Western Ecuador Research Articles

Variation in avian morphology along a short tropical elevational gradient

AbstractPatterns across species of intraspecific phenotypic variation with environment can shed light on the underlying drivers of adaptive evolution. Phenotypic variation within a species along tropical elevational gradients is of particular interest because species with narrow elevational ranges may still experience considerably varied environmental conditions. Here, we examine morphological variation in 27 tropical bird species, spanning 11 families and 3 orders, across a 675 m elevational gradient in Western Ecuador. We analyzed a data set of six morphological variables in 3263 individual birds using multivariate analyses of variance (MANOVAs) and canonical correlation analyses (CCAs). We found that morphology varies significantly with elevation in 8 species, and that spatial segregation by age or sex was apparently not responsible for this result. The phenotypic traits that varied with elevation varied strongly by species. To the best of our knowledge, morphological variation over equally short elevational and horizontal distances across a diverse suite of vertebrate species has not previously been demonstrated.Abstract in Spanish is available with online material.

Dioscorea magnibracteata (Dioscoreaceae), a new species from western Ecuador based on the unpublished work of Temple Clayton

Dioscorea magnibracteata is described and formally presented as a new species based on specimens identified with unpublished names by Temple Clayton. This species occurs exclusively in the seasonally deciduous dry tropical forest of coastal Ecuador, a fairly threatened environment. This new species is monoecious and features staminate flowers with six stamens but differs markedly from all other species of Neotropical Dioscorea by the staminate inflorescences with very large cymbiform bracts and toothed to lacerated margin. We provide a morphological description as well as information on habitat, geographic distribution and taxonomic comments that include the morphological delimitation of the new species and similarities to other species of Dioscorea sect. Monadelpha.

Use of artificial nest boxes by two species of small, arboreal mammals in ecuadorian tropical dry forest

ABSTRACT The nest structure of two species of small mammals, Marmosa simonsi and Rhipidomys latimanus were recorded for the first time. Nests were found inside artificial nest boxes in a tropical dry forest remnant ecosystem in Western Ecuador. We described the nests and categorized them as rearing nest, permanent resting nest and transient refuge, depending on their intended use. Artificial nest boxes provide an optimal place for pup rearing and resting for these small mammals. These nest sites can be useful for ecological studies of behavior and habits of elusive, poorly-known mammalian species.

Phylogeography of the Chocó Endemic Rainbow Characin (Teleostei: Rhoadsia)

South America's Chocó, part of the North Andean Pacific Slopes–Rio Atrato ecoregion, is a biodiversity hotspot with many disjunct rivers, yet phylogeographic and population genetic studies of the Chocó's aquatic species are scarce. Rhoadsia is a Chocó endemic freshwater fish genus with two recognized species: R. minor from the upper Esmeraldas River drainage and R. altipinna from the lower Guayas River drainage, Ecuador. Little is known about the evolutionary history of Rhoadsia, and due to morphological similarities, the validity of the two nominal species has been questioned. We conducted a phylogeographic study using two mitochondrial genes and 12 microsatellite markers to examine the evolutionary history of Rhoadsia and the validity of its two species. Samples collected in drainages throughout western Ecuador from sea level to 1260 m.a.s.l. were included, as were samples of species in the closely related genera Parastremma and Carlana from Colombia and Central America. Phylogenetic analysis of the mtDNA markers confirmed the reciprocal monophyly of a northern and southern clade, and the presence of mitochondrial haplotypes of both clades in the northern Guayas basin. Structure analysis with the microsatellite markers pointed to introgression at the border between the species ranges as the likely cause of the mixing of mitochondrial haplotypes in the northern Guayas. Bayesian analysis of the microsatellite data revealed the existence of ten populations throughout western Ecuador, divided into three main geographically segregated groups. Group I coincided with the northern distribution of R. minor, while groups II and III seemed to represent geographic subgroups of R. altipinna in the Guayas and southern coastal drainages. Patterns of genetic divergence and diversity support the recognition of multiple evolutionarily significant units within both species and allowed reevaluation of previously reported freshwater biogeographic zones in the Ecuadorian Chocó. This study provides a baseline for future studies examining freshwater biogeographical patterns throughout the Ecuadorian Chocó, as well as a phylogeographic framework to examine the genetic basis of adaptation of morphologically divergent populations of Rhoadsia inhabiting Andean mountain streams in the region.

