The fossil record of cranial material belonging to the Titanosauria (sensu Salgado et al. 1997) is very poor. The best specimens are those of Antarctosaurus wichmannianus Huene 1929 (Huene 1929), Saltasaurus loricatus Bonaparte and Powell 1980 (Powell 1992), Rapetosaurus krausei Rogers and Forster 2001 (Rogers and Forster 2001, 2004) and Nemegtosaurus mongoliensis Nowinski 1971 (Nowinski 1971), the later considered closely related to the Titanosauridae (Salgado and Calvo 1997). There are also descriptions of some fragmentary cranial material belonging to Malawisaurus dixeyi (Haughton 1928) (Jacobs et al. 1993), Antarctosaurus septentrionalis Huene and Matley 1933 (Huene and Matley 1933, Chatterjee and Rudra 1996), Titanosaurus indicus Lyedekker 1877 (Chatterjee and Rudra 1996), Ampelosaurus atachis Le Loeuff 1995 (Le Loeuff et al. 1989), and Quaesitosaurus orientalis Kurzanov and Bannikov 1983 (Kurzanov and Bannikov 1983), the later also regarded as closely related to the Titanosauridae (Salgado and Calvo 1997). Besides those there are unnamed titanosaurids from India (Berman and Jain 1982), Rumania (Weishampel et al. 1991), Texas (Tidwell and Carpenter 2003), Uzbekistan (H.D. Sues, pers. com.) and Brazil, the latter composed of a jaw fragment (Henriques et al. 2002). Recently an almost complete titanosaurid skull was briefly mentioned form Patagonia (Calvo et al. 1997, Coria and Salgado 1998) but it still remains undescribed.
Here we report another titanosaurid braincase housed in the paleovertebrate collections of the Museo de Geología y Paleontología de la Universidad Nacional del Comahue (MUCPv). The specimen (MUCPv-334; cast at the Museu Nacional/UFRJ - MN 6913-V) was discovered in December 1999 by the technician Federico Poblete during a fieldtrip to Bajo del Añelo, Neuquén Province, Argentina. It was found 20 km north of the town of Añelo, at the southern margin of the Añelo Basin, in a reddish sandstone layer of the Rio Colorado Subgroup (Ardolino and Franchi 1996), Rio Neuquén Group (Cazau and Uliana 1973, Leanza and Hugo 2001). No detailed stratigraphic column of this site is known. Two articulated titanosaurid tails were collected about 200 meters away from this specimen, but it is not possible at the time being to relate this braincase to one of those caudal vertebral series. More titanosaurid material related to those caudals remains in the field.
This specimen (MUCPv-334) shows some interesting anatomical features and is compared with other sauropod cranial material, increasing thediversity of the braincase morphology within theTitanosauridae. It was briefly reported before (Calvo and Kellner 2004) and is fully described here.