Pygmy Right Whale Research Articles

Redescription of three fossil baleen whale skulls from the Miocene of Portugal reveals new cetotheriid phylogenetic insights.

Cetotheriidae is a family of baleen whales that went nearly extinct during the Pleistocene (excluding Caperea marginata). For a long time, the Cetotheriidae family has been seen as a problematic clade, but in the past two decades there have been various studies trying to resolve the phylogeny of this group. In 1831, Alexandre Vandelli described three cetotheriid skulls, found during a gold exploration at Adiça beach (Portugal). These specimens constituted the first Portuguese vertebrate fossils ever published in the literature. Another skull was added to the "Vandelli skulls" by Jacinto Pedro Gomes, in 1914, during a survey of the Museu Nacional de História Natural collections without giving information on the origin of this skull. In 1941, Remington Kellogg states that one of the original "Vandelli skulls" is no longer present in the Museu Nacional de História Natural collections. Until today, there is no information on how, or exactly when, the fourth skull and one of the original three "Vandelli skulls" appeared and disappeared, respectively. Since their discovery, all the attempts to describe these specimens were not based on direct observations and no comprehensive phylogenetic analysis have included the three skulls. Here we provide a detailed anatomic description, a new phylogenetic analysis and a palaeoecological reconstruction of these specimens, clarifying their relationships within the Cetotheriidae family and fostering the importance of these historical specimens to the modern comprehension of fossil whale evolution. In addition, our results support that Cephalotropis nectus is a valid species with an emended diagnosis. We also concluded that two specimens belong to a new genus, forming two new fossil species (new combinations).

Stable isotopes infer the diet and habitat of the enigmatic pygmy right whale (Caperea marginata) off southern Australia

In the Southern Hemisphere, baleen whales generally undertake migrations between productive feeding grounds at high latitudes and breeding grounds at lower latitudes. Pygmy right whales (Caperea marginata) (PRW) are the smallest and most enigmatic baleen whale, that likely forgo long-distance migrations, and instead inhabit temperate and subantarctic waters year-round. Previous research has relied on limited data from sighting and stranding records to infer the habitat use and diet of PRWs, however the absence of long-term and consistent data has left uncertainty surrounding these parameters. We utilized bulk stable isotopes of carbon (δ13C) and nitrogen (δ15N) in baleen from Australian PRWs (n = 14) to infer their diet and habitat use. Stable isotope values from 1980–2019 were then matched to remote sensed data from known upwelling regions (where they likely feed) to examine if their dietary patterns are related to changes in food web dynamics. We found that PRWs remained in mid-latitude waters year-round and showed no evidence of feeding in Antarctic waters. Rather, their isotopic record suggests they remain between coastal waters off southern Australia and the Subtropical Convergence, feeding on krill and copepods. Additionally, there was a weak positive relationship between PRW nitrogen stable isotope values and sea surface temperature (SST) from the eastern Great Australian Bight (GAB) and Bonney Upwelling. This suggests seasonal changes in their diet is possibly correlated to oceanographic changes which drive food-web dynamics in these regions. Unlike larger species of baleen whales that migrate further to highly productive waters in the Southern Ocean to meet their energetic demands, the small PRW, who only reach 6.5m, may sustain both feeding and breeding requirements at mid-latitudes. This is the first study to analyze long-term dietary and movement patterns of the PRW, providing an important contribution to our understanding of the species.

A note on a pygmy right whale (Caperea marginata) sighting in the southwestern Pacific Ocean

There are no previously published sightings of pygmy right whales (Caperea marginata) from the southwest Pacific Ocean. This note reports a sighting of 14 pygmy right whales approximately 445km southeast of Christchurch, New Zealand, at 17:30 on 5 January 2001 (46°26’S, 177°18’E). No cow-calf pairs were observed. Although feeding was not directly observed, several animals defecated during the observation period. The faeces were bright red and formed into small red clumps that bobbed at the water’s surface which implies that the whales had recently been feeding in the immediate area. It appears that pygmy right whales may aggregate at the Sub-tropical Convergence during the austral summer and that this area may represent an important feeding ground.

