The earliest known member of the rorqual—gray whale clade (Mammalia, Cetacea

Eobalaenoptera harrisoni, gen. et sp. nov., is described from a partial skeleton collected from the middle Miocene Calvert Formation of Virginia. Characteristics of this taxon, particularly of the petrosal, indicate that the new whale is a member of the clade that includes the Balaenopteridae (rorquals) and Eschrichtidae (gray whales) to the exclusion of “cetotheres” and the Balaenidae (right whales). Some of the probable synapomorphies of this clade include an elongate pars cochlearis, a tubular internal auditory meatus, the greater petrosal nerve foramen on the tympanic side of the petrosal, the stylomastoid fossa extending onto the posterior process of the petrosal, no medial groove on the pars cochlearis, four digits on each forelimb, depressed supraorbital processes, and ascending processes of maxillae extending onto the vertex. The approximate 14-million-year age of the specimen makes it the oldest known member of the clade by some 3 to 5 million years, and extends the fossil record of this clade closer to the divergence time estimated by some recent molecular studies.

Smithsonian contributions to paleobiology, 2002

Emry, Robert J., editor. Cenozoic Mammals of Land and Sea: Tributes to the Career of Clay¬ ton E. Ray. Smithsonian Contributions to Paleobiology, 93, 372 pages, 197 figures, 11 plates, 46 tables, 2002.-This is a volume of collected papers published to honor the career of Clayton E. Ray, now Curator Emeritus in the Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, and Curator of Late Cenozoic Mammals and of Fossil Marine Mammals in the same department for more than 30 years before his retirement in 1994. The volume includes a preface, a biography and bibliography of Clayton E. Ray, and 19 papers devoted principally to Pleistocene mammals and to fossil marine mammals. Gary Morgan describes late Pleistocene mammalian faunas from several sites in southernmost Florida and discusses the Neotropical influence in Florida's Pleistocene faunas. Richard H. Tedford describes the basicranium of the Pleistocene giant wombat Phascolonus gigas Owen and dis¬ cusses its significance in marsupial phylogenetic reconstruction. Gerardo De luliis and A. Gor¬ don Edmund describe Vassallia maxima Castellanos, the only pre-Pleistocene pampathere known in which a skull and mandible are associated with osteoderms; the range of osteoderm variation in one associated individual allows them to synonymize other taxa that had been based on osteoderm differences. Paul W. Parmalee and Russell Wm. Graham report additional records of the giant beaver, Castoroides, from the mid-South. Frederick Grady, Joaquin Arroyo-Cabrales, and E. Ray Garton report the northernmost known occurrence of vampire bats in the Pleistocene of eastern North America. H. Gregory McDonald reports the second known occurrence of the badger Taxidea taxus in the Pleistocene of Kentucky and discusses the paleoecological implications of the occurrence. Jerry N. McDonald and George E. Lammers describe Bison antiquus from Ontario and discuss the evolution of bison in the Holocene of North America. Daryl P. Domning presents a new analysis and interpretation of the terres¬ trial posture in desmostylians. Thomas A. Demere and Annalisa Berta describe new material and present a phylogenetic analysis of the Miocene pinniped Desmatophoca oregonensis from Oregon. Irina A. Koretsky and Dan Grigorescu describe and evaluate the systematic position of the fossil monk seal Pontophoca sarmatica from the Miocene of eastern Europe. Irina A. Koretsky and Peter Holec describe a new, primitive, phocid pinniped from the early middle Miocene of Slovakia and discuss its bearing on the phylogeny and classification of pinnipeds. Irina A. Koretsky and Albert E. Sanders report remains of the oldest known phocid pinniped from the late Oligocene of South Carolina. R. Ewan Fordyce describes and discusses a bizarre archaic Oligocene dolphin from the eastern North Pacific, on which he bases a new species, genus, and subfamily. Christian de Muizon, Daryl P. Domning, and Darlene R. Ketten describe and discuss the paleobiology and behavior of an unusual walrus-convergent delphinoid ceta¬ cean from the early Pliocene of Peru. Susan D. Dawson and Michael D. Gottfried report paleopathologic conditions in a Miocene odontocete cetacean. Albert E. Sanders and Lawrence G. Barnes contribute two papers, both describing and analyzing new, primitive, cetotheriid mysticete cetaceans from the late Oligocene of South Carolina. James W. Westgate and Frank C. Whitmore, Jr., describe a new species of bowhead whale from the Pliocene Yorktown Forma¬ tion in Virginia. James G. Mead and Rosemary G. Dagit present an account of the search for the 1880s manuscript of J.A. Allen's unpublished monograph on the mammalian orders Cete and Sirenia; the manuscript was not found but the 12 plates that were prepared for it are pub¬ lished herein. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution's annual report. Annals of the Smithsonian Institution. SERIES COVER DESIGN: The trilobite Phacops rana Green.

