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We describe several proterotheriid remains from the Andalhuala and the Corral Quemado formations (Villavil-Quillay and Santa María basins, Catamarca Province) and the Andalhuala Formation (Santa María Basin at Encalilla, Tucumán Province), Argentina. Neobrachytherium intermedium distinguishes from N. morenoi by the presence of lophoid metaconules in upper molars and astragalus with fusiform attachment for the tibioastragalar ligament, while N. morenoi presents bunoid metaconules and astragalus with ectal facet slightly projected laterally without attachment for the tibioastragalar ligament. ?Proterotherium simplicidens is considered junior synonym of N. intermedium. N. intermedium is circumscribed to levels ca. 6.02 Ma in the Santa María Basin (extendable to ca. 6.88 Ma), to ca. 3.66 Ma in Puerta de Corral Quemado. N. morenoi is restricted to levels above ca. 6.02 to below ca. 4.85 Ma in the Santa María Basin. While other species of Neobrachytherium (i.e. N. ullumense and N. ameghinoi) are distributed in Argentina and Uruguay, N. intermedium and N. morenoi only have records in the late Neogene of northwestern Argentina. These distributions align with earlier hypotheses regarding a regional ecological distinction between the western and eastern regions in the northern half of Argentina during the late Neogene while also fitting the paleophytogeographic provinces (Neotropical and Proto-Spinal). [ABSTRACT FROM AUTHOR]

A Late Holocene (ca. 3,100 to 380 BP) sample of the viscacha rat genus Octomys (Octodontidae) from the Vaquerías Gruta 1 site (VQ-G1) in western Argentina is reported. Phylogenetic and morphometric comparative analyses with living octodontids support that the VQ-G1 sample is related to the desert specialists Tympanoctomys and Octomys , and is sister to the only living species of the latter, O. mimax. The estimated morphological distance to O. mimax is greater than that between pairs of congeneric octodontid species, and even greater than that between some species belonging to different genera. This suggests that the sample represents a new species, whose young age prevents interpreting it as an anagenetic ancestor of O. mimax. If the new species is the result of cladogenesis, its absence in the current fauna represents actual extinction, which among caviomorphs is added to those of † Clyomys riograndensis , † Dicolpomys fossor , † Ctenomys viarapaensis , and † Galea tixiensis —also extinct in the Late Holocene. Thus, the VQ-G1 sample provides evidence of changes in diversity and distribution undergone by small mammals in southern South America during that time. The potential contribution of the Holocene record may be key to elucidate this issue from both an evolutionary and a conservation perspective. This requires a detailed systematic approach to determine whether the taxa under study are truly independent evolutionary units, as well as geographically broad sampling efforts to distinguish the changes affecting distribution from those producing irreversible changes in diversity. [ABSTRACT FROM AUTHOR]

The tick species that comprise the Amblyomma maculatum group (Acari: Ixodidae) are widely distributed in the Nearctic and Neotropical regions, ranging from the United States of America (USA) to Argentina. This group includes three species: Amblyomma maculatum, Amblyomma tigrinum, and Amblyomma triste, which parasitize a high number of vertebrates, including domestic mammals and humans, where they are the main vectors of Rickettsia parkeri s.s. The identification, distribution, and validity of the three species within the group have been controversial and continue to raise questions. Previous studies have mostly focused on the analysis of partial nuclear and mitochondrial genes, highlighting the need for new integrative analyses that contribute to clarifying their systematics and ecology. In this investigation, we obtained the first mitochondrial genome of A. triste (14,808 bp), which, upon comparison with the reported mitochondrial genomes of A. maculatum, exhibits a genetic distance of 4.2%, providing new evidence for the validity of the former species. The order, composition, and structure of the mitogenome of A. triste are consistent with the characteristics reported for most Metastriata including taxa within Amblyomma, that count with several mitochondrial genomes published in the last few years. The attributes of the mitogenomes, such as the absence of paralogs and a small genome, confirm the utility in studies involving complexes of cryptic species as it also serves as a robust tool for inferring phylogenies. Furthermore, we reported new molecular markers at the mitochondrial level which can be used in phylogenetic studies for other tick species, especially those with controversial or challenging taxonomy. We highlight the need of sequencing the mitochondrial genome of A. tigrinum, which is part of the A. maculatum group, as well as experimental crosses of populations from different places in the Americas to obtain additional evidence for species recognition. [ABSTRACT FROM AUTHOR]

The genus Microcavia includes six species of terrestrial, medium-sized, living cavies that occupy arid to semiarid environments at both high and low elevations in western and southern South America. Among these, Microcavia shiptoni is one of the least known species, being recorded only at two isolated localities from northwestern Argentina. Genetic information and a detailed morphological characterization are lacking for this elusive species. In this work, we start filling these gaps by including M. shiptoni in a phylogenetic analysis based on mitochondrial DNA sequences that includes five of the six currently recognized species and place M. shiptoni as sister to M. niata in a clade of highland species. In addition, using both qualitative and quantitative morphological traits, we provided an emended diagnosis for this taxon and a key for the living species of the genus. Finally, we present, the first notes on the natural history of this species. [ABSTRACT FROM AUTHOR]

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We report a new small podocnemidid, Gestemys powelli gen. et sp. nov., based on one nearly complete skull, lower jaw, two shells, and remains of the appendicular skeleton belonging to two specimens from the Eocene Geste Formation of the San Antonio de la Cobres Basin, Salta Province, north-western Argentina. As in other podocnemidid genera, Gestemys exhibits a fully developed and medially extensive cavum pterygoidei, an incisura columellae auris enclosing the stapes and Eustachian tube, and lacks an exoccipital quadrate contact. Gestemys powelli bears a huge foramen palatinum posterius and a short pterygoid flange that does not reach the basisphenoid suture, exposing the cavum pterygoid. Phylogenetic analyses place Gestemys powelli as a member of Podocnemididae more closely related to Erymnochelyinae than Podocnemidinae. In regards to the palaeoenvironmental settings of the Palaeogene formations (Maíz Gordo and Geste) of north-western Argentina, at least two features differentiate the palaeoenvironment where G. powelli was recovered and those of other podocnemidid turtles from the Maíz Gordo Formation: 1) G. powelli was found in situ with very little re-working; and 2) in contrast to the muddy rocks indicating the marginal lacustrine setting and humid climate of the Maíz Gordo Formation, G. powelli is associated with a coarse-grained floodplain setting and a dry, temperate climate. Such differences highlight the contrasting environmental dynamics in which podocnemidid turtles lived during the Palaeogene. [ABSTRACT FROM AUTHOR]