Structure and properties of baleen in the Southern right (Eubalaena australis) and Pygmy right whales (Caperea marginata)

Baleen is a resilient and keratinised filter-feeding structure attached to the maxilla of mysticete whales. It is strong and tough, yet a pliant and resilient material, that withstands extreme pressures in the oral cavity during feeding. We investigated the structure, water content, wettability and mechanical properties of baleen of the Southern right (SRW) and Pygmy right whales (PRW), to understand the effects of hydration on the physical and mechanical properties of baleen. Sixty 25 × 15mm baleen subsamples were prepared from one individual of SRW and PRW. Half were hydrated in circulated natural seawater for 21 days and half were dry. Water content analysis showed that SRW baleen was 21.2% water weight and PRW was 26.1%. Wettability testing indicated that surfaces of both hydrated and dried SRW and PRW baleen were hydrophilic, with hydrated samples of both species having lower contact angle values. For the SRW, the average contact angle of hydrated baleen was 40° ± 13.2 and 73° ± 6 for dried samples. Hydrated PRW baleen had an average contact angle of 44° ± 15.3, which was lower than in dried samples (74° ± 2.9). Three-point bending mechanical tests showed that the average maximum flexural stress of dried SRW (134.1 ± 34.3 MPa) and PRW samples (117.8 ± 22.3 MPa) were significantly higher than those of hydrated SRW (25.7 ± 6.3 MPa) and PRW (19.7 ± 4.8 MPa) baleen. Scanning electron microscope images showed the stratification of the outer cortical layer, with cross-linked keratin fibres observed within and between baleen keratin sheets. Hydrated baleen, as in its natural and functional behaviour, has greater flexibility and strength, attributes necessary for the complex filter feeding mechanism characteristic of whales. Hydration must be considered when addressing the physical and mechanical properties of baleen, especially when using dried museum specimens.

Crossing the equator: a northern occurrence of the pygmy right whale

Here we document the first stranding record of the pygmy right whale in the Northern Hemisphere—on the coast of The Gambia, Africa (NE Atlantic Ocean, around latitude 13° N)—a location in stark contrast to its current distribution exclusively south of the equator. The original specimen is now missing and untraceable, but a photo found in the files of the Marine Mammal Program, Smithsonian Institution shows sufficient diagnostic features that allow it to be taxonomically identified as the pygmy right whale, Caperea marginata, including: small body size; streamlined overall body shape; generally dark skin coloration; arched rostrum along the lateral margin; triangular and narrow rostrum in dorsal view; lack of head callosities; some fringes on the dorsal surface of the tongue; small and relatively posteriorly positioned dorsal fin; and small and dark-colored flipper. On the whole, a stranding of the pygmy right whale in the Northern Hemisphere, although likely to be a chance event, calls for more detailed studies of how climate change and ocean currents affect the evolution and distribution (re-patterning) of marine mammals and, ultimately, the entire marine ecosystem.

A Miocene pygmy right whale fossil from Australia.

Neobalaenines are an enigmatic group of baleen whales represented today by a single living species: the pygmy right whale, Caperea marginata, found only in the Southern Hemisphere. Molecular divergence estimates date the origin of pygmy right whales to 22–26 Ma, yet so far there are only three confirmed fossil occurrences. Here, we describe an isolated periotic from the latest Miocene of Victoria (Australia). The new fossil shows all the hallmarks of Caperea, making it the second-oldest described neobalaenine, and the oldest record of the genus. Overall, the new specimen resembles C. marginata in its external morphology and details of the cochlea, but is more archaic in it having a hypertrophied suprameatal area and a greater number of cochlear turns. The presence of Caperea in Australian waters during the Late Miocene matches the distribution of the living species, and supports a southern origin for pygmy right whales.

Comparative Anatomy of the Larynx in Pinnipeds (Seal, Sea lion, Walrus)

