Genus: Hylonomus DAWSON, 1860
Etymology: Greek, hylos, “woods, forest”, Greek, nomo, “to dwell” + us: Forest dweller.

Species: lyelli DAWSON, 1860
Etymology: In honor of Dawson's teacher, the geologist Sir Charles Lyell. 

Holotype: BMNH R 4168

Locality: Joggins, Cumberland County, Nova Scotia Province, Canada.

Horizon: Joggins Formation, coal group 26, section XII, division 4.

Biostratigraphy:

Age: Westphalian A, Lower Westphalian, Lower Upper Silesian stage, upper Bashkirian – lower Moscovian Epoch, Middle Pennsylvanian (Late Middle Carboniferous).

Material: Almost complete skeleton.

Referred material:

BMNH R 4167: Vertebrae, pelvis, femur, phalanges, ribs and scales.

NMC 10048: Vertebral column, pelvic girdle, both hind limbs and feet.

NMC 10047: Pterygoid, stapes, vertebrae, ribs, pelvic girdle, femora and scales.

NMC 10046: Vertebrae, pelvis, femora, fibula, humerus, ribs, scales and phalanges.

RM 12207: Palate, squamosal, dentary, articular, angular, coronoid, vertebrae, jugal, tibia and phalanges.

RM 12016a. Most of skull roof, pterygoids, dentary, vertebrae, ribs and clavicle.

FMNH PR 875: Cast of type.

 

= Hylerpeton curtidentatum DAWSON, 1876
Etymology:
= Fritschia curtidentata DAWSON, 1888

Holotype: RM 2.1126

Locality: Joggins, Cumberland County, Nova Scotia Province, Canada.

Horizon: Joggins Formation, coal group 26, section XII, division 4.

Biostratigraphy:

Age: Westphalian A, Lower Westphalian, Lower Upper Silesian stage, upper Bashkirian – lower Moscovian Epoch, Middle Pennsylvanian (Late Middle Carboniferous).

Material: Maxilla, premaxillae, lower jaws, humerus, femur, ribs, phalanges and scales.