Loris Tardigradus Research Articles

Phylogenetic relationship among slender loris species (Primates, Lorisidae: Loris) in Sri Lanka based on mtDNA CO1 barcoding

There are 2 species of slender lorises found in Sri Lanka: the red slender loris, Loris tardigradus (Linnaeus, 1758), endemic to the wet zone and montane areas, and the grey slender loris, Loris lydekkerianus (Cabrera, 1908), which is widespread. In addition, currently there are 2 subspecies recognized for each of these 2 slender loris species of Sri Lanka. Yet their taxonomy, evolutionary history, and biogeography are still poorly understood, and there are some preliminary data suggesting the presence of other subspecies. In this study, we have analysed the partial mitochondrial cytochrome oxidase I gene sequence of 21 Loris specimens collected from 7 different regions in Sri Lanka. The phylogenetic tree reconstructed based on the neighbour joining method and Bayesian approach revealed 2 clades with high branch supports (>60%), consistent with the 2 slender loris species. Moreover, the samples within the Loris lydekkerianus clade were divided into 3 taxa and the samples within the Loris tardigradus clade were divided into 4 taxa, all consistent with the 7 sampling zones. The results of the study have provided the first DNA barcoding analysis on slender lorises in Sri Lanka to resolve phylogenetic relationships. Further studies on Loris are necessary for decoding their taxonomic issues in Sri Lanka.

Neonatal Ectotympanic Bone Variation among Lorisiforms and Tarsiers

Ectotympanic bone morphology is a classic characteristic used to differentiate primates and identify fossil affinities, often depicted as either a ring or tube falling along strict phylogenetic lines. Though ectotympanic bone morphology has been frequently cited in academic literature, the way in which this bone lengthens within and across taxa is still not well understood. The lorisiform ectotympanic bone is often characterized as ring‐like and fused to a slightly expanded petrosal bulla, however some authors have suggested that the degree to which the ectotympanic bone contributes to the external auditory meatus may vary within lorisiforms. The ectotympanic of tarsiers is often depicted as slightly elongate, though not as long as catarrhine primates. It is possible, and likely, that the lorisiform ear canal is longer than the lemuriforms though not as long as tarsiers. However, the degree to which the ectotympanic bone contributes to the ear canal has been a subject of some debate. Thus, can ontogeny resolve the questions surrounding the lorisiform and tarsier ectotympanic bones? Across lorisiforms, is the external auditory meatus derived from the petrosal bone, ectotympanic bone, or some combination of the two at birth?To address these questions, three genera of neonatal lorisiforms (Galago senegalensis, Nycticebus pygmaeus, and Loris tardigradus) and one species of tarsier (Tarsius syrichta) were qualitatively analyzed. It was found that in all three lorisiform species, the ectotympanic ring is formed by birth. The elongation of the ectotympanic bone in lorisiforms occurs almost immediately postnatally. The lorisiform and tarsier ectotympanic bones extend laterally as simple tubes, without forming the tubercles that are observed at intermediate stages in catarrhine species. The precise bony makeup of the lorisiform external auditory meatus varies among the genera studied. At birth among Loris and Nycticebus, the ear canal is already elongated but likely incorporates contributions from structures derived from the squamosal and petrous namely the post‐glenoid tubercle and the auditory bulla. The tarsier ectotympanic bone closely resembles the Galago at birth, and we suggest that the tarsier cranial proportions may be an underlying factor in the ultimate lengthening of the bone in this taxon.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Sources of morbidity in lorises and pottos in North American zoos: A retrospective review, 1980-2010.

Delineating patterns of morbidity can reveal management practices in need of reassessment to improve individual welfare, as well as population health and sustainability. We reviewed medical records from 38 North American zoological institutions for 276 slender lorises, slow lorises, and pottos born between January 1, 1980 and December 31, 2010. This sample included animals identified as 116 Nycticebus pygmaeus, 84 N. coucang, 48 Loris tardigradus tardigradus, 6 L.t. nordicus (now classified as L. lydekkerianus nordicus), and 22 Perodicticus potto. Taxonomy for lorises and pottos is developing, and two of these populations (N. coucang and P. potto) likely included hybrids and/or multiple species. Our focus was to examine trends based on species and age. Across all species, whole body disease events, abnormalities of bloodwork, and dental diseases were the most common sources of morbidity. Other major sources of morbidity varied by species and included trauma, respiratory disease, and ocular disease. A recent upsurge in research has informed feeding practices for slow lorises living in human care, and a similar, evidence-based approach is needed to improve diets for other species. Given the prevalence of trauma in this sample, social needs and reproductive management practices are also important areas for further investigation. Species-level health trends reveal risk factors for individual welfare that can guide husbandry practices in zoos, as well as in sanctuaries caring for the influx of lorises and pottos rescued from the growing wildlife trade.