Zoological Journal of the Linnean Society, 2012

A fossil pygmy right whale (Cetacea, Mysticeti, Neobalaenidae) with exquisitely preserved baleen is described for the first time in the history of cetacean palaeontology, providing a wealth of information about the evolutionary history and palaeobiogeography of Neobalaenidae. This exquisitely preserved specimen is assigned to a new genus and species, Miocaperea pulchra gen. et sp. nov., and differs from Caperea marginata Gray, 1846, the only living taxon currently assigned to Neobalaenidae, in details of the temporal fossa and basicranium. A thorough comparative analysis of the skeleton of M. pulchra gen. et sp. nov. and C. marginata is also provided, and forms the basis of an extensive osteology-based phylogenetic analysis, confirming the placement of M. pulchra gen. et sp. nov. within Neobalaenidae as well as the monophyly of Neobalaenidae and Balaenidae; the phylogenetic results support the validity of the superfamily Balaenoidea. No relationship with Balaenopteroidea was found by the present study, and thus the balaenopterid-like morphological features observed in C. marginata must have resulted from parallel evolution. The presence of M. pulchra gen. et sp. nov. around 2000 km north from the northernmost sightings of C. marginata suggests that different ecological conditions were able to support pygmy right whale populations in what is now Peru, and that subsequent environmental change caused a southern shift in the distribution of the living neobalaenid whales.

Systematic Biology, 2003

An odontocete cranium from Miocene deposits in northern Belgium is examined and referred to Caviziphius altirostris, a new genus and species of beaked whale. In the general architecture of its vertex and closed mesorostral canal, Caviziphius resembles the fossil genera Ziphirostrum and Choneziphius, but differs from all known ziphiids by a very deep excavated prenarial basin with a semicircular outline in lateral view. This peculiar cranial architecture of Caviziphius might indicate an advanced and efficient mechanism of sound production in this fossil ziphiid.

Scientific Reports

PeerJ

Background Balaenopterid mysticetes represent the most successful family-rank group of this clade. Their evolutionary history is characterized by a rich fossil record but the origin of the living genera is still largely not understood. Recent discoveries in the southern border of the North Sea revealed a number of well preserved fossil balaenopterid whales that may help resolving this problem. In particular, skull NMR 14035 shares morphological characters with the living humpback whale, Megaptera novaeangliae and, for this reason, its characteristics are investigated here. Methods The comparative anatomical analysis of the new specimen formed the basis of a new phylogenetic analysis of the Mysticeti based on a matrix including 350 morphological character states scored for 82 Operational Taxonomic Units. The stratigraphic age of the specimen was determined based on the analysis of the dinocyst assemblage recovered in the associated sediment. We assessed clade diversity in Balaenopter...

"The structure of the olfactory apparatus is not well known in both archaic and extant whales; the result of poor preservation in most fossils and locational isolation deep within the skulls in both fossil and Recent taxa. Several specimens now shed additional light on the subject. A partial skull of an archaic cetacean is reported from the Pamunkey River, Virginia, USA. The specimen probably derives from the upper middle Eocene (Piney Point Formation) and is tentatively assigned to the Protocetidae. Uncrushed cranial cavities associated with the olfactory apparatus were devoid of sediment. CT scans clearly reveal the dorsal nasal meatus, ethmoturbinates within the olfactory recess, the cribriform plate, the area occupied by the olfactory bulbs, and the olfactory nerve tract. Several sectioned skulls of the minke whale (Balaenoptera acutorostrata) were also examined, and olfactory structures are remarkably similar to those observed in the fossil skull from the Pamunkey River. One important difference between the two is that the fossil specimen has an elongate olfactory nerve tract. The more forward position of the external nares in extant balaenopterids when compared with those of extant odontocetes is interpreted to be the result of the need to retain a functional olfactory apparatus and the forward position of the supraoccipital/ cranial vertex. An increase in the distance between the occipital condyles and the vertex in balaenopterids enhances the mechanical advantage of the epaxial musculature that inserts on the occiput, a specialization that likely stabilizes the head of these enormous mammals during lunge feeding."