Five new species in the long-jawed orb-weaving spider genus Tetragnatha Latreille, 1804 are described from South America: Tetragnatha amazonica sp. nov. (Venezuela); T. cristata sp. nov. (Argentina and Brazil); T. didorata sp. nov. (Brazil); T. oncognatha sp. nov. (Brazil); and T. pradoi sp. nov. (Argentina and Brazil). A key to the 21 species of Tetragnatha from Argentina and Brazil is provided, completing the revision of the genus for these countries. The female of T. cladognatha Bertkau, 1880 is redescribed and a neotype is proposed, and its male is described for the first time. Additionally, we update the taxonomic status of the following six South American species: Tetragnatha labialis Nicolet, 1849 and T. americana Simon, 1896 are considered new junior synonymies of T. nitens (Audouin, 1826); and Tetragnatha bishopi Caporiacco, 1947, T. linearis Nicolet, 1849, T. similis Nicolet, 1849 and T. sternalis Nicolet, 1849 are proposed as nomina dubia due to missing or juvenile type-material. [ABSTRACT FROM AUTHOR]

A study was performed on a collection of 84 isolates from decaying plant tissues and soils in Argentina previously identified as Trichoderma harzianum. Based on multiple phenotypic characters and multilocus phylogenetic analyses, 10 species were distinguished, three of which are described as new species: T. austroindianum, T. hortense, and T. syagri. Among the remaining seven identified species, the following five can be added to the Argentine mycobiota: T. afarasin, T. afroharzianum, T. endophyticum, T. guizhouense, and T. neotropicale. Trichoderma afroharzianum and T. endophyticum were the most frequent species found in the samples. In addition, a collection of isolates previously identified as T. harzianum with antagonistic abilities were reidentified as T. afroharzianum, thus highlighting the importance of correct identification of biocontrol species. [ABSTRACT FROM AUTHOR]

As part of the transition from Holostei to Teleostei, †Pachycormiformes represent a key group of fishes. However, the anatomy and phylogenetic relationships of the group in the context of the neopterygians are far from being understood. In this contribution we describe a new pachycormiform, †Kaykay lafken gen. et sp. nov., from the Upper Jurassic of Argentina. We made an exhaustive review of morphological characters of holostean and teleostean fishes and explore through a cladistic analysis the phylogenetic relationships of the new species. †Kaykay gen. nov. is retrieved among †Pachycormiformes as being the sister taxon of the macrocarnivorous clade composed of †Orthocormus and †Hypsocormus. Among †Pachycormiformes the pattern of relationships mostly agrees with previous hypotheses, although our study highlights the still poor knowledge of the anatomy of this group. According to our results †Saurostomus is the sister taxon of other toothed pachycormids. †Orthocormus species are recovered as a monophyletic group. The unsolved position of †Pachycormus and †Sauropsis might be a consequence of poor preservation, revealing a lack of understanding of their anatomy. Our phylogenetic analysis also confirms the rapid radiation of holosteans and teleosteomorphs in the Early Triassic and the radiation of pholidophoriforms in the Middle Triassic. †Aspidorhynchoidei radiate in the Early Jurassic. The large ghost ranges (e.g. between †Aspidorhynchoidei and Teleosteomorpha) evidence biases in the fossil record. [ABSTRACT FROM AUTHOR]

We present the first report of Amblycerus dispar (Sharp) attacking stored almonds [Prunus dulcis (Mill.) D. A. Webb] in Argentina. A summarized diagnosis, illustrations, and photographs of the adult and mature larva are provided to facilitate identification. We performed species distribution models for A. dispar and its main host plant Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart. We include A. dispar into a previous morphological character matrix and conduct a phylogenetic analysis to infer its phylogenetic position. The evolution of host plant associations of the genus Amblycerus is herein re-analyzed. A. dispar and its main host shows high suitability areas especially in central-west Argentina and Chile, whereas for the USA, high suitability areas were found for the south-western which include the area of almond production in this country. Although the presence of A. dispar in the USA region is very unlikely, we recommend some awareness as other bruchines are present in the area. Although A. dispar is unlikely to become an economically important risk, monitoring for early detection is recommended to avoid productivity loss, especially when the native host is nearby cultivated areas. A. dispar is hypothesized to be the sister species of A. schwarzi Kingsolver. The colonization of a Rosaceae species is a novelty for this genus, being host shifts known as an important factor affecting both natural and agricultural systems. [ABSTRACT FROM AUTHOR]

Habenaria repens (Orchidaceae) represents a species complex distributed from the southern USA to northern Argentina, including several morphological variants, here referred to as morphotypes. To investigate and clarify the morphological and genetic relationships between these morphotypes and resolve the taxonomy of the complex, we applied a biosystematic multi-population approach using molecular phylogenetic, morphometric and population genetics analyses in the group. We sampled 31 (phylogenetic analyses) and 20 (morphometric and microsatellite analyses) populations of Habenaria aranifera and H. repens from Brazil and the USA, including six morphotypes of H. repens. Bayesian and maximum parsimony phylogenetic analyses of nuclear ribosomal (ITS and ETS) and plastid (matK , trnK and rps16-trnK) markers revealed that the complex is polyphyletic, subdivided into three distantly related clades. Population genetic analyses using microsatellites showed a remarkably similar structure to the phylogenetic analyses, but both were different from the morphometric analyses of floral characters, indicating cases of diversification and convergence, probably due to pollination processes. Habenaria aranifera is embedded in a paraphyletic and polymorphic H. repens with a broad geographical distribution and other attributes of an ochlospecies, probably constituting a progenitor–derivative pair. Our results support the recognition of H. aranifera , H. repens and three or four new species. [ABSTRACT FROM AUTHOR]

We present a systematic review of the extinct species included in the family Caenolestidae, one of the few South American metatherian groups that has survived to the present. We perform a cladistic analysis based on a data matrix consisting of all extant and extinct species that have been referred to this family, 100 morphological characters and two sets of molecular data (cytochrome b and cytochrome c oxidase I). Morphological and molecular data were analysed separately and in combination, under maximum parsimony and maximum likelihood methods. As a result, caenolestids are recovered as a monophyletic group within which we formally recognize three new taxa: Caenolestoides miocaenicus gen. & sp. nov. Gaimanlestes pascuali gen. & sp. nov. and Stilotherium parvum sp. nov. from the Early Miocene of Patagonia, Argentina. Stilotherium is the earliest diverging lineage of caenolestids followed by Gaimanlestes , while C. miocaenicus was recovered as the extinct species most closely related to extant caenolestids. [ABSTRACT FROM AUTHOR]

