scholarly journals Unique Short-Faced Miocene Seal Discovered in Grytsiv (Ukraine)

Zoodiversity ◽  
2021 ◽  
Vol 55 (2) ◽  
pp. 143-154
Author(s):  
I. A. Koretsky ◽  
S. J. Rahmat
Keyword(s):  
Late Miocene ◽  
Phylogenetic Relationships ◽  
Evolutionary History ◽  
Morphological Analysis ◽  
First Record ◽  
Cranial Morphology ◽  
Sea Otter ◽  
Terrestrial Mammal ◽  
Large Size ◽  
Rostral Portion

Numerous Miocene terrestrial mammal fossils have been discovered at the Grytsiv locality of Ukraine, but this is the first record of a fossil marine mammal at this site. Morphological analysis of the rostral portion of this middle-late Miocene (12.3–11.8 Ma) partial skull suggests that it belongs to the subfamily Phocinae. The small size and cranial morphology of this partial skull is compared with recent and fossil representatives of the extant subfamily Phocinae and the extinct subfamily Devinophocinae. Extinct and modern representatives of the extant subfamilies Cystophorinae and Monachinae were not incorporated in this study due to their extremely large size in comparison to this new find. This newly described skull belonged to a small-sized seal (likely similar in size to the modern sea otter based on the width of the rostrum) with an extremely short rostrum and several other diagnostic characters that differ from all other fossil and extant phocines. Due to the lack of preservation and fragility of fossil seal skulls, less than 20 have been described so far. This new skull is yet another example of an ancestral seal, supporting the suggestion that modern seals have become larger over their evolutionary history. Overall, any cranial information on fossil true seals is extremely important since it allows resolving contentious phylogenetic relationships between extinct and extant representatives of this group.

Additional Dermal Ossifications in the Anuran Skull: Morphological Novelties or Archaic Elements?

2011 ◽  
Vol 4 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Sergei V. Smirnov
Keyword(s):  
Common Ancestor ◽  
The State ◽  
Cranial Morphology ◽  
Anterior Portion ◽  
Bombina Orientalis ◽  
Common Event ◽  
Rostral Portion ◽  
Morphological Novelties ◽  
Dermal Bones

Examination of the cranial morphology in Bombina orientalis (Anura: Discoglossidae) revealed the occurrence of additional dermal bones lying: a) between the nasals and frontoparietals, b) between frontoparietals, and c) on the tectum synoticum behind the frontoparietals. The presence of similar bones as well as extra ossifications lying in the midline in the rostral portion of skull was shown to be a rather common event among anurans. Based on the occurrence of bones with similar topology in crossopterygians and different stegocephalians, it was concluded that extra ossifications sporadically appearing in anurans are more likely to be ancient cranial elements than neomorphs. Additional dermal bones found in the anterior portion of the anuran skull are homologous to the postrostrals of crossopterygians; extra ossifications lying between the frontoparietals correspond to the bones with similar topology sporadically appearing in crossopterygians and stegocephalians; and extra bones situated behind the frontoparietals are homologous to the lateral extrascapulars (postparietals of stegocephalians) and the median extrascapular of crossopterygians. These extra bones were proposed to be inherited from the presumed common ancestor of all Gnathostomes and retained in anurans in the state of latent capacities. The sporadic appearance of these bones in anurans results from the phenotypical realization of these latent capacities.

scholarly journals Mitochondrial phylogeography of baboons (Papiospp.) – Indication for introgressive hybridization?

2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Dietmar Zinner ◽  
Linn F Groeneveld ◽  
Christina Keller ◽  
Christian Roos
Keyword(s):  
Phylogenetic Relationships ◽  
Evolutionary History ◽  
Introgressive Hybridization ◽  
Distinct Species ◽  
Eastern Africa ◽  
East African ◽  
Hamadryas Baboons ◽  
Olive Baboons ◽  
Initial Separation ◽  
Molecular Studies

