Amalophyllonmiraculum (Gesneriaceae), an exceptionally small lithophilous new species from the western Andean slopes of Ecuador.

Recent exploratory field expeditions to the western slopes of the Ecuadorian Andes resulted in the discovery of a new species of Amalophyllon (Gesneriaceae). Amalophyllonmiraculum J.L.Clark, sp. nov. is described from two localities in the Centinela region in the Santo Domingo de los Tsáchilas province. The new species is differentiated from congeners by the pendent habit, basal rosette of leaves, leaf blades with deeply serrate margins, and miniature size. Based on IUCN guidelines, a preliminary conservation status is assigned as Critically Endangered (CR).

ResumenRecientes expediciones exploratorias de campo a las laderas occidentales de los Andes ecuatorianos dieron como resultado el descubrimiento de una nueva especie de Amalophyllon (Gesneriaceae). Amalophyllonmiraculum J.L.Clark, sp. nov. se describe de dos localidades de la región de Centinela en la provincia de Santo Domingo de los Tsáchilas. La nueva especie se diferencia de otros congéneres por el hábito colgante, la roseta basal de las hojas, las láminas foliares con márgenes profundamente aserrados y su tamaño en miniatura. Según las directrices de la UICN, se le asigna el estado de conservación preliminar de En Peligro Crítico (CR).

Evolution of intraspecific floral variation in a generalist-specialist pollination system.

Intraspecific processes impact macroevolutionary patterns through individual variation, selection, and ecological specialisation. According to the niche variation hypothesis, the broader ecological niche of gen- eralist species results in an increased morphological variation among individuals, either because they are constituted of diversified specialised individuals each exploiting a fraction of the species' niche, or because they are constituted of true generalist individuals that experience relaxed selection. To test this hypoth- esis, we surveyed the individual floral morphology of species of Antillean Gesneriaceae, a group that has transitioned between specialisation for hummingbird pollination and generalisation multiple times throughout its evolutionary history. We characterised the profiles of corollas using geometric morpho- metrics and compared the intraspecific shape variance of specialists and generalists in a phylogenetic context. We used three approaches that differently accounted for the high dimensionality of morphologi- cal traits, the ancestral reconstruction of pollination syndromes over time, and the error associated with the estimation of the intraspecific variance. Our findings provide partial support for the niche variation hypothesis. If considering the whole shape in the analysis corroborated this idea, decomposing the shape into principal components indicated that not all aspects of the corolla exhibit the same pattern of vari- ation. Specifically, pollination generalists tend to display greater intraspecific variation than specialists in terms of tubularity, but not of curvature. Accounting for the error in the variance estimation also reduced the support for the hypothesis, suggesting that larger sample sizes may be required to reach stronger conclusions. This study emphasises the reciprocal influence between plants and their pollinators on floral morphology at different biodiversity scales, and suggests that ecological strategies of species can affect patterns of morphological variation at macroevolutionary scales.

Gesneriatuberifera (Gesneriaceae), a new lithophytic species from the Sierra de Bahoruco, Barahona Peninsula of southern Hispaniola (Dominican Republic).

A narrowly endemic new species of Gesneria is described from the Sierra de Bahoruco in the Dominican Republic's Barahona Peninsula of southern Hispaniola. Gesneriatuberifera J.L.Clark & T.Clase, sp. nov. differs from all other congeners by the presence of a tuber and tubular red corollas with yellow lobes. Images and a discussion are provided to summarize the presence of tubers in other Gesneriaceae and differentiate Gesneriatuberifera from congeners that share a lithophytic habit. Based on IUCN guidelines, a preliminary conservation status of Endangered (EN) is assessed for G.tuberifera.

