Track analysis of the Mexican species of Buprestidae (Coleoptera): testing the complex nature of the Mexican Transition Zone

Aim  We analysed the geographical distributions of species of Buprestidae (Coleoptera) in Mexico by means of a panbiogeographical analysis, in order to identify their main distributional patterns and test the complex nature of the Mexican Transition Zone, located between the Nearctic and Neotropical regions.
Location  Mexico.
Methods  The geographical distributions of 228 species belonging to 33 genera of Buprestidae were analysed. Localities of the buprestid species were represented on maps and their individual tracks were drawn. Based on a comparison of the individual tracks, generalized tracks were detected and mapped. Nodes were identified as the areas where generalized tracks converged.
Results  Thirteen generalized tracks were obtained: one was restricted to the Mexican Transition Zone and five to the Neotropical region (Antillean and Mesoamerican dominions), a further two occurred in both the Nearctic region (Continental Nearctic dominion) and the Mexican Transition Zone, and a further five in both the Neotropical region (Mesoamerican dominion) and the Mexican Transition Zone. Seven nodes were identified at the intersections of the generalized tracks – in the Mesoamerican dominion (Mexican Pacific Coast, Mexican Gulf and Chiapas biogeographical provinces) and the Mexican Transition Zone (Trans-Mexican Volcanic Belt, Balsas Basin and Sierra Madre Oriental biogeographical provinces).
Main conclusions  We conclude that the geographical distribution of Buprestidae is mainly Neotropical, corresponding to the Mesoamerican dominion and the Antillean dominion of the Neotropical region, and the Mexican Transition Zone. Most of the generalized tracks and nodes correspond to the Mexican Transition Zone, thus confirming its complex nature. We suggest that the nodes we have identified could be particularly important areas to choose for conservation prioritization.     

Areas of endemism and distribution patterns for Neotropical Piper species (Piperaceae)

Aim The study aimed to establish areas of endemism and distribution patterns for Neotropical species of the genus Piper in the Neotropical and Andean regions by means of parsimony analysis of endemicity (PAE) and track‐compatibility analysis. Location The study area includes the Neotropical region and the Northern Andean region (Páramo‐Punan subregion). Methods We used distribution information from herbarium specimens and recent monographic revisions for 1152 species of Piper from the Neotropics. First, a PAE was attempted in order to delimit the areas of endemism. Second, we performed a track‐compatibility analysis to establish distribution patterns for Neotropical species of Piper. Terminology for grouping Piper is based on recent phylogenetic analyses. Results The PAE yielded 104 small endemic areas for the genus Piper, 80 of which are in the Caribbean, Amazonian and Paranensis subregions of the Neotropical region, and 24 in the Páramo‐Punan subregion of the Andean region. Track‐compatibility analysis revealed 26 generalized tracks, one in the Páramo‐Punan subregion (Andean region), 19 in the Neotropical region, and six connecting the Andean and Neotropical regions. Both the generalized tracks and endemic areas indicate that distribution of Piper species is restricted to forest areas in the Andes, Amazonia, Chocó, Central America, the Guayana Shield and the Brazilian Atlantic coast. Main conclusions Piper should not be considered an Andean‐centred group as it represents two large species components with distributions centred in the Amazonian and Andean regions. Furthermore, areas of greater species richness and/or endemism are restricted to lowland habitats belonging to the Neotropical region. The distribution patterns of Neotropical species of Piper could be explained by recent events in the Neotropical region, as is the case for the track connecting Chocó and Central America, where most of the species rich groups of the genus are found. Two kinds of event could explain the biogeography of a large part of the Piper taxa with Andean–Amazonian distribution: pre‐Andean and post‐Andean events.     

Biogeographical affinities among Neotropical cloud forests

 Biogeographical affinities among cloud forests in the Neotropical region were studied through a track approach, by constructing generalised tracks based on the results of a parsimony analysis of endemicity (PAE). Distributional data on 946 genera and 1,266 species of vascular plants (Pteridophyta, angiosperms, and gymnosperms) from 26 cloud forest patches from Colombia, Costa Rica, Cuba, Honduras, Jamaica, Mexico, Peru, Puerto Rico, and Venezuela were analysed; and four localities from eastern and western United States were also included as outgroups. The track analysis identified six generalised tracks: a first one that includes the majority of the cloud forests of Mexico, Central America, the Antilles, and northern Colombia; a second one that includes southern Mexico and northern Central America; a third one that includes the mountains in northwestern South America; a fourth one that includes the mountains in southwestern South America; and two others in western and eastern United States. It is concluded that the Neotropical cloud forests are closely related and that those of the Caribbean subregion exhibit complex relationships, which could be due to the complex tectonic history of the area. Received February 22, 2001 Accepted May 1, 2001     