Two new species of the feather mite genus Trouessartia (Analgoidea: Trouessartiidae) are described from tyrant flycatchers (Tyrannidae) in Argentina: Trouessartia salvadori sp. nov. from the White-crested Tyrannulet Serpophaga subcristata (Vieillot) and T. gonzalezacunai sp. nov. from the Vermilion Flycatcher Pyrocephalus rubinus (Boddaert). Trouessartia salvadori sp. nov. is close to T. longiductaHernandes et Valim, 2015 and most clearly differs from the latter in having, in males, the genital apparatus with wedge-shaped hyaline extensions and the anterior genital papillae situated more distant from the midline than posterior ones, and in females, setae h1 not extending beyond the margin of the interlobar membrane, and the posterior part of the hysteronotal shield bearing well outlined ovate lacunae except in the narrow median area. Trouessartia gonzalezacunai sp. nov. is similar to T. savanaeHernandes, 2014, but is distinguished from that species in having, in males, the terminal lamellae shaped as a fishtail, the epiandrum shaped as a goblet, the apophyses of adanal apodemes represented by thick spine-like tubercles, and in females, setae h1 minute spiculiform about 10 long, and the external copulatory tube shaped as a small rounded tubercle near the margin of interlobar membrane. [ABSTRACT FROM AUTHOR]

Following the results of a maximum parsimony cladistic analysis of 30 terminal taxa against 117 morphologic characters (2978 scorings), the new genus Krateromaspis gen. nov. is described in Neopachylinae. This new genus accommodates three species from Argentina, Brazil and Paraguay, formerly included in Discocyrtus Holmberg, 1878: Krateromaspis antiqua (Soares 1946); Krateromaspis dilatata (Sørensen 1884) and Krateromaspis lata (Mello-Leitão, 1935). All species of Krateromaspis are redescribed, and Discocyrtus invalidus Piza, 1938 is newly considered a junior subjective synonym of Krateromaspis dilatata (Sørensen 1884), this species being quite widespread. The recent inclusion of Opisthoplatus Holmberg, 1878 in Neopachylinae (originally done without a phylogenetic analysis) is corroborated via this study. [ABSTRACT FROM AUTHOR]

The Carrizal Formation, exposed in the Marayes-El Carrizal Basin (western Argentina), has been the focus of palaeobotanical studies since the late 1800s. The recent finding of well-preserved palynological assemblages provides the first detailed studies about its palynofloras. In this paper, the 63 taxa identified in the unit are illustrated and discussed, as well as their stratigraphic distribution in equivalent palynological assemblages of Argentina. Some spore species are revised: Uvaesporites hammenii (Herbst) Césari, comb. nov., Retusotriletes wielandii (Jain) Césari, comb. nov. and Lundbladispora stellae (Herbst) Césari, comb. nov. The recognition of Cadargasporites baculatus de Jersey & Paten emend. Reiser & Williams, Craterisporites rotundus de Jersey, Enzonalasporites vigens Leschik, Leptolepidites argenteaeformis (Bolkhovitina) Morbey, Protodiploxypinus americus Dunay & Fisher and Rugulatisporites permixtus Playford, among others, appears to be useful for local and intercontinental correlations. A Carnian age is proposed for the palynofloras. [ABSTRACT FROM AUTHOR]

Morphological boundaries between species of the maculatipes‐group in the ghost spider genus Sanogasta Mello‐Leitão are ambiguous, and the most widespread species, S. maculatipes, is unusually variable and may represent multiple cryptic species. To resolve these issues, we perform a geometric morphometric analysis on the female genitalia of the group, visualizing and testing for differences in shape between described species, and between putative cryptic species within S. maculatipes. We complement this with a multi‐locus phylogenetic analysis of the group, to place the morphological results in a phylogenetic context. Our study reveals that two species in the group, S. alticola and S. mandibularis, are morphologically and molecularly distinct lineages that can be objectively distinguished. However, we reveal that S. maculatipes actually consists of two widespread sister species which occur in sympatry throughout the grasslands of northern Argentina. We further discover a geographical cline in the shape of the female genitalia of one of these sister species, such that specimens from the east and west of the range display morphological differences comparable to those between species, despite being virtually identical at the COI locus. Our study demonstrates the strength of a geometric morphometric approach for delimiting species in species‐complexes where morphological differences are subtle and confounding factors such as overlapping ranges, allometry and high levels of intraspecific variation are present. [ABSTRACT FROM AUTHOR]

Archangelskyoxylon carlquistii gen. et sp. nov. is based on anatomical secondary xylem from the Lower Jurassic (Sinemurian–Toarcian) in the Roca Blanca Formation of Santa Cruz Province, Patagonia, Argentina. The woods are preserved as siliceous permineralization and examined by light and scanning electron microscopy. The new fossil wood shows a set of anatomical features of the secondary xylem (e.g., vessels with simple, scalariform, foraminate, and modified foraminate perforation plates; vessel with bordered pits with outer aperture vestured or non-vestured, and inner aperture vestured; tracheids with bordered pits; septate fiber-tracheids, and uni to biseriate parenchyma rays), that are related to the Gnetidae and closely resembles those of Gnetum. The new taxon was compared with existing Gnetidae species and included in a phylogenetic analysis to test its relationships with fossil and extant genera of Gnetidae. In the resulting phylogenetic hypothesis, Archangelskyoxylon is placed into a clade that is closely related to Weltwitschia and Gnetum. This finding supports the existence of this lineage in the south of Gondwana during the Jurassic and reinforces the hypothesis that lineages related to the Gnetaceae diverged earlier in South America. • Fossil woods with vessels from the Jurassic of Patagonia have been studied. • The studied fossil corresponds to a new genus, Archangeslskyoxylon. • Wood characters suggest that it has close affinities with Gnetidae. • A phylogenetic analysis was conducted to link the relationships of the new genus. • Plant lineages related to Gnetum were already present in the Jurassic of Gondwana. [ABSTRACT FROM AUTHOR]

The endemic Patagonian genus Titomaya gen. nov. is erected to include the Danian Meretrix chalcedonica (Lefipan and Salamanca formations) and Titomaya longobucca sp. nov. (Salamanca Formation) from the Chubut Province (Argentina). Although Meretrix and Titomaya share the same characteristic sculpture of their nymphs, Titomaya is differentiated by having medium to small, subtriangular, higher than long shells, a narrower and shorter hinge plate, smaller cardinal and anterior teeth, and by the development of a deeper pallial sinus. This new genus rules out the presence of Meretrix in Patagonia, as was long believed, and increases the list of endemic taxa that characterize the Danian assemblages of Patagonia. [ABSTRACT FROM AUTHOR]

