Table of Contents

16 March 2016, Volume 54 Issue 2
Cover illustration: Maps in the left panel show predicted species distributions of Cornus florida L. at present, during the Last Glacial Maximum, and the future, respectively (for details see Fig. 9 in Call et al., this issue). Map in the middle shows the eco-regions of eastern United States and the sampling locations of C. florida (Fig. 1). Map in the bottom middle shows the spatial distribution of haplotype diversity of C. florida (Fig. 2). Line graph at the middle right shows the chloropl [Detail] ...
    Research Articles
  • Harald Schneider
    J Syst Evol. 2016, 54(2): 93-103.
    Utilization of ferns by phytophagous insects is widely considered to be less common and less specialized compared to the phytophagous insect community feeding on angiosperms. In this study, this assumption is challenged by exploring the evolution of pteridophagy (fern-feeding) in the larval stages of sawflies (Symphyta). To achieve this, phylogenetic frameworks were assembled based on published phylogenetic studies and newly reconstructed phylogenies based on cytochrome oxidase subunit I (COI) barcoding data that allowed the reconstruction of the ancestral feeding preferences by plotting reported host plants of sawflies. Evidence was found for two exclusively pteridophagous lineages of sawflies that probably originated before the Cretaceous Terrestrial Revolution, whereas the third lineage comprising several exclusively pteridophagous sawfly genera is nested in the derived sawfly clade feeding predominantly on eudicots. Thus, the evolution of pteridophagy in the clade was probably connected with the transformation of terrestrial habitats associated with the rise of angiosperms during the Cretaceous. The observed phylogenetic patterns are consistent with the hypothesis of “larval diet conservatism” resulting in the establishment of genera and lineages that feed exclusively, or at least predominantly, on conifers, eudicots, ferns, and monocots. Only a small percentage of sawfly genera were found to be polyphylophagous. The results suggest a low frequency of switches between host plants belonging to different major plant lineages such as angiosperms, conifers, and ferns. Successful switches between hosts belonging to different major lineages of land plants coincide with the reorganization of the phylogenetic composition of terrestrial vegetation in the late Mesozoic.
  • Hannah Graves, A. Lane Rayburn, Sumin Kim, D. K. Lee
    J Syst Evol. 2016, 54(2): 104-112.
    Chloroplast DNA (cpDNA) is most often maternally inherited and highly conserved leading to previous observation of little to no sequence variation. Comparing cpDNA haplotypes have provided valuable insight into the establishment and migration of polyploid populations. However, to use chloroplast haplotypes to their full potential intrapopulational variation needs to be addressed. In this study, cpDNA haplotype variation was surveyed within 16 natural populations of prairie cordgrass (Spartina pectinata Link) located east of the 100th west meridian and north of the 35th north parallel in the U.S.A. using two non-coding, polymorphic chloroplast regions. Two main clades were defined with subclades as follows: haplotype 1 and haplotype 2A and 2B. It was discovered that seven populations showed intrapopulational chloroplast genome variation. Of the total amount of variation, 95.5% occurred within the octoploid populations and 4.5% occurred within the tetraploid populations. Both variant haplotypes, 2A and 2B, were found in a larger sampling of one of the natural populations, but no variation was found in a mixed ploidy population. The intrapopulational cpDNA variation we found in this study cannot directly be related to mechanisms of introduction of the non-native populations into native populations. Therefore, this cpDNA variation could be novel natural variation that has been fixed as the octoploid populations were established and moved northwest. This analysis provides insight into determining the usefulness of indels and single nucleotide polymorphisms for population identification and may provide information in regards to the origin of chloroplast variation and its subsequent fixation and establishment in natural prairie cordgrass populations.
  • Jia-Mei Li, Wei-Juan Sun, Ying Chang, Wen-Guang Yang
    J Syst Evol. 2016, 54(2): 113-122.
