Details on SVP 2001 Wednesday talks

Hi everyone. I just returned from SVP 2001 in Bozeman and I'm here to provide in depth coverage of the talks I attended and posters I read. I had a great time meeting many of you, as well as some other professionals. The first day was dominated by the sauropod symposium, with the other talks on condylarths, histology and CT scanning. I only attended most of the sauropod symposium and the first half of the condylarth talk. I will discuss the sauropod posters tomorrow, along with the many posters shown on Thursday.

Upchurch and Barrett, 2001. A phylogenetic perspective on sauropod diversity. JVP 21(3) 110A.

This was about estimating change in sauropod diversity using both a simple taxon count, as well as one taking ghost lineages into account. Sauropods diversify in the Middle Jurassic, become most diverse during the Late Jurassic, lower in numbers a bit in the Early Cretaceous and diversify again (though not as much as in the LJ) in the Late Cretaceous. I think there are problems with ghost lineages involving taxa we can't place precisely yet, but my favorite part of the talk was the new cladogram by Upchurch. It used 309 characters and 47 taxa.

|-Vulcanodon
`-+-Kotasaurus
`-+-Shunosaurus
    `-+-+-Barapasaurus
      | `-+-Cetiosaurus
      |   `-Patagosaurus
      `-+-+-Omeisaurus
        | `-Tehuelchisaurus
        `-+-Mamenchisaurus
          `-+-Euhelopus
            `-+-Lourinhasaurus
              `-+-+-+-Nemegtosaurus
                | | `-Quaesitosaurus
                | `-+-Rayososaurus
                |   `-+-+-Amargasaurus
                |     | `-Dicraeosaurus
                |     `-+-Apatosaurus
                |       `-+-Diplodocus
                |         `-Barosaurus
                `-+-+-Bellusaurus
                  | `-+-Atlasaurus
                  |   `-Jobaria
                  `-+-Camarasaurus
                    `-+-Haplocanthosaurus
                      `-Titanosauriformes

I didn't get the chance to write the titanosauriform taxa, but will update once I contact Upchurch. He was very friendly and told me of his upcoming paper sorting out Cetiosaurus. Notable is the lack of any type of Euhelopodidae, a monophyletic Cetiosauridae, an odd basal camarasauromorph clade containing Atlasaurus, Jobaria and Bellusaurus (Bellusauridae has priority here I believe) and diplodocoid nemegtosaurids. I don't think Upchurch included Rapetosaurus, but he said he was very interested in the taxon.

Wilson, 2001. Anatomy of Jobaria tiguidensis and the relationships of Neosauropoda. JVP 21(3) 115A.

Not much new was revealed about Jobaria, but Macronaria and Diplodocoidea were compared. The former is diagnosed by many appendicular characters, the latter by cranial characters. Another cladogram was presented here, this one with 222 characters and 25 taxa.

|-Vulcanodon
`-+-Shunosaurus
`-+-Barapasaurus
    `-+-Patagosaurus
      `-+-+-Omeisaurus
        | `-Mamenchisaurus
        `-+-Jobaria
          `-+-Haplocanthosaurus
            `-+-+-+-Rayososaurus
              | | `-Rebbachisaurus
              | `-+-+-Amargasaurus
              |   | `-Dicraeosaurus
              |   `-+-Apatosaurus
              |     `+-Diplodocus
              |      `-Barosaurus
              `-+-Camarasaurus
                `-+-Brachiosaurus
                  `-+-Euhelopus
                    `-Titanosauria

Unfortunately, I didn't get the titanosaurian section copied in time (these cladograms are up for 20 seconds or so), nor did I talk to Wilson. Now he has a mamenchisaur-omeisaur clade, but Euhelopus is still a titanosauriform.

Curry Rogers, 2001. A new sauropod from Madagascar: Implications for titanosaur lower level phylogeny. JVP 21(3) 43A.

