South American Genus Research Articles

An integrative approach to explore species limits in Laelaps mazzai Fonseca, 1939 (Mesostigmata, Laelapidae), a South American widespread mite parasitizing the cricetid Calomys Waterhouse, 1837

Laelaps mazzai Fonseca, 1939 (Mesostigmata, Laelapidae) parasitizes several species of the widespread South American rodent genus Calomys Waterhouse, 1837. Morphological variation has been noticed within this laelapid but has yet to be analyzed. Since several other species of laelapids that initially were considered generalists have resulted in host-specific species, after further analyses, herein we explored, through morphology and genetics, the variation of this parasite across six species of Calomys, trying to establish if it constitutes a polymorphic species or a complex of cryptic host specific-species. An integrative approach was applied, including principal component and discriminant analyses of females and males and DNA sequences (nuclear region ITS and the COI gene). The obtained results indicate that female mites tend to differentiate only the sizes of their dorsal shield among host species but with extensive overlapping. At the same time the males lack metrical differentiation, and the genetic evidence failed to resolve specific-species clades. We conclude that L. mazzai is a single widespread mite with little genetic and phenotypic differentiation.

Revision and analysis of the chromosome variability in the speciose genus Akodon (Rodentia, Sigmodontinae), including new data from Argentina.

Rodentia has a high species number and chromosomal variability. The South American genus Akodon is one of the most speciose muroids, with more than 40 species included in several species groups. Here, we characterize cytogenetically specimens of Akodon from central-western Argentina. Subsequently, we reviewed and analyzed the cytogenetic data for this genus, build a phylogeny and mapped chromosome changes to interpret its evolution. Specimens of A. dolores from central-western Argentina have 2n=42-44/FNa=44 (46, 48) due to a Robertsonian rearrangement. Our data expand the distribution range known for this polymorphism and confirm its geographic structure. Other specimens had 2n=40/FNa=40, representing populations of A. oenos, A. polopi, and A. spegazzinii. All karyotypes have a low amount of heterochromatin, concentrated in centromeres and sex chromosomes, as in other rodents. The complement with 2n=40/FNa=40 is the most frequent in Akodon and is shared by most species in some groups. Chromosome numbers are very diverse. The FNa shows less variability; FNa=42 was recovered as ancestral, excluding A. mimus, which was connected at the base of the Akodon tree and has FNa=44. This indicates a complex chromosome evolution in Akodon, and suggests that reductions and increases in the 2n and FNa evolved independently in some lineages.

Male gametophyte development and cytogenetics of natural diploid and polyploid species of the South American genus Lessingianthus (Asteraceae, Vernonieae)

In view of the scarce cytoembryological knowledge of Lessingianthus and in order to understand the contribution of polyploidy to the evolution of the genus we perform a developmental survey of anthers with the main objective of study if the different ploidy level affect the anther and pollen development in Lessingianthus species and infer the male fertility of diploid and polyploid species. Our results showed that diploid and polyploid species have normal anther development, thus polyploidy did not affect the anther wall development. The following male embryological traits are conserved among the species: tetrasporangiate anthers, four-layered anther wall of dicotyledonous development, with uniseriate persistent epidermis, invasive tapetum, tetrahedral or isobilateral tetrads, and 3-celled pollen grains. Diploid and polyploid species had high male fertility: both presented relatively high meiotic regularity and therefore formed normal viable spores independently of the ploidy level. Lessingianthus argenteus, the only species with high irregular behavior, might be a neopolyploid species. The eight studied species of the genus presented different percentages of meiotic irregularity at the different phases observed. In diploid specimens the irregularities were concentrated in anaphase of meiosis I, whereas in polyploid specimens the irregularities were dispersed through the phases of meiosis II. The main abnormal behavior identified, and therefore the main mechanisms of unreduced microspore formation, were chromosomes out of plate, bridges without fragments and asynchrony of meiosis I and II. These features broadened the male cytoembryological knowledge of the genus, confirming the suggestion that embryological characters related to male gametophyte development are conserved among the studied species. The results contribute to understand the mechanisms of polyploid formation which is an important process during the evolution of the genus.

