Haestasaurus

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Haestasaurus
Temporal range: Early Cretaceous, 140  Ma
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Haestasaurus.PNG
Left humerus of the type specimen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Neosauropoda
Clade: Macronaria
Genus: Haestasaurus
Upchurch, Mannion, & Taylor, 2015
Species:
H. becklesii
Binomial name
Haestasaurus becklesii
(Mantell, 1852)

Haestasaurus is a genus of herbivorous sauropod dinosaur, belonging to the Macronaria, that during the Early Cretaceous lived in the area of present-day England. The only species is Haestasaurus becklesii. [1]

Contents

Description

Restoration Haestasaurus life restoration.jpg
Restoration
Skin impression Haestasaurus skin.PNG
Skin impression

As a sauropod, Haestasaurus would have been a large quadrupedal long-necked dinosaur. Little information is available about the specifics of its build because only a forelimb is known of the animal.

An indication of the size of Haestasaurus is given by the length of the forelimb elements. The humerus is 599 millimetres long, the ulna 421 millimetres and the radius, situated next to the ulna in the lower arm, has a length of 404 millimetres. [1]

A 2015 study found several unique anatomical traits (autapomorphies) distinguishing Haestasaurus from related species. The inner front corner of the humerus is protruding, forming a processus entepicondylaris anterior. Between the front condyles of the lower humerus two small vertical ridges are present. The upper surface of the radius has, measured from front to rear, its largest width along the outer rim, which edge is nearly straight instead of strongly convex. The lower front of the radius is lightly concave between outer and inner ridges. A unique combination is present of a robust ulna, its upper surface having a width equalling more than 40% of the shaft length, with a slender radius having an upper width of less than 30% of total length. [1]

A rock associated with the forelimb, NHMUK R1868, was the first specimen known preserving parts of the sauropod skin. These probably are not impressions as the visible surface of the scales is convex, but natural casts. An area of 215 by 195 millimetres has been preserved. It shows non-overlapping hexagonal scales with a diameter of between ten and twenty-five millimetres. The scales gradually decrease in size, perhaps towards the elbow, to provide it greater flexibility. The scales strongly resemble skin impressions of later sauropod finds. [1] In 2022 a study reported the presence of small covering protuberances or papillae on the scales. With Neosauropoda, these would have served for a better camouflage or thermoregulation. [2] These structures had already been noted by Reginald Walter Hooley in 1917, [3] but had incorrectly been identified as representing the underside of the epidermis.

History of discovery and naming

In 1852, the collector Samuel Husband Beckles obtained a block of Wealden Sandstone that had become visible at low tide off the coast of East Sussex near Hastings. The precise location is today unknown. It proved to contain a large forelimb which was studied by Gideon Mantell. The same year, Mantell in a lecture named the find as a second species of Pelorosaurus : Pelorosaurus becklesii, the specific name honouring Beckles. [4]

Left ulna Haestasaurus ulna.PNG
Left ulna

Pelorosaurus becklesii at first received little attention, perhaps also because the fossils remained in the private collection of Beckles; they were acquired by the British Museum (Natural History) in 1891. In 1888, Richard Lydekker described a cast present in the museum, BMNH R28701, but seemed to be unaware of its status as a separate species and misidentified the discovery site as the Isle of Wight. [5] In 1889, the American paleontologist Othniel Charles Marsh coined the new combination Morosaurus becklesii. [6] However, this was not accepted by Lydekker who in subsequent publications referred the material to Cetiosaurus brevis. [7] [8] [9] In 1932, Friedrich von Huene concluded that P. becklesii represented a separate genus but provided no name, referring to it as "Gen. (?) becklesii", the question mark indicating an unknown genus that would have been a member of the Camarasaurinae within the Brachiosauridae. [10] In 1990, John Stanton McIntosh confirmed that the species was not co-generic with Pelorosaurus conybeari. [11]

In 2015, Paul Upchurch, Philip D. Mannion and Michael P. Taylor, having established that P. becklesii differed in many traits from Pelorosaurus conybeari and was not its sister species, named the separate genus Haestasaurus. The generic name is derived from Haesta, the presumed fifth century tribal Saxon chieftain whose existence has been deduced from the original name of Hastings, Haestingas , "the people of Haesta" (Old English hǣst ‘violence, violent’), and Greek sauros, "reptile". The combinatio nova is Haestasaurus becklesii. The type species remains Pelorosaurus becklesii. The name was published in an electronic journal, PLoS ONE. Such names require a Life Science Identifier which in this case is 9D2E9827-D6D5-444A-A01C-69CAE4FFCA22. [1] Haestasaurus was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals. [12]

Left radius Haestasaurus radius.png
Left radius

The holotype, NHMUK R1870, was found in a layer of the Hastings Beds dating from the Berriasian-Valanginian, roughly 140 million years old. It consists of a left forelimb containing the associated humerus, ulna and radius. Specimen NHMUK R1868 was part of the original block and consists of a natural cast of a part of the skin, near the elbow. When the Beckles Collection was acquired, a metacarpal was referred to P. becklesii, specimen NHMUK R1869, but its large size precludes its belonging to the holotype. [1]

