Jurapecten dhondtae Gale & Jagt 2021, sp. nov.
Creators: name: Gale, Andy S.
name: Jagt, John W. M.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Asteroidea
Paxillosida
Benthopectinidae
Jurapecten
Jurapecten dhondtae

description: Jurapecten dhondtae sp. nov.
urn:lsid:zoobank.org:act: 3CEF9EA0-184A-4352-87FA-CC5F76FED11A
Fig. 8A–H, J–V
benthopectinid sp. 1 (? spp.) – Jagt 2000: 393, pl. 6 figs 1–4.
Cheiraster? sp. – Blake & Jagt 2005: 190, pl. 5 figs 1–7.
Diagnosis
Jurapecten in which the marginal ossicles possess a coarsely rugose sculpture and the inferomarginals bear a single, large, laterally directed spine base.
Etymology
Named after Annie V. Dhondt (1942–2006), specialist of Cretaceous bivalves and close friend.
Material examined
The inferomarginal illustrated here (Fig. 8F) is the holotype (NHMM JJ 10490a), while the other figured ossicles in lot NHMM JJ 10490 are paratypes. Additional material includes around 50 isolated ossicles (lot NHMM JJ 9591). All material is from the upper Maastrichtian (Maastricht Formation, Emael Member, Lava Horizon) at the CBR-Romontbos Quarry, Eben Emael (Liège, northeast Belgium).
Description
Superomarginals (Fig. 8A–D) block-like, nearly equidimensional, elongating distally. Outer face with sculpture of dense rugosities of similar size and single, crater-rimmed spine base positioned towards abactinal-distal margin. Inferomarginals (Fig. 8E–H, J–K) asymmetrical, proximal margins broader than distal margins; inter-inferomarginal articulation facet close to actinal surface of plate (Fig. 8J), forming short projection. External face of inferomarginal with sculpture of coarse, rounded rugosities and single, large crater-rimmed spine base, positioned centrally, or slightly towards abactinal margin. Ambulacrals (Fig. 8Q–V) with elongated, bar-like ambh, broad, flat ambb, with large, flat surface for dadam and ada3, padam on short wing.Abactinal ridge and inferomarginal articulation absent (Fig. 8V). Adambulacrals (Fig. 8L–M) with concave abactinal face, actinal face with single subambulacral spine base. Enlargement of dadam (Fig. 8P) shows irregularly ridged region, similar to that seen on extant Pectinaster filholi (Perrier, 1885) (Fig. 8I).
Remarks
The marginal ossicles (Fig. 8A–H, J–K) are closely similar to those of Pontaster tenuispinus (von Düben & Koren, 1846) (compare with Fig. 4J–M, O–Q) in shape, sculpture and spine base development,
but the ambulacrals (Fig. 8Q–V) possess elongated heads and lack abactinal ridges and inferomarginal articulation structures, and compare better with those of Jurapecten hessi and J. infrajurensis sp. nov. (see Figs 6J–M, 7M–O).
The partially preserved specimen (NHMM MD 4105), described and illustrated by Blake & Jagt (2005), may be conspecific, but recrystallisation of all ossicle types precludes detailed comparison of the sculpture of infero- and superomarginal ossicles and ambulacral ossicles are too poorly preserved. The type material of J. dhondtae sp. nov., from the middle Emael Member, is ca 200 000 years younger than NHMM MD 4105, from the basal Gronsveld Member (compare Keutgen 2018).
description: Published as part of Gale, Andy S. & Jagt, John W. M., 2021, The fossil record of the family Benthopectinidae (Echinodermata, Asteroidea), a reappraisal, pp. 149-190 in European Journal of Taxonomy 755 on pages 166-168, DOI: 10.5852/ejt.2021.755.1405, http://zenodo.org/record/5032970