A new diverse shark fauna from the Wordian (Middle Permian) Khuff Formation in the interior Haushi‐Huqf area,Sultanate of Oman

Abstract: Chondrichthyans are newly reported from the autochthonous Wordian Khuff Formation (middle Permian), cropping out in well‐exposed, low‐palaeolatitude sections in the interior Haushi‐Huqf area of Oman. The shark remains comprise isolated teeth, dermal denticles and fin spines and have been recovered by processing limestone in buffered acetic acid from bulk rock samples. The fauna consists of mainly ctenacanthiform and hybodontiform taxa, identified as Glikmanius cf. myachkovensis, Glikmanius culmenis sp. nov., Omanoselache hendersoni gen. et sp. nov., Omanoselache angiolinii gen. et sp. nov., cf. Omanoselache sp., Reesodus underwoodi gen et sp. nov., Teresodus amplexus gen. et sp. nov., Gunnellodus bellistriatus, Khuffia lenis gen. et sp. nov., Khuffia prolixa gen. et sp. nov. and Euselachii sp. indet. Additional specimens include rare teeth of the lonchidiid cf. ‘Palaeozoic Genus 1’ sp., of the neoselachian Cooleyella cf. fordi and a further indeterminate neoselachian, of an indeterminate petalodont and of the holocephalan Deltodus aff. mercurei and Solenodus cf. crenulatus. Fin spines add a further two taxa, Nemacanthus sp. and Amelacanthus cf. sulcatus, which have neoselachian affinities and therefore an unclear relationship to the recovered teeth. The occurrence of Nemacanthus within this Wordian fauna represents the oldest record of this taxon and its only known occurrence in the Palaeozoic. Of the remaining genera, Glikmanius has previously been recorded from the Wordian, whereas for all the others, this study represents their youngest known stratigraphic occurrence and first occurrence in Guadalupian (middle Permian) strata. This adds significantly to our knowledge of the global diversity of chondrichthyans preceding the end‐Guadalupian biotic crisis. Palaeogeographically, for all taxa, this study represents the first record from the western fringe of the marine Neotethyan basin, and only Cooleyella was previously known from the southern (Gondwanan) part of the Pangaean continental margin.     

Functional Constraints on the Evolution of Larval Forms of Marine Invertebrates: Experimental and Comparative Evidence

Marine invertebrate larvae are well known for their distinctivebody shapes and elaborate patterns of ciliation. In this studyI take a physically based approach to investigate the functionalconsequences of variations in body shape and patterns of ciliation.With experimental models I demonstrate that shape as well assurface area contributes to drag of larval forms. Based on flowfields around larvae tethered in still water and flowing waterI argue that drag, which acts as a partial tether, may influencehow water is processed and food is captured by cilia. With mechanicalmodels of cilia I show that placement of cilia on the surfacescan influence the effectiveness with which water is moved andthe steepness of the velocity gradient through the ciliary layer.These models indicate that placement of cilia on ridges, atextreme anterior ends, and at extreme posterior ends of larvalbodies increases the volume of water moved per ciliary strokerelative to placement of cilia on a flat surface. A comparativesurvey of46 larval forms indicates that distributions of bodyshape and patterns of ciliation reflect functional requirementsof swimming and feeding by larvae. The experimental and comparativeapproaches together suggest functional constraints on the evolutionof larval forms which may lead to convergence in patterns ofciliation and conservation of larval forms within taxa.     