    A phylogenetic analysis was carried out to clarify the systematic position of Gyrocheilos and Didymocarpus, particularly the species placed in Didymocarpus sect.Heteroboea by Wang et al. Based on sequencing the internal transcribed spacer and the chloroplast spacer trnL-F, parsimony and Bayesian inference analyses were carried out using separate nuclear and chloroplast datasets, as well as a combined dataset. Our results showed that the two sections of Didymocarpus in China andGyrocheilos did not form separate monophyletic subclades, but turned up in three different places in the phylogenetic trees. In the frame of the present study, the pollen morphology of the species included in the analysis was studied. It proved inconsistent with the delimitation between Didymocarpus and Gyrocheilos. Furthermore, pollen and other morphological characters indicate that Gyrocheilos and some taxa of Didymocarpus should be placed within Didymocarpus.
  • Cristina Salmeri, Cristian Brullo, Salvatore Brullo, Giampietro Giusso Del Galdo, Ivan I. Moysiyenko
    J Syst Evol. 2016, 54(2): 123-135.
    Allium paniculatum L. is commonly recorded from the Euro-Mediterranean and Irano-Turanian regions. Evidence from literature and herbarium collections revealed that many different taxa of A. sect. Codonoprasum Rchb., all characterized by big size, diffuse and densely flowered umbrella, very long spathe valves, long pedicels, and cylindrical-campanulate perigon, have been wrongly attributed to this species thus affecting records on its geographic distribution and morphological characterization. In order to define the true identity of A. paniculatum, we analyzed specimens coming from the type locality (Don River), and provided details on morphology, ecology, karyology, leaf anatomy, seed morphology and seed coat micro-sculpturing. Taxonomic and phylogenetic relationships with related species of sect. Codonoprasum and with other taxa of different sections were investigated by means of morphological characters and molecular data from the internal transcribed spacers (ITS) nrDNA and the trnH-psbA cpDNA region. Maximum parsimony and Bayesian inference analyses of molecular data recovered two main clades in A. sect. Codonoprasum and clearly separated A. paniculatum from related taxa. The taxonomic implications of these patterns of relationships are discussed. To our knowledge, this is the first study documenting in-depth phylogenetic relationships within A. sect. Codonoprasum.
  • Ashley Call, Yan-Xia Sun, Yan Yu, Peter B. Pearman, David T. Thomas, Robert N. Trigiano, Ignazio Carbone, Qiu-Yun (Jenny) Xiang
    J Syst Evol. 2016, 54(2): 136-151.
    Repeated global climatic cooling and warming cycles during the Pleistocene played a major role in the distribution and evolution of the Earth biota. Here, we integrate phylogeography, coalescent-based Bayesian estimation of demographic history, and species distribution modeling (SDM) to understand the genetic patterns and biogeography of the flowering dogwood, Cornus florida subsp. florida L., since the Last Glacial Maximum (LGM). Natural populations of the species are severely threatened by dogwood anthracnose. We genotyped 306 plants from 73 locations of the species across most of its native distribution with three DNA regions from the plastid genome, ndhF-rpl32, rps16 and trnQ-rps16. The genealogy and haplotype network reconstruction revealed two haplotype lineages diverging ≈3.70 million years ago. We detected no clear geographic structuring of genetic variation, although significant local structure appeared to be evident, likely due to a combination of substantial localized seed dispersal by small mammals and small population size/limited sampling at a location. The spatial distribution of haplotype frequencies, estimated population demographic history, and results from hindcasting analysis using SDM suggested refugia in southeastern North America and population reduction during the LGM, followed by rapid post-glacial expansion to the north. Forecasting analysis using SDM predicted range shifts to the north under ongoing global warming. Our results further suggested that gene flow via seed dispersal has been high but insufficient to counter the effect of genetic drift. This study demonstrates the benefit of integrating genetic data and species distribution modeling to obtain corroborative evidence in elucidating recent biogeographic history and understanding of genetic patterns and species evolution.
  • Pan-Pan Wu, Hong-Wei Zuo, Genlou Sun, De-Xiang Wu, Bjorn Salomon, Qun-Wen Hu, Zhao-Rong Dong
    J Syst Evol. 2016, 54(2): 152-161.
