A Late Miocene Paratethyan mollusc fauna from the Denizli Basin (southwestern Anatolia, Turkey) and its regional palaeobiogeographic implications

We report on a Late Miocene mollusc fauna from a single locality in the Denizli Basin in southwestern Turkey that is composed of ten presumably euryhaline species and three freshwater species. The fauna is remarkably distinct from faunas of the adjacent Late Miocene Aegean and Euxinian Basins, and has elements in common with the modern Caspian Sea fauna in the form of Didacna species. The suggested age of the fauna (Late Miocene) would extend the stratigraphic range of the lymnocardiid genus Didacna (hitherto Calabrian-Extant) considerably. The palaeobiogeographic significance of the Denizli fauna is discussed.     

A new species of Malaxis (Orchidaceae) from Guerrero, Mexico

Malaxis molotensis, a new orchid species from a wet cloud forest of the Sierra Madre del Sur, Guerrero, Mexico is described and illustrated. In habit and floral structure it resembles the widespread M. histionantha but differs in the elliptic labellum with incurved distal margin, and elongate, oblong-falciform pollinaria.     

Influences of biological interactions on community structure within seagrass beds and sandprawn-dominated sandflats

The faunal composition of high-shore beds of eelgrass Zostera capensis versus unvegetated sandflats dominated by the sandprawn Callianassa kraussi was investigated by experimentally transplanting plots of eelgrass into sandflats where the sandprawn was either left unmanipulated or eliminated by prior faunal suffocation. After 12 months, multidimensional scaling defined five faunal clusters that were dictated primarily by the presence or absence of eelgrass rather than sandprawns. By 18 months, eelgrass and sandprawns played equal roles in defining faunal clusters. After 30 months, sandprawns had displaced the eelgrass transplants and faunal composition converged on that of sandflat control plots.Most species were either ‘eelgrass-associated’ or ‘sandflat-associated’, but three had unique responses to the treatments: two high-shore species (Assiminea globulus and Hydrobia sp.) that were abundant in eelgrass beds never appeared in the eelgrass transplants, whereas another eelgrass-occupant, Siphonaria compressa, became superabundant on the transplants for 18 months.Unexpectedly, the eelgrass fauna was never more rich or diverse than that of unvegetated sandflats, although abundance was greater in the eelgrass. As hypothesised, the sandflats were disproportionally populated by burrowers and eelgrass by non-burrowers, but a second hypothesis that these habitats should support mainly hard-bodied and soft-bodied animals respectively was rejected.The distinctively different faunas of eelgrass and unvegetated sandflats are seemingly respectively maintained by sediment stabilisation by eelgrass versus bioturbation by sandprawns. The transplants of eelgrass into sandflats developed an eelgrass-associated fauna provided sandprawns were excluded, but ultimately reverted to a sandflat fauna once sandprawns reinvaded.     

Predation activity of two winter-active spiders (Araneae: Anyphaenidae,Philodromidae)

Anyphaena accentuata and Philodromus spp. are cold adapted and winter-active spider species. Their predation activity was investigated at constant temperatures between –4 and 30 °C. The lower temperature threshold for Anyphaena was –3.7 °C, while that of Philodromus was –1.2 °C. At 1 °C the latency to capture and prey consumption was significantly shorter in Anyphaena than in Philodromus. The capture rate increased with temperature and was maximal at 15 °C in Anyphaena and at 30 °C in Philodromus. At 30 °C, the latency to the capture was significantly shorter in Philodromus than in Anyphaena whose mortality significantly increased.     

Seasonal acclimation in resting metabolism of the skink, Mabuya brevicollis (Reptilia: Scincidae) from southwestern Saudi Arabia

The resting metabolic rate (RMR) of seasonally-acclimated Mabuya brevicollis of various body masses was determined at 20, 25, 30, 35 and 40 °C, using open-flow respirometry. RMR (ml g⁻¹ h⁻¹) decreased with increasing mass at each temperature. RMRs increaProd. Type: FTPsed as temperature increased. The highest and lowest Q₁₀ values were obtained for the temperature ranges 20–25 °C and 30–35 °C for the summer-acclimated lizards. The exponent of mass “b” in the metabolism-body mass relation ranged from 0.41 to 0.61. b values were lower in the autumn and winter-acclimated lizards than in spring and summer-acclimated lizards. Seasonal acclimation effects were evident at all temperatures (20–40 °C) for M. brevicollis. Winter-acclimated skinks had the lowest metabolic rates at different temperatures. The pattern of acclimation exhibited by M. brevicollis may represent a useful adaptation for lizards inhabiting subtropical deserts to promote activity during their active seasons.     