Divergence times of the Rhoadsia clade (Characiformes: Characidae)

Abstract The family Characidae is the most diverse group of fishes in the Neotropics with challenging systematics. The three genera Carlana, Parastremma, and Rhoadsia, formerly considered the subfamily Rhoadsiinae, are now included in the subfamily Stethaprioninae. Previous phylogenetic analyses did not include all genera of Rhoadsiinae, specifically Parastremma. Here, we estimated the phylogenetic relationships and divergence times of the genera of Rhoadsiinae (the Rhoadsia clade) relative to the most representative genera of the Characidae. We used six molecular markers from the mitochondrial and nuclear genome to estimate the phylogeny and divergence times. We confirmed the monophyly of the Rhoadsia clade. Furthermore, we estimated that the Central American genus Carlana and the western Colombian genus Parastremma diverged approximately 13 Mya (95% HPD 8.36–18.11), consistent with the early-closure estimates of the Isthmus of Panama (~15 Mya). The genus Rhoadsia, endemic to Western Ecuador and Northern Peru, was estimated to originate at around 20 Mya (95% HPD 14.35–25.43), consistent with the Andean uplift (~20 Mya).

Small non-volant mammals from Bosque Protector Cerro Blanco, a fragment of tropical dry forest in western Ecuador

Basic diversity studies of small non-volant mammals are scarce in western Ecuador, evidencing a knowledge gap regarding the mammalian fauna in the region. These organisms play key roles in important ecological processes and may be affected by several anthropogenic factors. Herein we report the results of a rapid assessment of marsupials and rodents of Bosque Protector Cerro Blanco (Guayas province), a fragment of dry forest surrounded by urban development. Between October 2016 and March 2017, we trapped rodents and marsupials with Sherman and Tomahawk live traps; also, we conducted direct observations and searched for skeletal remains. We recorded nine species of small non-volant mammals, seven native and two invasive. The marsupial Marmosa simonsi was the most frequently captured species. We reported three previously unrecorded species for this reserve: Sigmodon peruanus, Aegialomys baroni, and Rhipidomys latimanus. We recommend continued monitoring of the mammalian fauna of Cerro Blanco using alternative techniques such as pitfall traps, canopy live traps, and analysis of owl pellets. These efforts will permit a better understanding of the marsupial and rodent assemblage in this important site for biodiversity conservation in coastal Ecuador, a region that unfortunately faces intense human pressure.

A NEW SPECIES PREVIOUSLY CONFUSED WITH Caecilia pachynema (GÜNTHER, 1859) (AMPHIBIA: GYMNOPHIONA: CAECILIIDAE) FROM THE CORDILLERA CENTRAL OF COLOMBIA

Caecilia pachynema is a distinctively colored species known from western Ecuador and supposedly from a remote population in the northern Cordillera Central of Colombia. Previously it had been detected that the Colombian populations of "C. pachynema’’ were likely an undescribed species. Material gathered over the past twenty years allows us to describe this new species and restrict the known distribution of C. pachynema to Ecuador.

Malvaceae neotropicae novae vel minus cognitae X. New species of Quararibea from Colombia and Ecuador

In this advance of the taxonomic revision that is being carried out in the genus Quararibea (Malvaceae) for the north of South America, three new species are described in this contribution, which are compared morphologically with the species considered related in each case. A first, Q. cornejoi, known from the wet forests of western Ecuador that we associate with Q. grandifolia and Q. casasecae, taxa also distributed in the Pacific corridor of Ecuador and Colombia. A second species, Q. latilimbata, from the sub-Andean forests of the Central Cordillera of the Department of Antioquia, Colombia, related to the previous species and to the Amazonian species Q. duckei. All of them with an unusual trait in the genus, an androecium with the long staminal branches. Finally, Q.villanuevae, from the dry forests of the upper Magdalena Valley in the Department of Tolima, Colombia, associated with the Andean species Q. foenigraeca and Q. caldasiana. These last three species, which have androecium with smaller staminal branches, are assigned to a different morphological group. Illustrations and detailed photographs of the new species are included as well as keys to the identification of the treated species.

