Pyritonema villosa Wisshak 2017, isp. nov.

Pyrodendrina villosa isp. nov.

urn:lsid:zoobank.org:act: 1365F057-8115-4FF7-9F0D-48E5C896CECA

Fig. 26

Morfotipo B 4 – (?) Mayoral 1988: 306; pl. I, figs 6–7.

Sponge form II – Wisshak et al. 2005a: 991, fig. 7B.

Semidendrina Form – Wisshak et al. 2005a: 993, fig. 9.

Foraminiferan trace – Försterra et al. 2005: 957, fig. 9D–H.

non-camerate radiating form – Bromley 2005: 908, fig. 10.

Hirsute camerate form – (?) Bromley 2005: 908, fig. 11.

Semidendrina -form – Wisshak 2006 (partim): 91, fig. 29C–D.

Microsponge-form 2 – Wisshak 2006: 84, fig. 28D.

Foraminiferan Form – Beuck et al. 2010 (partim): 467, fig. 8C–D.

Clionolithes isp. – (?) Pokorný & Štofik 2016: fig. 11L.

Diagnosis

Central node of elongate to irregular shape located at shell surface as open channels, with branched and tapered galleries radiating from it, as well as shorter vertical tunnels penetrating deeper into the substrate. Gallery terminations blunt to tapered, ornamented with long, hairy protrusions.

Etymology

From the Latin ‘villosus’, villous, a reflection of the irregular, furry ornamentation of this trace.

Type material, locality and horizon

Holotype (Fig. 26 A–D) and a number of additional specimens cast in epoxy from a Lophelia pertusa coral skeleton from the Lindos Bay Formation, Middle Pleistocene, found at isolated hill one km SW of Lardos, Rhodes, Greece. For further details concerning the type locality and its ichnological record, see Titschack et al. (2013) and Wisshak (2008). Deposited in the trace fossil collection of the Senckenberg Institute in Frankfurt, Germany (SMF XXX 866).

Description

The irregularly-shaped and branched central cavity of this large Pyrodendrina ichnospecies is developed as system of open channels at the substrate surface (Fig. 26A, E–F), while side branches radiating from it may run as tunnels closely parallel to and below the surface. The true extent of the open channels may be uncertain due to collapse of the thin roof of the trace, particularly in taphonomically advanced stages. Anastomoses are rare. The overall outline of the trace may be elongate (Fig. 26G) to more rosetted (Fig. 26 H–I), and the number of lateral branches varies strongly. The cross section of the side branches varies from circular to horizontal flattened or vertically condensed. Gallery terminations are either blunt or tapered. Along the entire central node and the radiating branches, vertically oriented projections may reach deeper into the substrate and taper (Fig. 26D, G). A multitude of spiny protrusions extend deeper into the substrate or form a horizontal extension or contact to the substrate surface in the case of prostrate cavities (Fig. 26C, I). Apart from the hairy ornament, the surface texture is irregularly bulged and in some cases weakly cuspate.

Trace diameters measured from epoxy casts of 18 specimens from various localities (see below) yield a maximum length of the trace ranging from 1107 to 3844 µm (mean = 2461 ± 759 µm; measured without peripheral spiny protrusions), and a maximum width of 1005 to 2389 µm (mean = 1601 ± 478 µm). Radiating galleries have diameters of 35 to 245 µm (mean = 99 ± 37 µm; n = 160). The maximum length of the spiny protrusions ranges from 83 to 392 µm (mean = 240 ± 111 µm).

Remarks

Additional material was investigated from Miocene bivalves from SE Australia, Pleistocene cold water corals sampled in Messina, Sicily, Recent cold water coral reef sites such as Stjernsund and Sula Reef (Norway), Säcken Reef (Sweden), reefs off Santa Maria di Leuca (Italy), and from a subfossil arctic bivalve shell sampled off SW Svalbard.

This large ichnospecies of Pyrodendrina is distinguished from other members of the ichnogenus by its development of open channels and by the particularly pronounced spiny surface texture. It has the shortest vertical galleries in relation to the dimension of the horizontal cavity.