Phylogenetic analysis of the Mexican freshwater crabs of the tribe Pseudothelphusini (Decapoda: Brachyura: Pseudothelphusidae)

The Mexican pseudothelphusid crabs are classified in one subfamily, three tribes, and 13 genera. Up to now, 56 species have been recognized, distributed in a strictly Neotropical pattern, with some of them reaching the state of Sonora on the western slope of Mexico. The tribe Pseudothelphusini is the most diverse, with five genera and 35 species, all of them endemic to Mexico: the two most species‐rich genera are Pseudothelphusa, with 23 species, and Tehuana, with eight species; Epithelphusa includes two species, whereas Disparithelphusa and Smalleyus are monotypic. The Pseudothelphusini lack an updated systematic revision, which could serve as a framework to analyse the monophyletic origin of the group, to clarify the relationships among genera and species, as well as to resolve the taxonomic status of various species complexes. In the present study, an exhaustive morphological revision was conducted using somatic and sexual characters. A phylogenetic analysis was performed using 77 characters and 183 character states, taken from 41 species. Ten trees of the same length were obtained using PAUP 4.0 through a heuristic search. The results show that the tribe as it is actually known constitutes a paraphyletic group, in which the species of Epithelphusa and Pseudothelphusa puntarenas are excluded from the internal group. According to the obtained results, the tribe Pseudothelphusini s.s. includes five genera: Smalleyus, Pseudothelphusa, Tehuana, and two new ones to accommodate Pseudothelphusa galloi and Pseudothelphusa sulcifrons, respectively. This new arrangement considers the provisional suppression of the genus Disparithelphusa, which remained as another species of Pseudothelphusa throughout the cladistic analysis. The phylogenetic results show a strong congruence with the distribution of the species, in several cases grouping species that form morphological clines along a geographical gradient. The previously proposed southern origin of the tribe Pseudothelphusini gains support with the results obtained. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 457–481     

Citrus abscission and Arabidopsis plant decline in response to 5-chloro-3-methyl-4-nitro-1H-pyrazole are mediated by lipid signalling

The compound 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP) is a pyrazole-derivative that induces abscission selectively in mature citrus (Citrus sinensis) fruit when applied to the canopy and has herbicidal activity on plants when applied to roots. Despite the favourable efficacy of this compound, the mode of action remains unknown. To gain information about the mode of action of CMNP, the effect of application to mature citrus fruit and Arabidopsis thaliana roots was explored. Peel contact was essential for mature fruit abscission in citrus, whereas root drenching was essential for symptom development and plant decline in Arabidopsis. CMNP was identified as an uncoupler in isolated soybean (Glycine max) mitochondria and pea (Pisum sativum) chloroplasts and an inhibitor of alcohol dehydrogenase in citrus peel, but not an inhibitor of protoporphyrinogen IX oxidase. CMNP treatment reduced ATP content in citrus peel and Arabidopsis leaves. Phospholipase A₂ (PLA₂) and lipoxygenase (LOX) activities, and lipid hydroperoxide (LPO) levels increased in flavedo of citrus fruit peel and leaves of Arabidopsis plants treated with CMNP. An inhibitor of PLA₂ activity, aristolochic acid (AT), reduced CMNP-induced increases in PLA₂ and LOX activities and LPO levels in citrus flavedo and Arabidopsis leaves and greatly reduced abscission in citrus and delayed symptoms of plant decline in Arabidopsis. However, AT treatment failed to halt the reduction in ATP content. Reduction in ATP content preceded the increase in PLA₂ and LOX activities, LPO content and the biological response. The results indicate a link between lipid signalling, abscission in citrus and herbicidal damage in Arabidopsis.     

Skull morphology and functionality of extant Felidae (Mammalia: Carnivora): a phylogenetic and evolutionary perspective

Felids morphology and ecological role as hypercarnivores are quite constant, despite considerable body size variation among species. Skull morphological and functional features of 34 extant cat species were evaluated under a phylogenetic framework of the Felidae. Twenty skull measurements were analysed through Principal Component Analysis to assess the species morphofunctional spaces. Force indexes were obtained from static equilibrium equations to infer jaw mechanics. Correlations between morphological, functional, and ecological traits were tested by phylogenetically independent contrasts. In spite of the general cat‐like pattern, specific features on the skulls allowed differentiation among groups. Acinonyx jubatus, for instance, showed a shorter and shallower temporal fossa than other big cats, and their bite functionality is marked by an increased contribution of the masseteric system. A morphofunctional dichotomy between Neotropical and Eurasian/African small cats was detected, and is associated with the major transversal axes of the skulls. According to the contrast analyses, the skull size is correlated with the bite force and prey size, but it is uncorrelated with the variations on jaw mechanics (from temporalis or masseter muscle optimizations). Also, there was no correlation between functional differences on jaw muscles and the ratio of prey weight to cat weight. The efficiency of the jaw apparatus among cats is quite consistent; therefore, the different evolutionary trends of jaw mechanics seem to be caused by the casuistic fixation of phenotypical variations, rather than by specific adaptative selections. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 414–462.     

