Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand
The early evolution of toothless baleen whales (Chaeomysticeti) remains elusive despite a robust record of Eocene-Oligocene archaeocetes and toothed mysticetes. Eomysticetids, a group of archaic longirostrine toothless baleen whales fill in a crucial morphological gap between well-known toothed myst...
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University of Otago
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ftunivotagoour:oai:ourarchive.otago.ac.nz:10523/5742 2023-05-15T15:37:06+02:00 Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand Boessenecker, Robert Fordyce, R. Ewan 2015-06-24T22:20:57Z http://hdl.handle.net/10523/5742 en eng University of Otago http://hdl.handle.net/10523/5742 All items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated. Cetacea Oligocene Paleontology Evolution Taphonomy Ontogeny Mysticeti Eomysticetidae New Zealand Phylogeny Baleen Whales Baleen Morph Functional Morphology Thesis or Dissertation 2015 ftunivotagoour 2022-05-11T19:17:57Z The early evolution of toothless baleen whales (Chaeomysticeti) remains elusive despite a robust record of Eocene-Oligocene archaeocetes and toothed mysticetes. Eomysticetids, a group of archaic longirostrine toothless baleen whales fill in a crucial morphological gap between well-known toothed mysticetes and more modernized Neogene Mysticeti. Eomysticetids have been reported from South Carolina, USA, and Japan. Problematic fossils from New Zealand including "Mauicetus" lophocephalus Marples, 1956 and "Mauicetus" waitakiensis Marples, 1956, have been proposed as southern hemisphere eomysticetids. The fragmentary nature of this material has hampered interpretation of the relationships of these species. A large new collection of Eomysticetidae from the Oligocene Kokoamu Greensand and Otekaike Limestone of New Zealand permits reassessment of the skeletal anatomy, functional morphology, ontogeny, monophyly, and phylogenetic relationships of the family. This collection includes significant specimens including skulls, tympanoperiotics, mandibles, and postcrania of juveniles and adults. Discovery of new material similar to the "Mauicetus" of Marples permits referral of these species to the new genera Tohoraata and Tokarahia, recombined as Tohoraata waitakiensis and Tokarahia lophocephalus. More complete material of similar species Tohoraata raekohao and Tokarahia lophocephalus indicates that the two species of Tohoraata are stratigraphically separated whereas both species of Tokarahia were contemporaneous. The new genus and species Waharoa ruwhenua is represented by an ontogenetic series of skeletons that highlight the elongation of the palate during ontogeny; other morphofunctional aspects of the feeding apparatus suggest right whale-like skim feeding. The new genus and species Matapa waihao is the oldest and most archaic eomysticetid from New Zealand, indicating the presence of the family in the Southern Hemisphere by the earliest Chattian. Fragmentary specimens indicate the survival of eomysticetids to the Oligo-Miocene boundary or perhaps into the earliest Miocene, and the possible occurrence of the Japanese eomysticetid Yamatocetus in the Southern Hemisphere. Cladistic analysis confirms placement of the family Eomysticetidae as sister to crown Mysticeti. Eomysticetidae is for the first time recognized as being monophyletic; cladistic results indicate inclusion of Micromysticetus rothauseni. The Eomysticetidae were a specialized, worldwide, diverse, and short-lived Oligocene radiation of the earliest toothless mysticetes. Thesis baleen whales University of Otago: Research Archive (OUR Archive) New Zealand |
institution |
Open Polar |
collection |
University of Otago: Research Archive (OUR Archive) |
op_collection_id |
ftunivotagoour |
language |
English |
topic |
Cetacea Oligocene Paleontology Evolution Taphonomy Ontogeny Mysticeti Eomysticetidae New Zealand Phylogeny Baleen Whales Baleen Morph Functional Morphology |
spellingShingle |
Cetacea Oligocene Paleontology Evolution Taphonomy Ontogeny Mysticeti Eomysticetidae New Zealand Phylogeny Baleen Whales Baleen Morph Functional Morphology Boessenecker, Robert Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand |
topic_facet |
Cetacea Oligocene Paleontology Evolution Taphonomy Ontogeny Mysticeti Eomysticetidae New Zealand Phylogeny Baleen Whales Baleen Morph Functional Morphology |
description |
The early evolution of toothless baleen whales (Chaeomysticeti) remains elusive despite a robust record of Eocene-Oligocene archaeocetes and toothed mysticetes. Eomysticetids, a group of archaic longirostrine toothless baleen whales fill in a crucial morphological gap between well-known toothed mysticetes and more modernized Neogene Mysticeti. Eomysticetids have been reported from South Carolina, USA, and Japan. Problematic fossils from New Zealand including "Mauicetus" lophocephalus Marples, 1956 and "Mauicetus" waitakiensis Marples, 1956, have been proposed as southern hemisphere eomysticetids. The fragmentary nature of this material has hampered interpretation of the relationships of these species. A large new collection of Eomysticetidae from the Oligocene Kokoamu Greensand and Otekaike Limestone of New Zealand permits reassessment of the skeletal anatomy, functional morphology, ontogeny, monophyly, and phylogenetic relationships of the family. This collection includes significant specimens including skulls, tympanoperiotics, mandibles, and postcrania of juveniles and adults. Discovery of new material similar to the "Mauicetus" of Marples permits referral of these species to the new genera Tohoraata and Tokarahia, recombined as Tohoraata waitakiensis and Tokarahia lophocephalus. More complete material of similar species Tohoraata raekohao and Tokarahia lophocephalus indicates that the two species of Tohoraata are stratigraphically separated whereas both species of Tokarahia were contemporaneous. The new genus and species Waharoa ruwhenua is represented by an ontogenetic series of skeletons that highlight the elongation of the palate during ontogeny; other morphofunctional aspects of the feeding apparatus suggest right whale-like skim feeding. The new genus and species Matapa waihao is the oldest and most archaic eomysticetid from New Zealand, indicating the presence of the family in the Southern Hemisphere by the earliest Chattian. Fragmentary specimens indicate the survival of eomysticetids to the Oligo-Miocene boundary or perhaps into the earliest Miocene, and the possible occurrence of the Japanese eomysticetid Yamatocetus in the Southern Hemisphere. Cladistic analysis confirms placement of the family Eomysticetidae as sister to crown Mysticeti. Eomysticetidae is for the first time recognized as being monophyletic; cladistic results indicate inclusion of Micromysticetus rothauseni. The Eomysticetidae were a specialized, worldwide, diverse, and short-lived Oligocene radiation of the earliest toothless mysticetes. |
author2 |
Fordyce, R. Ewan |
format |
Thesis |
author |
Boessenecker, Robert |
author_facet |
Boessenecker, Robert |
author_sort |
Boessenecker, Robert |
title |
Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand |
title_short |
Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand |
title_full |
Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand |
title_fullStr |
Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand |
title_full_unstemmed |
Anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (Eomysticetidae) from the Oligocene of New Zealand |
title_sort |
anatomy, ontogeny, functional morphology, taphonomy, and phylogenetic relationships of archaic toothless mysticetes (eomysticetidae) from the oligocene of new zealand |
publisher |
University of Otago |
publishDate |
2015 |
url |
http://hdl.handle.net/10523/5742 |
geographic |
New Zealand |
geographic_facet |
New Zealand |
genre |
baleen whales |
genre_facet |
baleen whales |
op_relation |
http://hdl.handle.net/10523/5742 |
op_rights |
All items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated. |
_version_ |
1766367569712775168 |