Annalisa Berta

San Diego State University | SDSU · Department of Biology

The transition in Mysticeti (Cetacea) from capture of individual prey using teeth to bulk filtering batches of small prey using baleen ranks among the most dramatic evolutionary transformations in mammalian history. We review phylogenetic work on the homology of mysticete feeding structures from anatomical, ontogenetic, and genomic perspectives. Si...

A newly discovered fossil dolphin shows that modern killer and false-killer whales evolved from fish-eating ancestors. While today both species occasionally feed on large warm-blooded prey, including seals and other whales, this diet specialization has evolved only recently.

The transition in Mysticeti (Cetacea) from capture of individual prey using teeth to bulk filtering batches of small prey using baleen ranks among the most dramatic evolutionary transformations in mammalian history. We review phylogenetic work on the homology of mysticete feeding structures from anatomical, ontogenetic, and genomic perspectives. Si...

The earliest phocid seals evolved 30–24 million years ago (Ma) in the western North Atlantic. There remains uncertainty in evolutionary relationships, with molecular data positioning phocids as the sister group to all other pinnipeds (fur seals, sea lions, and walruses), while morphology places them as sister to the extinct Desmatophocidae. The two...

Fossils have stirred the imagination globally for thousands of years, starting well before they were recognized as the remains of once-living organisms and proxies of former worlds. This volume samples the history of art about fossils and the visual conceptualization of their significance starting with biblical and mythological depictions, extendin...

Apart from mythological drawings (e.g. unicorns and mermaids), some appearing during classical times, marine mammals have been the subject of palaeoart since the seventeenth century. Whales were the first marine mammals to be portrayed in detailed pencil and ink scientific illustrations printed as woodcuts and copper engravings. The early and mid t...

Society of Vertebrate Paleontology and Susan TURNER, former DAAD Professor and Emeritus member SVP cooperated over three years to create a first definitive history of Women in Vertebrate Paleontology, published in October 2020 by the Johns Hopkins University Press, with supplementary material on their website. This book aims to encourage more girls...

A recent reappraisal of two passages in Leonardo da Vinci’s Codex Arundel, in which the then young Leonardo reports on visiting a cave and on some sort of ʽmarine monster’, has led to the proposition that Leonardo observed and wrote on fossil remains of a whale preserved in a cave. Whereas this hypothesis appears reasonable overall, some problems p...

I coauthored 10 chapters on pan-carnivoran clade names in Phylonyms: A Companion to the PhyloCode (ed. by K. de Queiroz K., P. D. Cantino, and J. A. Gauthier), https://doi.org/10.1201/9780429446276: (1) Pan-Carnivora, pp. 979–982; (2) Carnivora, pp. 983–987; (3) Pan-Feliformia, pp. 989–991; (4) Feliformia, pp. 993–998; (5) Pan-Caniformia, pp. 999–1...

Extant baleen whales (Mysticeti) share a distinct suite of extreme and unique adaptations to perform bulk filter feeding, such as a long, arched skull and mandible and the complete loss of adult dentition in favor of baleen plates. However, mysticetes still develop tooth germs during ontogeny. In the fossil record, multiple groups document the tran...

Marine mammals are key components of aquatic ecosystems. Feeding strategies identified in extant cetaceans, pinnipeds, sirenians, marine otters, and polar bears are associated with anatomical specializations of the head (rostrum, palate, temporomandibular joint, teeth/baleen, mandible). Genetic and ontogenetic evidence of skull and tooth morphology...

A look at many of the women who contributed to vertebrate palaeontology in Australasia in the 20th century

Researching the history of women who have contributed to the field of vertebrate palaeontology in Australasia from the early 20th century onward

Adaptations for feeding underwater were crucial to the success of pinnipeds (seals, sea lions, and walruses) in their transition from terrestrial to aquatic habitats. Extant phocids (true seals) use multiple feeding strategies—biting, filter, and suction feeding—to capture and consume prey, and each strategy is associated with cranial, mandibular,...

Research Infrastructures (RIs) are facilities, resources and services used by the scientific community to conduct research and foster innovation. LifeWatch ERIC has developed various virtual research environments, which include many virtual laboratories (vLabs) offering high computational capacity and comprehensive collaborative platforms that supp...

Research Infrastructures (RIs) are facilities, resources and services used by the scientific community to conduct research and foster innovation. LifeWatch ERIC has developed various virtual research environments, which include many virtual laboratories (vLabs) offering high computational capacity and comprehensive collaborative platforms that supp...