We present a new assessment of the genetic and morphological variation within Oxymycterus quaestor Thomas, 1903, which currently includes the junior synonyms O. judex Thomas, 1909 and O. misionalis Sanborn, 1931. We integrate distinct lines of evidence, including variation of mitochondrial (Cytochrome b [ Cytb ]) and nuclear (intron 7 of beta fibrinogen gene [ Fgb ]) sequences, and the assessment of skull quantitative traits based on geometric morphometrics, throughout the Atlantic Forest of Southeastern-Southern Brazil, Argentina, and Paraguay. Phylogenetic relationships based on Cytb indicate that O. quaestor is structured in four well-supported clades (lineages A–D), one of them (lineage C) including topotypes of a previously associated nominal form (O. judex). However, these Cytb lineages exhibit lower levels of differentiation based on the Fgb locus, and are not recovered in the genealogies of this nuclear marker, representing a case of mitonuclear discordance. The Cytb lineages also broadly overlapped in the morphospace both in skull shape and size, which sustain the current wider concept of O. quaestor as one single young species (0.947 Myr) that is recently expanding, and ultimately branching out, in the Atlantic Forest. [ABSTRACT FROM AUTHOR]

Southernmost South America provides significant wintering habitats for migrant shorebirds, most of which breed in the High Arctic tundra. Helminth species parasitizing these migratory birds have been well studied in North America; however, in South America they are poorly known. As part of an ongoing research on the helminth fauna from Patagonian birds in Argentina, we report Notocotylus chionis and Notocotylus sp. (Trematoda: Notocotylidae) parasitizing three shorebird species, the Nearctic migrants Calidris fuscicollis (WRSA) and Calidris bairdii (BASA) (Scolopacidae), and the Neotropical Charadrius falklandicus (TBPL) (Charadriidae). We provide a new morphological description of N. chionis considering that the previous one reported from the snowy sheathbill on Subantarctic islands are incomplete and based on few specimens. We also provided a morphometric characterization of Notocotylus sp. We obtained molecular data which confirmed the identification of specimens recovered from WRSA and TBPL as N. chionis. Phylogenetic analysis based on 28S ribosomal DNA sequences was performed. The results placed N. chionis close to other Patagonian species native to South America (i.e. N. primulus). Notocotylus chionis was found previously in the snowy sheathbill which inhabits in coasts of southern South America, Antarctic Peninsula and surrounding islands. Present finding in resident birds (TBPL) allows us to hypothesize that N. chionis is a Neotropical species whose life cycle is being completed in southern South America and Subantarctic islands and represents a valuable contribution to the knowledge of parasite diversity in the austral subpolar region of the western hemisphere. [ABSTRACT FROM AUTHOR]

Within the Platyhelminthes, Temnocephalida is a clade of continental turbellarians that establish an ectocommensal relationship with their hosts. Many species live associated with decapod crustaceans. In the Neotropical region, two species of Temnocephala are commensals on species of the shrimp family Palaemonidae. Temnocephala digitata lives on Palaemon argentinus and was originally reported from freshwater bodies connected to the Río de la Plata, in Buenos Aires Province, Argentina. The original brief description of the species caused the name to be used incorrectly, creating confusion about the actual specific identity. Here we redescribe T. digitata based on morphological, biological and ecological features. Main morphological features of the reproductive system are the length of the cirrus and its introvert, as well as the number and disposition of its spines. Also, the female portion of the reproductive system lacks vaginal sphincters, which are otherwise well developed in the other species of the genus. The species is big and has the smallest adhesive disk reported for the genus, which allows firm attachment and active movements on the host surface. The egg capsules are fixed on the border of the gill chamber of the host. The prevalence, intensity, and abundance of T. digitata vary according to the size and sex of the host and throughout the year, with the highest prevalence, intensity, and abundance on ovigerous female hosts. This fact is related to the longer intermolt period of ovigerous hosts. These observations conform a solid redescription for a species with a tortuous nomenclatural history. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the pollen morphological diversity among 19 species of the Adesmieae and Aeschynomeneae tribes with the purpose of evaluating their importance for the taxonomical delimitation of the Argentinean species and their systematic significance. Observations and measurements were performed on acetolysed pollen grains. The samples were examined under light and scanning electron microscopes. Principal component analysis (PCA) and conglomerate analysis were performed for quantitative morphological variables. The tribe Adesmieae is stenopalynous while the tribe Aeschynomeneae is eurypalynous; their pollen grains are 3-colporate, and they have lolongate, circular or lalongate endoapertures, semitectate-reticulate or tectate-perforate, fossulate, supra-rugulate exine, small to large size, and suboblate to prolate shapes. A key was made to identify and distinguish species of Adesmia, Aeschynomene, Chaetocalyx, Discolobium, and Poiretia. Exine sculpture and structure, presene of operculum, exine thickness, pollen shape, endoaperture shape, and pollen size all had taxonomic importance to distinguish the species inhabiting Argentina. The groupings recognised in recent classifications are hard to delimit on the basis of the palynological knowledge at this time since there are different pollen types but various of them occur among the three subclades. A framework for future evolutionary analyses within the dalbergioid clade is thus provided. [ABSTRACT FROM AUTHOR]

Hegetotheriidae is one of the most derived families of South American notoungulates, which are known from the late Oligocene to Pliocene. Several genera of hegetotheriids have been described; most of them have been recently re-examined, but the Miocene taxa Hegetotherium and Pachyrukhos have not been revised for more than a century. Numerous species of both genera were described mainly from the Santa Cruz Formation, Santa Cruz Province, but also from the Colhuehuapian beds in Chubut Province, and the Colloncuran beds in Neuquén and Río Negro provinces, Argentina. Recently, Hegetotherium was recorded in Bolivia and Chile. Sinclair was the first reviewer to postulate some synonymies, in the first decade of the twentieth century. The present contribution provides a re-evaluation of these genera, including the study of previously unpublished materials. We conclude that Hegetotherium mirabile and Pachyrukhos moyani are the only hegetotheres in the Santa Cruz Formation (Santacrucian SALMA) with Hegetotherium novum and Pachyrukhos politus in the Colhuehuapian SALMA. Additionally, H. convexum, H. anceps, H. minum and H. andinum are proposed as synonyms of H. mirabile; H. novum is removed from Prohegetotherium; and Hegetotherium arctum is excluded from Hegetotheriidae. This taxonomic revision led to a new phylogenetic analysis of Hegetotheriidae, based on a previous data matrix, but enlarged and corrected, as some taxonomic issues concerning other genera were revealed. The analysis supports the monophyly of Hegetotheriidae and the subfamily Pachyrukhinae, as well as the monophyly of the genera Hemihegetotherium and Paedotherium, if the proposed removal of Pd. kakai from the latter is admitted. In contrast, Hegetotheriinae and Hegetotherium appear to be paraphyletic. The position of H. novum supports its removal from the genus Prohegetotherium, in which it was recently included. [ABSTRACT FROM AUTHOR]

