Kukufeldia tilgatensis, MCDONALD, BARRETT & CHAPMAN, 2010

Norman, David B., 2015, On the history, osteology, and systematic position of the Wealden (Hastings group) dinosaur Hypselospinus fittoni (Iguanodontia: Styracosterna), Zoological Journal of the Linnean Society 173 (1), pp. 92-189 : 147

KUKUFELDIA TILGATENSIS MCDONALD, BARRETT & CHAPMAN, 2010 A

This taxon is a potential sympatric contemporary of Hy. fittoni ( Fig. 2 ) and was established upon an isolated, large, and robust dentary with two dentary teeth in place (NHMUK OR28660) that was collected from one of the historically important Whiteman’s Green Quarries near Cuckfield, West Sussex, England ( Fig. 1 ). The quarry area is generally understood to expose lower Wealden strata [Hastings Group (Grinstead Clay Formation) Fig. 2 , GC Fm] of middle−late Valanginian age.

Teeth and jaws

The dentary teeth are broad, shield-shaped, and the primary ridge is distally offset on the lingual surface of the crown; a slightly less prominent secondary ridge subdivides the mesial portion of the crown face into more or less equal sectors. Accessory (tertiary) ridges are either very few or entirely absent (poor preservation). These principal features differ markedly from those described in the dentary crowns of Hy. fittoni . The robust, straight dentary ramus of NHMUK OR28660 differs from the comparatively slender and anteriorly downturned dentary of Hy. fittoni (NHMUK R1831, R1834).

Postcranial skeleton

Unknown.

Taxonomic note

This taxon is currently diagnosed on the basis of a single autapomorphy: an allegedly unique pattern of vascular openings seen on the external surface of the anterior end of the dentary. It should be noted that the pattern of vascular openings on the surface of any dinosaurian dentary can vary amongst individuals referred to the same taxon, and that such variation can also occur between left and right dentaries of the same individual. A single autapomorphy of this quality undermines the status of K. tilgatensis . Additional anatomical evidence used as supplementary support for this new taxon ( McDonald, Barrett & Chapman, 2010a) relied upon the mistaken reference of additional jaw material (NHMUK R1834) to B. dawsoni ( Norman, 2011a) ; this latter material is unambiguously referable to the Valanginian taxon Hy. fittoni ( Norman, 2010, 2011b and herein).

In reply to critical comments concerning the status of Kukufeldia, McDonald (2012b) accepted that the teeth referred to B. dawsoni ( Norman, 2011a, b) resembled those seen in the dentary of Kukufeldia . However, he observed that similar dental morphologies are to be seen in the sympatric taxa Mantellisaurus and Iguanodon and that attribution of the teeth in the jaw of NHMUK OR28860 to B. dawsoni was therefore unsafe. Although the dental resemblances noted by McDonald are true, the two latter species are not Valanginian contemporaries of B. dawsoni (both are substantially younger, having a upper Barremian–Lower Aptian stratigraphical range – Fig. 2 ). There are at present two alternative explanations available for this unsatisfactory situation. Firstly, the jaw collected at Cuckfield might actually pertain either to the Hauterivian or the Weald Clay Formation (Barremian). Inliers of younger beds are known to occur as slivers in the western part of the Hastings Group outcrop area ( Topley, 1875; Batten & Austen, 2011). It is at least possible that the Weald Clay was exposed at Cuckfield at the time the original specimen was collected and that the dentary in question can be referred to I. bernissartensis . In this regard, it is interesting to note that within the Mantell Collection (NHMUK) there are several specimens, notably a sternal bone, pubis, and ischium, all labelled as having been collected from ‘Tilgate Forest’ that resemble the equivalent bones of the Barremian−Lower Aptian aged Mantellisaurus ( Fig. 2 ; D. B. Norman, unpubl. data). Unfortunately, there is no more specific locality information associated with these specimens. If a range extension into the Hauterivian/Barremian is considered inadmissible, the balance of probability appears to favour the assertion that the dentary assigned to K. tilgatensis is from the Grinstead Clay Formation (Valanginian). The only specimen attributed to this latter taxon can be referred to B. dawsoni ; this view is now supported by Andrew McDonald (pers. comm. 5 October 2013).

Figures

Figure 1. The location of the town of Hastings within the county of East Sussex in the UK. Quarries (Q) and location names indicate sites that are known to have yielded Iguanodon-like ornithopod remains (most of which were collected by either Samuel H. Beckles or Charles Dawson). The ambiguity surrounding the location of ‘Hollington Quarry’ is genuine and reflects inconsistencies and vagueness introduced (probably by Dawson) when the documentation of these collections was being assembled in the late 1880s. Abbreviation: IoW, Isle of Wight.

Figure 2. Stratigraphy of the Wealden of southern England. Stratigraphical chart based upon Batten (2011: textfig. 2.1) with the approximate stratigraphical distribution of the principal large-bodied ornithopod taxa indicated using solid vertical bars. Abbreviations: Fm, Formation; GC Fm, Grinstead Clay Formation; Lower Grnsd, Lower Greensand; L.T.W. Sand Fm, Lower Tunbridge Wells Sand Formation; U.T.W. Sand Fm, Upper Tunbridge Wells Sand Formation; B., Barilium; H., Hypselospinus; I., Iguanodon; M., Mantellisaurus.