Upload
autumn-ferguson
View
221
Download
2
Tags:
Embed Size (px)
Citation preview
Sweet seventy-five and
never been kissed.
The Natural
History Museum's
Tendaguru brachiosaur
Mike Taylor
University of Portsmouth
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
This is where we’re headed in the next twenty minutes:
Historical background German expeditions British expeditions
The “M23 sauropod” of Migeod and Parrington Material Migeod’s account Comparison with Brachiosaurus specimens
Overview
Historical background
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
From 1907-1914, German expeditions led by Werner Janensch excavated dinosaur bones from Tendaguru Hill in
what was then German East Africa
(now Tanzania).
Map modified from Maier 2003
Historical background
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
The expeditions
used hundreds
of native
labourers
and recovered
many
spectacular
specimens.
Photo modified
from Maier 2003
Historical background
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
The best-known result of the German Tendaguru expeditions
is the Brachiosaurus brancai
mount at the Humboldt Museum in
Berlin.
This includes elements of the
holotype HMN SII (although the
mounted skull and vertebrae are
plaster models).
Historical background
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
That's Diplodocus down
there, looking like a toy.
Historical background
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
German East Africa changed hands in the Great War (1914-1918), becoming the British territory of Tanganyika.
The British Museum (Natural History), aware of the German
material, wanted to recover its own exhibit-quality specimens.
From 1924-1930, the BMNH sent a series of expeditions led first
by Cutler and Leakey, and then by Migeod and Parrington. They
went with the express intention of recovering a specimen for
display.
This talk is about what they found.
The “M23 sauropod”
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
In the 1930 field season, Migeod and Parrington opened their 23rd quarry, named “M23”. This proved to contain the greater part of a sauropod skeleton, which was excavated and shipped to London. It is widely assumed to be Brachiosaurus brancai.
This specimen has often been incorrectly referred to as
BMNH M23 (e.g. Paul 1988), but is correctly BMNH R 5937.
The “M23 sauropod”
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
In the 1930 field season, Migeod and Parrington opened their 23rd quarry, named “M23”. This proved to contain the greater part of a sauropod skeleton, which was excavated and shipped to London. It is widely assumed to be Brachiosaurus brancai.
This specimen has often been incorrectly referred to as
BMNH M23 (e.g. Paul 1988), but is correctly BMNH R 5937.
I call it “The Archbishop”.
Material
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
The material identified and excavated by Migeod includes:
Three teeth (doubtfully associated)
A sequence of at least 21 articulated presacral vertebrae
(probably C4-D11, with maybe D12 and even D13)
Sacrum, consisting of five vertebrae
A sequence of nine articulated caudal vertebrae
Cervical ribs and “ossified tendons” (probably the same)
Dorsal ribs
Left scapulocoracoid
Both humeri
Ilium, broken ischium and partial pubis
Broken femur, fragments of another, and a calcaneum
Material
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
The material identified and excavated by Migeod includes:
Three teeth (doubtfully associated)
A sequence of at least 21 articulated presacral vertebrae
(probably C4-D11, with maybe D12 and even D13)
Sacrum, consisting of five vertebrae
A sequence of nine articulated caudal vertebrae
Cervical ribs and “ossified tendons” (probably the same)
Dorsal ribs
Left scapulocoracoid
Both humeri
Ilium, broken ischium and partial pubis
Broken femur, fragments of another, and a calcaneum
Awesome!Awesome!
Material
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
This actually compares
pretty well with HMN SII
Skeletal reconstruction modified
from Wedel 2000.
Pink bones were excavated in 1930.
Prepared material
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Skeletal reconstruction modified
from Wedel 2000.
Pink bones were excavated in 1930.
Red bones have been prepared.
Migeod's 1931 account
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
The only published paper on BMNH R 5937 is Migeod's (1931) account of the 1930 field season.
This says many surprising things, such as:
“The anterior dorsal vertebrae apparently had their neural
spines in two parts, which led me at first to the opinion
that this dinosaur was a Dicraeosaurus. This view proved
on further excavation to be untenable, and indeed the
bifurcate spines were similar to neither species of
Dicraeosaurus found at Tendaguru by the Germans”
But how far can we trust Migeod?
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
“Parrington soon discovered that Migeod's pretensions concealed a profound ignorance of many subjects.”