The diversification of Nearctic mammals in the Mexican transition zone

The boundary between the Nearctic and Neotropical regions has been delineated using different approaches, methods and taxa. Using a panbiogeographical approach, identification of nodes can help understand the dynamics and evolution of the boundary. We analysed the distribution patterns of 46 Mexican land mammal species belonging to the Nearctic biotic component and delineated generalized tracks and nodes, in order to determine the southernmost boundary of the Nearctic region in Mexico. We found six generalized tracks and nine nodes; the latter located largely in the Sierra Madre Oriental, Transmexican Volcanic Belt, Sierra Madre del Sur and Chiapas biogeographical provinces. The highlands of Chiapas were found to represent the southernmost area inhabited by Nearctic taxa. The other biogeographical provinces, together with the Sierra Madre Occidental and Balsas Basin provinces, represent the Mexican transition zone in the strict sense. Instead of a classic static boundary, this transition zone represents an evolutionarily 'active' zone, where several speciation events have taken place in the past.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 327–339.     

Genetic relationships among American species of the genus Prosopis (Mimosoideae, Leguminosae) inferred from ITS sequences: evidence for long-distance dispersal

Aim  The genus Prosopis includes 44 species and has a pseudoamphitropical, disjunct distribution. We aimed to determine whether American Prosopis sections arose in North or South America, and to explain the current distribution of their species on the basis of their genetic relationships.
Location  South-western USA, Mexico, Caribbean Antilles, Peru–Ecuador, central and northern Argentina, south-western Argentina (Patagonia) and Cuyo, south-western Asia and northern Africa.
Methods  Internal transcribed spacer fragments from 21 species of Prosopis were sequenced and the data were used to analyse the phylogenetic relationships using Microlobius and Mimosa as outgroups. Genetic distances were calculated to estimate the degree of divergence. Dispersal–vicariance (DIVA) analysis was conducted to help understand the biogeographical history of the genus.
Main conclusions  The sections Strombocarpa and Algarobia are not monophyletic. Prosopis argentina (section Monilicarpa ) and the species of Algarobia are included in single clade. The phylogeny, DIVA analysis, and the pattern of genetic distances indicate that the ancestral area for the American species was wide, from south-western USA to Central and northern Argentina. Successive vicariance events split this area, and long-distance dispersal episodes (perhaps mediated by birds) led to recolonizations from North to South America, and vice versa .     

Areas of endemism and spatial diversification of the Muscidae (Insecta: Diptera) in the Andean and Neotropical regions

Aim We present a biogeographical analysis of the areas of endemism and areas of diversification in the Muscidae. This analysis searched for geographical patterns in the Muscidae to reconstruct elements of the evolutionary biogeographical history of this insect family. Location Andean and Neotropical regions. Method We constructed a geographic database of 728 species from the literature and museum specimens. Areas of endemism were established by parsimony analysis of endemicity (PAE) based on grids of two different sizes: 5° (550 × 550 km) and 2° (220 × 220 km). Areas of diversification were delimited by track analysis that also included phylogenetic information. This process was independently applied to 11 genera. For each genus, we plotted generalized tracks generated by sister species on a map. When these generalized tracks supported inter‐generic nodes they were manually contoured and inferred to be areas of diversification for the Muscidae. Results Thirteen endemic areas were found using the 5° grid, and eight endemic areas resulted from the 2° grid. Ten areas were in agreement with previous studies, and 11 were new. Amazonian and Atlantic areas of diversification agreed with previous areas for the genus Polietina, and new areas of diversification were found in Panama and in central Chile. Main conclusions Six spatial patterns in the Muscidae were identified: (1) areas of endemism in both Pampa and Puna provinces were established with species whose distributions had not previously been analysed; (2) a new area of endemism was established in extreme southern South America, in Tierra del Fuego; (3) two new areas of diversification, which include Panama and central Chile, were identified; (4) a spatial association was identified between the separation of Chiloe Island from the continent and the diversification in Andean species; (5) a north–south track axis and latitudinal node intervals were identified, interpreted as spatial responses to glaciation or glacial retreat in the Andes; and (6) a spatial coincidence of areas of endemism, of diversification and high species richness in the Muscidae was discovered. The analysis of a complete database and the recognition of areas of diversification are extremely important in elucidating novel biogeographical patterns, which will in turn contribute to a better understanding of the geographical patterns of evolution in the Muscidae.     

