A new Oligo-Miocene dolphin from New Zealand: Otekaikea huata expands diversity of the early Platanistoide

Tanaka, Yoshihiro; Fordyce, R. Ewan

doi:10.26879/518

Cited by 29 publications

(92 citation statements)

References 22 publications

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“…Dorsally, the squamosal bears a tubercle-like squamosal prominence at the base of the zygomatic process; this appears to represent the anterior end of the anteroposteriorly short supramastoid crest, which terminates posterior to the temporal fossa. Medial to this a longitudinal trough-like secondary squamosal fossa is present; laterally a shallow fossa for the sternocephalicus muscle is present ( D neck muscle fossa of Tanaka & Fordyce 2015). The suture for the parietal is serrate, with parallel ridges and troughs, and the parietoÀsquamosal suture is open and unfused.…”

Section: Descriptionmentioning

confidence: 99%

A new eomysticetid from the Oligocene Kokoamu Greensand of New Zealand and a review of the Eomysticetidae (Mammalia, Cetacea)

Boessenecker

Fordyce

2016

Journal of Systematic Palaeontology

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Eomysticetids represent a worldwide, short-lived radiation of archaic baleen-bearing mysticetes that elucidate morphofunctional shifts and ontogenetic change amongst early Neoceti. Fossils of eomysticetids are now recorded from Oligocene marine rocks along the margins of the North Pacific (Japan), North Atlantic (South Carolina), and the Southern Ocean (New Zealand). The assemblage from New Zealand is diverse, with five species in three genera present during the Duntroonian stage (Chattian, 27.3À25.2 Ma). A new genus and species of eomysticetid from the lower Kokoamu Greensand of New Zealand, Matapa waihao gen. et sp. nov., increases the known diversity of Southern Hemisphere eomysticetids. Matapa uniquely exhibits a rounded margin of the occipital shield, and shares a mosaic of features seen in Northern Hemisphere eomysticetids such as a large squamosal prominence, an inflated and posteriorly rounded paroccipital process, and a double-faced posterior bullar facet with longitudinal ridges. The holotype specimen of Matapa waihao is ontogenetically immature, but ontogenetically static tympanoperiotic characters that diagnose this new species are shared by referred adult specimens. Matapa is uppermost Whaingaroan (28.1À27.3 Ma) in age, the oldest eomysticetid from New Zealand. Fossils of Matapa are recovered from both the modern west and east coast of New Zealand which, during the Oligocene, were on the margin of the Southern Ocean. Inclusion of Matapa within an earlier published cladistic analysis recovers Matapa as the earliest diverging member of the New Zealand eomysticetid clade, and confirms eomysticetid monophyly. The taxonomy, morphology and geochronological age of all known eomysticetids are reviewed.http://zoobank.org/urn:lsid:zoobank.org:pub:EE1CB5CC-618B-4ABA-9D97-5B9DEDD3470E

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Section: Descriptionmentioning

confidence: 99%

A new eomysticetid from the Oligocene Kokoamu Greensand of New Zealand and a review of the Eomysticetidae (Mammalia, Cetacea)

Boessenecker

Fordyce

2016

Journal of Systematic Palaeontology

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“…([36] #15, [37,38] #14; modified from Fordyce [27] #36; [40] #1418; [31] #10; [30] #2; [41,42] #10)43.Upper anterior ‘teeth’: about same size as upper posterior teeth (0); greatly enlarged (1); clearly smaller than upper posterior teeth or absent (2). ([36] #22, modified from Murakami et al . [37,38] #22)44.Cheek teeth entocingulum: present (0); absent (1).…”

Section: Resultsmentioning

confidence: 99%

A new fossil dolphinDilophodelphis fordyceiprovides insight into the evolution of supraorbital crests in Platanistoidea (Mammalia, Cetacea)