Previous hypotheses for the origin and diversification of pinnipeds have followed a narrative approach based mostly on dispersalist (i.e., center of origin) explanations. Using an analytical approach, we present a testable hypothesis to explain the evolutionary biogeography of pin-nipedimorphs (fur seals, sea lions, walruses, seals, and their fossi...

The oldest definitive pinniped fossils date from approximately 30.6-23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phoci...

Research Infrastructures (RIs) are facilities, resources and services used by the scientific community to conduct research and foster innovation. LifeWatch ERIC has developed various virtual research environments, which include many virtual laboratories (vLabs) offering high computational capacity and comprehensive collaborative platforms that supp...

Uncertainty in marine mammal taxonomy is increasingly being addressed using molecular genetic data. We examined 32 peer-reviewed articles published between 1994 and 2011to review methodological practices, consistency of markers and analytical methods, and overall quality of arguments used when genetic data have been employed to delimit new species...

Cetacean taxonomy continues to be in flux and molecular genetic analyses examining alpha taxonomy in cetaceans have relied heavily on the mitochondrial DNA control region. However, there has been little consistency across studies; a variety of metrics and levels of divergence have been invoked when delimiting new cetacean species and subspecies. Us...

Marine mammals have long captured the attention of humans. Ancient peoples etched seals and dolphins on the walls of Paleolithic caves; today, engineers develop microprocessors to track these denizens of the deep. This groundbreaking book from highly respected marine mammal paleontologist Annalisa Berta delves into the story of the extraordinary ad...

The origin of baleen and filter feeding in mysticete cetaceans occurred sometime between approximately 34 and 24 million years ago and represents a major macroevolutionary shift in cetacean morphology (teeth to baleen) and ecology (raptorial to filter feeding). We explore this dramatic change in feeding strategy by employing a diversity of tools an...

The overexploitation of whales, seals, sea cows, and sea otters has resulted in seriously reduced population sizes, the extinction of several species, and the endangered status of several others. The recognition of marine mammals as crucial natural resources and valued ecosystem components that require protection has resulted in the establishment o...

Marine mammals are defined and their adaptations reviewed in this introductory chapter. Extant marine mammals include more than 125 species with representatives in three mammalian orders: Carnivora: pinnipeds, marine otters, and polar bears; Cetacea: whales, dolphins, and porpoises; and Sirenia: manatees and dugongs. Objectives are identified and t...

One adaptation crucial to the survival of mammalian lineages that secondarily transitioned from land to water environments was the ability to capture and consume prey underwater. Phocid seals have evolved diverse feeding strategies to feed in the marine environment, and the objectives of this study were to document the specialized feeding morpholog...

Odontocete ear complexes or tympanoperiotic complexes (TPCs) were compared for asymmetry. Left and right TPCs were collected from one long-beaked common dolphin (Delphinus capensis) and one Amazon River dolphin (Inia geoffrensis). Asymmetry was assessed by volumetric comparisons of left and right TPCs and by visual comparison of superimposed models...

Information is scarce on gray whale (Eschrichtius robustus) anatomy and that of mysticetes in general. Dissection of the head of a neonatal gray whale revealed novel anatomical details of the eye, blowhole, incisive papilla with associated nasopalatine ducts, sensory hairs, and throat grooves. Compared to a similar sized right whale calf, the gray...

The gray whale (Eschrichtius robustus) is the sole living representative of the mysticete (baleen whale) family Eschrichtiidae. Previous anatomical work on gray whales has been limited owing, in part, to difficulties of specimen access. These contributions to the anatomy of the gray whale head based on dissection of a stranded specimen from norther...

Mysticetes have evolved a novel filter feeding apparatus-baleen-an epidermal keratinous tissue composed of keratin that grows as a serial arrangement of transverse cornified laminae from the right and left sides of the palate. The structure and function of baleen varies among extant mysticete clades and this variation likely can be viewed as adapta...

The origin of baleen in mysticetes heralded a major transition during cetacean evolution. Extant mysticetes are edentulous in adulthood, but rudimentary teeth develop in utero within open maxillary and mandibular alveolar grooves. The teeth are resorbed prenatally and the alveolar grooves close as baleen germ develops. Arteries supplying blood to h...

The holotype of Pliophoca etrusca, a partial skeleton from the late Pliocene (Piacenzian) of central Italy, is redescribed. Referred material from the Pliocene of Italy, France, and Spain is compared with the holotype and reassigned to Pliophoca cf. P. etrusca. New dental and postcranial material from the late Pliocene and Pleistocene of Italy is r...