Taxonomy and phenotypic relationships of the Anastrepha fraterculus complex in the Mesoamerican and Pacific Neotropical dominions (Diptera,Tephritidae)

Previous morphometric studies based on linear measurements of female structures of the aculeus, mesonotum, and wing revealed the existence of seven morphotypes within the Anastrepha fraterculus cryptic species complex along the Neotropical Region. The current research followed linear and geometric morphometric approaches in 40 population samples of the nominal species Anastrepha fraterculus (Wiedemann) spread throughout the Meso-American and Pacific Neotropical dominions (including Mexico, Central America, Venezuela, Colombia, Ecuador, and Peru). The goals were to explore the phenotypic relationships of the morphotypes in these biogeographical areas; evaluate the reliability of procedures used for delimitation of morphotypes; and describe their current distribution. Findings determined that morphotypes previously recognized via the linear morphometrics were also supported by geometric morphometrics of the wing shape. In addition, we found an eighth morphotype inhabiting the highlands of Ecuador and Peru. Morphotypes are related into three natural phenotypic groups nominated as Mesoamerican-Caribbean lineage, Andean lineage, and Brazilian lineage. The hypothesis that lineages are not directly related to each other is discussed, supported by their large morphological divergence and endemicity in these three well-defined biogeographic areas. In addition, this hypothesis of the non-monophyly of the Anastrepha fraterculus complex is also supported by evidence from other authors based on molecular studies and the strong reproductive isolation between morphs from different lineages.     

Application of parsimony analysis of endemicity to Mexican gymnosperm distributions: grid-cells, biogeographical provinces and track analysis

Parsimony analysis of endemicity (PAE) was used to analyse the distributional patterns of 124 species of Mexican gymnosperms, using two different sample units: grid-cells and biogeographical provinces. PAE analyses were based on distributional data from herbarium specimens and specialized literature. Two data matrices were constructed for 60 grid-cells of 2° and 14 biogeographical provinces. The analysis of the 2° grid-cell matrix led to 7084 cladograms. The strict consensus cladogram showed several clades equivalent to the results obtained with the biogeographical provinces. Three clades agree with some principal regions of distribution of Mexican pines, previously identified by several authors, located at the northern portion of the Baja California peninsula, the Sierra Madre Occidental, and the Sierra Madre Oriental. These areas represent important centres of species diversity and endemism for Mexican gymnosperms. The analysis of the province matrix led to two most parsimonious cladograms, which only differed in the position of the Sierra Madre Occidental province. The iterative procedure PAE with progressive character elimination was applied to identify generalized tracks, where clades of provinces were considered equivalent to generalized tracks, and each time a cladogram was obtained, species defining its clades were deleted and a new run was undertaken. We found five generalized tracks, mainly located in montane provinces. The distribution patterns of gymnosperms agree with the existence of several Mexican biogeographical provinces, and a different historical biogeography of the Mexican peninsulas from the rest of the country is evident.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 405–417.     

Genetic diversity and ecological distribution ofPhaseolus vulgaris (Fabaceae) in northwestern South America