-- Charig's obituary of Parrington.
“The few good bones he collected would not constitute a single limb
and but a few feet of backbone. Indeed, much of East Africa was
enclosed in plaster with the mistaken impression that bone was
contained within.”
-- W. E. Swinton, letter to John McIntosh, October 1962.
“A charlatan”
-- Parrington's description of Migeod.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
... and my favourite ...
“Migeod does not have the slightest notion of palaeontology.”
-- Friedrich von Huene, letter to Janensch, March 1927.
But how far can we trust Migeod?
So what can we trust?
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
The quarry map is
very useful.
While the association of
the scapula and humeri
are doubtful,
it shows that the
vertebral sequence
is real.
Neck/torso proportions
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Vertebra Length (cm) SourceC9 99 MigeodC10 104 MigeodC11 94 InterpolationC12 84 MigeodC13 61 MigeodD1 36 MigeodD2 28 MigeodD3 27 MigeodD4 27 InterpolationD5 28 MigeodD6 29 InterpolationD7 31 InterpolationD8 32 Pers. obs.D9 34 Pers. obs.D10 29 InterpolationD11 23 MigeodD12 23 Interpolation
Total length of proximal neck (C9-C13): 442cm
Total length of torso
(D1-D12): 347cm
Proximal neck/torso = 1.27
In HMN SII, this ratio is 1.11
So the Archbishop's neck is
proportionally 14% longer.
(probably more, in fact.)
So what is the Archbishop?
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
General shape of vertebrae is definitely Brachiosaurus-like.
Proportionally longer neck suggests something unusual.
Migeod's “bifurcated neural spines” are intriguing.
Migeod also described “great wings” in D1-D4.
Proportions of appendicular skeleton are all wrong, e.g.:Archbishop humerus/C9-C13 = 146/442 = 33%HMN SII humerus/C9-C13 = 213/466 = 48%So Archbishop humerus is only 70% expected length!
(IF we can trust Migeod's measurement and association.)
This suggests that it might not be Boring Old Brachiosaurus.
It's time to look at the material!
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Four cervicals (3 visible)
Two good dorsals
Two dorsal centra
Long-bone fragment
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Far too much material for 20 minutes!
For the rest of this talk, I am
just going to look at dorsals A+B
They are very well preserved,
especially on the right side.
Some parts are reconstructed in
plaster, but this is mostly easy
to spot.
The lateral processes are
broken on both sides.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Which dorsals are they?
Migeod 1931 says:
“All the dorsal centra [...] were with one exception adhering
very firmly to each other, especially the more anterior ones,
so that some of them could only be separated by cutting […]
The exception was a break between D6 and D7.”
So A+B are Migeod's D7 and D8.
However, these vertebrae of Migeod's usage are in fact D8 and D9,
as an extra dorsal was found beneath his “D6” after the numbers
were assigned.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Comparison with Brachiosaurus type specimens
Posterior dorsals of each specimen.
Archbishop (BMNH R 5937)
D8 and D9
Brachiosaurus altithorax
(FMNH P 25107) D8
Brachiosaurus brancai
(HMN SII) D7
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Comparison with Brachiosaurus type specimens
Posterior dorsals of each specimen.
Archbishop (BMNH R 5937)
D8 and D9
Brachiosaurus altithorax
(FMNH P 25107) D8
Brachiosaurus brancai
(HMN SII) D7
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Serial variation among B. brancai dorsals
D11 and D10 D9 (modified from
Janensch 1950)
D4D7
The preserved dorsal vertebrae of the Brachiosaurus brancai holotype
HMN SII are very different. This does not make it is easy to compare
the Archbishop dorsals with “Brachiosaurus brancai”.
Dorsals A+B have five charactersnot seen in classic Brachiosaurus:
Tips of neural spines subcircularand anteroposteriorly long.
Reduced rugosity on posteriorface of spine.
Lateral ridges on pedicels. Neural spine tall relative to
centrum length. Cotyle taller than wide.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Anomalous characters
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Archbishop
(dorsal view,
at right)
Spine caps are
relatively large,
and irregularly
shaped
(subcircular).
1. Tips of neural spines subcircular and largeBrachiosaurus altithorax
(dorsal view, at right)
Brachiosaurus brancai
(left posterolateral, below)
Spine caps are roughly
semicircular with the flat
face at the back.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Dorsals A+B, showing total anteroposterior length of
both spine-caps (red) and centra (blue).
