User:GuppyForce/sandbox

GuppyForce/sandbox Temporal range: Late Cretaceous,
Mounted L. lambei skeleton, Royal Ontario Museum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Neornithischia
Clade:	†Ornithopoda
Family:	†Hadrosauridae
Subfamily:	†Lambeosaurinae
Clade:	†Corythosauria
Tribe:	†Lambeosaurini Prieto-Márquez et al., 2013
Type species
†Lambeosaurus lambei Parks, 1923
Genera
†Amurosaurus †Arenysaurus? †Blasisaurus? †Corythosaurus †Hypacrosaurus †Lambeosaurus †Magnapaulia †Nipponosaurus? †Olorotitan †Sahaliyania †Velafrons

Lambeosaurini, previously known as Corythosaurini, is one of four tribes of hadrosaurid ornithopods from the family Lambeosaurinae. It is defined as all lambeosaurines closer to Lambeosaurus lambei than to Parasaurolophus walkeri, Tsintaosaurus spinorhinus, or Aralosaurus tuberiferus, which define the other three tribes. Members of this tribe possess a distinctive protruding cranial crest. Lambeosaurins walked the earth for a period of around 12 million years in the Late Cretaceous, though they were confined to regions of modern day North America and Asia.

History of Classification

The term Corythosaurini was first used by Brett-Surman in 1989, who characterized the taxon via reference to the premaxilary expansion into a hollow helmet-like cranial crest, as well as higher neural spines. The clade was formally defined via phylogenetic analysis by Evans and Reisz in 2007, and this was confirmed by multiple other analyses. In 2011, Sullivan et al. observed that by the rules of priority set by the International Code of Zoological Nomenclature, the name of the tribe ought to be Lambeosaurini due to its containing the defining type genus (Lambeosaurus) of its superior taxon (Lambeosaurinae).

Anatomy

The current articulation of Lambeosaurin anatomy is given by Prieto-Marquez et al., who characterised the tribe by the following traits:

• "Vertical groove on lateral process of premaxilla, located rostral to dorsal process of maxilla and extending ventrally from small opening between premaxillary medial and lateral processes"
• "Vertical groove bounded rostrally by triangular ventral projection of lateral process of the premaxilla"
• "Nasal articulation surface for frontal shaped into rostroventrally-sloping platform"
• "Nasal vestibule folded into S-loop in enclosed premaxillary passages rostral to dorsal process of maxilla"
• "Lateral premaxillary process extending caudodorsal to prefrontal in adults"

Lambeosaurines are classified into Lambeosaurini and Parasaurolophini based on the similarity with these characteristics or those defining Parasaurolophini. Another method of distinguishing the tribes is by the angle of the dural peak. Lambeosaurins possess a dural peak with an angle over 120°, while in parasaurolophins the angle is less than 90°. The anterior semicircular canals are also taller in Parasaurolophins than Lambeosaurins.

Phylogeny

Prieto-Marquez' analysis (2013) also yielded the following cladogram, which shows the relative positions of the four Lambeosaurine tribes.

Lambeosaurinae

Aralosaurini Aralosaurus Canardia Jaxartosaurus Tsintaosaurini Tsintaosaurus Pararhabdodon Parasaurolophini Charonosaurus Parasaurolophus Parasaurolophus cyrtocristatus Parasaurolophus tubicen Parasaurolophus walkeri Lambeosaurini Lambeosaurus Lambeosaurus lambei Lambeosaurus magnicristatus Corythosaurus Corythosaurus casuarius Corythosaurus intermedius "Hypacrosaurus" stebingeri Hypacrosaurus Olorotitan Arenysaurus Blasisaurus Magnapaulia Velafrons Amurosaurus Sahaliyania

Nipponosaurus has also historically been a member of Lambeosaurini, though its position within the tribe is debated. However, a 2018 analysis by Takasaki et al. disputed this, instead placing Nipponosaurus in a clade with Arenysaurus and Blasisaurus as a sister taxa to Lambeosaurini.

An alternative phylogenetic analysis by Xing et al. (2017) produces the following cladogram, which similarly places Arenysaurus outside Lambeosaurini.

Lambeosaurinae

Aralosaurus Tsintaosaurini Tsintaosaurus Pararhabdodon Jaxartosaurus Arenysaurus Parasaurolophini Parasaurolophus cyrtocristatus Parasaurolophus walkeri Charonosaurus Parasaurolophus tubicen Lambeosaurini Olorotitan Amurosaurus Lambeosaurus Lambeosaurus magnicristatus Lambeosaurus lambei Velafrons Hypacrosaurus altispinus Hypacrosaurus stebingeri Corythosaurus Corythosaurus casuarius Corythosaurus intermedius

See also

• Timeline of hadrosaur research
• Lambeosaurinae
• Hadrosauridae
• Ornithopoda
• Parasaurolophini
• Aralosaurini
• Tsintaosaurini