ORCID Profile
0000-0002-9492-8859
Current Organisation
Monash University
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Evolutionary Impacts of Climate Change | Phylogeny and Comparative Analysis | Evolutionary Biology | Biological Adaptation
Expanding Knowledge in the Earth Sciences | Expanding Knowledge in the Biological Sciences | Marine Flora, Fauna and Biodiversity |
Publisher: Springer Science and Business Media LLC
Date: 24-10-2019
DOI: 10.1186/S12862-019-1525-X
Abstract: Odontocetes (toothed whales) are the most species-rich marine mammal lineage. The catalyst for their evolutionary success is echolocation - a form of biological sonar that uses high-frequency sound, produced in the forehead and ultimately detected by the cochlea. The ubiquity of echolocation in odontocetes across a wide range of physical and acoustic environments suggests that convergent evolution of cochlear shape is likely to have occurred. To test this, we used SURFACE a method that fits Ornstein-Uhlenbeck (OU) models with stepwise AIC (Akaike Information Criterion) to identify convergent regimes on the odontocete phylogeny, and then tested whether convergence in these regimes was significantly greater than expected by chance. We identified three convergent regimes: (1) True’s ( Mesoplodon mirus ) and Cuvier’s ( Ziphius cavirostris ) beaked whales (2) sperm whales ( Physeter macrocephalus ) and all other beaked whales s led and (3) pygmy ( Kogia breviceps ) and dwarf ( Kogia sima ) sperm whales and Dall’s porpoise ( Phocoenoides dalli ). Interestingly the ‘river dolphins’, a group notorious for their convergent morphologies and riverine ecologies, do not have convergent cochlear shapes. The first two regimes were significantly convergent, with habitat type and e type significantly correlated with membership of the sperm whale + beaked whale regime. The extreme acoustic environment of the deep ocean likely constrains cochlear shape, causing the cochlear morphology of sperm and beaked whales to converge. This study adds support for cochlear morphology being used to predict the ecology of extinct cetaceans.
Publisher: PeerJ
Date: 22-06-2018
DOI: 10.7717/PEERJ.5025
Abstract: 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 ergence 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.
Publisher: Springer Science and Business Media LLC
Date: 21-05-2018
Publisher: Authorea, Inc.
Date: 2014
Publisher: PeerJ
Date: 13-04-2020
DOI: 10.7717/PEERJ.8916
Abstract: In morphological traits, variation within species is generally considered to be lower than variation among species, although this assumption is rarely tested. This is particularly important in fields like palaeontology, where it is common to use a single in idual as representative of a species due to the rarity of fossils. Here, we investigated intraspecific variation in the cochleae of harbour porpoises ( Phocoena phocoena ). Interspecific variation of cochlear morphology is well characterised among odontocetes (toothed whales) because of the importance of the structure in echolocation, but generally these studies use only a single cochlea to represent each species. In this study we compare variation within the cochleae of 18 specimens of P. phocoena with variations in cochlear morphology across 51 other odontocete species. Using both 3D landmark and linear measurement data, we performed Generalised Procrustes and principal component analyses to quantify shape variation. We then quantified intraspecific variation in our s le of P. phocoena by estimating disparity and the coefficient of variation for our 3D and linear data respectively. Finally, to determine whether intraspecific variation may confound the results of studies of interspecific variation, we used multivariate and univariate analyses of variance to test whether variation within the specimens of P. phocoena was significantly lower than that across odontocetes. We found low levels of intraspecific variation in the cochleae of P. phocoena , and that cochlear shape within P. phocoena was significantly less variable than across odontocetes. Although future studies should attempt to use multiple cochleae for every species, our results suggest that using just one cochlea for each species should not strongly influence the conclusions of comparative studies if our results are consistent across Cetacea.
Publisher: The Royal Society
Date: 03-2017
Abstract: Extant aquatic mammals are a key component of aquatic ecosystems. Their morphology, ecological role and behaviour are, to a large extent, shaped by their feeding ecology. Nevertheless, the nature of this crucial aspect of their biology is often oversimplified and, consequently, misinterpreted. Here, we introduce a new framework that categorizes the feeding cycle of predatory aquatic mammals into four distinct functional stages (prey capture, manipulation and processing, water removal and swallowing), and details the feeding behaviours that can be employed at each stage. Based on this comprehensive scheme, we propose that the feeding strategies of living aquatic mammals form an evolutionary sequence that recalls the land-to-water transition of their ancestors. Our new conception helps to explain and predict the origin of particular feeding styles, such as baleen-assisted filter feeding in whales and raptorial ‘pierce’ feeding in pinnipeds, and informs the structure of present and past ecosystems.