Premise of research. The Río Genoa Formation of Argentine Patagonia hosts Early Permian fossil assemblages that document levels of plant diversity rare among coeval floras. Ongoing work to exhaustively characterize the diversity of these assemblages is key to understanding Permian vegetation and plant evolution. A new fern type identified in the Río Genoa Formation exhibits a novel combination of characters that required taxonomic assessment. Methodology. Observations and measurements of vegetative and reproductive morphology of compression fossils were used in a comparative framework to address the taxonomic placement of the fossils. Pivotal results. The new fern, Floratheca apokalyptika gen. et sp. nov., is characterized by small pinnules with a free base, weakly lobed margin, highly decurrent midvein, and rarely branched lateral veins, as well as radially symmetrical synangia with stellate dehiscence, consisting of six spindle-shaped sporangia. This unique combination of characters distinguishes Floratheca from the more than 25 Permo-Carboniferous marattialean genera known from compressions. Floratheca exhibits variable synangium morphology during development and variation in pinnule base morphology due to a combination of adaxial-abaxial asymmetry of ultimate rachises and taphonomic effects. Conclusions. Floratheca is one of only three late Paleozoic bona fide marattialean compression genera endemic to Gondwana and the second late Paleozoic endemic South American marattialean with preserved fertile structures. Floratheca adds to an increasing diversity of fossils that diminish the disparity between the Southern and Northern Hemispheres, in terms of the extent and intensity of exploration of the plant fossil record, currently skewed taxonomically toward Northern Hemisphere taxa. Variability of synangium and pinnule base morphology in Floratheca cautions against potential taxonomic inflation produced by establishment of new taxa based on small numbers of specimens and incomplete understanding of development and taphonomy. [ABSTRACT FROM AUTHOR]

Several systematic revisions of the Hegetotheriidae have been published in the last twenty years, but some important taxonomic work remains limited to unpublished studies. In one such thesis, the late Oligocene genera Prosotherium and Propachyrucos were revised, so that Prosotherium garzoni and Propachyrucos smithwoodwardi were considered the only valid species for each genus. Later authors loosely accepted these informal revisions, but recent phylogenetic coding has yet to accurately reflect these revisions, with character states often at odds with the known material for these genera. This study re-examines most of the fossil material assigned to Propachyrucos and Prosotherium , including both published and unpublished fossils, and contributes to a better understanding of the systematics, taxonomic diversity and early morphological evolution of the pachyrukhines. We conclude that Prosotherium garzoni and Propachyrucos smithwoodwardi are indeed the only valid species for each genus, confirming the influential but unpublished revisions that have become widely accepted. The known material for these species is clarified to aid future phylogenetic studies. At the same time, Propachyrucos aequilatus and Pr. robustus are herein considered nomina dubia. Additionally, Miocene species originally ascribed to Propachyrucos , along with unpublished material loosely assigned to the same genus, are here synonymized with other genera. Finally, several fossils previously recognized as Prosotherium sp. are here recognized as P. garzoni. [ABSTRACT FROM AUTHOR]

Marmosa subgenus Micoureus contains six currently recognized species, distributed from southern Belize to northern Argentina. Although recent studies have demonstrated the monophyly of the subgenus, the species have not been recently revised. Except for M. phaea , we evaluated the species diversity in this subgenus of mouse opossums using integrated morphological, morphometric and molecular data, with emphasis on M. constantiae. We used a total of 700 specimens for morphological and morphometric analyses. For phylogenetic, species delimitation, molecular variance and population structuring analyses (the latter two only for M. constantiae), we used the mitochondrial cytochrome b gene. Morphometric variation patterns were evaluated through Principal Component Analysis and Discriminant Function Analysis. Our results indicate that there are seven species in our samples. Among the species analysed morphologically, some can be discriminated by craniodental measurements and all can be discriminated through morphology. Marmosa constantiae is polyphyletic, composed of two lineages, one of which is correctly named M. budini. Marmosa constantiae (s.s.) has a well-known genetic structure, with no clear geographic structure and no consistent morphological patterns. Several records of M. demerarae in the literature correspond to M. constantiae. Marmosa demerarae may thus represent a complex formed of at least two species. [ABSTRACT FROM AUTHOR]

A new hydrochoerine rodent, Cardiatherium calingastaense sp. nov. (Caviidae), is described based on the specimen INGEO-PV 87. It was recovered from the late Miocene Las Flores Formation, cropping out at the Puchuzum locality, San Juan Province, Argentina. The new species is based on a particular combination of characters, among which the following can be highlighted: p4 with internal fissures equally deep as in Cardiatherium paranense, secondary external fissure as in Cardiatherium patagonicum, and lacking the fifth internal fissure and supernumerary internal fissure, as in C. paranense; m3 with a conspicuous labial column in the posterior ramus of the second prism; very deep primary and secondary external fissures in upper cheek teeth, the former producing a labial strong step-shaped profile in M2; sagittal crest on the parietals; bullae small in ventral view; scars of the origin of the masseter medialis muscle with an anterior projection up to the level of the incisive foramen and the maxilla-premaxilla suture. The phylogenetic analysis supports the taxonomic proposal of creating a new species of Cardiatherium and shows C. calingastaense sp. nov. as the sister group of the other species of the genus. The lineage leading to the clade Cardiatherium + largest capybaras would have originated at least during the Chasicoan SALMA (early late Miocene). Cardiatherium calingastaense sp. nov. adds to the previous record of Cardiatherium chasicoense and Cardiatherium paranense in the late Miocene of San Juan and Mendoza provinces, respectively, thus increasing the diversity of capybaras in central-west Argentina. [ABSTRACT FROM AUTHOR]

A detailed palynological analysis of the Chacoparaná Basin is presented. Thirty-one samples were recovered from boreholes YCF.CO1, YCF.CO2 and YCF.CO3, corresponding to the lower part of the Ordóñez Formation, at the Santiago Temple locality (Córdoba Province, Argentina). Three new species are described: Calamospora fissurata sp. nov., Retusotriletes archangelskyi sp. nov. and Horriditriletes chacoparanensis sp. nov.; Leiotriletes malanzanensis nov. nom., Endosporites menendezi nov. nom., emend. are proposed to replace L. tenuis Azcuy and E. parvus Menéndez; and the following species are proposed as new combinations: Brevitriletes coalescens (Menéndez & Azcuy) nov. comb., Brevitriletes papillatus (Menéndez & Azcuy) nov. comb., B. sparsus (Menéndez & Azcuy) nov. comb., B. delicatus (Menéndez) nov. comb. and Indotriradites malanzanensis (Azcuy) nov. comb. Two different associations were identified and are compared with the known biozones from the same basin and other biostratigraphical schemes for basins from central western Argentina. The palynological assemblage can be referred, in part, to the Potonieisporites-Lundbladispora Biozone (Chacoparaná Basin) and the Raistrickia densa-Convolutispora muriornata Biozone (central western basins of Argentina, latest Serpukhovian-Bashkirian). [ABSTRACT FROM AUTHOR]