Functional Morphology of Mimetic Musculature in Primates: How Social Variables and Body Size Stack up to Phylogeny.

Mammalian skeletal muscle is influenced by the functional demands placed upon it. Functional morphology of facial expression musculature, or mimetic musculature, is largely unknown. Recently, primate mimetic musculature has been shown to respond to demands associated with social factors. Body size has also been demonstrated to affect many aspects of primate functional morphology and evolutionary morphology. The present study was designed to further examine the role of social variables and body size in influencing the morphology of primate mimetic musculature using a broad phylogenetic range of primates, primates with varying body sizes, and those that exploit differing time of day activity cycles and social group sizes. Gross data on mimetic musculature morphology were gathered from tarsiers (Tarsius bancanus), slender lorises (Loris tardigradus), ring-tailed lemurs (Lemur catta), crowned lemurs (Eulemur coronatus), black lemurs (E. macaco), owl monkeys (Aotus trivirgatus), and howler monkeys (Alouatta caraya) and compared to previous results from chimpanzees (Pan troglodytes), gibbons and siamangs (hylobatids), rhesus macaques (Macaca mulatta), Sulawesi macaques (M. nigra), common marmosets (Callithrix jacchus), and greater bushbabies (Otolemur spp.). Mimetic muscle presence/absence was observed and recorded. Results revealed that phylogenetic position determines the overall mimetic muscle groundplan, with anthropoids having a high number of muscles in the superciliary and midface regions, strepsirrhines having a high number of muscles in the external ear region, and tarsiers displaying an intermediate condition. Within these broad taxonomic categories body size had an effect on mimetic musculature, while time of day activity and social group size had smaller effects. Anat Rec, 301:202-215, 2018. © 2018 Wiley Periodicals, Inc.

Selecting a Conservation Surrogate Species for Small Fragmented Habitats Using Ecological Niche Modelling.

Simple SummaryLarge “charismatic” animals (with widespread popular appeal) are often used as flagship species to raise awareness for conservation. Deforestation and forest fragmentation are among the main threats to biodiversity, and in many places such species are disappearing. In this paper we aim to find a suitable species among the less charismatic animal species left in the fragmented forests of South-western Sri Lanka. We selected ten candidates, using a questionnaire survey along with computer modelling of their distributions. The red slender loris and the fishing cat came out as finalists as they were both appealing to local people, and fulfilled selected ecological criteria.Flagship species are traditionally large, charismatic animals used to rally conservation efforts. Accepted flagship definitions suggest they need only fulfil a strategic role, unlike umbrella species that are used to shelter cohabitant taxa. The criteria used to select both flagship and umbrella species may not stand up in the face of dramatic forest loss, where remaining fragments may only contain species that do not suit either set of criteria. The Cinderella species concept covers aesthetically pleasing and overlooked species that fulfil the criteria of flagships or umbrellas. Such species are also more likely to occur in fragmented habitats. We tested Cinderella criteria on mammals in the fragmented forests of the Sri Lankan Wet Zone. We selected taxa that fulfilled both strategic and ecological roles. We created a shortlist of ten species, and from a survey of local perceptions highlighted two finalists. We tested these for umbrella characteristics against the original shortlist, utilizing Maximum Entropy (MaxEnt) modelling, and analysed distribution overlap using ArcGIS. The criteria highlighted Loris tardigradus tardigradus and Prionailurus viverrinus as finalists, with the former having highest flagship potential. We suggest Cinderella species can be effective conservation surrogates especially in habitats where traditional flagship species have been extirpated.

