Urspelerpes, U. brucei

Number of Pages: 3Integrative BiologyGeological Science

Morphological asymmetry and interspecific hybridization: A case study using hylid frogs

The limited studies addressing developmental stability of interspecific hybrids suggest a positive association between the level of fluctuating asymmetry and 1) the degree of divergence between parental species, and 2) the recency of the contact zone. To evaluate these associations, we examined asymmetry in a recentlyestablished hybrid population of treefrogs (Hyla cinerea and H. gratiosa) that show marked structural gene divergence. Fluctuating asymmetry (FA), directional asymmetry, and antisymmetry were assessed for eight paired osteometric traits in allozymically-defined parental and hybrid categories. FA levels varied considerably among traits. Nonetheless, for any given trait, the hybrid categories did not demonstrate elevated levels of FA compared to the parental categories, or compared to frogs from a non-hybridizing parental population. The only trait that differed statistically among categories (pterygoid length) involved a significantly lower FA value for the Fl hybrids. Thus, observed FA values do not support expectations that the hybrid categories should experience decreased developmental stability

Morphological asymmetry and interspecific hybridization: A case study using hylid frogs

The limited studies addressing developmental stability of interspecific hybrids suggest a positive association between the level of fluctuating asymmetry and 1) the degree of divergence between parental species, and 2) the recency of the contact zone. To evaluate these associations, we examined asymmetry in a recentlyestablished hybrid population of treefrogs (Hyla cinerea and H. gratiosa) that show marked structural gene divergence. Fluctuating asymmetry (FA), directional asymmetry, and antisymmetry were assessed for eight paired osteometric traits in allozymically-defined parental and hybrid categories. FA levels varied considerably among traits. Nonetheless, for any given trait, the hybrid categories did not demonstrate elevated levels of FA compared to the parental categories, or compared to frogs from a non-hybridizing parental population. The only trait that differed statistically among categories (pterygoid length) involved a significantly lower FA value for the Fl hybrids. Thus, observed FA values do not support expectations that the hybrid categories should experience decreased developmental stability

Morphological asymmetry and interspecific hybridization: A case study using hylid frogs

Abstract The limited studies addressing developmental stability of interspecific hybrids suggest a positive association between the level of fluctuating asymmetry and 1) the degree of divergence between parental species, and 2) the recency of the contact zone. To evaluate these associations, we examined asymmetry in a recentlyestablished hybrid population of treefrogs (Hyla cinerea and H. gratiosa) that show marked structural gene divergence. Fluctuating asymmetry (FA), directional asymmetry, and antisymmetry were assessed for eight paired osteometric traits in allozymically-defined parental and hybrid categories. FA levels varied considerably among traits. Nonetheless, for any given trait, the hybrid categories did not demonstrate elevated levels of FA compared to the parental categories, or compared to frogs from a non-hybridizing parental population. The only trait that differed statistically among categories (pterygoid length) involved a significantly lower FA value for the Fl hybrids. Thus, observed FA values do not support expectations that the hybrid categories should experience decreased developmental stability

Coral reef ecology in the Anthropocene

We are in the Anthropocene—an epoch where humans are the dominant force of planetary change. Ecosystems increasingly reflect rapid human-induced, socioeconomic and cultural selection rather than being a product of their surrounding natural biophysical setting. This poses the intriguing question: To what extent do existing ecological paradigms capture and explain the current ecological patterns and processes we observe? We argue that, although biophysical drivers still influence ecosystem structure and function at particular scales, their ability to offer predictive capacity over coupled social–ecological systems is increasingly compromised as we move further into the Anthropocene. Traditionally, the dynamics of coral reefs have been studied in response to their proximate drivers of change rather than their underlying socioeconomic and cultural drivers. We hypothesise this is limiting our ability to accurately predict spatial and temporal changes in coral reef ecosystem structure and function. We propose “social–ecological macroecology” as a novel approach within the field of coral reef ecology to a) identify the interactive effects of biophysical and socioeconomic and cultural drivers of coral reef ecosystems across spatial and temporal scales; b) test the robustness of existing coral reef paradigms; c) explore whether existing paradigms can be adapted to capture the dynamics of contemporary coral reefs; and d) if they cannot, develop novel coral reef social–ecological paradigms, where human dynamics are part of the paradigms rather than the drivers of them. Human socioeconomic and cultural processes must become embedded in coral reef ecological theory and practice as much as biophysical processes are today if we are to predict and manage these systems successfully in this era of rapid change. This necessary shift in our approach to coral reef ecology will be challenging and will require truly interdisciplinary collaborations between the natural and social sciences. A plain language summary is available for this article

Digits Lost or Gained? Evidence for Pedal Evolution in the Dwarf Salamander Complex (Eurycea, Plethodontidae)

Change in digit number, particularly digit loss, has occurred repeatedly over the evolutionary history of tetrapods. Although digit loss has been documented among distantly related species of salamanders, it is relatively uncommon in this amphibian order. For example, reduction from five to four toes appears to have evolved just three times in the morphologically and ecologically diverse family Plethodontidae. Here we report a molecular phylogenetic analysis for one of these four-toed lineages – the Eurycea quadridigitata complex (dwarf salamanders) – emphasizing relationships to other species in the genus. A multilocus phylogeny reveals that dwarf salamanders are paraphyletic with respect to a complex of five-toed, paedomorphic Eurycea from the Edwards Plateau in Texas. We use this phylogeny to examine evolution of digit number within the dwarf−Edwards Plateau clade, testing contrasting hypotheses of digit loss (parallelism among dwarf salamanders) versus digit gain (re-evolution in the Edwards Plateau complex). Bayes factors analysis provides statistical support for a five-toed common ancestor at the dwarf-Edwards node, favoring, slightly, the parallelism hypothesis for digit loss. More importantly, our phylogenetic results pinpoint a rare event in the pedal evolution of plethodontid salamanders