Relationships

By the end of the twentieth century, most researchers agreed that P. becklesii was a member of the Titanosauriformes, possibly specifically within the Titanosauria. In the latter case it would have been one of the oldest known European titanosaurs. The 2015 study performed some detailed cladistic analyses to establish the exact position of Haestasaurus in the evolutionary tree. Due to the limited material available however, it proved impossible to obtain a single solution to this problem. Two major alternatives presented themselves. One possibility was that Haestasaurus was indeed a, basal, member of the Titanosauria. Alternatively, Haestasaurus was a basal member of the larger clade of the Macronaria, a close relative of Camarasaurus , Janenschia or Tehuelchesaurus . The authors favoured the last possibility because the traits pointing to a membership of the Titanosauria, such as a robust humerus and a robust ulna, could easily have been developed in a process of convergent evolution, as adaptations for weight-bearing. Haestasaurus would then represent a rare late-surviving basal macronarian. [1]

Related Research Articles

<i>Camarasaurus</i> Camarasaurid sauropod dinosaur genus from Late Jurassic Period

Camarasaurus was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch, between 155 and 145 million years ago.

<i>Titanosaurus</i> Extinct genus of dinosaurs

Titanosaurus is a dubious genus of sauropod dinosaurs, first described by Richard Lydekker in 1877. It is known from the Maastrichtian Lameta Formation of India.

<i>Pelorosaurus</i> Genus of dinosaur

Pelorosaurus is a genus of titanosauriform sauropod dinosaur. Remains referred to Pelorosaurus date from the Early Cretaceous period, about 140-125 million years ago, and have been found in England and Portugal. Thomas Holtz estimated its length at 24 meters.

<i>Jainosaurus</i> Extinct genus of dinosaurs

Jainosaurus is a genus of titanosaurian sauropod dinosaur of India and wider Asia, which lived in the Maastrichtian. It is thought to have been about the same size as its contemporary relative Isisaurus, measuring 18 metres (59 ft) long and weighing 15 metric tons. The humerus of the type specimen is 134 centimetres long.

<i>Argyrosaurus</i> Genus of herbivorous titanosaurian sauropod dinosaur

Argyrosaurus is a genus of titanosaurian sauropod dinosaur that lived about 70 million years ago, during the Late Cretaceous Period of what is now Argentina.

<i>Cetiosaurus</i> Extinct species of reptile

Cetiosaurus meaning 'whale lizard', from the Greek keteios/κήτειος meaning 'sea monster' and sauros/σαυρος meaning 'lizard', is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Period, living about 168 million years ago in what is now Britain.

<i>Altispinax</i> Genus of reptiles (fossil)

Altispinax is a genus of large predatory theropod dinosaur from the Early Cretaceous period of what is now the Wadhurst Clay Formation of East Sussex, England.

<i>Cetiosauriscus</i> Genus of reptiles (fossil)

Cetiosauriscus is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian in what is now England. A herbivore, Cetiosauriscus had — by sauropod standards — a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about 15 m (49 ft) long and between 4 and 10 t in weight.

<span class="mw-page-title-main">Macronaria</span> Extinct clade of dinosaurs

Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located. Fossil evidence suggests that macronarian dinosaurs lived from the Middle Jurassic (Bathonian) through the Late Cretaceous (Maastrichtian). Macronarians have been found globally, including discoveries in Argentina, the United States, Portugal, China, and Tanzania. Like other sauropods, they are known to have inhabited primarily terrestrial areas, and little evidence exists to suggest that they spent much time in coastal environments. Macronarians are diagnosed through their distinct characters on their skulls, as well as appendicular and vertebral characters. Macronaria is composed of several subclades and families notably including Camarasauridae and Titanosauriformes, among several others. Titanosauriforms are particularly well known for being some of the largest terrestrial animals to ever exist.

<i>Janenschia</i> Extinct genus of dinosaurs from late Jurassic in Lindi Region, Tanzania

Janenschia is a large herbivorous sauropod dinosaur from the Late Jurassic Tendaguru Formation of Lindi Region, Tanzania around 155 million years ago.

Dinodocus is a genus of sauropod dinosaur, named by Richard Owen in 1884. The name is now usually considered a nomen dubium. The only species, D. mackesoni, a name given to some fossil bones from the Lower Greensand Group of Hythe, Kent, England, were formerly placed in the genus Pelorosaurus, but a review by Upchurch et al. (2004) concluded that Dinodocus is a nomen dubium.

<i>Bothriospondylus</i> Extinct genus of dinosaurs

Bothriospondylus is a dubious genus of neosauropod sauropod dinosaur. It lived during the Late Jurassic in England, and the type and only species is B. suffossus.

Eucamerotus was a genus of sauropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation (Wealden) of the Isle of Wight, England.

<i>Oplosaurus</i> Extinct genus of dinosaurs

Oplosaurus was a genus of sauropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is known from a single tooth usually referred to the contemporaneous "wastebasket taxon" Pelorosaurus, although there is no solid evidence for this.

