Morphometric analysis of interspecific and microgeographic variation of crayfish from a Mexican cave

Two undescribed species of Procambarus crayfish (Crustacea, Decapoda) inhabit the subterranean stream running in the recently explored Cueva de Los Camarones, Chiapas, Mexico. Individuals ranging from dark, robust, large-eyed forms with an epigean mien to pale, comparatively slender, microphthalmic ones resembling related troglobites were found, but only the extremes could be distinguished visually. Evolutionary relationships among individuals were investigated morphometrically by means of multivariate analysis'on 14 body dimensions. These analyses revealed a significant discontinuity between the two species, mainly determined by the shape of the rostrum, chelae and telson. The occurrence of a few aberrant phenotypes may indicate the existence of some gene flow between the two species.
Microgeographic variation was demonstrated within the less cavernicolous species. The characters involved were the same as those that discriminate between the two species. These results are compared with allozymic data presented in a parallel paper and the role of genie introgression and environmental induction are discussed.     

Allozymic and morphometric analysis of populations in the Zygaena purpuralis complex (Lepidoptera, Zygaenidae)

In Central Europe and Asia Minor Zygaena purpuralis and Z. minos are two sibling species exhibiting a considerable geographic variation in several features. In this study we examine some populations from the Central and Southern Apennines (Italy) by comparing multivariate analyses of individual allozymic multilocus profiles and of individual morphometric profiles of male genitalia in order to assess their genetic and phenetic relationships.
Results indicate that populations of Z. purpuralis in the Apennines behave in rather different ways with respect to the occurrence of gene exchange with other gene pools. No gene flow appears to occur between two geographically close southern populations; however, extensive introgression, revealable at both the allozymic and morphometric level, seems to occur between some purpuralis and minos -like sympatric populations from Abruzzi. Evolutionary relationships among these peninsular Italy populations are discussed with reference to historical factors, that is, the occurrence of multiple Pleistocene refugia, which could have determined different degrees of isolation among gene pools. This situation is rather different from that previously outlined for Central Europe and present results suggest that the Z. purpuralis complex might include more than two biological species.     

Effect of temperature and dark pretreatment on the germination of three species of Jamesonia (Pteridaceae,Polypodiopsida)

To study the influence of temperature on the germination ability of three species of Jamesonia (Jamesonia imbricata, Jamesonia scammaniae and Jamesonia rotundifolia), spores were cultured at 10°C, 15°C and 20°C. A temperature of 15°C was selected as representative of the natural annual average temperature of the paramo environment that Jamesonia species inhabit. In addition, a dark pretreatment of 2 days was tested to verify if germination was enhanced. The results indicated that germination of Jamesonia, considering the three species as a whole, is affected by temperature, but is independent of the dark treatment. All species showed higher and faster germination at 20°C, and exhibited a threshold minimum temperature around 10°C, below which germination is avoided or extremely low and delayed. This could suggest that spore germination in Jamesonia is adapted to establish gametophyte populations during frost‐free periods.     

Evolutionary geographic relationships among orthocladine chironomid midges from maritime Antarctic and sub‐Antarctic islands

Two species of chironomid midges are currently described in the genus Belgica Jacobs, 1900. Belgica antarctica Jacobs, 1900 is endemic to parts of the maritime Antarctic, and Belgica albipes (Séguy, 1965) is endemic to Îles Crozet, a sub‐Antarctic archipelago in the southern Indian Ocean. The relationships between these species, and their closest known relative (Eretmoptera murphyi Schaeffer, 1914, endemic to sub‐Antarctic South Georgia), were examined by sequencing DNA fragments for domains 1 and 3–5 of 28S ribosomal DNA and the mitochondrial gene cytochrome c oxidase 1 (cox1). The resulting molecular relationships between the three species were unclear, although their position within the subfamily Orthocladiinae of the Chironomidae, as generated by classical taxonomy, was confirmed. Our data reinforce earlier doubts, based on classical morphological approaches, that the generic placement of E. murphyi may be incorrect. Further analyses may indeed confirm that the species represents a third member of the genus Belgica. Genetic distance analysis, limited to the barcode region of cox1, indicated high differentiation between the two populations of B. albipes sampled (one obtained from the type location), suggesting the likely presence of cryptic species within this taxon, and that the taxonomic status of this species should be revised. Analysis of cox1 sequences in B. antarctica highlighted a strong genetic structure between populations obtained from 12 locations along the Antarctic Peninsula and the South Shetland Islands archipelago, with a number of distinctive mtDNA lineages inhabiting geographically distinct areas. In particular, we found four different haplogroups constituting geographically close but genetically distinct populations, a pattern likely to have been encouraged by the brachyptery of the members of this genus. We suggest that the different genetic patterns shown by each haplogroup have probably been determined by historical dispersal and colonization events during the Pleistocene, and are consistent with their survival in refuges in situ during successive glacial maxima over this period. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 258–274.     

A taxonomic revision of western Eupholidoptera bush crickets (Orthoptera: Tettigoniidae): testing the discrimination power of DNA barcode

The genus Eupholidoptera includes 46 Mediterranean species distributed from Turkey to Greece, Italy and southern France. In the eastern part of its range, Eupholidoptera has been considered to consist of several distinct species, while in the Balkans and Italian peninsula only E. chabrieri has been recognized. However, the status of some Italian populations, confined to particular geographic areas, remains uncertain. To investigate the delimitation of the Italian taxa of Eupholidoptera, we performed both morphological and molecular analyses. Morphological analysis was carried out by considering diagnostic characters usually used to distinguish different taxa, such as the shape of titillators in males and the subgenital plate in females. Molecular analysis was performed by sequencing three mitochondrial genes: 12S rRNA, 16S rRNA, partially sequenced and the entire gene of cox1. Molecular markers were used to infer phylogenetic relationships among the Italian Eupholidoptera species and to reconstruct the historical processes that shaped their current geographic distribution. Results from both morphological and molecular analyses were used to revise the taxonomic arrangement of species. On the whole we were able to distinguish nine lineages of Italian Eupholidoptera, of which E. tyrrhenica sp.n. from Corsica is described as a new species. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:EBD181A0-5263-4880-AC80-66F624506E3A .     

Adaptation and speciation of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae): geographic variation of morphometric indices and allozyme frequencies

Morphometric analyses were carried out for 14 cave dwelling populations of Dolichopoda (Orthoptera, Rhaphidophoridae) from peninsular Italy belonging to the laetitiae-geniculata complex. The selected set of variables includes linear measures of body parts and appendages whose variation is expected to be adaptive and to reflect the degree of specialization to the cave environment.
Inter-population morphometric variation was compared with the patterns of allozyme variation, investigated electrophoretically in a previous paper, by means of ordination and classification multivariate analyses. Results from this comparison reject the hypothesis of parallel geographic variation of morphometric indices and allele frequencies, revealing independent trends for the two sets of characters.