scholarly journals A histological investigation of dental crown characters used in mosasaur phylogenetic analyses

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hallie Street ◽  
Aaron LeBlanc ◽  
Michael Caldwell
Keyword(s):  
Histological Analysis ◽  
Phylogenetic Analyses ◽  
Histological Investigation ◽  
Developmental Origins ◽  
Common Ancestry ◽  
Tooth Crown ◽  
Tooth Morphology ◽  
Relative Contribution ◽  
Distinct Character ◽  
Dental Crown

Mosasaur researchers have used varieties of tooth crown ornamentation as diagnostic and phylogenetic characters for decades. Such tooth crown features include facets, flutes, striations, serrated carinae, and coarse anastomosing texture. This study investigates the relative contribution of dentine and enamel to the development of these dental characters and assesses possible homologies between these structures. Histological analysis of isolated mosasaur teeth revealed that flutes and facets develop initially from the dentine, and the external enamel morphology we observe macroscopically mirrors the shape the underlying dentine. Striations combine underlying contributions from the dentine with additional and irregular enamel deposition that results strictly from amelogenesis. In both serrated carinae and anastomosing texture the border between the dentine and the enamel is smooth, and these external ornamentations form through variations in enamel development. Based on these observations, we infer that flutes and facets are part of a morphological spectrum and should not be treated as separate phylogenetic characters. Conversely, striations develop differently than flutes and facets, and should therefore be treated as a distinct character. We recommend referring to the “serrations” on mosasaur carinae as crenulations to differentiate these enamel-only structures from true denticles possessing a dentine core. Anastomosing texture can also coincide with significant apical thickening, both of which could be adaptations for processing hard-shelled prey. Care must be taken when using tooth crown features as diagnostic or phylogenetic characters because seemingly different morphologies can have similar developmental origins, and tooth morphology can be more closely tied to diet than to common ancestry.

An Ancient Retrovirus-like Element Contains Hot Spots for SINE Insertion

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 769-777
Author(s):  
Michael A Cantrell ◽  
Brian J Filanoski ◽  
Angela R Ingermann ◽  
Katherine Olsson ◽  
Nicole DiLuglio ◽  
...  
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Phylogenetic Analyses ◽  
Common Ancestry ◽  
Specific Element ◽  
Sine Insertion ◽  
Specific Locus ◽  
Multiple Species ◽  
Phylogenetic Character ◽  
Over Time

Abstract Vertebrate retrotransposons have been used extensively for phylogenetic analyses and studies of molecular evolution. Information can be obtained from specific inserts either by comparing sequence differences that have accumulated over time in orthologous copies of that insert or by determining the presence or absence of that specific element at a particular site. The presence of specific copies has been deemed to be an essentially homoplasy-free phylogenetic character because the probability of multiple independent insertions into any one site has been believed to be nil. Mys elements are a type of LTR-containing retrotransposon present in Sigmodontine rodents. In this study we have shown that one particular insert, mys-9, is an extremely old insert present in multiple species of the genus Peromyscus. We have found that different copies of this insert show a surprising range of sizes, due primarily to a continuing series of SINE (short interspersed element) insertions into this locus. We have identified two hot spots for SINE insertion within mys-9 and at each hot spot have found that two independent SINE insertions have occurred at identical sites. These results have major repercussions for phylogenetic analyses based on SINE insertions, indicating the need for caution when one concludes that the existence of a SINE at a specific locus in multiple individuals is indicative of common ancestry. Although independent insertions at the same locus may be rare, SINE insertions are not homoplasy-free phylogenetic markers.

scholarly journals The phylogeny of desmostylians revisited: proposal of new clades based on robust phylogenetic hypotheses

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7430
Author(s):  
Kumiko Matsui ◽  
Takanobu Tsuihiji
Keyword(s):  
Phylogenetic Analyses ◽  
Data Matrix ◽  
Common Ancestry ◽  
Consensus Trees ◽  
Phylogenetic Hypotheses ◽  
Aquatic Mammals ◽  
Data Matrices

