The glandular hairs of Valeriana officinalis subsp. collina. I. Some unusual features in their development and differentiation

The ontogeny, morphology, histochemistry and nuclear structure of glandular hairs in Valeriana officinalis L. subsp. collina (Wallr.) Nyman were investigated. An interesting characteristic of these glandular hairs is their remarkable variability, not only in morphology, but in their chromatin activity, and the reactions of the secretions to histochemical tests.     

Investigating South American biogeographic history using patterns of skull shape variation on Cerdocyon thous (Mammalia: Canidae)

Patterns of geographic variation of the canid Cerdocyon thous have historically been obscured by its remarkable intraspecific morphological variability. The observed distribution is highly associated with phytophysiognomy, a feature considered highly dynamic along geological time. In the present study, we tested whether vegetation distribution during the Holocene Glacial Maximum of South America (HGM) explains the patterns of morphological variation within Cerdocyon thous . The species was divided in groups according to paleohabitats that could support their presence during the HGM, and then tested for differences in skull morphometrics. The results obtained demonstrate that the climatic changes during the HGM influenced the population structure of this species, resulting in the establishment of geographical groups with different degrees of morphological cohesion. Higher morphological cohesion found in the Northern group might be explained by the marked discontinuity between its geographical range and the rest of the species'distribution. The Eastern and Southern morphological divergence is less striking and, although this could be related to past vegetation distribution, the disappearance of those barriers leads to a population structure that could be slowly breaking down.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 77–84.     

Diversity patterns of stygobiotic crustaceans across multiple spatial scales in Europe

1. Using species distribution data from 111 aquifers distributed in nine European regions, we examined the pairwise relationships between local species richness (LSR), dissimilarity in species composition among localities, and regional species richness (RSR). In addition, we quantified the relative contribution of three nested spatial units – aquifers, catchments and regions – to the overall richness of groundwater crustaceans.
2. The average number of species in karst and porous aquifers (LSR) varied significantly among regions and was dependent upon the richness of the regional species pool (RSR). LSR–RSR relationships differed between habitats: species richness in karstic local communities increased linearly with richness of the surrounding region, whereas that of porous local communities levelled off beyond a certain value of RSR.
3. Dissimilarity in species composition among aquifers of a region increased significantly with increasing regional richness because of stronger habitat specialisation and a decrease in the geographic range of species among karst aquifers. Species turnover among karst aquifers was positively related to RSR, whereas this relationship was not significant for porous aquifers.
4. The contribution of a given spatial unit to total richness increased as size of the spatial unit increased, although 72% of the overall richness was attributed to among-region diversity. Differences in community composition between similar habitats in different regions were typically more pronounced than between nearby communities from different habitats.
5. We conclude by calling for biodiversity assessment methods and conservation strategies that explicitly integrate the importance of turnover in community composition and habitat dissimilarity at multiple spatial scales.     

Molecular and morphological differentiation between steganacarid mites (Acari: Oribatida) from the Canary islands

Two steganacarid species, Steganacarus ( Steganacarus ) tenerifensis and S . ( S .) carlosi , the first endemic to Tenerife and the second to La Gomera and Tenerife, were found to have such wide morphological variability as to cast doubt on their specific limits. Cluster analysis and MDS ordering were used to quantify morphological variation, and biochemical procedures were used to assess genetic variation in the two entities. The results revealed disagreement between the morphological and genetic data as reported in previous studies on steganacarid mites. Morphological traits were highly heterogeneous in the Canary island populations and genetic structure was homogeneous with very low heterozygosity. The separation of the two Canary island species, not to mention the phenotypes close to carlosi , is difficult to justify due to their very high genetic identity. The presence of morphological intermediates suggests the same conclusion. However, the sympatry of some phenotypes and previous data on this animal group are a source of doubt and suggest that further investigations are needed before conclusions can be reached in this regard. Correlations between morphological differentiation and known palaeogeographic events are suggested in the light of the possible evolutionary history of the steganacarid mites on the Canary islands.     