Honoring Sabin Berthelot: Nomenclature and botanical history of Berthelotia DC. (Asteraceae, Inuleae)

The genus Berthelotia DC. (presently a synonym of the accepted name Pluchea Cass.), Asteraceae, Inuleae has been regarded as comprising two species, B. lanceolata DC. and B. sericea (Nutt.) Rydb. It honors the French naturalist Sabin Berthelot (1794–1880) for his contribution to the studies of the flora and fauna of the Canary Islands. Under the leadership of Philip B. Webb (1793–1854), Berthelot co-authored the most important work pertinent to the natural history of this archipelago: Histoire Naturelle des Îles Canaries. The nomenclature of Berthelotia and its associated names are revisited here. The holotype of Polypappus sericeus Nutt. (K000974653) was located, and lectotypes were assigned to B. lanceolata (G00450458) and B. lanceolata var. senegalensis DC. (G00452584). Phylogenetic analyses based on nucleotide sequences of the nrDNA ITS were conducted focusing on members of what is known as the Clade J of the Inuleae. A well-supported clade (100% P.P.) that we have labeled as “Clade I” was uncovered, and it is composed of three species that belong to the Pluchea indica Clade plus P. dioscoridis and P. ovalis; but this lineage did not support a previous hypothesis to include P. lanceolata. The two species of Berthelotia did not form a monophyletic group and seem to be distantly related; furthermore, none of these two taxa is sister to Tessaria, a South American genus that has been suggested to be a close relative to Berthelotia. Ethnobotanical uses of B. lanceolata and B. sericea are reviewed.

Single gene mutation in a plant MYB transcription factor causes a major shift in pollinator preference

Understanding the molecular basis of reproductive isolation and speciation is a key goal of evolutionary genetics. In the South American genus Petunia, the R2R3-MYB transcription factor MYB-FL regulates the biosynthesis of UV-absorbing flavonol pigments, a major determinant of pollinator preference. MYB-FL is highly expressed in the hawkmoth-pollinated P.axillaris, but independent losses of its activity in sister taxa P.secreta and P.exserta led to UV-reflective flowers and associated pollinator shifts in each lineage (bees and hummingbirds, respectively). We created a myb-fl CRISPR mutant in P.axillaris and studied the effect of this single gene on innate pollinator preference. The mutation strongly reduced the expression of the two key flavonol-related biosynthetic genes but only affected the expression of few other genes. The mutant flowers were UV reflective as expected but additionally contained low levels of visible anthocyanin pigments. Hawkmoths strongly preferred the wild-type P.axillaris over the myb-fl mutant, whereas both social and solitary bee preference depended on the level of visible color of the mutants. MYB-FL, with its specific expression pattern, small number of target genes, and key position at the nexus of flavonol and anthocyanin biosynthetic pathways, provides a striking example of evolution by single mutations of large phenotypic effect.

Revealing the cryptic diversity of the widespread and poorly known South American blind snake genusAmerotyphlops(Typhlopidae: Scolecophidia) through integrative taxonomy

AbstractMorphological stasis is generally associated with relative constancy in ecological pressures throughout time, producing strong stabilizing selection that retains similar shared morphology. Although climate and vegetation are commonly the main key factors driving diversity and phenotypic diversification in terrestrial vertebrates, fossorial organisms have their morphology mostly defined by their fossorial lifestyle. Among these secretive fossorial organisms, blind snakes of the South American genus Amerotyphlops are considered poorly studied when compared to other taxa. Here, we evaluate the cryptic diversity of Amerotyphlops using phylogenetic and multivariate approaches. We based our phylogenetic analysis on a molecular dataset composed of 12 gene fragments (eight nuclear and four mitochondrial) for 109 species of Typhlopidae. The multivariate analysis was implemented using 36 morphological variables for 377 specimens of Amerotyphlops. Additionally, we contrast our phylogenetic result with the morphological variation found in cranial, external and hemipenial traits. Our phylogenetic results recovered with strong support the following monophyletic groups within Amerotyphlops: (1) a clade formed by A. tasymicris and A. minuisquamus; (2) a clade composed of A. reticulatus; (3) a north-eastern Brazilian clade including A. yonenagae, A. arenensis, A. paucisquamus and A. amoipira; and (4) a clade composed of A. brongersmianus and a complex of cryptic species. Based on these results we describe four new species of Amerotyphlops from north-eastern and south-eastern Brazil, which can be distinguished from the morphologically similar species, A. brongersmianus and A. arenensis.

