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https://www.readbyqxmd.com/read/28726248/finding-sacral-developmental-evolution-of-the-axial-skeleton-of-odontocetes-cetacea
#1
Emily A Buchholtz, Jessica K Gee
Axial morphology was dramatically transformed during the transition from terrestrial to aquatic environments by archaeocete cetaceans, and again during the subsequent odontocete radiation. Here, we reconstruct the sequence of developmental events that underlie these phenotypic transitions. Archaeocete innovations include the loss of primaxial/abaxial interaction at the sacral/pelvic articulation and the modular dissociation of the fluke from the remainder of the tail. Odontocetes subsequently integrated lumbar, sacral, and anterior caudal vertebrae into a single torso module, and underwent multiple series-specific changes in vertebral count...
July 20, 2017: Evolution & Development
https://www.readbyqxmd.com/read/28573006/a-new-fossil-dolphin-dilophodelphis-fordycei-provides-insight-into-the-evolution-of-supraorbital-crests-in-platanistoidea-mammalia-cetacea
#2
Alexandra T Boersma, Matthew R McCurry, Nicholas D Pyenson
Many odontocete groups have developed enlarged facial crests, although these crests differ in topography, composition and function. The most elaborate crests occur in the South Asian river dolphin (Platanista gangetica), in which they rise dorsally as delicate, pneumatized wings anterior of the facial bones. Their position wrapping around the melon suggests their involvement in sound propagation for echolocation. To better understand the origin of crests in this lineage, we examined facial crests among fossil and living Platanistoidea, including a new taxon, Dilophodelphis fordycei, nov...
May 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28333389/the-cochlea-of-the-enigmatic-pygmy-right-whale-caperea-marginata-informs-mysticete-phylogeny
#3
Travis Park, Felix G Marx, Erich M G Fitzgerald, Alistair R Evans
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...
June 2017: Journal of Morphology
https://www.readbyqxmd.com/read/28293739/a-new-synthesium-species-digenea-brachycladiidae-from-the-bottlenose-dolphin-tursiops-truncatus-cetacea-delphinidae-in-southwestern-atlantic-waters
#4
Mariana B Ebert, Maria I Mülller, Juliana Marigo, Ana L S Valente, Marta J Cremer, Reinaldo J da Silva
A new species of Synthesium from the bottlenose dolphin Tursiops truncatus in South Brazilian waters is described. Morphological and molecular identification was performed, and phylogenetic analyses were carried out using the ribosomal small subunit and internal transcribed spacer 1 and the mitochondrial NDH dehydrogenase subunit 3 and cytochrome c oxidase subunit 1 genes. The main characteristics of the new species are the subterminal round-shaped oral sucker, the anterior distribution of vitellaria reaching the level of the ovary and the oval-shaped testes...
May 2017: Parasitology Research
https://www.readbyqxmd.com/read/28257606/morphology-and-ultrastructure-of-the-amazon-river-dolphin-inia-geoffrensis-spermatozoa
#5
Rodrigo S Amaral, Vera M F DA Silva, Fabíola X Valdez Domingos, Anthony R Martin
The spermatozoa from seven adult Amazon river dolphins (Inia geoffrensis, CETACEA: INIIDAE) were analyzed by light and electron microscopy. The spermatozoa showed an elongated ellipsoid shaped head and a long tail with a well distinguishable midpiece. The head spermatozoa have a smooth surface like other odontocetes examined, with the exception of the Delphinidae family. The mean dimensions of the spermatozoa were within the range already reported for other cetaceans. The spermatozoa midpiece, as in other cetaceans, showed a random pattern of mitochondria, different from that described for other mammals...
March 3, 2017: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
https://www.readbyqxmd.com/read/28250185/epistatic-interactions-influence-terrestrial-marine-functional-shifts-in-cetacean-rhodopsin
#6
Sarah Z Dungan, Belinda S W Chang
Like many aquatic vertebrates, whales have blue-shifting spectral tuning substitutions in the dim-light visual pigment, rhodopsin, that are thought to increase photosensitivity in underwater environments. We have discovered that known spectral tuning substitutions also have surprising epistatic effects on another function of rhodopsin, the kinetic rates associated with light-activated intermediates. By using absorbance spectroscopy and fluorescence-based retinal release assays on heterologously expressed rhodopsin, we assessed both spectral and kinetic differences between cetaceans (killer whale) and terrestrial outgroups (hippo, bovine)...