Chirocentrids as engrauloids: evidence from suspensorium,branchial arches,and infraorbital bones (Clupeomorpha,Teleostei)

The Chirocentridae is a family of highly specialized large predatory clupeomorphs composed of two species from coastal waters of the Indian and western Pacific Oceans. Peculiarities of the anatomy of these fishes have puzzled ichthyologists who attempted to resolve their phylogenetic relationships. Despite controversy, it is currently accepted that the Chirocentridae is a family of Clupeiformes, included with the Clupeidae in the superfamily Clupeoidea. New data support an alternative hypothesis. Seven previously unreported derived character states from the suspensorium, branchial arches, and infraorbitals strongly indicate a hitherto unsuspected sister group relationship between the Chirocentridae and Engrauloidea, which comprises approximately 140 species of the commercially important fishes known as anchovies. These are character states: (1) the anterior margin of metapterygoid located anterior to the quadrate; (2) the ventral limb of hyomandibula and quadrate not separated by the metapterygoid; (3) the posterodorsal margin of metapterygoid in line with the condyle of articulation of the hyomandibula with the opercle; (4) the presence of a laminar outgrowth of the anterior margin of the quadrate; (5) the endochondral portion of the quadrate in the shape of an isosceles triangle; (6) the presence and arrangement of autogenous tooth plates on ceratobranchials 1 to 3; and (7) posterior region of infraorbital 1 well developed and extending along the ventral margin of infraorbital 2. Three of those character states are further modified and hypothesized as synapomorphies of the Engrauloidea: (1′) a substantial portion of the metapterygoid situated anterodorsal to the quadrate, (2′) articulation between the ventral limb of the hyomandibula and the quadrate, and (7′) infraorbitals 1 and 3 articulating by means of a well‐developed laminar process of the posterior region of infraorbital 1. The separation of the dorsal, paired elements of the branchial arches of the Chirocentridae and representative Engrauloidea is apomorphic within the Clupeoidei, and constitutes circumstantial evidence for the sister group relationship between those clades. Microphagy within the Engrauloidea is secondary, homoplastic to the same condition present in other clades of the Clupeiformes. The decomposition of character complexes into discrete morphological characters and its use in phylogenetic inference is discussed. The sister group relationship between the Chirocentridae and Engrauloidea renders the Clupeoidea paraphyletic. A new classification of the Clupeoidei, with the inclusion of the Chirocentridae in the Engrauloidea, is proposed. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 363–383.     

Pre‐wintering conditions and post‐winter performance in a solitary bee: does diapause impose an energetic cost on reproductive success?

1. Diapause is a dynamic process of low metabolic activity that allows insects to survive periods of harsh conditions. Notwithstanding the lowered metabolism, and because diapausing insects have no access to food, diapause has an energetic cost that may affect post‐diapause performance. 2. Previous studies on the solitary bee Osmia lignaria have shown that prolonged pre‐wintering periods (the time during which individuals already in diapause remain at warm temperatures) are associated with elevated lipid consumption, fat body depletion, and body weight loss. The present study investigated whether prolonged pre‐wintering also affects reproduction, i.e. whether the costs associated with diapause could have an effect on post‐diapause performance in this species. 3. Females were exposed to a range of pre‐wintering conditions, and ovary development and individual post‐wintering performance were monitored throughout their adult life span. 4. No evidence of an effect of pre‐wintering duration on post‐diapause reproductive success was found. Expected differences in the timing of establishment were not observed because ovary maturation was, surprisingly, not arrested during pre‐wintering. Prolonged pre‐wintering duration did not result in decreased life span, probably because emerging females could rapidly replenish their metabolic reserves through feeding. However, there was a very strong effect of the duration of the pre‐emergence period on the likelihood of nest establishment. 5. Longevity, the main factor determining fecundity in Osmia, is subjected to high levels of intrinsic variability, even among females of similar size exposed to identical conditions during development and nesting.     

Species of the family Cepheidae Berlese, 1896 (Acarida: Oribatida) from the Maghreb

The species of cepheid mites (Acarida, Oribatida, Cepheidae) from Maghrebian soils are listed and taxonomically revised. The six species, including two new entities, one of which represents the new genus Tereticepheus , offer interesting data for a biogeographical discussion of faunal movements in the western Mediterranean area during the last 20 million years.