<i>Corrigendum to</i>: Understanding <i>Praxelis</i> (Asteraceae, Eupatorieae): an updated taxonomy with lectotypifications and morphological and distributional clarifications

The South American genus <i>Praxelis</i> Cass. (Asteraceae, Eupatorieae) includes 18 species and is the second-largest genus of subtribe Praxelinae. It is distributed from Colombia, Venezuela and the Guianas, to central Argentina, southern Brazil and north-western Uruguay. Over the past 40years, one species, <i>P. clematidea</i>, has invaded several countries around the world. To understand <i>Praxelis</i> and its species, this study provides an updated taxonomy with the re-establishment of <i>P. urticeafolim</i> var. <i>nanum</i> as a synonym of <i>P. ostenii</i>, 16 lectotypifications, clarification of morphology and geographical distribution, brief descriptions, and the first key to all the species in the genus.

Phylogenetic position of the relict South American genus Idiopyrgus Pilsbry, 1911 (Gastropoda, Truncatelloidea), with the description of two new cave species

Idiopyrgus is a relict genus of freshwater snails from Brazil traditionally classified in the family Pomatiopsidae. Herein, we use molecular data from newly acquired specimens to test that classification through Bayesian inference phylogenetic analysis. We conclude that Idiopyrgus belongs in the Gondwanan family Tomichiidae, together with the African genus Tomichia and the Australian genus Coxiella. Furthermore, we reassess currently synonymized genus- and species-level names in Idiopyrgus. The genera Hydracme and Aquidauania are considered synonymous with Idiopyrgus. The species I. brasiliensis and I. pilsbryi are restored as accepted species; I. walkeri is considered a taxon inquirendum. Two new species from caves in Bahia state are described herein: Idiopyrgus adamanteussp. nov. and Idiopyrgus minorsp. nov.

Psectrascelis senex sp. nov. (Coleoptera: Tenebrionidae), a new species from the southern Atacama Desert, Chile.

Psectrascelis Solier, 1836 is the most specious South American genus of Nycteliini, which inhabit arid and semiarid regions. Recent expeditions to the southern part of the Atacama Desert collected specimens of Psectrascelis which do not fit with any other described species belonging to this genus. These specimens are morphologically close to P. penai Kulzer, 1955 but the presence of carinae on the elytra easily differentiates this taxon from this mentioned above. Here, we analyzed external morphology, both male and female genitalia, and sequences from a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene with that of morphologically close species. Our study supports the description of Psectrascelis senex sp. nov. and suggests that P. senex sp. nov. is the sister species of P. penai.

Comparative repeatome analysis reveals new evidence on genome evolution in wild diploid Arachis (Fabaceae) species.

Opposing changes in the abundance of satellite DNA and long terminal repeat (LTR) retroelements are the main contributors to the variation in genome size and heterochromatin amount in Arachis diploids. The South American genus Arachis (Fabaceae) comprises 83 species organized in nine taxonomic sections. Among them, section Arachis is characterized by species with a wide genome and karyotype diversity. Such diversity is determined mainly by the amount and composition of repetitive DNA. Here we performed computational analysis on low coverage genome sequencing to infer the dynamics of changes in major repeat families that led to the differentiation of genomes in diploid species (x = 10) of genus Arachis, focusing on section Arachis. Estimated repeat content ranged from 62.50 to 71.68% of the genomes. Species with different genome composition tended to have different landscapes of repeated sequences. Athila family retrotransposons were the most abundant and variable lineage among Arachis repeatomes, with peaks of transpositional activity inferred at different times in the evolution of the species. Satellite DNAs (satDNAs) were less abundant, but differentially represented among species. High rates of evolution of an AT-rich superfamily of satDNAs led to the differential accumulation of heterochromatin in Arachis genomes. The relationship between genome size variation and the repetitive content is complex. However, largest genomes presented a higher accumulation of LTR elements and lower contents of satDNAs. In contrast, species with lowest genome sizes tended to accumulate satDNAs in detriment of LTR elements. Phylogenetic analysis based on repetitive DNA supported the genome arrangement of section Arachis. Altogether, our results provide the most comprehensive picture on the repeatome dynamics that led to the genome differentiation of Arachis species.

