Megalosauridae, Fitzinger, 1843

Allain, Ronan, Vullo, Romain, Rozada, Lee, Anquetin, Jérémy, Bourgeais, Renaud, Goedert, Jean, Lasseron, Maxime, Martin, Jeremy E., Pérez-García, Adán, Fabrègues, Claire Peyre De, Royo-Torres, Rafael, Augier, Dominique & Bailly, Gilles, 2022, Vertebrate paleobiodiversity of the Early Cretaceous (Berriasian) Angeac-Charente Lagerstätte (southwestern France): implications for continental faunal turnover at the J / K boundary, Geodiversitas 44 (25), pp. 683-752 : 718

Megalosauridae ? indet.

( Fig. 28 K-N)

DESCRIPTION

All the large (> 3 cm) blade-like theropod teeth found at Angeac-Charente are tentatively referred to a single taxon, although two tooth morphotypes are present. The first morphotype probably corresponds to mesial teeth ( Fig. 28 K-M), the crown of which are slender and more elongated than in lateral teeth ( Fig. 28N ). The crown height ratio ( Hendrickx et al. 2015a) ranges between 1.91 (ANG M-121) for a lateral tooth and 2.43 for a mesial one (ANG 17-5650). Apart from that, the teeth have the same characters. They are strongly compressed labiolingually. The mesial margin is convex and the distal margin is only slightly concave. Both the distal and mesial carinae are denticulate, but the latter only occurs on the apical half to one third of the crown. The carinae are centrally positioned on both the mesial and distal margins of crowns. There are 12 (ANG 17-5650) to 18 (ANG M-121) denticles per 5 mm along the mesial carinae, and 12 to 15 along the distal carinae at two thirds of the crown height. The denticles are longer mesiodistally than they are basoapically high, and they have a horizontal subrectangular outline. Interdental sulci are present. The enamel is transversely wrinkled and both transverse and marginal undulations are present ( Hendrickx et al. 2015a).

Teeth of large carnivorous dinosaurs, morphologically very close to those of Angeac-Charente, have been reported from the Tithonian of Chassiron and from the Purbeckian of England. The first have been referred with caution to Megalosauridae ( Vullo et al. 2014) , while the latter have been alternately referred to Megalosauridae or Allosauroidea (see Milner 2002). All dental characters described above have been recognized in Megalosauridae ( Hendrickx et al. 2015b) , and we tentatively refer the large dinosaur teeth of Angeac-Charente to this group, but an assignement to another basal tetanuran clade cannot be definitively excluded.

Figures

FIG. 28. — Theropod teeth from Angeac-Charente: A-C, Archaeopterygid tooth (ANG M-09) in lingual (A) and labial (B, C) views; D, Archaeopterygid tooth (ANG M-08) in lingual view; E, F, cf. Nuthetes sp. (ANG M-45) in lingual (E) and distal (F) views; G, cf. Nuthetes sp. (ANG M-61) in lingual view; H, tooth of Tyrannosauroidea indet. (ANG17-5342) in lingual view; I, J, tooth of Tyrannosauroidea indet. (ANG M-73) in lingual (I) and distal (J) views; K, Megalosauridae? indet. (ANG17 R-1748) in lingual view (J); L, M, Megalosauridae? indet. (ANG17-5650) in labial (L) and (M) lingual views; N, Megalosauridae? indet. (ANG M-121) in lingual view. Scale bar: A, B, 1 mm; C-F, 400 µm; G, 5 mm; H-N, 1 cm.