Curry Rogers presented data on Rapetosaurus (unnamed as of publication) and the other Maevarano titanosaur- "taxon B". This species is known from a coracoid (MAD 96-01) and an articulated series of distal caudals (MAD 99-33). The caudals are much lower than Rapetosaurus, while the coracoid is anteroposteriorly shorter with a wide scapular articulation and distal groove (not a coracoid foramen). Yet another cladogram was presented, this one focused on the Camarasauramorpha. 364 characters and 35 taxa were used, but over 200,000 MPT's were generated, making a huge polytomy (which I couldn't read due to the small text anyway). A reduced consensus was performed with taxa scorable for over 15% of the characters (plus taxon B), including 19 taxa.

|-Camarasaurus
`-+-Brachiosaurus
`-+-Euhelopus
    `-+-Phuwiangosaurus
      `-+-Ampelosaurus
        `-+-+-Lirainosaurus
          | `-+-Rocosaurus
          |   `+-Neuquensaurus
          |    `-+-Saltasaurus
          |      `-taxon B
          `-+-+-Nemegtosaurus
            | `-Rapetosaurus
            `-Titanosauridae

I didn't get a chance to see what was in the Titanosauridae. Curry Rogers recommends dividing titanosaurs into three clades- Saltasauridae, Titanosauridae and the "Rapetosaurus clade" (why she didn't just say Nemegtosauridae is confusing).

Sereno and Wilson, 2001. A sauropod tooth battery: Structure and evolution. JVP 21(3) 100A-101A.

Sereno presented this talk, focusing on Nigersaurus. Several skeletons are now known and he showed a slide of the reconstructed mandibles in dorsal view, as well as the skull in lateral view. Much is unknown and the back is based on Rayososaurus, but it looked pretty cool. Large orbit placed posterodorsally, smaller naris not extending past the orbit with a low aof below. Triangular snout with anteriorly placed teeth. Anyone who wants my rough sketch contact me offlist. A diplodocoid cladogram was presented-

A titanosaur has been found in the Elrhaz Formation (with Nigersaurus). It's known from a partial skeleton including skull fragments, cervicals, dorsals, sacrals and a pelvis. In addition, a diplodocoid and titanosaur (the latter very complete, with several individuals) has been found in the Cenomanian of Niger (perhaps the Baharija Formation?).

Wedel, 2001. The evolution of vertebral pneumaticity in the Sauropoda. JVP 21(3) 111A-112A.

This was a great talk that emphasized osteological evidence for pneumatic airsacs in sauropods and concluded that like birds, the presacral column was pneumatized by the cervical airsac while abdominal airsacs pneumatized the sacrals and proximal caudals. He hypothesized both neosauropods and coelurosaurs developed abdominal airsacs (or else ancestrally had them, and just entered the vertebraal bodies in parallel).

Stevens and Parrish, 2001. Biological implications of digital reconstructions of the whole body of sauropod dinosaurs. JVP 21(3) 104A.

Dicraeosaurus has a strongly downward sloping neck if the vertebral articulations are lined up neutrally, while Euhelopus' is slightly downward sloping. Brachiosaurus brancai has a near horizontal neck. Cool, but I'd like to see modern animals tested this way and compared to their actual postures. Platt apparently has a 2001 paper advocating an odd ventrally placed and horizontal scapulocoracoid position in sauropods. I'd like to see that too.

Chure, 2001. A new sauropod with a well preserved skull from the Cedar Mountain Fm. (Cretaceous) of Dinosaur National Monument, UT. JVP 21(3) 40A.

A new specimen from the Poison Strip Member of the Cedar Mountain Formation (Aptian-Albian) preserves a complete skull and first three cervicals. The skull looks like Camarasaurus, but with a diplodocoid naris. The snout is short and dorsally narrow, with a laterally facing subnarial foramen and preantorbital fenestra. The naris is placed like Camarasaurus, but the internarial bar is incomplete dorsally. The quadrate is vertical, the frontals contact the orbits and the jugal is excluded from the ventral skull margin. The mandible has an external mandibular fenestra and possibly a chin. The tooth rows are extensive (3 pmx, 10 mx), the teeth being unexpanded, with convex labial and straight lingual margins and no enamel ornamentation. They are said to be similar to the Astrodon/Pleurocoelus type. The cervicals are elongate with ribs extending two centrum lengths. Other material found in the quarry includes caudals, pectoral and pelvic elements and limb elements (including elongate metacarpals). There is also another different skull in the quarry though, so it is unknown which postcrania are associated with which taxon. The skull was added to Upchurch's 1998 and 1999 analyses and came out as a basal diplodocoid (below nemegtosaurids, rebbachisaurids, dicraeosaurids and diplodocids). They say that with nemegtosaurids coming out as titanosaurs in several recent analyses, these results may change. Neosauropoda incertae sedis I guess. Anyone who wants my sketch of the skull, contact me offlist.

