Storrs and Taylor, 1996




Rhetian-Hettangian boundary, Latest Triassic or Earliest Jurassic


Street, Somerset, England

Type species

T. hawkinsii

Other species


Referred material

To compile

The species Plesiosaurus hawkinsii was introduced in 1838 for a small plesiosaurian from Street, Somerset. The new genus name Thalassiodracon was erected decades later following an examination of a referred skull in Cambridge (CAMSM J.46986). Thalassiodracon means ‘Sea Dragon’, which “alludes to the colloquial description given to the Street marine reptile fauna by Hawkins” (Storrs and Taylor, 1996, p.404). Three specimens  were figured by Hawkins in his “Book of the great Sea Dragons” (1840). Thalassiodracon is frequently regarded as the most basal pliosauroid. T. hawkinsii is the type and only species. The type specimen is NHMUK 2018*, a complete skeleton.

The cranial anatomy of Thalassiodracon was described in detail by Storrs and Taylor (1996) and Benson et al. (2010).

<i>Thalassiodracon</i> lectotype specimen (NHMUK 2018*).
<i>Thalassiodracon</i> lectotype specimen (NHMUK 2018*), on display in the Natural History Museum , London.
Cast of the <i>Thalassiodracon</i> lectotype specimen (NHMUK 2018*), on display in the Bristol Museum and Art Gallery.
<i>Thalassiodracon</i> paralectotype (NHMUK 2020* [14551])
<i>Thalassiodracon</i> paralectotype (NHMUK 2020* [14551])
<i>Thalassiodracon</i> paralectotype (NHMUK 2020* [14551]) on display in the Natural History Museum London.
<i>Thalassiodracon</i> paralectotype (NHMUK 2022*[12549]).
<i>Thalassiodracon hawkinsi</i> model at Crystal Palace Park, by Benjamin Waterhouse Hawkins.
<i>Thalassiodracon</i> paralectotype (NHMUK 2020* [14551])