A Novel Biting Mechanism in Damselfishes (Pomacentridae): the Pushing Up of the Lower Pharyngeal Jaw By the Pectoral Girdle

1996 ◽  
Vol 47 (4) ◽  
pp. 405-410 ◽  
Author(s):  
Frietson Galis ◽  
Peter Snelderwaard
Keyword(s):  
Pectoral Girdle ◽  
Pharyngeal Jaw

REASSESSMENT OF THE MOSASAUR PECTORAL GIRDLE AND ITS ROLE IN AQUATIC LOCOMOTION

2019 ◽  
Author(s):  
Kiersten K. Formoso ◽  
◽  
Michael B. Habib ◽  
David J. Bottjer
Keyword(s):  
Pectoral Girdle ◽  
Aquatic Locomotion

scholarly journals Gene coexpression networks reveal molecular interactions underlying cichlid jaw modularity

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Pooja Singh ◽  
Ehsan Pashay Ahi ◽  
Christian Sturmbauer
Keyword(s):  
In Silico ◽  
Regulatory Networks ◽  
Evolutionary Significance ◽  
Cichlid Species ◽  
Cichlid Fishes ◽  
Gene Coexpression ◽  
Modular Evolution ◽  
Jaw Apparatus ◽  
Coexpression Networks ◽  
Pharyngeal Jaw

Abstract Background The oral and pharyngeal jaw of cichlid fishes are a classic example of evolutionary modularity as their functional decoupling boosted trophic diversification and contributed to the success of cichlid adaptive radiations. Most studies until now have focused on the functional, morphological, or genetic aspects of cichlid jaw modularity. Here we extend this concept to include transcriptional modularity by sequencing whole transcriptomes of the two jaws and comparing their gene coexpression networks. Results We show that transcriptional decoupling of gene expression underlies the functional decoupling of cichlid oral and pharyngeal jaw apparatus and the two units are evolving independently in recently diverged cichlid species from Lake Tanganyika. Oral and pharyngeal jaw coexpression networks reflect the common origin of the jaw regulatory program as there is high preservation of gene coexpression modules between the two sets of jaws. However, there is substantial rewiring of genetic architecture within those modules. We define a global jaw coexpression network and highlight jaw-specific and species-specific modules within it. Furthermore, we annotate a comprehensive in silico gene regulatory network linking the Wnt and AHR signalling pathways to jaw morphogenesis and response to environmental cues, respectively. Components of these pathways are significantly differentially expressed between the oral and pharyngeal jaw apparatus. Conclusion This study describes the concerted expression of many genes in cichlid oral and pharyngeal jaw apparatus at the onset of the independent life of cichlid fishes. Our findings suggest that – on the basis of an ancestral gill arch network—transcriptional rewiring may have driven the modular evolution of the oral and pharyngeal jaws, highlighting the evolutionary significance of gene network reuse. The gene coexpression and in silico regulatory networks presented here are intended as resource for future studies on the genetics of vertebrate jaw morphogenesis and trophic adaptation.

scholarly journals Guianacara dacrya, a new species from the rio Branco and Essequibo River drainages of the Guiana Shield (Perciformes: Cichlidae)

2011 ◽  
Vol 9 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Jessica H Arbour ◽  
Hernán López-Fernández
Keyword(s):  
New Species ◽  
River Basins ◽  
Guiana Shield ◽  
Dorsal Fin ◽  
White Spots ◽  
Tooth Plate ◽  
Northern Brazil ◽  
Pharyngeal Jaw ◽  
River Drainages ◽  
A New Species

A new species of Guianacara is described from tributaries of the Essequibo River and the rio Branco in Guyana and northern Brazil. Guianacara dacrya, new species, can be diagnosed from all congeners by the possession of a unique infraorbital stripe and by the shape of the lateral margin of the lower pharyngeal jaw tooth plate. Guianacara dacrya can be further distinguished from G. geayi, G. owroewefi, G. sphenozona and G. stergiosi by the possession of a thin midlateral bar, from G. cuyunii by the possession of dusky branchiostegal membranes and from G. oelemariensis by the possession of two supraneurals. This species differs from most congeners by the presence of white spots on the spiny portion of the dorsal fin, the placement of the midlateral spot, the presence of filaments on the dorsal, anal and in rare cases the caudal-fin and from at least the Venezuelan species by several morphometric variables. Guianacara dacrya is known from the Essequibo, Takutu and Ireng River basins of Guyana and possibly from the rio Uraricoera in the rio Branco basin in Brazil. A key to the species is provided.

Ergonomics in the Dental Clinic

2000 ◽  
Vol 44 (26) ◽  
pp. 197-200
Author(s):  
Rose-Ange Proteau
Keyword(s):  
Return To Work ◽  
Muscular Activity ◽  
Pectoral Girdle ◽  
Dental Hygienists ◽  
Dental Clinic ◽  
Arm Support ◽  
Muscular Effort

A number of dental hygienists have developed pathologies that cause them to be absent from work for long periods of time, and making it difficult for them to return to work. Hygienists' work involves extended static muscular effort in the neck and pectoral girdle, combined with recurrent dynamic movements of the wrist and fingers, associated with efforts to remove tartar from the teeth. Over the last two years, a dozen dental hygienists have consulted us for various shoulder, elbow, wrist, hand and finger problems. Changes in methods, instruments, equipment and the environment have allowed hygienists to adopt safer working positions. Reduced muscular activity was confirmed by EMG testing. The use of telescopic pivoting armrests has facilitated the adoption of new working methods by dental hygienists, and also provided needed arm support. A new concept for a pivoting armrest has been developed with round gel elbows-rests.

Use of a caudoventral-craniodorsal oblique radiographic view made at 45° to the frontal plane to evaluate the pectoral girdle in raptors

2015 ◽  
Vol 247 (9) ◽  
pp. 1037-1041 ◽  
Author(s):  
Marike Visser ◽  
Adrien-Maxence Hespel ◽  
Marie de Swarte ◽  
Jamie R. Bellah
Keyword(s):  
Frontal Plane ◽  
Pectoral Girdle

scholarly journals The cichlid oral and pharyngeal jaws are evolutionarily and genetically coupled

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Andrew J. Conith ◽  
R. Craig Albertson
Keyword(s):  
Prey Capture ◽  
Phenotypic Change ◽  
Functional Constraints ◽  
East African ◽  
Genetic Level ◽  
Evolutionary Success ◽  
African Rift ◽  
Pharyngeal Jaws ◽  
African Cichlids ◽  
Pharyngeal Jaw

AbstractEvolutionary constraints may significantly bias phenotypic change, while “breaking” from such constraints can lead to expanded ecological opportunity. Ray-finned fishes have broken functional constraints by developing two jaws (oral-pharyngeal), decoupling prey capture (oral jaw) from processing (pharyngeal jaw). It is hypothesized that the oral and pharyngeal jaws represent independent evolutionary modules and this facilitated diversification in feeding architectures. Here we test this hypothesis in African cichlids. Contrary to our expectation, we find integration between jaws at multiple evolutionary levels. Next, we document integration at the genetic level, and identify a candidate gene, smad7, within a pleiotropic locus for oral and pharyngeal jaw shape that exhibits correlated expression between the two tissues. Collectively, our data show that African cichlid evolutionary success has occurred within the context of a coupled jaw system, an attribute that may be driving adaptive evolution in this iconic group by facilitating rapid shifts between foraging habitats, providing an advantage in a stochastic environment such as the East African Rift-Valley.

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