Entrapped sand as a plant defence: effects on herbivore performance and preference

1. Abrasive material in the diet of herbivorous organisms comes from a variety of sources, including crystalline silica or calcium in plant tissues, accidentally ingested soil while digging or grazing, and entrapped substrate on the surfaces of plants. A wide variety of plants entrap substrate, usually with glandular trichomes. 2. A previous study demonstrated that entrapped sand provided resistance to herbivory in the field. In this study, the following questions were addressed: how does entrapped sand on Abronia latifolia (Nyctaginaceae) leaves and stems affect preference and performance of a common herbivore, the large‐bodied caterpillar Hyles lineata (Sphingidae); does this effect differ from those experienced by an internally feeding leaf miner? 3. Using a combination of experimental and observational approaches, it was found that sand comprised ～4–5% of ingested weight during normal feeding of H. lineata caterpillars. This entrapped sand caused extensive wear to their mandibles, they avoided sand‐covered plants when given the choice, and the sand negatively impacted performance metrics, including pupal weight, development time, and growth rate. In contrast, a leaf‐mining caterpillar did not have a preference for or against feeding on sandy plants. 4. These results are similar to studies on mandibular wear due to grasses, and herbivorous insects that feed on these two plant groups may have similar morphologies. It is hypothesised that increased wear potential may be a convergent solution to abrasive plants in both mammals (hypsodonty) and insects.     

Private Lands Programs and Lessons Learned in Illinois

ABSTRACT State wildlife agencies commonly offer private landowners cost-share and technical assistance to improve habitat, but the cost-effectiveness and long-term outcomes of these efforts are rarely evaluated. In 1998, we began a 3-part, statewide evaluation of the Illinois Department of Natural Resources’ (IDNR; USA) Private Land Wildlife Habitat Management Program (hereafter the program) as it functioned from 1986 to 1996. We sent a mail-back questionnaire to IDNR biologists to collect information on their perceptions of the program. We sent a separate mail-back questionnaire to private landholders who participated in the program to ascertain their demographic profile, motivations for participation, and attitudes regarding the program. We also conducted on-site evaluations of private properties that were managed under the guidance of the program. We conducted our study to 1) assess if the program effectively assisted participants in establishing and maintaining wildlife habitat, and 2) determine factors associated with optimal management of wildlife habitat on private lands to refine the program and improve effectiveness. We found significant differences between participants in their land use priorities and motivations for managing wildlife and in the resources available to participants to establish and maintain habitat. Our results indicate that although financial incentives may increase participation in private lands initiatives, improving technical and material assistance to landholders is essential for maintaining quality wildlife habitat over the long-term.     

Effects of Drought on Partitioning of Nitrogen in Two Wheat Varieties Differing in Drought-tolerance

A model was constructed to describe the translocation and partitioningof nitrogen on the seventh day after anthesis for well-wateredand droughted plants of two wheat varieties (Triticum aestivumL. cv. Warigal and Condor). The glasshouse-grown plants weredetillered so that a simplified model could be derived for themain stem. A 9-d drought treatment was imposed just after anthesisand this coincided with the period of endosperm cell divisionin the grains. Warigal, which had a higher grain yield thanCondor under drought, absorbed up to 15-times more nitrogenand translocated 1.5-fold more nitrogen to the shoot via thexylem. In both varieties, nitrogen redistributed from vegetativeorgans accounted for more than 60 per cent in control and 70per cent in droughted plants of the nitrogen needed for eargrowth. The net loss of nitrogen increased by 4-3 per cent inthe leaves, but decreased by 60 per cent in the stem under drought.Stem and roots appeared to play an important role in the nitrogeneconomy of droughted plants: less nitrogen was translocateddirectly to the grains from the senescing leaves and 40–60per cent more nitrogen was translocated to the roots. Nearlyall the nitrogen reaching the roots in the phloem was reloadedinto the xylem stream and translocated back to the shoot. Thetransfer of nitrogen through the stem was reduced under droughtand this resulted in a constant C:N ratio of the grains whichmay be important in the regulation of endosperm cell division. Triticum aestivum L., wheat, drought, nitrogen, senescence, translocation     

Bridging the morphological and biological species concepts: studies on the Bactrocera dorsalis (Hendel) complex (Diptera: Tephritidae: Dacinae) in South-east Asia