2017

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Many odontocete groups have developed enlarged facial crests, although these crests differ in topography, composition and function. The most elaborate crests occur in the South Asian river dolphin (Platanista gangetica), in which they rise dorsally as delicate, pneumatized wings anterior of the facial bones. Their position wrapping around the melon suggests their involvement in sound propagation for echolocation. To better understand the origin of crests in this lineage, we examined facial crests among fossil and living Platanistoidea, including a new taxon, Dilophodelphis fordycei, nov. gen. and sp., described herein, from the Early Miocene Astoria Formation of Oregon, USA. We measured the physical extent and thickness of platanistoid crests, categorized their relative position and used computed tomography scans to examine their internal morphology and relative bone density. Integrating these traits in a phylogenetic context, we determined that the onset of crest elaboration or enlargement and the evolution of crest pneumatization among the platanistoids were separate events, with crest enlargement beginning in the Oligocene. However, we find no evidence for pneumatization until possibly the Early Miocene, although certainly by the Middle Miocene. Such an evolutionary context, including data from the fossil record, should inform modelling efforts that seek to understand the diversity of sound generation morphology in Odontoceti.

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“…Following Tanaka & Fordyce (2015a), with the removal of the undescribed specimen OU 22125, and addition 4 allodelphinidae taxa ( Zarhinocetus errabundus , Goedertius oregonensis , Allodelphis pratti and Arktocara yakataga ). Also added were codings for four periotic characters (288–291) for Pomatodelphis inaequalis and Zarhachis flagellator .…”

Section: Supplemental Informationmentioning

confidence: 99%

Arktocara yakataga, a new fossil odontocete (Mammalia, Cetacea) from the Oligocene of Alaska and the antiquity of Platanistoidea

Boersma

Pyenson

2016

PeerJ

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The diversification of crown cetacean lineages (i.e., crown Odontoceti and crown Mysticeti) occurred throughout the Oligocene, but it remains an ongoing challenge to resolve the phylogenetic pattern of their origins, especially with respect to stem lineages. One extant monotypic lineage, Platanista gangetica (the Ganges and Indus river dolphin), is the sole surviving member of the broader group Platanistoidea, with many fossil relatives that range from Oligocene to Miocene in age. Curiously, the highly threatened Platanista is restricted today to freshwater river systems of South Asia, yet nearly all fossil platanistoids are known globally from marine rocks, suggesting a marine ancestry for this group. In recent years, studies on the phylogenetic relationships in Platanistoidea have reached a general consensus about the membership of different sub-clades and putative extinct groups, although the position of some platanistoid groups (e.g., Waipatiidae) has been contested. Here we describe a new genus and species of fossil platanistoid, Arktocara yakataga, gen. et sp. nov. from the Oligocene of Alaska, USA. The type and only known specimen was collected from the marine Poul Creek Formation, a unit known to include Oligocene strata, exposed in the Yakutat City and Borough of Southeast Alaska. In our phylogenetic analysis of stem and node-based Platanistoidea, Arktocara falls within the node-based sub-clade Allodelphinidae as the sister taxon to Allodelphis pratti. With a geochronologic age between ∼29–24 million years old, Arktocara is among the oldest crown Odontoceti, reinforcing the long-standing view that the diversification for crown lineages must have occurred no later than the early Oligocene.

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A new Oligo-Miocene dolphin from New Zealand: Otekaikea huata expands diversity of the early Platanistoide

Cited by 29 publications

References 22 publications

A new eomysticetid from the Oligocene Kokoamu Greensand of New Zealand and a review of the Eomysticetidae (Mammalia, Cetacea)

A new eomysticetid from the Oligocene Kokoamu Greensand of New Zealand and a review of the Eomysticetidae (Mammalia, Cetacea)

A new fossil dolphinDilophodelphis fordyceiprovides insight into the evolution of supraorbital crests in Platanistoidea (Mammalia, Cetacea)

Arktocara yakataga, a new fossil odontocete (Mammalia, Cetacea) from the Oligocene of Alaska and the antiquity of Platanistoidea

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