Topic
Malawisaurus
About: Malawisaurus is a research topic. Over the lifetime, 7 publications have been published within this topic receiving 140 citations.
Papers
TL;DR: Phylogenetic analysis confirms that Haestasaurus becklesii is a macronarians, but different data sets place this species either as a non-titanosauriform macronarian, or within a derived clade of titanosaurs that includes Malawisaurus and Saltasauridae.
Abstract: The sauropod dinosaur “Pelorosaurus” becklesii was named in 1852 on the basis of an associated left humerus, ulna, radius and skin impression from the Early Cretaceous (Berriasian-Valanginian) Hastings Beds Group, near Hastings, East Sussex, southeast England, United Kingdom. The taxonomy and nomenclature of this specimen have a complex history, but most recent workers have agreed that “P.” becklesii represents a distinct somphospondylan (or at least a titanosauriform) and is potentially the earliest titanosaur body fossil from Europe or even globally. The Hastings specimen is distinct from the approximately contemporaneous Pelorosaurus conybeari from Tilgate Forest, West Sussex. “P.” becklesii can be diagnosed on the basis of five autapomorphies, such as: a prominent anteriorly directed process projecting from the anteromedial corner of the distal humerus; the proximal end of the radius is widest anteroposteriorly along its lateral margin; and the unique combination of a robust ulna and slender radius. The new generic name Haestasaurus is therefore erected for “P.” becklesii. Three revised and six new fore limb characters (e.g. the presence/absence of condyle-like projections on the posterodistal margin of the radius) are discussed and added to three cladistic data sets for Sauropoda. Phylogenetic analysis confirms that Haestasaurus becklesii is a macronarian, but different data sets place this species either as a non-titanosauriform macronarian, or within a derived clade of titanosaurs that includes Malawisaurus and Saltasauridae. This uncertainty is probably caused by several factors, including the incompleteness of the Haestasaurus holotype and rampant homoplasy in fore limb characters. Haestasaurus most probably represents a basal macronarian that independently acquired the robust ulna, enlarged olecranon, and other states that have previously been regarded as synapomorphies of clades within Titanosauria. There is growing evidence that basal macronarian taxa survived into the Early Cretaceous of Europe and North America.
85 citations
TL;DR: Both comparative morphology and phylogenetic analyses support Mnyamawamtuka as a distinct and distant relative to Rukwatitan bisepultus and Shingopana songwensis from the younger Namba Member of the Galula Formation with these results largely congruent with newly constrained ages for the Mtuka Member (Aptian–Cenomanian) and Namba Members (Campanian).
Abstract: The African terrestrial fossil record has been limited in its contribution to our understanding of both regional and global Cretaceous paleobiogeography, an interval of significant geologic and macroevolutionary change. A common component in Cretaceous African faunas, titanosaurian sauropods diversified into one of the most specious groups of dinosaurs worldwide. Here we describe the new titanosaurian Mnyamawamtuka moyowamkia gen. et sp. nov. from the Mtuka Member of the Galula Formation in southwest Tanzania. The new specimen preserves teeth, elements from all regions of the postcranial axial skeleton, parts of both appendicular girdles, and portions of both limbs including a complete metatarsus. Unique traits of M. moyowamkia include the lack of an interpostzygapophyseal lamina in posterior dorsal vertebrae, pronounced posterolateral expansion of middle caudal centra, and an unusually small sternal plate. Phylogenetic analyses consistently place M. moyowamkia as either a close relative to lithostrotian titanosaurians (e.g., parsimony, uncalibrated Bayesian analyses) or as a lithostrotian and sister taxon to Malawisaurus dixeyi from the nearby Aptian? Dinosaur Beds of Malawi (e.g., tip-dating Bayesian analyses). M. moyowamkia shares a few features with M. dixeyi, including semi-spatulate teeth and a median lamina between the neural canal and interpostzygapophyseal lamina in anterior dorsal vertebrae. Both comparative morphology and phylogenetic analyses support Mnyamawamtuka as a distinct and distant relative to Rukwatitan bisepultus and Shingopana songwensis from the younger Namba Member of the Galula Formation with these results largely congruent with newly constrained ages for the Mtuka Member (Aptian–Cenomanian) and Namba Member (Campanian). Coupled with recent discoveries from the Dahkla Oasis, Egypt (e.g., Mansourasaurus shahinae) and other parts of continental Afro-Arabia, the Tanzania titanosaurians refine perspectives on the development of African terrestrial faunas throughout the Cretaceous—a critical step in understanding non-marine paleobiogeographic patterns of Africa that have remained elusive until the past few years.
55 citations
Journal Article•
19 citations
1 Jan 2006
TL;DR: Evaluation of previous phylogenetic analyses of Titanosauria provides insight into the structure of the character data thus far generated and a starting point for future studies, as well as identifying several stable titanosaur nodes and a core of character data for future analysis.
Abstract: Titanosaurus was named in 1877 for two caudal vertebrae and an isolated femur from Cretaceous rocks of central India. Titanosauridae was coined soon afterwards to encompass numerous taxa, despite their often tenuous associations and limited morphological overlap. Long recognized as wastebasket taxa, “Titanosaurus indicus”, “Titanosauridae” and coordinated rank-taxa are now considered invalid, but the unranked taxon Titanosauria remains valid. Titanosauria currentles includes 40+ species and fi rst appeared during the Middle Jurassic in the form of “wide-gauge” trackways. Titanosaur body fossils do not appear until the Late Jurassic, but they are inferred to have occupied nearly all continental landmasses during the Early Cretaceous. Titanosaurs are the predominant or exclusive sauropods during the Late Cretaceous and represent a key clade for investigation of survivorship patterns and the effects of major tectonic rearrangements on dinosaur evolution. Titanosauria includes several large-bodied species (e.g., Antarctosaurus giganteus, Argyrosaurus superbus, Argentinosaurus huinculensis), as well as species that are diminutive by sauropod standards (e.g., Saltasaurus loricatus, Neuquensaurus australis). Evaluation of previous phylogenetic analyses of Titanosauria provides insight into the structure of the character data thus far generated and a starting point for future studies. Where comparable, analyses agree on several topological points, including (1) the basal position of Andesaurus and Malawisaurus and (2) the derived position of Saltasaurus, Neuquensaurus, Opisthocoelicaudia, and Alamosaurus. This investigation identifi es several stable titanosaur nodes and a core of character data for future analysis. However, many titanosaur species have yet to be included in a phylogenetic analysis. A comprehensive phylogenetic analysis of Titanosauria will require incorporating these taxa as well as new character data. Resolution of titanosaur interrelationships will spur investigation into Mesozoic paleobiogeography, changes in body size distribution through time, wide-gauge limb posture and its biomechanical signifi cance, and patterns in herbivorous apomorphies of Cretaceous dinosaurs. These and other avenues will be explored in future research.
15 citations
1 Jan 2018
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 2 |
| 2018 | 1 |
| 2016 | 1 |
| 2015 | 1 |
| 2006 | 1 |
| 1999 | 1 |