Haccourtaster nattestadae, Gale & Jagt, 2025

Gale, Andrew S. & Jagt, John W. M., 2025, New species of the asteroid genus Haccourtaster Jagt, 2000 (Echinodermata, Goniasteridae) from the Upper Cretaceous of Denmark, Sweden and the United Kingdom, Zootaxa 5632 (2), pp. 325-336 : 328-330

Haccourtaster nattestadae sp. nov.

urn:lsid:zoobank.org:act:74BB38E5-CFFA-45EF-9A49-0988DE70E146

Fig. 2L–O

Type material. A group of associated and partly articulated ossicles ( MGUH 34867, holotype) from the Arnager Limestone (lower Coniacian) of the coastal cliff southwest of Arnager (Bornholm, Denmark; compare Kennedy & Christensen 1991; Tröger & Christensen 1991; Christensen & Schulz 1997).

Diagnosis. Medium-sized Haccourtaster (R approximately 8 mm) in which the superomarginals are strongly convex and have a central ridge. Marginals possess evenly spaced granule pits some of which are large and deeply impressed on the median ridges of the superomarginals.

Etymology. Named after local non-professional palaeontologist, Marianne Falbe Nattestad, who collected this and other material of early Coniacian echinoderms from the cliffs near Arnager, Bornholm.

Description. The holotype comprises numerous ossicles, some articulated, in a small piece of chalk. The median superomarginals ( Fig. 2L–O ) are rectangular in abactinal view, and twice as broad as long. The abactinal surface is tumid ( Fig. 2N, O ); in some ossicles this is symmetrical (N), whereas in others the distal margin is sharply depressed (O). The central area of the median superomarginals is sharply defined by a narrow ridge. The central area carries rather evenly spaced granule pits, some of which are deeply impressed ( Fig. 2N ); in one case ( Fig. 2O ) larger pits are present on the lateral-abactinal part of the tumidity. The ultimate superomarginals are triangular with a steep lateral surface which carries evenly sized granule pits ( Fig. 2O ); the abactinal face bears large, widely spaced crater-like pits. The inferomarginals are gently convex and carry evenly sized and evenly spaced granule pits. The median inferomarginal ( Fig. 2M , left) is rectangular in outline, the enlarged penultimate inferomarginal ( Fig. 2M , right) tapers distally. A very small 3 rd inferomarginal is present distal to the enlarged 2 nd ossicles. Intramarginal cavities are present ( Fig. 2L , upper right).

Remarks. Haccourtaster nattestadae sp. nov. differs from its closest relative, H. liticola sp. nov. in the presence of a raised median ridge on the superomarginals which bears deeply impressed, crater-like granule pits. Additionally, the inferomarginals are less broad (compare Fig. 1B with Fig. 2M ) and H. liticola sp. nov. lacks the narrow ridge surrounding the central area on the superomarginals in H. nattestadae sp. nov. The Arnager Limestone was interpreted by Svennevig & Surlyk (2018) to represent a relatively deep chalk environment, dominated by hexactinellid sponges and the other invertebrate fauna is of very low diversity. The only other asteroid described previously from the Arnager Limestone is Metopaster cf. thoracifer ( Wienberg Rasmussen 1950; Svennevig & Surlyk 2018). However, recent collecting from the cliff southwest of Arnager by Ms Nattestad has yielded additional material of what Wienberg Rasmussen (1950) referred to as M. cf. thoracifer , inclusive of (semi-articulated) specimens. These, and comparative material of late Cenomanian–early Turonian M. thoracifer from the Dresden area (eastern Germany) and the Bohemian Cretaceous Basin ( Czech Republic) as described by Geinitz (1871) and Niebuhr & Seibertz (2016) casts doubt over this specific assignment. This matter will be discussed in full in a forthcoming paper.

The Arnager locality is less than 2 km from outcropping Palaeozoic basement ( Svennevig &Surlyk 2018, fig. 1c), so it is possible that the two currently known asteroid taxa, both characteristically nearshore species, were washed into the region from a coastal environment, perhaps a rocky shoreline.

Figures

FIGURE 1. A–F. Haccourtaster liticola sp. nov. A, superomarginal frame in abactinal view, reconstructed from isolated marginals (NHMUK PI EE 18204–18224). B, inferomarginal frame from one side of disc, reconstructed from isolated marginals (NHMUK PI EE 18212–18215). C, abactinal view of median superomarginal (holotype, NHMUK PI EE 18204). D, abactinal view of ultimate superomarginal (paratype, NHMUK PI EE 18205). E, inferomarginal in actinal view (paratype, NHMUK PI EE 18206). F, interradial view of inferomarginal-superomarginal pair (paratypes, NHMUK PI EE 18207, 18208), upper lower Campanian, Ivö Klack, southern Sweden. G–I, Haccourtaster berryensis sp. nov. (NHMUK PI EE 18203). G, abactinal view of superomarginals from one side of disc, reconstructed from associated ossicles. H, reconstructed actinal view of inferomarginals; lower Turonian, Mytiloides mytiloides inoceramid Zone, Berry Cliff, Branscombe (Devon, UK}. J–M. Haccourtaster hrbac Žítt, 2005. J, partial superomarginal frame of juvenile in abactinal view (the original of Žítt, 2005, fig. 4G; NMP O 6369). K, L, superomarginal frame, reconstructed in abactinal (K) and actinal (L) views (NMP O 6362; the original of Žítt, 2005, figs 3, 4). M, interradial profile of superomarginal-inferomarginal pair, the original of Žítt, 2005, fig. 3F (NMP O 6365), uppermost part of Korycany Member, lower Turonian, Velim-Vaclav, Bohemian Basin, Czech Republic. Scale bars equal 1 mm.

FIGURE 2. Species of Haccouraster. A–K, Haccourtaster aemstelensis Jagt, 2000. A, B, isolated median superomarginal, in abactinal (A) and proximal interradial (B) views (NHMM JJ 16614a). C, ultimate superomarginal, in abactinal view (NHMM JJ 16614b). D, E, ultimate inferomarginal, in actinal (D) and abactinal (E) views (NHMM JJ 16614c). F, ultimate superomarginal, in abactinal view (the original of Jagt 2000, pl. 27, fig. 1; holotype, NHMM MB 1044-6/c). G, ultimate superomarginal, in abactinal view (the original of Jagt 2000, pl. 27, fig. 4; paratype, NHMM MB 1044-6/f). H, I, median superomarginal in interradial (H) and actinal (I) views (the original of Jagt 2000, pl. 27, figs 3, 5; paratype, NHMM MB 1044-6/e). J, K, median inferomarginal, in actinal (J) and proximal interradial (K) views (NHMM JJ 16614d), lower upper Campanian (conica/ mucronata Zone, sensu germanico), basal Zeven Wegen Member (Gulpen Formation), former CPL SA quarry, Haccourt (Liège, Belgium). L–O, Haccourtaster nattestadae sp. nov., holotype individual (MGUH 34867), in upper (L) and lower (M) views. N, enlargement of median superomarginal. O, enlargement of superomarginal pair, Arnager Limestone, lower Coniacian, Arnager (Bornholm, Denmark). Scale bars equal 0.5 mm (A–K), 1 mm (N, O) and 5 mm (L, M).