March 15, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28193458/inactivation-of-the-olfactory-marker-protein-omp-gene-in-river-dolphins-and-other-odontocete-cetaceans
#7
Mark S Springer, John Gatesy
Various toothed whales (Odontoceti) are unique among mammals in lacking olfactory bulbs as adults and are thought to be anosmic (lacking the olfactory sense). At the molecular level, toothed whales have high percentages of pseudogenic olfactory receptor genes, but species that have been investigated to date retain an intact copy of the olfactory marker protein gene (OMP), which is highly expressed in olfactory receptor neurons and may regulate the temporal resolution of olfactory responses. One hypothesis for the retention of intact OMP in diverse odontocete lineages is that this gene is pleiotropic with additional functions that are unrelated to olfaction...
February 11, 2017: Molecular Phylogenetics and Evolution
https://www.readbyqxmd.com/read/27764133/intra-and-interspecific-interactions-as-proximate-determinants-of-sexual-dimorphism-and-allometric-trajectories-in-the-bottlenose-dolphin-tursiops-truncatus-cetacea-odontoceti-delphinidae
#8
Maria Carla de Francesco, Anna Loy
Feeding adaptation, social behaviour, and interspecific interactions related to sexual dimorphism and allometric growth are particularly challenging to be investigated in the high sexual monomorphic Delphinidae. We used geometric morphometrics to extensively explore sexual dimorphism and ontogenetic allometry of different projections of the skull and the mandible of the bottlenose dolphin Tursiops truncatus. Two-dimensional landmarks were recorded on the dorsal, ventral, lateral, and occipital views of the skull, and on the lateral view of the left and the right mandible of 104 specimens from the Mediterranean and the North Seas, differing environmental condition and degree of interspecific associations...
2016: PloS One
https://www.readbyqxmd.com/read/27706394/variation-of-age-and-total-length-in-sotalia-guianensis-van-b%C3%A3-n%C3%A3-den-1864-cetacea-delphinidae-on-the-coast-of-esp%C3%A3-rito-santo-state-brazil
#9
J Y Lima, A P M Carvalho, C T Azevedo, L A Barbosa, L S Silveira
Variations of age and total length of Sotalia guianensis from the state of Espírito Santo, Brazil, were evaluated. Specimens were found stranded. Age and total length of 44 Guiana dolphins were assessed based on tooth analysis. Age varied between 0.5 year and 33 years (mean = 8.23 years). Most specimens were between zero and 6 years old (47%). Total length varied from 119 cm to 198 cm, with mean of 172.52 cm. Asymptotic length was reached at 185 cm and approximately 5-6 years of age. Mean total length and age were higher than in other regions of the distribution range of the species...
October 3, 2016: Brazilian Journal of Biology, Revista Brasleira de Biologia
https://www.readbyqxmd.com/read/27688973/new-beaked-whales-from-the-late-miocene-of-peru-and-evidence-for-convergent-evolution-in-stem-and-crown-ziphiidae-cetacea-odontoceti
#10
Giovanni Bianucci, Claudio Di Celma, Mario Urbina, Olivier Lambert
The Ziphiidae (beaked whales) represent a large group of open-ocean odontocetes (toothed cetaceans), whose elusive and deep diving behavior prevents direct observation in their natural habitat. Despite their generally large body size, broad geographical distribution, and high species number, ziphiids thus remain poorly known. Furthermore, the evolutionary processes that have led to their extreme adaptations and impressive extant diversity are still poorly understood. Here we report new fossil beaked whales from the late Miocene of the Pisco Formation (southern Peru)...