Background Desmostylia is a clade of extinct aquatic mammals with no living members. Today, this clade is considered belonging to either Afrotheria or Perissodactyla. In the currently-accepted taxonomic scheme, Desmostylia includes two families, 10 to 12 genera, and 13–14 species. There have been relatively few phylogenetic analyses published on desmostylian interrelationship compared to other vertebrate taxa, and two main, alternative phylogenetic hypotheses have been proposed in previous studies. One major problem with those previous studies is that the numbers of characters and OTUs were small. Methods In this study, we analyzed the phylogenetic interrelationship of Desmostylia based on a new data matrix that includes larger numbers of characters and taxa than in any previous studies. The new data matrix was compiled mainly based on data matrices of previous studies and included three outgroups and 13 desmostylian ingroup taxa. Analyses were carried out using five kinds of parsimonious methods. Results Strict consensus trees of the most parsimonious topologies obtained in all analyses supported the monophyly of Desmostylidae and paraphyly of traditional Paleoparadoxiidae. Based on these results, we propose phylogenetic definitions of the clades Desmostylidae and Paleoparadoxiidae based on common ancestry.

scholarly journals A new eusuchian (Crocodylia) tooth from the Early or Middle Paleocene, with a description of the Early–Middle Paleocene boundary succession at Gemmas Allé, Copenhagen, Denmark

2014 ◽  
Vol 62 ◽  
pp. 17-26
Author(s):  
Daniela Schwarz Wings ◽  
Jesper Milàn ◽  
Palle Gravesen
Keyword(s):  
Late Cretaceous ◽  
Northern Europe ◽  
Tooth Crown ◽  
Southern Sweden ◽  
Tooth Morphology ◽  
Rounded Apex ◽  
Southern Scandinavia ◽  
Basal Conglomerate

A recently found crocodylian tooth crown from the basal conglomerate of the Middle Paleocene (Selandian) Lellinge Greensand Formation, differs morphologically from other finds of crocodylian teeth from the Paleocene of southern Scandinavia. The tooth is conical and blunt with a narrow rounded apex, and slightly curved along the axis of its length. The morphology of the tooth suggests it belongs to either the longirostrine eusuchian Aigialosuchus, which is known from the Campanian of southern Sweden, or to a member of the Alligatoridae which are the most common crocodylians in northern Europe in the Late Cretaceous. Gavialoid crocodylians, in particular Thoracosaurus which is known from the Danian limestome of the Limhamn quarry in southern Sweden and from the Faxe quarry in eastern Denmark, can be excluded because of their deviating tooth morphology. Regardless of its assignment, the tooth is interesting in a stratigraphic context as it demonstrates the existence of at least two crocodylian taxa in Scandinavia during the Early and Middle Paleocene.

New aristonectine elasmosaurid plesiosaur specimens from the Early Maastrichtian of Angola and comments on paedomorphism in plesiosaurs

2015 ◽  
Vol 94 (1) ◽  
pp. 93-108 ◽  
Author(s):  
R. Araújo ◽  
M.J. Polcyn ◽  
J. Lindgren ◽  
L.L. Jacobs ◽  
A.S. Schulp ◽  
...  
Keyword(s):  
New Zealand ◽  
Histological Analysis ◽  
Phylogenetic Analyses ◽  
External Morphology ◽  
Sister Taxon ◽  
Close Relationship

AbstractNew elasmosaurid plesiosaur specimens are described from the Early Maastrichtian of Angola. Phylogenetic analyses reconstruct the Angolan taxon as an aristonectine elasmosaurid and the sister taxon of an unnamed form of similar age from New Zealand. Comparisons also indicate a close relationship with an unnamed form previously described from Patagonia. All of these specimens exhibit an ostensibly osteologically immature external morphology, but histological analysis of the Angolan material suggests an adult with paedomorphic traits. By extension, the similarity of the Angolan, New Zealand and Patagonian material indicates that these specimens represent a widespread paedomorphic yet unnamed taxon.

Muscles versus bones: catfishes as a case study for a discussion on the relative contribution of myological and osteological features in phylogenetic reconstructions

2004 ◽  
Vol 54 (4) ◽  
pp. 373-391 ◽  
Author(s):  
Rui Diogo
Keyword(s):  
Morphological Variation ◽  
Phylogenetic Trees ◽  
High Reliability ◽  
Phylogenetic Analyses ◽  
Data Sets ◽  
Large Set ◽  
Relative Contribution ◽  
Phylogenetic Reconstructions ◽  
The Subject