Abstract Background Baboons of the genus Papio are distributed over wide ranges of Africa and even colonized parts of the Arabian Peninsula. Traditionally, five phenotypically distinct species are recognized, but recent molecular studies were not able to resolve their phylogenetic relationships. Moreover, these studies revealed para- and polyphyletic (hereafter paraphyletic) mitochondrial clades for baboons from eastern Africa, and it was hypothesized that introgressive hybridization might have contributed substantially to their evolutionary history. To further elucidate the phylogenetic relationships among baboons, we extended earlier studies by analysing the complete mitochondrial cytochrome b gene and the 'Brown region' from 67 specimens collected at 53 sites, which represent all species and which cover most of the baboons' range. Results Based on phylogenetic tree reconstructions seven well supported major haplogroups were detected, which reflect geographic populations and discordance between mitochondrial phylogeny and baboon morphology. Our divergence age estimates indicate an initial separation into southern and northern baboon clades 2.09 (1.54–2.71) million years ago (mya). We found deep divergences between haplogroups within several species (~2 mya, northern and southern yellow baboons, western and eastern olive baboons and northern and southern chacma baboons), but also recent divergence ages among species (< 0.7 mya, yellow, olive and hamadryas baboons in eastern Africa). Conclusion Our study confirms earlier findings for eastern Africa, but shows that baboon species from other parts of the continent are also mitochondrially paraphyletic. The phylogenetic patterns suggest a complex evolutionary history with multiple phases of isolation and reconnection of populations. Most likely all these biogeographic events were triggered by multiple cycles of expansion and retreat of savannah biomes during Pleistocene glacial and inter-glacial periods. During contact phases of populations reticulate events (i.e. introgressive hybridization) were highly likely, similar to ongoing hybridization, which is observed between East African baboon populations. Defining the extent of the introgressive hybridization will require further molecular studies that incorporate additional sampling sites and nuclear loci.

Eggs of extinct dwarf island emus retained large size

2021 ◽  
Vol 17 (5) ◽  
pp. 20210012
Author(s):  
Julian P. Hume ◽  
Christian Robertson
Keyword(s):  
Detailed Analysis ◽  
Life Histories ◽  
First Record ◽  
Museum Specimens ◽  
Linear Measurements ◽  
Large Size ◽  
Dromaius Novaehollandiae

Islands off southern Australia once harboured three subspecies of the mainland emu ( Dromaius novaehollandiae ), the smaller Tasmanian emu ( D. n. diemenensis ) and two dwarf emus, King Island emu ( D. n. minor ) and Kangaroo Island emu ( D. n. baudinianus ), which all became extinct rapidly after discovery by human settlers. Little was recorded about their life histories and only a few historical museum specimens exist, including a number of complete eggs from Tasmania and a unique egg from Kangaroo Island. Here, we present a detailed analysis of eggs of dwarf emus, including the first record of an almost complete specimen from King Island. Our results show that despite the reduction in size of all island emus, especially the King Island emu that averaged 44% smaller than mainland birds, the egg remained similar sized in linear measurements, but less in volume and mass, and seemingly had a slightly thinner eggshell. We provide possible reasons why these phenomena occurred.

scholarly journals The largest known cowrie and the iterative evolution of giant cypraeid gastropods

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stefano Dominici ◽  
Mariagabriella Fornasiero ◽  
Luca Giusberti
Keyword(s):  
Species Richness ◽  
Evolutionary History ◽  
Western Europe ◽  
Negative Relationship ◽  
Species Selection ◽  
Biogeographic Patterns ◽  
Large Size ◽  
Northeastern Italy ◽  
History Of ◽  
Iterative Evolution

AbstractBased on the fossil record, we explore the macroevolutionary relationship between species richness and gigantism in cowries (Cypraeidae), the best-studied family of gastropods, with a global diversity distribution that parallels that of tropical corals, mangroves and seagrasses. We introduce Vicetia bizzottoi sp. nov. based on a Priabonian fossil found in northeastern Italy, the largest documented cowrie found so far and the youngest of a lineage of Eocene Gisortiinae species. The Gisortiinae stratigraphic record in western Europe indicates that species selection favoured large size and armouring of the shell. Palaeoecology and per-stage species richness suggest that gigantism occurred in peripheral habitats with respect to diversity hotspots, where smaller species were favoured. The Eocene–Oligocene boundary was marked by a turnover and the Chattian global warming favoured small-sized species of derived clades. Species selection leading to gigantism is further documented in Miocene lineages of Zoila and Umbilia, in the southern hemisphere, two extant genera distributed at the periphery of modern diversity hotspots, suggesting that the negative relationship between size and diversity is a recurring pattern in the evolutionary history of cowries. This palaeontological evidence is projected onto the existing hypotheses that explain analogous biogeographic patterns in various other taxa. Likewise, body size-species richness negative relationship was possibly driven in cowries by physiological, ecological and life history constraints.