Fossil species of Balaena have previously been named on the basis of material from the Western Hemisphere, but all are founded upon undiagnostic material. The holotype of B. ricei new species consists of a partial skull, partial mandible, all major flip-per bones, and representatives of all types of vertebrae, allowing comparison with the two best-known European species. This study, together with the known occurrence of Balaena spe-cies in the Pliocene of Europe, strengthens the conclusion that bowhead whales were present on both sides of the North Atlantic Ocean at that time. By contrast, remains of Balaena have not been reported from Miocene deposits of the Atlantic coast of North America.

The evolution of biosonar (production of high-frequency sound and reception of its echo) was a key innovation of toothed whales and dolphins (Odontoceti) that facilitated phylogenetic diversification and rise to ecological predominance. Yet exactly when high-frequency hearing first evolved in odontocete history remains a fundamental question in cetacean biology. Here, we show that archaic odontocetes had a cochlea specialized for sensing high-frequency sound, as exemplified by an Oligocene xenorophid, one of the earliest diverging stem groups. This specialization is not as extreme as that seen in the crown clade. Paired with anatomical correlates for high-frequency signal production in Xenorophidae, this is strong evidence that the most archaic toothed whales possessed a functional biosonar system, and that this signature adaptation of odontocetes was acquired at or soon after their origin.

Geology Today, 2004

AI

PeerJ

Background The rich fossil record of rorqual and humpback whales (Cetacea, Mysticeti, Balaenopteridae) is mainly characterized by monotypic genera since genera including more than one species are extremely rare. The discovery of new species belonging to known genera would be of great importance in order to better understand ancestor-descendant relationships and paleobiogeographic patterns in this diverse group. Recent discoveries in the southern North Sea Basin yielded a number of reasonably well preserved fossil balaenopterids from the Late Miocene; this sample includes a balaenopterid skull from Liessel, The Netherlands, which shares key characters with Archaebalaenoptera castriarquati from the Pliocene of Mediterranean. This skull is permanently held by Oertijdmuseum, Boxtel, The Netherlands, with the number MAB002286 and is investigated here. Methods A detailed comparative anatomical analysis of the skull MAB002286 is performed in order to understand its relationships. The age o...

Nature, 2004

The pygmy right whale, Caperea marginata, is the least understood extant baleen whale (Cetacea, Mysticeti). Knowledge on its basic anatomy, ecology, and fossil record is limited, even though its singular position outside both balaenids (right whales) and balaenopteroids (rorquals 1 grey whales) gives Caperea a pivotal role in mysticete evolution. Recent investigations of the cetacean cochlea have provided new insights into sensory capabilities and phylogeny. Here, we extend this advance to Caperea by describing, for the first time, the inner ear of this enigmatic species. The cochlea is large and appears to be sensitive to low-frequency sounds, but its hearing limit is relatively high. The presence of a well-developed tympanal recess links Caperea with cetotheriids and balaenopteroids, rather than balaenids, contrary to the traditional morphological view of a close Caperea-balaenid relationship. Nevertheless, a broader sample of the cetotheriid Herpetocetus demonstrates that the presence of a tympanal recess can be variable at the specific and possibly even the intraspecific level. We describe the cochlea of the pygmy right whale. The cochlea is large and sensitive to low-frequency sounds. Possession of a tympanal recess links Caperea with Plicogulae (cetotheriids and balaenopteroids). However, this feature may be more variable than previously thought.

