New remains of Egatochoerus jaegeri (Mammalia,Suoidea) from the late Eocene of Peninsular Thailand

Abstract: We report here additional remains referred to Egatochoerus jaegeri from the late Eocene locality of Ban Mark in the Krabi basin, Thailand. The new material described, comprising upper and lower cheek teeth, deciduous premolars and partial cranial remains, makes E. jaegeri the best‐documented Eocene representative of Old World Suoidea at present. Detailed study and comparison of their cheek teeth structure reveal a homogeneity of the molar crest and groove patterns of Old World and New World Palaeogene suoids.     

The complex nature of progenetic species — examples from Mesozoic ammonites

Several examples of progenetic species among Mesozoic ammonites are investigated. The ammonites are Middle Jurassic kosmoceratids, Upper Jurassic oppeliids, and Upper Cretaceous scaphites. As assessed through outgroup comparison, the progenetic species in each of these examples is characterized by small size at maturity and the presence of morphological features typical of those of the juveniles of more primitive species. However, in none of these examples is the progenetic species a duplicate form of the juvenile stage of more primitive species. There are at least three kinds of features of progenetic species that differ from those of the juveniles of more primitive species: (1) symplesiomorphous features associated with maturation, (2) unique features whose presence is not clearly related to progenetic processes, and (3) unique features that may represent epigenetic outgrowths of juvenile morphology. This novel combination of juvenile. adult. and unique features may endow progenetic species with the evolutionary potential to play a role in the origin of higher taxa. □ Progenesis, heterochrony, Ammon-oidea. Jurassic, Cretaceous.     

Within‐plant distribution of 1,4‐benzoxazin‐3‐ones contributes to herbivore niche differentiation in maize

Plant defences vary in space and time, which may translate into specific herbivore‐foraging patterns and feeding niche differentiation. To date, little is known about the effect of secondary metabolite patterning on within‐plant herbivore foraging. We investigated how variation in the major maize secondary metabolites, 1,4‐benzoxazin‐3‐one derivatives (BXDs), affects the foraging behaviour of two leaf‐chewing herbivores. BXD levels varied substantially within plants. Older leaves had higher levels of constitutive BXDs while younger leaves were consistently more inducible. These differences were observed independently of plant age, even though the concentrations of most BXDs declined markedly in older plants. Larvae of the well‐adapted maize pest Spodoptera frugiperda preferred and grew better on young inducible leaves irrespective of plant age, while larvae of the generalist Spodoptera littoralis preferred and tended to grow better on old leaves. In BXD‐free mutants, the differences in herbivore weight gain between old and young leaves were absent for both species, and leaf preferences of S. frugiperda were attenuated. In contrast, S. littoralis foraging patterns were not affected. In summary, our study shows that plant secondary metabolites differentially affect performance and foraging of adapted and non‐adapted herbivores and thereby likely contribute to feeding niche differentiation.     

Morphometric analysis and taxonomic revision of Anisopteromalus Ruschka (Hymenoptera: Chalcidoidea: Pteromalidae) – an integrative approach

We use an integrative taxonomic approach to revise the genus Anisopteromalus. In particular, we apply multivariate ratio analysis (MRA), a rather new statistical method based on principal component analysis (PCA) and linear discriminant analysis (LDA), to numerous body measurements and combine the data with those from our molecular analysis of Cytb and ITS2 genetic markers (on a subset of species) and all available published data on morphology, karyology, behaviour, host associations and geographic distribution. We demonstrate that the analysis of quantitative characters using MRA plays a major role for the integration of name‐bearing types and thus for the association of taxa with names. Six species are recognized, of which two are new: A. cornis Baur sp.n. and A. quinarius Gokhman & Baur sp.n. For Anisopteromalus calandrae (Howard), a well‐known, cosmopolitan parasitoid of stored‐product pests, we have selected a neotype to foster continuity and stability in the application of this important name. The species was sometimes confused with the related A. quinarius sp.n. , another cosmopolitan species that is frequently encountered in similar environments. We also show that several species originally described or later put under Anisopteromalus actually belong to different genera: Cyrtoptyx camerunus (Risbec) comb.n. ; Meraporus glaber (Szelényi) comb.n. ; Dinarmus schwenkei (Roomi, Khan & Khan) comb.n. Neocatolaccus indicus Ayyar & Mani is confirmed as a junior synonym of Oxysychus sphenopterae (Ferrière) syn.n. and Anisopteromalus calandrae brasiliensis (Domenichini) stat.rev. must be considered as a valid but doubtful taxon. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:BDFE96D3‐D0F4‐4012‐90F5‐9A087F7F5864 .     