Publisher: Wiley
Date: 31-01-2020
DOI: 10.1111/MMS.12666
Publisher: Springer Science and Business Media LLC
Date: 08-2017
Publisher: Museums Victoria
Date: 2012
Publisher: Cold Spring Harbor Laboratory
Date: 09-09-2022
DOI: 10.1101/2022.09.07.506945
Abstract: Adaptive landscapes are central to evolutionary theory, forming a conceptual bridge between micro- and macro-evolution 1–4 . Evolution by natural selection across an adaptive landscape should drive lineages towards fitness peaks, shaping the distribution of phenotypic variation within and among clades over evolutionary timescales 5 . Constant shifts in selection pressures mean the peaks themselves also evolve through time 4 , thus a key challenge is to identify these ‘ghosts of selection past’. Here, we characterise the global and local adaptive landscape for total length in cetaceans (whales and dolphins) across their ~ 53 million year evolutionary history, using 345 living and fossil taxa. We analyse shifts in long-term mean size 6 and directional changes in average trait values 7 using cutting-edge phylogenetic comparative methods. We demonstrate that the global macroevolutionary adaptive landscape of cetacean body size is relatively flat, with very few peak shifts after cetaceans colonised the oceans. Local peaks represent trends along branches linked to specific adaptations such as deep ing. These results contrast with previous studies using only extant taxa 8 , highlighting the vital role of fossil data for understanding macroevolutionary dynamics. Our results indicate that adaptive peaks are constantly changing and are associated with subzones of local adaptations, resembling turbulent waters with waves and ripples, creating moving targets for species adaptation. In addition, we identify limits in our ability to detect some evolutionary patterns and processes, and suggest multiple approaches are required to characterise complex hierarchical patterns of adaptation in deep-time.
Publisher: Elsevier BV
Date: 05-2023
Publisher: The Royal Society
Date: 04-2016
Abstract: 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 ersification 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 erging 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.
Publisher: Public Library of Science (PLoS)
Date: 26-04-2016
Publisher: Elsevier BV
Date: 05-2022
DOI: 10.1016/J.CUB.2022.04.060
Abstract: The evolution of cetaceans (whales and dolphins) represents one of the most extreme adaptive transitions known, from terrestrial mammals to a highly specialized aquatic radiation that includes the largest animals alive today. Many anatomical shifts in this transition involve the feeding, respiratory, and sensory structures of the cranium, which we quantified with a high-density, three-dimensional geometric morphometric analysis of 201 living and extinct cetacean species spanning the entirety of their ∼50-million-year evolutionary history. Our analyses demonstrate that cetacean suborders occupy distinct areas of cranial morphospace, with extinct, transitional taxa bridging the gap between archaeocetes (stem whales) and modern mysticetes (baleen whales) and odontocetes (toothed whales). This ersity was obtained through three key periods of rapid evolution: first, the initial evolution of archaeocetes in the early to mid-Eocene produced the highest evolutionary rates seen in cetaceans, concentrated in the maxilla, frontal, premaxilla, and nasal second, the late Eocene ergence of the mysticetes and odontocetes drives a second peak in rates, with high rates and disparity sustained through the Oligocene and third, the ersification of odontocetes, particularly sperm whales, in the Miocene (∼18-10 Mya) propels a final peak in the tempo of cetacean morphological evolution. Archaeocetes show the fastest evolutionary rates but the lowest disparity. Odontocetes exhibit the highest disparity, while mysticetes evolve at the slowest pace, particularly in the Neogene. Diet and echolocation have the strongest influence on cranial morphology, with habitat, size, dentition, and feeding method also significant factors impacting shape, disparity, and the pace of cetacean cranial evolution.
