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Mandible Length (mandible + length)
Selected AbstractsInterpopulation differences in the mandible size of the coastal tiger beetle Lophyridia angulata associated with different sympatric speciesENTOMOLOGICAL SCIENCE, Issue 3 2004Aya SATOH Abstract The coastal tiger beetle Lophyridia angulata (Fabricius) co-occurs with one or two tiger beetle species at any one locality (in a sandy beach habitat) along the Japan Sea coast of Honshu, from eastern to southern Kyushu, and on Tanega-shima, an island south of Kyushu, in Japan. Lophyridia angulata displays sexual dimorphism in mandible length (the mandible is longer in females), and shows large interpopulation differences in mandible size. We analyzed variation in mandible length between L. angulata populations associated with three different sympatric species, and examined morphological differences that may have resulted from interaction with these other species. Lophyridia angulata showed a significant size shift towards larger mandibles in a population that co-occurred with Cicindela lewisii, which has a similar mandible length to that of L. angulata, as compared to a neighboring population of L. angulata that co-occurred with another species. This pattern may be interpreted as a type of character displacement associated with food resource competition. Males in L. angulata populations co-occurring with Chaetodera laetescripta showed little variation in mandible length, as compared to other populations. These males may experience some pressure from C. laetescripta and from conspecific females. We found no significant changes in mandible length or in size variation of L. angulata before and 20 years after the extinction of Abroscelis anchoralis at one site historically co-inhabited by both species; that is, we did not detect a character release over the 20 years. [source] Maximum ingested food size in captive strepsirrhine primates: Scaling and the effects of dietAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010Jonathan M.G. Perry Abstract Little is known about ingested food size (Vb) in primates, even though this variable has potentially important effects on food intake and processing. This study provides the first data on Vb in strepsirrhine primates using a captive sample of 17 species. These data can be used for generating and testing models of feeding energetics. Strepsirrhines are of interest because they are hypometabolic and chewing rate and daily feeding time do not show a significant scaling relationship with body size. Using melon, carrot, and sweet potato we found that maximum Vb scales isometrically with body mass and mandible length. Low dietary quality in larger strepsirrhines might explain why Vb increases with body size at a greater rate than does resting metabolic rate. Relative to body size, Vb is large in frugivores but small in folivores; furthermore scaling slopes are higher in frugivores than in folivores. A gross estimate of dietary quality explains much of the variation in Vb that is not explained by body size. Gape adaptations might favor habitually large bites for frugivores and small ones for folivores. More data are required for several feeding variables and for wild populations. Am J Phys Anthropol 142:625,635, 2010. © 2010 Wiley-Liss, Inc. [source] Brief communication: Noninvasive measuring of operational tongue length in callitrichidsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Eckhard W. Heymann Abstract Callitrichids use their tongue in various social, ecological, and hygienic contexts. Using a noninvasive measuring device, we obtained data on the operational tongue length (OTL) in seven species from the family Callitrichidae. OTL (defined as the maximum tongue extension into the device) varied significantly between species and the width of the device, but did not correlate with mandible length; it is smaller in relation to mandible length in Leontopithecus chrysomelas compared to species from the genera Saguinus and Callithrix. Current information does not allow concluding which of the various functions of the tongue is selecting for tongue length. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source] Scaling of chew cycle duration in primatesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Callum F. Ross Abstract The biomechanical determinants of the scaling of chew cycle duration are important components of models of primate feeding systems at all levels, from the neuromechanical to the ecological. Chew cycle durations were estimated in 35 species of primates and analyzed in conjunction with data on morphological variables of the feeding system estimating moment of inertia of the mandible and force production capacity of the chewing muscles. Data on scaling of primate chew cycle duration were compared with the predictions of simple pendulum and forced mass,spring system models of the feeding system. The gravity-driven pendulum model best predicts the observed cycle duration scaling but isrejected as biomechanically unrealistic. The forced mass,spring model predicts larger increases in chew cycle duration with size than observed, but provides reasonable predictions of cycle duration scaling. We hypothesize that intrinsic properties of the muscles predict spring-like behavior of the jaw elevator muscles during opening and fast close phases of the jaw cycle and that modulation of stiffness by the central nervous system leads to spring-like properties during the slow close/power stroke phase. Strepsirrhines show no predictable relationship between chew cycle duration and jaw length. Anthropoids have longer chew cycle durations than nonprimate mammals with similar mandible lengths, possibly due to their enlarged symphyses, which increase the moment of inertia of the mandible. Deviations from general scaling trends suggest that both scaling of the jaw muscles and the inertial properties of the mandible are important in determining the scaling of chew cycle duration in primates. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] | ||||||||||