AbstractThe levels of homoplasy and phylogenetic reliability of different types of data sets have since long intrigued evolutionary scientists. This paper provides, to the author's knowledge, the first assessment of the relative contribution of a large set of myological and osteological characters in simultaneous phylogenetic analyses. The biological taxon used as a case study for this comparison was the highly diverse and cosmopolitan teleost Siluriformes (catfishes) which, with 34 families, about 437 genera and more than 2700 species, represents about one third of all freshwater fishes and one of the most diverse vertebrate groups. Such a direct comparison of the relative contribution of these two types of data sets has the advantage that the homoplasy levels and the phylogenetic trees being compared refer to the same group and, more importantly, to the very same terminal taxa. The overall analysis of the results presented in this work seems to indicate that: (1) osteological structures display a greater morphological variation than myological ones; (2) this difference (which is very likely overenhanced by the fact that the phylogenetic variation of osteological structures has historically been the subject of many more studies and descriptions than myological ones) is particularly notable in small taxa, such as genera or species; (3) myological characters provide, however, a high proportion of informative characters for disclosing the relationships between larger taxa, and, thus, for disclosing the phylogeny of the higher clades in which these taxa are included. These results raise some puzzling, general questions. For instance, what are the reasons for the seemingly greater morphological variation of osteological structures? And why is this greater morphological variation of osteological structures in relation to myological structures particularly pronounced in low ranking taxa? Does natural selection eventually act, in certain cases, more on bones than on muscles? Is the development of myological structures eventually more constrained than that of osteological features? What explains the apparently high reliability of muscular characters to disclose the higher-level phylogeny of higher taxa? More direct comparisons, either of other major groups of teleosts or of vertebrates in general, are clearly needed to infer if the patterns found in the direct comparison of this work correspond to a more general phylogenetic pattern, or instead refer to a particular situation found in the order Siluriformes.

scholarly journals Common Ancestry of Borrelia burgdorferiSensu Lato Strains from North America and Europe

1999 ◽  
Vol 37 (9) ◽  
pp. 3010-3012 ◽  
Author(s):  
D. Postic ◽  
N. Marti Ras ◽  
R. S. Lane ◽  
P.-F. Humair ◽  
M. M. Wittenbrink ◽  
...  
Keyword(s):  
United States ◽  
North America ◽  
Borrelia Burgdorferi ◽  
North American ◽  
Phylogenetic Analyses ◽  
The United States ◽  
Whole Genome ◽  
Common Ancestry ◽  
Limited Region

Ten atypical European Borrelia burgdorferi sensu lato (Borrelia spp.) strains were genetically characterized, and the diversity was compared to that encountered among relatedBorrelia spp. from North America. Phylogenetic analyses of a limited region of the genome and of the whole genome extend existing knowledge about borrelial diversity reported earlier in Europe and the United States. Our results accord with the evidence that North American and European strains may have a common ancestry.

scholarly journals Expanded Genomic Sampling of the Desulfobulbales Reveals Distribution and Evolution of Sulfur Metabolisms

2021 ◽  
Author(s):  
Lewis M. Ward ◽  
Emma Bertran ◽  
David T. Johnston
Keyword(s):  
Sulfate Reduction ◽  
Sulfur Metabolism ◽  
Phylogenetic Analyses ◽  
Genomic Diversity ◽  
Test Case ◽  
Sulfur Disproportionation ◽  
Sulfate Reducing ◽  
Relative Contribution ◽  
Microbial Sulfate Reduction ◽  
Reducing Bacteria

AbstractThe reconstruction of modern and paleo-sulfur cycling relies on understanding the long-term relative contribution of its main actors; these include microbial sulfate reduction (MSR) and microbial sulfur disproportionation (MSD). However, a unifying theory is lacking for how MSR and MSD, with the same enzyme machinery and intimately linked evolutionary histories, perform two drastically different metabolisms. Here, we aim at shedding some light on the distribution, diversity, and evolutionary histories of MSR and MSD, with a focus on the Desulfobulbales as a test case. The Desulfobulbales is a diverse and widespread order of bacteria in the Desulfobacterota (formerly Deltaproteobacteria) phylum primarily composed of sulfate reducing bacteria. Recent culture- and sequence-based approaches have revealed an expanded diversity of organisms and metabolisms within this clade, including the presence of obligate and facultative sulfur disproportionators. Here, we present draft genomes of previously unsequenced species of Desulfobulbales, substantially expanding the available genomic diversity of this clade. We leverage this expanded genomic sampling to perform phylogenetic analyses, revealing an evolutionary history defined by vertical inheritance of sulfur metabolism genes with numerous convergent instances of transition from sulfate reduction to sulfur disproportionation.

