Acherontiscus caledoniae (Carroll 1969; Namurian, Carboniferous; 1967/12/1 Royal Scottish Museum; Fig. 1) is a tiny slender aquatic amphibian with vestigial limbs and a large pectoral girdle. Carroll wrote: "Acherontiscus combiines cranial characteristics typical of lepospondyls with a vertebral structure resembling that of embolomeres" (like Proterogyrinus). "This form cannot be placed in any recognized amphibian orders but presumably represents an isolated lineage which originated prior to the establishment of the definitive characteristics which differentiate all known lepospondyls and labyrinthodonts." As a lepospondyl, "This genus provides the first conclusive evidence of the presence of multiple central element in the trunk region."
Here,
in the large reptile tree Acherontiscus nests between the microsaur, Microbrachis, and Adelogyrinus + Adelospondylus. Carroll recognized "The pattern of the skull roof of Acherontiscus resembles most closely that of the microsaur Microbrachis" a taxon presently known only from later Late Carboniferous strata (305 mya). |