Condition,growth and food conversion in barbel, Barbus barbus (L.) juveniles under different temperature/diet combinations

Populations of a rheophilic cyprinid Barbus barbus have declined in last decades, which created a need of conservation aquaculture. Production of stocking material in controlled conditions calls for optimization of the two major factors, temperature and diet. Condition, growth and food conversion ratio in fish fed a formulated diet Aller Futura were compared with those on natural food—frozen Chironomidae larvae at 17, 21 and 25 °C. Groups of 60 early juveniles (0.6–3.7 g) were reared in each of 18 aquaria in which six experimental groups were run in triplicate. Daily food ratios were adjusted according to fish biomass, differences in hydration between the two diets and rearing temperature. No mortality occurred during the experiment. Condition coefficient K was significantly higher in fish fed Aller Futura compared to those fed Chironomidae irrespective of temperature tested; body deformities were not recorded. Relative growth rate at the same temperature was always higher in fish on the formulated diet than in those fed Chironomidae, and food conversion ratio was always suppressed, both suggesting an efficient utilization of Aller Futura for growth in B. barbus early juveniles. On both diets the coefficient K was depressed at 21 °C. Relative growth rate (RGR) was accelerated with temperature according the Krogh’s “normal curve” within the range 21–25 °C, while at lower temperatures (17–21 °C) the observed values of temperature coefficient Q₁₀ were much higher than the theoretical Q₁₀ values based on Krogh’s “normal curve”. Food conversion ratios (FCR) were reduced on both diets at 21 and 25 °C. Theoretical optimum temperatures for food conversion were 22.0 and 23.6 °C. Summing up, responses of three independent indices: condition, growth and food utilization locate the optimum temperature for B. barbus between 21 and 25 °C. No evidence was found that the effect of temperature on these indices was substantially modified by the diet.     

Effect of water temperature,salinity, and their interaction on growth,plasma osmolality,and gill Na,K-ATPase activity in juvenile GIFT tilapia Oreochromis niloticus (L.)

We used a central composite rotatable experimental design and response surface methodology to evaluate the effects of temperature (18–37 °C), salinity (0–20‰), and their interaction on specific growth rate (SGR), feed efficiency (FE), plasma osmolality, and gill Na⁺, K⁺-ATPase activity in GIFT tilapia juveniles. The linear and quadratic effects of temperature and salinity on SGR, plasma osmolality, and gill Na⁺, K⁺-ATPase activity were statistically significant (P<0.05). The interactive effects of temperature and salinity on plasma osmolality were significant (P<0.05). In contrast, the interaction term was not significant for SGR, FE, and gill Na⁺, K⁺-ATPase activity ⁽P>0.05). The regression equations for SGR, FE, plasma osmolality, and gill Na⁺, K⁺-ATPase activity against the two factors of interest had coefficients of determination of 0.944, 0.984, 0.966, and 0.960, respectively (P<0.01). The optimal temperature/salinity combination was 28.9 °C/7.8‰ at which SGR (2.26% d¹) and FE (0.82) were highest. These values correspond to the optimal temperature/salinity combination (29.1 °C/7.5‰) and the lowest plasma osmolality (348.38 mOsmol kg⁻¹) and gill Na⁺, K⁺-ATPase activity (1.31 µmol Pi. h⁻¹ g⁻¹ protein), and resulted in an energy-saving effect on osmoregulation, which promoted growth.     

Şerefköy-2, a new Late Miocene mammal locality from the Yatağan Formation,Muğla,SW Turkey

Here we report on a new fossil locality, ?erefköy-2, from the Yata?an Basin of southwestern Turkey that preserves a well-sampled, abundant, and diverse mammal fauna. Indeed, after three field seasons, more than 1200 catalogued specimens representing 26 mammal species belonging to 14 genera make the ?erefköy-2 mammalian assemblage one of the richest Late Miocene fauna from Anatolia. Five hipparionines, six bovids, including the rare and enigmatic Urmiatherium rugosifrons and the presence of Pliohyrax graecus, strongly support affinities with Late Miocene faunas from Samos Island, Greece. Through a consideration of the identified material and the subsequent comparison with material from well-known Balkan and Anatolian faunas, a Middle Turolian (MN12) age for ?erefköy-2 is indicated.     

