The name of the genus Maddenia, is in homage to the palaeontologist Richard Madden, for his contributions to the palaeontology of South America, whereas the name of the type species and only known, Maddenia lapidaria, derives of the Latinlapidarius, "of stone".[2]
Description
This species is based in the holotype MPEF PV 7735, a fragment of jawbone with molar and premolar teeth associated and a partial canine associated, in addition to several additional specimens that include isolated teeth and other fragments of jaws. From these remains it was established that Maddenia was a small astrapothere, near of 50% smaller than Astraponotus. Its molar were high, with complex crowns and with canines moderately developed, characteristics of the advanced astrapotheres of big size of the Oligocene and the Miocene (like Astrapotherium and Granastrapotherium), which suggests that it must to occupy a habitat differentiated regarding other forms of big size, and that by its anatomical characteristics constitutes an intermediate form between the primitive forms like Albertogaudrya and the astrapotherids like Parastrapotherium, with which conform sister taxa to the two subfamilies of the family Astrapotheriidae, Astrapotheriinae and Uruguaytheriinae.[2]
Phylogeny
Cladogram according to Bond et al., 2011, standing out the phylogenetic position of Maddenia:[3]