Total spine-cap length is 62% total centrum length.
In Brachiosaurus altithorax (left), it is 40%
In Brachiosaurus brancai (right), it is 35%
1. Tips of neural spines subcircular and large
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
2. Reduced rugosity on posterior face of spine
The Archbishop has a
T-shaped rugosity composed
of semicircle like that of
B. brancai together with a
broad, shallow, rugose
postspinal lamina.
Brachiosaurus altithorax
has distinctive triangular rugosities on
both faces of the neural spine.
Brachiosaurus brancai
has a semicircular
rugosity, with the flat part
directed ventrally.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
2. Reduced rugosity on posterior face of spine
The Archbishop has a
T-shaped rugosity composed
of semicircle like that of
B. brancai together with a
broad, shallow, rugose
postspinal lamina.
Brachiosaurus altithorax
has distinctive triangular rugosities on
both faces of the neural spine.
Brachiosaurus brancai
has a semicircular
rugosity, with the flat part
directed ventrally.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
3. Longitudinal ridges on pedicels of neural arch
Both dorsals have prominent ridges running along the neural arches.
In posterior view, the neural arch appears “waisted” below the ridges.
I have not seen this morphology in any other sauropod.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
4. Neural spine tall relative to centrum length
D8+9 of Brachiosaurus altithorax (left), B. brancai (middle),
and Archbishop (right). Centra scaled to similar lengths.
Archbishop verts are 30% taller than B. altithorax,
20% taller than B. brancai.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
5. Cotyle taller than wide
Archbishop cotyle (above)
height/width = 1.16
No crushing is apparent.
Brachiosaurus brancai cotyles (left)
Upper: SII:D7 -- height/width = 0.62
Lower: AR1 -- height/width = 0.60
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Conclusions
BMNH R 5937 includes some very well preserved material (despite Swinton's dismissal of the specimen).
The skeleton is comparable to HMN SII in completeness.
Much of the excavated material remains unprepared.
Migeod's interpretations of the material are unreliable.
The specimen is a brachiosaurid sauropod.
Serial variation in Brachiosaurus brancai makes it difficult to interpret
the NHM specimen.
The Archbishop's neck is proportionally longer than in B. brancai.
BMNH R 5937 may represent a new taxon, based on five unique
characters of the well-preserved pair of dorsals.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Acknowledgements
Thanks are due to …
Dave Martill for his supervision.
Sandra Chapman and Paul Barrett (Natural History Museum),
Dave Unwin and Wolf-Dieter Heinrich (Humboldt Musuem fur
Naturkunde) and Bill Simpson (Field Museum of Natural
History) for access to specimens.
Matt Wedel for making me realise I could do this.
This work has not been supported by any grant.
Please feel free to remedy this deficiency.
What happened to all that material?
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
It's all a bit of a mystery.
“Unfortunately the [1930] expedition (no fault of Parrington's)
was ill-conceived and ill-prepared. They did collect the greater
part of the skeleton of a huge brachiosaurid dinosaur; but even
that was left for decades to rot in the basements of South
Kensington, the only elements that were ever prepared and
exhibited being two gigantic vertebrae.”
-- Charig's obituary of Parrington.
For whatever reason, most of the material is still in jackets.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Cervical P
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Cervicals S and T
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Cervicals S and T
That's cervical T
in the background
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Cervical U
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Dorsals A and B
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Dorsal centra Q and R
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
Long-bone fragment (distal femur?)
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
2. Reduced rugosity on ant/post faces of spine
Archbishop's
posterior
rugosity
consists of a
semicircular
region
...
with a low,
broad, rugose
postspinal
lamina below.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
2. Reduced rugosity on ant/post faces of spine
Archbishop's
posterior
rugosity
consists of a
semicircular
region
...
with a low,
broad, rugose
postspinal
lamina below.
The Natural History Museum's Tendaguru Brachiosaur Mike Taylor, University of Portsmouth
4. Absence of hyposphene
The Archbishop has NO hyposphene: just a narrow
“medial infrapostzygapophyseal” lamina.
BUT is this just a preparation defect?
Brachiosaurus brancai, HMN SII, D4.
This is a typical brachiosaur hyposphene.