Pinnipeds (e.g., seal, sea lion, walrus) are marine mammals that spend time both in and out of the water. All are able to vocalize in air using the pneumatically driven vocal fold vibrations, a mechanism common to terrestrial mammals. This is no surprise, as their ancestors were once terrestrial mammals. Pinnipeds, however, are also able to vocalize underwater. It is not known how they generate or transmit these sounds. This study explores pinniped laryngeal anatomy in: harbor seal (Phoca vitulina), gray seal (Halichoerus grypus), elephant seal (Mirounga angustirostris), California sea lion (Zalophus californianus), and walrus (Odobenus rosmarus). Comparisons were made with the laryngeal anatomy of several closely related terrestrial species including: dog (Canis familiaris) and black bear (Ursus americanus), and several semiaquatic species including: polar bear (Ursus maritimus), sea otter (Enhydra lutris), river otter (Lontra canadensis), beaver (Castor canadensis), muskrat (Ondatra zibethicus), and hippo (Hippopotamus amphibius). Comparisons were also made to fully aquatic mammals that can vocalize underwater including: manatee (Trichechus manatus), baleen whales (Caperea marginata, Balaena glacialis, Megaptera novaeangliae, Balaenoptera musculus, B. physalus, B. borealis, B. acutorostrata), and over 20 species of toothed whales (including sperm whales, beaked whales, dolphins, and porpoises). Results indicate that the harbor and gray seals have an unremarkable larynx that appears grossly similar to that of most other mammals. Elephant seal, sea lion, and walrus larynges, however, were unusual in having arytenoid cartilages that are extremely large and rounded on their rostral surface. The arytenoids form a valve across approximately half of the laryngeal lumen. Interestingly, this feature also occurs in sea otters. The corniculate and cuneiform cartilages are difficult to detect in the elephant seal, sea lion, and walrus. The epiglottic cartilage is very short in the sea lion and walrus, similar to the manatee, but robust in the elephant seal. The vestibular fold of the elephant seal is very prominent, and appears connected to the arytenoid cartilage. Harbor seal, gray seal, and walrus vocal folds are oriented perpendicular to airflow, as in other terrestrial mammals. Elephant seal and sea lion vocal folds are rotated, compared with other terrestrial mammals, with the ventral attachment located more rostrally. Their vocal folds are thus positioned near the ventral aspect of the larynx. This orientation is similar to those of the hippo, baleen whales, and toothed whales. None of the pinnipeds have vocal folds resembling the smooth sloped vocal folds of the manatee, or the thickened vocal folds of the polar bear. The unusual arytenoid size and vocal fold orientation in some pinnipeds may indicate evolutionary convergence with other underwater laryngeal vocalizers (e.g., hippo, baleen whales). It is unclear whether laryngeal morphologies of elephant seal, sea lion, and walrus are functional adaptations representing autapomorphies (uniquely derived features) of these species. Further work should be directed towards understanding whether laryngeal specializations may relate to variations in underwater sounds or in‐air vocalizations. More pinniped species need to be studied, particularly deep diving seals that are very vocal (e.g., Weddell seal) or fur seals (having external morphology and behaviors very similar to sea lions).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

How whales used to filter: exceptionally preserved baleen in a Miocene cetotheriid.

Baleen is a comb‐like structure that enables mysticete whales to bulk feed on vast quantities of small prey, and ultimately allowed them to become the largest animals on Earth. Because baleen rarely fossilises, extremely little is known about its evolution, structure and function outside the living families. Here we describe, for the first time, the exceptionally preserved baleen apparatus of an entirely extinct mysticete morphotype: the Late Miocene cetotheriid, Piscobalaena nana, from the Pisco Formation of Peru. The baleen plates of P. nana are closely spaced and built around relatively dense, fine tubules, as in the enigmatic pygmy right whale, Caperea marginata. Phosphatisation of the intertubular horn, but not the tubules themselves, suggests in vivo intertubular calcification. The size of the rack matches the distribution of nutrient foramina on the palate, and implies the presence of an unusually large subrostral gap. Overall, the baleen morphology of Piscobalaena likely reflects the interacting effects of size, function and phylogeny, and reveals a previously unknown degree of complexity in modern mysticete feeding evolution.

The cochlea of the enigmatic pygmy right whale Caperea marginata informs mysticete phylogeny.

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 + 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.

A Link No Longer Missing: New Evidence for the Cetotheriid Affinities of Caperea.

The origins of the enigmatic pygmy right whale Caperea marginata, the only living member of its subfamily (Neobalaeninae), are an outstanding mystery of cetacean evolution. Its strikingly disparate morphology sets Caperea apart from all other whales, and has turned it into a wildcard taxon that holds the key to understanding modern baleen whale diversity. Morphological cladistics generally ally this species with right whales, whereas molecular analyses consistently cluster it with rorquals and grey whales (Balaenopteroidea). A recent study potentially resolved this conflict by proposing that Caperea belongs with the otherwise extinct Cetotheriidae, but has been strongly criticised on morphological grounds. Evidence from the neobalaenine fossil record could potentially give direct insights into morphological transitions, but is currently limited to just a single species: the Late Miocene Miocaperea pulchra, from Peru. We show that Miocaperea has a highly unusual morphology of the auditory region, resulting from a–presumably feeding-related–strengthening of the articulation of the hyoid apparatus with the skull. This distinctive arrangement is otherwise only found in the extinct Cetotheriidae, which makes Miocaperea a “missing link” that demonstrates the origin of pygmy right whales from cetotheriids, and confirms the latter’s resurrection from the dead.

Ancestor-descendant relationships in evolution: origin of the extant pygmy right whale, Caperea marginata.

