Urotrema shirleyae n. sp. (Trematoda: Digenea: Urotrematidae) in Norops oxylophus and N. cupreus (Squamata: Iguania: Polychrotidae) from the Area de Conservación Guanacaste, Costa Rica

A new species of Urotrema inhabits Norops oxylophus and Norops cupreus from the Area de Conservación Guanacaste, Costa Rica. The new species is most similar to Urotrema scabridum but differs by having a relatively longer esophagus, at least 10% of the total body length versus 4-8% in U. scabridum; an oral sucker width: ventral sucker width ratio less than 1 : 1 (averaging 1 : 0.76) versus 1 : 1 or greater; an oral sucker width : pharyngeal width ratio less than 1 : 0.5 (averaging 1 : 0.42) versus greater than 1 :0.5; and by having many transversely oriented posttesticular uterine loops versus a few vertically oriented posttesticular uterine loops.     

Tinamutrema canoae n. gen. et n. sp. (Trematoda: Digenea: Strigeiformes: Brachylaimidae) in Crypturellus cinnamomeus (Aves, Passeriformes, Tinamidae) from the Area de Conservación Guanacaste, Costa Rica

We propose Tinamutrema as a new genus for Brachylaima centrodes (Braun, 1901) Dollfus, 1935 and for T. canoae, as a new species inhabiting tinamus in the Area de Conservación Guanacaste, Costa Rica. Specimens from Costa Rica resemble B. centrodes in having an elongate body, pretesticular genital pore and terminal genitalia, intercecal uterine loops occupying all available space between the anterior testis and the intestinal bifurcation, an oral sucker width:pharynx width ratio of approximately 1:0.55, an oral sucker:ventral sucker width ratio of approximately 1:1, and vitelline follicles extending into the forebody closer to the pharynx than to the anterior margin of the ventral sucker and by living in the cloaca. They differ from B. centrodes in having vitelline follicles that do not extend as far anteriorly as those in B. centrodes, which extend anteriorly to the level of the anteriormost extent of the cecal "shoulders," dense tegumental spination as opposed to sparse or no spination, relatively smaller cirrus with fewer spines, longer and more sinous pars prostatica, and forebody averaging 36% of total body length (TBL) as opposed to 42% TBL. Both species differ from other members of the Brachylaimidae in possessing a spinose cirrus and a cirrus sac containing both the cirrus and the pars prostatica. Preliminary phylogenetic assessment suggests that these traits are plesiomorphic, and thus the species are basal to the rest of the Brachylaimidae, whose diagnosis we emend accordingly.     

Bakkeius moragai n. gen. et n. sp. and Pojmanskia riosae n. gen. et n. sp. (Trematoda: Digenea: Brachylaimoidea) in birds from the Area de Conservación Guanacaste, Costa Rica

We describe 2 new species of leucochloridiid-like brachylaimoid digeneans parasitizing a variety of birds in the Area de Conservación Guanacaste, Costa Rica, each of which we assign to a new genus. According to Pojmanska's (Pojmanska, T. 2002a. Superfamily Brachylaimoidea Joyeux & Foley, 1930. In Keys to the Trematoda, D. I. Gibson, A. Jones, and R. A. Bray [eds.]. CAB International and The Natural History Museum, London, U.K., p. 31-36.) key for the Brachylaimoidea, we are unable to place either species in any family. One species most closely resembles members of Leucochloridium by having well-developed suckers, lacking an esophagus, and having cecal shoulders, gonads at the posterior end, and the genital pore at posterior end of body but differs by having symmetrical testes, a posttesticular ovary, and a terminal genital pore; thus, we propose the genus Bakkeius for it. The second new genus resembles members of Michajlovia by having ventral genital pores but differs by having extracecal uterine loops in the forebody, a cirrus sac containing the pars prostatica and seminal vesicle, and gland cells surrounding the genital pore; thus, we propose Pojmanskia for it. These new genera must currently be treated as incertae sedis according to Pojmanska (op. cit.); however, we feel that future phylogenetic analyses will require emendation of the family diagnosis for Leucochloridiidae to include those taxa with terminal and ventral genital pores and with preovarian testes.     