[Display omitted] • A draft genome for two isolates of a new microsporidian are described. • This new microsporidian represents a novel member of the Enterocytozoonida. • The parasite infects two invasive Carcinus spp. on the Argentinian coastline. Carcinus spp. are global aquatic invaders and carriers of several parasites, including a taxonomically unrecognised microsporidian recently observed from Argentina. We provide genome drafts for two parasite isolates, one from Carcinus maenas and one from Carcinus aestuarii , and use multi-gene phylogenetics and genome comparison methods to outline their similarities. Their SSU genes are 100 % similar and other genes have an average similarity of 99.31 %. We informally name the parasite Agmasoma carcini , terming the isolates Ac. var. aestuarii and Ac. var. maenas , following the wealth of genomic data available for each. This study follows on from Frizzera et al. (2021), where this parasite was first histologically identified. [ABSTRACT FROM AUTHOR]

Gastropods are represented in the Early Jurassic of Argentina by Vetigastropoda, Caenogastropoda and Opisthobranchia. The present paper describes nine new vetigastropod species from the Early Jurassic marine deposits of the Neuquén Basin:Proconulus?argentinussp. nov.,Chartronella atuelensissp. nov.,Striatoconulus? axialissp. nov.,Guidonia disciformissp. nov.,Ambercyclus andinussp. nov.,Ambercyclus chilcaensissp. nov.,Discohelix sanicoensissp. nov.,Cryptaenia sudamericanasp. nov. andCryptaenia globosasp. nov. Another three vetigastropods are reported for the first time in this region –Chartronella gradataFerrari,Ataphrus mulanguiniensisFerrari andColpomphalus? aff.musacchioiFerrari – extending their palaeobiogeographical distributions in the Andean region of Argentina.Lithotrochus humboldtii(von Buch),Lithotrochus rothiDamborenea & Ferrari, and an undetermined ataphrid species were also retrieved from marine beds of the Neuquén Basin. A quantitative palaeobiogeographical analysis was performed integrating available data on the entire marine vetigastropod species thus far recorded from Argentina. The primary results of the analysis show two clearly discernible palaeobiogeographical units in the Andean region of Argentina. The local vetigastropod species from the Neuquén and Chubut basins may be interpreted considering palaeogeographical control as a determinant in the distribution of these taxa, including the separate evolution of the Neuquén basin until the late Pliensbachian. However, a shallow marine connection between the Neuquén and Chubut basins along the Palaeo-Pacific seaway during the late Pliensbachian–early Toarcian may explain faunal exchange between both basins at that time. http://zoobank.org/urn:lsid:zoobank.org:pub:EBB37780-8571-4B02-9424-A32E1C2A9AC9 [ABSTRACT FROM PUBLISHER]

Sampling for chytrids in a variety of habitats has resulted in pure cultures that when analyzed have yielded hypotheses of relationships based on molecular and zoospore ultrastructural markers. To extend our understanding of diversity of Chytridiales in eastern Argentina and USA, we isolated and examined the morphology, ultrastructure and 28S and ITS1-5.8S-ITS2 rDNA sequences of numerous chytrids from aquatic habitats from these two regions. Three family-level lineages (Chytridiaceae, Chytriomycetaceae, family incertae sedis) are represented in our molecular phylogeny, and three new genera (Avachytrium, Odontochytrium in Chytriomycetaceae, Delfinachytrium in family incertae sedis) are described. These findings of new genera and species emphasize the potential for discovery of additional diversity. [ABSTRACT FROM AUTHOR]

Abstract: The genus LeptopeltusBernhauer, 1906 (Staphylininae: Staphylinini), distributed from western Venezuela to northwestern Argentina, is revised using characters of external morphology and male and female genitalia. Leptopeltus comprises five species, of which two are described as new: L. carchiensis and L. weyrauchi. Other valid species of the genus are: Leptopeltus flavipennis (Erichson), L. montivagans Bernhauer and L. netolitzkyi Bernhauer. Lectotypes are designated for Leptopeltus flavipennis (Erichson) and L. netolitzkyi Bernhauer. Leptopeltoides gen. nov., from western Colombia and Ecuador, is described for the following four new species: Le. chingazensis, Le. columbiensis, Le. ecuatoriensis and Le. napoensis. Both genera are revised herein, with keys for identification, diagnoses, descriptions, illustrations, a cladogram, and distributional maps. The cladistic analysis shows that Leptopeltus and Leptopeltoides are both monophyletic genera and sister groups and they belong to a natural group of Neotropical genera of Philonthina (Staphylinini). [Copyright &y& Elsevier]

A new hydromedusa species of the genus Bougainvillia (Anthoathecata; Bougainvillidae) is described. Bougainvillia pagesi sp. nov. was collected in shallow coastal waters from southern Brazil (~25-26°S) and northern Argentina (~36-38°S). It differs from other species of the genus mainly by two characters: (i) relatively large size (up to ~20 mm wide and high) and (ii) voluminous folded hanging gonads at perradial walls of the manubrium and extending to the proximal region of the radial canals. Its cnidoma is similar to the other species of the genus, with desmonemes (undischarged capsules: 7.08-10.01 × 2.5-5.59 μm) at marginal tentacles and microbasic euryteles (undischarged capsules: 7.66-11.44 × 2.64-4.43 μm) and smaller (undischarged capsules <2 μm) desmonemes at oral tentacles. [ABSTRACT FROM AUTHOR]

The cycads are an ancient group of seed plants. Fossil stems assigned to the Cycadales are, however, rare and few descriptions of them exist. Here, a new genus of cycad stem, Wintucycas gen. nov., is described on the basis of specimens found in the Allen Formation ( Upper Cretaceous) at the Salitral Ojo de Agua locality, Río Negro Province, Argentina. The most remarkable features of Wintucyas are: a columnar stem with persistent leaf bases, absence of cataphylls, a wide pith, medullary vascular bundles, mucilage canals and idioblasts; a polyxylic vascular cylinder; inverted xylem; and manoxylic wood. The new genus was included in a phylogenetic analysis and its relationships with fossil and extant genera of Cycadales were examined. In the resulting phylogenetic hypothesis, Wintucycas is circumscribed to subfamily Encephalartoideae, supporting the existence of a greater diversity of this group in South America during the Cretaceous. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170, 436-458. [ABSTRACT FROM AUTHOR]

