title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=1499 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Gorgonopsian therapsids (Nochnitsa gen. nov. and Viatkogorgon) from the Permian Kotelnich locality of Russia link: https://peerj.com/articles/4954 last-modified: 2018-06-08 description: The early evolution of gorgonopsians is poorly understood. New material from the Kotelnich locality in Russia expands our knowledge of middle/earliest late Permian gorgonopsians from Laurasia. Two gorgonopsian taxa are recognized from Kotelnich: Viatkogorgon ivakhnenkoi Tatarinov, 1999 and Nochnitsa geminidens gen. et sp. nov. Nochnitsa can be distinguished from all known gorgonopsians by its unique upper postcanine tooth row, composed of pairs of teeth (a small anterior and larger posterior) separated by diastemata. Both Viatkogorgon and Nochnitsa are relatively small gorgonopsians, comparable in size to the South African middle Permian taxon Eriphostoma. Inclusion of Viatkogorgon and Nochnitsa in a phylogenetic analysis of gorgonopsians recovers them in basal positions, with Nochnitsa representing the earliest-diverging gorgonopsian genus. All other sampled gorgonopsians fall into two major subclades: one made up entirely of Russian taxa (Inostrancevia, Pravoslavlevia, Sauroctonus, and Suchogorgon) and the other containing only African gorgonopsians. The high degree of endemism indicated in this analysis for gorgonopsians is remarkable, especially given the extensive intercontinental dispersal inferred for coeval therapsid groups. creator: Christian F. Kammerer creator: Vladimir Masyutin uri: https://doi.org/10.7717/peerj.4954 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Kammerer et al. title: Process-based allometry describes the influence of management on orchard tree aboveground architecture link: https://peerj.com/articles/4949 last-modified: 2018-06-08 description: We evaluated allometric relationships in length, diameter, and mass of branches for two variably managed orchard tree species (tart cherry, Prunus cerasus; apple, Malus spp.). The empirically estimated allometric exponents (a) of the orchard trees were described in the context of two processed-based allometry models that make predictions for a: the West, Brown and Enquist fractal branching model (WBE) and the recently introduced Flow Similarity model (FS). These allometric models make predictions about relationships in plant morphology (e.g., branch mass, diameter, length, volume, surface area) based on constraints imposed on plant growth by physical and physiological processes. We compared our empirical estimates of a to the model predictions to interpret the physiological implications of pruning and management in orchard systems. Our study found strong allometric relationships among the species and individuals studied with limited agreement with the expectations of either model. The 8/3-power law prediction of the mass ∼ diameter relationship by the WBE, indicative of biomechanical limitations, was marginally supported by this study. Length-including allometric relationships deviated from predictions of both models, but shift toward the expectation of flow similarity. In this way, managed orchard trees deviated from strict adherence to the idealized expectations of the models, but still fall within the range of model expectations in many cases despite intensive management. creator: Zachary T. Brym creator: S.K. Morgan Ernest uri: https://doi.org/10.7717/peerj.4949 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Brym and Ernest title: A new therocephalian (Gorynychus masyutinae gen. et sp. nov.) from the Permian Kotelnich locality, Kirov Region, Russia link: https://peerj.com/articles/4933 last-modified: 2018-06-08 description: A new therocephalian taxon (Gorynychus masyutinae gen. et sp. nov.) is described based on a nearly complete skull and partial postcranium from the Permian Kotelnich locality of Russia. Gorynychus displays an unusual mixture of primitive (“pristerosaurian”) and derived (eutherocephalian) characters. Primitive features of Gorynychus include extensive dentition on the palatal boss and transverse process of the pterygoid, paired vomers, and a prominent dentary angle; derived features include the absence of the postfrontal. Gorynychus can be distinguished from all other therocephalians by its autapomorphic dental morphology, with roughly denticulated incisors and postcanines. Phylogenetic analysis recovers Gorynychus as a non-lycosuchid, non-scylacosaurid therocephalian situated as sister-taxon to Eutherocephalia. The identification of Gorynychus as the largest predator from Kotelnich indicates that therocephalians acted as apex predators in middle–late Permian transition ecosystems in Russia, corroborating a pattern observed in South African faunas. However, other aspects of the Kotelnich fauna, and Permian Russian tetrapod faunas