Parapharyngodon duniae n. sp. (Nematoda: Pharyngodonidae) in Phrynohyas venulosa (Anura: Hylidae) from the Area de Conservación Guanacaste, Guanacaste, Costa Rica

Parapharyngodon duniae n. sp. (Nematoda: Pharyngodonidae) in the large intestine of the veined tree frog, Phrynohyas venulosa, from the Area de Conservación Guanacaste in northwestern Costa Rica is described and illustrated. Parapharyngodon duniae n. sp. represents the 34th species assigned to the genus, the 10th species from the Neotropical Realm, and only the third species to parasitize anurans. It is distinguished from the other Neotropical species by having postbulbar ovaries and a prebulbar excretory pore.     

Neohaematotrephus arayae n. sp. (Digenea: Echinostomiformes: Cyclocoelidae) in Jacana spinosa (Aves: Charadriiformes: Jacanidae) from the Area de Conservación Guanacaste, Costa Rica

Specimens of a species of cyclocoelid digenean inhabiting Jacana spinosa from the Area de Conservación Guanacaste, Costa Rica, most closely resemble Haematotrephus facioi (Brenes and Arroyo, 1962) Yamaguti, 1971, in the same host from Aranjuez, Puntarenas Province, Costa Rica, in having confluent vitelline follicles posteriorly, diagnostic of Neohaematotrophus, and in pharynx length, ovary width, and cirrus sac on the sinistral side. The new species is also highly similar in appearance to H. gendrei Dubois, 1959, also inhabiting a jacanid (from West Africa), which has vitelline follicles confluent posteriorly, and extending anteriorly to the intestinal bifurcation and genital pore opening immediately posterior to the anterior margin of the pharynx. Like H. facioi, H. gendrei has a relatively much shorter and broader cirrus sac than does the new species. Examination of the holotype and paratype of H. facioi confirmed that the specimens from Guanacaste differ in having a longer body, a larger ovary and eggs, and smaller testes. They also have the ovary on the sinistral rather than the dextral side of the body, genital pore anterior to the pharynx rather than at or posterior to the level of the posterior margin of the pharynx, longer and thinner cirrus sac, and eggs without eyespotted miracidia. Half the eggs in both specimens of H. facioi have well-developed eyespotted miracidia, whereas the typical condition for cyclocoelids is for virtually all eggs to exhibit eyespotted miracidia. Both H. facioi and H. gendrei are transferred to Neohaematotrophus, along with the new species.     

Paracreptotrema blancoi n. gen., n. sp. (Digenea: Plagiorchiformes: Allocreadiidae) in the Olomina, Priapichthys annectens (Osteichthyes: poeciliidae), from the Area de Conservación Guanacaste, Costa Rica

A new species of allocreadiid digenean is described from Priapichthys annectens (Regan) (Osteichthyes: Poeciliidae) in the Area de Conservación Guanacaste, Costa Rica. A new genus, Paracreptotrema, is proposed to accommodate this species as well as Fellodistomum mendezi Songandares-Bernal, 1955, which was previously described from another poeciliid, Brachyrhaphis episcopi, in Panama. Paracreptotrema differs from all other nominal genera of Allocreadiidae by a combination of its symmetrical testes, restricted vitellaria, and the lack of oral lappets (muscular 'papillae') or other such appendages. Paracreptotrema blancoi n. sp. resembles Creptotrema creptotrema Travassos, Artigas and Pereira, 1928, but differs in lacking ventral oral lappets and in having vitellaria extending posteriorly only to the level of the testes. It can be distinguished from P. mendezi n. comb. in having a relatively larger and more posteriorly placed acetabulum, vitellaria that are more restricted anteriorly, smaller testes, and a uterus that does not extend to the posterior end of the body. The genus seems to be restricted to poeciliids in Central America.     

Wallinia chavarriae n. sp. (Trematoda: Macroderoididae) in Astyanax aeneus (Gunther, 1860) and Bryconamericus scleroparius (Regan, 1908) (Osteichthyes: Characidae) from the Area de Conservación Guanacaste,Costa Rica

Wallinia chavarriae n. sp. is described from the small-bodied characids Astyanax aeneus and Bryconamericus scleroparius in the Area de Conservación Guanacaste, northwestern Costa Rica. The species differs from W. valenciae in possessing an acetabulum that is smaller than the oral sucker and vitelline follicles that are ovoid or rounded rather than elongate and tubular. Detailed comparison between these 2 species is handicapped by the less than satisfactory condition of the type and only museum specimen of W. valenciae. Wallinia chavarriae and W. valenciae belong to a subfamily of trematodes, Walliniinae, that arguably includes Creptotrematina spp., Magnivitellum simplex, and possibly Margotrema. The morphology of walliniines suggests that they are macroderoidids, but a clearer understanding of their classification could be gained from their larval morphology or from molecular systematic studies. The host associations of a monophyletic Walliniinae would indicate diversification within 2 groups of freshwater fishes: the neotropical characids for species of Wallinia, Creptotrematina, and Magnivitellum and the endemic central Mexican goodeids for those of Margotrema. The biogeography and host associations of these parasites provide a system for studies of potential host switching and vicariance, involving the middle-American and neotropical regions.     

