Haplocanthosaurus ‭(‬Simple spined lizard‭)‬

Short Info

Haplocanthosaurus ‭(‬Simple spined lizard‭)‬

Phonetic : Hap-loe-kan-foe-sore-us.

Named By : John Bell Hatcher‭ ‬-‭ ‬1903

Diet : Herbivore

Size : Estimated 14.8 meters long

Type of Dinosaur : Sauropod

Type Species : H.‭ ‬priscus (type),‭ ‬H.‭ ‬delfsi

Found in : USA,‭ ‬including Colorado and Wyoming‭ ‬-‭ ‬Morrison Formation

When it Lived : Late Jurassic, 154-142 million years ago

Haplocanthosaurus, which means “simple-spined lizard”, is a genus that includes intermediate sauropod dinosaurs. From incomplete fossil skeletons, two species are known, H. delfsi (pictured above) and H. priscus (pictured below). It lived between 155 and 152 million years old during the late Jurassic (Kimmeridgian) stage. H. priscus is the type species. The referred species H. delfsi, which was discovered in Colorado by Edwin Delfs, a young student at Colorado State University, USA, was also found. Haplocanthosaurus species were found in the Morrison Formation’s lowest layer, alongside Brontosaurus jahnahpin and Hesperosaurus majosi.


Haplocanthosaurus utterbacki skeletalIJReid, CC BY 4.0, via Wikimedia Commons


There are currently four Haplocanthosaurus specimens: one from H. delfsi and three from H. priscus. The type of H. delfsii is the only one that can be mounted. Mounted specimen of H. delfsi can now be found in the Cleveland Museum of Natural History. It has a fully speculative replica of the skull that was lost. Stratigraphic zones 1, 2 and 4 are home to this specimen. Recently described specimens from another region of the Morrison Formation were given to Haplocanthosaurus in 2014. They were described in a study that noted that Haplocanthosaurus was known from at least four specimens. These specimens were assigned to H. priscus, H. utterbacki, and H. sp. priscus; CM879, H. delfsi CMNH 10380, and H. sp. (MWC 8028). Haplocanthosaurus has been given seven additional specimens. or Haplocanthosauridae indet. For its discovery in Montana, one potential specimen was nicknamed “Big Monty”. It is believed to be 34m (110ft) in length. The specimen is controversial and little is known.

Haplocanthosaurus was one the smallest Morrison sauropods. Some Morrison sauropods could grow to lengths exceeding 20 meters or more than 66 feet, but Haplocanthosaurus was much smaller. It reached 14.8 meters (49ft) in length and weighed 12.8 metric tonnes (14.1 short tons).

Many elements are known about Haplocanthosaurus, but mainly vertebra. In the middle and cervical caudals of Apatosaurus, Camarasaurus, Cetiosaurus and Haplocanthosaurus, the intraprezygapophyseal lamina is separate from the root of the neural canal by a vertical midline lamina. The lateral edge becomes more roughened in the last few caudals as well as the most cranial dorsals. Hatcher (1901), interpreted this to mean that the attachment area was formed for the muscles, from which the capular blade was suspended.

Only Camarasaurus has the dorsoventrally elongate oval outline. Both Camarasaurus and Haplocanthosaurus have the parapophyses as oval facets along the craniolateral edge, and the sacral spines 1 through 3 fused.

OUMNH J13695 is a Cetiosaurus specimen. It has a horizontal ridge that runs along each of its lateral surfaces. This creates a subhexagonal transverse section. The area surrounding each articular face’s periphery is flattened, giving it a ‘bevelled look’. This also happens in Cetiosauriscus and Haplocanthosaurus.

Source: Wikipedia