Defining species accurately is a critical need in fundamental disciplines such as ecology and evolutionary biology and in applied arenas such as pest management. The validity of species designations depends on agreement of different methods of species diagnosis for unique biological species. The Bactrocera dorsalis complex of fruit flies provide an excellent opportunity for such a test of the congruence of different techniques (e.g. morphological, molecular, host-plant based, chemotaxonomy) used for species diagnosis. The complex contains a large number of closely-related species, is distributed over a wide geographical range in South-east Asia and considerable information has been compiled on some species. In the present study, the morphological and biological species boundaries were compared using new data from morphometric analyses of reproductive and body parts, together with a review of data on morphology, chemistry of male pheromones that are important in courtship and mating, molecular analyses, and endemic rainforest host plants. For the populations studied ( Bactrocera carambolae , Bactrocera dorsalis , Bactrocera occipitalis , Bactrocera papayae , Bactrocera philippinensis , Bactrocera kandiensis and Bactrocera invadens ) there appears to be significant congruence between the morphological and biological species boundaries.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 217–226.     

Sources of plant-derived carbon and stability of organic matter in soil: implications for global change

Alterations in forest productivity and changes in the relative proportion of above‐ and belowground biomass may have nonlinear effects on soil organic matter (SOM) storage. To study the influence of plant litter inputs on SOM accumulation, the Detritus Input Removal and Transfer (DIRT) Experiment continuously alters above‐ and belowground plant inputs to soil by a combination of trenching, screening, and litter addition. Here, we used biogeochemical indicators [i.e., cupric oxide extractable lignin‐derived phenols and suberin/cutin‐derived substituted fatty acids (SFA)] to identify the dominant sources of plant biopolymers in SOM and various measures [i.e., soil density fractionation, laboratory incubation, and radiocarbon‐based mean residence time (MRT)] to assess the stability of SOM in two contrasting forests within the DIRT Experiment: an aggrading deciduous forest and an old‐growth coniferous forest. In the deciduous forest, removal of both above‐ and belowground inputs increased the total amount of SFA over threefold compared with the control, and shifted the SFA signature towards a root‐dominated source. Concurrently, light fraction MRT increased by 101 years and C mineralization during incubation decreased compared with the control. Together, these data suggest that root‐derived aliphatic compounds are a source of SOM with greater relative stability than leaf inputs at this site. In the coniferous forest, roots were an important source of soil lignin‐derived phenols but needle‐derived, rather than root‐derived, aliphatic compounds were preferentially preserved in soil. Fresh wood additions elevated the amount of soil C recovered as light fraction material but also elevated mineralization during incubation compared with other DIRT treatments, suggesting that not all of the added soil C is directly stabilized. Aboveground needle litter additions, which are more N‐rich than wood debris, resulted in accelerated mineralization of previously stored soil carbon. In summary, our work demonstrates that the dominant plant sources of SOM differed substantially between forest types. Furthermore, inputs to and losses from soil C pools likely will not be altered uniformly by changes in litter input rates.     

History and evolution of alpine plants endemic to the Qinghai-Tibetan Plateau: Aconitum gymnandrum (Ranunculaceae)