Whallwachsia illuminata n. gen., n. sp. (Trematoda: Digenea: Plagiorchiformes: Prosthogonimidae) in the steely-vented hummingbird Amazilia saucerrottei (Aves: Apodiformes: Trochilidae) and the yellow-olive flycatcher Tolmomyias sulphurescens (Aves: Passeriformes: Tyraninidae) from the Area de Conservación Guanacaste, Guanacaste, Costa Rica

A new species of digenean found in the intestines of the steely-vented hummingbird Amazilia saucerrottei and the yellow-olive flycatcher Tolmomyias sulphurescens from the Area de Conservación Guanacaste, Guanacaste, Costa Rica, resembles members of the Prosthogonimidae in having a highly lobate ovary; an elongate cirrus sac containing the cirrus, pars prostatica, and internal seminal vesicle; no external seminal vesicle; 2 fields of extracecal vitelline follicles restricted to the area between the intestinal bifurcation and testes; and uterine loops occupying all available space in the hind body. The new species differs from all other members of the family in having genital pores opening laterally to the cecum, immediately anterior to the acetabular level, and markedly oblique rather than symmetrical testes. Consequently, we propose the new genus Whallwachsia for the species. Preliminary phylogenetic assessment suggests that the species is the sister group of all other prosthogonimids.     

Procyrnea chabaud, 1958 (Nematoda: Habronematoidea: Habronematidae) in birds from the Area de Conservación Guanacaste, Costa Rica, including descriptions of 3 new species

Four species of Procyrnea were collected in birds from the Area de Conservacion Guanacaste, Costa Rica. Procyrnea brevicaudata n. sp. in Crypturellus cinnamomeus resembles P. ficheuri, P. murrayi, P. ameerae, P. dollfusi, and P. aptera in lacking lateral alae but differs from all these species in having 2 longitudinal ridges on the left side of the body, in having a sinistral rather than ventral vulvar opening, and in having dorsally bent rather than straight female tails. Procyrnea mawsonae n. sp., in Buteo magnirostris, is similar to P. strialata in body size and in having 2 transverse striated lateral alae, but differs by having longer and differently shaped spicules, and by lacking a single preanal sessile papilla. Procyrnea mclennanae n. sp., in Heliomaster constantii, is similar to P. strialata (Zhang, 1991) and P. mawsonae n. sp. in having 2 transverse striated lateral alae, but it can be distinguished from P. strialata and P. mawsonae in having 4 rather than 3 small teeth on the interior border of the pseudolabia, in having unequal rather than equal lateral alae, and in having longer spicules. Procyrnea sp., on the basis of a single adult male in Campephilus guatemalensis, resembles P. suraiyae, P. tulostoma, and P. unilateralis in possessing a single and long lateral ala, but can be distinguished from P. suraiyae and P. tulostoma in the length of the left spicule, in the left spicule having a bifid distal end, the right spicule having a rounded distal end rather than both spicules having pointed distal ends, and in having the lateral ala beginning at the lip region instead of posterior to the cervical papillae. It differs from P. uncinipenis in having a spicule ratio of 1:3.5 rather than 1:2.5, in the left spicule having a bifid rather than alate distal end, and in the absence of a single preanal papilla.     

A new species of Petasiger (Digenea: Echinostomiformes: Echinostomatidae) in the brown pelican, Pelecanus occidentalis, (Aves: Pelecaniformes: Pelecanidae), from the Area de Conservación Guanacaste, Costa Rica

A new species of Petasiger inhabits Pelecanus occidentalis, from the Area de Conservación Guanacaste, Costa Rica. The new species most closely resembles Petasiger novemdecim Lutz 1929 and Petasiger caribbensis Nassi, 1980 by having 19 circumoral spines and vitelline follicles confluent between the ventral sucker and gonads. The new species differs from both of these species by having a cirrus sac that is anteroposteriorly elongate and that reaches posteriorly to the midventral sucker, an ovary and Mehlis' gland that overlap the anterior testis dorsally, a uterus that lies dorsal to the ventral sucker, and a dextromedial genital pore. In P. novemdecim and P. caribbensis the cirrus sac is round and does not extend posteriorly to the anterior margin of the ventral sucker, both the ovary and Mehlis' gland are anterior to the anterior testis, the uterus runs lateral to and not dorsal to the ventral sucker, and the genital pore opens medially and sinistromedially, respectively.     

