Animals, Poisonous and Venomous

T. Dodd-Butera , M. Broderick , in Encyclopedia of Toxicology (Third Edition), 2014

Slow Loris

Introduction

The slow loris, family Lorisidae, genus Nycticebus , is a nocturnal arboreal primate found in Vietnam, Indonesia, and the rainforests of Malaysia. They are considered to be an endangered species as of 2012 and are listed on the IUCN Red List. Their diet consists of insects, bird eggs, small vertebrates, and fruit.

Toxicity

The slow loris is the only venomous primate. Slow lorises have a toxic bite due to a toxin that is produced by the licking a gland on their inner elbow, the brachial organ. Saliva from the slow loris is required to activate the secretion from the arm gland. However, very little else is known about the chemical nature of the toxin. The slow loris bite is reported to be painful in humans with symptoms including burning of the tongue and throat, hypotension, muscle convulsions, heart and respiratory problems, unconsciousness, and even death through anaphylaxis shock.

Treatment

Vaccination against tetanus and antibiotics is often given to bite victims. Treatment is symptomatic for bites and anaphylaxis.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780123864543009842

Skull

Friderun Ankel-Simons , in Primate Anatomy (Third Edition), 2007

Lorisidae

The skulls of Lorisidae, compared with those of other prosimians, give the impression of being dorsoventrally flat, especially in species of genera Perodicticus and Nycticebus. The interorbital distance is generally smaller in Lorisidae than in Malagasy Lemuridae or Indriidae. This narrowness is also seen in lorisids in the lessened postorbital breadth of the skull, or "postorbital constriction." Moreover, among lorisids the snout does not taper toward the front as much as in Lemuridae and thus gives the impression of being less long and pointed comparatively. Among lorisines, the nasal bones are flatter than in Lemuridae. A characteristic elongation of the snout beyond the front end of the tooth row is found in species of the two lorisid genera Arctocebus and Loris. This phenomenon is brought about as a result of their comparatively large premaxillae, the upper margins of which project forward. The nasal bones also enter this projection, thus forming a pipelike nasal opening. In addition, the snout is narrow in Arctocebus and Loris. In Nycticebus, the occipital is flattened and faces backward. The foramen magnum opens most directly backward in Nycticebus of all Lorisidae. Skulls of galagids resemble those of lorisids, but slight differences can be detected. For example, with galagids the cranial vault is slightly more rounded than in Lorisidae, and the interorbital distance is somewhat wider. The postorbital constriction, however, is much more marked in Galagidae than in Lemuridae. The small lacrimal bone at the lower inside corner of the orbit extends considerably forward onto the outside of the orbital wall, and the lacrimal canal (tear duct) is positioned externally. Figure 5.16 shows the skull base of a loris genus Perodicticus.

Figure 5.16. Skull base of a loris genus Perodicticus showing basicranial foramina. 1) Foramen incisivum; 2) f. palatinum major; 3) f. palatinum minus; 4) foramen ovale; 5) foramen lacerum; 6) f. postglenoideum; 7) Tuba auditiva; 8) Meatus acousticus externus; 9) f. condyloideum; 10) f. jugulare; 11) f. caroticum.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780123725769500073

Primates

Barry Berkovitz , Peter Shellis , in The Teeth of Mammalian Vertebrates, 2018

Lorisidae

The lorises and pottos constitute nine species in five genera. They are more omnivorous than lemurs, consuming animal protein in the form of invertebrate or vertebrate prey. The dental formula of the permanent dentition is I 2 2 C 1 1 P 3 3 M 3 3 = 36 . The dental formula for the deciduous dentition is d I 2 2 d C 1 1 d M 3 3 = 24 .