Ancestor-descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, †Miocaperea pulchra, and its sole living relative, the enigmatic pygmy right whale Caperea marginata, the latter represented by both adult and juvenile specimens. †Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR-the first so far identified within baleen whales (Cetacea: Mysticeti). The †Miocaperea-Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium.

Anatomy of a new cetotheriid genus and species from the Miocene of Herentals, Belgium, and the phylogenetic and palaeobiogeographical relationships of Cetotheriidae s.s. (Mammalia, Cetacea, Mysticeti)

Herentalia nigra gen. et sp. nov. is described and compared to other mysticetes. It belongs to Cetotheriidae s.s. and represents one of the best-preserved cetotheriid skulls from the southern border of the North Sea. A comprehensive phylogenetic analysis revealed that it is closely related to Nannocetus and to a Japanese Herpetocetus, suggesting that it belongs to the subfamily Herpetocetinae. The phylogenetic analysis performed tests the recent hypothesis that Caperea marginata belongs to Cetotheriidae. However the present results confirm that the pygmy right whale cannot be considered a member of Cetotheriidae. The phylogenetic analysis was used as the basis for a cladistic palaeobiogeographical analysis of Cetotheriidae that revealed that the family originated in the Pacific basin during the Burdigalian and subsequently underwent a sequence of dispersal and vicariance events that allowed its members to enter other ocean basins. The evolution of Cetotheriidae diversity was punctuated by two distinct phases of species originations (one in the Burdigalian and the other in the Tortonian) that broadly correspond to a massive increase of food availability in the ocean trophic webs.http://zoobank.org/urn:lsid:zoobank.org:pub:DB1647B0-53E9-4014-B31A-F8B063923EB4

Herpetocetus morrowi(Cetacea: Mysticeti), a new species of diminutive baleen whale from the Upper Pliocene (Piacenzian) of California, USA, with observations on the evolution and relationships of the Cetotheriidae

The extinct edentulous mysticete family Cetotheriidae historically has been viewed as a notoriously paraphyletic group, and only recently have rigorous studies been executed to rectify this issue. These problems do not necessarily just stem from lack of phylogenetic analyses, but are in part because of a general lack of complete specimens, poor descriptions of taxa, and long-lived taxonomic instability issues. The fossil mysticete genus Herpetocetus is a poster child of these problems as it is primarily only known from a few relatively incomplete and poorly described specimens. A new species of Herpetocetus from the upper Pliocene of California, Herpetocetus morrowi sp. nov., provides an archetypal model for the genus based on a multitude of well-preserved specimens. These specimens reveal a diminutive mysticete characterized by an elongate rostrum and roughly quadrate cranium. A mosaic of primitive and derived features preserved in this new species underscores its potential value in helping to resolve a number of taxonomic and phylogenetic problems. The occurrence of specimens assignable to juvenile through to mature adult individuals provides a basis for investigating ontogenetic changes. Functional analysis of the unusual craniomandibular anatomy of H. morrowi suggests a limited degree of mandibular gape and an enhanced capacity for longitudinal rotation of the dentary, features that support a hypothesis of suction feeding convergent with that of living grey whales. A phylogenetic analysis provides support for recognition of a redefined and monophyletic Cetotheriidae and Herpetocetinae, and also serves as a basis for evaluating the recent proposal that the pygmy right whale (Caperea marginata) is a living cetothere. Morphological features of Herpetocetus morrowi, including features of the cranium and petrosal, suggest that a number of the purported synapomorphies supporting a Caperea−cetothere grouping are either symplesiomorphies, nonhomologous features, or are highly variable. © 2014 The Linnean Society of London

Disparate Heterochronic Processes in Baleen Whale Evolution

Skulls of living baleen whales show distinctive patterns of heterochronic ontogenetic change with implications for mysticete evolution. Here, three baleen whale species are analysed and considered in a heterochronic context. Landmarks show that, during ontogeny, skull morphology changes significantly in the rorqual Balaenoptera borealis and humpback Megaptera novaeangliae (both Balaenopteridae), while the pygmy right whale Caperea marginata (Cetotheriidae: Neobalaeninae) retains an overall juvenile morphology from foetus to adult. Geometric morphometric analyses show that foetal and adult C. marginata are similar, whereas the balaenopterids are more disparate: foetal M. novaeangliae and B. borealis appear in one group, and adult M. novaeangliae and B. borealis are grouped closely. Heterochrony involves paedomorphosis for Caperea, and peramorphosis for the balaenopterids. Heterochrony might cause limited or released developmental constraints, leading to low taxonomic diversity in the single surviving species of neobalaenine, and higher diversity amongst balaenopterids.