ResumenSe describe una nueva especie de Gesneria endémica de la Sierra de Bahoruco en la península de Barahona en la República Dominicana, en el sur de La Española. Gesneriatuberifera J.L.Clark & T.Clase, sp. nov. se diferencia de todos los demás congéneres por la presencia de un tubérculo y corolas rojas tubulares con lóbulos amarillos. Se proporcionan imágenes y una discusión para resumir la presencia de tubérculos en otras Gesneriaceae y diferenciar a Gesneriatuberifera de otros congéneres que comparten un hábito litófito. Con base en las pautas de la UICN, se evalúa un estado de conservación preliminar de En Peligro (EN) para G.tuberifera.

Bomareapastazensis (Alstroemeriaceae), an exceptionally small new species from the eastern Andean slopes of Ecuador.

Recent field research on the eastern slopes of the Andes resulted in the discovery of a new species of Bomarea from the Cerro Candelaria Reserve in the Tungurahua province of Ecuador. Bomareapastazensis is the second smallest species in the genus and differs from the smallest by the presence of glutinous trichomes on the ovary, glabrous sepals, and greenish-yellow petals with purple spots. Based on IUCN guidelines, a preliminary conservation status is assigned as Vulnerable (VU).

ResumenRecientes investigaciones de campo en las estribaciones orientales de los Andes dieron como resultado el descubrimiento de una nueva especie de Bomarea en la Reserva Cerro Candelaria en la provincia de Tungurahua en Ecuador. Bomareapastazensis es la segunda especie más pequeña del género y se diferencia por la presencia de tricomas glutinosos en el ovario, sépalos glabros y pétalos verdes con amarillo y manchas moradas. Con base en los lineamientos de la IUCN, se le asigna un estado preliminar de conservación de Vulnerable (VU).

Amanoacondorensis (Phyllanthaceae), a new shrubby species from the Cordillera del Condor in southern Ecuador.

A new species of Amanoa (Phyllanthaceae) is described from the sandstone Nangaritza Plateau in the Cordillera del Cóndor Region in southern Ecuador. Amanoacondorensis J.L.Clark & D.A.Neill is a small tree, 4 m tall that is only known from the type collection. The new species is distinct by a shrub habit, presence of coriaceous leaves with an acuminate apex, and congested inflorescences. The relatively high elevation of the type locality, presence of an androphore, and the habit as shrub or low tree are an unusual combination for Amanoa. The conservation status of A.condorensis is assessed as Critically Endangered (CR), based on IUCN Criteria.

ResumenSe describe una nueva especie de Amanoa (Phyllanthaceae) de la meseta de arenisca de Nangaritza en la región de la Cordillera del Cóndor en el sur de Ecuador. Amanoacondorensis J.L.Clark & D.A.Neill es un pequeño árbol de 4 metros de altura que sólo se conoce de la colección tipo. La nueva especie se distingue por la presencia de inflorescencias congestionadas, hojas coriáceas con ápice acuminado, y porte arbustivo. La elevación relativamente más alta de la localidad tipo, la presencia de un andróforo, y el hábito de arbusto o árbol pequeño son una combinación inusual para Amanoa. El estado de conservación de A.condorensis se evalúa como En Peligro Crítico (CR) según los Criterios de la UICN.

Glossolomamagenticristatum (Gesneriaceae), a new species from the Cordillera Oriental of the Colombian Andes.

A narrowly endemic new species of Glossoloma is described from the Cordillera Oriental of the northern Andes, in the Colombian departments of Caquetá and Huila. Glossolomamagenticristatum J.L.Clark, D.Hoyos & Clavijo, sp. nov. differs from most other congeners by a habit that is usually epiphytic with elongate scandent subwoody shoots, the presence of a magenta corolla tube, and a creased calyx formed by tightly appressed adjacent lobes. A brief summary of Gesneriaceae diversity in the Colombia departments of Caquetá and Huila is discussed with an emphasis on the old highway between Florencia and Guadalupe. The conservation status of G.magenticristatum is assessed as Endangered (EN) based on IUCN Criteria.