How Quaternary climatic oscillations affected range distributions and intraspecific divergence of alpine plants on the Qinghai‐Tibetan Plateau (QTP) remains largely unknown. Here, we report a survey of chloroplast DNA (cpDNA) and nuclear ribosomal internal transcribed spacer (ITS) DNA variation aimed at exploring the phylogeographical history of the QTP alpine endemic Aconitum gymnandrum. We sequenced three cpDNA fragments (rpl20–rps12 intergenic spacer, the trnV intron and psbA‐trnH spacer) and also the nuclear (ITS) region in 245 individuals from 23 populations sampled throughout the species’ range. Two distinct lineages, with eastern and western geographical distributions respectively, were identified from a phylogenetic analysis of ITS sequence variation. Based on a fast substitution rate, these were estimated to have diverged from each other in the early Pleistocene approximately 1.45 Ma. The analysis of cpDNA variation identified nine chlorotypes that clustered into two major clades that were broadly congruent in geographical distribution with the two ITS lineages. The east–west split of cpDNA divergence was supported by an amova which partitioned approximately half of the total variance between these two groups of populations. Analysis of the spatial distribution of chlorotypes showed that each clade was subdivided into two groups of populations such that a total of four population groups existed in the species. It is suggested that these different groups derive from four independent glacial refugia that existed during the Last Glacial Maximum (LGM), and that three of these refugia were located at high altitude on the QTP platform itself at that time. Coalescent simulation of chlorotype genealogies supported both an early Pleistocene origin of the two main cpDNA clades and also the ‘four‐refugia’ hypothesis during the LGM. Two previous phylogeographical studies of QTP alpine plants indicated that such plants retreated to refugia at the eastern/south‐eastern plateau edge during the LGM and/or previous glacial maxima. However, the results for A. gymnandrum suggest that at least some of these cold‐tolerant species may have also survived centrally on the QTP platform throughout the Quaternary.     

The South American catfish genus Auchenipterus Valenciennes, 1840 (Ostariophysi: Siluriformes: Auchenipteridae): monophyly and relationships, with a revisionary study

The Neotropical catfishes of the genus Auchenipterus Valenciennes (1840) are reviewed. The genus is hypothesized to be a monophyletic assemblage on the basis of the shared presence of grooves in the ventral surface of the head that accommodate adducted mental barbels. A possible second synapomorphy, the presence of papillae on the dorsal and medial surface of the ossified maxillary barbel of mature males, is tentatively advanced pending discovery of adult males of three species. Contrary to previous hypotheses which considered Auchenipterus to consist of a maximum of five species, we recognize 11 species, including two previously undescribed forms, A. britskii and A. menezesi: Auchenipterus is broadly distributed through the Rio Orinoco, Rio Amazonas, and Rio de La Plata basins, and the coastal drainages of the Guianas, with one species in the Rio Pindare-Mirim and Rio Parnaiba basins of northeastern Brazil. Auchenipterus nuchalis, previously thought to be broadly distributed across the range of the genus, is found to rather have a restricted distribution in the eastern portions of the Amazon basin, the lower portions of the Rio Tocantins, and lower courses of some rivers in Suriname and French Guiana. Citations of A. nuchalis from elsewhere in the range of the genus are of other species. Euanemus Müller & Troschel (1842) and Ceratocheilus Miranda Ribeiro (1918) are considered synonyms of Auchenipterus. Euanemus colymbetes Müller & Troschel (1842) is considered a synonym of Auchenipterus (fen/ata Valenciennes (1840), and A. paysanduanus Devincenzi (1933) is placed into the synonymy of A. nigripinnis Boulenger (1895). A neotype is designated for Hypopthalmus nuchalis Spix & Agassiz (1829). Lectotypes are designated for Euanemus colymbetes and Auchenipterus nigripinnis.     

Aestivation among ornithopod dinosaurs of the African Trias

Thulborn, Richard A. 1978 07 15: Aestivation among ornithopod dinosaurs of the African Trias. Lethaia . Vol. 11, pp. 185–198. Oslo. ISSN 0024–1164.
Dental and circumstantial evidence supports the theory that ornithopod dinosaurs of the African Red Beds responded to seasonal changes in their environment by resorting to aestivation (dry season dormancy). One group of ornithopods. the heterodontosaurids. apparently suppressed tooth replacement to permit efficient grinding of their plant food and probably replaced their entire cheek dentitions while aestivating. The sympatric fabrosaurid ornithopods had a simple open-and-shut jaw action and replaced their teeth continuously in standard reptilian fashion. Seasonal dormancy must have imposed major constraints on the lives of fabrosaurids and heterodontosaurids. and these constraints are summarized in the model of a circannual life cycle.