In the East Pisco Basin (southern coast of Peru), the rich fossil record of cetaceans from the Pisco Formation is currently mainly concentrated in the Upper Miocene sequences P1 and P2. While some progress has recently been made in the study of the palaeobiological content of the Middle Miocene sequence P0, more work is needed to assess cetacean diversity in this unit and to analyse related palaeobiogeographical patterns. Based on a new skull including the cranium, ear bones, mandible, and teeth from the East Pisco Basin locality of Mal Paso, we describe a new large delphinidan species from the P0 sequence. Sharing strong morphological similarities with Miminiacetus pappus, from the Middle Miocene Calvert Formation (Maryland, USA), the new species is placed in the same genus and named Miminiacetus barrancai sp. nov. While it differs from M. pappus in, among others, its larger size and lower mandibular tooth count, the sister-group relationship recovered in our phylogenetic analyses points to an antitropical distribution for the genus Miminiacetus. This new record strengthens the cetacean faunal link between P0 and the Middle Miocene strata of the Calvert Formation. Miminiacetus spp. share several cranial and mandibular features with the modern beluga Delphinapterus leucas, possibly indicating some degree of specialization towards suction feeding in this large dolphin. Furthermore, the unusual occlusal wear on teeth of Miminiacetus spp. is reminiscent of the condition in D. leucas (in which it is related to alignment of upper and lower teeth) and is possibly linked to a jaw-clapping behaviour.
Varanid material from the Varswater Formation (Early Pliocene, 5.1 Ma) of Langebaanweg (LBW), Western Cape Province, South Africa, is described. The presence of Varanus in the LBW fauna was first reported by Hendey in 1981, but no further study has been conducted. The abundant material (consisting of 31 cranial remains, 38 vertebrae, one humerus and three ilia), allowed for a good understanding of the skeletal morphology of the LBW monitor lizard. The LBW material belongs to a single, extinct, previously undescribed, species, Varanus varswater sp. nov., which is diagnosed by the combination of six features, located on the premaxilla, maxilla, vomer, and vertebrae. A phylogenetic analysis was conducted to identify the affinities of the new species with other extant and extinct monitor lizards, using a matrix with 78 taxa and 6225 characters (495 of which are morphological). The results retrieve the new species in the African Varanus clade, together with the extinct Varanus rusingensis and the extant Varanus niloticus, Varanus albigularis, and Varanus exanthematicus, the new species being the earliest-branching member of a clade also including the latter two. Its phylogenetic position is of palaeobiogeographical interest and implies that a dispersal event from Southern Africa occurred for this clade. Lastly, the new Varanus from LBW represents both the first confirmed evidence for a monitor lizard inhabiting the south-westernmost region of the African continent, and the oldest Varanus record in South Africa.
A new trogoniform bird, Daniatrogon kochi gen. et sp. nov., is reported from the early Eocene Fur Formation in Demark. The holotype is a nearly complete skeleton in an exceptional state of preservation, and the presence of medullary bone shows the fossil to have been a breeding female. A phylogenetic analysis supports a sister-group relationship between D. kochi and a clade including the taxa Eotrogon, Masillatrogon and Primotrogon, as well as crown-group Trogoniformes. Daniatrogon kochi is, therefore, not only one of the oldest known trogoniforms, but also the phylogenetically earliest diverging one. Like other stem-group trogoniforms, it has a narrower beak than extant trogons and also differs from other trogoniforms in that the second toe is not reversed. This shows that the origin of heterodactyl feet preceded a widening of the beak in the evolution of trogons. A heterodactyl foot, in which the second toe is permanently reversed, is a key feature of extant and all other fossil trogons and is generally considered a perching adaptation that compensated for a weak hallux. However, the hallux is very long in D. kochi and it appears to have been reduced in the lineage leading to extant trogons. Stem-group trogoniforms may have been more actively moving during foraging, in which case the reduction of the hallux in trogoniforms is likely to have been due to the acquisition of a sedentary way of living.