in general, differ markedly from those of South Africa and suggest that Karoo faunas are not necessarily representative of global patterns. creator: Christian F. Kammerer creator: Vladimir Masyutin uri: https://doi.org/10.7717/peerj.4933 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Kammerer and Masyutin title: Literature-based latitudinal distribution and possible range shifts of two US east coast dune grass species (Uniola paniculata and Ammophila breviligulata) link: https://peerj.com/articles/4932 last-modified: 2018-06-08 description: Previous work on the US Atlantic coast has generally shown that coastal foredunes are dominated by two dune grass species, Ammophila breviligulata (American beachgrass) and Uniola paniculata (sea oats). From Virginia northward, A. breviligulata dominates, while U. paniculata is the dominant grass south of Virginia. Previous work suggests that these grasses influence the shape of coastal foredunes in species-specific ways, and that they respond differently to environmental stressors; thus, it is important to know which species dominates a given dune system. The range boundaries of these two species remains unclear given the lack of comprehensive surveys. In an attempt to determine these boundaries, we conducted a literature survey of 98 studies that either stated the range limits and/or included field-based studies/observations of the two grass species. We then produced an interactive map that summarizes the locations of the surveyed papers and books. The literature review suggests that the current southern range limit for A. breviligulata is Cape Fear, NC, and the northern range limit for U. paniculata is Assateague Island, on the Maryland and Virginia border. Our data suggest a northward expansion of U. paniculata, possibly associated with warming trends observed near the northern range limit in Painter, VA. In contrast, the data regarding a range shift for A. breviligulata remain inconclusive. We also compare our literature-based map with geolocated records from the Global Biodiversity Information Facility and iNaturalist research grade crowd-sourced observations. We intend for our literature-based map to aid coastal researchers who are interested in the dynamics of these two species and the potential for their ranges to shift as a result of climate change. creator: Evan B. Goldstein creator: Elsemarie V. Mullins creator: Laura J. Moore creator: Reuben G. Biel creator: Joseph K. Brown creator: Sally D. Hacker creator: Katya R. Jay creator: Rebecca S. Mostow creator: Peter Ruggiero creator: Julie C. Zinnert uri: https://doi.org/10.7717/peerj.4932 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Goldstein et al. title: MipLAAO, a new L-amino acid oxidase from the redtail coral snake Micrurus mipartitus link: https://peerj.com/articles/4924 last-modified: 2018-06-08 description: L-amino acid oxidases (LAAOs) are ubiquitous enzymes in nature. Bioactivities described for these enzymes include apoptosis induction, edema formation, induction or inhibition of platelet aggregation, as well as antiviral, antiparasite, and antibacterial actions. With over 80 species, Micrurus snakes are the representatives of the Elapidae family in the New World. Although LAAOs in Micrurus venoms have been predicted by venom gland transcriptomic studies and detected in proteomic studies, no enzymes of this kind have been previously purified from their venoms. Earlier proteomic studies revealed that the venom of M. mipartitus from Colombia contains ∼4% of LAAO. This enzyme, here named MipLAAO, was isolated and biochemically and functionally characterized. The enzyme is found in monomeric form, with an isotope-averaged molecular mass of 59,100.6 Da, as determined by MALDI-TOF. Its oxidase activity shows substrate preference for hydrophobic amino acids, being optimal at pH 8.0. By nucleotide sequencing of venom gland cDNA of mRNA transcripts obtained from a single snake, six isoforms of MipLAAO with minor variations among them were retrieved. The deduced sequences present a mature chain of 483 amino acids, with a predicted pI of 8.9, and theoretical masses between 55,010.9 and 55,121.0 Da. The difference with experimentally observed mass is likely due to glycosylation, in agreement with the finding of three putative N-glycosylation sites in its amino acid sequence. A phylogenetic analysis of MmipLAAO placed this new enzyme within the clade of homologous proteins from elapid snakes, characterized by the conserved Serine at position 223, in contrast to LAAOs from viperids. MmipLAAO showed a potent bactericidal effect on S. aureus (MIC: 2 µg/mL), but not on E. coli. The former activity could be of interest to future studies assessing its potential as antimicrobial agent. creator: Paola Rey-Suárez creator: Cristian Acosta creator: Uday Torres creator: Mónica Saldarriaga-Córdoba creator: Bruno Lomonte creator: