The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis

The present study was undertaken in order to effect a comprehensive phylogenetic analysis of the order Pholidota, examining seven of the eight currently recognized extant species (absent is Manis culionensis, formerly recognized as a subspecies of Manis javanica) and nearly all the well-known fossil taxa, and employing a wide range of osteological characters from the entire skeleton. In addition, the relationship of pangolins to several putative early Tertiary relatives, including palaeanodonts and the enigmatic “edentate” Eurotamandua joresi, were investigated. The goal of the study was to improve understanding of the systematics and the biogeographic and evolutionary history of the pangolins. A computer-based cladistic analysis of phylogenetic relationships among seven extant species of pangolins, five extinct pangolin species (including all but one of the well-preserved taxa), as well as Eurotamandua and two genera of metacheiromyid palaeanodonts, Palaeanodon and Metacheiromys, was performed based upon 395 osteological characteristics of the skull and postcranial skeleton. Characters were polarized via comparison to the following successive outgroups: the basal feliform carnivoran Nandinia binotata and the hedgehog Erinaceus sp., a eulipotyphlan laursiatherian placental. A revised classification is presented based on the results of the analysis. The results support the monophyly of Pholidota and Palaeanodonta by providing new anatomical characters that can serve to diagnose a pangolin/palaeanodont clade, termed here Pholidotamorpha. Pholidota is defined so as to include all living and fossil pangolins, including all three taxa of middle Eocene “edentates” from the Messel fauna of Germany, among them Eurotamandua joresi. The results do not support the monophyly of the remaining two Messel “edentates” originally placed in the same genus Eomanis, which is restricted to the type species Eomanis waldi. Euromanis, new genus, is named with Eomanis krebsi Storch and Martin, 1994, as the type species, to form a new combination Euromanis krebsi (Storch and Martin, 1994). The analysis strongly supports the monophyly of a crown clade of pangolins diagnosed by many anatomical synapomorphies, the family Manidae. This crown clade is sister to the family Patriomanidae, which includes two Tertiary taxa, Patriomanis americana and Cryptomanis gobiensis, within the superfamily Manoidea. The relationship of the Tertiary European pangolin Necromanis to these two families is unresolved. Within Manidae, the extant species are divided into three well-supported, monophyletic genera, Manis for the Asian pangolins, Smutsia for the African ground pangolins, and Phataginus for the African tree pangolins. The latter two form a monophyletic African assemblage, the subfamily Smutsiinae. The biogeographic implications of this phylogeny are examined. A European origin for Pholidota is strongly indicated. The fossil record of pangolins would seem to support a European origin for the modern forms, with subsequent dispersal into sub-Saharan African and then to southern Asia, and the phylogeny produced in this analysis is consistent with such a scenario.