A clade of herbivorous dinosaurs, known for their spinal plates, spiked tails, and tiny brains. Their heads were small and elongated, with beaks at the front and small chewing teeth inside fleshy cheeks. The shoulder girdle was very robust, with many species having horn-like spikes projecting from their shoulders. The torso widened and raised vertically from the shoulders to the hips, with the hind legs being significantly larger than the front ones. Their tails were held straight out, parallel to the ground, but were flexible in the horizontal plane, allowing them to swing the spiked tips (“thagomizers”) in a deadly arc.
The first known family of stegosaurians were the Huayangosauridae of middle Jurassic East Asia (eastern Laurasia at the time), such as Huayangosaurus and Bashanosaurus. These were the only members of the clade which seemed capable of running. They had small plates running in symmetrical rows down either side of their spines and long shoulder spikes. Their last, and largest, known member was Gigantspinosaurus, which lived in the late Jurassic and had huge shoulder spikes.
The larger Stegosaurids had diverged from the Huayangosauridae by the middle Jurassic, with Tuojiangosaurus being an early example. Its spinal plates were longer and more triangular than those of Huayangosaurids, and it had less flexible legs to support its greater weight. Another branch of Stegosaurids formed the Neostegosauria, which comprised two families: the Dacentrurinae and Stegosaurinae.
The Dacentrurinae had a wide distribution and were distinguished by the transformation of their rear spinal plates into spikes, and long necks. Adratiklit and Thyreosaurus lived in middle Jurassic North Africa (northern Gondwana), while the late Jurassic had Kentrosaurus in East Africa (central Gondwana), Dacentrurus in Europe (central Laurasia), and Miragaia in North America (western Laurasia).
Stegosaurines had broad, staggered spinal plates. In Yingshanosaurus, from middle Jurassic East Asia, these were fairly small and shoulder spikes were still present. Later members of the family had larger plates and no shoulder spikes. In East Asia these included the late Jurassic Jiangjunosaurus and early Cretaceous Wuerhosaurus. Late Jurassic North America had Hesperosaurus, and the famous Stegosaurus, which included the well-known S. stenops and the larger S. ungulatus.
Huayangosaurus
ST 21;
DX 10;
IQ 2;
HT 12.
HP 21;
Will 10;
Per 10;
FP 12;
Speed 5.50;
Dodge 8;
Move 5.
SM +3 (3 hexes), 1,100 lbs.
Shoulder spike (10): 2d impaling. Reach 1. Limited arc, sides.
Thagomizer (10): 2d+2 impaling. Reach 2. Limited arc, rear.
Trample (10): 2d / 1d−2 crushing. See GURPS Basic Set, p. 404.
Traits: Bad Sight (Low Resolution); DR 3 (Tough Skin); Enhanced Move 1 (Ground Speed 10; Costs Fatigue, 1 FP/second); Night Vision 1; Peripheral Vision; Quadruped; Wild Animal.
Skills: Survival (Woodlands)-10.
Use the same profile for Bashanosaurus.
For Gigantspinosaurus (1,500 lbs.) increase ST and HP to 23, and shoulder spike Reach to 2. Damage increases to 2d+3 with a shoulder spike or thagomizer, 2d+1 / 1d−1 with a trample.
Tuojiangosaurus
ST 38;
DX 9;
IQ 2;
HT 12.
HP 38;
Will 10;
Per 10;
FP 12;
Speed 4.00;
Dodge 7;
Move 5.
SM +4 (4 hexes), 7,000 lbs.
Shoulder spike (9): 4d impaling. Reach 1. Limited arc, sides.
Thagomizer (9): 4d+4 impaling. Reach 3. Limited arc, rear.
Trample (9): 4d / 2d−1 crushing. See GURPS Basic Set, p. 404.
Traits: Bad Sight (Low Resolution); DR 6 (Tough Skin); Night Vision 1; Peripheral Vision; Quadruped; Wild Animal.
Skills: Survival (Plains)-10.
For Yingshanosaurus (3,000 lbs.) reduce ST and HP to 29, SM to +3 (3 hexes), DR to 4, and thagomizer Reach to 2. Damage drops to 3d with the shoulder spikes, 3d+3 with the thagomizer, 3d / 1d with a trample.
Dacentrurus
ST 47;
DX 9;
IQ 2;
HT 12.
HP 47;
Will 10;
Per 10;
FP 12;
Speed 4.00;
Dodge 7;
Move 5.
SM +4 (5 hexes), 13,000 lbs.
Long Spines (5): 1d impaling. Reach C. Attack as a free action. See GURPS Basic Set, p. 88.
Thagomizer (9): 5d+6 impaling. Reach 4. Limited arc, rear.
Trample (9): 5d+1 / 2d+1 crushing. See GURPS Basic Set, p. 404.
Traits: Bad Sight (Low Resolution); DR 7 (Tough Skin); Long Neck 1*; Night Vision 1; Peripheral Vision; Quadruped; Wild Animal.
Skills: Survival (Plains)-10.
* see GURPS Furries, p. 12.
For Adratiklit (8,800 lbs.) reduce ST and HP to 41, and DR to 6. Damage drops to 4d+6 with the thagomizer, 4d+2 / 2d−1 with a trample. Change Survival specialty to (Swampland).
For Thyreosaurus (7,000 lbs.) reduce ST and HP to 38, and DR to 6. Damage drops to 4d+4 with the thagomizer, 4d / 2d−1 with a trample. Change Survival specialty to (Woodlands).
For Kentrosaurus (2,500 lbs.) reduce ST and HP to 27, SM to +3 (3 hexes), and DR to 4. Damage drops to 3d+2 with the thagomizer, 3d−1 / 1d with a trample.
For Miragaia (3,300 lbs.) reduce ST and HP to 30, and DR to 5. Damage drops to 3d+3 with the thagomizer, 3d / 1d+1 with a trample.
Stegosaurus stenops
ST 39;
DX 9;
IQ 2;
HT 12.
HP 39;
Will 10;
Per 10;
FP 12;
Speed 4.00;
Dodge 7;
Move 5.
SM +4 (4 hexes), 7,700 lbs.
Thagomizer (9): 4d+5 impaling. Reach 3. Limited arc, rear.
Trample (9): 4d+1 / 2d−1 crushing. See GURPS Basic Set, p. 404.
Traits: Bad Sight (Low Resolution); DR 6 (Tough Skin); Night Vision 1; Peripheral Vision; Quadruped; Wild Animal.
Skills: Survival (Plains)-10.
For S. ungulatus or Wuerhosaurus (9,000-9,300 lbs.) increase ST and HP to 42, DR to 7, and thagomizer Reach to 4. Damage increases to 4d+6 with the thagomizer, 4d+2 / 2d with a trample.
For Jiangjunosaurus (5,500 lbs.) reduce ST and HP to 35, and DR to 5. Damage drops to 4d+3 with the thagomizer, 4d−1 / 1d+2 with a trample.
For Hesperosaurus (7,700 lbs.) change Survival specialty to (Woodlands).