The Late Cretaceous shark Ptychodus marginalis in the Western Interior Seaway, USA

2010 ◽  
Vol 84 (3) ◽  
pp. 538-548 ◽  
Author(s):  
Shawn A. Hamm
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Type Specimen ◽  
Tooth Crown ◽  
Western Interior Seaway ◽  
Tooth Morphology

Re-evaluation of teeth referred to the Late Cretaceous shark Ptychodus polygyrus from North America are hereby determined to be synonymous with another species having similar tooth morphology, Ptychodus marginalis Agassiz. Ptychodus marginalis differs from P. polygyrus by having an elevated and rounded tooth crown with transverse ridges restricted centrally on the apex of the crown with a clearly defined marginal area. The type specimen of P. marginalis was described from Middle Cenomanian to Middle Turonian deposits in the English Chalk, and teeth possessing identical tooth morphologies are found within contemporary units in North America, whereas teeth having the typical P. polygyrus morphology are restricted to Late Santonian-Early Campanian deposits.

scholarly journals Expanded Genomic Sampling Refines Current Understanding of the Distribution and Evolution of Sulfur Metabolisms in the Desulfobulbales

2021 ◽  
Vol 12 ◽  
Author(s):  
Lewis M. Ward ◽  
Emma Bertran ◽  
David T. Johnston
Keyword(s):  
Sulfate Reduction ◽  
Sulfur Metabolism ◽  
Phylogenetic Analyses ◽  
Genomic Diversity ◽  
Test Case ◽  
Sulfur Disproportionation ◽  
Sulfate Reducing ◽  
Relative Contribution ◽  
Microbial Sulfate Reduction ◽  
Reducing Bacteria

The reconstruction of modern and paleo-sulfur cycling relies on understanding the long-term relative contribution of its main actors; these include microbial sulfate reduction (MSR) and microbial sulfur disproportionation (MSD). However, a unifying theory is lacking for how MSR and MSD, with the same enzyme machinery and intimately linked evolutionary histories, perform two drastically different metabolisms. Here, we aim at shedding some light on the distribution, diversity, and evolutionary histories of MSR and MSD, with a focus on the Desulfobulbales as a test case. The Desulfobulbales is a diverse and widespread order of bacteria in the Desulfobacterota (formerly Deltaproteobacteria) phylum primarily composed of sulfate reducing bacteria. Recent culture- and sequence-based approaches have revealed an expanded diversity of organisms and metabolisms within this clade, including the presence of obligate and facultative sulfur disproportionators. Here, we present draft genomes of previously unsequenced species of Desulfobulbales, substantially expanding the available genomic diversity of this clade. We leverage this expanded genomic sampling to perform phylogenetic analyses, revealing an evolutionary history defined by vertical inheritance of sulfur metabolism genes with numerous convergent instances of transition from sulfate reduction to sulfur disproportionation.

scholarly journals Phylogeny and evolution of Lasiopodomys in subfamily Arvivolinae based on mitochondrial genomics

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10850
Author(s):  
Luye Shi ◽  
Likuan Liu ◽  
Xiujuan Li ◽  
Yue Wu ◽  
Xiangyu Tian ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Early Pleistocene ◽  
Individual Species ◽  
Protein Coding ◽  
Climatic Fluctuations ◽  
Transfer Rnas ◽  
Relative Contribution ◽  
Gc Skew ◽  
Phylogeny And Evolution

The species of Lasiopodomys Lataste 1887 with their related genera remains undetermined owing to inconsistent morphological characteristics and molecular phylogeny. To investigate the phylogenetic relationship and speciation among species of the genus Lasiopodomys, we sequenced and annotated the whole mitochondrial genomes of three individual species, namely Lasiopodomys brandtii Radde 1861, L. mandarinus Milne-Edwards 1871, and Neodon (Lasiopodomys) fuscus Büchner 1889. The nucleotide sequences of the circular mitogenomes were identical for each individual species of L. brandtii, L. mandarinus, and N. fuscus. Each species contained 13 protein-coding genes (PCGs), 22 transfer RNAs, and 2 ribosomal RNAs, with mitochondrial genome lengths of 16,557 bp, 16,562 bp, and 16,324 bp, respectively. The mitogenomes and PCGs showed positive AT skew and negative GC skew. Mitogenomic phylogenetic analyses suggested that L. brandtii, L. mandarinus, and L. gregalis Pallas 1779 belong to the genus Lasiopodomys, whereas N. fuscus belongs to the genus Neodon grouped with N. irene. Lasiopodomys showed the closest relationship with Microtus fortis Büchner 1889 and M. kikuchii Kuroda 1920, which are considered as the paraphyletic species of genera Microtus. TMRCA and niche model analysis revealed that Lasiopodomys may have first appeared during the early Pleistocene epoch. Further, L. gregalis separated from others over 1.53 million years ago (Ma) and then diverged into L. brandtii and L. mandarinus 0.76 Ma. The relative contribution of climatic fluctuations to speciation and selection in this group requires further research.

Sign in / Sign up

Export Citation Format

Share Document