File talk:Megalosaurus from Tanzania.jpg

On the provenance and taxonomic identity of the tooth captured on the photo overleaf

Unfortunately there is no catalogue number and no detailed provenance data given in the original image caption on flickr. According to the name of the flickr album in which this image is included, the tooth is/was on display in the NHM in London and may belong to the NHM collections. The online records of the NHM indeed list an isolated tooth of “Megalosaurus ingens” from Tanzania under the collection no. BMNH PV R 6758. This tooth, however, is not from the Mtwara region as suggested for the tooth overleaf by the original image caption on flickr, but from the famous Tendaguru locality in the southeastern part of the Lindi region. The Tendaguru locality is, however, not very far away from the border of the Mtwara region and is situated in the same N-S-trending strip of Post-Karoo deposits. Be that as it may, isolated teeth have a low diagnostic value, and the species Megalosaurus ingens, which is based on an isolated tooth, today is considered a nomen dubium (cf. Carrano et al., 2012, doi:10.1080/14772019.2011.630927). Hence, the tooth overleaf, even though labelled otherwise on display, should not be categorized in the genus category Megalosaurus or one of its subcategories but only in a superordinate category such as Tetanurae or Theropoda. --Gretarsson (talk) 18:17, 17 September 2019 (UTC)

Addendum: Further web research led me to a photograph which shows the tooth in question (easily identifiable through its characteristic cracking pattern) in the exhibition of the NHM [1]. In the explanation next to the tooth there is no mention of a provenance from Tanzania. Also, the genus name Megalosaurus therein is set in quotation marks indicating that it is a questionable or informal assignment (in the sense of “large basal tetanuran theropod”). Another image on flickr shows the same tooth, but in the caption it says “Megalosaurus bucklandii” [2], which is a taxon that was never reported from Africa (suggesting that in the exhibition there is indeed no indication that this specimen comes from Africa). So not only the apodictic assignment of the tooth to Megalosaurus but also its provenance from Tanzania becomes more and more doubtful… --Gretarsson (talk) 21:54, 17 September 2019 (UTC)