Phylogeography of the bark beetle Dendroctonus mexicanus Hopkins (Coleoptera: Curculionidae: Scolytinae)

Dendroctonus mexicanus is polyphagous within the Pinus genus and has a wide geographical distribution in Mexico and Guatemala. We examined the pattern of genetic variation across the range of this species to explore its demographic history and its phylogeographic pattern. Analysis of the mtDNA sequences of 173 individuals from 25 Mexican populations allowed to us identify 53 geographically structured haplotypes. High haplotype and low nucleotide diversities and Tajima’s D indicate that D. mexicanus experienced rapid population expansion during its dispersal across mountain systems within its current range. The nested clade phylogeographic analysis indicates that the phylogeographic pattern of D. mexicanus is explained by continuous dispersion among lineages from the Sierra Madre Occidental, the Sierra Madre Oriental and the Trans-Mexican Volcanic Belt. However, we also observed isolation events among haplotypes from the Cofre de Perote/Trans-Mexican Volcanic Belt/Sierra Madre Oriental and the Trans-Mexican Volcanic Belt/Sierra Madre del Sur, which is consistent with the present conformation of mountain systems in Mexico and the emergence of geographical barriers during the Pleistocene.     

Larsenia salina gen. nov., sp. nov., a new member of the family Halomonadaceae based on multilocus sequence analysis

Two Gram-staining-negative, moderately halophilic bacteria, strains M1-18^T and L1-16, were isolated from a saltern located in Huelva (Spain). They were motile, strictly aerobic rods, growing in the presence of 3–25% (w/v) NaCl (optimal growth at 7.5–10% [w/v] NaCl), between pH 4.0 and 9.0 (optimal at pH 6.0–7.0) and at temperatures between 15 and 40 °C (optimal at 37 °C). Phylogenetic analysis based on 16S rRNA gene sequence comparison showed that both strains showed the higher similarity values with Chromohalobacter israelensis ATCC 43985^T (95.2–94.8%) and Chromohalobacter salexigens DSM 3043^T (95.0–94.9%), and similarity values lower than 94.6% with other species of the genera Chromohalobacter, Kushneria, Cobetia or Halomonas. Multilocus sequence analysis (MLSA) based on the partial sequences of atpA, rpoD and secA housekeeping genes indicated that the new isolates formed an independent and monophyletic branch that was related to the peripheral genera of the family Halomonadaceae, Halotalea, Carnimonas and Zymobacter, supporting their placement as a new genus of the Halomonadaceae. The DNA–DNA hybridization between both strains was 82%, whereas the values between strain M1-18^T and the most closely related species of Chromohalobacter and Kushneria were equal or lower to 48%. The major cellular fatty acids were C_18:1ω7c/C_18:1ω6c, C_16:0, and C_16:1ω7c/C_16:1ω6c, a profile that differentiate this new taxon from species of the related genera. We propose the placement of both strains as a novel genus and species, within the family Halomonadaceae, with the name Larsenia salina gen. nov., sp. nov. The type strain is M1-18^T (= CCM 8464 = CECT 8192^T = IBRC-M 10767^T = LMG 27461^T).     

Creodonts and carnivores from the Middle Miocene Muruyur Formation at Kipsaraman and Cheparawa,Baringo District,Kenya

The Middle Miocene Muruyur Formation (ca 14.5 Ma), Tugen Hills, Kenya, has yielded a huge creodont and a variety of carnivores ranging in size from mongoose-sized viverrids and herpestids to lion-sized amphicyonids. The fauna partly fills what used to be a major gap in our knowledge of Neogene African carnivores, spanning the period between the better known Early Miocene assemblages of western Kenya and eastern Uganda, and the Late Miocene and Plio–Pleistocene faunas of East Africa. Present in the deposits are Megistotherium, two species of Hecubides, one species of Agnotherium, Herpestes, Vishnuictis, and one or two undetermined felids.     