Apesteguia, de Valais, Gonzalez, Gallina and Agnolin, 2001. The tetrapod fauna of "La Buitrera", new locality from Candeleros Formation (Lower Cenomanian) of North Patagonia, Argentina. JVP 21(3) 29A.

This described new remains from the Early Cenomanian Candeleros Member of the Rio Limay Formation. These include two theropod tooth forms- 20 mm abelisaurids (identified by morphology and serration density) and 215 mm carcharodontosaurids (probably Giganotosaurus). Other theropod teeth and phalanges are also known. Sauropods like Andesaurus and Rayososaurus dominate the fauna.

Lamanna, Martinez, Luna, Casal, Dodson and Smith, 2001. Sauropod faunal transition through the Cretaceous Chubut Group of Central Patagonia. JVP 21(3) 71A.

A basal titanosauriform originally described by Martinez (1989) is re-examined. The specimen (including UNPSJB-PV 788 and 988; from the Aptian Matasiete Formation) consists of a scapula, incomplete humerus, ulna and incomplete femur. It's huge, the ulna being 1.18 meters and the scapula 1.73 meters. The scapula has a ventral process caudal to the glenoid, like Brachiosaurus and Paralititan. From the Middle Cenomanian-Coniacian Lower Bajo Barreal Formation comes an almost complete skeleton of Epachthosaurus, lacking only the skull and neck. It has hyposphene-hypantrum articulations in its dorsals and procoelous distal caudals. A phylogenetic analysis places it as a basal titanosaurian. Also from this section of the formation comes the National Geographic titanosaur skull and cervical series, and a rebbachisaurid cervical (identified due to the accessory lamina connecting the spinoprezygopophyseal and postzygodiapophyseal laminae). In the Turonian Upper Bajo Barreal Formation, two specimens were announced. First is fourteen articulated caudals of a titanosaur strongly resembling Aeolosaurus and Gondwanatitan. Second is a rebbachisaurid caudal (UNPSJB-PV 580)

There were several other talks I saw that day too, including

- Russell, Taquet and Wheeler, 2001. Oceanic anoxic events (OAE's), Sauropods and angiosperms in the Saharan tropics. JVP 21(3) 95A.

- Barrett and Upchurch, 2001. Feeding mechanisms and changes in sauropod palaeoecology through time. JVP 21(3) 32A.

- Chiappe, Coria, Dingus, Salgado and Jackson, 2001. Titanosaur eggs and embryos from Auca Mahuevo (Patagonia, Argentina): Implications for sauropod reproductive behavior. JVP 21(3) 40A.

- Bonnan, 2001. Separating size from shape: Using thin-plate splines to evaluate humerus functional morphology in Apatosaurus, Diplodocus, and Camarasaurus. JVP 21(3) 34A-35A.

- Carrano, 2001. The evolution of sauropod locomotion: Morphological diversity of a secondarily quadrupedal radiation. JVP 21(3) 38A.

- Barrick and Russell, 2001. Physiologic implications of ontogenetic variability in oxygen isotope distribution in sauropods. JVP 21(3) 32A.

Two talks were not given-

Apesteguia and Gimenez, 2001. The Late Jurassic-Early Cretaceous worldwide record of basal titanosauriforms and the origin of titanosaurians (Sauropoda): New evidence from the Aptian (Lower Cretaceous) of Chubut Province, Argentina. JVP 21(3) 29A.

Describes a new non-titanosaurid titanosaur from the Aptian Cerro Barcino Formation of Argentina. This specimen has- strongly opisthocoelous dorsals; hyposphene-hypantra; acuminate dorsal pleurocoels; centroparapophyseal laminae; unforked neural spines; postspinal laminae; step shaped articulation in the scapulocoracoid; square coracoid.

Gonzalez Riga and Calvo, 2001. A new genus and species of titanosaurid sauropod from the Upper Cretaceous of Rincon de los Sauces, Neuquen, Argentina. JVP 21(3) 55A.

Describes a new titanosaurid from the Coniacian-Santonian Rio Colorado Formation including cervicals, dorsals, caudals, chevrons, scapula, coracoids, humerus, metacarpals, ilium, pubis and femur. The cervicals are opisthocoelous without cervicals. The dorsals have aliform posteriorly sloping neural spines without saltasaurid characters. The caudals are mostly strongly procoelous, but some are biconcave and biconvex.

Mickey Mortimer