Metabolic activity and energy expenditure in primates

Hibernation is not a physiologic function that is normally associated with primates, but can perhaps be considered an extreme of the spectrum of metabolic activity and energy expenditure. The perspective that energy expenditure is directly proportional to physical activity may apply across the zoologic record, but has been questioned for primates [1]. Pontzer [1] stated that primates use half the energy of other mammals. Among the factors affecting energy demands, body mass/size is the major overriding determinant of thereutral resting metabolic rate [1]. This holds across mammalian phylogeny, with notable exception of marsupials, edentates, and among primates, strepsirrhines [2,3]. Hypometabolism among Strepsirrhini is greatest for Eulemur fulvus and Lemur catta (69% reduction in basal metabolic rate), Nycticebus coucang (63%), Varecia varecia (70%), Propithecus verrauxi (87%) and least for Galago elegantulus (1.5%), with Lepilemur ruficaudatus, Loris tardigradus, Otolemur crossicaudatus and garnetti and Periodictus potto intermediately reduced at 45% [4]. This contrasts with Haplorhini which is a highly variable suborder. Most approximate anticipated (for their mass) metabolic rate, with the exception of hypometabolism in Aotus triviragautus, Cebuella and Tarsius syrichta. This contrasts with increased basal metabolism in Cercopithicus mitus, Erythrocebus and Macacca fasculatus and fuscata, Saguinus geoffroyi, Papio cynocephalus and Calithix geoffroyi. It is intriguing that the 20% increase in basal metabolic rate in Calithix geoffroyi contrasts with a 30% decrease in C. jacchus decreased 30%. Similarly, basal metabolic rate was as anticipated for weight in Macacca mulatta and Papio papio, in contrast to M. fasculatus, M. fuscata, and Papio cynocephalus.

A retrospective review of mortality in lorises and pottos in North American zoos, 1980-2010

Patterns of mortality in captive animals can reveal potentially problematic care prac- tices or other risk factors that may negatively impact animal health and population sustainability. We reviewed death records (necropsy and/or histopathology reports) for 367 lorises and pottos born between 1980 and 2010 that were housed in 33 North American zoos and related facilities. Our sample included 20 Loris tardigradus nordicus, 72 L. t. tardigradus, 109 Nycticebus coucang, 133 N. pygmaeus, and 33 Perodicticus potto. In all 5 groups, neonates (animals 20% of animals showed signs of disease included the cardiovascular and hemolymphatic, endocrine and metabolic, gastrointestinal, and immunologic systems. Our results indicate that reducing neonatal mortality is a major priority for sustaining these species in captivity, and common practices for managing groups during the peri- natal period should be carefully scrutinized. Other areas in need of further investigation are envi- ronmental contributions to neoplastic and infectious disease, and dietary contributions to chronic degenerative conditions.

Functional and evolutionary aspects of axial stability in euarchontans and other mammals

The presence of a stable thoracolumbar region, found in many arboreal mammals, is considered advantageous for bridging and cantilevering between discontinuous branches. However, no study has directly explored the link between osteological features cited as enhancing axial stability and the frequency of cantilevering and bridging behaviors in a terminal branch environment. To fill this gap, we collected metric data on costal and vertebral morphology of primate and nonprimate mammals known to cantilever and bridge frequently and those that do not. We also quantified the frequency and duration of cantilevering and bridging behaviors using experimental setups for species that have been reported to show differences in use of small branches and back anatomy (Caluromys philander, Loris tardigradus, Monodelphis domestica, and Cheirogaleus medius). Phylogenetically corrected principal component analysis reveals that taxa employing frequent bridging and cantilevering (C. philander and lorises) also exhibit reduced intervertebral and intercostal spaces, which can serve to increase thoracolumbar stability, when compared to closely related species (M. domestica and C. medius). We observed C. philander cantilevering and bridging significantly more often than M. domestica, which never cantilevered or crossed any arboreal gaps. Although no difference in the frequency of cantilevering was observed between L. tardigradus and C. medius, the duration of cantilevering bouts was significantly greater in L. tardigradus. These data suggest that osteological features promoting axial rigidity may be part of a morpho-behavioral complex that increases stability in mammals moving and foraging in a terminal branch environment.