scholarly journals Early diversification and permeable species boundaries in the Mediterranean firs

2019 ◽  
Vol 125 (3) ◽  
pp. 495-507 ◽  
Author(s):  
Francisco Balao ◽  
María Teresa Lorenzo ◽  
José Manuel Sánchez-Robles ◽  
Ovidiu Paun ◽  
Juan Luis García-Castaño ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Evolutionary History ◽  
Taxonomic Status ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Early Diversification ◽  
Genome Wide ◽  
History Of ◽  
The Mediterranean ◽  
Independent Species

Abstract Background and Aims Inferring the evolutionary relationships of species and their boundaries is critical in order to understand patterns of diversification and their historical drivers. Despite Abies (Pinaceae) being the second most diverse group of conifers, the evolutionary history of Circum-Mediterranean firs (CMFs) remains under debate. Methods We used restriction site-associated DNA sequencing (RAD-seq) on all proposed CMF taxa to investigate their phylogenetic relationships and taxonomic status. Key Results Based on thousands of genome-wide single nucleotide polymorphisms (SNPs), we present here the first formal test of species delimitation, and the first fully resolved, complete species tree for CMFs. We discovered that all previously recognized taxa in the Mediterranean should be treated as independent species, with the exception of Abies tazaotana and Abies marocana. An unexpectedly early pulse of speciation in the Oligocene–Miocene boundary is here documented for the group, pre-dating previous hypotheses by millions of years, revealing a complex evolutionary history encompassing both ancient and recent gene flow between distant lineages. Conclusions Our phylogenomic results contribute to shed light on conifers’ diversification. Our efforts to resolve the CMF phylogenetic relationships help refine their taxonomy and our knowledge of their evolution.

Phylogenetic relationships of Mesoamerican species of the genus Sciurus (Rodentia: Sciuridae)

Zootaxa ◽  
2007 ◽  
Vol 1525 (1) ◽  
pp. 31-40 ◽  
Author(s):  
FEDERICO VILLALOBOS ◽  
FERNANDO CERVANTES-REZA
Keyword(s):  
Phylogenetic Relationships ◽  
Maximum Parsimony ◽  
Morphological Analysis ◽  
Taxonomic Status ◽  
The Other

The phylogenetic relationships of Sciurus species present in Mesoamerica are addressed using a morphological analysis under Maximum Parsimony. Our results recovered the existence of two clades: one comprising S. aureogaster, S. colliaei, S. variegatoides and Syntheosciurus brochus and the other clade composed by S. richmondi, S. granatensis, S. deppei, S. yucatanensis and Microsciurus alfari. The taxonomic status of the genera Microsciurus and Syntheosciurus is discussed as well the biogeographic implications of these findings.

The first record of fossil penguins from East Antarctica

2012 ◽  
Vol 25 (3) ◽  
pp. 397-408 ◽  
Author(s):  
Piotr Jadwiszczak ◽  
Krzysztof P. Krajewski ◽  
Zinaida Pushina ◽  
Andrzej Tatur ◽  
Grzegorz Zieliński
Keyword(s):  
Late Miocene ◽  
Middle Miocene ◽  
First Record ◽  
East Antarctica ◽  
X Ray Diffraction ◽  
Diagenetic Alteration ◽  
Strontium Isotope Stratigraphy ◽  
Extant Genus ◽  
Isotope Stratigraphy ◽  
The Antarctic

AbstractThis paper presents the first fossil penguin from East Antarctica, and the only one known south of the Antarctic Circle. It is represented by two well-preserved elements of the wing skeleton, humerus and radius, obviously assignable to the extant genus Spheniscus. They were found in the glaciomarine succession of the Fisher Bench Formation (Fisher Massif, Prince Charles Mountains, Mac. Robertson Land), which was dated using Strontium Isotope Stratigraphy to be Late Miocene in age (10.2 Ma). They are only slightly younger than the oldest remains undoubtedly attributable to this taxon. The X-ray diffraction and Fourier Transform Infrared Spectroscopy indicate diagenetic alteration of the original bone bioapatite under dominantly marine conditions. The Late Miocene was a period of ice margin retreat and marine incursion into the Lambert embayment that followed Middle Miocene cooling of the Antarctic climate. The fossils strongly suggest that variable climatic and environmental conditions in East Antarctica may have been an important factor in the evolution of penguins there during the Neogene.

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