Vitelbina Núñez uri: https://doi.org/10.7717/peerj.4924 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Rey-Suárez et al. title: ­Characterization of pyruvate kinase from the anoxia tolerant turtle, Trachemys scripta elegans: a potential role for enzyme methylation during metabolic rate depression link: https://peerj.com/articles/4918 last-modified: 2018-06-08 description: BackgroundPyruvate kinase (PK) is responsible for the final reaction in glycolysis. As PK is a glycolytic control point, the analysis of PK posttranslational modifications (PTM) and kinetic changes reveals a key piece of the reorganization of energy metabolism in an anoxia tolerant vertebrate.MethodsTo explore PK regulation, the enzyme was isolated from red skeletal muscle and liver of aerobic and 20-hr anoxia-exposed red eared-slider turtles (Trachemys scripta elegans). Kinetic analysis and immunoblotting were used to assess enzyme function and the corresponding covalent modifications to the enzymes structure during anoxia.ResultsBoth muscle and liver isoforms showed decreased affinity for phosphoenolpyruvate substrate during anoxia, and muscle PK also had a lower affinity for ADP. I50 values for the inhibitors ATP and lactate were lower for PK from both tissues after anoxic exposure while I50 L-alanine was only reduced in the liver. Both isozymes showed significant increases in threonine phosphorylation (by 42% in muscle and 60% in liver) and lysine methylation (by 43% in muscle and 70% in liver) during anoxia which have been linked to suppression of PK activity in other organisms. Liver PK also showed a 26% decrease in tyrosine phosphorylation under anoxia.DiscussionAnoxia responsive changes in turtle muscle and liver PK coordinate with an overall reduced activity state. This reduced affinity for the forward glycolytic reaction is likely a key component of the overall metabolic rate depression that supports long term survival in anoxia tolerant turtles. The coinciding methyl- and phospho- PTM alterations present the mechanism for tissue specific enzyme modification during anoxia. creator: Amanda M.S. Mattice creator: Isabelle A. MacLean creator: Christine L. Childers creator: Kenneth B. Storey uri: https://doi.org/10.7717/peerj.4918 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Mattice et al. title: Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? link: https://peerj.com/articles/4904 last-modified: 2018-06-08 description: BackgroundThe whale shark (Rhincodon typus) is known to aggregate in a number of coastal locations globally, however what causes these aggregations to form where they do is largely unknown. This study examines whether bathymetry is an important driver of coastal aggregation locations for R. typus through bathymetry’s effect on primary productivity and prey availability. This is a global study taking into account all coastal areas within R. typus’ range.MethodsR. typus aggregation locations were identified through an extensive literature review. Global bathymetric data were compared at R. typus aggregation locations and a large random selection of non-aggregation areas. Generalised linear models were used to assess which bathymetric characteristic had the biggest influence on aggregation presence.ResultsAggregation sites were significantly shallower than non-aggregation sites and in closer proximity to deep water (the mesopelagic zone) by two orders of magnitude. Slope at aggregation sites was significantly steeper than non-aggregation sites. These three bathymetric variables were shown to have the biggest association with aggregation sites, with up to 88% of deviation explained by the GLMs.DiscussionThe three key bathymetric characteristics similar at the aggregation sites are known to induce upwelling events, increase primary productivity and consequently attract numerous other filter feeding species. The location of aggregation sites in these key areas can be attributed to this increased prey availability, thought to be the main reason R. typus aggregations occur, extensively outlined in the literature. The proximity of aggregations to shallow areas such as reefs could also be an important factor why whale sharks thermoregulate after deep dives to feed. These findings increase our understanding of whale shark behaviour and may help guide the identification and conservation of further aggregation sites. creator: Joshua P. Copping creator: Bryce D. Stewart creator: Colin J. McClean creator: James Hancock creator: Richard Rees uri: https://doi.org/10.7717/peerj.4904 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Copping et al. title: Actively transcribed and expressed atp8 gene in Mytilus edulis mussels link: https://peerj.com/articles/4897 last-modified: 2018-06-08 description: BackgroundAnimal mitochondrial genomes typically encode 37 genes: 13 proteins, 22 tRNAs and two rRNAs. However, many species represent exceptions