Evaporative water loss and energy metabolic in two small mammals,voles (Eothenomys miletus) and mice (Apodemus chevrieri), in Hengduan mountains region

Evaporative water loss (EWL) and energy metabolism were measured at different temperatures in Eothenomys miletus and Apodemus chevrieri in dry air. The thermal neutral zone (TNZ) of E. miletus was 22.5–30 °C and that of A. chevrieri was 20–27.5 °C. Mean body temperatures of the two species were 35.75±0.5 and 36.54±0.61 °C. Basal metabolic rates (BMR) were 1.92±0.17 and 2.7±0.5 ml O₂/g h, respectively. Average minimum thermal conductance (C_m) were 0.23±0.08 and 0.25±0.06 ml O₂/g h °C. EWL in E. miletus and A. chevrieri increased with the increase in temperature; the maximal EWL at 35 °C was 4.78±0.6 mg H₂O/g h in E. miletus, and 5.92±0.43 mg H₂O/g h in A. chevrieri. Percentage of evaporative heat loss to total heat production (EHL/HP) increased with the increase in temperature; the maximal EHL/HP was 22.45% at 30 °C in E. miletus, and in A. chevrieri it was 19.96% at 27.5 °C. The results may reflect features of small rodents in the Hengduan mountains region: both E. miletus and A. chevrieri have high levels of BMR and high levels of total thermal conductance, compared with the predicted values based on their body masses, while their body temperatures are relatively low. EWL plays an important role in temperature regulation.     

Late Pleistocene and Holocene chitons (Mollusca, Polyplacophora) from Uruguay: Palaeobiogeography and palaeoenvironmental reconstruction in mid latitudes of the southwestern Atlantic

Here we present a revision of the fossil record of chitons (Mollusca, Polyplacophora) of Late Pleistocene and Holocene marine deposits of Uruguay and discuss their potential for palaeoenvironmental reconstruction. Chitons were recorded as isolated valves in bivalve- and gastropod-rich assemblages. They are represented by the species Chaetopleura angulata (Spengler), C. isabellei (d’Orbigny), C. asperrima (Gould) and Ischnochiton striolatus (Gray). The last two species are recorded for the first time as fossils not only in Uruguay but also in South America. Exclusively recorded for the Late Pleistocene is the warm water species I. striolatus, whose current southern range limit is located in Santa Catarina, Brazil. Higher temperatures than at present are inferred for the Uruguayan coast during the Late Pleistocene, probably driven by the southward influence of the warm Brazilian Current along the eastern margin of South America. Chitons from Holocene deposits show a wider geographic distribution along the Uruguayan coast in comparison to current distributions. They are recorded where an estuarine and eurihaline fauna lives today, which suggests the former existence of marine conditions. This is explained by the westward displacement of the marine front in the Uruguayan coast during the Holocene transgressive events. Chitons have proven to be useful palaeoenvironmental proxies for the reconstruction of salinity and temperature trends in the Uruguayan coast during the climatic oscillations of the Late Pleistocene and Holocene epochs. As such, their patterns of distribution are related to the recent physical evolution of the Southwestern Atlantic Ocean.     

Effects of UV radiation and nitrate limitation on the production of biogenic sulfur compounds by marine phytoplankton

