Outline of Eastern North Pacific Fossil Cetacean Assemblages

Barnes, Lawrence G.

doi:10.2307/2412508

Cited by 110 publications

(102 citation statements)

References 30 publications

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“…Prior reports have established that archaic toothless mysticetes (Eomysticetidae, Cetotheriidae, stem balaenopteroids) -with a few exceptions -were primarily Oligocene and Miocene in age (Barnes 1977;Fordyce and Muizon 2001). Pliocene fossils of Herpetocetus represent the geochronologically latest surviving examples of cetotheriids (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Pliocene fossils of Herpetocetus represent the geochronologically latest surviving examples of cetotheriids (Fig. 3;Barnes 1977;Boessenecker 2011a). Prior to this discovery, the youngest records of cetotheriids were Herpetocetus sp.…”

Section: Discussionmentioning

confidence: 99%

“…Within Pliocene marine mammal assemblages, Herpetocetus co-occurs with early representatives of modern mysticete genera, in addition to archaic balaenids, balaenopterids, and eschrichtiids (Barnes, 1977Whitmore, 1994Oishi and Hasegawa, 1995b;Whitmore and Kaltenbach, 2008).…”

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confidence: 99%

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Pleistocene survival of an archaic dwarf baleen whale (Mysticeti: Cetotheriidae)

Boessenecker

2013

Naturwissenschaften

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Pliocene baleen whale assemblages are characterized by a mix of early records of extant mysticetes, extinct genera within modern families, and late surviving members of the extinct family Cetotheriidae. Although Pleistocene baleen whales are poorly known, thus far they include only fossils of extant genera, indicating late Pliocene extinctions of numerous mysticetes alongside other marine mammals. Here, a new fossil of the late Neogene cetotheriid mysticete Herpetocetus is reported from the Lower to Middle Pleistocene Falor Formation of Northern California. This find demonstrates that at least one archaic mysticete survived well into the Quaternary Period, indicating a recent loss of a unique niche and a more complex pattern of Plio-Pleistocene faunal overturn for marine mammals than has been previously acknowledged. This discovery also lends indirect support to the hypothesis that the pygmy right whale (Caperea marginata) is an extant cetotheriid, as it documents another cetotheriid nearly surviving to modern times.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Pleistocene survival of an archaic dwarf baleen whale (Mysticeti: Cetotheriidae)

Boessenecker

2013

Naturwissenschaften

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“…Furthermore, among the early Miocene long-snouted forms, the familial affi nities of several other taxa are still debated. Indeed, due to the fragmentary state of the type series, relationships of members of the genera Argyrocetus Lydekker, 1893 (three species from the Northeast Pacifi c and Argentina) and Macrodelphinus Wilson, 1935 (one species from the Northeast Pacifi c) are not convincingly resolved (Kellogg 1932;Wilson 1935;Barnes 1976;Lambert 2005b).…”

Section: Introductionmentioning

confidence: 99%

A new archaic homodont toothed cetacean (Mammalia, Cetacea, Odontoceti) from the early Miocene of Peru

2015

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Apart from a few exceptions, extant odontocetes (toothed cetaceans) exhibit a roughly homodont dentition. The transition from basilosaurid-like double-rooted cheek teeth with accessory denticles to single-rooted conical teeth occurred during the late Oligocene-early Miocene. At that time, several clades of now extinct, homodont and predominantly long-snouted odontocetes appeared in the fossil record. Among them, members of the genera Argyrocetus Lydekker, 1893 and Macrodelphinus Wilson, 1935, from the early Miocene of the Northeast Pacific and Argentina, were tentatively attributed to the family Eurhinodelphinidae. However, due to the fragmentary state of the specimens, unambiguous apomorphies of the family could not be detected. Based on two well-preserved skulls with associated mandibular elements, discovered in early Miocene layers of the Chilcatay Formation (Pisco Basin, Peru), we report on a new genus and species of long-snouted homodont odontocete, Chilcacetus cavirhinus n. gen., n. sp. Characterized by, among others, the presence of alveoli on the anterior premaxillary portion of the rostrum, the lack of a lateral groove on the rostrum, anterodorsally elevated nasals, a possibly autapomorphic cavity between nasals and mesethmoid in the posterior wall of the bony nares, a high temporal fossa, and the absence of ankylosis along the mandibular symphysis, C. cavirhinus n. gen., n. sp. does not fit in any of the known odontocete families, but shares several morphological features with Argyrocetus spp. and Macrodelphinus. Our phylogenetic analysis, based on 77 characters for 35 odontocete taxa, suggests the existence of an early Miocene Eastern Pacific long-snouted homodont odontocete clade (with an hypothetical South Atlantic member, the poorly known Argyrocetus patagonicus Lydekker, 1893), distinct from the only superficially similar eoplatanistids and eurhinodelphinids. Furthermore, our consensus tree indicates an early branching of this new clade compared to other homodont odontocete lineages. Unfortunately, the results of the cladistic analysis presented here are not well supported; a reappraisal of Argyrocetus and Macrodelphinus is needed to more clearly define the new clade and bolster its phylogentic position

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“…The authors estimated the divergence time of two close-related dolphin species (Tursiops truncatus and T. aduncus) in DQB and DRB genes (>20 Mya) is much earlier than the separation date of these two species. The earliest fossils identifiable as Tursiops dated to only 4-7 Mya (Barnes 1990), as well as the emergence of oldest delphinid which is possible 11 Mya of latest Miocene (Barnes 1977). The authors postulated these allelic lineages of Tursiops MHC genes may emerge by gene duplication during the period of early radiation of small toothed whales (from late Oligocene to early Miocene, 22 Mya (Arnason et al, 2004).…”

Section: Phylogenetic Analyses Of Mhc Class II Genes In Cetaceansmentioning

confidence: 99%