Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order
The defining characteristic of the mammalian order Rodentia is a pair of continually growing incisors (Figure 1). There are rodents that scamper, hop, burrow, swim, and glide; that eat seeds, grass, nuts, insects, and worms; that live in the tropics, arctic, and temperate regions, in, on, or above t...
Published in: | Notes for a Short Course: Studies in Geology |
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Cambridge University Press (CUP)
1984
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crcambridgeupr:10.1017/s0271164800000944 2024-03-03T08:42:02+00:00 Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order Jacobs, Louis L. 1984 http://dx.doi.org/10.1017/s0271164800000944 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0271164800000944 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Notes for a Short Course: Studies in Geology volume 8, page 155-166 ISSN 0271-1648 2475-9201 journal-article 1984 crcambridgeupr https://doi.org/10.1017/s0271164800000944 2024-02-08T08:28:34Z The defining characteristic of the mammalian order Rodentia is a pair of continually growing incisors (Figure 1). There are rodents that scamper, hop, burrow, swim, and glide; that eat seeds, grass, nuts, insects, and worms; that live in the tropics, arctic, and temperate regions, in, on, or above the surface of the earth; in desert, grassland, savannah, and forest, but all are easily recognized by the incisors and correlated features. The lower incisors grow as helices approximating arcs. The upper incisor represents a relatively larger arc of a smaller circle than the lower incisor, which is a smaller arc of a larger circle. The root of each incisor is far back in the jaw. Enamel is essentially restricted to the labial surface of the incisors and comprises two layers. The wear of lower incisors against uppers, the distribution of enamel, the relative hardness of enamel versus dentine, and continual growth results in the maintenance of a sharp chisel edge. Thus, the gnawing incisors are primary food-gathering organs for rodents, but can also function in a number of other ways, such as in digging or as forceps. Article in Journal/Newspaper Arctic Cambridge University Press Arctic Notes for a Short Course: Studies in Geology 8 155 166 |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
The defining characteristic of the mammalian order Rodentia is a pair of continually growing incisors (Figure 1). There are rodents that scamper, hop, burrow, swim, and glide; that eat seeds, grass, nuts, insects, and worms; that live in the tropics, arctic, and temperate regions, in, on, or above the surface of the earth; in desert, grassland, savannah, and forest, but all are easily recognized by the incisors and correlated features. The lower incisors grow as helices approximating arcs. The upper incisor represents a relatively larger arc of a smaller circle than the lower incisor, which is a smaller arc of a larger circle. The root of each incisor is far back in the jaw. Enamel is essentially restricted to the labial surface of the incisors and comprises two layers. The wear of lower incisors against uppers, the distribution of enamel, the relative hardness of enamel versus dentine, and continual growth results in the maintenance of a sharp chisel edge. Thus, the gnawing incisors are primary food-gathering organs for rodents, but can also function in a number of other ways, such as in digging or as forceps. |
format |
Article in Journal/Newspaper |
author |
Jacobs, Louis L. |
spellingShingle |
Jacobs, Louis L. Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order |
author_facet |
Jacobs, Louis L. |
author_sort |
Jacobs, Louis L. |
title |
Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order |
title_short |
Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order |
title_full |
Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order |
title_fullStr |
Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order |
title_full_unstemmed |
Rodentia: Extraordinary Diversification of a Morphologically Distinctive and Stereotyped Order |
title_sort |
rodentia: extraordinary diversification of a morphologically distinctive and stereotyped order |
publisher |
Cambridge University Press (CUP) |
publishDate |
1984 |
url |
http://dx.doi.org/10.1017/s0271164800000944 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0271164800000944 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Notes for a Short Course: Studies in Geology volume 8, page 155-166 ISSN 0271-1648 2475-9201 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0271164800000944 |
container_title |
Notes for a Short Course: Studies in Geology |
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8 |
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155 |
op_container_end_page |
166 |
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