Adelospondyli

Adelospondyls Temporal range: Late Mississippian, Serpukhovian PreꞒ Ꞓ O S D C P T J K Pg N
Life restoration of Adelospondylus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Sarcopterygii
Clade:	Tetrapodomorpha
Clade:	Stegocephali
Order:	†Adelospondyli Watson, 1930
Families and genera
†Acherontiscidae †Acherontiscus †Adelogyrinidae †Adelogyrinus †Adelospondylus †Dolichopareias †Palaeomolgophis

Adelospondyli is an order of elongated, presumably aquatic, Carboniferous amphibians (sensu lato). They have a robust skull roofed with solid bone, and orbits located towards the front of the skull. The limbs were almost certainly absent,^[1] although some historical sources reported them to be present. Despite the likely absence of limbs, adelospondyls retained a large part of the bony shoulder girdle. Adelospondyls have been assigned to a variety of groups in the past. They have traditionally been seen as members of the subclass Lepospondyli, related to other unusual early tetrapods such as "microsaurs", "nectrideans", and aïstopods.^[1][2][3] Analyses such as Ruta & Coates (2007) have offered an alternate classification scheme, arguing that adelospondyls were actually far removed from other lepospondyls, instead being stem-tetrapod stegocephalians closely related to the family Colosteidae.^[4]

Most adelospondyls belong to the family Adelogyrinidae, and prior to 2003 the order and family were considered synonymous. In 2003, Ruta et al. assigned Acherontiscus to the order as the only known non-adelogyrinid member.^[2] Members of this group are very rare; only six known specimens can be assigned to the five known genera with absolute confidence. These specimens are known from Mississippian (Serpukhovian Age) geological deposits in Scotland, and they were among the oldest "lepospondyls" known from fossils.^[2]