Gigantosaurus robustus, Fraas, 1908

Mannion, Philip D., Upchurch, Paul, Schwarz, Daniela & Wings, Oliver, 2019, Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution, Zoological Journal of the Linnean Society 185, pp. 784-909 : 822

Gigantosaurus robustus : Janensch, 1929a

Etymology: The genus name honours the Wamwera, the most populous tribe in the Lindi District, which includes the area of Tendaguru Hill, and caudia is derived from the Greek for tail, in reference to the elements comprising the holotype. The species name is in recognition of the efforts of Mohammadi Keranje, who supervised the excavation of the holotypic individual ( Maier, 2003).

Holotype: MB.R.2091.1–30, 3817.1 and 3817.2 (G1– 30) – a series of 30 articulated caudal vertebrae, two anterior caudal neural spines and two incomplete chevrons.

Type locality and horizon: Quarry G, approximately 600 m south of Tendaguru Hill, Lindi District, south-eastern Tanzania ( Fig. 1); Upper Dinosaur Member (Upper Saurian Bed), Tendaguru Formation; Tithonian, Late Jurassic ( Janensch, 1929a; Bonaparte et al., 2000; Aberhan et al., 2002; Remes, 2007; Bussert et al., 2009).

Referred material: MB.R.2094 (Oa12) – an isolated anterior caudal vertebra; Obolello, Quarry Oa, approximately 15 km south-west of Tendaguru Hill, Lindi District, south-eastern Tanzania ( Fig. 1); Upper Dinosaur Member (Upper Saurian Bed), Tendaguru Formation; Tithonian, Late Jurassic ( Janensch, 1925b, 1929a; Bonaparte et al., 2000; Aberhan et al., 2002; Bussert et al., 2009). Janensch (1929a) mentioned the existence of more than one anterior caudal vertebra from this locality, but only MB.R.2094 remains in the MfN collections ( Bonaparte et al., 2000).

Diagnosis: Wamweracaudia can be diagnosed by four autapomorphies (marked with an asterisk), as well as two local autapomorphies: (1) anteriormost caudal ribs curve strongly anterolaterally; (2) dorsal surface of centrum posteriorly excavated in anterior– middle caudal vertebrae*; (3) paired tubercles present on lateral surface of prezygapophysis and on dorsal surface of caudal rib (situated an approximately equal distance between the prezygapophysis and the lateral tip of the caudal rib) in anterior caudal vertebrae; (4) rugosity along the dorsal third of the lateral surface of anterior caudal neural spines, separated from the postspinal rugosity by a vertical groove*; (5) ventral surface of middle–posterior caudal centra strongly constricted transversely to form a ridge rather than a distinct, transversely wide surface*; (6) anteroposteriorly elongate ridge on lateral surface of middle–posterior caudal neural spines, just above the level of the postzygapophyses*.

Additional comments: These caudal vertebrae were originally referred to Janenschia robusta by Janensch (1929a), although no basis was given for this attribution. We can only assume that this referral was based on comparisons with the now lost caudal vertebrae from Quarry P. However, it is impossible to discern the morphology of these vertebrae based on the surviving field map of Janensch ( Fig. 10) and, as illustrated, they appear most likely to represent middle–posterior caudal centra, making the recognition of shared features difficult. As such, there is currently no basis for referring them to Janenschia (see also: ‘Discussion – Oversplitting of Tendaguru sauropods?’).

DESCRIPTION AND COMPARISONS OF HOLOTYPE MATERIAL OF WAMWERACAUDIA KERANJEI GEN. ET SP. NOV.