Nododendrina europaea ( Fischer, 1875 ) Wisshak, 2017

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 : 53-56

Nododendrina europaea ( Fischer, 1875) comb. nov.

Fig. 19

Dendrina europaea Fischer, 1875: 530 , pl. XVI, figs 5–6.

Hyellomorpha acuminata Tavernier & Golubic, 1993: 409 , fig. 1A (left), C–D.

Hyellomorpha magna (?) Tavernier & Golubic, 1993: 408, fig. 1A (right), B.

Semidendrina pulchra Bromley et al., 2007: 518 , figs 32.1–32.4.

Dendrina europaea – Fischer 1876: 103 (English translation of Fischer 1875). Without name – (?) Bromley & Surlyk 1973: 362, fig. 9A–B. — Bernard-Dumanois & Delance 1983:

422, pl. 1, figs 1–4 . — Cherchi & Schroeder 1991: 111, figs 1–6 . Gomontia polyrhiza – (?) Boekschoten 1966: 345, fig. 3. — Higazi 1985: 146, pl. 2, fig. 1 . Morfotipo B 5 – Mayoral 1988: 306, pl. 2, fig. 1 , text-fig. 2.1. J-Form C-1 – Glaub 1988: 150, fig. 2C. Dendrina sp. – (?) Powers & Ausich 1990: 235, Fig. 5.1. Globodendrina monile – Plewes et al. 1993 (partim): 83, pl. 1, figs 4–8 (non fig. 1 or pl. 1, figs 1–3 ). —

Plewes 1996: 180, pl. 29, figs 3–8, pl. 40. — Kaminski 2001: 189, fig. 11. — Glaub 2004: 71, fig. 4f. Cliona sp. 1 – Schmidt & Freiwald 1993: 151, fig. 10a. Semidendrina-Form – Glaub 1994: 129, pl. 11, figs 1–4 . Globodendrina – Vogel & Marincovich 2004: 12, fig. 4/2. Globodendrina sp. – Vogel & Glaub 2004: 11, fig. 14. Dendrina incomposita – (?) Košt’ák 2004: 32, fig. 7. Semidendrina -form – Wisshak et al. 2005b: 111, fig. 14B. — Bromley 2005: 906, fig. 9. — Wisshak &

Rüggeberg 2006: 6, fig. 4F–H. — Wisshak 2006 (partim): 91, figs 24, 25F–H. Semidendrina Form – Beuck & Freiwald 2005: 926, fig. 5A–B. Semidendrina pulchra – Wisshak 2008: 215, figs 1A , 2A. — Beuck 2008: 57, 72, figs 2.3.1.6A–B,

2.3.1.14A–B. — Beuck et al. 2010: 467, fig. 6A–B. — Wisshak et al. 2011: 505, fig. 7C. — Taylor

et al. 2013: 234, fig. 13. — Färber et al. 2015: 10 /23, fig. 7G. — Seuss et al. 2015: 509, figs 5F, 6I–J. Semidendrina -form / Semidendrina isp. – (?) Pereira et al. 2009: 335, fig. 5.3.

non? Semidendrina pulchra – Wisshak et al. 2008: 43, fig 9C–E (= Pyrodendrina belua isp. nov.).

Original diagnosis

n/a

Emended diagnosis

From one side of a large and vertically oriented node below the point of entry, a single fan-shaped plexus of branching and anastomosing galleries emerges, connected to the substrate surface by very thin apophyses, increasing in number towards the periphery. Surface texture irregular to spiny.

Original description

If we examine with a lens the outer surface of some coloured shells ( Pecten , for example), small, opaque, irregular, lobulated whitish spots may be observed, these are Dendrina . A rounded orifice terminates a tolerably wide oblique canal, and forms a communication between the exterior and the cavity of the perforating animal. The orifice is single, and resembles the large oscula or efferent apertures of the Clionae, the lobules also are probably in communication with the ambient liquids by exceedingly delicate canals starting from their periphery, a certain number of which open at the surface of the perforated shells. […] In thin plates of shells the perforations of the Dendrinae are seen to be composed of more or less numerous irregularly branched vacuoles, which are inflated here and there, but retain throughout a pretty wide diameter. The youngest are ovoid or lageniform. Although the size of the Dendrinae is variable, it is rare for an individual from the French coast ( Dendrina europaea, Fisch. ) to attain 0.8 mm, generally the maximum diameter is 0.6–0.7 mm. The large osculum measures 0.07 mm, and the lobules vary between 0.06 and 0.08 mm in diameter. […] When a Dendrina is highly magnified, a quantity of minute canals are seen to start from the periphery of the lobules and penetrate the perforated shell in all directions. These canaliculi are cylindrical, rectilinear, slightly dilated near their point of emergence, truncated at their extremities. Sometimes some are a little wider than the others, or slightly curved. Each canaliculus seems to have a distinct origin, there are no anastomoses or bifurcations […]. Their length is from 0.03 to 0.06 mm, and their diameter from 0.0010 to 0.0015 mm. [Translation of original description by Fischer himself (1876)]

