scholarly journals The first ornithosuchid from Brazil and its macroevolutionary and phylogenetic implications for Late Triassic faunas in Gondwana

2020 ◽  
Vol 65 ◽  
Author(s):  
Rodrigo Müller ◽  
M. Belén von Baczko ◽  
Julia Desojo ◽  
Sterling Nesbitt
Keyword(s):  
Late Triassic ◽  
Phylogenetic Implications

scholarly journals Mitogenomic architecture of the multivalent endemic black clam (Villorita cyprinoides) and its phylogenetic implications

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Summaya Rahuman ◽  
N. S. Jeena ◽  
P. K. Asokan ◽  
R. Vidya ◽  
P. Vijayagopal
Keyword(s):  
Gene Order ◽  
Mitochondrial Gene ◽  
Molecular Data ◽  
Late Triassic ◽  
Protein Coding ◽  
Next Generation Sequencing Technology ◽  
Potential Marker ◽  
Phylogenetic Implications ◽  
Close Relationship ◽  
Complete Mitogenome

Abstract The Indian black clam Villorita cyprinoides (Family: Cyrenidae), an extractive commercially exploited species with aquaculture importance contributing more than 70% of clam fishery in India, is endemic to the Indian peninsula. Currently, there is very sparse information, especially on the molecular data of Villorita. The present study aims to provide a comprehensive knowledge of mitogenome architecture and assess the phylogenetic status of Cyrenidae. This has resulted in reporting the first complete mitogenome of V. cyprinoides using next-generation sequencing technology. The A+T circular mitogenome was 15,880 bp long, exhibiting 13 protein-coding genes (PCGs) including ATP8 (absent in several bivalves), 22 transfer RNA, and two ribosomal RNA genes residing in the heavy strand in a clockwise orientation and a gene order akin to Corbicula fluminea. The molecular phylogeny inferred from a concatenated multi-gene sequence [14 mitochondrial (12 PCGs, rrnS and rrnL) and two nuclear genes (Histone H3, 18S rRNA)] from 47 representative species of superorder Imparidentia, clustered V. cyprinoides and Cyrenid clams to a single clade supporting the monophyly of Cyrenidae. The subsequent mitochondrial gene order analysis substantiates the close relationship of V. cyprinoides and C. fluminea, analogous to phylogenetic output. The multilocus tree topology calibrated with verified fossil data deciphered the origin and diversification of Cyrenid clams during late Triassic-early Jurassic. The data derived from this study shall contribute remarkably for further insights on cryptic species identification, molecular characterization of bivalve mitogenomes and mitochondrial evolutionary history of genus Villorita. Moreover, complete mitogenome can aid in potential marker development for assessing the genetic health of black clam populations.

Architecture of Radiolitid Rudist (Mollusca) Shell-Wall Structures and its Phylogenetic Implications

1975 ◽  
Vol 33 ◽  
pp. 686-687
Author(s):  
David H. Sturm ◽  
Bob F. Perkins
Keyword(s):  
Phylogenetic Relationships ◽  
Outer Wall ◽  
Shell Microstructure ◽  
Shell Wall ◽  
Wall Structures ◽  
Phylogenetic Implications ◽  
Cellular Wall ◽  
Superfamily Analysis ◽  
Central Texas

Each of the seven families of rudists (Mollusca, Bivalvia, Hippuritacea) is characterized by distinctive shell-wall architectures which reflect phylogenetic relationships within the superfamily. Analysis of the complex, calcareous, cellular wall of the attached valve of the radiolite rudist Eoradiolites davidsoni (Hill) from the Comanche Cretaceous of Central Texas indicates that its wall architecture is an elaboration of the simpler monopleurid rudist wall and supports possible radiolite-monopleurid relationships.Several well-preserved specimens of E. davidsoni were sectioned, polished, etched, and carbon and gold coated for SEM examination. Maximum shell microstructure detail was displayed by etching with a 0.7% HC1 solution from 80 to 100 seconds.The shell of E. davidsoni comprises a large, thick-walled, conical, attached valve (AV) and a small, very thin, operculate, free valve (FV) (Fig. 1a). The AV shell is two-layered with a thin inner wall, in which original structures are usually obliterated by recrystallization, and a thick, cellular, outer wall.

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