Sweet seventy-five and never been kissed. The Natural History Museum's Tendaguru brachiosaur Mike Taylor University of Portsmouth [email protected]

Sweet seventy-five and

never been kissed.

The Natural

History Museum's

Tendaguru brachiosaur

Mike Taylor

University of Portsmouth

[email protected]

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


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



The expeditions

used hundreds

of native

labourers

and recovered

many

spectacular

specimens.

Photo modified

from Maier 2003



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).



That's Diplodocus down

there, looking like a toy.



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”


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”


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 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 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


This actually compares

pretty well with HMN SII

Skeletal reconstruction modified

from Wedel 2000.

Pink bones were excavated in 1930.

Prepared material


Skeletal reconstruction modified

from Wedel 2000.

Pink bones were excavated in 1930.

Red bones have been prepared.

Migeod's 1931 account


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?


“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.


... 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 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


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?


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!


Four cervicals (3 visible)

Two good dorsals

Two dorsal centra

Long-bone fragment


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.


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.


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


Comparison with Brachiosaurus type specimens

Posterior dorsals of each specimen.

Archbishop (BMNH R 5937)

D8 and D9


(FMNH P 25107) D8


(HMN SII) D7


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.


Anomalous characters


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)


(left posterolateral, below)

Spine caps are roughly

semicircular with the flat

face at the back.


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


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.


has distinctive triangular rugosities on

both faces of the neural spine.


has a semicircular

rugosity, with the flat part

directed ventrally.


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.


has distinctive triangular rugosities on

both faces of the neural spine.


has a semicircular

rugosity, with the flat part

directed ventrally.


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.


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.


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


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.


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?


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.


Cervical P


Cervicals S and T


Cervicals S and T

That's cervical T

in the background


Cervical U


Dorsals A and B


Dorsal centra Q and R


Long-bone fragment (distal femur?)


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.


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.


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.

Documents

Sweet seventy-five and never been kissed. The Natural History Museum's Tendaguru brachiosaur Mike Taylor University of Portsmouth [email protected]