Re: Antarctosaurus

[Dinogeorge@aol.com]

In a message dated 11/3/02 1:38:15 PM EST, dino_rampage@hotmail.com writes:

<< Just what the hell is Antarctosaurus?? Is it a titanosaur? A 
late-surviving 
 diplodocimorph? A dicraeosaur? It seems the only thing consistent with all 
 the restorations I have seen is that it is a sauropod. >>

The problem with Antarcosaurus wichmannianus (the type species of 
Antarctosaurus) is that it is based on a syntype series of largely 
disarticulated bones from a bone bed. There's no guarantee that these bones 
all belong to the same genus, let alone the same individual. So far nobody 
has reexamined the syntype series with an eye to nominating one of the bones 
as lectotype. Given its distinctiveness, I'd say the lectotype should be the 
mandible, which to me resembles in many respects the mandible of Nigersaurus, 
though it's nowhere near as derived.

Here is the current Dinosaur Catalogue entry for Antarctosaurus; some of the 
typographically encoded information will be lost in email, but you should 
still glean something useful from it (additions and corrections to entry will 
be greatly appreciated):

Antarctosaurus von Huene, 1929
    Anarctosaurus Janensch, 1935: Misspelling
    Anctartosaurus [Anonymous] 1977: Misspelling
    [in Die Geheimnisse der Urzeit 3, p. 234]
    Antacrtosaurus U. B. Mathur, Pant, Mehra & A. K. Mathur, 1985: Misspelling
    Antactosaurus Arid & Vizotto, 1972: Misspelling
    Antarctosaurus von Huene, 1927 [nomen nudum]: Prepublication name
    Brontosauria > Sauropoda > Eusauropoda > Diplodocimorpha > 
Dicraeosauridae?
?Antarctosaurus brasiliensis Arid & Vizotto, 1972
    Upper Cretaceous > Campanian/Maastrichtian > Bauru Gr. > Adamantina Fm.
    South America > Brazil > Paranà Basin > SÃo Paulo state > Minas Gerais > 
5 km from the SÃo Jose do RÃo Preto-Barretos state highway
    FFCL GP-RD 2â4: Distal two-thirds of left femur, proximal half of right 
humerus, and fragmentary dorsal
    Hypodigm APK: Syntype material only

?Antarctosaurus giganteus von Huene, 1929
    Upper Cretaceous > Turonian/Coniacian > NeuquÃn Gr. > RÃo NeuquÃn Fm. > 
Plottier Mbr.?
    South America > Argentina > Patagonia > NeuquÃn Prov. > 22 km E of 
NeuquÃn City, 15 km N of China Muerta, near confluence of Aguada del CaÃo 
River & RÃo Limay
    MLP 26-316: Associated postcrania, including 2 femora, 2 incomplete 
pubes, extreme distal end of tibia, 6 rib fragments, fragmentary costals and 
2 distal caudals, evidently belonging to a single individual
    Hypodigm APK:0/15: Syntype material only; the femora are still the 
largest known femora of any vertebrate
    Questionably referred to the genus Antarctosaurus in original description

Antarctosaurus jaxartensis Kuhn, 1965
    Misspelling of Antarctosaurus jaxarticus

?Antarctosaurus jaxarticus Riabinin, 1938 [nomen dubium]
    Antarctosaurus jaxartensis Kuhn, 1965: Misspelling
    Upper Cretaceous > Turonian/Santonian > Dabrazinskaya Svita
    Asia > Kazakhstan > Syderinskaya Oblast > Chimkent Dist. > Sary Agach, 
near Syr Darya River
    St. Petersburg Central Geological Research Museum: Femur
    Hypodigm APK: Holotype femur only

Antarctosaurus septentrionalis von Huene & Matley, 1933 [nomen dubium]=
    Antarctosaurus septentrionalis von Huene, 1932 [nomen nudum]: 
Prepublication name
    Antarctosaurus spetentrionalis Glut, 1997: Misspelling
    Antrodemus aptrentronalis Ghevariya & Srikarni, 1994: Misspelling
    Original name of Jainosaurus septentrionalis, possibly a junior 
subjective synonym of Titanosaurus indicus (Jain & Bandyopadhyay, 1997)

Antarctosaurus spetentrionalis Glut, 1997
    Misspelling of Antarctosaurus septentrionalis

Antarctosaurus whichmannianus Bonaparte, 1996
    Misspelling of Antarctosaurus wichmannianus

Antarctosaurus wichmanni von Huene, 1929
    Misspelling of Antarctosaurus wichmannianus

Antarctosaurus wichmannianus von Huene, 1929â
    Antarctosaurus whichmannianus Bonaparte, 1996: MIsspelling
    Antarctosaurus wichmanni von Huene, 1929: Misspelling
    Laplatasaurus wichmannianus von Huene, 1929: Misspelling (referred to 
Laplatasaurus in typographical error)
    Upper Cretaceous > Campanian/Maastrichtian > NeuquÃn Gr. > RÃo Colorado 
Fm. > Bajo de la Carpa Mbr.
    South America > Argentina > Patagonia > RÃo Negro Prov. > RÃo Negro > 
General Roca > Frente a Gral
    MACN 6904: Syntype series of numerous disarticulated bones, including 
incomplete skull w/ braincase, quadrate, quadratojugal, squamosal & mandible 
w/ teeth, 1 cervical vertebra, fragmentary ribs, partial left scapula & 
coracoid, incomplete humerus, distal ulna, proximal & distal radius, 6 
incomplete metacarpals, manual phalanx & ungual, fragmentary ilium, 
incomplete ischium, distal pubis, fragmentary femur, tibia, fragmentary 
fibula, calcaneum, astragalus, 4â5 metatarsals, and pedal phalanges
    Hypodigm APK:15/65: Syntype series, which may be composite (Upchurch, 
1999) and needs restudy and a lectotype chosen (there is no holotype 
specimen, contra Glut, 1997, 2000, who describes all the syntype material as 
the "holotype"; a good candidate for lectotype is the distinctive mandible, 
which is used in some sauropod phylogenetic analyses), along with a partial 
articulated skeleton from S Chubut, Argentina (Bonaparte, 1982) that includes 
6 dorsals, scapula, humerus, radii & ulnae, pubis, incomplete femur, tibia, 
fibula & astragalus, FMNH P13019 right femur & P13020 left tibia (von Huene, 
1929), and numerous isolated elements from various localities in Argentina 
and other South American countries; a large radius from La Candelaria Hills, 
referred to Antarctosaurus sp. by Bonaparte & Bossi, 1967, probably 
represents a distinct genus, as yet unnamed (J. E. Powell, 1979)
    Generic name was first used without description in a faunal list, then 
was formally described and given a type species
    This genus was tentatively removed from its original position in 
"Titanosauridae" and placed into Diplodocidae by Jacobs, Winkler, Downs & 
Gomani (1993), then was reclassified in "Titanosauridae" by Salgado & Calvo, 
1997. The dentary of the type species is perhaps dicraeosaurid (but also 
shows some features of the mandible of Nigersaurus), whereas some of the 
referred specimens, and some of the other species in the genus, may be 
titanosaurian. Though one of the better-known Gondwana sauropods, 
Antarctosaurus requires a thorough systematic revision, and until this is 
completed, reference of species other than the type to this genus will remain 
questionable.