Publisher: Informa UK Limited
Date: 15-05-2014
Publisher: The Royal Society
Date: 27-09-2017
Publisher: Informa UK Limited
Date: 09-2012
Publisher: Springer Science and Business Media LLC
Date: 23-01-2023
Publisher: Springer Science and Business Media LLC
Date: 10-07-2020
DOI: 10.1186/S12915-020-00805-4
Abstract: Unlike most mammals, toothed whale (Odontoceti) skulls lack symmetry in the nasal and facial (nasofacial) region. This asymmetry is hypothesised to relate to echolocation, which may have evolved in the earliest erging odontocetes. Early cetaceans (whales, dolphins, and porpoises) such as archaeocetes, namely the protocetids and basilosaurids, have asymmetric rostra, but it is unclear when nasofacial asymmetry evolved during the transition from archaeocetes to modern whales. We used three-dimensional geometric morphometrics and phylogenetic comparative methods to reconstruct the evolution of asymmetry in the skulls of 162 living and extinct cetaceans over 50 million years. In archaeocetes, we found asymmetry is prevalent in the rostrum and also in the squamosal, jugal, and orbit, possibly reflecting preservational deformation. Asymmetry in odontocetes is predominant in the nasofacial region. Mysticetes (baleen whales) show symmetry similar to terrestrial artiodactyls such as bovines. The first significant shift in asymmetry occurred in the stem odontocete family Xenorophidae during the Early Oligocene. Further increases in asymmetry occur in the physeteroids in the Late Oligocene, Squalodelphinidae and Platanistidae in the Late Oligocene/Early Miocene, and in the Monodontidae in the Late Miocene/Early Pliocene. Additional episodes of rapid change in odontocete skull asymmetry were found in the Mid-Late Oligocene, a period of rapid evolution and ersification. No high-probability increases or jumps in asymmetry were found in mysticetes or archaeocetes. Unexpectedly, no increases in asymmetry were recovered within the highly asymmetric ziphiids, which may result from the extreme, asymmetric shape of premaxillary crests in these taxa not being captured by landmarks alone. Early ancestors of living whales had little cranial asymmetry and likely were not able to echolocate. Archaeocetes display high levels of asymmetry in the rostrum, potentially related to directional hearing, which is lost in early neocetes—the taxon including the most recent common ancestor of living cetaceans. Nasofacial asymmetry becomes a significant feature of Odontoceti skulls in the Early Oligocene, reaching its highest levels in extant taxa. Separate evolutionary regimes are reconstructed for odontocetes living in acoustically complex environments, suggesting that these niches impose strong selective pressure on echolocation ability and thus increased cranial asymmetry.
Publisher: Wiley
Date: 23-03-2017
DOI: 10.1002/JMOR.20674
Abstract: 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 s le of the cetotheriid Herpetocetus demonstrates that the presence of a tympanal recess can be variable at the specific and possibly even the intraspecific level.
Publisher: Oxford University Press (OUP)
Date: 10-05-2021
DOI: 10.1093/BIOLINNEAN/BLAB054
Abstract: Cetaceans (whales and dolphins) have some of the largest and most complex brains in the animal kingdom. When and why this trait evolved remains controversial, with proposed drivers ranging from echolocation to foraging complexity and high-level sociality. This uncertainty partially reflects a lack of data on extinct baleen whales (mysticetes), which has obscured deep-time patterns of brain size evolution in non-echolocating cetaceans. Building on new measurements from mysticete fossils, we show that the evolution of large brains preceded that of echolocation, and subsequently followed a complex trajectory involving several independent increases (e.g. in rorquals and oceanic dolphins) and decreases (e.g. in right whales and ‘river dolphins’). Echolocating whales show a greater tendency towards large brain size, thus reaffirming cognitive demands associated with sound processing as a plausible driver of cetacean encephalization. Nevertheless, our results suggest that other factors such as sociality were also important.
Publisher: Informa UK Limited
Date: 26-06-2012
Publisher: Cambridge University Press (CUP)
Date: 03-08-2021
DOI: 10.1017/PAB.2021.11
Abstract: The inner ear of the two higher clades of modern cetaceans (Neoceti) is highly adapted for hearing infrasonic (mysticetes) or ultrasonic (odontocetes) frequencies. Within odontocetes, Platanistoidea comprises a single extant riverine representative, Platanista gangetica , and a ersity of mainly extinct marine species from the late Oligocene onward. Recent studies drawing on features including the disparate tympanoperiotic have not yet provided a consensus phylogenetic hypothesis for platanistoids. Further, cochlear morphology and evolutionary patterns have never been reported. Here, we describe for the first time the inner ear morphology of late Oligocene–early Miocene extinct marine platanistoids and their evolutionary patterns. We initially hypothesized that extinct marine platanistoids lacked a specialized inner ear like P. gangetica and thus, their morphology and inferred hearing abilities were more similar to those of pelagic odontocetes. Our results reveal there is no “typical” platanistoid cochlear type, as the group displays a disparate range of cochlear anatomies, but all are consistent with high-frequency hearing. Stem odontocete Prosqualodon australis and platanistoid Otekaikea huata present a tympanal recess in their cochlea, of yet uncertain function in the hearing mechanism in cetaceans. The more basal morphology of Aondelphis talen indicates it had lower high-frequency hearing than other platanistoids. Finally, Platanista has the most derived cochlear morphology, adding to evidence that it is an outlier within the group and consistent with a -Myr-long separation from its sister genus Zarhachis . The evolution of a singular sound production morphology within Platanistidae may have facilitated the survival of Platanista to the present day.