Supplementary description

In their detailed investigation of this trace, addressed as the junior synonym Semidendrina pulchra, Bromley et al. (2007) gave the following complementing description, based on SEM analyses of epoxy resin casts: “The dendritic boring comprises two parts: a single, main chamber (c. 50–150 µm wide) that gives issue to a plexus of finer, branching and anastomosing galleries. The main chamber has a single aperture to the surface, 30–60 µm wide. The main chamber is usually connected with the plexus by a single tunnel. This tunnel is either in the size range of the plexus tunnels or up to 50 µm in diameter. Rarely, two or three such tunnels run parallel between the main chamber and the plexus. The shape of the main chamber is variable, ranging from globular to narrow cylindrical, including intermediate forms. Globular chambers commonly have a rather smooth surface whereas narrow cylindrical chambers are commonly heavily ornamented, having an irregular, verrucose surface sculpture with stubby protrusions. The fan-like plexus commonly spreads to cover a half circle around the main chamber, but in well-grown individuals the plexus may exceed a semicircle. The galleries of the plexus display variable diameters ranging from 15–30 µm and vary from almost non-camerate to distinctly swollen as round chambers. Their cross section is usually irregular and not circular as is common for other microborings. The plexus of galleries is generally covered with a variable density of small, hirsute, brush-like apophyses, giving it a finely spinose appearance. These apophyses are most strongly developed at the distal terminations of the galleries, i.e., especially around the perimeter of the boring, and are most densely developed on the surface of the plexus that faces the substrate surface. The plexus is thereby connected to the surface by innumerable slender apophyses having a diameter of <1 µm. The plexus lies up to 10 µm beneath the substrate surface, but this distance diminishes distally. Same galleries show slightly tapering ends. Galleries may fuse together, thereby changing the plexus into a flat, palmate boring. Hair-like extensions on the main chamber, where they occur, are never as long as those on the plexus galleries. In some cases the main chamber surface texture reflects the substrate ultrastructure, taking on a foreign sculpture or xenoglyph.”

Type material, locality and horizon

The hereby designated neotype (= former holotype of junior synonym Semidendrina pulchra ; Fig. 19 C–E) is cast in epoxy from a Lopha sp. bivalve shell from Villers-sur-Mer, France; Argiles à

Lopha gregarea, Oxfordian , Upper Jurassic. Deposited at the Institut für Geowissenschaften, Goethe- Universität, Frankfurt, Germany (Bo 13/159).

Remarks

Since its original description by Fischer (1875) ( Fig. 19 A–B), this very common dendrinid has been addressed by various formal and informal bio- and ichnotaxa, including several junior synonyms, such as Globodendrina monile, Hyellomorpha acuminata, Hyellomorpha magna (? junior synonym or nomen dubium) and Semidendrina pulchra (see list of synonymies above). Even though Fischer based Dendrina europaea on recent material and did not designate type material, this does not preclude the availability for ichnotaxa established prior to 1931, according to ICZN rules, and nor does the incorrect original spelling of the ichnospecies name europaea , which includes a ligature herein corrected to read europaea . Based on its diagnostic characters this trace is herein included in the ichnogenus Nododendrina . Complementing Fischer’s detailed original description and illustration, an ichnospecies diagnosis is provided and the holotype of the now rejected junior synonym Semidendrina pulchra is designated as the fossil neotype for N. europaea .

The ichnotaxon vs biotaxon status of Globodendrina monile Plewes et al., 1993 is problematic since in its original description, both the boring and an agglutinated chimney around the main point of entry, interpreted as agglutinating part of a foraminiferan, was described. Most authors, e.g., Bromley et al. (2007) and Kaminski (2001), consequently consider G. monile as a foraminiferan body fossil in accordance with the original description within the foraminiferan order Astrorhizidae by Plewes et al. (1993).

The development of the plexus on only one side of the main node is a very characteristic feature, which distinguishes N. europaea from the other ichnospecies of Nododendrina . Its average size ranges between that of the usually smaller N. incomposita and the larger N. nodosa .

Figures

Fig. 19. Nododendrina europaea (Fischer, 1875). A–B. Original illustrations of the trace as observed in a transparent shell of the bivalve Pecten opercularis (Linnaeus, 1758) from the Gulf of Gascogne, France (reproduced from Fischer 1875: pl. XVI, figs 5–6; no scale). C–E. SEM overview and close-up of the neotype (= holotype of the junior synonym Semidendrina pulchra Bromley et al., 2007) in an epoxy cast of an Upper Jurassic Lopha shell from Villers-sur-Mer, France. F. SEM of an ontogenetic series as recorded in an epoxy cast of a bivalve shell that was exposed for two years at a depth of 15 m in the Kosterfjord, Sweden (modified from Wisshak 2006).

Fig. 1 (page 7). Morphological characters of dendrinid microborings with respect to overall shape and symmetry of the trace, its vertical profile, openings to the substrate surface, orientation of entrance tunnel (where present), branching pattern and surface texture (in order of decreasing relevance as ichnotaxobase).