to that rule. Bivalvia along with Nematoda and Platyhelminthes are often suspected to fully or partially lack the ATP synthase subunit 8 (atp8) gene. This raises the question as to whether they are really lacking this gene or is this maybe an annotation problem? Among bivalves, Mytilus edulis has been inferred to lack an ATP8 gene since the characterization of its mitochondrial genome in 1992. Even though recent bioinformatic analyses suggested that atp8 is present in Mytilus spp., due to high divergence in predicted amino acid sequences, the existence of a functional atp8 gene in this group remains controversial.ResultsHere we demonstrate that M. edulis mitochondrial open reading frames suggested to be atp8 (in male and female mtDNAs) are actively translated proteins. We also provide evidence that both proteins are an integral part of the ATP synthase complex based on in-gel detection of ATP synthase activity and two-dimensional Blue-Native and SDS polyacrylamide electrophoresis.ConclusionMany organisms (e.g., Bivalvia along with Nematoda and Platyhelminthes) are considered to be lacking certain mitochondrial genes often only based on poor similarity between protein coding gene sequences in genetically closed species. In some situations, this may lead to the inference that the ATP8 gene is absent, when it is in fact present, but highly divergent. This shows how important complementary role protein-based approaches, such as those in the present study, can provide to bioinformatic, genomic studies (i.e., ability to confirm the presence of a gene). creator: Marek Lubośny creator: Aleksandra Przyłucka creator: Beata Śmietanka creator: Sophie Breton creator: Artur Burzyński uri: https://doi.org/10.7717/peerj.4897 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Lubośny et al. title: The first tetrapod from the mid-Miocene Clarkia lagerstätte (Idaho, USA) link: https://peerj.com/articles/4880 last-modified: 2018-06-08 description: The Clarkia lagerstätte (Latah Formation) of Idaho is well known for its beautifully preserved plant fossils as well as a fauna of insects and fish. Here we present the first known tetrapod fossil from these deposits. This specimen, recovered from the lower anoxic zone of the beds, is preserved as a carbonaceous film of a partial skeleton associated with a partial lower incisor and some tooth fragments. The morphology of the teeth indicates that the first tetrapod reported from Clarkia is a rodent. Its skeletal morphology as well as its bunodont and brachydont dentition suggests that it is a member of the squirrel family (Sciuridae). It is a large specimen that cannot be assigned to a known genus. Instead, it appears to represent the first occurrence of a new taxon with particularly gracile postcranial morphology likely indicative of an arboreal ecology. This new specimen is a rare glimpse into the poorly known arboreal mammal fossil record of the Neogene. It supports a greater taxonomic and ecological diversity of Miocene Sciuridae than previously recognized and offers new lines of inquiry in the paleoecological research enabled by the unique preservation conditions of the Clarkia biota. creator: Jonathan J. M. Calede creator: John D. Orcutt creator: Winifred A. Kehl creator: Bill D. Richards uri: https://doi.org/10.7717/peerj.4880 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Calede et al. title: Scan, extract, wrap, compute—a 3D method to analyse morphological shape differences link: https://peerj.com/articles/4861 last-modified: 2018-06-08 description: Quantitative analysis of shape and form is critical in many biological disciplines, as context-dependent morphotypes reflect changes in gene expression and physiology, e.g., in comparisons of environment-dependent phenotypes, forward/reverse genetic assays or shape development during ontogenesis. 3D-shape rendering methods produce models with arbitrarily numbered, and therefore non-comparable, mesh points. However, this prevents direct comparisons. We introduce a workflow that allows the generation of comparable 3D models based on several specimens. Translocations between points of modelled morphotypes are plotted as heat maps and statistically tested. With this workflow, we are able to detect, model and investigate the significance of shape and form alterations in all spatial dimensions, demonstrated with different morphotypes of the pond-dwelling microcrustacean Daphnia. Furthermore, it allows the detection even of inconspicuous morphological features that can be exported to programs for subsequent analysis, e.g., streamline- or finite-element analysis. creator: Martin Horstmann creator: Alexander T. Topham creator: Petra Stamm creator: Sebastian Kruppert creator: John K. Colbourne creator: Ralph Tollrian creator: Linda C. Weiss uri: https://doi.org/10.7717/peerj.4861 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Horstmann et al.