ResumenSe describe una especie de Glossoloma endémica de la Cordillera Oriental de los Andes del norte, en los departamentos de Caquetá y Huila. Glossolomamagenticristatum J.L.Clark, D.Hoyos & Clavijo, sp. nov. se diferencia de otras especies en el género por el hábito usualmente epífito con ramas alargadas, escandentes y subleñosas, el tubo de la corola magenta, y un cáliz con los lóbulos estrechamente adpresos y con margen ondulada. Se presenta una breve síntesis de la diversidad de Gesneriaceae en los departamentos de Caquetá y Huila, con un énfasis en la vieja carretera entre Florencia y Guadalupe. Se evalúa el estado de conservación de G.magenticristatum y se propone que se debería categorizar como En Peligro (EN), de acuerdo a los criterios de la UICN.

Rediscovery of Gasteranthusextinctus L.E.Skog & L.P.Kvist (Gesneriaceae) at multiple sites in western Ecuador.

We report the rediscovery of the Critically Endangered cloud forest herb Gasteranthusextinctus, not seen since 1985. In 2019 and 2021, G.extinctus was recorded at five sites in the western foothills of the Ecuadorian Andes, 4-25 km from the type locality at the celebrated Centinela ridge. We describe the species' distribution, abundance, habitat and conservation status and offer recommendations for further research and conservation efforts focused on G.extinctus and the small, disjunct forest remnants it occupies.

Two new species of Drymonia (Gesneriaceae) from Northwestern South America, including the discovery of the longest flower known in the genus.

Two new species, Drymoniaintermedia Clavijo & J.L.Clark, sp. nov. and D.longiflora J.L.Clark & Clavijo, sp. nov. (Gesneriaceae, Columneinae), are described from the western Andean slopes of Ecuador and Colombia. The new species are similar to D.fimbriata, D.laciniosa, D.macrophylla, and D.peponifera because of the facultative epiphytic habit, deeply serrate to laciniate calyx margins, and fleshy bivalved capsules with tardily dehiscent endocarps. Leaves with brochidodromous venation, narrowly elongate corolla tube, and laciniate calyx margins differentiate D.intermedia. The longest corolla of any known Drymonia (> 6.5 cm long) differentiates D.longiflora. Digital photographs, geographic distributions, and IUCN categories are provided for the new species.

ResumenSe describen dos especies nuevas de Drymonia (Gesneriaceae, Columneinae) de la vertiente occidental de los Andes ecuatorianos y colombianos: Drymoniaintermedia Clavijo & J.L.Clark, sp. nov. y D.longiflora J.L.Clark & Clavijo, sp. nov. Las nuevas especies son similares a D.fimbriata, D.laciniosa, D.macrophylla y D.peponifera por ser epífitas facultativas, con márgenes de los lóbulos del cáliz fuertemente aserradas a laciniadas y los frutos en cápsulas carnosas con endocarpos de dehiscencia tardía. D.intermedia se diferencia por las hojas con venación broquidódroma, el tubo de la corola estrechamente elongado y los lóbulos del cáliz laciniados. D.longiflora se diferencia por tener la corola más larga hasta ahora reportada para el género (> 6.5 cm de largo). Se presentan láminas fotográficas, distribuciones geográficas y categorías de amenaza de la UICN para las especies nuevas.

Monopyleglutinosa (Gesneriaceae), a new species from the western slopes of the Ecuadorian Andes.

Exploratory field expeditions to the western slopes of the Ecuadorian Andes resulted in the discovery of a new species of Monopyle (Gesneriaceae). Monopyleglutinosa J.L.Clark & Keene, sp. nov. is described as a narrow endemic from lowland forests along the border of the Reserva Ecológica Los Illinizas in the Province of Cotopaxi. The new species is unique for the presence of glutinous or sticky trichomes on the calyx lobes and outer surface of the inferior ovary. Based on IUCN guidelines, a preliminary conservation status is assigned as Critically Endangered (CR).

