[MARMAM] New publication: New Miocene fossil Allodelphinidae (Cetacea, Odontoceti, Platanistoidea) from the North Pacific Ocean

Toshiyuki KIMURA kimura at gmnh.pref.gunma.jp
Mon Apr 4 22:37:00 PDT 2016

Dear all,

We are pleased to announce our new publication:

Kimura, T. and Barnes, L.G. (2016). New Miocene fossil Allodelphinidae
(Cetacea, Odontoceti, Platanistoidea) from the North Pacific Ocean.
Bulletin of the Gunma Museum of Natural History, (20):1-58.

Abstract. Species in the extinct platanistoid family Allodelphinidae are
dolphin-like odontocete (echolocating) cetaceans known by fossils from
early and middle Miocene marine deposits around the eastern and western
margins of the North Pacific Ocean. Allodelphinids were relatively large
animals, having estimated adult total body lengths of approximately 3 to
5 meters, a long rostrum, the mandible extending to the end of the
rostrum with a fused mandibular symphysis, large and anteroposteriorly
elongated cervical vertebrae, and elongated humerus. The previously
named allodelphinid species, all from California, are early Miocene
Allodelphis pratti Wilson, 1935, and A. woodburnei Barnes and Reynolds,
2009, and middle Miocene Zarhinocetus errabundus (Kellogg, 1931).
Additional new species belonging in the family are Goedertius
oregonensis Barnes and Kimura, new genus and new species, from the early
Miocene Nye Mudstone in Lincoln County, Oregon, U.S.A.; Ninjadelphis
ujiharai Kimura, new genus and new species, from the early Miocene Awa
Group in Mie Prefecture, Japan; and Zarhinocetus donnamatsonae Barnes,
new species, from the late early Miocene to early middle Miocene Astoria
Formation in Grays Harbor County, Washington State, U.S.A. Goedertius
oregonensis is more derived than the species of Allodelphis.
Ninjadelphis ujiharai is more derived than Goedertius oregonensis and
has anteriorly retracted posterior ends of its premaxillae. Species of
Zarhinocetus Barnes and Reynolds, 2009, have a maxillary tuberosity on
each side of the base of the rostrum and a maxillary crest over the
orbit. Zarhinocetus donnamatsonae is more derived than N. ujiharai, but
more primitive than Zarhinocetus errabundus, which is the most derived
species in the family. Contrary to the general evolutionary trend in
cetaceans, allodelphinids evolved secondarily enlarged and
anteroposteriorly elongated cervical vertebrae, and all cervical
vertebrae remained un-fused to one another. Their elongated necks,
combined with a large occipital shield and thick nuchal crest on the
cranium, indicate that allodelphinids had well-developed muscles for
movements of the head. Their extremely long and slender rostra may have
allowed either raptorial or benthic feeding, and niche partitioning can
explain the diversity that is now being documented within the family.
Their swimming methods likely favored maneuverability but not speed.

Key words: Miocene fossil Cetacea, Platanistoidea, Allodelphinidae,
Allodelphis, Goedertius, Ninjadelphis, Zarhinocetus, odontocete benthic
feeding, odontocete swimming methods

PDF file is available here

or upon e-mail request to kimura at gmnh.pref.gunma.jp


Toshiyuki KIMURA, Ph.D.
Assistant Curator
Gunma Museum of Natural History
1674-1 Kamikuroiwa, Tomioka
Gunma 370-2345, Japan
tel: +81-274-60-1200
fax: +81-274-60-1250
e-mail: kimura at gmnh.pref.gunma.jp

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