The Paleontological Society Special Publications, 1996

The partial skeleton of a new genus and species of protocetid cetacean was collected from Burke County in the Upper Coastal Plain of Georgia. Its age, based on associated calcareous nannoplankton and mollusks, is early Bartonian, ca. 39-41 Ma. It is thus approximately contemporaneous with the Egyptian Eocetus schweinfurthi and the oldest basilosaurids, and considerably younger than all other described protocetids. About 60 skeletal elements of a single individual were recovered, including the skull, left ramus, pelvis, 12 ribs, and 23 vertebrae. The specimen is informally designated the Vogtle whale, named after its locality, the Vogtle Electric Generating Plant. Its phylogenetic position was determined by parsimony analysis to be: (Pakicetus (Rodhocetus (Protocetus (Vogtle whale (Eocetus, Basilosauridae))))). Important dental characters of the Vogtle whale include double-rooted PI and pi, prominent cingulae, strongly wrinkled and ornamented enamel (heaviest on P2 and P3), and triple-rooted upper molars. The carinae of the upper cheek teeth (except the PI) possess small, blunt accessory cuspules; these are strongest and most numerous on the P3 and P4. These are interpreted as homologous with the larger, sharper accessory cusps characteristic of basilosaurid cheek teeth. The talonid of the lower molars bears a single, tall, laterally compressed cusp, the hypoconid; it is separated from the massive protoconid by a vertical, carnivore-like carnassial notch. The p4 also has a similar but smaller hypoconid. Large wear facets reveal that the lingual surfaces of the main cusps of the P4-M3 occluded with the labial surfaces of the p4-m3, forming a continuous series of carnassial-like shearing blades. The more anteriorly located teeth show only apical wear. In contrast, the basicranial region of the Vogtle whale's skull for the most part plesiomorphically resembles that ofProtocetus and other Lutetian protocetids. The bulla is attached to the basicranium at three points, including a robust, syndesmotic articulation with the paroccipital process. There is a narrow but extensive peribullar sinus isolating the promontorium from contact with the exoccipital and basioccipital, but no true pterygoid fossa, only a shallow depression formed on the alisphenoid and pterygoid. The ventral surface of the promontorium is mostly flat. The fenestra vestibuli opens laterally and is not visible in ventral view. Often known basicranial apomorphies distinguishing basilosaurid cetaceans from Protocetus, the Vogtle whale shares only one with the former, an enlarged stapedial fossa. Numerous recent discoveries of early cetaceans from Pakistan, northwestern India, and Africa have greatly narrowed the morphologic gap between terrestrial mammals (i.e., mesonychids) and Protocetus, which for. a long time was the oldest known whale. But no morphologic intermediaries between Protocetus and the next grade of cetacean evolution, the basilosaurids, were known except for a very limited number of specimens referred to Eocetus and Pappocetus. Analysis of the morphology of the Vogtle whale from the dual perspectives of phylogeny and functional anatomy permits a fuller understanding of the protocetid-basilosaurid transition. This is one of the critical steps in cetacean evolution, since it here that they became fully aquatic.

Biology Letters

Toothed whales (Cetacea: Odontoceti) are the most diverse group of modern cetaceans, originating during the Eocene/Oligocene transition approximately 38 Ma. All extant odontocetes echolocate; a single origin for this behaviour is supported by a unique facial source for ultrasonic vocalizations and a cochlea adapted for hearing the corresponding echoes. The craniofacial and inner ear morphology of Oligocene odontocetes support a rapid (less than 5 Myr) early evolution of echolocation. Although some cranial features in the stem odontocetes Simocetus and Olympicetus suggest an ability to generate ultrasonic sound, until now, the bony labyrinths of taxa of this grade have not been investigated. Here, we use µCT to examine a petrosal of a taxon with clear similarities to Olympicetus avitus . Measurements of the bony labyrinth, when added to an extensive dataset of cetartiodactyls, resulted in this specimen sharing a morphospace with stem whales, suggesting a transitional inner ear. This ...

PLoS ONE, 2011

Background: Anatomical comparisons of the ear region of baleen whales (Mysticeti) are provided through detailed osteological descriptions and high-resolution photographs of the petrotympanic complex (tympanic bulla and petrosal bone) of all extant species of mysticete cetaceans. Salient morphological features are illustrated and identified, including overall shape of the bulla, size of the conical process of the bulla, morphology of the promontorium, and the size and shape of the anterior process of the petrosal. We place our comparative osteological observations into a phylogenetic context in order to initiate an exploration into petrotympanic evolution within Mysticeti.

