Brachiosaurus brancai is not Brachiosaurus Michael P. Taylor Palaeobiology Research Group
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Transcript of Brachiosaurus brancai is not Brachiosaurus Michael P. Taylor Palaeobiology Research Group
Brachiosaurus brancaiis not BrachiosaurusMichael P. Taylor
Palaeobiology Research GroupSchool of Earth and Environmental SciencesUniversity of PortsmouthBurnaby Road, Portsmouth PO1 [email protected]
Brachiosaurus altithoraxskeletal reconstruction(Taylor in press)
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
Brachiosaurus at O'Hare Airport, ChicagoBrachiosaurus at O'Hare Airport, Chicago
But we don't have the headOr the neckOr the scapula and anterior dorsalsOr most of the tailOr the lower forelimbs and forefeetOr the lower hindlimbs and hindfeet
But we don't have the headOr the neckOr the scapula and anterior dorsalsOr most of the tailOr the lower forelimbs and forefeetOr the lower hindlimbs and hindfeet
Brachiosaurus brancaiat the Humboldt MuseumBrachiosaurus brancaiat the Humboldt Museum
Brachiosaurus brancaiat the Humboldt MuseumBrachiosaurus brancaiat the Humboldt Museum
Most of what we thinkwe know aboutBrachiosaurus,
we really know aboutBrachiosaurus brancai.
Brachiosaurus brancaiat the Humboldt MuseumBrachiosaurus brancaiat the Humboldt Museum
Most of what we thinkwe know aboutBrachiosaurus,
we really know aboutBrachiosaurus brancai.
But is it Brachiosaurus?
Brachiosaurus altithorax Riggs 1903
Elements from Riggs (1904)
Brachiosaurus brancai Janensch 1914
Elements from Janensch (1922, 1929, 1935-1936, 1950, 1961)
Migeod's Tendaguru brachiosaur (at the BMNH)
Migeod (1931: fig. 1)
The Potter Creek humerus (found 1943)
Jensen (1987: fig 3E)
Photographs by M. Brett-Surman
Subsequent Potter Creek material (1971-1975)
Jensen (1987: fig 3E)
Dry Mesa (“Ultrasauros”) scapulocoracoid
Curtice et al.(1996: fig. 1A)
Referred toB. altithoraxby Paul (1988)
Felch Quarry skull
Modified fromCarpenter and Tidwell(1998: fig. 2)
Carpenter and Tidwell(1998: fig. 1)
Other bits and pieces
BYU 12866 and 12867
OMNH 01138 (Bonnanand Wedel 2004:fig. 1)
Jensen/Jensen rib(Jensen 1987: fig. 6B)
NONE of the referred
Brachiosaurus altithorax
material is convincing.NONE of the referred
Brachiosaurus altithorax
material is convincing.
All we really have to go on is the holotype FMNH P25107
B. brancai compared with Brachiosaurus holotype
Janensch mostly noted general similarity:
“[Brachiosaurus brancai] is so close to the genus Brachiosaurus,so far as a the present state of preparation allows a judgement,that there was no recognisable reason to hold [it] separate fromBrachiosaurus.”
– Janensch (1914:83)
“The dorsal vertebrae of the African Brachiosaurus brancaicorrespond extensively to those of Brachiosaurus altithorax”
– Janensch (1950:72)
“The humerus of the type species of the genus Brachiosaurusaltithorax Riggs (1904) from the Morrison Formation, is in broadterms so similar in outline to Br. brancai that a detailedcomparison is unnecessary.”
– Janensch (1961:187)
Janensch's 13 putative synapomorphies
Janensch's 13 putative synapomorphies
Janensch's 13 putative synapomorphies
Janensch's 13 putative synapomorphies
OKOK
OKOK
Janensch's 13 putative synapomorphies
OKOK
OKOK
Four synapomorphies
Four synapomorphies
The subgenus Brachiosaurus (Giraffatitan)
Erected by Paul (1988) for “Brachiosaurus” brancai
Separation asserted but not demonstrated.
“The caudals, scapula, coracoid, humerus, ilium andfemur of B. altithorax and B. brancai are very similar ...it is in the dorsal column and trunk that the significantdifferences occur.”
Comparisons based in part on the dorsal BYU 9044
And on the scapulocoracoid BYU 9462
The subgenus Brachiosaurus (Giraffatitan)
Erected by Paul (1988) for “Brachiosaurus” brancai
Separation asserted but not demonstrated.
“The caudals, scapula, coracoid, humerus, ilium andfemur of B. altithorax and B. brancai are very similar ...it is in the dorsal column and trunk that the significantdifferences occur.”
Comparisons based in part on the dorsal BYU 9044... which belongs to the diplodocid Supersaurus.
And on the scapulocoracoid BYU 9462
The subgenus Brachiosaurus (Giraffatitan)
Erected by Paul (1988) for “Brachiosaurus” brancai
Separation asserted but not demonstrated.