Two new species belonging to the genera Neochromadora and Cobbia from the coastal zone of Patagonia, in the Río Negro and Chubut provinces of Argentina, are described. Neochromadora alejandroi sp. n. is characterised by gubernaculum and spicule shape, the presence of a thick cuticle on subventral tail area, shape of the pharyngeal bulb and length of the cephalic and somatic setae. Cobbia macrodentata sp. n. is characterised by the amphid position, the presence of a large dorsal tooth, the size and length of the cephalic setae, the shape of the gubernaculum which has small hooks at the distal end and the presence of precloacal pores. Keys to the species of both genera are provided. [ABSTRACT FROM AUTHOR]

The Ochodaeidae (Coleoptera: Scarabaeoidea) of Argentina are revised. Previously, two species of Ochodaeinae were known from the country, both in the genus Parochodaeus Nikolajev: P. campsognathus (Arrow) and P. cornutus (Ohaus). An additional 7 species of Parochodaeus from Argentina are described here as new. In addition, Gauchodaeus patagonicus, new genus and new species in the subfamily Chaetocanthinae, is described. This is the first record of the subfamily Chaetocanthinae in South America. Redescriptions, diagnoses, and maps are provided for each species. We also provide a key to genera and a key to species of Parochodaeus of Argentina. With this work, the number of ochodaeid species known from Argentina is increased from 2 to 10. [ABSTRACT FROM AUTHOR]

A new species belonging to the Dothideomycete genus Acanthostigvna is described from bark of two Nothofagus species from Argentina. Its identity as a new species is based on both morphology and molecular sequence data. Acanthostigma patagonica differs from other species in the genus by having larger ascomata and setae and wider, asymmetrical ascospores. An amended key to Acanthostigma species is provided along with a discussion of other species previously described from South America. [ABSTRACT FROM AUTHOR]

The male of Bryophaenocladius carolinae sp. nov. is described and figured. The species can be separated from all other Neotropical species by having a hyaline, blunt triangular anal point, a comparatively small, sub-rectangular inferior volsella, gonostylus widened medially with an outer heel, R4+5 ending opposite to end of M3+4 setose squama and absence of comb on middle tibia and pseudospurs. A key to the adult males of the Neotropical Bryophaenocladius Thienemann is provided. [ABSTRACT FROM AUTHOR]

Abstract: The presence of the calcareous nannofossil Sollasites falklandensis has been recorded in four exploration boreholes in the southeastern Austral Basin at levels assigned an Early to Middle Albian age. This study evaluates its biostratigraphic and paleoceanographic importance for the austral hemisphere and for the Austral Basin in particular. Illustrations and a description of S. falklandensis are provided, and all records are discussed to evaluate its origin and extinction bio-horizons. A Tethyan origin during the Late Aptian is proposed along with a subsequent migration to austral high-latitude regions during the Early Albian. It is believed that S. falklandensis has an affinity for cold surface waters in epicontinental shelf environments. Although it has a diachroneous geographic distribution, it serves as an important marker species in the Early Albian-Middle Albian austral high-latitudes. [Copyright &y& Elsevier]

Three species of Cercophora were found during a survey of the biodiversity of microfungi in northwest Argentina. Cercophora argentina possesses a unique combination of morphological characters and is described as a new species, while C. costaricensis and C. solaris are reported as new records for Argentina. Other species of Cercophora known from this region include C. natalita and C. coprogena, which is fully illustrated for the first time and determined herein to be a synonym of C. californica. All other species are described and illustrated. [ABSTRACT FROM AUTHOR]

A new species of parasitic nematode, Hysterothylacium spirale sp. nov. (Ascaridoidea, Anisakidae), is described based on specimens collected from the intestine and pyloric caeca of the silvery john dory Zenopsis conchifer (Lowe) (Zeiformes, Zeidae), from the Argentinean Shelf (35°05′-40°46′S, 53°03′-58°07′W). Among the 66 valid species described so far in the genus, the new species most closely resembles H. zenis (Baylis, 1929). Both species, apparently specific for fishes of the family Zeidae, share the shape of the dorsal lip, the long expanded lateral alae originating from subventral interlabia and the ornamentation of the tail tip, as well as general morphometry. The combination of these shared features distinguishes both species from all congeners so far known. However, the new species is distinguishable from H. zenis by having shorter interlabia, and consequently the lateral alae originating more posteriorly, shorter spicules, a smaller number of postcloacal papillae and the presence of two pairs of double postcloacal papillae. [ABSTRACT FROM AUTHOR]

Abstract: A new genus and species of clupeomorph fish, Leufuichthys minimus, is described from the fluvial deposits of the Portezuelo Formation, Upper Cretaceous (Turonian–Coniacian) of the Neuquén Group, Patagonia, Argentina. It is a small-sized fish with an estimated body length up to 46mm. Among other characters, the new species shows the following: abdominal scutes; abdomen moderately convex; anal fin elongate-based; three uroneurals; two epurals; caudal fin bearing very elongate rays; and cycloid scales. Leufuichthys minimus gen. et sp. nov. shows a greater similarity with Kwangoclupea dartevellei, a clupeomorph described from a marine Cenomanian deposit of the Democratic Republic of Congo (Africa), mainly due to the presence of an elongate-based anal fin, bearing more than 20 fin-rays, differing from it by the presence of a not hypertrophied abdomen. As far as known, L. minimus gen. et sp. nov. is the first clupeomorph described in the Upper Cretaceous of Patagonia and represents one fortuitous preservation of an articulated fish in fluvial deposits. [Copyright &y& Elsevier]

The phylogeny of Cryptosporella is revised to include recently discovered species. Eight species new to science are described and two new combinations are proposed, raising the total number of species accepted in Cryptosporella to 19. The species delimitation and phylogeny for Cryptosporella are determined based on analyses of DNA sequences from three genes (β-tubulin, ITS and tef1-α), comparative morphology of sexual structures on their host substrate, and host associations. The inferred phylogeny suggests that Cryptosporella has speciated primarily on Betulaceae with 16 species occurring on hosts in that plant family. The host range of most species seems to be narrow with nine species reported from a single host species or subspecies and seven species occurring on plants within a single host genus. A key to species is provided. The known distribution of Cryptosporella is expanded to mountain cloud forests of the provinces of Chiriquí in Panama and Tucumán in Argentina. [ABSTRACT FROM AUTHOR]

