HAZARD, L.C.*; SHEMANSKI, D.R.; NAGY, K.A.: Digestibility of native and exotic food plants eaten by juvenile desert tortoises Exotic plants can comprise a major component of the diet for some desert tortoises (Gopherus agassizii) in the Mojave Desert. Introduced plants may not be as nutritious as native plants. Nutrient availability in a native grass (Achnatherum […]

Stein, R.W.*; Williams, T.D.; Place, A.R.; del Rio, C.M.: Age-related differences in digestive function during migration in the Western Sandpiper (Calidris mauri) It is common practice to use species’ mean values of standardized measures, such as BMR, to evaluate changes in energy demands. However, relying upon species’ mean values becomes problematic when age-related differences are […]

GALIS, F.; VANALPHEN, J.J.M.; METZ, J.A.J.: Why five fingers? Evolutionary constraints on digit numbers Evolutionary changes in the number of digits and other limb elements appear to be severely constrained, probably as a result of a low level of modularity during limb development. Reduced limb structures typically develop through a process of construction followed by […]

DAVIS, M.C.: The evolution of paired fin development: Insights from the basal actinopterygian Polyodon The paired appendages of chondrosteans offer a good morphological and phylogenetic intermediate between derived actinopterygian (Danio) and derived sarcopterygian (Mus, Gallus) models. In particular, the paddlefish Polyodon exhibits a broad proximodistal area of overlap between the endochondral and dermal fin skeletons […]

BURIAN, R.M.: Modularity, Development, and Genotype-Phenotype Maps In this paper I examine some surprising consequences of recent results concerning the modularity of the genotype and about the importance of higher-level modules in delimiting body segments. Combining some of these findings with a characterization of genes, at the molecular level, as being nothing but sequences of […]

WOURMS, J.P.: Evolutionary trends in gut and trophotaenia-based embryonic nutrition in viviparous teleosts. Embryos of viviparous fishes acquire maternal nutrients via several routes. Enterotrophy involves the gut or gut derivatives. In the unspecialized state, nutrients imbibed from the ovarian fluid are absorbed in a simple, tubular gut. Resulting increases in embryonic weight range from slight […]

KURATANI, S.; SHIGETANI, Y.; KAWAKAMI, Y.; SUGAHARA, F.; MURAKAMI, Y.: Evolution of the vertebrate jaw through ontogenetic repatterning Evolutionary novelties can be brought about through the ontogenetic repatterning that often obliterates the structural homology. The vertebrate jaw may also be one of such novelties since oral structures of lampreys and gnathostomes cannot be homologized easily. […]

SCHLOSSER, G.*: Detection of Dissociated Coevolution of Characters using Heterochrony Plots: Mosaic Evolution of Brain Development in Direct Developing Frogs Many evolutionary modifications of development are accompanied by heterochronic shifts of character development. Frequently, only some developmental events are shifted relative to others. The detection of such mosaic alterations of character development is increasingly difficult, […]

RYBCZYNSKI, N.; Duke Univ., Durham, North Carolina: Wood-Cutting Performance in Two Castorids (Rodentia, Mammalia) Fossilized cut wood found associated with the skeletal remains of the Pliocene beaver, Dipoides, provides the first evidence of wood-cutting behavior in an extinct beaver. Unlike the modern beaver, Castor, the lower incisor tips of Dipoides are not squared-off in anterior […]

ANGIELCZYK, K.D.; University of California, Berkeley: Unexpected Homoplasy in the Anomodont (Synapsida; Therapsida) Feeding System Anomodont therapsids were the most abundant and diverse group of terrestrial vertebrate herbivores during the Late Permian and much of the Triassic. The success of anomodonts has been hypothesized to be related to their complex mastication system, which was based […]