Our goal was to investigate in more detail wild and cultivated common bean (Phaseolus vulgaris) accessions from northwestern South America (Colombia, Ecuador, and northern Peru) because prior research had shown this region to be the meeting place of the two major gene pools (Middle American and Andean) of common bean. Explorations were conducted in these countries to collect additional materials not represented in germplasm collections. It was possible to identify wild common bean populations in Ecuador and northern Peru, where they had never been described before. In addition, we were able to extend the distribution of wild common bean in Colombia beyond what was known prior to this study. In all areas, the wild common bean habitat had suffered severely from destruction of natural vegetation. In Colombia, wild common beans were found on the Eastern slope of the Andes (in continuation of its distribution in Venezuela), whereas in Ecuador and northern Peru they were found on the western slope of this mountain range. This geographic distribution was correlated with an ecological distribution in relatively dry environments with intermediate temperatures (known as “dry mountain forest”). Isozyme andphaseolin seed protein analyses of the northern Peruvian and Ecuadoran wild populations showed that they were intermediate between the Middle American and Andean gene pools of the species. Phaseolin analyses conducted on landraces of the Upper Magdalena Valley in Colombia showed that Andean domesticates were grown at a higher altitude than Middle American domesticates suggesting that the former are adapted to cooler temperatures. Our observations and results have the following consequences for the understanding and conservation of genetic diversity in common bean and other crops: 1) Our understanding of the distribution of the wild relative of common bean (and other crops) is imperfect and further explorations are needed to more precisely identify and rescue wild ancestral populations; 2) For crops for which the wild ancestor has not yet been identified, it may be worthwhile to conduct additional explorations in conjunction with genetic diversity studies at the molecular level to guide the explorations; 3) Our study shows the benefit for more efficient germplasm conservation which can be derived from the dynamic interplay between field explorations (and other conservation operations) and molecular analyses to determine genetic distances and diversities; 4) The intermediate materials identified in northern Peru and Ecuador may have basic importance to understand the origin of the common bean and an applied role as a bridge between the Middle American and Andean gene pools; and 5) The differential adaptation to temperature of the two major cultivated gene pools may help breeders select genotypes based at least partially on their evolutionary origin.     

A new species of Brachygasterina Macquart from Chile (Diptera: Muscidae)

The genus Brachygasterina Macquart is Neotropical, with six species recorded from Argentina, Chile, Ecuador and Colombia. A new species was found among an extensive unidentified muscid material from South America in the collection of the California Academy of Sciences collection (San Francisco, California, U.S.A.). Brachygasterina maculata, new species, from Santiago, Chile, is here described and illustrated, and its position in the genus Brachygasterina is discussed.     

Distributional patterns of freshwater taxa (fishes, crustaceans and plants) from the Mexican Transition Zone

Aim  To test whether distributional patterns of Neotropical freshwater taxa fit the generalized tracks already postulated for terrestrial groups occurring in the Mexican Transition Zone.
Location  The study units comprised 17 hydrological basins located along the Pacific coast of the Americas from Mexico to Panama, and in the Gulf of Mexico from the Papaloapan to the Grijalva–Usumacinta basin.
Methods  Distributional data for 22 fish species, 34 crab species of the tribe Pseudothelphusini, and 22 strictly freshwater species of angiosperms were analysed. Parsimony analysis of endemicity is based on presence/absence data of these taxa and uses the computer programs Winclada and NONA.
Results  Three generalized tracks were obtained: (1) Mexican North Pacific, (2) Mexican Central Pacific, and (3) Southern Mexico–Guatemala. A node resulted at the intersection of the first two tracks, coinciding with the Neovolcanic Axis in central Mexico.
Main conclusions  Freshwater generalized tracks with an altitudinal distribution below 1000 m, mainly including fishes and angiosperms, are close to the Tropical Mesoamerican generalized track. Generalized tracks above 1000 m, including freshwater crabs, have a stronger affinity with the Mountain Mesoamerican track. The Isthmus of Tehuantepec represents a node for the Neotropical freshwater and terrestrial biota. These results seem to indicate that common geobiotic processes have induced these patterns.     

Passalidae (Coleoptera: Scarabaeoidea) of the Biogeographical Province of Chocó and the West Andean Region of Colombia,with the Description of Two New Species

We present a synopsis of the Passalidae of the Chocó biogeographical province and the western slopes of the Western Andean range of Colombia as a result of field collections, examination of entomological collections, and review of the literature. We record a total of 41 species, provide an identification key, and, for the 39 species for which we were able to examine specimens, include a diagnosis and collecting data. Two new species of Passalus (Pertinax) are described and illustrated. The species of this region compose 42% of the passalid species known for Colombia. The richness of species and the high degree of endemism (34%) indicate the faunistic importance of this area, which is closely related to the fauna of lowland Central America.     