Lytopylus Förster (Hymenoptera, Braconidae, Agathidinae) species from Costa Rica, with an emphasis on specimens reared from caterpillars in Area de Conservación Guanacaste

Twelve species of Costa Rican Lytopylus are treated; these include all species reared from Lepidoptera caterpillars in Area de Conservación Guanacaste, Costa Rica, over 32 years of caterpillar inventory, as well as two species recorded in the literature as occurring in Costa Rica. Ten new species are described, i.e., Lytopylus bradzlotnicki, Lytopylus colleenhitchcockae, Lytopylus gregburtoni, Lytopylus jessicadimauroae, Lytopylus jessiehillae, Lytopylus mingfangi, Lytopylus rebeccashapleyae, Lytopylus robpringlei, Lytopylus sandraberriosae, Lytopylus vaughntani. The following species are transferred to Lytopylus: Metriosoma flavicalcar Enderlein 1920 to Lytopylus flavicalcarcomb. n.; Bassus macadamiae Brice?o and Sharkey 2000 to Lytopylus macadamiaecomb. n.; Metriosoma bicarinatum Enderlein 1920 to Lytopylus bicarinatumcomb. n.; Metriosoma brasiliense Enderlein 1920 to Lytopylus brasiliensecomb. n.; Bassus tayrona Campos 2007 to Lytopylus tayronacomb. n.; Microdus femoratus Cameron 1887 to Lytopylus femoratuscomb. n.; Microdus melanocephalus Cameron 1887 to Lytopylus melanocephaluscomb. n.; Bassus pastranai Blanchard 1952 to Lytopylus pastranaicomb. n.; Agathis nigrobalteata Cameron 1911 to Lytopylus nigrobalteatuscomb. n. Two keys to species of Lytopylus are presented, one interactive and the other static.     

Spider diversity across an elevation gradient in Área de Conservación Guanacaste (ACG), Costa Rica

Throughout the Neotropics, temperature and precipitation change with elevation and these changes affect the assemblage of species at any particular elevation. We documented the diversity of litter-inhabiting spiders, (Arachnida: Araneae) along a Costa Rican elevational gradient as it relates to covarying abiotic factors such as temperature and precipitation. The spiders we collected were principally unidentifiable juveniles, and so we used Barcode Index Numbers (BINs) derived from DNA barcodes as proxies for species-level interim names. We contrasted these taxon-based estimates with phylogenetic measures of alpha- and beta-diversity derived from both the mitochondrial DNA barcode region and a multi-gene phylogeny of spiders and found that neither the abundance nor the species richness of spiders was significantly correlated with elevation, temperature, or precipitation. However, we did find that spider assemblages in the upper elevation cloud forests were phylogenetically clustered, (and this pattern was unrelated to whether the phylogenetic patterns were derived mitochondrially or from a multi-gene analysis). One standard explanation for such a pattern is that harsh abiotic conditions in higher elevation forests have selected for particular spider lineages; however, this remains to be tested fully. The diversity of leaf-litter spider species we uncovered was high and further sampling of spider abundance and diversity across the ACG is likely to yield many new species.     

Urotocus rossittensis (Trematoda: Digenea: Leucochloriidae) in the scarlet-rumped tanager, Ramphocelus passerinii, and common bush tanager, Chlorospingus ophthalmicus (Passeriformes: Thraupidae), from the Area de Conservación Guanacaste, Costa Rica, with taxonomic revision of the genus and revised key to the leuchochloridiid-like Brachylaimoidea

Urotocus rossittensis occurs in the bursa Fabricii of the scarlet-rumped tanager, Ramphocelus passerinii, and the common bush tanager, Chlorospingus ophthalmicus, from the Area de Conservación Guanacaste, Costa Rica. Morphological examination of type material of U. fusiformis and U. kenyensis and Costa Rican specimens suggests that U. fusiformis and U. kenyensis are indistinguishable from U. rossittensis. Confirmed accounts of Urotocus spp. refer to a single adult morphotype whose geographic distribution includes the Palearctic, Africa, Nearctic, and northern Neotropics.     