This contribution focuses on the diversity of gastropods that lived in the Beagle Channel during the Early and Middle Holocene (from ca. 7500 to 4000 years BP). This temporal framework has special interest because it allowed us to evaluate the colonization process of a relatively recent marine ecosystem, the Beagle Channel (originated 8000–7500 years ago), and the possibility that this channel has represented a 'faunistic corridor' between the Atlantic and Pacific waters of the Magellan Region. Fossil material from four sampling localities was studied; 31 species of gastropods were identified. Additional records of four species of gastropods from six other sites at the Beagle Channel are provided. The fauna described in this work represents the ancestors of the living fauna in the region. In addition, most of these species are also currently found both in the Atlantic and Pacific Magellanic waters, strongly suggesting that the Beagle Channel represented a favourable route for the dispersal of molluscs. [ABSTRACT FROM AUTHOR]

The article discusses a study on the South American dung beetle genus Ennearabdus Lansberge. The descriptions, diagnosis and illustrations for the species of E. lobocephalus are presented which is also the only known species in the genus. A lectotype for Onthophagus lobocephalus Harold is designated and the biology, biogeography, conservation status, and distribution for E. lobocephalus are discussed.

A new species of Akodon (sigmodontine rodents of the tribe Akodontini) is described from the Córdoba Montane Savanna Ecoregion in the eastern mountain ranges of the Sierras Centrales in central Argentina. Phylogenetic relationships among the new species and 11 other species of Akodon were examined using nucleotide sequence data from the entire 1,140 base pairs of the mitochondrial cytochrome-b gene. Maximum-parsimony, maximum-likelihood, and Bayesian analyses found the new species to be distinct from other Akodon and sister to a clade composed of A. spegazzinii, A. boliviensis, and A. oenos. We present analyses of morphological data and descriptions of external, cranial, and dental morphology. This species is relevant to the insular biogeography of the Sierras Centrales, the uniqueness of the ecoregion, and the level of plant and animal endemism in isolated montane regions of central Argentina. [ABSTRACT FROM AUTHOR]

New data on the distribution and systematics of Patagonian species of the scorpion genus Urophonius Pocock 1893 are provided. A species of this genus from Peninsula Valdes in central eastern Argentinean Patagonia, Urophonius martinezi new species, is described. The surface activity period of most of the species of the genus is reviewed and clearly established. A distribution map as well as a key for the Patagonian species of the genus are provided. [ABSTRACT FROM AUTHOR]

The status of thirty four species of the cytheroidean ostracod family Cytheruridae from the Neuquén Basin, west-central Argentina is reviewed. These species belong to the following nine genera: Eucytherura Müller, ranging in this study from Pliensbachian to Valanginian and represented by fourteen species; Kangarina Coryell and Fields, Aalenian–Bajocian, with a single species; Acrocythere Neale, Hauterivian, one species; Paranotacythere Bassiouni, Berriasian, two species; Procytherura Whatley, Pliensbachian to Hauterivian, twelve species; Cytheropteron Sars, Aalenian–Bajocian, one species: Eocytheropteron Alexander, Hauterivian, one species; Paradoxorhyncha Chapman, Aalenian–Bajocian, one species; and Paracytheridea Müller, Berriasian, one species. Of the three subfamilies of the Cytheruridae, the Cytherurinae, with thirty species are by far the most numerous and abundant throughout the study. The other two subfamilies, the Cytheropterinae are represented by three species and the Paracytherideinae by a single species of the nominative genus. Several of the species are very widely distributed geographically and have, for example, also been recorded from Europe; others indicate close links with South Africa and Australia. The stratigraphical ranges of certain genera have been extended as a result of this study. For example, Kangarina has not previously been recorded below the Cretaceous. The Cytheruridae are clearly the most diverse cytheroidean ostracodes in the Mesozoic of the Neuquén Basin and are more diverse than all other groups of ostracodes combined. Four new species, Eucytherura tessae, Eucytherura yunga, Procytherura amygdala and Eocytheropteron immodicus are described. Eucytherura guillaumeae nom. nov. for Eucytherura tuberculata Brenner and Oertli and Eucytherura paranuda nom. nov. for Eucytherura nuda (Brand) are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • We infer the largest phylogeny of Leptophis to date. • Widespread Leptophis ahaetulla sensu lato is composed of multiple species. • Species within L. ahaetulla have evolved distinct color patterns. • Widespread L. depressirostris possibly contains two species. Tetrapod taxa with broad geographic distributions across the Neotropics are often composed of multiple evolutionary lineages. In this paper, we present the most complete phylogeny of Leptophis to date and assess morphology-based species limits within the broadly distributed green parrot snake Leptophis ahaetulla sensu lato, which occurs from Mexico to Argentina. Although L. ahaetulla sensu stricto, L. nigromarginatus and L. occidentalis were recovered as paraphyletic, tree topology tests failed to reject their monophyly. Monophyly of L. bocourti , L. coeruleodorsus , L. cupreus , L. depressirostris , L. marginatus , L. riveti and L. sp. nov. was strongly supported. Our phylogenetic trees support recognition of multiple species within Leptophis ahaetulla sensu lato and suggest that color evolution and the uplift of the Andes played an important role in the diversification of parrot snakes. [ABSTRACT FROM AUTHOR]

One of the best examples of differentiation and hybridization among South American passerine birds is exhibited by Icterus cayanensis (Epaulet Oriole) and Icterus chrysocephalus (Moriche Oriole). Icterus chrysocephalus is a monotypic species restricted to northern South America. Icterus cayanensis is a polytypc species that ranges from Suriname and French Guyana to northern Argentina. Five subspecies are recognized to I. cayanensis. Hybrid zones are known between I. cayanensis and I. chrysocephalus as well as between subspecies of I. cayanenis, even though character variation has never been adequately assessed and mapped. Although molecular data support the hypothesis that I. cayanensis and I. chrysocephalus form a monophyletic group, they do not support the species limits currently recognized within this group. We analysed the geographic variation of plumage characters along the range of this group to map the geographic variation of individual plumage characters and identify the populations that have uniform phenotypic character expression and therefore represent genuine phylogenetic species. We also used molecular data to investigate the phylogenetic relationships among these species. Geographic variation of plumage characters, habitat preferences and molecular data identified four species within I. cayanensis–chrysocephalus clade: an Amazonian species group, formed by I. cayanensis and I. chrysocephalus and a Southern species group composed of I. pyrrhopterus and I. tibialis. The Amazonian species are separated by a relatively narrow hybrid zone along the Amazon valley, whereas the Southern species are separated by a hybrid zone that is larger than the ranges of the two species individually. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95, 583–597. [ABSTRACT FROM AUTHOR]