Species‐specific microsatellite markers to monitor gene flow between exotic poplars and their natural relatives in eastern North America

Species‐specific microsatellite markers were obtained for the unambiguous recognition of five poplar species of ecological and commercial importance to eastern North America: the native species Populus balsamifera and Populus deltoides, the exotic species Populus maximowiczii, Populus nigra, Populus trichocarpa and their interspecific hybrids. Forty‐four of 71 tested primer pairs amplified simple sequence repeat (SSR) loci for all five taxa. Six of these loci showed non‐overlapping allelic diversity between species, including fixed differences. Together, they were useful to identify unambiguously the five taxa and to validate parental contributions in a group of hybrid progeny. These markers will be invaluable to detect gene flow from plantations of exotic poplar into adjacent stands of native species and between the two potentially hybridizing native species P. balsamifera and P. deltoides.     

Do photosynthetic limitations of evergreen Quercus ilex leaves change with long‐term increased drought severity?

Seasonal drought can severely impact leaf photosynthetic capacity. This is particularly important for Mediterranean forests, where precipitation is expected to decrease as a consequence of climate change. Impacts of increased drought on the photosynthetic capacity of the evergreen Quercus ilex were studied for two years in a mature forest submitted to long‐term throughfall exclusion. Gas exchange and chlorophyll fluorescence were measured on two successive leaf cohorts in a control and a dry plot. Exclusion significantly reduced leaf water potential in the dry treatment. In both treatments, light‐saturated net assimilation rate (A_max), stomatal conductance (g_s), maximum carboxylation rate (V_cmax), maximum rate of electron transport (J_max), mesophyll conductance to CO₂ (g_m) and nitrogen investment in photosynthesis decreased markedly with soil water limitation during summer. The relationships between leaf photosynthetic parameters and leaf water potential remained identical in the two treatments. Leaf and canopy acclimation to progressive, long‐term drought occurred through changes in leaf area index, leaf mass per area and leaf chemical composition, but not through modifications of physiological parameters.     

Shoot development and bud mite infestation in hazelnut (Corylus avellana)*

The interaction of environmental and genetic variation in hazelnut (Corylus avellana) shoot development and the behaviour, survival, and colonisation of eriophyid bud mites (Phytoptus avellanae and Cecidophyopsis vermiformis) were studied. The distribution of galled buds on shoots indicated that mites colonised only those buds formed during the mite migration period. The point of entry is probably the growing shoot tip. Once within this structure, as the shoot develops the mites have access to a succession of newly-formed, bud primordia that are unprotected by bud scales. The relative accessibility of the apical meristem and bud primordia may affect host susceptibility.     

Effects of synthetic plant growth retardants and abscisic acid on root functions of Brassica rapa plants exposed to low root-zone temperature

Possible interactions of two synthetic plant-growth retardants during the short-term response of Brassica rapa L. ssp. oleifera (DC.) Metzger plants to low root-zone temperature were investigated by pretreating with mefluidide or paclobutrazol. Water and solute transfers were studied by measuring xylem sap volume flow (under root pressure exudation) and ion flow from the roots. Relations with nitrate uptake rate were also considered. Root pretreatment with paclobutrazol strongly restricted the cold-inducible processes which normally restore water and solute flow from the root xylem. Paclobutrazol decreased the rates of nitrate uptake and exudation flow from the root xylem (principally by reducing root hydraulic conductivity) with dramatic consequences for ion flow, especially that of nitrate.
The effects of root ABA pretreatment on plant response to root cooling were then studied separately or in association with a pretreatment with paclobutrazol. Despite a slight decrease in nitrate uptake rate, ABA pretreatment of the roots enabled the plant to develop rapid mechanisms for adaptation to cold constraint at the root level. Moreover, this action of exogenous ABA greatly reduced the effect of a simultaneous paclobutrazol pretreatment and partly restored water and solute flows.
Thus, the improvement of plant resistance to cold conditions brought about by treatments with mefluidide and paclobutrazol (previously shown in long-term experiments) cannot simply be explained by their short-term effects.     

Taxonomic revision of the Mediterranean Plakina Schulze (Porifera, Demospongiae, Homoscleromorpha)

Only three species of the sponge genus Plakina Schulze have been described from the Mediterranean since 1880, in spite of a large amount of allegedly intraspecific variability in morphological characters. However, recent genetic studies based on electrophoretic techniques have revealed extensive cryptic speciation in north-western Mediterranean Plakina , demonstrating that most of this variation was interspecific rather than intraspecific. We describe in detail the morphology and anatomy of four new species of Plakina from the Mediterranean– P. crypta, P. weinbergi, P. endoumensis and P. jani –of which the latter two were discovered through allozyme electrophoresis. Plakina monolopha Schulze and P. trilopha Schulze are redescribed, and their morphological and geographical limits are discussed along with those of P. dilopha Schulze. Accurate analysis of the internal anatomy and of the shape and ramification pattern of lophose spicules in scanning electron microscopy provides new, powerful morphological criteria for species discrimination in Plakina. More widespread use of such new taxonomic characters should provide evidence against the alleged cosmopolitanism of some Plakina species, thus generating an increase in estimates of the biodiversity of plakinids.