Dental Ontogeny in Lacerta lepida (Sauria, Lacertidae) and Its Relationship to Diet

Copeia ◽  
1997 ◽  
Vol 1997 (2) ◽  
pp. 461 ◽  
Author(s):  
José A. Mateo ◽  
Luis F. López-Jurado ◽  
Jose A. Mateo ◽  
Luis F. Lopez-Jurado
Keyword(s):  
2010 ◽  
Vol 84 (6) ◽  
pp. 1152-1176 ◽  
Author(s):  
Ilya Tëmkin ◽  
John Pojeta

An exceptionally well-preserved silicified bivalve from the Upper Permian of Texas is described and assigned to a new genus and species,Cassiavellia galtarae, placed in the family Bakevelliidae. The species represents one of the earliest and best characterized unequivocal occurrences of the multivincular ligament in the superfamily Pterioidea. The silicified material provides a wealth of information on the morphology of inadequately known Paleozoic pterioideans, including hitherto undescribed aspects of the larval shell, auricular sulcus, muscle scars, and dental ontogeny. The discovery of the condyle-fossa complex on the anteroventral shell margin, a feature previously undescibed in Bivalvia, raises the question of the homology and taxonomic significance of the problematic subumbonal ridge-like structures in Pterioidea. In life,C. galtaraewas probably an epifaunal right-pleurothetic bivalve, byssally attached to hard or raised flexible substrata. In addition toC. galtarae, another new species,C. nadkevnae, is placed inCassiavellia.


1982 ◽  
Vol 63 (3) ◽  
pp. 527-529
Author(s):  
J. W. Hermanson ◽  
C. A. Woods ◽  
K. M. Howell
Keyword(s):  

2017 ◽  
Vol 4 (7) ◽  
pp. 170494 ◽  
Author(s):  
Helder Gomes Rodrigues ◽  
Rémi Lefebvre ◽  
Marcos Fernández-Monescillo ◽  
Bernardino Mamani Quispe ◽  
Guillaume Billet

Studying dental ontogeny in mammals can provide valuable insight on the evolution of their masticatory apparatus and their related adaptations. The multiple acquisitions of a prolonged to continuous growth of teeth in herbivorous mammals in response to high abrasion represent an intensively investigated issue. However, the ontogenetic and architectural patterns associated with these repeated dental innovations remain poorly known. Here, we focused on two case studies corresponding to distant mammalian clades, the extinct Mesotheriidae (Notoungulata), which shared some striking dental features with the extant Ctenodactylidae (Rodentia). We studied the impact of prolonged to continuous growth of molars on their occlusal complexity, their relative size and their dynamics in the jaw. We found that variations of occlusal complexity patterns are the result of paedomorphic or peramorphic heterochronic processes impacting dental crown. We showed that variations in both upper and lower molar proportions generally follow the inhibitory developmental cascade model. In that context, prolonged dental growth implies transitory adjustments due to wear, and also involves dental migration and loss when combined with molar lengthening. Interestingly, these features may be present in many mammals having prolonged dental growth, and emphasize the crucial need of considering these aspects in future evolutionary and developmental studies.


Primates ◽  
1981 ◽  
Vol 22 (1) ◽  
pp. 103-118 ◽  
Author(s):  
Kenneth E. Byrd
Keyword(s):  

2017 ◽  
Vol 232 (3) ◽  
pp. 371-382 ◽  
Author(s):  
Yara Haridy ◽  
Aaron R. H. LeBlanc ◽  
Robert R. Reisz

Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  

AbstractOntogenetic data obtained by synchrotron microtomography of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically basalmost stem osteichthyan, reveal developmental relationships between teeth and ornament that are not obvious from the adult morphology. The earliest odontodes are two longitudinal founder ridges formed at the ossification center. Subsequent odontodes that are added lingually to the ridges turn into conical teeth and undergo cyclic replacement, while those added labially achieve a stellate appearance. The stellate odontodes deposited directly on the bony plate are aligned with the alternate files of the teeth. Successive odontodes overgrowing the labial tooth rows become tooth-like and the replacement teeth near to them are ornament-like. We propose that teeth and ornament are modifications of a single odontode system regulated and differentiated by the oral and dermal signals; signal cross-communication between the two domains can occur around the oral-dermal boundary.


Paleobiology ◽  
1989 ◽  
Vol 15 (2) ◽  
pp. 165-179 ◽  
Author(s):  
V. Louise Roth

A marked retardation of dental ontogeny characterizes the family Elephantidae. As a consequence of this retardation, elephant teeth are subject to the forces of mastication, eruption, and progression while still in a developing and pliant stage. As specimens described here illustrate, the mechanical forces are often sufficient to deform the gross morphology of dentitions. Morphological variation in elephant teeth can be regarded as “fabricational noise”—revealing information about the dynamic context in which the teeth develop. Accordingly, dental variation is less species-specific in elephants than in other mammals. The fossil record may comprise fewer species of elephants than is generally believed, and trends inferred to reflect rapid evolution within this family may in fact reflect phenotypic plasticity.


1987 ◽  
Vol 65 (6) ◽  
pp. 1425-1434 ◽  
Author(s):  
R. E. A. Stewart ◽  
B. E. Stewart

Harp seal fetuses and neonates were examined to determine the development, resorption, and eruption characteristics of deciduous and permanent dentition. Early September fetuses had recently formed, deciduous teeth only. By early December the deciduous dentition was robust and enameled. Permanent teeth were also present. In late December the roots of the deciduous teeth were being resorbed and the permanent dentition was larger and better developed. About 80% of the deciduous teeth were resorbed by birth in March. The rest were resorbed or shed after birth. The pattern of permanent tooth eruption was not correlated with pup age but the total number of teeth erupted increased significantly with increasing pup age, from 38% in newborns to 100% in weaned pups about 3 weeks old. The neonatal line formed at birth rather than at weaning or the onset of moult.


PLoS ONE ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. e0175460 ◽  
Author(s):  
Yangfan Li ◽  
Tao Deng ◽  
Hong Hua ◽  
Yongxiang Li ◽  
Yunxiang Zhang

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