Isolated petrosal of the extinct sloth Glossotherium tropicorum (Xenarthra, Folivora, Mylodontidae) from the island of Trinidad

This report is the first to identify the presence of the extinct ground sloth Glossotherium tropicorum from Pleistocene-aged tar pit deposits in Trinidad. G. tropicorum is known primarily from extensive skeletal material recovered from the Pleistocene of western Ecuador and Peru. Our identification is based on an isolated left petrosal bone, which exhibits a variety of derived diagnostic features of mylodontid sloths in general, e.g., the presence of an epitympanic recess, and the genus Glossotherium in particular, including a reduced anteroventral process of the tegmen tympani. This represents only the second published record of the genus Glossotherium from outside continental South America, and is a substantial range extension for the species G. tropicorum. The present study also represents the first published description of a mylodontid sloth fossil from Trinidad. The specimen is part of a collection that was initially documented in an unpublished Master’s thesis, and that includes additional sloths and other Pleistocene mammals. This fauna confirms the presence of extensive savanna-type habitats on Trinidad during the Pleistocene, and is consistent with the presence of a land bridge connection between the island and mainland South America at that time.

First Case of Gynandromorphism in the Orchid-Bee Eulaema meriana (Olivier) (Hymenoptera: Apidae)

The discovery of the first case of gynandromorphism in Eulaema meriana (Olivier) is described and illustrated. A specimen from Los Ríos, western Ecuador, discovered in the Instituto Nacional de Biodiversidad (MECN) collection, exhibits mostly male features on the left and female features on the right, except for the jugal comb of the hind wing and terminalia. This finding is compared to other reported cases in orchid bees.

Interannual variations in the hydrodynamics of a tropical river-wetland system: a case study for the Abras de Mantequilla wetland, Ecuador

Wetlands are sensitive to hydrological conditions and human influence. The Abras de Mantequilla wetland (AdM) located at the centre of the Guayas River Basin (Western Ecuador), was declared a Ramsar site (2000) due to its important role in the conservation of bird fauna diversity. The wetland also supports significant populations of fish, including endemic species. The area exhibits two seasons: (i) a wet season (January–May); and (ii) a dry season (June–December). For the area of interest data is scarce, and a hydrodynamic model did not exist. In order to evaluate the interannual hydrodynamics and inundation patterns variability of this wetland system, a 2D hydrodynamic model was developed using the Delft3D software suite. Local knowledge was combined with field observations and expert elicitation to construct an appropriate model for the area. Results show that the Abras de Mantequilla is a river-wetland system that experiences extreme variations in hydrodynamic conditions from low water depths and almost stagnant conditions during the dry season, to a very dynamic behaviour during the rainy season. The inundation area ranges between 5 to 27 km2, water depths vary from 0.4 to 9 m and flow velocities from 0.0 up to 0.9 m/s. The “Nuevo River” is the main inflow to the wetland, with an overall contribution of about 85–90%, with peak discharges during February and March. A numerical tracer analysis indicated that the wetland can be divided into three main areas (upper, middle and low), with higher residence times found in the middle area. Overall, based on numerical hydrodynamic simulations it was possible to obtain adequate indications of the relative importance of the different river inflow conditions, as well as spatial and temporal inundation patterns, velocities and residence times under hydrological conditions varying from dry to extremely wet years. Furthermore, the hydrodynamic model provides a basis for other studies such as water quality assessment and primary production dynamics, as well as for determining the habitat suitability for fish.

