Haestasaurus
Name:
Haestasaurus
(Haesta lizard).
Phonetic: Hay-stah-sore-us.
Named By: Paul Upchurch, Philip D. Mannion
& Michael P. Taylor - 2015.
Synonyms: Pelorosaurus becklesii.
Classification: Chordata, Reptilia, Dinosauria,
Sauropodomorpha, Sauropoda, Macronaria?
Species: H. becklesii
(type).
Diet: Herbivore.
Size: Uncertain due to lack of fossil remains,
however, humerus is recorded as being 59.9 centimetres long,
ulna, 42.1 centimetres long and radius 40.4 centimetres long.
Using more complete genera such as Camarasaurus
results in a
reconstructed length of about 6.5 meters long, though this is just a
best guess.
Known locations: England - Hastings Beds Group.
Time period: Late Berriasian of the Cretaceous.
Fossil representation: Fore limb bones including
humerus (upper fore leg bone) and an ulna and radius (lower leg
bones). A skin impression is also known.
The
holotype bones of Haestasaurus were originally
found in 1852 by a
man named Samuel Husband Beckles who found them exposed by a low tide
on a coast not far from Hastings. These remains were studied by
Gideon Mantell (best remembered for naming Iguanodon)
who
considered them to represent a second species of the sauropod
Pelorosaurus,
P.
becklesii (in honour of Samuel Beckles who found the
bones). The
bones consisted of a partial fore limb and remained in the private
collection of Samuel Beckles until 1891 when they were acquired by
the British Museum of Natural History.
However,
speculation about the correct identity of the fossils
already started before they were acquired by the British Museum of
Natural History. Casts of the bones had been made before 1891,
and these were being studied as early as 1888. Initially, and
possibly unaware that the fossils had been used as a basis for a second
species of Pelorosaurus, Richard Lydekker
mistakenly attributed to
the fossil location of the bones as the Isle of Wight, which is quite
some way from Hastings. For the record, we currently do not know
the precise fossil location of the holotype bones other than somewhere
on the coastline of Hastings.
Another
noted American palaeontologist named Othniel Charles Marsh
considered the bones to represent a species of Morosaurus
in 1889.
Lydekker disagreed with this and instead chose to list it as a species
of Cetiosaurus
(in addition to this Morosaurus is now considered
to
be a synonym to Camarasaurus).
Much later in 1932, Friedrich
von Huene was of the opinion that Pelorosaurus becklesii
should be a
distinct genus but did not create a name. He also noted a similarity
to either Camarasaurus or Brachiosaurus,
again indicating a
similarity with macronarian sauropods. Later again in 1990, John
Stanton noted that fossils of Pelorosaurus becklesii
were not
co-generic with the Pelorosaurus type species P.
conybeari.
In
2015 Pelorosaurus becklesii was finally given its
own genus in a
study by Paul Upchurch, Philip Mannion and Michael Taylor. The new
name was Haestasaurus, meaning ‘Haesta lizard’
and was named
after an anglo-saxon war chief called Haesta, whose name would also
go on to derive the modern name of Hastings. Because only some fore
limb bones exist it has been difficult to definitively ascertain what
kind of sauropod Haestasaurus was. Earlier
interpretations of the
holotype bones suggest that Haestasaurus was a
macronarian sauropod
similar to Camarasaurus, and indeed this may
still be valid.
Although macronarian sauropods were most common in the Late Jurassic,
some are known in the early Cretaceous, with some genera such as
Brontomerus
being known to have existed even later that Haestasaurus.
Another idea is that Haestasaurus may be a
titanosauriform or even a
primitive titanosaur, which have their evolutionary roots within the
macronarian sauropods. The bones of Haestasaurus
do show a degree of
thickening to them which is a feature seen in titanosaurs, however
they are not thickened to a degree that would make them exclusively
titanosaurian, and may even represent a transitional stage.
Ultimately however more fossil discoveries are needed to reveal more
information about Haestasaurus.
Further reading
- The anatomy and phylogenetic relationships of ‘Pelorosaurus’
becklesii (Neosauropoda, Macronaria) from the
Early Cretaceous
of England. - PLoS ONE 10(6):e0125819:1-51. - P.
Upchurch, P. D. Mannion & M. P. Taylor - 2015.
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