We tested the effects of UV radiation (UVR) and nitrate limitation on the production of dimethylsulfide (DMS), particulate dimethylsulfoniopropionate (DMSPp), and particulate dimethylsulfoxide (DMSOp) in natural seawater from the Gulf of Mexico and in phytoplankton cultures. DMS/Chl a ratios in PAR-only and PAR + UV-exposed seawater were 0.44–2.0 and 0.46–1.9 nmol DMS μg⁻¹ Chl a, respectively, whereas the ratios in cultures of Amphidinium carterae were 1.0–2.2 nmol μg⁻¹ in PAR-exposed samples and 0.91–2.1 nmol μg⁻¹ in PAR + UV-exposed samples. These results suggested that UVR did not substantially affect DMS/Chl a ratios in seawater and A. carterae culture samples. Similarly, UVR had no significant effect on DMSOp/Chl a in seawater samples (0.83–1.6 nmol DMSO μg⁻¹ Chl a for PAR + UV vs. 0.70–1.5 nmol μg⁻¹ for PAR-exposed seawater samples, respectively) or in A. carterae cultures (0.20–1.3 and 0.19–0.88 nmol DMSO μg⁻¹ Chl a in PAR + UV- and PAR-exposed cultures, respectively). In an experiment with the diatom, Thalassiosira oceanica, the culture was grown in high nitrate (30 μM) or low nitrate (6 μM) media and exposed to PAR-only or PAR + UV. The low nitrate, PAR-only samples showed an increase of intracellular dimethylsulfoniopropionate (DMSP) concentration from 2.1 to 15 mmol L⁻¹ in 60 h, but the increase occurred only after cultures reached the stationary phase. Cultures of T. oceanica grown under UVR had lower growth rates than those under PAR-only (μ′ = 0.17 and 0.32 d⁻¹, respectively) and perhaps did not experience severe nitrate limitation even in the low nitrate treatment. These results suggest that the elevated UVR in low nitrate environments could result in reduction of DMSP in some species, whereas DMSP concentrations would not be affected in eutrophic areas.     

Further evidence for the presence of holoptychiid porolepiforms (Sarcopterygii,Dipnomorpha) from the Frasnian of Colombia

The Devonian (Frasnian) of Colombia has provided important information on the taxonomical diversity and palaeobiogeographic relationships of the Late Devonian marginal marine vertebrate faunas of South America (northwestern margin of Gondwana). This fauna is mostly composed of Gondwanan endemics, but includes two taxa also known in Euramerica: the antiarchan placoderm Asterolepis and the porolepiform sarcopterygian Holoptychius. The occurrence of holoptychiid porolepiforms in Colombia was previously suggested based solely on the presence of scales attributed to Holoptychius, although with caution. Here, we describe further holoptychiid remains that include a large isolated tooth with dendrodont microstructure, typical of porolepiforms, and additional Holoptychius scales. These new findings increase the record of holoptychiid porolepiform occurrences in Gondwana and suggest that dispersion of fish faunas between Euramerica and Gondwana by the beginning of the Late Devonian was possible through South America.     

Changhsingian (Late Permian) foraminifers from the topmost part of the Xiala Formation in the Tsochen area,central Lhasa Block,Tibet and their geological implications

A foraminiferal fauna consisting of 15 genera and 19 species is documented for the first time from the topmost part of the Xiala Formation in the Aduogabu area in Tsochen County, central Lhasa Block. This foraminiferal fauna is dominated by Colaniella, indicating a broadly Changhsingian age. The presence of Colaniella, Reichelina and absence of the typical tropical fusuline genus Palaeofusulina in the fauna indicate that the Lhasa Block has not merged into equatorial regions during the Changhsingian. More importantly, the widespread Lopingian (Late Permian) marine carbonates with warm-water faunas and the stable platform carbonate sequence through the Guadalupian and Lopingian in the Lhasa Block present an obvious contrast against the contemporaneous sequences in the South Qiangtang Block and Gondwana margin. It suggests that both the Bangong-Nujiang Ocean and the Neotethys Ocean would have opened by the Guadalupian and Lopingian.     

Biometry of Upper Cretaceous (Cenomanian–Maastrichtian) coccoliths – a record of long-term stability and interspecies size shifts

Biometric measurements of Mesozoic coccoliths (coccolith length and width) have been used in short-term biostratigraphic, taxonomic and palaeoecologic studies, but until now, not over longer time scales. Here, we present a long time-series study (∼ 30 million years) for the Upper Cretaceous, which aims to identify broad trends in coccolith size and to understand the factors governing coccolith size change over long time scales. We have generated biometric data for the dominant Upper Cretaceous coccolith groups, Broinsonia/Arkhangelskiella, Prediscosphaera, Retecapsa and Watznaueria, from 36 Cenomanian–Maastrichtian (100.5–66 Ma) samples from Goban Spur in the northeast Atlantic (DSDP Site 549). These data show that the coccolith sizes within Prediscosphaera, Retecapsa and Watznaueria were relatively stable through the Late Cretaceous, with mean size variation less than 0.7 μm. Within the Broinsonia/Arkhangelskiella group there was more pronounced variation, with a mean size increase from ∼ 6 μm in the Cenomanian to ∼ 10 μm in the Campanian. This significant change in mean size was largely driven by evolutionary turnover (species origination and extinctions), and, in particular, the appearance of larger species/subspecies (Broinsonia parca parca, Broinsonia parca constricta, Arkhangelskiella cymbiformis) in the early Campanian, replacing smaller species, such as Broinsonia signata and Broinsonia enormis. Shorter-term size fluctuations within Broinsonia/Arkhangelskiella, observed across the Late Cenomanian–Turonian and Late Campanian–Maastrichtian intervals, may, however, reflect changing palaeoenvironmental conditions, such as sea surface temperature and nutrient availability.     