Preliminary phytochemical screening for antioxidant activity and content of phenols and flavonoids of 18 species of plants native to western Ecuador

The phytochemical screening, total phenolics and flavonoids content and antioxidant activity of plants native to western Ecuador were investigated to provide the basic information for further studies towards the discovery of new compounds. The species studied were Adenostemma platyphyllum Cass, Castilla elastica subsp . gummifera (Miq.) C.C. Berg., Cochlospermum vitifolium (Willd.) Spreng., Ectozoma pavonii Miers, Erythrochiton giganteus Kaastra & A.H. Gentry, Erythroxylum patens Ruiz ex O.E.Schulz, Ficus brevibracteata W.C. Burger, Ficus tonduzii Standl., Grias ecuadorica Cornejo & S.A. Mori, Handroanthus billbergii subsp . ampla (Bureau K. Schum.) S.O. Grose, Morisonia americana L., Operculina codonantha (Benth.) Hallier f., Passiflora macrophylla Spruce ex Mast., Podandrogyne jamesonii (Briq.) Cochrane, Pradosia montana T.D. Penn., Tecoma castaneifolia (D.Don) Melch, Urera baccifera (L.) Gaudich. ex Wedd., and Xanthosoma sagittifolium (L.) Schott.The highest percentage of inhibition of DPPH• was found in E. patens (92.41%). Most of the extracts evaluated exhibited antioxidant activity.

Success in conserving the bird diversity in tropical forests through private protected areas in Western Ecuador

Private protected areas have recently attained more importance at a worldwide level as regards nature conservation. Particularly, the specific region of Western Ecuador receives hardly any protection from the State, and private reserves could, therefore, be a suitable tool to ensure the preservation of its forests and their associated wildlife biodiversity. In this work, we compare the bird species richness between private reserves and public protected areas (managed by the State) located in this region. We also show a checklist of bird species found in the Buenaventura Reserve, a private reserve located in south-western Ecuador. Our comparison shows that smaller private reserves may harbour a similar number of bird species than larger protected areas managed by the state, and they have a higher number of bird species per area. In particular, a total of 233 different bird species were registered in Buenaventura, which were distributed in 16 orders and 42 families. Three species were classified as endangered at an international level: El Oro Parakeet (Pyrrhura orcesi), El Oro Tapaculo (Scytalopus robbinsi), and the Grey-backed Hawk (Pseudastur occidentalis), and another three at a national level: the Long-wattled Umbrellabird (Cephalopterus penduliger), the Slaty-winged Foliage-gleaner (Philydor fuscipenne), and the White-vented Plumeleteer (Chalybura buffonii). Therefore, private reserves can be appreciated as a suitable conservation tool for bird conservation, and they should not be undervalued because of their smaller size. Buenaventura Reserve is a good example of how private reserves are extremely important in fragmented landscapes, as is the case with tropical forests in Western Ecuador.

Records of chromatic disorder in Molossus molossus and Sturnira bakeri (Chiroptera) from western Ecuador

Herein we report cases of leucism in Molossus molossus and Sturnira bakeri from three locations of lowlands of western Ecuador, which include three gravid females, five juvenile, four subadult, and six adults. The M. molossus specimens showed white spots on several parts in the soft part of body (ears, tragus, propatagium, uropatagium), and fur (throat, abdomen), while individual of S. bakeri presented a whitish-yellowish patch on its dorsal region, very contrast in yellow-shoulder bats. Although South America has a significant information gap about chromatic disorders in bats, been necessary to continue reporting cases of chromatic disorders to try to determine their causes.