Current distribution and abundance of slender lorises (Loris tardigradus and L. Iydekkerianus) in Sri Lanka

Two species of slender lorises are currently recognized in Sri Lanka. They are Sri Lanka red slenderloris (Loris tardigradusj and Grey slender loris (L. lydekkerianus i, with four currently recognizedsub-species; viz. Western red slender loris (L. t. tardigradus), Montane slender loris (L. t.nycticeboidesi, Northern grey slender loris (L. 1.nordicusi, and Highland slender loris (L. 1.grandis).The objective of this survey was to map the distribution and estimate the abundance of lorises in SriLanka. The study was initiated in 2002 and continues to date. Thus far forty-five sites across all ofthe ecological zones have been surveyed covering approximately 400 krn-. In six of these sites, loriseswere not recorded. Of the other 39 sites, 223 sightings of slender loris (L. t. tardigradus (n = 86), L.t. nycticeboides (n = 3), L. 1. nordicus (n = 122), and L. l. grandis (n = 12). Abundance estimates, 'base on sightings of animals krn', were: L. t. tardigradus (0.5-8), L. t. nycticeboides (0.03), L. I.nordicus (0.7-13). and L. 1. grandis (0.3-4) were recorded. The abundance of lorises varied indifferent habitat types with the highest abundance oflorises occurring in the dry zone monsoon forests.The least abundance of lorises was recorded in the cloud forest.

An ethnoprimatological approach to assessing levels of tolerance between human and commensal non-human primates in Sri Lanka.

Human and non-human primates increasingly are forced to live commensally, and understanding the human-nonhuman interconnections are paramount in understanding tolerance and conflict. In our study area, the heavily deforested parts of southern Sri Lanka humans and primates live side by side and prevalent religious tenets encourage a peaceful co-existence. We quantify the attitudes of rural communities towards three resident primate species (red slender loris, purple-faced langur, toque macaque) and wildlife conservation through semi-structured interviews with 301 people. Presence of the three primates on people' s land or farms was not related to the distance to the nearest forest but for langurs the incidence of crop-raiding was negatively related to distance to the forest. Despite Buddhist' s beliefs about 10% of interviewees indicated having killed primates (in the past) but levels of killing was not related to awareness of protective status of the primates. Overall however positive attitudes towards primates prevailed, without noticeable influence of sex, education or employment type. There was overwhelming support for forest protection measures - not because of the primates but mainly for water preservation and for ensuring a steady timber supply. We found that despite high levels of deforestation, and an increase of encroachment of humans into primate habitats, attitudes has led only to a limited increased level of tension between humans and primates.

Dental disease in slender lorises (Loris tardigradus)

Necropsies were performed in 25 slender lorises (Loris tardigradus) from a colony at Bochum University. In seven adult individuals, teeth were missing, loose, or severely affected by dental calculus. In one of these cases, a severe periodontal disease was seen without abscess formation. In another four lorises purulent/gangrenous inflammation was found next to the teeth either in the maxillary or the mandibular region.

A Survey of Husbandry Practices for Lorisid Primates in North American Zoos and Related Facilities

Zoos and related facilities in North America currently manage five species in the primate family Lorisidae: the greater (Nycticebus coucang), Bengal (N. bengalensis) and pygmy (N. pygmaeus) slow lorises, red slender loris (Loris tardigradus), and potto (Perodicticus potto). We used an online survey to describe institutional housing and husbandry practices for these species and assess the extent to which practices are consistent with established guidelines. Our results show that most captive lorisids are housed solitarily or in pairs. Most individuals occupy a single exhibit space in a building dedicated to nocturnal animals. Facilities are commonly meeting recommendations for abiotic exhibit design and are providing animals with an enriched environment. However, pottos and slender lorises currently occupy exhibit spaces smaller than the recommended minimum, and the impact of cleaning protocols on olfactory communication should be critically evaluated. Few facilities are taking advantage of the benefits of positive reinforcement training for promoting animal welfare. Research is greatly needed on the effects of exhibit lighting on behavior, health, and reproduction; and to determine how best to manage the social needs of lorisids with naturally dispersed social structures. Although captive populations of slender lorises, pottos, and slow lorises are declining, we suggest that improved husbandry knowledge has the potential to positively influence population sustainability and to enhance future efforts to manage the growing pygmy loris population.

