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Lende, new therapsid from Permian of Malawi + emydopoid dicynodont mandibles from Tanzania

Ben Creisler

New papers:

Ashley Kruger, Bruce S. Rubidge, Fernando Abdala, Elizabeth Gomani
Chindebvu & Louis L. Jacobs (2015)
Lende chiweta, a new therapsid from Malawi, and its influence on
burnetiamorph phylogeny and biogeography.
Journal of Vertebrate Paleontology (advance online publication)
DOI: 10.1080/02724634.2015.1008698

The Chiweta Beds of Malawi have yielded a diverse late Permian fossil
tetrapod fauna that correlates with that of the Cistecephalus
Assemblage Zone of the South African Karoo Supergroup. Amongst the
fossil therapsids from the Chiweta Beds is the well-preserved skull
and lower jaw of a burnetiamorph, a group of biarmosuchians with
numerous bosses and swellings on the skull. This specimen was reported
in a preliminary paper in 2005 as the first burnetiamorph described
outside of South Africa and Russia. Reanalysis of the morphology and
phylogeny of this specimen places Lende chiweta, gen. et sp. nov., as
the sister taxon to the clade formed by Proburnetia (Paraburnetia
(Pachydectes, Bullacephalus, Burnetia, Niuksenitia)). The greatest
diversity of this basal therapsid group is from South Africa, with six
of nine described genera and a stratigraphic range that extends from
the middle Permian TapinocephalusAssemblage Zone to the upper Permian
Dicynodon Assemblage Zone. Bearing in mind the constraints that govern
fossil preservation, current data suggest that what is now southern
Africa may have been the area of origin for burnetiamorphs. Under this
premise, what is now central Africa represented a corridor that
allowed migration of representatives of the group between the southern
and northern portions of Pangea during the late Permian.


SUPPLEMENTAL DATA—Supplemental materials are available for this
article for free at www.tandfonline.com/UJVP


Kenneth D. Angielczyk & C. Barry Cox (2015)
Distinctive emydopoid dicynodont (Therapsida, Anomodontia) mandibles
from the Permian Ruhuhu and Usili formations (Songea Group), Ruhuhu
Basin, Tanzania.
Journal of Vertebrate Paleontology (advance online publication)

Dicynodont therapsids were discovered in the Permian Usili Formation
(Ruhuhu Basin, Tanzania) in the 1930s and in the Permian Ruhuhu
Formation in the 1960s, with further collections being made in 2007,
2008, and 2012. Here we describe two fragmentary mandibles that
represent a new morphotype of emydopoid dicynodont. One specimen was
collected in the middle fossiliferous horizon of the Ruhuhu Formation,
and the other originated in the overlying Usili Formation. Three
synapomorphies support the placement of these specimens in the
emydopoid subclade Kingoriidae: mandibular fenestra occluded by the
dentary; curved ridge that follows the profile of the symphysis
present on the edge between the anterior and lateral surfaces of the
dentary; and posterior dentary sulcus absent. The specimens may
represent a new dicynodont species, a previously known species for
which mandibular material was unknown, or an intraspecific variant of
Dicynodontoides nowacki. Regardless of which of these options is
correct, the specimens constitute the first taxon with a stratigraphic
range extending from the likely middle Permian middle fossiliferous
horizon of the Ruhuhu Formation into the late Permian Usili Formation.
They also improve our understanding of the middle Ruhuhu tetrapod
fauna, which previously consisted only of Endothiodon tolani.