The greater or Sunda slow loris ( Nycticebus coucang) (Fig. 9.8A and B) is largely animalivorous: it preys on mollusks, insects, lizards, birds, and small mammals, but also eats fruit. It has the dental formula I 2 2 C 1 1 P 3 3 M 3 3 = 36 . The upper first incisor is larger than the second, which may be missing. In the dental comb, the lower incisors are thinner than the lower canines. The upper canines are large and pointed. The upper premolars have three roots. The first premolars are the largest and are unicuspid, as is the second, while the third is bicuspid. Of the two-rooted lower premolars, the first is large and caniniform, the second and third are small and unicuspid. The upper molars, which decrease in size from the first to the third, are quadritubercular, with low cusps, although the hypocones on the third molars are small. The lower molars are quadritubercular, but the third has a small fifth posterior cusp, the hypoconulid.

Figure 9.8. Greater slow loris (Nycticebus coucang). (A) Lateral view of skull. Original image width   =   9.1   cm. (B) Occlusal view of dentition. Original image width   =   8.2   cm.

 Courtesy RCSOM/A 112.574.

Slow lorises (Nycticebus spp.) are the only primates to have a toxic bite. The toxin is produced by brachial glands on the forearm. The secretions of this gland are transferred to the mouth by licking and are then mixed with saliva. This combination of fluids has been shown to be lethal against small animals such as mice in experimental tests. The saliva/brachial gland fluid mixture may be retained in the mouth, and can be used in biting, or may be smeared on the fur. The brachial gland fluid contains a protein similar to cat allergen, but also numerous other compounds (Nekaris et al., 2013). Although Nycticebus species kill small animals such as birds and reptiles, it seems unlikely that the venom is necessary for predation (Nekaris et al., 2013). Alternatively, the venom could protect against ectoparasites, deter predators, or enhance the effect of biting by males fighting during competition for females. There is some evidence in support of each of these possibilities (Nekaris et al., 2013).

The gray slender loris (Loris lydekkerianus) (Fig. 9.9) is an omnivore. The diet consists largely of insects, but also includes shoots, young leaves, fruits with hard rinds, birds' eggs, and small vertebrates. It has a dentition similar to that of the slow loris. However, the upper incisors are minute. The upper premolars are, from anterior to posterior, unicuspid and enlarged, bicuspid, and quadritubercular. The first two upper molars are large and quadritubercular. The occlusal surface is divided into two bays by a crest connecting the protocone and metacone. The lower molars are quadritubercular, except for the third molar, which also has a posterior hypoconulid.

Figure 9.9. (A) Slender loris (Loris sp.). Lateral view of skull. Scale bar   =   1   cm. (B) Gray slender loris (Loris lydekkerianus). Occlusal view of dentition. Original image width   =   5.9   cm.

 (A) Courtesy Digimorph and Dr. J.A. Maisano. (B) Courtesy RCSOM/A 112.521.

The potto (Perodicticus potto) (Fig. 9.10A and B) eats fruit and insects, and also collects plant gum. The two upper incisors are approximately equal in size. The upper first premolar is elongated and caniniform, while the last upper premolar is bicuspid. The lower second and third premolars are small. The upper first molars are bicuspid, with a hypocone shelf. The second and third molars have four cusps. The lower first and second molars have four cusps joined by transverse ridges, while the third molar has an extra posterior cusp.

Figure 9.10. Bosman's potto (Perodicticus potto). (A) Lateral view of skull. Original image width   =   8.3   cm. (B) Occlusal view of dentition. Original image width   =   9.0   cm.

 Courtesy RCSOM/A 112.6.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128028186000090

The Taxonomy of Primates in the Laboratory Context

Groves Colin , in The Laboratory Primate, 2005

Appendix

An outline classification of living Primates:

Suborder Strepsirrhini

Infraorder Lemuriformes

Family Cheirogaleidae

Genera: Microcebus, Mirza, Cheirogaleus, Allocebus, Phaner

Family Lemuridae

Genera: Lemur, Hapalemur, Prolemur, Eulemur, Varecia

Family Lepilemuridae

Genus Lepilemur

Family Indriidae

Genera: Indri, Propithecus, Avahi

Infraorder Chiromyiformes

Family Daubentoniidae

Genus Daubentonia

Infraorder Lorisiformes

Family Lorisidae

Genera: Loris, Nycticebus, Perodicticus, Arctocebus, Propotto

Family Galagidae

Genera: Galago, Euoticus, Otolemur, Galagoides

Suborder Haplorrhini

Infraorder Tarsiiformes

Family Tarsiidae

Genera: Tarsius, Cephalopachus, unnamed third genus

Infraorder Simiiformes Platyrrhini1

Family Cebidae

Subfamily Cebinae

Genera: Cebus, Saimiri

Subfamily Aotinae

Genus Aotus

Subfamily Callitrichinae

Genera: Callithrix, Callimico, Leontopithecus, Saguinus

Family Pitheciidae

Genera: Pithecia, Chiropotes

Family Atelidae

Subfamily Alouattinae

Genus Alouatta

Subfamily Atelinae

Genera: Ateles, Brachyteles, Lagothrix, Oreonax

Catarrhini 1

Family Cercopithecidae

Subfamily Cercopithecinae

Tribe Cercopithecini

Genera: Cercopithecus, Allochrocebus, Erythrocebus, Chlorocebus, Miopithecus, Allenopithecus

Tribe Papionini

Genera: Papio, Theropithecus, Lophocebus, Cercocebus, Macaca

Subfamily Colobinae

Genera: Colobus, Procolobus, Piliocolobus, Presbytis, Semnopithecus, Trachypithecus, Pygathrix, Rhinopithecus, Nasalis, Simias

Family Hominidae

Subfamily Hylobatinae

Genera: Hylobates, Hoolock, Symphalangus, Nomascus

Subfamily Homininae

Tribe Pongini

Genus Pongo

Tribe Hominini

Genera: Homo, Gorilla

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780120802616500015

Postcranial Skeleton

Friderun Ankel-Simons , in Primate Anatomy (Third Edition), 2007

EFFICIENCY OF PRIMATE LOCOMOTION

The formulation of locomotor categories is helpful when researchers are discussing the postcranial morphology of primates. There is no other order of extant mammals where body sizes vary between only about 30 grams (dwarf mouse lemurs) up to 170,000 grams (gorillas) and whose general postcranial morphology is so unspecialized that they are capable of practicing an infinite variety of locomotor activities. All efficient locomotor activities are closely correlated not only to the habitat that the animals concerned are inhabiting, but also by their overall size and proportions. It is obvious that a small marmoset cannot be an efficient brachiator. But a gibbon or siamang is perfectly adapted to the brachiating mode of locomotion. In contrast, gibbons lack the appropriate size and proportions to be efficient bipedal striders like humans. Even though humans can move more or less efficiently by arm swinging and gibbons can walk upright, neither one of these activities can be perpetually beneficial for them.

It is unfortunate that the terminology of most locomotor categories is unsatisfactory. It has traditionally been difficult to define such categories. For example, the term "semibrachiation" should be abolished as it is not possible to define it properly. The locomotor category "vertical clinging and leaping" is only appropriate for tarsiers, some of the galago species, and the indriids, and should not be applied to superficially similar locomotor activities of other primates such as South American monkeys. This is the case because true vertical clinging and leaping is morphologically distinct in the three groups of prosimian primates that unmistakably use this mode of locomotion. And this morphological manifestation actually varies even within the VCL category as the three groups of primates that are locomoting in this mode have characteristically different adaptations in their hind-leg anatomy. Also, Fleagle (1992) states that leapers "have relatively long hind limbs and long, flexible backs, particularly in the lower (lumbar) region." This is, for example, actually not true for tarsiers, whose lumbar region is rather stout and not near as flexible as those of monkeys such as callithrichids.

Limb proportions have been used widely as indicators of the locomotor type used by various primates. Among the apes a common morphological feature is the length of the forelimbs. All apes have elongated arms, a feature that is most evident in the lesser apes. These elongated forelimbs erroneously were regarded as indicating that all apes were arm swingers. In 1970, C.J. Jolly demonstrated that forelimb elongation need not necessarily correlate with arm swinging or brachiation. Jolly studied very large, extinct open-country baboons and concluded that they were too large to be able to live in trees. They lived in arid environments and yet had long forelimbs. Some of these huge baboons were as large as female gorillas and at least one species had much longer forelimbs than hind limbs. They were at first ranked in their own genus Simopithecus, but Jolly realized their similarity to the present-day gelada baboon Theropithecus and placed them in this genus. The gelada baboon is a highly terrestrial primate that lives today in the treeless high country of Ethiopia and is totally unable to use arm swinging locomotion.

