Occurrence and conservation of the Vulnerable titi monkey Callicebus melanochir in fragmented landscapes of the Atlantic Forest hotspot

Tropical forest hotspots have a high diversity of species but have lost > 70% of their original vegetation cover and are characterized by a multitude of small and isolated fragments. Paradoxically, conservation actions in these areas are still mainly focused on protection of large tracts of forests, a strategy now infeasible because of the small area of forest remnants. Here we use the Vulnerable black-handed titi monkey Callicebus melanochir as a model to study the effects of habitat loss, fragmentation and degradation on arboreal mammals and to provide insights for science-driven conservation in fragmented landscapes in tropical forest hotspots. We surveyed 38 Atlantic Forest fragments in Bahia State, Brazil and assessed the effects of patch area, quality and visibility, and landscape connectivity on the occurrence of our model species. Patch area was the single best model explaining species occurrence. Nonetheless, patch quality and visibility, and landscape connectivity, positively affect occurrence. In addition to patch area, patch quality, patch visibility and landscape connectivity are useful for predicting the occurrence of arboreal mammals in the fragments of tropical forest hotspots. We encourage the assessment of habitat quality (based on remotely sensed vegetation indices) and habitat visibility (based on digital elevation models) to improve discoverability of arboreal mammal populations and selection of fragments for conservation purposes across fragmented landscapes of tropical forest hotspots. Large remnants of tropical forest hotspots are scarce and therefore we require baseline data to support conservation actions and management in small forest fragments.

Plecturocebus caquetensis (Primates: Pitheciidae)

Plecturocebus caquetensis (Defler, Bueno, and García, 2010) is a Neotropical primate commonly called the Caquetá titi monkey. It is small-sized with long, soft pelage of mixed coloration including grayish and buffy brown to agouti tones. It lacks the blackish or whitish band that is present on the forehead of closely related species. The tail is agouti-colored and slightly banded at its base. Endemic to the Amazonian region of Colombia with a distribution in areas near the eastern slopes of the Eastern and Central Cordillera of the Andes, P. caquetensis is confirmed in 104 localities in the departments of Cauca and Caquetá in Colombia. P. caquetensis is considered “Critically Endangered” (CR) by the International Union for Conservation of Nature and Natural Resources.

Marcgrave's red-tailed monkey: the earliest European depiction of a titi monkey

Among the approximately 40 species of mammals described in Historia naturalis Brasiliae by Willem Piso and Georg Marcgrave, the identity of the monkey “cagui major” has been one of the most controversial. Authors have identified Marcgrave's “cagui major” as a tamarin, a saki monkey, a squirrel monkey, a titi monkey and even as an Old-World monkey. Based on a watercolour, probably related to the original illustration that served as basis for the “cagui major” woodcut, we confirm that it depicts a titi monkey ( Callicebus). By comparing the pelage characteristics shown in the drawing and some measurements and pelage characteristics described in Historia naturalis Brasiliae, we confirm that the species depicted was Callicebus melanochir that occurs today in southern Bahia and northeastern Minas Gerais states, outside the range of the Dutch possessions in Brazil.

Titi monkey neophobia and visual abilities allow for fast responses to novel stimuli

The Snake Detection Theory implicates constricting snakes in the origin of primates, and venomous snakes for differences between catarrhine and platyrrhine primate visual systems. Although many studies using different methods have found very rapid snake detection in catarrhines, including humans, to date no studies have examined how quickly platyrrhine primates can detect snakes. We therefore tested in captive coppery titi monkeys (Plecturocebus cupreus) the latency to detect a small portion of visible snake skin. Because titi monkeys are neophobic, we designed a crossover experiment to compare their latency to look and their duration of looking at a snake skin and synthetic feather of two lengths (2.5 cm and uncovered). To test our predictions that the latency to look would be shorter and the duration of looking would be longer for the snake skin, we used survival/event time models for latency to look and negative binomial mixed models for duration of looking. While titi monkeys looked more quickly and for longer at both the snake skin and feather compared to a control, they also looked more quickly and for longer at larger compared to smaller stimuli. This suggests titi monkeys’ neophobia may augment their visual abilities to help them avoid dangerous stimuli.