    One of the challenges in evolutionary biology is to understand the evolution of speciation with incomplete reproductive isolation as many taxa have continued gene flow both during and after speciation. Comparison of population structure between sympatric and allopatric populations can reveal specific introgression and determine if introgression occurs in a unidirectional or bidirectional manner. Simple sequence repeat markers were used to characterize sympatric and allopatric population structure of plant species, Elymus alaskanus (Scribn. and Merr.) Löve, E. caninus L., E. fibrosus (Schrenk) Tzvel., and E. mutabilis (Drobov) Tzvelev. Our results showed that genetic diversity (HE) at species level is E. caninus (0.5355) > E. alaskanus (0.4511) > E. fibrosus (0.3924) > E. mutabilis (0.3764), suggesting that E. caninus and E. alaskanus are more variable than E. fibrosus and E. mutabilis. Gene flow between species that occurs within the same geographic locations versus gene flow between populations within species was compared to provide evidence of introgression. Our results indicated that gene flow between species that occur within the same geographic location is higher than that between populations within species, suggesting that gene flow resulting from introgressive hybridization might have occurred among the sympatric populations of these species, and may play an important role in partitioning of genetic diversity among and within populations. The migration rate from E. fibrosus to E. mutabilis is highest (0.2631) among the four species studied. Asymmetrical rates of gene flow among four species were also observed. The findings highlight the complex evolution of these four Elymus species.
  • Kumar Vinod Chhotupuri Gosavi, Shrirang R. Yadav, K. Praveen Karanth, Siddharthan Surveswaran
    J Syst Evol. 2016, 54(2): 162-174.
    The genus Glyphochloa (Poaceae: Panicoideae: Andropogoneae: Rottboellinae) is endemic to peninsular India and is distributed on lateritic plateaus of low and high altitude in and around Western Ghats and the Malabar Coast. The genus presumably originated and diversified in the Western Ghats. Species relationships in the genus Glyphochloa were deduced here based on molecular phylogenies inferred using nuclear ribosomal ITS sequences and plastid intergenic spacer regions (atpB-rbcL, trnT-trnL, trnL-trnF), and new observations were made of spikelet morphology, caryopsis morphology and meiotic chromosome counts. We observed two distinct clades of Glyphochloa s.l. One of these (‘group I’) includes Ophiuros bombaiensis, and is characterized by a single-awned lower glume and a base chromosome number of 6; it grows in low elevation coastal areas. The other clade (‘group II’) has a double-awned lower glume, a base chromosome number of 7, and is restricted to higher elevation lateritic plateaus; G. ratnagirica may belong to the group II clade, or may be a third distinct lineage in the genus. A sister-group relationship between group I and II taxa (with or without G. ratnagirica) is not well supported, although the genus is recovered as monophyletic in shortest trees inferred using ITS or concatenated plastid data. We present a key to species of Glyphochloa and make a new combination for O. bombaiensis.
  • Paulo C. Baleeiro, Richard W. Jobson, Paulo T. Sano
    J Syst Evol. 2016, 54(2): 175-186.
    Utricularia sect. Foliosa Kamiénski comprises three recognized species, U. amethystina Salzm. ex A.St.-Hil. & Girard, U. tricolor A.St.-Hil., and U. tridentata Sylvén, delimited based mainly on shape and structure of the corolla. In comparison with the two latter members of the section, U. amethystina forms a complex of morphological variants, reflected taxonomically by the previous recognition of 31 synonyms. In his monograph of the genus, Taylor synonymized these taxa based primarily on his observation of continuous morphological variation of the flowers. In the same treatment he also suggested a future taxonomic re-evaluation could re-establish two, three or more taxa. Here we examine this question utilizing morphometric analyses of floral variation across most of the synonyms mentioned above, within populations from across their Neotropical distribution. Based on both morphological and geographic characters we identify strongly differentiated morphotypes. Our data provide support for both the maintenance of taxa previously recognised as synonyms under U. amethystina, and the resurrection of taxa to species status, namely U. bicolor, U. damazioi, U. lindmanii and U. hirtella, and four other putative new taxa.
  • J Syst Evol. 2016, 54(2): 187-187.