Does the Trans‐mexican Volcanic Belt represent a natural biogeographical unit? An analysis of the distributional patterns of Coleoptera

Aim We analysed the geographical distribution of beetle species of the families Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae from the Trans‐mexican Volcanic Belt (TVB) through a track analysis and a parsimony analysis of endemicity (PAE), in order to test its naturalness and determine its affinities. Location The area analysed corresponds to the TVB, which is a biogeographical province of the Mexican Transition Zone. Methods The panbiogeographical analysis was based on the comparison of the individual tracks of 299 species of Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae (Coleoptera). The TVB was divided into 1^o × 1^o grid cells and we also included in the analysis the remaining Mexican biogeographical provinces. Parsimony analysis of endemicity with progressive character elimination (PAE‐PCE) was applied to classify areas by their shared taxa according to the most parsimonious cladograms. The nested sets of areas were represented as generalized tracks. Results Three generalized tracks were obtained: (1) grid cells 9C, 9D, 10D, 10E, Sierra Madre Oriental, Chiapas, Mexican Gulf and the Sierra Madre del Sur; (2) grid cells 3B, 3C, 4B, 4C, 5C, 6C, 7C, Sierra Madre Occidental, Sierra Madre del Sur, Balsas Basin and the Mexican Pacific Coast, and (3) grid cells 8D, 9C, 9D, 10D, 10E, Yucatán Peninsula, Chiapas, Sierra Madre Oriental and the Mexican Gulf. Main conclusions We conclude that the TVB does not represent a natural biogeographical unit because it shows different relationships with other biogeographical provinces, being clearly transitional between the Nearctic and Neotropical provinces. Some parts of the TVB are related to Neotropical provinces (Chiapas, Mexican Gulf and Mexican Pacific Coast) and others to the remaining provinces of the Mexican Transition Zone (Sierra Madre Oriental, Sierra Madre del Sur, Sierra Madre Occidental and Balsas Basin).     

The emergent macrophyte Montrichardia linifera (Arruda) Schott (Alismatales: Araceae), a rekindled old friend from the Pacific Slope of lower Central America and western Colombia

The genus Montrichardia are among the most remarkable emergent macrophytes in tropical wetlands. It occurs exclusively in the Neotropics and contains two living species, M. linifera (Arruda) Schott and M. arborescens (L.) Schott. Montrichardia linifera has been reported mainly in the Amazon basin (southern Venezuela to Guyana, Brazil, Ecuador and Peru), whereas M. arborescens occurs in Central America (Mexico to Panama), the Lesser Antilles and northern South America. Based on our review of herbarium specimens from Central America and Colombia, as well as field documentation in Panama, we hereby provide the first report of the occurrence of M. linifera in Panama, Central America and western Colombia. Furthermore, this finding represents the first record on the Pacific Slope for this species in the Neotropics. The habitat, ecology, life-form, taxonomic remarks and morphological characteristics of the species are presented, discussed and illustrated. Additionally, a key for the species of the genus Montrichardia is included; we also provide a discussion about the helophyte concept for the genus Montrichardia.     

Do fleas (Insecta: Siphonaptera) parallel their mammal host diversification in the Mexican transition zone?

Aim The Mexican transition zone is a complex area where Neotropical and Nearctic biotic elements overlap. A previous study on mammal species has shown a great diversification in the area. We analyse the diversification of their flea species (Insecta: Siphonaptera), in order to determine if a diversification similar to their mammal host species has occurred. Location The area analysed corresponds to Mexico. Methods The panbiogeographical or track analysis was based on the comparison of the individual tracks of 112 species belonging to 48 genera and eight families of the order Siphonaptera. Generalized tracks were obtained based on the comparison of the individual tracks. Nodes were found in the areas where generalized tracks overlapped. Results Thirty‐four generalized tracks were obtained, distributed within the Mexican transition zone (20), the Nearctic region plus the Mexican transition zone (8), the Nearctic region (4) and the Neotropical region plus the Mexican transition zone (2). In the areas where they intersected, 26 nodes were identified: 23 in the Mexican transition zone and 3 in the Nearctic region. Main conclusions The nodes are concentrated in the Transmexican Volcanic Belt (14), Sierra Madre Oriental (5) and Sierra Madre del Sur (4) provinces of the Mexican transition zone. These results show a significant diversification of the flea taxa, in parallel with the diversification of their mammal hosts.     