GALLSTONES IN SLENDER LORISES (LORIS TARDIGRADUS)

A total of 32 slender lorises (Loris tardigradus) kept in captivity were investigated postmortem. In five adult lorises (4 females, 1 male), the gallbladder contained either one gallstone or multiple gallstones. Except for one 5-yr-old female, the affected individuals were between 11 and 13 yr of age. All of the gallstones consisted of 100% cholesterol. Besides other predisposing factors such as species, sex, increasing age, and diabetes mellitus, nutrition may play a major role in the occurrence of these gallstones.

Growth and the development of sexual size dimorphism in lorises and galagos

Three fundamental ontogenetic pathways lead to the development of size differences between males and females. Males and females may grow at the same rate for different durations (bimaturism), grow for the same duration at different rates, or grow at a mix of rate and duration differences. While patterns of growth and the development of adult body size are well established for many haplorhines, the extent to which rate and duration differences affect strepsirrhine growth trajectories remains unclear. Here, we present iterative piecewise regression models that describe the ontogeny of adult body mass for males and females of five lorisoid species (i.e., lorises and galagos) from the Duke Lemur Center. We test the hypotheses that, like most haplorhines, sexual size dimorphism (SSD) is a result of bimaturism, and males and females of monomorphic species grow at the same rate for a similar duration. We confirm that the galagos in this sample (Galago moholi and Otolemur garnettii) show significant SSD that is achieved through bimaturism. Unlike monomorphic lemurids, the lorises in this sample show a diversity of ontogenetic patterns. Loris tardigradus does follow a lemur-like trajectory to monomorphism but Nycticebuscoucang and Nycticebus pygmaeus achieve larger adult female body sizes through a mixture of rate and duration differences. We show that contrary to previous assumptions, there are patterns of both similarity and difference in growth trajectories of comparably sized lorises and galagos. Furthermore, when ontogenetic profiles of lorisoid and lemurid growth are compared, it is evident that lorisoids grow faster for a shorter period of time.

First Physical Examination of the Horton Plains Slender Loris,Loris tardigradus nycticeboides, in 72 Years

Abstract: We report here the first close examination in 70 years of the Horton Plains slender loris, Loris tardigradus (lydekkerianus) nycticeboides, previously known only from two collected specimens and a number of sightings from eye-shine. Photographic and morphometric data presented here enable a preliminary assessment of the possible distinctive endomorphic features of this loris in comparison to its sister species and subspecies. This loris clearly demonstrates adaptations to montane forest, as previously suggested from the preserved skins of the holotype and paratype. Confirmation of the continued existence of this loris raises familiar concerns over its taxonomic distinctiveness, its apparent low abundance in a highly fragmented and diminishing habitat, and the actions necessary to eliminate the threats to its survival.

Dietary choices by four captive slender lorises (Loris tardigradus) when presented with various insect life stages

The slender loris (Loris tardigradus) is a rare, nocturnal prosimian found only in the tropical rainforest of southern India and Sri Lanka. Little is known about their diet, though it is assumed that insects comprise a majority of their wild diet. Based on this assumption, captive lorises are offered a variety of insects or insect life stages; the species of insect or the life stage is often determined by what is easiest to buy or rear. Captive lorises at the Duke Lemur Center (DLC) were offered the opportunity to choose which life stage of mealworms (Tenebrio molito), superworms (Zophobus morio), or waxworms (Galleria mellonella) they preferred. The DLC captive lorises did not select the largest life stages of any insect offered. They preferred the larvae stage to the adult stage in all three insect species, and males and females had different insect species and life stage preferences.