Revised Species Delimitation in the Giant Water Lily Genus Victoria (Nymphaeaceae) Confirms a New Species and Has Implications for Its Conservation.

Reliably documenting plant diversity is necessary to protect and sustainably benefit from it. At the heart of this documentation lie species concepts and the practical methods used to delimit taxa. Here, we apply a total-evidence, iterative methodology to delimit and document species in the South American genus Victoria (Nymphaeaceae). The systematics of Victoria has thus far been poorly characterized due to difficulty in attributing species identities to biological collections. This research gap stems from an absence of type material and biological collections, also the confused diagnosis of V. cruziana. With the goal of improving systematic knowledge of the genus, we compiled information from historical records, horticulture and geography and assembled a morphological dataset using citizen science and specimens from herbaria and living collections. Finally, we generated genomic data from a subset of these specimens. Morphological and geographical observations suggest four putative species, three of which are supported by nuclear population genomic and plastid phylogenomic inferences. We propose these three confirmed entities as robust species, where two correspond to the currently recognized V. amazonica and V. cruziana, the third being new to science, which we describe, diagnose and name here as V. boliviana Magdalena and L. T. Sm. Importantly, we identify new morphological and molecular characters which serve to distinguish the species and underpin their delimitations. Our study demonstrates how combining different types of character data into a heuristic, total-evidence approach can enhance the reliability with which biological diversity of morphologically challenging groups can be identified, documented and further studied.

The Malesian species of Dalechampia (Euphorbiaceae)

Dalechampia is a mainly South American genus of generally climbing shrubs with usually sharp stiff trichomes in some of the inflorescence parts. The bisexual inflorescences are very condensed and subtended by two, often showy, large bracts. The three pistillate flowers are separate from the staminate subinflorescence (both groups with their own bracts). The staminate subinflorescence contains groups of staminodial-like bractlets that provide resin for female bees or fragrance for male bees. In west Malesia (Sumatra and Java) one indigenous species is found, the climbing D. bidentata, and occasionally cultivars of the subshrub D. spathulata.

Taxonomy and phylogenetic analysis of the South American genus

The systematics of Philodromidae is far from complete, especially for the Neotropical genera. Among these, Petrichus Simon, 1886 is a poorly known genus restricted to arid and semi-arid environments of South America. In this work, we performed a total-evidence analysis to assess the phylogenetic relationships of Petrichus and revised the taxonomy. Petrichus is monophyletic and closer to Titanebo and the New World Ebo. Within Petrichus, two clades are obtained: the Eremean Clade, containing five species displaying a Neotropical distribution; and the Patagonian Clade, with the seven species inhabiting southern South America. Our results also support a previous hypothesis on the phylogenetic relationships within Philodromidae. Thanatini is monophyletic and includes Fageia and Berlandiella, although this is not statistically supported, whereas Philodromini emerges as paraphyletic. We propose Philodromini be expanded to contain all genera having eyes on tubercles analysed in this work plus the closely related Halodromus, whereas the circumscription of Thanatini should await future phylogenetic analyses with new evidence. As for taxonomic proposals, we synonymise Bacillocnemis Mello-Leitão, 1938 with Petrichus, Petrichus ornatus Schiapelli & Gerschman, 1942 and P. luteus (Nicolet, 1849) with P. junior (Nicolet, 1849), P. lancearius Simon, 1905 with P. tullgreni Simon, 1902; we transfer P. corticinus Mello-Leitão, 1944 to Misumenoides Pickard-Cambridge, 1900 (Thomisidae); and P. fuliginosus (Nicolet, 1849), P. cinereus Tullgren, 1901, P. sordidus Tullgren, 1901 and P. zonatus Tullgren, 1901 are regarded as nomina dubia. In total, 13 species are recognised for the genus, of which four are new (described by Griotti & Grismado): P. spira, from western Argentina, P. patagoniensis, from south-western Argentina, P. roigjunenti, from Argentina and Chile and P. eremicus, from north-central Chile. ZooBank: http://zoobank.org/References/1220255e-6431-45c2-adfe-ed58d1f89b17

Testing the Taxonomy of Amphidorini Leconte (Coleoptera: Tenebrionidae): A Molecular Phylogeny Leveraging Museum Sequencing

