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"New" Wilson et al paper on Jainosaurus



Abstract: Early evaluations of sauropod diversity in the Cretaceous of
India recognized three genera,
“Titanosaurus,” Antarctosaurus, and Laplatasaurus, each of which was
thought to have closely
related species on other southern landmasses. Recent systematic work
has challenged the validity
of the genus “Titanosaurus” and the supposed close relationship
between its constituent species,
particularly those from the Cretaceous of South America and
Madagascar. Likewise, Laplatasau-
rus  is currently recognized to be restricted to South America, and
the Indian species is invalid.
Here, we redescribe the anatomy of the Indian sauropod species
Antarctosaurus (now known as
Jainosaurus) septentrionalis with the goal of examining its validity,
constituency, and phyloge-
netic affnity.
The type series of Jainosaurus septentrionalis included a braincase,
skull roof, and many post-
cranial elements that were united on the basis of their large size
relative to the other taxon from
the same quarry, “Titanosaurus indicus”. All postcranial bones were
missing until recently, when
the type series humerus and a cast of the scapula were rediscovered in
the collections of the In-
dian Museum. We evaluate possible associations between type series
elements, bringing to light
circumstantial evidence that helps strengthen the case for grouping
some of them as a single spe-
cies. Both the cranial and some postcranial bones are diagnostic,
allowing referral of additional
materials collected from the same locality and elsewhere in
Indo-Pakistan to the species J. septen-
Currently two genera, Isisaurus and Jainosaurus, are recognized from
the Cretaceous of India.
Unlike most titanosaurs, both Isisaurus and Jainosaurus are known from
diagnostic cranial and
postcranial material recorded from multiple localities. These genera
coexist in central and western
India, and  Isisaurus has been reported recently from western
Pakistan. The affnities of Jaino-
saurus and Isisaurus within Titanosauria are not yet resolved, but a
sister-taxon relationship to one
another can be ruled out. Jainosaurus appears to have close relatives
in Madagascar and South
America based on the data at hand. Thus far, there is no evidence for
an endemic Indian sauropod
fauna during the Late Cretaceous.