Flower abundance and defendability at two mass-blooming understory plants structure nectar-feeding bird guilds in garúa forest of western Ecuador

Mutualistic interactions, such as animal pollination, structure biodiversity in the Neotropics. In coastal montane garúa (fog) forests of Ecuador, 2 mass-blooming plants attract up to 17 species of nectar-feeding birds, especially hummingbirds. We describe avian guilds and behavior at the 2 mass bloomers and use mist-netting capture rates to test 3 predictions: (1) capture rates of territorial hummingbirds will increase with flower abundance on the mass bloomer they defend, (2) hummingbirds known to mainly use other flowers will show no change in capture rate during mass blooms, and (3) field observations of interspecific interactions will be reflected in capture rates. We statistically modeled capture rates of bird species, species richness, and Shannon Diversity Index in response to flower abundance on the 2 mass bloomers during 16 flowering seasons (1996–2013). Capture rates of 8 nectar-feeding species increased significantly with increased abundance of white-flowered Psychotria hazenii blooms, while only one species, Speckled Hummingbird (Adelomyia melanogenys), increased significantly in response to red-flowered Stenostephanus clarkii flower abundance, and aggressively defended these flower patches. Violet-bellied Hummingbird (Damophila julie) showed the strongest capture rate response to increased abundance of P. hazenii flowers, and was the dominant territorial hummingbird around these shrubs. Endangered Esmeraldas Woodstars (Chaetocercus berlepschi) and Little Woodstars (Chaetocercus bombus) visited both mass bloomers, but had a statistically significant increase only with P. hazenii highest flower abundance suggesting that restoration to recover endangered woodstars will benefit more from plantings of P. hazenii than S. clarkii. We conclude that flower abundance and defendability structure avian pollinator networks at these mass bloomers more so than nectar quality, quantity, or secretion rates, all of which were similar.

Comparison between terrestrial mammals in evergreen forests and in seasonal dry forests in Western Ecuador: should efforts be focused on dry forests?

Abstract The Coast Region of Ecuador has been dramatically deforested, and most of the remaining natural vegetation is formed of fragmented patches, in which there is little knowledge of wild mammal populations. The objective of this study was to assess the presence and detection rate (DR) of medium and large-size mammals by using camera-traps in fragmented forests located outside the protected areas comparing the two main types of forest: seasonal dry and evergreen. We registered 18 different species, of which four had greater DRs in dry forests (Lycalopex sechurae, Odocoileus peruvianus, Simosciurus stramineus and Sylvilagus daulensis), four were more detected in evergreen forests (Cuniculus paca, Dasyprocta punctata, Dasypus novemcinctus and Procyon cancrivorus), and the remaining 10 species had no significant habitat preference. The mean species richness was similar in both ecosystems, but the number of detections was greater in the evergreen forests. Finally, two of the region’s four threatened species had higher DRs in dry forests. These results suggest that it is necessary to conserve both types of ecosystems to ensure the conservation of all mammals’ species. However, since dry forests are less protected and their threatened fauna suggests that conservation efforts should be particularly focused on them.

A new species of Cynomops (Chiroptera: Molossidae) from the northwestern slope of the Andes

Abstract The systematics and taxonomy of the broadly distributed bats of the genus Cynomops has changed considerably in the last few years. Among the major changes, Cynomops abrasus was split into two species of large-bodied forms (Cynomops mastivus and C. abrasus) distributed east of the Andes. However, large Colombian specimens identified as C. abrasus from the western side of the Andes had yet to be included in any revisionary work. Phylogenetic analysis performed in this study, using mtDNA sequences (Cytochrome-b), revealed that these Colombian individuals are more closely related to Cynomops greenhalli. Morphological and molecular data allowed us to recognize populations from western Colombia, western Ecuador and northwestern Peru, as members of a new species of Cynomops. Characters that allow for its differentiation from C. greenhalli include a larger forearm, paler but more uniform ventral pelage, more globular braincase, and well-developed zygomatic processes of the maxilla (almost reaching the postorbital constriction). This study serves as another example of the importance of including multiple lines of evidence in the recognition of a new species. Given its rarity and the advanced transformation of its habitat, this new species is particularly important from a conservation perspective.