The tribe Amphidorini LeConte, 1862, commonly known as the Desert Stink Beetles, is a species-rich group of flightless darkling beetles in the subfamily Blaptinae Leach, 1815 distributed throughout the Western Hemisphere and contains 252 valid species-group taxa within seven genera. In this study we provide molecular phylogenetic analyses based on seven loci to assess both the tribal monophyly and composition of Amphidorini as well as the genus and species-group relationships within the tribe. We find strong support for the exclusion of the South American genus Nycterinus Eschscholtz, 1829 from the rest of the otherwise North American tribe. Nycterinus is recovered in a distantly related clade comprising several Western Hemisphere tribes of Tenebrioninae Latrielle, 1802 and is placed as incertae sedis within that subfamily. Within the remaining 23 genera and subgenera within Amphidorini, 11 were recovered as distinct lineages. The composition and relationships of genera and subgenera of the large genus Eleodes Eschscholtz, 1829 are discussed along with the need for an overhaul in genus-group classification which will likely require the elevation to genus of many current constituent lineages of Eleodes.

Systematic Revision of the Genus Hipalmus Bates, 1870 With Comments on the Placement of Psammetichus dissimilis Peña, 1994 and Zophobas lugubris Boheman, 1858 (Coleoptera: Tenebrionidae: Tenebrioninae)

The South American genus Hipalmus Bates, 1870 (Tenebrioninae: Tenebrionini), distributed in the Pacific coast of Peru and Ecuador, is revised using external morphology and including for the first time details on sexual dimorphism, defensive glands, and male and female genitalia. The genus and its species are redescribed. New distribution records, photographs of the two included species, illustrations of genital features, and distribution maps are provided. A discussion including differences in character states between Hipalmus and Zophobas Dejean, 1834 as well as the tribal placement of Hipalmus in Tenebrionini on the basis of external and internal morphology is also included. The following nomenclatural changes are proposed: Zophobas lugubris Boheman, 1858 is transferred to Hipalmus, Psammetichus dissimilis Peña, 1994 is synonymized under Hipalmus costatus (Guérin-Méneville, 1831) and Hipalmus aequatorius Kolbe, 1901 is synonymized under Hipalmus lugubris (Boheman, 1858) comb. nov.

The genus Symmela Erichson, 1835 (Coleoptera, Scarabaeidae, Sericini): taxonomy and phylogenetic analysis

ABSTRACT The taxonomy of the species of the South American genus Symmela Erichson, 1835 is revised. As a result, we propose the following new synonymies: Symmela longula Erichson, 1835 (= Symmela angustula Moser 1919 syn. nov.), Symmela nitida Erichson, 1835 (= Symmela tenella Erichson, 1835 syn. nov.). Fourteen new species are described: Symmela beskei sp. nov., S. capixaba sp. nov., S. clarki sp. nov., S. erichsoni sp. nov., S. fuhrmanni sp. nov., S. guerlini sp. nov., S. iannuzziae sp. nov., S. martinezi sp. nov., S. nunesorum sp. nov., S. paschoali sp. nov., S. pseudopaca sp. nov., S. reischei sp. nov., S. terezae sp. nov., S. unidentata sp. nov. The lectotypes of the following taxa were designated: Serica flavimana Gory, 1832, Symmela angustula Moser, 1919, S. clypeata Erichson, 1835, S. corumbana Moser, 1921, S. instabilis Erichson, 1835, S. longula Erichson, 1835, S. mutabilis Erichson, 1835, S. nitidicollis Burmeister, 1855, S. opaca Erichson, 1835, S. tarsalis Moser, 1919, and S. tenella Erichson, 1835. Species are redescribed and a key to the species is given; details of external morphological features as well as the aedeagus are illustrated for all taxa. Distribution of the species is shown on a map. A phylogenetic analysis based on 137 morphological characters and parsimony indicates that Symmela is monophyletic. http://www.zoobank.org/urn:lsid:zoobank.org:pub:5147CC1B-6144-4CA4-BA63-E39ED0A20E1C

Systematic revision and phylogeny of Paragripopteryx Enderlein, 1909 (Plecoptera: Gripopterygidae).