High allozyme diversity and unidirectional linear migration patterns within a population of tetraploid Isoetes sinensis, a rare and endangered pteridophyte

Isoetes sinensis (Isoetaceae), an aquatic quillwort which occurs only in two fragmented sites of China as an allotetraploid, is critically endangered. Genetic variation among eight subpopulations of I. sinensis was examined in the Xin’an River (119°14′–15′E, 29°28′N) by using allozyme polymorphism. Eighteen loci of 10 enzyme systems were examined and used for the analysis of population genetic parameters. As expected for allotetraploids, fixed heterozygosity was found at four loci. A high level of genetic diversity was observed in the population, with mean number of alleles per loci of 1.8, and mean percentage of polymorphic loci of 55.6%, which were much higher than the average values in fern species. The genetic variation within each subpopulation was not positively correlated with its size, which may be explained by high gene flow (Nm = 2.57), clonal reproduction and fixed heterozygosity of allopolyploid. The I. sinensis population contained high clonal diversity (PD = 0.39, D = 0.95), indicating the successful seedling recruitment of the population. Significant positive relationship was detected between clonal diversity and the size of subpopulation. Partitioning the genetic diversity indicated that 91.1% of the genetic variation was within subpopulations and only 8.9% existed among subpopulations. The migration pattern of I. sinensis along the Xin’an River is best explained by a source–sink model, but with unidirectional gene flow among subpopulations underlined by hydrochoric force. The results were then discussed in relation to both in situ and ex situ conservation efforts of the population.     

Echinoid fauna from a Late Oligocene (Chattian) reef at Damon Mound,Brazoria County,Texas

The echinoid fauna collected from the Late Oligocene (Chattian) reef at Damon Mound, Brazoria County, Texas, includes at least seven species. The reef can be divided into four zones, in ascending order: reef drape, Porites thicket, reef core, and back-reef. The reef drape represents the deepest water and includes the echinoid species Clypeaster marinanus, Agassizia mossomi, and Lovenia alabamensis. The overlying zone consists of interbedded calcilutites and Porites coral thickets, and includes the species Echinometra prisca, C. marinanus, Clypeaster cf. oxybaphon, and Brissus exiguus. The reef core includes Prionocidaris cojimarensis and E. prisca. The shallow back-reef deposits include only C. marinanus. The Damon Mound fauna is more closely related to tropical Oligocene faunas of Mexico and the Antilles than to Gulf and Atlantic Coast faunas of the United States of the same latitude. During the Oligo-Miocene, Damon Mound and similar salt dome reef buildups in the northwestern Gulf of Mexico may have been havens for tropical species that could not have otherwise survived at that latitude.     

Isolation,purification and characterization of phytase from germinating mung beans

Phytase isolated from mung bean cotyledons was purified about 80-fold with a recovery of 28%. The enzyme is stable at 0°, has a pH optimum at 7·5 and optimal temperature of 57°. The energy of activation is approximately 8500 cal/mole between 37° and 57°. Inhibition by P_i has been found to be competitive, the K_i value being 0·40–0·43 × 10⁻³ M; the K_m value with phytate is 0·65 × 10⁻³ M. Divalent cations are not required for activity. Lower members of inositol phosphates are better substrates, as shown by their V_max and K_m values. When subjected to polyacrylamide gel electrophoresis two bands have been resolved; one (major) corresponds to phytase and the other (minor) to phosphatase and pyrophosphatase activity. Filtration through Biogel P-200 partially resolves phytase from phosphatase and pyrophosphatase. The molecular weight of phytase is approximately 160,000.