Pleistocene climatic fluctuations promoted alternative evolutionary histories in Phytelephas aequatorialis, an endemic palm from western Ecuador

AbstractAimPleistocene (2.58 Ma–11.7 ka) climatic fluctuations have shaped intraspecific genetic patterns worldwide; however, their impact on species in many regions remains unknown. In order to determine the impact of Pleistocene climatic fluctuations on the tropical rain forests of western Ecuador, we explored the evolutionary history of the endemic palm Phytelephas aequatorialis.LocationWestern Ecuador, north‐western South America.TaxonPhytelephas aequatorialis (Arecaceae).MethodsOne hundred and seventy‐six nuclear genes were sequenced in 91 individuals for phylogenomic and population structure analyses. The time of divergence between identified genetic lineages was estimated using a coalescent phylogenomic analysis. Palaeoecological niche modelling analyses were performed to determine areas of historical climatic suitability since the Last Glacial Maximum (LGM; 22 ka) that potentially acted as forest refugia during the Pleistocene. A Wilcoxon test and Pearson correlations were used to explore how current levels of genetic diversity, in terms of expected heterozygosity (Hs), have been shaped by several palaeoclimatic and geographic factors.ResultsPhylogenomic and population structure analyses revealed two main genetic lineages with a north–south distribution, which diverged 1.14 Ma during the Pleistocene. Two potential Pleistocene refugia were identified, one along the Pacific coast of Ecuador and one in the Andean foothills of south‐western Ecuador. The location of these refugia agrees with the spatial location of the two genetic lineages. Within the Andean foothills, Hs was lower for the southern lineage than for the northern lineage. Hs significantly increased with decreasing latitude across the species as a whole.Main conclusionsPleistocene climatic fluctuations promoted intraspecific divergence in P. aequatorialis within the rain forests of western Ecuador. The Andean foothills of south‐western Ecuador could be an important area for rain forest evolution because they potentially remained climatically suitable throughout the Pleistocene. Lower genetic diversity in the southern lineage, which apparently remained isolated in the Andean foothills during glacial cycles, adds evidence to the presence of a forest refugium in south‐western Ecuador. The geographic pattern in genetic diversity suggests that P. aequatorialis colonized western Ecuador from the north. This study supports the role of Pleistocene climatic fluctuations in promoting intraspecific divergence, and for the first time, we show their impact west of the Andes.

<strong>Two new species of <em>Monteverdia</em> (Celastraceae) from Ecuador</strong>

This contribution describes two new species of Monteverdia restricted to western Ecuador. Monteverdia multicostata Cornejo & Biral, from wet forests of Esmeraldas and Manabí provinces, is easily distinguished from all other known Monteverdia species by having the largest fruits in the genus (to 3.5 cm long) and by its unusual multi-ridged seeds. Monteverdia zakii Biral & Cornejo, from the Montane Andean forests of Pichincha, is characterized by the unique combination of: lenticellate twigs, coriaceous leaves with inconspicuous secondary veins and a large fruit with a truncate base. This set of characters distinguishes it from the related M. macrocarpa (Ruiz & Pav.) Biral.

Cuantificación de Plomo (Pb) en tejidos blandos y óseo de murciélagos (Mammalia: Chiroptera) provenientes de zonas de influencia Urbana en la costa occidental de Ecuador

ABSTRACT Lead (Pb) has generated a worldwide concern for its genotoxic effects on human health, and its ability to be bioaccumulative in ecosystems, but nevertheless, there are no estimates of wildlife from terrestrial habitats in Ecuador. Our objective was to determine the concentration of Pb in soft and bone tissues from bats species collected in areas with urban influence in Guayas province, western Ecuador. The specimens were collected with mist nets, manual capture from animals found dead or dying in the streets, and museological collections. We applied Mann-Whitney U test to analyze differences between males and females, and between guilds. 66 chiropterans were analyzed, distributed in 14 species, where 98.5% presented Pb in its body. The nectarivore guild showed highest Pb concentrations than insectivores and frugivores. In the analysis of sexes, no significant differences were found in soft tissue of Glossophaga soricina, Artibeus lituratus, A. aequatorialis and Molossus molossus. Museological samples made possible to detect Pb in several synanthropic species. Finally, Pb should be considered an emerging threat for bats due its possible genotoxic effects over populations.