TRACY, C.R.: Geographic variation in sexual dimorphism of chuckwallas (Sauromalus obesus: Iguanidae): natural selection vs. sexual selection? Chuckwallas (Sauromalus obesus: Iguanidae) show a considerable geographic variation in adult body size and dimensions, with adults of some populations nearly twice the mass and 130% the snout-vent length of other populations. Additionally, chuckwallas show sexual dimorphism in […]

PFENNIG, K.S.: Differential Selection to Avoid Hybridization and its Role in Speciation by Reinforcement The fitness effects of hybridization critically affect the outcome of speciation. When hybridization is costly, selection favors the evolution of female preferences that reduce heterospecific matings, and, consequently, enhances reproductive isolation between species (i.e., reinforcement). When the costs of heterospecific matings […]

KUCHTA, S R: Color pattern evolution in a ring species: Does Ensatina eschscholtzii xanthoptica mimic newts (genus Taricha)? The salamander Ensatina eschscholtzii in California consists of seven subspecies distributed in a ring around the Central Valley. Transitions among adjacent subspecies are generally gradual, with the exception of two sympatric, reproductively isolated subspecies in southern California. […]

DALY, M: What’s in a name? Taxonomy, usage and circumscription in the genus Anthopleura (Cnidaria: Anthozoa: Actiniaria) Nomenclature evolves, as the circumscription, composition, and application of names adapt to the knowledge and needs of scientists. Taxonomic boundaries also evolve, as additional information about anatomy, life history and biology are incorporated into taxonomic circumscriptions. Discrepancies between […]

JEFFERY, J.E.*; BININDA-EMONDS, O.R.P.; COATES, M.I.; RICHARDSON, M.K.: Using Heterochrony to Reconstruct Phylogeny Numerous studies have shown that change in the sequence of development is a widespread phenomenon in vertebrate evolution. However, these heterochronies are usually examined on pre-existing phylogenies, rather than used as data for phylogenetic reconstruction. Before such data can be used in […]

COLE, A.G.; HALL, B.K.: Non-vertebrate cartilage: A phylogenetic analysis Cartilage is often thought of as solely a vertebrate tissue, although cartilage-like tissue is found in a number of species, from a diversity of groups [eg. molluscs, sabellid polychaetes, and arthropods]. The relationship between these tissues and vertebrate cartilage is not clear, although I will discuss […]

THACKER, R.W.*; STARNES, S.: Host Specificity of Symbiotic Cyanobacteria in Marine Sponges Although marine sponges can host a variety of cyanobacterial and bacterial symbionts, it is often not known whether these symbionts are generalists that occur in a variety of host species or specialists that occur only in certain species or populations of sponges. We […]

BLOMBERG, S.P.; IVES, A.R.; GARLAND, T.: Detecting Phylogenetic Signal in Comparative Data Most species resemble their nearest relatives, yet a general comparative method that measures such phylogenetic “signal” is not yet available. We present new procedures for measuring phylogenetic signal in continuous-valued characters, which use information on both topology and branch lengths. The procedures can […]

ALFARO, M. E.; ZOLLER, S.; LUTZONI, F.: Comparative performance of the bootstrap and Bayesian MCMC sampling in assessing phylogenetic confidence: a simulation study The use of Monte Carlo-based Bayesian methods to estimate confidence in phylogenetic results is becoming increasingly common. Although the results of such analyses are often thought to be roughly equivalent to traditional […]

GATESY, J.E.: The Influence of Fossils on the Stability of Phylogenetic Relationships among Extant Taxa: A Preliminary Empirical Assessment in the Age of Genomics The addition of extinct taxa into a phylogenetic analysis can have three consequences for the stability of relationships among extant taxa. The fossils can: 1) stabilize a grouping of extant taxa, […]