Primate life history,social dynamics,ecology, and conservation: Contributions from long-term research in Área de Conservación Guanacaste,Costa Rica

Research on non-human primates in the endangered tropical dry forest of Sector Santa Rosa (SSR), Área de Conservación Guanacaste (ACG), was launched in 1983 and is now one of the longest running studies of primates globally. Such continuous study provides a rare opportunity to ask questions that are only answerable through decades-long monitoring of these long-lived monkeys. In turn, the mounting data generated by long-term study, including knowledge of lifetime reproductive success, familial relatedness, comprehensive behavioral and dietary repertoires, and patterns of inter- and intra-annual variation in forest productivity, provide diverse opportunities to researchers, and facilitate studies that are of shorter duration. Here, we review some of the contributions of our longitudinal research on white-faced capuchins and Geoffroy's spider monkeys, together with newer studies on mantled howler monkeys. We begin by synthesizing findings from our research on demography, dispersal, social relationships, and reproduction. These life history and social traits interact with their foraging and sensory ecology, which we review next. We end by highlighting how the longitudinal study of primates in Sector Santa Rosa has made direct and indirect contributions to the conservation of the critically endangered dry forest biome and its inhabitants, as well as to education, community, and forest restoration initiatives. In particular, we focus our review on how long-term research is uniquely positioned to make key contributions spanning different topical areas.     

Integrative taxonomy of New World Euplectrus Westwood (Hymenoptera,Eulophidae), with focus on 55 new species from Area de Conservación Guanacaste,northwestern Costa Rica

90 species of Euplectrus are treated: 55 newly described, all from Area de Conservación Guanacaste (ACG), and 35 previously described species, of which 20 occur in ACG. Three of the previously described species (Euplectrus brasiliensis Ashmead, Euplectrus hircinus (Say), Euplectrus ronnai (Brèthes)) have unknown status, owing to missing or severely damaged type material. The new species, all authored by C. Hansson, are: Euplectrus alejandrovalerioi, Euplectrus alexsmithi, Euplectrus alvarowillei, Euplectrus andybennetti, Euplectrus andydeansi, Euplectrus annettewalkerae, Euplectrus billbrowni, Euplectrus bobwhartoni, Euplectrus carlosarmientoi, Euplectrus carlrettenmeyeri, Euplectrus charlesmicheneri, Euplectrus charlesporteri, Euplectrus chrisdarlingi, Euplectrus chrisgrinteri, Euplectrus corriemoreauae, Euplectrus daveroubiki, Euplectrus davesmithi, Euplectrus davidwahli, Euplectrus dianariasae, Euplectrus donquickei, Euplectrus eowilsoni, Euplectrus garygibsoni, Euplectrus gavinbroadi, Euplectrus gerarddelvarei, Euplectrus henrytownesi, Euplectrus howelldalyi, Euplectrus hugokonsi, Euplectrus iangauldi, Euplectrus jacklonginoi, Euplectrus jesusugaldei, Euplectrus jimwhitfieldi, Euplectrus jjrodriguezae, Euplectrus johnheratyi, Euplectrus johnlasallei, Euplectrus johnnoyesi, Euplectrus josefernandezi, Euplectrus lubomirmasneri, Euplectrus markshawi, Euplectrus mikegatesi, Euplectrus mikeschauffi, Euplectrus mikesharkeyi, Euplectrus ninazitaniae, Euplectrus pammitchellae, Euplectrus paulhansoni, Euplectrus paulheberti, Euplectrus paulhurdi, Euplectrus philwardi, Euplectrus robbinthorpi, Euplectrus ronaldzunigai, Euplectrus roysnellingi, Euplectrus scottshawi, Euplectrus sondrawardae, Euplectrus sydneycameronae, Euplectrus victoriapookae, Euplectrus wonyoungchoi. The species are described or redescribed, and thoroughly and uniformly illustrated, and included in two identification keys, one for females and one for males. Lectotypes are designated for eight species: Euplectrus catocalae Howard (♂), Euplectrus junctus Gahan (♀), Euplectrus leucotrophis Howard (♂), Euplectrus marginatus Ashmead (♀), Euplectrus pachyscaphus Girault (♀), Euplectrus platyhypenae Howard (♂), Euplectrus semimarginatus Girault (♀), Heteroscapus ronnai Brèthes (♂). One synonym is established: Euplectrus walteri Schauff is a junior synonym of Euplectrus testaceipes (Cameron). Brief image notes and host records are provided on the natural history of the wasps as well as the details of their morphology. Hosts are known for 74 Euplectrus species.     

