Ichnoreticulina elegans (Radtke, 1991)

Description: Ichnoreticulina elegans penetrates the substrate as approximately 3-μm-thin galleries, which build a substrate-parallel network. The cross section is oval (i.e., onlyslightly flattened). Galleries extend for several tens to more than 100 μm in length on the casts surface.

Remarks Producer of the trace is Ostreobium quekettii Bornet and Flahault,1889, a siphonal alga (e.g., Kornmannand Sahling 1980). This alga is very common in the deep euphotic zone but, as only representative of chlorophytes, it is found down in dysphotic zone and therefore, it is used as a key bathymetric species (Glaub 1994 ).

2004

; Wisshak et al.

2008

)

Diagnosis – (Translation from the original German; after Radtke, 1991, p. 68.) “Thin linear tunnels parallel to the substrate’s surface having multiply dichotomous branches. Swelling occurs at or near the branching nodes.”
Description – Reticulina is characterized by multibranched, 2-4 branches per canal, linear canals that are parallel to the substrate surface. These canals form a mesh-like network. Vertical branching is sporadic and swelling occurs at a majority of the branching nodes.

Description. In contrast to many fossil and Recent settings, this ichnospecies was encountered only very sporadically in the present material. The ichnospecies is characterised by substrate-parallel branched networks of thin (~3 µm) galleries with flattened-oval cross section (Fig. 8E) and occasional zig-zag course of second order galleries. The colonies are oriented closely parallel to the substrate surface and are thus often obscured by other traces (Fig. 8E).