Marine Mammals: Evolutionary Biology, Third Edition is a succinct, yet comprehensive text devoted to the systematics, evolution, morphology, ecology, physiology, and behavior of marine mammals. Earlier editions of this valuable work are considered required reading for all marine biologists concerned with marine mammals, and this text continues that...

The cetacean nose presents a unique suite of anatomical modifications. Key among these is posterior movement of the external nares from the tip of the rostrum to the top of the head. Concomitant with these anatomical changes are functional changes including the evolution of echolocation in odontocetes, and reduction of olfaction in Neoceti (crown o...

High-resolution X-ray computed tomographic scans were used to examine pterygoid sinus morphology within extant porpoise species and one delphinid (Tursiops truncatus), in order to consider: 1) intraspecific and interspecific variation among the studied species; 2) the most parsimonious sequence of character acquisition; and 3) the potential functio...

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be disco...

Toothed whales (crown Odontoceti) are unique among mammals in their ability to echolocate underwater, using specialized tissue structures. The melon, a structure composed of fat and connective tissue, is an important component in the production of an echolocation beam; it is known to focus high frequency, short duration echolocation clicks. Here, w...

Carnivora includes three independent evolutionary transitions to the marine environment: pinnipeds (seals, sea lions, and walruses), sea otters, and polar bears. Among these, only the pinnipeds have retained two forms of insulation, an external fur layer and an internal blubber layer for keeping warm in water. In this study we investigated key fact...

Odontocete mandibles serve multiple functions, including feeding and hearing. We consider that these two major functions have their primary influence in different parts of the mandibles: the anterior feeding component and the posterior sound reception component, though these divisions are not mutually exclusive. One hypothesis is that sound enters...

Balaenidae (right whales) are large, critically endangered baleen whales represented by four living species. The evolutionary relationships of balaenids are poorly known, with the number of genera, relationships to fossil taxa, and position within Mysticeti in contention. This study employs a comprehensive set of morphological characters to address...

Carnivora includes three independent evolutionary transitions to the marine environment: pinnipeds (seals, sea lions, and walruses), sea otters, and polar bears. All three lineages must contend with the thermal challenges of submersion in the marine environment. In the present study, we investigated changes in the fur associated with the transition...

Return to the Sea portrays the life and evolutionary times of marine mammals-from giant whales and sea cows that originated 55 million years ago to the deep diving elephant seals and clam-eating walruses of modern times. This fascinating account of the origin of various marine mammal lineages, some extinct, others extant but threatened, is for the...

This chapter provides an introduction to fossils and a geologic time frame, which provides a context for interpreting marine mammal fossils and possible causes for their origin and diversification. The evolution of marine mammal communities through space and time are considered, as well as what may have led marine mammals back to the sea. The use o...

The origin and evolutionary history of sirenians (manatees and dugongs) and their extinct relatives are reviewed in this chapter, in addition to sea and marine otters, polar bears, and evolutionary dead ends—aquatic sloths and desmostylians. Among structural and functional innovations and adaptations covered are the presence of body hairs and a lat...

The ecologic role of marine mammals is explored in this chapter, including food and the feeding relationships of marine mammals and the effects of change on the dynamics of marine ecosystems. Also considered is the effect of humans on marine mammal communities, ranging from oil spills and contamination of the ocean with heavy metals to diseases and...

The origin and evolutionary history of pinnipeds (seals, sea lions, and walruses) is traced in this chapter. Also covered are their adaptations—major structural and functional innovations such as blubber and fur, flippers and locomotion on land and in the water, and deep-diving physiology. Key aspects of pinniped biology and behavior, including pol...

The origin and evolutionary history of cetartiodactylans, which include cetaceans (whales, dolphins, and porpoises) and their extinct ungulate relatives, is explored in this chapter. The excellent whale fossil record shows how they evolved from a land mammal ancestry. Structural and functional innovations and adaptations such as skin with thick blu...

This chapter is a brief introduction to the diversity of major marine mammal lineages, including their identification, naming, and classification. The process of reconstructing the evolutionary history of marine mammals and forming new species is also discussed. Finally, physical factors such as ocean temperature, depth, salinity, and circulation p...

ABSTRACT1 Pinnipeds are charismatic but difficult to study, and taxonomy is poorly understood. An accurate taxonomic framework is essential for studies of biogeography, ecology and conservation. 2 Morphologic and genetic criteria used to recognize pinniped species and subspecies are evaluated individually for all taxa in the three families: Otariid...