<i>Ornithopsis</i> Extinct genus of dinosaurs

Ornithopsis is a genus of sauropod dinosaur, from the Early Cretaceous of England. The type species, which is the only species seen as valid today, is O. hulkei, which is only known from fragmentary remains, and has been regarded by many authors as dubious.

<span class="mw-page-title-main">Wealden Group</span>

The Wealden Group, occasionally also referred to as the Wealden Supergroup, is a group in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental (freshwater) facies sedimentary rocks of Berriasian to Aptian age and thus forms part of the English Lower Cretaceous. It is composed of alternating sands and clays. The sandy units were deposited in a flood plain of braided rivers, the clays mostly in a lagoonal coastal plain.

<span class="mw-page-title-main">Camarasauridae</span> Extinct family of dinosaurs

Camarasauridae is a family of sauropod dinosaurs. Among sauropods, camarasaurids are small to medium-sized, with relatively short necks. They are visually identifiable by a short skull with large nares, and broad, spatulate teeth filling a thick jaw. Based on cervical vertebrae and cervical rib biomechanics, camarasaurids most likely moved their necks in a vertical, rather than horizontal, sweeping motion, in contrast to most diplodocids.

<span class="mw-page-title-main">Neosauropoda</span> Extinct clade of dinosaurs

Neosauropoda is a clade within Dinosauria, coined in 1986 by Argentine paleontologist José Bonaparte and currently described as Saltasaurus loricatus, Diplodocus longus, and all animals directly descended from their most recent common ancestor. The group is composed of two subgroups: Diplodocoidea and Macronaria. Arising in the early Jurassic and persisting until the Cretaceous-Paleogene extinction event, Neosauropoda contains the majority of sauropod genera, including genera such as Apatosaurus, Brachiosaurus, and Diplodocus. It also includes giants such as Argentinosaurus, Patagotitan and Sauroposeidon, and its members remain the largest land animals ever to have lived.

<span class="mw-page-title-main">Lithostrotia</span> Extinct clade of dinosaurs

Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch et al. in 2004 as the most recent common ancestor of Malawisaurus and Saltasaurus and all the descendants of that ancestor. Lithostrotia is derived from the Ancient Greek lithostros, meaning "inlaid with stones", referring to the fact that many known lithostrotians are preserved with osteoderms. However, osteoderms are not a distinguishing feature of the group, as the two noted by Unchurch et al. include caudal vertebrae with strongly concave front faces (procoely), although the farthest vertebrae are not procoelous.

Rhomaleopakhus is a genus of mamenchisaurid sauropod, dinosaur from the Late Jurassic Kalaza Formation of China. The type and only species is Rhomaleopakhus turpanensis.

References

  1. 1 2 3 4 5 6 7 Upchurch P., Mannion P.D., Taylor M.P., 2015, "The Anatomy and Phylogenetic Relationships of “Pelorosaurusbecklesii (Neosauropoda, Macronaria) from the Early Cretaceous of England", PLoS ONE10(6): e0125819. doi : 10.1371/journal.pone.0125819
  2. Pittman M, Enriquez NJ, Bell PR, Kaye TG, Upchurch P (2022). "Newly detected data from Haestasaurus and review of sauropod skin morphology suggests Early Jurassic origin of skin papillae". Communications Biology. 5 (1): Article number 122. doi: 10.1038/s42003-022-03062-z . PMID   35145214.
  3. Hooley, R.W. 1917. "On the integument of Iguanodon bernissartensis Boulenger, and of Morosaurus becklesii Mantell". Geological Magazine6: 148–150
  4. Mantell G.A., 1852, "On the structure of the Iguanodon and on the fauna and flora of the Wealden Formation", Notice: Proceedings of the Royal Institute of Great Britain. 18521: 141–146
  5. Lydekker R., 1888, "Note on a new Wealden Iguanodont and other Dinosaurs", Quarterly Journal of the Geological Society44: 46–61
  6. Marsh O.C., 1889, "Comparison of the principal forms of the Dinosauria of Europe and America", American Journal of Science (series 3), 37: 323–330
  7. Nicholson H.A. & Lydekker R., 1889, Manual of Palaeontology Volume 2. Edinburgh and London: Blackwood
  8. Lydekker R., 1890, "On remains of small sauropodous dinosaurs from the Wealden", Quarterly Journal of the Geological Society of London, 46: 182–184
  9. Lydekker R., 1893, "On a sauropodous dinosaurian vertebra from the Wealden of Hastings", Quarterly Journal of the Geological Society49: 276–280
  10. Von Huene, F., 1932, Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte, Monographien zur Geologie und Palaeontologie 1(4), Leipzig: Gebrueder Borntraeger pp. 361
  11. McIntosh J.S., 1990, "Sauropoda". In: Weishampel D.B., Dodson P., Osmólska H., (editors), The Dinosauria. First Edition, Berkeley: University California Press, pp. 345–401
  12. "The Open Access Dinosaurs of 2015". PLOS Paleo.