Molecular Phylogenetics and Evolution, 2013

The emergence of Cetacea in the Paleogene represents one of the most profound macroevolutionary transitions within Mammalia. The move from a terrestrial habitat to a committed aquatic lifestyle engendered wholesale changes in anatomy, physiology, and behavior. The results of this remarkable transformation are extant whales that include the largest, biggest brained, fastest swimming, loudest, deepest diving mammals, some of which can detect prey with a sophisticated echolocation system (Odontoceti-toothed whales), and others that batch feed using racks of baleen (Mysticeti-baleen whales). A broad-scale reconstruction of the evolutionary remodeling that culminated in extant cetaceans has not yet been based on integration of genomic and paleontological information. Here, we first place Cetacea relative to extant mammalian diversity, and assess the distribution of support among molecular datasets for relationships within Artiodactyla (even-toed ungulates, including Cetacea). We then merge trees derived from three large concatenations of molecular and fossil data to yield a composite hypothesis that encompasses many critical events in the evolutionary history of Cetacea. By combining diverse evidence, we infer a phylogenetic blueprint that outlines the stepwise evolutionary development of modern whales. This hypothesis represents a starting point for more detailed, comprehensive phylogenetic reconstructions in the future, and also highlights the synergistic interaction between modern (genomic) and traditional (morphological + paleontological) approaches that ultimately must be exploited to provide a rich understanding of evolutionary history across the entire tree of Life.

Bollettino della Società Paleontologica Italiana, 2023

A partial skeleton of a Pliocene balaenid whale (Mammalia, Cetacea, Mysticeti) is described and compared to a large set of extant and fossil Balaenidae. The specimen (MCRE 232834) includes a jugal, both mandibular rami and part of the postcranial skeleton including several vertebrae, complete ribs, hyoid, pelvis, a single scapula and a single partial forelimb. The specimen was found at a site in the vicinity of the San Valentino Castle, about 16 km S from Reggio Emilia, close to the town of Castellarano, Emilia Romagna (northern Italy). Molluscs and foraminifers indicate a late Zanclean age for MCRE 232834, constrained between 3.8 and 3.6 Ma. A taphonomic analysis revealed that after death the individual sunk on the sea floor upside down and underwent a series of biostratinomic processes eventually leading to the collapse of the ribcage and to the disarticulation of the posterior thoracic, lumbar and caudal vertebrae, together with the loss of several skeletal elements including the skull. Shark teeth and encrusting molluscs demonstrate that the specimen was exploited by different organisms during its decay. The study of the skeleton revealed that MCRE 232834 shows an abruptly converging anterior ends of the mandibular rami, well-developed olecranon process in the ulna, peculiar morphology of the cervical vertebrae and enlarged attachment sites for axial muscles in the ribs. Based on the morphology of the cervical vertebrae, mandible and scapula, MCRE 232834 can be assigned to a new genus and species of the family Balaenidae, i.e., Charadrobalaena valentinae n. gen., n. sp., which is part of a primitive clade of balaenids that is the sister group of the crown balaenid whales. A functional analysis of the vertebral column revealed that it was able of comparatively faster and more agile swimming with respect to the extant balaenid species.

PloS one, 2015

Cetacea are secondarily aquatic amniotes that underwent their land-to-sea transition during the Eocene. Primitive forms, called archaeocetes, include five families with distinct degrees of adaptation to an aquatic life, swimming mode and abilities that remain difficult to estimate. The lifestyle of early cetaceans is investigated by analysis of microanatomical features in postcranial elements of archaeocetes. We document the internal structure of long bones, ribs and vertebrae in fifteen specimens belonging to the three more derived archaeocete families - Remingtonocetidae, Protocetidae, and Basilosauridae - using microtomography and virtual thin-sectioning. This enables us to discuss the osseous specializations observed in these taxa and to comment on their possible swimming behavior. All these taxa display bone mass increase (BMI) in their ribs, which lack an open medullary cavity, and in their femora, whereas their vertebrae are essentially spongious. Humeri and femora show oppos...