Association between pygmy right whales (Caperea marginata) and areas of high marine productivity off Australia and New Zealand

Opportunistic sightings and strandings of Caperea marginata (n=196) from the vicinity of Australia and New Zealand (1884 to early 2007) were used to relate geographic and temporal patterns to oceanographic and broad-scale climatic variability. Records were not uniformly distributed along the coast and more (69%) were from Australia than New Zealand. Seven coastal whale ‘hotspots’ were identified which accounted for 61% of records with locality data. Half of the hotspot records were from southeast (37) and northwest (20) Tasmania—others each had 9–15 events. Upwelling and/or high zooplankton abundance has been documented near all whale hotspots. Records of C. marginata occurred in all months, with 75% in spring and summer. Inter-annual variability showed broad agreement between increased whale records (usually in spring/summer) and strongly positive ‘Niño 3.4’ during 1980–1995 but not thereafter. Coastal upwelling and productivity increase during climatic phenomena such as El Niño and are likely to be quickly beneficial to plankton-feeding whales such as C. marginata.

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

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.

Pygmy right whale Caperea marginata records from Namibia

All known records of pygmy right whales Caperea marginata in Namibia since 1978 are summarised for the first time, including 12 strandings (live and recently dead animals) and skeletal remains from at least eight more individuals. The majority of strandings and remains were located in the Walvis Bay region, where the coastal topography of the bay and lagoon may be a primary cause for the relatively high incidence of strandings in this area. Strandings appear to occur only during the austral summer, between November and March. All but two of the records for which age is available were juveniles, suggesting that the area offshore of Walvis Bay may function as a seasonal nursery ground and that the inexperience of younger animals may cause them to become ‘entrapped’ in the bay. These data contribute substantially to the limited information on pygmy right whale distribution worldwide and the cetacean fauna of Namibia.

The pygmy right whale Caperea marginata : the last of the cetotheres

The pygmy right whale, Caperea marginata, is the most enigmatic of the living baleen whales (Mysticeti). Its highly disparate morphology and the virtual absence of a described fossil record have made it extremely difficult to place Caperea into a broader evolutionary context, and molecular and morphological studies have frequently contradicted each other as to the origins and phylogenetic relationships of the species. Our study of a wealth of material from New Zealand collections, representing a wide range of ontogenetic stages, has identified several new features previously unreported in Caperea, which suggest that the pygmy right whale may be the last survivor of the supposedly extinct family Cetotheriidae. This hypothesis is corroborated by both morphology-based and total evidence cladistic analyses, including 166 morphological characters and 23 taxa, representing all the living and extinct families of toothless baleen whales. Our results allow us to formally refer Caperea to Cetotheriidae, thus resurrecting the latter from extinction and helping to clarify the origins of a long-problematic living species.

Juvenile morphology: A clue to the origins of the most mysterious of mysticetes?

The origin of the pygmy right whale (Caperea marginata) has long been one of the most vexing conundrums of marine mammal evolution. The extremely disparate skeletal structure of Caperea and a patchy fossil record have left morphology and molecules at odds: whereas most morphological analyses ally Caperea with right whales (Balaenidae), most molecular studies instead suggest a close relationship with rorquals (Balaenopteridae) and grey whales (Eschrichtiidae). The morphological evidence supporting a Caperea-balaenid clade consists of several shared features of the skull and mandible, as traditionally observed in adult individuals. Here, we show that at least two of these features, the ascending process of the maxilla and the coronoid process, arise from substantially different precursors early during ontogeny and therefore likely do not represent genuine synapomorphies. Both of these juvenile morphologies have adult counterparts in the fossil record, thus indicating that the ontogenetic variation in the living species may be a genuine reflection of differing ancestral states. This new evidence contradicts previous morphological hypotheses on the origins of Caperea and may help to reconcile morphological and molecular evidence.

A Late Miocene potential neobalaenine mandible from Argentina sheds light on the origins of the living pygmy right whale

The origins and evolutionary relationships of the pygmy right whale (Caperea marginata), the only living member of the Neobalaeninae, have been the subject of a long-standing debate. This phylogenetic uncertainty is compounded by a limited neobalaenine fossil record. Here, we report a Late Miocene mysticete mandible from Patagonia, Argentina, and provisionally refer it to Neobalaeninae, gen. et sp. indet. The new material represents only the third report of a fossil neobalaenine, and the first fossil occurrence of this lineage in the southwestern Atlantic. It is also the oldest specimen so far reported, thus corroborating the idea of an early divergence time for neobalaenines.