Three most parsimonious trees recovered from phylogenetic analysis of 48 petrotympanic characters. Major difference between topologies lies with Eschrichtius robusts and Megaptera novaeangliae (in bold). (TIFF)

Measurements (mm) of tympani bulla of balaenid and neobalaenid species. (PDF)

Measurements (mm) of tympanic bulla of balaenopterid and eschrichtiid species. (PDF)

Petrosal measurements (mm) among mysticetes and reated taxa. (PDF)

Dichotomous key for identifying extant species of mysticetes using the petrotympanic complex. (PDF)

Six most parsimonious trees recovered from phylogenetic analysis of petrotympanic characters excluding #45 (location of hiatus Fallopii). (TIFF)

List of extant mysticetes studied (institutional abbreviations in text). (PDF)

Tympanic bulla anterior lobe measurements (mm) among mysticetes. (PDF)

Tympanic bulla conical process measurements (mm) among mysticetes. (PDF)

Data matrix of petrotrympanic characters scored for extant mysticetes used in phylogeneti analyses. Matrix can be downloaded from project page associated with this manuscript at MorphoBank (www.morphobank.org). (PDF)

Phylogenetic characters derived from the petrotympanic complex of extant mysticetes. Further information can be found on the project page associated with this study at MorphoBank (www.morphobank.org). (PDF)

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, includ...

The bones of the posterior portion of the mammalian skull often exhibit incomplete ossification of the joints between the bones at the time of birth, with complete ossification at some point after birth. The sequence of ossification of these joints in mysticetes can be used to characterize the relative age in the calf and early juvenile ontogenetic...

All extant members of Phocoenidae (porpoises) have been characterized as pedomorphic based on skeletal characters. To investigate the ontogenetic background for pedomorphosis and assess interspecific differences in ontogeny among phocoenids, samples of the six extant species were compared in terms of development of both epiphyseal and cranial sutur...

Some odontocetes possess unique features of the hyolingual apparatus that are involved in suction feeding. The hyoid bone and associated musculature generates rapid, piston-like retraction, and depression of the hyoid and tongue. “Capture” suction feeders (e.g., Globicephala) use suction for capturing and swallowing prey. “Combination” feeders (i.e...

Previous studies of the odontocete forelimb have not considered flipper anatomy in an evolutionary context. This study of 39 cetacean species (1 extinct archaeocete, 31 extant and 3 extinct odontocetes, and 4 mysticetes), provides a detailed comparative analysis of the major bones and muscles of the odontocete flipper. Differences across families i...

Lipoprotein lipase activity and its relationship to high milk fat transfer during lactation in grey seals .. Individual varia-tion in milk composition over lactation in harbour seals (Phoca vitu-lina) and the potential consequences of intermittent attendance . Can.. Fat transfer and energetics during lactation in the hooded seal: the roles of tissu...

The name Pinnipedia was first proposed for fin-footed carnivores more than a century ago. Pinnipeds-fur seals and sea lions, walruses and seals-are one of three major clades of modern marine mammals, having a fossil record going back at least to the late Oligocene. There has long been a debate about the relationship of pinnipeds to one another and...

The fossil record of mysticete cetaceans is rapidly improving and the origin and diversification of this highly specialized mammalian group is coming into focus. Crown mysticetes are edentulous as adults, but possess deciduous teeth that are resorbed prior to birth. This ontogenetic pattern reflects an ancestral ontogeny in which fully formed teeth...

This chapter discusses systematics, which is the study of biological diversity that has as its primary goal the reconstruction of phylogeny, the evolutionary or genealogical history of particular groups of organisms. Because of its emphasis on phylogeny, this discipline is often referred to as phylogenetic systematics or cladistics. The rapid pace...

Previous hypotheses for the origin and diversification of pinnipeds have followed a narrative approach based mostly on dispersalist (i.e., center of origin) explanations. Using an analytical approach, we present a testable hypothesis to explain the evolutionary biogeography of pinnipedimorphs (fur seals, sea lions, walruses, seals, and their fossil...

1 Biology Department, San Diego State University, San Diego, California 92182, U.S.A. E-mail: Cassie.Johnston1@gmail.com [Correction added after publication online: change in corresponding author's email address.]

Toothed mysticetes of the family Aetiocetidae from Oligocene rocks of the North Pacific play a key role in interpretations of cetacean evolution because they are transitional in grade between dorudontine archaeocetes and edentulous mysticetes. The holotype skull of Aetiocetus weltoni from the late Oligocene (28–24 Ma) of Oregon, USA, has been furth...

In air-borne hearing, mammals rely on sound transmission through the tympanic membrane and middle ear ossicles between the surrounding air and the cochlea. The high-frequency hearing limit (HFHL) is determined by the ossicular inertia, and also by the cochlear sensitivity. Due to coevolution, the sensitivity ranges of the middle and inner ear struc...