Enhanced Multiplication of Intracellular (Amastigote) Stages of Trypanosoma cruzi In Vitro1

Amastigotes of different strains of Trypanosoma cruzi responded to stimulation with concanavalin A in an axenic medium by increased DNA synthesis and cell multiplication. These effects were inhibited by α-methyl mannoside. Other mitogens, i.e. phytohemagglutinin P, castor bean ricin Type II isolated from Ricinus communis, and a bacterial lipopolysaccharide, had no effect on amastigote growth. Amastigote stimulation by concanavlin A lends itself to studies on the biochemistry and cell cycle of this human pathogen.     

Cryptic diversity within the Moroccan endemic day geckos Quedenfeldtia (Squamata: Gekkonidae): a multidisciplinary approach using genetic,morphological and ecological data

Quedenfeldtia (Boettger, 1883) is a genus of diurnal geckos, endemic to the Atlas Mountains in Morocco, with two species being recognized: Quedenfeldtia moerens and Quedenfeldtia trachyblepharus. Quedenfeldtia moerens is found across a wide variety of habitats, from sea level to 3000 m a.s.l., whereas Q. trachyblepharus occupies exclusively high mountain regions reaching up to 4000 m a.s.l. This differentiation, offers an interesting model for study biogeographical patterns and evolutionary scenarios in a North African endemic. Analysis of two mitochondrial (12S rRNA and ND4) and four nuclear (ACM4, MC1R, PDC, and Rag1) DNA markers revealed high genetic variation, consistent with other recent phylogeographical studies, and with the two currently described species. However, within each species, a subdivision into two groups with geographical consistence was found. Multivariate morphological analyses confirmed the existence of two main phenotypes, whereas ecological niche modelling identified various environmental variables associated with the distribution of each species, and helped to predict occurrences outside the confirmed ranges. The results obtained in the present study indicate the possible existence of additional ‘cryptic’ species within this genus, a condition found in many North African reptiles, and particularly common in geckos. In general, North African montane fauna appears to reflect the occurrence of diverse palaeoendemics, as seen in Central Africa Mountain systems, rather than the pattern of recent postglacial recolonization observed in Europe. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

From forest to plantation? Obscure articles reveal alternative host plants for the coffee berry borer,Hypothenemus hampei (Coleoptera: Curculionidae)

The coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae), is the most devastating insect pest of coffee throughout the world. The insect is endemic to Africa but can now be found throughout nearly all coffee‐producing countries. One area of basic biology of the insect that remains unresolved is that of its alternative host plants, i.e. which fruits of plants, other than coffee, can the insect survive and reproduce in. An in‐depth survey of the literature revealed an article by Schedl listing 21 genera in 13 families in which the insect was collected, mainly in the Democratic Republic of Congo. This overlooked reference, together with information provided in other early articles, suggests that H. hampei is polyphagous, and could provide, if confirmed in the field, critical information on the evolution of this insect's diet, ecology and host range. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.     

Gut-associated yeast in bark beetles of the genus Dendroctonus Erichson (Coleoptera: Curculionidae: Scolytinae)

Scolytine bark beetles are the most destructive pests of conifers; they sometimes aggregate in such large numbers that they actually kill their hosts. They maintain close relationships with yeasts and fungi, in particular those that are assumed to aid in digestive, detoxification processes and pheromone production. In this study, 403 yeast strains were isolated from the guts, ovaries, eggs and frass of nine bark beetle species in the genus Dendroctonus Erichson. The beetles were collected from 10 conifer species at 34 locations in Mexico, Guatemala and the USA. Yeast identification was based on partial DNA sequences from 18S rDNA, 26S rDNA and internal transcribed spacer (ITS1), as well as morphological and physiological characteristics. A combined phylogenetic analysis delimited 11 clades with sequences similar to Candida arabinofermentans , C. ernobii , C. membranifaciens (including C. lessepsii , Pichia mexicana and P. scolyti ), C. oregonensis , C. piceae , Kuraishia capsulata (including K. capsulata and K. cf. molischiana ), Pichia americana , P. canadensis , P. glucozyma , P. guilliermondii and an undescribed species of Candida . Nucleotide divergences between the major clades were at least 5% while, with the exception of 30 isolates, yeasts within clades differed from named reference species at fewer than 1% of the nucleotide sites. There do not appear to be obligate relationships between particular yeasts and specific anatomical partitions, nor between particular yeasts and bark beetle species. Some yeasts do appear to be preferentially associated with bark beetles feeding on different conifer genera and therefore host plant defences may limit yeast community diversity in Dendroctonus .  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 325–342.