Distribution patterns of the genus Pacifigorgia (Octocorallia: Gorgoniidae): track compatibility analysis and parsimony analysis of endemicity

Aim We analysed the distribution patterns of the eastern Pacific octocoral genus Pacifigorgia and deduced its ancestral distribution to determine why Pacifigorgia is absent from the Gulf of Mexico, the Caribbean of central America, and the Antilles. We also examined the current patterns of endemism for Pacifigorgia to look for congruence between hot spots of endemism in the genus and generally recognized areas of endemism for the eastern Pacific. Location The tropical eastern Pacific and western Atlantic, America. Methods We used track compatibility analysis (TCA) and parsimony analysis of endemicity (PAE) to derive ancestral distribution patterns and hot spots of endemism, respectively. Distributional data for Pacifigorgia were gathered from several museum collections and from fieldwork, particularly in the Pacific of Costa Rica and Panama. Results A single generalized track joined the three main continental eastern Pacific biogeographical provinces and the western Atlantic. This track can be included within a larger eastern Atlantic–eastern Pacific transoceanic track that may be the oldest transoceanic track occurring in the region. PAE results designate previously recognized eastern Pacific biogeographical provinces as Pacifigorgia hot spots of endemism. The number of endemic species, which for other taxonomic groups is similar among the eastern Pacific provinces, is higher in the Panamic province for Pacifigorgia. Main conclusions We propose that the absence of Pacifigorgia from the Gulf of Mexico, the Caribbean of central America, and the Antilles is the result of an ancient absence of the genus from these areas rather than the consequence of a major, recent, extinction episode. The Cortez province and the Mexican province appear together as a result of either non‐response to vicariance or dispersal across the Sinaloan Gap. We posit that the Central American Gap acts as a barrier that separates the Panamic province from the northern Cortez–Mexican province.     

Revisions of Pterogastra and Schwackaea (Melastomataceae: Melastomeae)

The closely related neotropical melastomean genera Pterogastra and Schwackaea are revised, the species illustrated, and their distribution mapped. Schwackaea is maintained as a monotypic genus because it is readily distinguished from all other melastomes by its 8-winged capsule. This weedy little plant occurs from Mexico throughout Central America, chiefly on the Pacific slope, to northern Colombia and on Cocos Island and grows in natural or man-made savannas from sealevel to 2000 m altitude. Two species are recognized in Pterogastra and one new combination, P. divaricata spp. glabra , is made. Pterogastra is characterized by distinctly 4- or 5-winged capsules, unlike those of Schwackaea or any other New World melastome. The more widespread species occurs in Colombia, Venezuela, Guyana, Ecuador, and Peru at altitudes between sealevel and 2600 m in natural or disturbed grasslands. The second species is endemic in southwestern Venezuela and is confined to natural savannas at low altitudes.     

Cebus phylogenetic relationships: a preliminary reassessment of the diversity of the untufted capuchin monkeys

The untufted, or gracile, capuchin monkeys are currently classified in four species, Cebus albifrons, C. capucinus, C. olivaceus, and C. kaapori, with all but C. kaapori having numerous described subspecies. The taxonomy is controversial and their geographic distributions are poorly known. Cebus albifrons is unusual in its disjunct distribution, with a western and central Amazonian range, a separate range in the northern Andes in Colombia, and isolated populations in Trinidad and west of the Andes in Ecuador and northern Peru. Here we examine previous morphological and molecular hypotheses of the taxonomy and phylogeny of Cebus. We construct a time-calibrated phylogeny based upon mitochondrial DNA sequences from 50 Cebus samples from across their range. Our data indicate that untufted capuchins underwent a radiation at about 2 Ma, and quickly diversified in both the Andes and the Amazon. We provide a provisional reassessment for the taxonomy of untufted capuchins in the Amazon, the Llanos, the Andes, Trinidad, and Central America, splitting currently paraphyletic taxa into several species, including: at least two Amazonian species (C. yuracus and C. unicolor); a species from the Guiana Shield (most likely the same as Humboldt's C. albifrons); two northern Andean species, C. versicolor, C. cesarae; C. brunneus (with trinitatis a junior synonym) on the Venezuelan coast, and C. adustus in the region of Lake Maracaibo; C. capucinus in northwestern Ecuador and Colombia, and Panama; C. imitator in Central America; C. olivaceus and C. castaneus occupying a large part of the Guiana Shield; and C. kaapori in the eastern Amazon, south of the Rio Amazonas. More intensive and extensive geographic sampling is needed, including that for some subspecies not represented here. Taxa from the southwestern Amazon (yuracus, cuscinus, and unicolor) and the phylogenetic position of Humboldt's Simia albifrons from the Orinoco remain particularly poorly defined.