“The caudals, scapula, coracoid, humerus, ilium andfemur of B. altithorax and B. brancai are very similar ...it is in the dorsal column and trunk that the significantdifferences occur.”
Comparisons based in part on the dorsal BYU 9044... which belongs to the diplodocid Supersaurus.
And on the scapulocoracoid BYU 9462... which is (bad) circular reasoning
Element-by-element comparisons
Mostly based on personal examination.
But Riggs's and Janensch's images arebetter than my photographs.
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Anterior dorsal vertebrae
Posterior dorsal vertebrae
Posterior dorsal vertebrae
Posterior dorsal vertebrae
Dorsal ribs
Dorsal ribs
Dorsal ribs
Dorsal ribs
Dorsal ribs
Variation: serial and individual and asymmetricalVariation: serial and individual and asymmetrical
Sacrum
Sacrum
??
2nd caudal vertebra
2nd caudal vertebra
2nd caudal vertebra
2nd caudal vertebra
2nd caudal vertebra
2nd caudal vertebra
2nd caudal vertebra
2nd caudal vertebra
(Aside: does B. brancai have pneumatic caudals?)
(Aside: does B. brancai have pneumatic caudals?)
(Aside: does B. brancai have pneumatic caudals?)
Coracoid
Coracoid
Coracoid
Coracoid
Coracoid
Humerus
Humerus
GI = 7.53(ratio of length to width) GI = 8.69 (range 7.86–9.19)
Humerus
GI = 7.53(ratio of length to width) GI = 8.69 (range 7.86–9.19)
Humerus
GI = 7.53(ratio of length to width) GI = 8.69 (range 7.86–9.19)
Humerus
GI = 7.53(ratio of length to width) GI = 8.69 (range 7.86–9.19)
Probablyjust damage
Ilium
Ilium
Ilium
Ilium
Ilium
Femur
Femur
Femur
Femur
Summary
All informative elements differ between species: Dorsal vertebrae: 10 differences 2nd Caudal vertebra: 7 differences Coracoid: 4 differences Humerus: 3 differences Ilium: 4 differences Femur: 3 differences
Brachiosaurus altithorax and Brachiosaurus brancaidiffer more than Diplodocus and Barosaurus.
Systematic palaeontology
DINOSAURIA Owen, 1842 SAURISCHIA Seeley, 1888 SAUROPODA Marsh, 1878 NEOSAUROPODA Bonaparte, 1986 MACRONARIA Wilson and Sereno, 1998 TITANOSAURIFORMES Salgado, Coria and Calvo, 1997 BRACHIOSAURIDAE Riggs, 1904 BRACHIOSAURUS Riggs, 1903 BRACHIOSAURUS ALTITHORAX Riggs, 1903 Holotype--FMNH P 25107 GIRAFFATITAN Paul, 1988 GIRAFFATITAN BRANCAI (Janensch, 1914) Lectotype--HMN SII
Systematic palaeontology
DINOSAURIA Owen, 1842 SAURISCHIA Seeley, 1888 SAUROPODA Marsh, 1878 NEOSAUROPODA Bonaparte, 1986 MACRONARIA Wilson and Sereno, 1998 TITANOSAURIFORMES Salgado, Coria and Calvo, 1997 BRACHIOSAURIDAE Riggs, 1904 BRACHIOSAURUS Riggs, 1903 BRACHIOSAURUS ALTITHORAX Riggs, 1903 Holotype--FMNH P 25107 GIRAFFATITAN Paul, 1988 GIRAFFATITAN BRANCAI (Janensch, 1914) Lectotype--HMN SII
Sorry!Sorry!
Phylogenetic analysis
Are Brachiosaurus and Giraffatitan closely related?
I re-scored the matrix of Harris (2006)with separate Brachiosaurus and Giraffatitan OTUs.
(By the way, 13 of the compound Brachiosaurus OTU's331 characters were mis-scored -- 4%.)
Phylogenetic analysis
Brachiosauridae remains monophyletic
Phylogenetic analysis
Brachiosauridae remains monophyletic, but: Only one more step needed to split them up
Phylogenetic analysis
Brachiosauridae remains monophyletic, but: Only one more step needed to split them up What would happen if we added other “brachiosaurs”?
Differences in body proportions
The trunk is about 23% longer in Brachiosaurus
Tail is deeper and probably longer
Humeri may have been laterally deflected
More robust humeri=> may have carried a larger proportion of mass
Giraffatitan reconstruction (Paul 1988)
Brachiosaurus reconstruction (Taylor in press)
Acknowledgements
I thank ... Bill Simpson, David Unwin, Wolf-Dieter Heinrich and Sandra Chapman for access to specimens. Phil Mannion for photographs Gerhard Maier for translations of Janensch. Jerry Harris and Matt Wedel for reviews
And I really am sorry about the name “Giraffatitan”.