THE MOSASAURS OF ANGOLA

THE MOSASAURS OF ANGOLA
POLCYN, Michael W, Department of Geological Sciences, Southern Methodist University,
Dallas, TX 75275, USA, JACOBS, Louis L., Department of Geological Sciences,
Southern MethodistcUniversity, Dallas, TX, USA, 75275, SCHULP, Anne S.,
Natuurhistorisch Museum Maastricht, Maastricht, The Netherlands, MATEUS,
Octávio, Museu da Lourinhã, Lourinhã, Portugal.
Although occurrences of marine reptiles have been previously reported from Angola, with the
exception of two Turonian taxa, these reports were based largely on isolated teeth. Fieldwork in 2005
and 2006 yielded well-preserved remains of marine reptiles including plesiosaurs, turtles, and
mosasaurs. The mosasaurs discussed here were recovered from two field areas: Turonian sediments at
Iembe along the north coast and Maastrichtian sediments at Bentiaba on the south coast. The
Turonian section near Iembe produced at least two new specimens of Angolasaurus bocagei and one
fragmentary specimen of Tylosaurus iembeensis. One of the Angolasaurus specimens is represented
by a well preserved, complete and articulated skull and partial postcrania, including portions of the
forelimbs and pectoral girdle. The preservation of material from the Bentiaba locality is remarkable
due to the grain support of the entombing sandstone, which preserves fine anatomical details with
little apparent crushing, and in the number of articulated, semi-articulated, and associated skeletons.
Identifications from the field and preliminary preparation show the Bentiaba mosasaur fauna is
represented by at least five genera including Mosasaurus, Prognathodon, Globidens, Plioplatecarpus and Halisaurus. Collectively, these new specimens greatly expand our knowledge of the anatomy and systematics of Angolan mosasaurs.

THE POSSIBLE OCCURRENCE OF ANGOLASAURUS IN THE TURONIAN OF NORTH AND
SOUTH AMERICA
POLCYN, Michael, Department of Geological Sciences, Southern Methodist University,
Dallas, TX, 75275, LINDGREN, Johan, Department of Integrative Biology and
Museum of Paleontology, University of California, 1101 Valley Life Sciences Building,
Berkeley, California 94720-4780, USA, and Department of Geology, GeoBiosphere
Science Centre, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden, and
BELL, Gorden L. Jr., Guadalupe Mountains National Park, Salt Flat, TX 79847,USA.
A partial skull of a mosasaur was collected from the Eagle Ford Formation near Waco Texas in about
1918 and briefly mentioned by Adkins (1924, 1928). The specimen found its way to Sweden through
a donation and was housed in the collections of Lund University until relocated by one of us (GB)
and recently prepared for study. The specimen includes the posterior portion of the skull, preserved to
approximately the anterior terminus of the frontals, the atlas, axis and a portion of the first
hypapohysis-bearing cervical vertebra. It is remarkable in both its Turonian age and the preservation
of the osseous portion of the hyoid apparatus. The dimensions of the frontal and parietal, the path of
the frontoparietal suture, the position of the pineal foreman in the center of the triangular parietal
table, and an enlarged posteroventral process of the parietal meeting the supraoccipital allow tentative
referral of the specimen to the genus Angolasaurus. A second specimen consisting of a partial
premaxilla and jaw fragments containing teeth from the Prionocyclus hyatti zone of the Eagle Ford
Formation south of Dallas, Texas is also likely referable to Angolasaurus. Further, two teeth reported
from the Sergipe Basin in Brazil are virtually indistinguishable from those in the type specimen of
Angolasaurus. Thus Angolasaurus appears to be the only Turonian mosasaur genus represented on
both sides of the Atlantic Ocean. Preservation of the hyoid allows comparison with other squamates
and is consistent with the morphology found in varanoid lizards and markedly different from that of
snakes and thus has bearing on the broader relationships of mosasaurs.

Fonte:
Second Mosasaur Meeting, Sternberg Museum, Hays, Kansas, May 3-6, 2007

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