Taming an ichnotaxonomical Pandora’s box: revision of dendritic and rosetted microborings (ichnofamily: Dendrinidae)
Author
Wisshak, Max
text
European Journal of Taxonomy
2017
2017-12-29
390
1
99
journal article
21907
10.5852/ejt.2017.390
54438cfa-5f3a-4ee3-85c8-00e453a6d641
2118-9773
3839858
4D1D1CA3-8345-4BA3-9C7C-5EBDD40752CE
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.
Fig. 25.
Pyrodendrina
belua
isp. nov.
A
. SEM planar view of holotype, surrounded by a carpet of other microborings in an epoxy cast prepared from a bivalve shell sampled from the Middle Pennsylvanian Buckhorn Asphalt Lagerstätte in Oklahoma, USA.
B–C
. Lateral views of holotype illustrating vertically oriented galleries, parts of which bearing perpendicular side braches.
D
. Detail of terminal widening and spiny ornamentation.
E
. Detail of slender prostrate galleries with terminal swellings and typical branching pattern; an anastomosis is developed at the lower right.
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.