Mammals in atlantic forest remnants of Barbacena, Minas Gerais

Habitat loss and fragmentation are the main causes of biodiversity decline, since changes in environmental and ecological conditions directly affect species richness, abundance, and distribution. This study aimed to identify medium- and large-sized mammals occurring in three Atlantic Forest remnants located in the Barbacena campus of the Federal Institute of Southeast Minas Gerais (IFSudesteMG). The species were recorded in track plots and through active search for direct and indirect signs. 16 species distributed in six orders and 14 families were identified, including some vulnerable and threatened species such as Lycalopex vetulus (meadow fox), Lontra longicaudis (otter), and Callicebus nigrifrons (black-fronted titi monkey). Canis familiaris (domestic dog) and Didelphis sp. (opossum) were the species most frequently observed in the track plots. The largest fragment had the greatest species richness, with 15 species, or 93.75% of the total. The number of species shared among the three sampled areas was 31.2%. The similarities identified between the fragments indicate the need for higher connectivity among them, through the creation of ecological corridors to allow the movement and, consequently, gene flux among the populations, favoring the maintenance of important ecosystem services in the region. Although small, the study area plays a major role in mammal conservation in the region, preserving species from the Cerrado and the Atlantic Forest domains. To reduce potential impacts on the local fauna, management and conservation efforts should be put forward.

Oxytocin receptor binding in the titi monkey hippocampal formation is associated with parental status and partner affiliation

Social cognition is facilitated by oxytocin receptors (OXTR) in the hippocampus, a brain region that changes dynamically with pregnancy, parturition, and parenting experience. We investigated the impact of parenthood on hippocampal OXTR in male and female titi monkeys, a pair-bonding primate species that exhibits biparental care of offspring. We hypothesized that in postmortem brain tissue, OXTR binding in the hippocampal formation would differ between parents and non-parents, and that OXTR density would correlate with frequencies of observed parenting and affiliative behaviors between partners. Subjects were 10 adult titi monkeys. OXTR binding in the hippocampus (CA1, CA2/3, CA4, dentate gyrus, subiculum) and presubiculum layers (PSB1, PSB3) was determined using receptor autoradiography. The average frequency of partner affiliation (Proximity, Contact, and Tail Twining) and infant carrying were determined from longitudinal observations (5–6 per day). Analyses showed that parents exhibited higher OXTR binding than non-parents in PSB1 (t(8) = − 2.33, p = 0.048), and that OXTR binding in the total presubiculm correlated negatively with Proximity (r = − 0.88) and Contact (r = − 0.91), but not Tail Twining or infant carrying. These results suggest that OXTR binding in the presubiculum supports pair bonding and parenting behavior, potentially by mediating changes in hippocampal plasticity.

Epidemiological and molecular characterization of a novel adenovirus of squirrel monkeys after fatal infection during immunosuppression

Adenoviruses are a frequent cause of acute upper respiratory tract infections that can also cause disseminated disease in immunosuppressed patients. We identified a novel adenovirus, squirrel monkey adenovirus 1 (SqMAdV-1), as the cause of fatal infection in an immunocompromised squirrel monkey (Saimiri boliviensis) at the Keeling Center for Comparative Medicine and Research (KCCMR). Sequencing of SqMAdV-1 revealed that it is most closely related (80.4 % pairwise nucleotide identity) to the titi monkey (Plecturocebus cupreus) adenovirus (TMAdV). Although identified in the titi monkey, TMAdV is highly lethal in these monkeys, and they are not thought to be the natural host. While SqMAdV-1 is similar to other primate adenoviruses in size and genomic characteristics, a nucleotide polymorphism at the expected stop codon of the DNA polymerase gene results in a 126 amino acid extension at the carboxy terminus, a feature not previously observed among other primate adenoviruses. PCR testing and partial sequencing of 95 archived faecal samples from other squirrel monkeys (Saimiri boliviensis and Saimiri sciureus) housed at the KCCMR revealed the presence of three distinct, and apparently endemic species of adenoviruses. A grouping of ten squirrel monkey adenovirus variants has high similarity to SqMAdV-1. A single adenovirus variant (designated SqMAdV-3), detected in five monkeys, has similarity to tufted capuchin (Sapajus apella) adenoviruses. The largest group of adenovirus variants detected (designated SqMAdV-2.0–2.16) has very high similarity (93–99 %) to the TMAdV, suggesting that squirrel monkeys may be the natural host of the TMAdV.