2016: PeerJ
https://www.readbyqxmd.com/read/27627739/morphological-variation-among-the-inner-ears-of-extinct-and-extant-baleen-whales-cetacea-mysticeti
#11
Eric G Ekdale
Living mysticetes (baleen whales) and odontocetes (toothed whales) differ significantly in auditory function in that toothed whales are sensitive to high-frequency and ultrasonic sound vibrations and mysticetes to low-frequency and infrasonic noises. Our knowledge of the evolution and phylogeny of cetaceans, and mysticetes in particular, is at a point at which we can explore morphological and physiological changes within the baleen whale inner ear. Traditional comparative anatomy and landmark-based 3D-geometric morphometric analyses were performed to investigate the anatomical diversity of the inner ears of extinct and extant mysticetes in comparison with other cetaceans...
December 2016: Journal of Morphology
https://www.readbyqxmd.com/read/27615844/the-whale-barnacle-cryptolepas-rhachianecti-cirripedia-coronulidae-a-phoront-of-the-grey-whale-eschrichtius-robustus-cetacea-eschrichtiidae-from-a-sandy-beach-in-the-netherlands
#12
Mark Bosselaers, Alberto Collareta
An isolated compartment of a whale barnacle is herein described from Recent beach deposits in Zoutelande (Walcheren, The Netherlands). This specimen is identified as belonging to the extant coronulid species Cryptolepas rhachianecti, currently known as an epizoic symbiont of the grey whale Eschrichtius robustus. This find represents the first occurrence of C. rhachianecti outside the North Pacific, and the first one as a (sub)fossil. In view of the fact that E. robustus, which is currently confined to the North Pacific, is known as a subfossil from the northeastern Atlantic between late Late Pleistocene (c...
August 22, 2016: Zootaxa
https://www.readbyqxmd.com/read/27602287/arktocara-yakataga-a-new-fossil-odontocete-mammalia-cetacea-from-the-oligocene-of-alaska-and-the-antiquity-of-platanistoidea
#13
Alexandra T Boersma, Nicholas D Pyenson
The diversification of crown cetacean lineages (i.e., crown Odontoceti and crown Mysticeti) occurred throughout the Oligocene, but it remains an ongoing challenge to resolve the phylogenetic pattern of their origins, especially with respect to stem lineages. One extant monotypic lineage, Platanista gangetica (the Ganges and Indus river dolphin), is the sole surviving member of the broader group Platanistoidea, with many fossil relatives that range from Oligocene to Miocene in age. Curiously, the highly threatened Platanista is restricted today to freshwater river systems of South Asia, yet nearly all fossil platanistoids are known globally from marine rocks, suggesting a marine ancestry for this group...
2016: PeerJ
https://www.readbyqxmd.com/read/27446905/an-ltr-retrotransposon-derived-gene-displays-lineage-specific-structural-and-putative-species-specific-functional-variations-in-eutherians
#14
Masahito Irie, Akihiko Koga, Tomoko Kaneko-Ishino, Fumitoshi Ishino
Amongst the 11 eutherian-specific genes acquired from a sushi-ichi retrotransposon is the CCHC type zinc-finger protein-encoding gene SIRH11/ZCCHC16. Its contribution to eutherian brain evolution is implied because of its involvement in cognitive function in mice, possibly via the noradrenergic system. Although, the possibility that Sirh11/Zcchc16 functions as a non-coding RNA still remains, dN/dS ratios in pairwise comparisons between its orthologs have provided supportive evidence that it acts as a protein...
2016: Frontiers in Chemistry
https://www.readbyqxmd.com/read/27418018/structure-and-growth-pattern-of-the-bizarre-hemispheric-prominence-on-the-rostrum-of-the-fossil-beaked-whale-globicetus-hiberus-mammalia-cetacea-ziphiidae
#15
Maïtena Dumont, Vivian de Buffrénil, Ismael Miján, Olivier Lambert
The rostrum of most ziphiids (beaked whales) displays bizarre swollen regions, accompanied with extreme hypermineralisation and an alteration of the collagenous mesh of the bone. The functional significance of this specialization remains obscure. With the voluminous and dense hemispheric excrescence protruding from the premaxillae, the recently described fossil ziphiid Globicetus hiberus is the most spectacular case. This study describes the histological structure and interprets the growth pattern of this unique feature...