Publisher: The Royal Society
Date: 08-02-2017
Abstract: Living baleen whales (mysticetes) produce and hear the lowest-frequency (infrasonic) sounds among mammals. There is currently debate over whether the ancestor of crown cetaceans (Neoceti) was able to detect low frequencies. However, the lack of information on the most archaic fossil mysticetes has prevented us from determining the earliest evolution of their extreme acoustic biology. Here, we report the first anatomical analyses and frequency range estimation of the inner ear in Oligocene (34–23 Ma) fossils of archaic toothed mysticetes from Australia and the USA. The cochlear anatomy of these small fossil mysticetes resembles basilosaurid archaeocetes, but is also similar to that of today's baleen whales, indicating that even the earliest mysticetes detected low-frequency sounds, and lacked ultrasonic hearing and echolocation. This suggests that, in contrast to recent research, the plesiomorphic hearing condition for Neoceti was low frequency, which was retained by toothed mysticetes, and the high-frequency hearing of odontocetes is derived. Therefore, the low-frequency hearing of baleen whales has remained relatively unchanged over the last approximately 34 Myr, being present before the evolution of other signature mysticete traits, including filter feeding, baleen and giant body size.
Publisher: Unpublished
Date: 2013
Publisher: Elsevier BV
Date: 06-2021
DOI: 10.1016/J.CUB.2021.03.019
Abstract: Modern pinnipeds (true and eared seals) employ two radically different swimming styles, with true seals (phocids) propelling themselves primarily with their hindlimbs, whereas eared seals (otariids) rely on their wing-like foreflippers.
Publisher: Springer International Publishing
Date: 2021
Publisher: PeerJ
Date: 14-10-2019
DOI: 10.7717/PEERJ.7809
Abstract: Mesoplodont beaked whales are one of the most enigmatic mammalian genera. We document a pod of four beaked whales in the Bay of Biscay breaching and tail slapping alongside a large passenger ferry. Photographs of the animals were independently reviewed by experts, and identified as True’s beaked whales ( Mesoplodon mirus ). This is the first conclusive live sighting of these animals in the north-east Atlantic, and adds information to previous sightings that are likely to have been M. mirus. Photographs of an adult male appears to show two supernumerary teeth posterior to the apical mandibular tusks. Whilst analysed museum specimens ( n = 8) did not show evidence of alveoli in this location, there is evidence of vestigial teeth and variable dentition in many beaked whale species. This is the first such record of supernumerary teeth in True’s beaked whales.
Publisher: Springer International Publishing
Date: 2023
Publisher: Informa UK Limited
Date: 20-04-2020
Publisher: Oxford University Press (OUP)
Date: 03-03-2023
DOI: 10.1093/BIOLINNEAN/BLAC128
Abstract: Within delphinoid cetaceans, snout shape is significantly correlated to diet, with long-snouted raptorial-feeding predators preying on smaller and more agile prey than shorter-snouted species. Although there have been several studies into longirostry from a functional perspective there have been no quantitative analyses of spatial variation in skull shape or how the pattern in skull shape morphospace occupation varies between assemblages. Here we analyse the cranial morphological variation of Delphinoidea assemblages. Firstly, we calculate mean and Gi* hotspot statistics of skull shape across the world’s oceans. We find that tropical and subtropical assemblages exhibit higher average measures of longirostry. This pattern is likely caused by differences in the availability of certain prey types in warmer and cooler environments. Secondly, we calculate mean pairwise distance as well as mean nearest taxon distance in functional traits between the members of 119 unique delphinoid assemblages. There was a trend for low latitude assemblages to exhibit greater overdispersion in PC1 (snout length) compared those from high latitudes. Our results suggest that ocean temperature is influential in determining the ersity, range limits and assemblage structure of delphinoid cetaceans.
Publisher: Museums Victoria
Date: 2016
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2017
End Date: 2019
Funder: European Commission
View Funded ActivityStart Date: 2019
End Date: 2026
Funder: Leverhulme Trust
View Funded ActivityStart Date: 2023
End Date: 2026
Funder: Australian Research Council
View Funded ActivityStart Date: 09-2023
End Date: 08-2026
Amount: $397,908.00
Funder: Australian Research Council
View Funded Activity