Literaturdatenbank
Literaturdatenbank |
|
 |
|
Dalrymple, G. H. (1977). Intraspecific variation in the cranial feeding mechanism of turtles of the genus trionyx (reptilia, testudines, trionychidae. Journal of Herpetology, 11(3), 255–285.
Added by: Admin (21 Nov 2009 11:53:09 UTC) |
| Resource type: Journal Article BibTeX citation key: Dalyrymple1977 View all bibliographic details  |
Categories: General Keywords: Apalone, Apalone ferox, Morphologie = morphology, Schildkröten = turtles + tortoises, Systematik = taxonomy, Trionychidae Creators: Dalrymple Collection: Journal of Herpetology |
Views: 5/696
Views index: 13% Popularity index: 3.25% |
| Abstract |
|
Extreme variation in the form of the jaws occurs within at least five species of soft-shelled turtles (genus Apalone). A sample of 91 whole Apalone ferox, collected in southern Florida, was studied to determine the relationship of variation in the jaws to cranial anatomy, gut contents, size and sex. Observations were made on the feeding methods of specimens kept in the laboratory. Variation in the form of the jaws is explained as part of the physiological adaptation of the cranial feeding mechanism to changing diet with growth in size and time. Variation in the jaws of T. ferox is shown to be co-existent with variation in 1) other skull features which are presumed to be part of the cranial feeding mechanism, 2) the rhamphotheca or beak, 3) jaw musculature, and 4) feeding habits. In T. ferox, females attain larger size and show more extreme variation in cranial form and diet than males; however the allometric trends are common to both sexes. The relative development of the different features of the cranial feeding mechanism does not reflect a highly integrated structural system. There is no evidence of sexual dimorphism (sensu stricto) nor is there a high correlation between individual skull form and specific fooditems. Such a loosely correlated system indicates low selection pressures regarding trophic specialization; individual homeostasis would appear to be a sufficient adaptive strategy.
Added by: Admin |