Declining species richness is a global concern; however, the coarse-scale metrics used at regional or landscape levels might not accurately represent the important habitat characteristics needed to estimate species richness. Currently, there exists a lack of knowledge with regard to the spatial extent necessary to correlate remotely sensed habitat metrics to species richness and animal surveys. We provide a protocol for determining the best scale to use when merging remotely sensed habitat and animal survey data as a step towards improving estimates of vertebrate species richness on broad scales. We test the relative importance of fine-resolution habitat heterogeneity and productivity metrics at multiple spatial scales as predictors of species richness for birds, frogs and mammals using a Bayesian approach and a combination of passive monitoring technologies. Model performance was different for each taxonomic group and dependent on the scale at which habitat heterogeneity and productivity were measured. Optimal scales included a 20-m radius for bats and frogs, an 80-m radius for birds and a 180-m radius for terrestrial mammals. Our results indicate that optimal scales do exist when merging remotely sensed habitat measures with ground-based surveys, but they differ between vertebrate groups. Additionally, the selection of a measurement scale is highly influential to our understanding of the relationships between species richness and habitat characteristics.

Translational regulation of mRNAs is crucial for promoting various cellular and developmental processes. Pumilio1 (Pum1) has been shown to play key roles in translational regulation of target mRNAs in many systems of diverse organisms. In zebrafish immature oocytes, Pum1 was shown to bind to cyclin B1 mRNA and promote the formation of cyclin B1 RNA granules. This Pum1-mediated RNA granule formation seemed critical to determine the timing of translational activation of cyclin B1 mRNA during oocyte maturation, leading to activation of maturation/M-phase-promoting factor (MPF) at the appropriate timing. Despite its fundamental importance, the mechanisms of translational regulation by Pum1 remain elusive. In this study, we examined the phosphorylation of Pum1 as a first step to understand the mechanisms of Pum1-mediated translation. SDS-PAGE analyses and phosphatase treatments showed that Pum1 was phosphorylated at multiple sites during oocyte maturation. This phosphorylation began in an early period after induction of oocyte maturation, which preceded the polyadenylation of cyclin B1 mRNA. Interestingly, depolymerization of actin filaments in immature oocytes caused phosphorylation of Pum1, disassembly of cyclin B1 RNA granules, and polyadenylation of cyclin B1 mRNA but not translational activation of the mRNA. Overexpression of the Pum1 N-terminus prevented the phosphorylation of Pum1, disassembly of cyclin B1 RNA granules, and translational activation of the mRNA even after induction of oocyte maturation. These results suggest that Pum1 phosphorylation in the early period of oocyte maturation is one of the key processes for promoting the disassembly of cyclin B1 RNA granules and translational activation of target mRNA.

Somatic cells derived from zebrafish haploid larval (both androgenetic and gynogenetic) cultures were used as donors for nuclear transplant into non-enucleated oocytes. Nuclei were transplanted either before or simultaneously with oocyte activation in the central region and in the incipient animal pole, respectively. Against expected results, 20% of transplanted embryos during oocyte activation using cells of gynogenetic origin reached the 100% epiboly stage, even two survived for up to 5 days, whereas no development was observed when cells from androgenetic origin were used. Results derived from this work open a novel possibility of studying somatic cell reprogramming and imprinting phenomena in zebrafish.

Species of Protopolystoma are monogenean flukes that only infect allopolyploid hosts in the anuran genus Xenopus. Multivariate analyses of morphometric sclerite characters in the nominal species Protopolystoma simplicis suggest that morphologically distinguishable populations occur in the tetraploid host, Xenopus laevis victorianus, and in each of the octoploid hosts, X. vestitus and X. wittei. The species-level divergence of a lineage specific to X. laevis is supported by sequence variation in the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Protopolystoma simplicis from X. laevis is redesignated P. microsclera n. sp., with P. simplicis being retained for populations in octoploid hosts. This division is consistent with large differences in egg hatching schedule, fixed differences at the mannose-6-phosphate isomerase and fumarate hydratase loci, and host-specificity in experimental analyses. Although the respective P. simplicis populations in X. vestitus and X. wittei also show significant diversity in allozyme expression, morphometrics and egg hatching schedule, they are retained in the same species because their level of mitochondrial DNA divergence is similar to that found within other Protopolystoma species. The consequences of splitting P. simplicis for a recent interpretation of the origin of Protopolystoma faunas in octoploid Xenopus spp. is discussed.

Distortion of the vertebral column in fossils can be used for the estimation of two-dimensional finite strain by a simple geometrical technique, namely the Wellman method. We demonstrate application of the Wellman method to the distorted vertebral columns of a reptile and a stem-chordate, and use the results to restore the undistorted fossil shapes by a computer graphic method. The Wellman method is particularly efficient in situations where independent evidence for the principal strain directions, or undistorted forms, are lacking. The method is purely geometrical, easy to use, and rapid. It involves relatively low error, and works even when only a small segment of the distorted vertebral column is preserved.