Among the Neotropical gripopterygids, the genus Paragripopteryx occurs along the Brazilian Atlantic coast to Uruguay. Since its first recognition by Enderlein in 1909, the genus underwent a confusing taxonomic history with some combinations. In this study, we aim to revise Paragripopteryx and present the first morphology-based phylogeny for the genus. The analysis comprised 38 morphological characters and their respective states in 30 terminal taxa, including 13 Paragripopteryx species, two new species identified as belonging to Paragripopteryx, and 15 outgroup species, among which we can highlight 12 different South American genera and one Australian genus of Gripopterygidae. The cladistic analysis yielded a parsimonious tree for k = 3 (137 steps, consistency index = 0.445, and retention index = 0.591) where most Paragripopteryx are nested, except for Uruguayan Paragripopteryx munoai. We can then infer that in its current circumscription Paragripopteryx is polyphyletic. The following two species are described: Paragripopteryx dasalmas sp. nov. and Paragripopteryx ogum sp. nov. Paragripopteryx baratinii is designated as a nomen dubium. Additionally, we provide a key for species identification, updated geographical records, and illustrations for all species. As a corollary, our study gathers relevant morphological information that can help to better understand this genus and create foundations for the next steps.

The genus Raysymmela Saylor, 1947 (Coleoptera, Scarabaeidae, Melolonthinae, Sericini): taxonomy and phylogenetic analysis

Abstract Here we revise the taxonomy of the South American genus Raysymmela Saylor, 1947 and perform a phylogenetic analysis based on 126 morphological characters. We propose one new synonym, Raysymmela pallipes (Blanchard, 1850) (= Symmela boliviensis Moser, 1919 syn. n.), and three new combinations, Raysymmela costaricensis (Moser, 1924) comb. n., Raysymmela seticollis (Moser, 1921) comb. n., and Raysymmela varians (Erichson, 1847) comb. n. Two new species are described: Raysymmela equatorialis sp. n. (Ecuador) and R. erwini sp. n. (Bolivia). Lectotypes of following taxa were designated: Symmela boliviensis Moser, 1919, S. bruchi Moser, 1924, S. costaricensis Moser, 1924, S. curtula Erichson, 1835, S. pallipes Blanchard, 1850, S. seticollis Moser, 1921, and S. varians Erichson, 1847. Species are redescribed and a key to species is given, external morphological features as well as aedeagus are illustrated for all taxa. Distribution maps as well as a key to currently known South American genera of Sericini are provided. From phylogenetic analysis using parsimony, Raysymmela is not recovered as monophyletic.

Synopsis of the rare genus Alongatepyris (Hymenoptera, Bethylidae), with description of the first extinct species from Dominican amber

Alongatepyris is a South American genus, known only from two species: A. platunissimus and A. ingens. It is a Scleroderminae genus by having the body extremely flattened and the forewing with the first cubital cell very reduced. The first extinct sclerodermine from Dominican amber and first extinct species of Alongatepyris, †A. pedrocai Colombo & Azevedo, sp. nov. is described and illustrated. This species is characterized by having the head elongate, dorsal pronotal area ecarinate and forewing with long 2r-rs&Rs vein. All previously known extant species were analyzed and compared and an updated key for Alongatepyris is also provided. Possible reasons of the absence of strongly flat sclerodermine genera in fossil record outside of the tropical regions are too discussed.

Phylogeny of the South American genus

The genus Baripus Dejean is a carabid beetle endemic to southern South America, inhabiting grassland and shrub habitats in mountain and lowland areas. In this work, the phylogeny of the genus is updated and new species restricted to isolated mountains from the Patagonia Biogeographic Province are described. The cladistic analysis showed that the new mountain species comprise a monophyletic clade with five other species. Within this group, the species are arranged in two internal clades. Each clade contains one or two lowland species with a wide distribution range and the remaining species with microendemic distribution on each mountain system. Their distribution pattern suggests that mountain species of Baripus could have originated since (by) the end of the Cenozoic when the mountains uplifted and acted as a refuge for populations of lowland species that remained isolated and later became differentiated from one another. Based on morphological and cytochrome c oxidase subunit I molecular data, Baripus (Cardiophthalmus) palauco, sp. nov., Baripus (Cardiophthalmus) tromen, sp. nov., Baripus (Cardiophthalmus) aucamahuida, sp. nov. and Baripus (Cardiophthalmus) payun, sp. nov. are described and a key to all currently known species of Baripus (Cardiophthalmus) is provided.