ResumenLas expediciones a los bosques de las laderas noroccidentales de los Andes de Ecuador dieron como resultado el descubrimiento de una nueva especie: Monopyleglutinosa J.L.Clark & Keene, sp. nov., la cual es endémica de una reducida área en el borde de la Reserva Ecológica Los Illinizas en la provincia de Cotopaxi. La nueva especie es única por la presencia de tricomas glutinosos o pegajosos en los lóbulos del cáliz y la superficie externa del ovario ínfero. Basados en los criterios de la UICN, se asigna un estado de conservación preliminar de En Peligro Crítico (CR).

Two new pendulous epiphytic Columnea L. (Gesneriaceae) species from the Chocó forests of the Northern Andes.

Exploratory field expeditions to the Chocó forests in the northwestern slopes of the Ecuadorian and Colombian Andes resulted in the discovery of two new species of Columnea (Gesneriaceae). Columneafluidifolia J.L.Clark & F.Tobar, sp. nov., is described as a narrow endemic from Bosque Protector Mashpi and surrounding areas in the province of Pichincha in northern Ecuador. Columneapendens F.Tobar, J.L.Clark & J.F.Sm., sp. nov., is described from recently discovered populations in the provinces of Carchi and Santo Domingo de los Tsáchilas (Ecuador) and the departments of Cauca and Nariño in southwestern Colombia. The two new species are pendent epiphytes with elongate shoots and shallowly bilabiate to nearly tubular corollas. Descriptions, complete specimen citations, and a distribution map are provided. Based on IUCN guidelines, a preliminary conservation status of Critically Endangered (CR) is provided for C.fluidifolia and Endangered (EN) is provided for C.pendens.

ResumenLas expediciones de campo a los bosques del Chocó en las laderas noroccidentales de los Andes de Ecuador y Colombia dieron como resultado el descubrimiento de dos nuevas especies de Columnea (Gesneriaceae). Columneafluidifolia J.L.Clark & F.Tobar, sp. nov., descrita como endémica de una reducida área del Bosque Protector Mashpi y zonas circundantes en la provincia de Pichincha. Columneapendens F.Tobar, J.L.Clark & J.F.Sm., sp. nov., se describe a partir de poblaciones recientemente descubiertas en las provincias de Carchi, Santo Domingo de los Tsáchilas (Ecuador) y los departamentos de Cauca y Nariño en el suroeste de Colombia. Las dos nuevas especies son epífitas pendulares con brotes alargados y corolas ligeramente bilabiadas a casi tubulares. Descripciones, citaciones completas de los especímenes y mapa de distribución son incluidas. Basados en los criterios de la IUCN, se asigna un estado de conservación preliminar de En Peligro Critico (CR) para C.fluidifolia y a C.pendens se le asigna la categoría de En Peligro (EN).

Glossolomawiehleri (Gesneriaceae), a new species from the northwestern Andes of Ecuador.

A new species of Glossoloma is described from the western Andean slopes of the Pichincha Province in northern Ecuador. Glossolomawiehleri J.L.Clark & Tobar is differentiated from all other congeners by an epiphytic habit, elongate scandent shoots that exceed four meters in length, and coriaceous leaves with a velutinous indument on the lower leaf surface. The new species is illustrated, featured with field images from recent expeditions, and assigned the category of Endangered (EN) according to IUCN Criteria.

ResumenSe describe una nueva especie de Glossoloma de las laderas occidentales de la provincia Pichincha en el norte de Ecuador. Glossolomawiehleri J.L.Clark & Tobar se diferencia de todos sus otros congéneres por su hábito epífito, ramas escandentes alargadas que superan los cuatro metros de longitud y hojas coriáceas con un indumento velutino en la superficie inferior de la hoja. La nueva especie se ilustra con imágenes de campo de expediciones recientes y se le asigna la categoría de En Peligro (EN) de acuerdo a los criterios de la IUCN.