Diet was manipulated in juveniles of the snake Boa constrictor (Serpentes: Boidae) to test the hypothesis of whether prey size induces phenotypic plasticity of the head skeleton. Additionally, the onset of sexual size dimorphisms (SSDs) was determined under a feeding schedule where total prey mass consumed by snakes was held constant. Twenty-three neonatal B. constrictor from a single-sired litter were placed into two treatment groups but maintained under identical environmental conditions. Group 1 (small-food treatment) was fed weanling mice throughout the entire study; group 2 (large-food treatment) was fed weanling mice, followed by rats of increasing size as the size of the snakes increased. At the termination of the study, group 1 consumed more meals but both groups consumed an equivalent mass of rodents. The snakes were measured twice during the study (5 weeks and 58 weeks). All measurements were obtained while the snakes were under general anaesthesia. Linear measurements of the head skeleton (premaxilla–basioccipital (rostrum–occipital) length, ROL; mandible length, ML) were derived from radiographs. The remaining measurements were snout–vent length (SVL), body length (BL), tail length (TL), and body mass (BM). Treatment effects between groups were equivalent, with the exception of BM and TL (group 1>group 2), and interactions between main effects were not statistically significant. Between-group differences in ROL and ML were not significant; thus, prey size did not exert an influence on growth of the head skeleton. In contrast, significant sex effects on SVL and BL (females>males) and TL (males>females) were detected, and sex effects on BM (females>males) approached significance. Because SSDs emerged during early ontogeny under conditions where prey mass consumed was held constant, a genetic role is implicated.

Emerging developmental studies contribute to our understanding of vertebrate evolution because changes in the developmental process and the genes responsible for such changes provide a unique way for evaluating the evolution of morphology. Endoskeletal limbs, the locomotor organs that are unique to vertebrates, are a popular model system in the fields of palaeontology and phylogeny because their structure is highly visible and their bony pattern is easily preserved in the fossil records. Similarly, limb development has long served as an excellent model system for studying vertebrate pattern formation. In this review, the evolution of vertebrate limb development is examined in the light of the latest knowledge, viewpoints and hypotheses.

The pectoral girdle articulates the forelimb with the axial skeleton in all vertebrates with paired anterior appendages. The structure of the pectoral girdle and its position along the axial skeleton has changed significantly during vertebrate evolution. These morphological changes have been well described, but there is little comparative embryology to indicate how these changes may have occurred. It is equally obscure how the muscles that connect the head with the pectoral girdle have maintained appropriate attachments even though these 2 structures have become separated. Here I review the changes in the pectoral girdle across different vertebrate taxa, indicating, where known, the developmental mechanisms underlying these changes. I also suggest how the muscular connections between the head and pectoral girdle have been maintained between these once adjacent bones, displaced during vertebrate evolution.

Little is known regarding the internal anatomy of thelodonts, with most of the available information coming from a single specimen, the holotype of Turinia pagei (Powrie). Previous descriptions have led to many partial, or conflicting interpretations. Herein, we describe fully the anatomy of T. pagei based on the holotype and additional material. T. pagei possessed a branchial system composed of eight pairs of gills, a buccal/nasohypophyseal region lined with minute denticles, comparable to buccopharyngeal denticles of sharks, and possessed a stomach which is preserved by sediment infill in the holotype specimen. Contrast between the petrological character of the gut infill and the sediment in which the animal is preserved suggests that the gut was infilled in vivo and that T. pagei was probably a deposit feeder. Phylogenetic analysis resolves T. pagei and the Galeaspida as sister-taxa, comprising a sister-group to the Osteostraci plus jawed vertebrates. In contrast to the view that has prevailed hitherto, thelodonts with a dorsoventrally compressed cross-sectional profile comprise a monophyletic group, of which T. pagei is the least derived member. The furcacaudiforms are resolved as an unnatural group, one taxon being the sister taxon to the ‘conventional’ thelodont clade, and the other, the sister taxon to this clade plus galeaspids, osteostracans and jawed vertebrates. The analysis agrees with the earlier view that thelodonts lack distinct synapomorphies, but we argue that distinct synapomorphies are not a requisite of monophyly.

Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kovács–Endrödy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sufficient evidence exists to justify interpretation of the conodonts on a chordate model. A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon. Various experiments with character coding, taxon deletion and the use of constraint trees are carried out. We conclude that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata. We discuss the evolution of the nervous and sensory systems and the skeleton in the context of our optimal phylogenetic tree. There appears to be no simple evolution of free to canal-enclosed neuromasts; organised neuromasts within canals appear to have arisen at least three times from free neuromasts or neuromasts arranged within grooves. The mineralised vertebrate skeleton first appeared as odontodes of dentine or dentine plus enamel in the paraconodont/euconodont feeding apparatus. Bone appeared later, co-ordinate with the development of a dermal skeleton, and it appears to have been primitively acellular. Atubular dentine is more primitive than tubular dentine. However, the subsequent distribution of the different types of dentine (e.g. mesodentine, orthodentine), suggests that these tissue types are homoplastic. The topology of relationships and known stratigraphic ranges of taxa in our phylogeny predict the existence of myxinoids and petromyzontids in the Cambrian.

Views of the Late Roman period in England have changed considerably in the past few years, with a tendency towards acceptance of a survival or resurgence of economic and political organization despite earlier decline. Traditional evidence provides some insights into the differential nature of these changes. Here it is argued that ‘environmental’ (in this case biological) evidence can provide unique insights into economic systems, and that bones and insects from late 4th-century AD Lincoln indicate continuity of complex systems into this period.