[MARMAM] New publications on fossil platanistoid dolphins: Otekaikea and Waipatia
ewan.fordyce at otago.ac.nz
Fri May 15 14:20:53 PDT 2015
Two recent articles on fossil platanistoid dolphins from New Zealand are:
Tanaka Y, Fordyce RE 2015. A new Oligo-Miocene dolphin from New Zealand: Otekaikea huata expands diversity of the early Platanistoidea. Palaeontologia electronica 18.2.23A: 1-71. The New Zealand fossil dolphin Otekaikea huata (latest Oligocene to earliest Miocene, in the range 22.28 to 24.61 Ma) is here identified as an early new species in the clade Platanistoidea, which includes the endangered Ganges River dolphin (Platanista gangetica). Otekaikea huata is known only from the holotype, which comprises a partial skeleton from the marine Otekaike Limestone of the Hakataramea Valley, South Island. Otekaikea huata has multiple procumbent tusks passing back to otherwise near-homodont and polydont teeth, and an elevated face for the nasofacial muscles implicated in production of echolocation sounds. The skull vertex is asymmetrical and strongly left-skewed. Phylogenetic analyses based on morphological features place Otekaikea huata in the clade Platanistoidea. The new species adds to the diversity of the superfamily Platanistoidea near the Oligocene-Miocene boundary.
The pdf is freely available here:
Tanaka Y, Fordyce RE 2015. Historically significant late Oligocene dolphin Microcetus hectori Benham 1935: a new species of Waipatia (Platanistoidea). Journal of the Royal Society of New Zealand: 10.1080/03036758.2015.1016046. The late Oligocene dolphin Microcetus hectori Benham 1935 (Otekaike Limestone, Duntroonian, around 25.2 million years ago) is documented, involving redescription of the teeth, and new description of the formerly undescribed skull. A separate recent phylogenetic analysis that included skull features indicates that M. hectori belongs in the genus Waipatia, rather than with Microcetus ambiguus. Waipatia hectori is readily distinguished from the older Waipatia maerewhenua by features that include: more robust zygomatic process of the squamosal; larger foramen spinosum; long and slender postorbital process; more inflated cheek-teeth. The two species of Waipatia form a basal clade in the Platanistoidea, elucidating the relationships of the hitherto monotypic late Oligocene genus Waipatia.
The pdf is available here
(We have asked that the journal post a new version with less pixelated graphics)
or from Yoshi Tanaka yoshihiro.tanaka at otago.ac.nz
or from Ewan Fordyce ewan.fordyce at otago.ac.nz
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