Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Forelimb proportions and fossorial adaptations in the scratch-digging rodent Ctenomys (Caviomorpha)

A. Elissamburu, L. De Santis and Elizabeth R. Dumont
Journal of Mammalogy
Vol. 92, No. 3 (June 2011), pp. 683-689
Stable URL: http://www.jstor.org/stable/23259829
Page Count: 7
  • Read Online (Free)
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Preview not available

Abstract

Members of the genus Ctenomys (tuco-tuco; Rodentia: Caviomorpha: Octodontidae) are considered scratch diggers. We compared the forelimbs of adult C. azarae with those of 13 species within other genera of caviomorph rodents to identify morphofunctional variation in osseous elements related to fossorial habits. Eight measurements of the humerus and ulna were used to construct five functional indices that were subjected to principal components analysis and simple comparisons among means. Ctenomys has a general morphology similar to that of terrestrial caviomorph rodents but exhibits some features that reflect its specialized fossorial condition, such as its comparatively large epicondyles. These features indicate greater muscular development and capacity for force production in the pronators and supinators of the forelimb and manus and flexors of the manus. The deltoid complex is well developed, indicating a large moment arm for the deltoid and latissimus dorsi muscles, which increases the capacity for force production on humeral flexion. Humeral indices are the best for differentiating fossorial forms from diggers, occasional diggers, generalized, and cursorial forms. Limb bone segments are used differently by highly fossorial and scratch-digging forms. Los miembros del género Ctenomys (tuco-tuco; Rodentia, Caviomorpha, Octodontidae) son considerados cavadores "scratch-digger". Comparamos la extremidad anterior de adultos de C. azarae con 13 especies de otros géneros de roedores caviomorfos para interpretar la variación morfofuncional de los elementos óseos en relación con los hábitos fosoriales. Ocho medidas del húmero y ulna se usaron para construir cinco índices funcionales, que se analizaron con análisis de componentes principales (PCA) y de diferencia de medias. Ctenomys tiene una conformación general similar a la de los roedores caviomorphos cavadores epigeos, aunque presenta caracteres particulares propios de su condición fossorial especializada, como los epicóndilos comparativamente desarrollados. Estas características indican gran desarrollo muscular y capacidad de producción de fuerzas en la pronación y supinación del zeugopodio y la mano y flexión de la mano. El complejo deltoideo está bien desarrollado, indicativo de un arma de momento grande para el complejo muscular deltoideo y el músculo latissimus dorsi, que incrementan la capacidad de producción de fuerza en la flexión del húmero. Los índices del húmero son los más indicados para diferenciar las formas fosoriales de las cavadoras, cavadoras ocasionales, generalistas y cursoriales. Se supone un uso diferente de los segmentos de la extremidad en los roedores altamente fosoriales en comparación con scratch-digger epigeos.

Page Thumbnails

  • Thumbnail: Page 
683
    683
  • Thumbnail: Page 
684
    684
  • Thumbnail: Page 
685
    685
  • Thumbnail: Page 
686
    686
  • Thumbnail: Page 
687
    687
  • Thumbnail: Page 
688
    688
  • Thumbnail: Page 
689
    689