Eldeceeonis an extinctgenusofreptiliomorphfrom theMississippian(earlyCarboniferous) ofScotland.It is known from two fossil specimens found within theViséan-ageEast Kirkton QuarryinWest Lothian.Thetypeand only species,E. rolfei,was named in 1994.[1]Eldeceeonis thought to be closely related toembolomeres,but it has several distinguishing features including long limbs and a short trunk. Initially known from two crushed partial skeletons,[1]additional specimens have been reported by Ruta & Clack (2006).[2]Eldeceeonwas redescribed by Ruta, Clack, & Smithson (2020). The redescription supported affinities withSilvanerpeton,reconstructed a skull with larger eyes and a shorter snout, and emphasized potential correlations for an enlargepuboischiofemoralis internus2 muscle.[3]
In the East Kirkton Quarry, fossils ofEldeceeonwere found alongside another reptiliomorph calledSilvanerpeton.These genera are closely related to each other but represent an unusual group of reptiliomorphs that cannot be placed in any of the major reptiliomorphclades,but may be related to the earliest embolomeres. Unlike most embolomeres, which could grow over a meter long,Eldeceeonhas a much smaller body length of 35 centimetres (1.15 ft).[4]Compared to embolomeres, it has fewer dorsal vertebrae and much larger limbs relative to its body. The shortened spine and robust limbs ofEldeceeonsuggest it had a terrestrial lifestyle, distinguishing it from the primarily aquatic embolomeres which have relatively long bodies and short limbs. These adaptations also distinguish it fromSilvanerpeton,which is presumed to have been aquatic.[5]
The ribs ofEldeceeonare restricted to the front half of the spine, a characteristic that is not present in anytetrapods(four-limbed vertebrates) except mammals and their relatives.[1]Each vertebra is divided into a U-shapedpleurocentrumand a smallerintercentrum,like the vertebrae of the embolomereEoherpeton.[6]Thepectoralandpelvic girdlesresemble those of the embolomereProterogyrinus.[4]
^abcSmithson, T.R. (1994). "Eldeceeon rolfei,a new reptiliomorph from the Viséan of East Kirkton, West Lothian, Scotland ".Transactions of the Royal Society of Edinburgh: Earth Sciences.84(3–4): 377–382.doi:10.1017/s0263593300006180.
^Ruta, Marcello; Clack, Jennifer A. (2006). "A review ofSilvanerpeton miripede,a stem amniote from the Lower Carboniferous of East Kirkton, West Lothian, Scotland ".Transactions of the Royal Society of Edinburgh: Earth Sciences.97:31–63.doi:10.1017/S0263593300001395.
^abCarroll, R.L. (2009). "The Radiation of Carboniferous Amphibians".The Rise of Amphibians: 365 Million Years of Evolution.Baltimore: Johns Hopkins University Press. pp. 61–143.
^Garcia, W.J.; Storrs. G.W.; Greb, S.F. (2006). "The Hancock County tetrapod locality: A new Mississippian (Chesterian) wetlands fauna from western Kentucky". In Greb, S.F.; DiMichele, W.A. (eds.).Wetlands Through Time.Geological Society of America Special Paper. Vol. 399. Geological Society of America. pp. 155–167.doi:10.1130/2006.2399(08).