Three new species of Columnea (Gesneriaceae) from the western Andean slopes of Ecuador and Colombia.

Three new species of Columnea (Gesneriaceae, tribe Gesnerieae) are described from the western Andean slopes of northern Ecuador and southern Colombia. Columneaangulata J.L. Clark & F. Tobar and Columneafloribunda F. Tobar & J.L. Clark are described from northern Ecuador. Columneatecta J.L. Clark & Clavijo is described from southern Colombia and northern Ecuador. The three new species are facultative epiphytes with dorsiventral shoots and are readily recognized by bright red tips on the abaxial and adaxial leaf surfaces. The species described here are vegetatively similar to the sympatric species Columneapicta H. Karst. and are readily differentiated by floral features that are illustrated, described and featured with digital images.

AbstractSe describen tres especies nuevas de Columnea (Gesneriaceae, tribu Gesnerieae) originarias de la vertiente occidental de los Andes de Ecuador y Colombia. Columneaangulata J.L. Clark & F. Tobar y Columneafloribunda F. Tobar & J.L. Clark se describen del norte de Ecuador; Columneatecta J.L. Clark & Clavijo se describe del sur de Colombia y norte de Ecuador. Las tres especies nuevas son epífitas facultativas con vástagos dorsiventrales, las cuales se reconocen fácilmente por las puntas de las hojas de color rojo brillante en ambas superficies; son vegetativamente similares y simpátricas con Columneapicta H. Karst., pero se pueden diferenciar por las características florales que se ilustran, describen y detallan con imágenes digitales en este artículo.

New circumscriptions add two northern Andean species to Kohleria (Gesneriaceae).

Recent studies of type specimens and exploratory research expeditions in the northern Andes have resulted in an updated circumscription and recognition for two species of Kohleria (Gesneriaceae) in Ecuador and Colombia. A change in the rank from a variety to species is recognized for Kohleria anisophylla (Fritsch) Wiehler. The combination Kohleria andina (Fritsch) J.L. Clark & Jost, comb. nov. is provided here and a lectotype is designated. The updated circumscriptions of these two species are supported by morphology and geographic distribution. The presence of an epiphytic habit for Kohleria is discussed. Field images based on recent expeditions are provided to support the circumscriptions presented here.

ResumenLos estudios recientes de las colecciones tipo y las expediciones exploratorias en el norte de los Andes han dado como resultado la actualización en la circunscripción y reconocimiento de dos especies de Kohleria (Gesneriaceae) en Ecuador y Colombia. Se reconoce el cambio de rango de variedad a especie para Kohleria anisophylla (Fritsch) Wiehler. Se presenta la nueva combinación Kohleria andina (Fritsch) J.L. Clark & Jost, comb. nov. con la designación de su lectotipo. La circunscripción actualizada de estas dos especies está soportada por caracteres morfológicos y distribución geográfica. Se discute la presencia del hábito epífito en Kohleria. Se presentan imágenes obtenidas en las expediciones de campo para soportar las circunscripciones propuestas aquí.

Greater pollination generalization is not associated with reduced constraints on corolla shape in Antillean plants.

Flowers show important structural variation as reproductive organs but the evolutionary forces underlying this diversity are still poorly understood. In animal-pollinated species, flower shape is strongly fashioned by selection imposed by pollinators, which is expected to vary according to guilds of effective pollinators. Using the Antillean subtribe Gesneriinae (Gesneriaceae), we tested the hypothesis that pollination specialists pollinated by one functional type of pollinator have maintained more similar corolla shapes through time due to more constant and stronger selection constraints compared to species with more generalist pollination strategies. Using geometric morphometrics and evolutionary models, we showed that the corolla of hummingbird specialists, bat specialists, and species with a mixed-pollination strategy (pollinated by hummingbirds and bats; thus a more generalist strategy) have distinct shapes and that these shapes have evolved under evolutionary constraints. However, we did not find support for greater disparity in corolla shape of more generalist species. This could be because the corolla shape of more generalist species in subtribe Gesneriinae, which has evolved multiple times, is finely adapted to be effectively pollinated by both bats and hummingbirds. These results suggest that ecological generalization is not necessarily associated with relaxed selection constraints.

Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae.

The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates. We identified a high frequency of pollinator transitions, including reversals to insect pollination. Diversification rates of the group increased through time since 25 Ma, coinciding with the evolution of hummingbird-adapted flowers and the arrival of hummingbirds in South America. We showed that plants pollinated by hummingbirds have a twofold higher speciation rate compared with plants pollinated by insects, and that transitions among functional groups of pollinators had little impact on the diversification process. We demonstrated that floral specialization on hummingbirds for pollination has triggered rapid diversification in the Gesneriaceae family since the Early Miocene, and that it represents one of the oldest identified plant-hummingbird associations. Biotic drivers of plant diversification in the Neotropics could be more related to this specific type of pollinator (hummingbirds) than to shifts among different functional groups of pollinators.

Resolving incongruence: Species of hybrid origin in Columnea (Gesneriaceae).

Speciation by hybridization has long been recognized among plants and includes both homoploid and allopolyploid speciation. The numbers of presumed hybrid species averages close to 11% and tends to be concentrated in a subset of angiosperm families. Recent advances in molecular methods have verified species of hybrid origin that had been presumed on the basis of morphology and have identified species that were not initially considered hybrids. Identifying species of hybrid origin is often a challenge and typically based on intermediate morphology, or discrepancies between molecular datasets. Discrepancies between data partitions may result from several factors including poor support, incomplete lineage sorting, or hybridization. A phylogenetic analysis of species in Columnea (Gesneriaceae) indicated significant incongruencies between the cpDNA and nrDNA datasets. Tests that examined whether one or both of the datasets had the phylogenetic signal to reject the topology of the alternate dataset (Shimodaira and Hasegawa [SH] and approximately unbiased [AU] tests) indicated significant differences between the topologies. Splitstree analyses also showed that there was support for the placement of the discrepant taxa in both datasets and that the combined data placed the putative hybrid species in an intermediate position between the two datasets. The genealogical sorting index (GSI) implied that coalescence in nrDNA had occurred in all species where more than a single individual had been sampled, but the GSI value was lower for the cpDNA of most of the putative hybrids, implying that these regions have not yet coalesced in these lineages despite being haploid. The JML test that evaluates simulated species pairwise distances against observed distances also implies that observed nrDNA data generate shorter distances than simulated data, implying hybridization. It is most likely that C. gigantifolia, C. rubriacuta, and C. sp. nov. represent a lineage from a hybrid ancestor, but C. moorei may be a more recent hybrid and may still be undergoing hybridization with sympatric species.

Speciation within Columnea section Angustiflora (Gesneriaceae): islands, pollinators and climate.

Despite many advances in evolutionary biology, understanding the proximate mechanisms that lead to speciation for many taxonomic groups remains elusive. Phylogenetic analyses provide a means to generate well-supported estimates of species relationships. Understanding how genetic isolation (restricted gene flow) occurred in the past requires not only a well-supported molecular phylogenetic analysis, but also an understanding of when character states that define species may have changed. In this study, phylogenetic trees resolve species level relationships for fourteen of the fifteen species within Columnea section Angustiflorae (Gesneriaceae). The distributions of sister species pairs are compared and ancestral character states are reconstructed using Bayesian stochastic mapping. Climate variables were also assessed and shifts in ancestral climate conditions were mapped using SEEVA. The relationships between morphological character states and climate variables were assessed with correlation analyses. These results indicate that species in section Angustiflorae have likely diverged as a result of allopatric, parapatric, and sympatric speciation, with both biotic and abiotic forces driving morphological and phenological divergence.