Habitat quality and availability of the Sri Lanka Red Slender Loris Loris tardigradus tardigradus (Mammalia: Primates: Lorisidae) in the Kottawa Arboretum

The Red Slender Loris (Loris tardigradus) is one of the three primate species endemic to Sri Lanka. Currently there are two recognized subspecies of the Red Slender Loris, the Sri Lanka Red Slender Loris (L. t. tardigradus) and the Sri Lanka Montane Slender Loris (L. t. nycticeboides). Of these, L. t. tardigradus inhabits rainforests in the southwestern region of the island while L. t. nycticeboides is restricted to the montane zone. Kottawa Arboretum harbors one of the few remaining L. t. tardigradus populations in the country. This study was conducted to determine the population density, habitat selection criteria and to asses the habitat availability of L. t. tardigradus in the Kottawa Arboretum. Using the line transect method, 34 sightings were made over a period of 21 months. Based on these observations the density of L. t. tardigradus in the Kottawa Arboretum and habitat selection criteria was ascertained. The calculated density of L. t. tardigradus in the Kottawa Arboretum is 41 animals/ km2. The average height of trees preferred by L. t. tardigradus is 13.97 m plus or minus 6.02. Most of the time lorises were observed at a height range of 3.5-15 m above the ground level. Average height from the ground level where L. t. tardigradus were observed to occupy the tree was 8.64 m plus or minus 5.00. Of the 50 tree species recorded in the Kottawa Arboretum, L. t. tardigradus was found to utilize only 16 species.

Diurnal Primates in Sri Lanka and People's Perception of Them

Five species of non-human primates occur in Sri Lanka—the toque macaque (Macaca sinica), purple-faced langur (Trachypithecus vetulus), slender lorises (Loris tardigradus and Loris lydekkarianus) and the gray langur (Semnopithecus priam thersites). The primates of Sri Lanka are endemic and considered to be Critically Endangered or Endangered. Here we report on some observations, information from interviews with local people regarding primate-human interactions, and also morphological differences in the subspecies we observed during field visits in 2004, 2005, and 2007. When asked, most people stated that they believed that primate populations had increased over the years, and many consider them to be agricultural pests due to the damage they inflict on crops. Due to religious beliefs, hunting and killing of primates were reported in low frequency, but some eat the meat of purple-faced langur for medicinal purposes. The most common methods people use to prevent monkeys from damaging crops are throwing stones, and the use of firecrackers or any other way of producing loud noises. The major threat that these primates face is the destruction of their habitat due to deforestation, human population growth and the expansion of various rural development projects. Public awareness programs for schools and through the media are needed to encourage the protection of these animals and their habitats.

Not all lorises are slow: rapid arboreal locomotion in Loris tardigradus of Southwestern Sri Lanka

The unique slow-climbing quadrupedalism of Asian lorises has been the subject of numerous studies; however, qualitative observations of more rapid locomotion have occasionally been reported. Field studies of the red slender loris have revealed the habitual use of unexpectedly high-speed locomotion by the so-called "sloth of the primate world." Novel video footage permitted the first quantitative kinematic analysis of rapid quadrupedalism in wild lorises. Observations revealed that this previously unexplored behavior is far from infrequent, with 26% of red slender loris locomotor activity being dedicated to high-velocity arboreal quadrupedalism. This locomotor pattern may represent a primitive retention of the rapid, scrambling quadrupedalism that is observed in other strepsirhines, or it may constitute a more recent specialization of this smallest loris taxon.

Kinematics of vertical climbing in lorises and Cheirogaleus medius

The type of climbing exhibited by apes and atelines is argued to have been important in the evolution of specialized locomotion, such as suspensory locomotion and bipedalism. However, little is known about the mechanics of climbing in primates. Previous work shows that Asian apes and atelines use larger joint excursions and longer strides than African apes and the Japanese macaque, respectively. This study expands knowledge of climbing mechanics by providing the first quantitative kinematic data for vertical climbing in four prosimian species: three lorisid species ( Loris tardigradus, Nycticebus coucang, and Nycticebus pygmaeus) that share with apes and atelines morphological traits arguably related to climbing, and a more generalized quadruped, Cheirogaleus medius. Subjects were videotaped as they climbed up a wooden pole. Kinematic values, such as step length and limb excursions, were calculated and compared between species. The results of this study show that lorises, like Asian apes and spider monkeys, use relatively larger joint excursions and longer steps than does C. medius during climbing. These data lend further support to the idea that some primate species (e.g., lorises, atelines, and apes) are more specialized kinematically and morphologically for climbing than others. Pilot data suggest that such kinematic differences in climbing style across broad phylogenetic groups may relate to the energetics of climbing. Such data may be important for understanding the morphological and kinematic adaptations to climbing exhibited by some primates.