstedt 1849). — Hofmann 1996: 67, pl. 5, figs 5–6, pl. 6, figs 1–2, pl. 8, fig. 4. — (?) Košt’ák 2004: 32, fig. 6 (poor illustration). — Rudolph 2014 (partim): 19, fig. 24 (specimen on right). — Breton et al. 2017: 46, fig. 3E. Rosetten-Form B – Hofmann & Vogel 1992: 56, pl. IV, fig. A. Calcidelatrix anomala – Plewes 1996: 189, pl. 33 fig. 8, pl. 35, figs 1–8. Dendrina isp. – (?) Verde 2002: 46, pl. VI, fig. D (poor illustration). Dendrina (Calciteletrix) anomala – Girod & Rösner 2013: 280, fig. 13. Original diagnosis n/a Emended diagnosis Main branches may curve in a sinuous fashion and in small individuals may be devoid of smaller sidebranches along some length of the curve. From these closely prostrate main axes, with usually smooth surface texture, branches divide, may form anastomoses and gradually decrease in diameter to fine pointed ends that connect to the substrate surface. Original description Rosetted cavity system, strongly and regularly branching. Very conspicuous for this species are strongly varying gallery diameters, unlike all other forms described herein. While the main galleries may reach 0.7 mm in diameter, secondary branches may reach only 0.03 mm in diameter. [Translated from German] Supplementary description Based on additional material, including epoxy resin casts, Plewes (1996) added the observations that the main axis is often distinctly curved, branching is polychotomous or dichotomous, the surface texture is smooth and the ends of the many lateral and peripheral branches taper to fine points which intersect with the substrate surface. She provided morphometrical data for the width of the main axes (mean = 96 µm; n = 20; SD = 76.60) and secondary branches (mean = 35 µm; n= 18; SD = 15.28). Hofmann (1996) gave a size range of the trace of 2–6 mm and measured diameters of up to 180 µm for the main axes and 20 to 70 µm for the peripheral tunnels. In addition, he observed rare anastomoses. Type material, locality and horizon The holotype is preserved in a rostrum of an Actinocamax from the Upper Cretaceous of Misburg near Hannover, Germany. It used to be deposited at the collections of the Institut für Geowissenschaften und Geographie, Halle, Germany, where only the original glass negative (MLU.Mäg1937.IV.5) presently remains (Fig. 13A). Consequently, another specimen (Fig. 13 B–C) within the original material of Mägdefrau from the same type horizon and locality, on the same belemnite (MLU.Mäg1937.IV.10) that carries the holotype of Dictyoporus nodosus Mägdefrau, 1937, was selected as the neotype by Plewes (1996). Since the latter designation was not a valid nomenclatural act (unpublished thesis), this neotype designation is hereby formalised. Remarks This ichnospecies was originally established within the ichnogenus Dendrina by Mägdefrau (1937). However, Dendrina is morphologically very distinct and the ichnospecies shows typical characters intermediate between those of Clionolithes and Calcideletrix instead. Plewes (1996) consequently placed D. anomala within Calcideletrix (without discussion or designation as comb. nov. and misspelled as Calcidelatrix). Nevertheless, this synonymisation appears practical and is followed and formalised herein. Calcideletrix anomala is the largest among the suite of ichnospecies of Calcideletrix, and is morphologically closest to the related ichnogenus Clionolithes and in particularly C. radicans. It is clearly distinguished from the latter by the lack of a distinct central node, the common presence of anastomoses of the main galleries in the central area, and by its very gradual decrease in gallery diameter.Published as part of Wisshak, Max, 2017, Taming an ichnotaxonomical Pandora's box: revision of dendritic and rosetted microborings (ichnofamily: Dendrinidae), pp. 1-99 in European Journal of Taxonomy 390 on pages 39-41, DOI: 10.5852/ejt.2017.390, http://zenodo.org/record/383985