Ichthyoplankton from the pier area in Limón, Costa Rica

Four sampling stations were set 200-500 m off Limon Port, Costa Rica, at an average depth of 20 m. From October 1996 to May 1997 horizontal subsuperficial trawls were done for 12 minutes at a speed of about 2 Km/h, with a 1,000 microns plancton net. A total of 28 samples were processed and 104 physical-chemistry parameter measurements were taken. Average salinity was 30.1 +/- 3.7 and dissolved oxygen 6.9 +/- 0.6 mg l-1 reflecting good aeration throughout the sampling period. This suggests good mixture and a highly dynamic hydrography. Temperature showed no drastic variations (28.0 +/- 1.7 degrees C), possibly because of the constant mixing with shallow water. The highest larval counts were for November and early January and include families common to reefs and estuaries (Balistidae, Lutjanidae) and to coastal areas (Centropomidae, Gerreidae, Haemulidae, Carangidae, Engraulidae, Hemiramphidae, and representative Pleuronectiformes) existing in a common area.     

Ultrastructural description of Euglena pailasensis (Euglenozoa) from Rincón de la Vieja volcano, Guanacaste, Costa Rica

The euglenoids are unicellular eukaryotic flagellates living in a diversity of soils and aquatic environments and ecosystems. This study describes the ultrastructure of an euglenoid isolated from the surface of a boiling mud pool with temperatures ranging from 38 to 98 degrees C and pH 2 - 4. The hot mud pool is located in Area de Pailas de Barro, Las Pailas, Rincón de la Vieja Volcano, Guanacaste, Costa Rica. The morphological characterization of the Euglena pailasensis was performed by SEM and TEM. It was determined that, although the euglenoid was obtained from an extreme volcanic environment, the general morphology corresponds to that of a typical member of Euglena of 30-45 microm long and 8-10 microm wide, with membrane, pellicle, chloroplasts, mitochondria, nucleus, pigments and other cytoplasmic organelles. E. pailasensis is delimited by a membrane and by 40 to 90 pellicle strips. It was observed up to 5 elongated chloroplasts per cell. The chloroplast contains several osmiophilic globules and a pyrenoid penetrated by few thylakoid pairs. The nutritious material is reserved in numerous small paramylon grains located at the center of the cell, mitocondria are characterized by the presence of crests in radial disposition toward the interior of the lumen. It was also observed around the external surface "pili" like filaments originating from the pellicle strips. There is no evidence for the presence of flagella in the ampulla (reservoir/canal area), a fact confirmed by negative staining, and a difference regarding other species of Euglena. The observed ultrastructural characteristics are not sufficient to explain the adaptation of this species to acid and hot environments.     

Reproductive Seasonality in Female Capuchins (<Emphasis Type="Italic">Cebus capucinus</Emphasis>) in Santa Rosa (Area de Conservación Guanacaste), Costa Rica

The income-capital breeding model was developed to explain birth seasonality and reproductive strategies in female animals in relation to the abundance of food energy in the environment. An income breeder uses currently available energy and acts so as to maximize either maternal survival or weanling survival, depending on the relationship between timing of births and abundance of food energy. A capital breeder stores energy reserves for future reproductive use. Here we examined energetic influences on reproductive seasonality in a population of female white-faced capuchins (Cebus capucinus) living in a seasonal dry forest in Costa Rica. Our objectives were to determine: 1) the degree of fruiting seasonality in capuchin food trees and 2) the temporal relationship between capuchin births/conceptions and fruit abundance. Our sample included 25 yr of birth data (N = 100 births), 4 yr of capuchin fruit tree phenology data, and 18 mo of ovarian hormone data, which we used to calculate gestation lengths and estimate conception dates. Using circular statistics, we found that the mean peak in fruit abundance occurs in June, and that this population of capuchins reproduces seasonally, with 44% of births occurring within a 3-mo period (May to July, mean month = May). We propose that white-faced capuchins can be generally classified as income breeders that maximize maternal survival instead of weanling survival and that they time infant births such that the most energy expensive period of reproduction, mid-to-late lactation, occurs during the mean peak in fruit abundance.