Science (New York, N.Y.), 2010

Palaeontology, 2007

Abstract: A new basal balaenopterid genus and species, Archaebalaenoptera castriarquati, is described and compared with all the living and fossil members of the family Balaenopteridae and related fossil rorqual-like taxa. It was found in the Lower Pliocene of northern Italy, and is characterized by a supraoccipital with a transversely compressed anterior process, the zygomatic process of the squamosal diverging from the longitudinal axis of the skull, very long nasal bones, and subtle exposition of the parietal on the dorsal wall of the skull. It is primitive in having a maxilla with a long ascending process that is posteriorly unexpanded and round, and a dentary that is straight and not bowed outward, unlike that of living Balaenopteridae. In particular, the discovery of this new genus suggests that, among the early members of Balaenopteridae, the acquisition of the typical sutural pattern shown by maxilla, frontal, parietal and supraoccipital preceded the acquisition of the feeding-related traits that are characteristic of the family. The primitive morphology of the feeding-related structures of A. castriarquati (i.e. the straight dentary and the flat glenoid fossa of the squamosal) suggests that this whale was unable to undertake the intermittent ram feeding typical of Balaenopteridae as efficiently as living members of the family.

Journal of Mammalian Evolution, 2011

The origin of baleen whales, and their specialized mode of filter-feeding, marks an important event in the evolutionary history of mammals that gave rise to one of the most distinctive groups of animals alive today. Recent years have seen the description of a number of important new specimens, as well as the publication of a large number of phylogenetic analyses. Yet, despite this great effort, a broad consensus on even the most fundamental relationships within this group has so far remained elusive, a fact perhaps most strikingly reflected in the ongoing debate regarding the taxonomic placement of the extant gray and pygmy right whales, as well as the question of the relative closeness of relationship of all the extant members of the mysticete crown group. Here, I present the taxonomically most comprehensive phylogenetic analysis of extinct and extant baleen whales carried out to date, based on morphological data and utilizing both maximum parsimony and Bayesian methodologies. The results of this study were well resolved and consistent across methodologies. Apart from recovering a clade comprising the pygmy right whale, gray whales, and rorquals, a grouping new to morphological analyses but supported by a number of molecular studies, this investigation also revealed the former clade to be more closely related to a large number of extinct species than to right whales, thus contradicting previous notions of a closely related mysticete crown group. In addition, this analysis also identified a novel clade comprising nearly all the described archaic toothed mysticetes from the late Oligocene (about 23–28 Ma) to the exclusion of all toothless mysticetes. This finding is consistent with a basic assessment of the functional morphology of toothed mysticete vision, and may have implications for the evolution of mysticete filter-feeding and the recently proposed interpretation of some of these archaic taxa as transitional forms possessing both teeth and baleen at the same time.

Journal of Vertebrate Paleontology, 2007

Systematic Biology, 2007

Systematists disagree whether data from fossils should be included in parsimony analyses. In a handful of well-documented cases, the addition of fossil data radically overturns a hypothesis of relationships based on extant taxa alone. Fossils can break up long branches and preserve character combinations closer in time to deep splitting events. However, fossils usually require more interpretation than extant taxa, introducing greater potential for spurious codings. Moreover, because fossils often have more "missing" codings, they are frequently accused of increasing numbers of MPTs, frustrating resolution and reducing support. Despite the controversy, remarkably little is known about the effects of fossils more generally. Here we provide the first systematic study, investigating empirically the behavior of fossil and extant taxa in 45 published morphological data sets. First-order jackknifing is used to determine the effects that each terminal has on inferred relationships, on the number of MPTs, and on CF and RI as measures of homoplasy. Bootstrap leaf stabilities provide a proxy for the contribution of individual taxa to the branch support in the rest of the tree. There is no significant difference in the impact of fossil versus extant taxa on relationships, numbers of MPTs, and CF or RI. However, adding individual fossil taxa is more likely to reduce the total branch support of the tree than adding extant taxa. This must be weighed against the superior taxon sampling afforded by including judiciously coded fossils, providing data from otherwise unsampled regions of the tree. We therefore recommend that investigators should include fossils, in the absence of compelling and case specific reasons for their exclusion.

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