October 2016: Journal of Morphology
https://www.readbyqxmd.com/read/27366197/dietary-specialization-drives-multiple-independent-losses-and-gains-in-the-bitter-taste-gene-repertoire-of-laurasiatherian-mammals
#16
Zhijin Liu, Guangjian Liu, Frank Hailer, Pablo Orozco-terWengel, Xinxin Tan, Jundong Tian, Zhongze Yan, Baowei Zhang, Ming Li
BACKGROUND: Bitter taste perception is essential for species with selective food intake, enabling them to avoid unpalatable or toxic items. Previous studies noted a marked variation in the number of TAS2R genes among various vertebrate species, but the underlying causes are not well understood. Laurasiatherian mammals have highly diversified dietary niche, showing repeated evolution of specialized feeding preferences in multiple lineages and offering a unique chance to investigate how various feeding niches are associated with copy number variation for bitter taste receptor genes...
2016: Frontiers in Zoology
https://www.readbyqxmd.com/read/27336480/back-to-water-signature-of-adaptive-evolution-in-cetacean-mitochondrial-trnas
#17
Stefano Montelli, Antonella Peruffo, Tomaso Patarnello, Bruno Cozzi, Enrico Negrisolo
The mitochondrion is the power plant of the eukaryotic cell, and tRNAs are the fundamental components of its translational machinery. In the present paper, the evolution of mitochondrial tRNAs was investigated in the Cetacea, a clade of Cetartiodactyla that retuned to water and thus had to adapt its metabolism to a different medium than that of its mainland ancestors. Our analysis focussed on identifying the factors that influenced the evolution of Cetacea tRNA double-helix elements, which play a pivotal role in the formation of the secondary and tertiary structures of each tRNA and consequently manipulate the whole translation machinery of the mitochondrion...
2016: PloS One
https://www.readbyqxmd.com/read/27119362/neuroanatomy-of-the-killer-whale-orcinus-orca-a-magnetic-resonance-imaging-investigation-of-structure-with-insights-on-function-and-evolution
#18
Alexandra Wright, Miriam Scadeng, Dominik Stec, Rebecca Dubowitz, Sam Ridgway, Judy St Leger
The evolutionary process of adaptation to an obligatory aquatic existence dramatically modified cetacean brain structure and function. The brain of the killer whale (Orcinus orca) may be the largest of all taxa supporting a panoply of cognitive, sensory, and sensorimotor abilities. Despite this, examination of the O. orca brain has been limited in scope resulting in significant deficits in knowledge concerning its structure and function. The present study aims to describe the neural organization and potential function of the O...
April 27, 2016: Brain Structure & Function
https://www.readbyqxmd.com/read/27088853/comparative-chromosome-map-and-heterochromatin-features-of-the-gray-whale-karyotype-cetacea
#19
COMPARATIVE STUDY
Anastasia I Kulemzina, Anastasia A Proskuryakova, Violetta R Beklemisheva, Natalia A Lemskaya, Polina L Perelman, Alexander S Graphodatsky
Cetacean karyotypes possess exceptionally stable diploid numbers and highly conserved chromosomes. To date, only toothed whales (Odontoceti) have been analyzed by comparative chromosome painting. Here, we studied the karyotype of a representative of baleen whales, the gray whale (Eschrichtius robustus, Mysticeti), by Zoo-FISH with dromedary camel and human chromosome-specific probes. We confirmed a high degree of karyotype conservation and found an identical order of syntenic segments in both branches of cetaceans...
2016: Cytogenetic and Genome Research
https://www.readbyqxmd.com/read/27087919/hybridization-in-the-cetacea-widespread-occurrence-and-associated-morphological-behavioral-and-ecological-factors
#20
Carla A Crossman, Eric B Taylor, Lance G Barrett-Lennard
Hybridization has been documented in a many different pairs of cetacean species both in captivity and in the wild. The widespread occurrence of hybridization indicates that postmating barriers to interbreeding are incomplete within the order Cetacea, and therefore raises questions about how species integrity is maintained in the face of interspecific (and often intergeneric) gene flow. We examined hybridization across the order Cetacea (oceanic species included: N = 78; species with 44 chromosomes included: N = 52) to test for associations between the occurrence of hybridization and similarity across 13 ecological, morphological and behavioral traits in hybridizing vs...
March 2016: Ecology and Evolution
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