It has been documented that the robusticity of the forelimb bones is greater in terrestrial monkeys than in arboreal monkeys while the hind limbs are relatively long and strong compared to the predominantly terrestrial primates (Kimura, 2003). These results have been confirmed by laboratory testing that relates peak hind limb to forelimb force during terrestrial versus arboreal locomotion (Schmitt and Hanna, 2004). These authors were able to document that the peak load difference varies notably more in forelimbs as compared to hindlimbs: the forelimb load force is reduced during arboreal locomotion.

The important factor of above branch balance during arboreal quadrupedal locomotion has been studied in five Old World monkey species (Larson and Stern, 2006). It is stressed that successful maintenance of balance during walks and runs on small branches depends to a great extent on the involvement of long tails. It is discussed that the morphology of the elbow joint provides forearm stability in hominoids during pronation and supination. It is suggested that the morphology of the elbow joint of early hominoid primates (lateral trochlear ridge on the distal end of the humerus; Rose, 1993) is suitably adapted to assist with balance, suspensory activities, and stability in a wide range of locomotor activities.

A recent study compares body proportions and locomotion of two closely related cercopithecines (Anapol et al., 2005). It is concluded that differences in body proportions between the two species can be attributed to the (slight) differences in locomotor activities. Even though it appears that other factors such as sexual dimorphism can alter the true relationship between body proportion and locomotor activity.

One possible and useful approach to classify locomotor behavior of primates requires measuring the percentage of time that is spent using specific locomotor patterns during periods of activity. Let us look at the locomotor activities of modern humans to illustrate this approach. For example, how much time does the average adult human being spend moving about in the typical upright walking locomotion? Between 10 to 50% of the active time during a 10-hour average day is said to cover the extremes. Equally important for our understanding of human locomotion and postcranial morphology is the time adult humans engage in different locomotor activities such as climbing, swimming, running, bike riding, ice skating, skiing, dancing, raking, digging, or driving automobiles: all activities humans are capable of doing, all activities that can be categorized as locomotion. These secondary locomotor activities, however, are less significant adaptively than human upright, bipedal walking. This illustrates that a normal adult human locomotes predominantly by walking bipedally, and we can justify their locomotor classification as bipedal walkers. On the other hand, it has been averaged for today's true brachiators, the lesser apes, that they brachiate about 80% of the time when actively moving. Therefore, they are correctly assigned to the locomotor category "brachiation."

It does not prevent a primates with long arms such as gibbons or great apes from walking bipedally on their hind legs, equally as the elongated tarsals of prosimians do not exclude them from moving about in a quadrupedal manner. We all know that morphologically and behaviorally bipedal humans are capable of engaging in all manner of locomotor behaviors that are not easily deducible from their specialized hind-limb and pelvic anatomy. Basically, all primates can be made to move about in manners that are not their habitual locomotor pattern. It is this unlimited ability to locomote in various ways that makes primates highly adaptable and difficult to assign to precise locomotor categories.

In a recent study Lemelin and Schmitt (1998) investigate the relationships between primate hand anatomy and lococomotor behavior with the help of kinematic documentation. They follow Jouffroy et al. (1991) in their definition of three types of primate hands that are based on morphological data:

1.

Ectaxonic hands, as in Nycticebus where the fourth ray is the longest, which are characteristic for "strepsirhine" primates.

2.

Mesaxonic hands, which have a longer third ray and are said to be found in most "haplorhines."

3.

Paraxonic hands, where rays III and IV are nearly equal in length as in some cebid monkeys.

Lemelin and Schmitt state "Clearly, primates with mesaxonic or paraxonic (i.e., Ateles) hands are capable of using a wide range of hand positions that appear to vary according to substrate differences," and finally conclude: "This evidence suggests that hand kinematics is adjusted (sic) according to the substrate rather than being constrained by the anatomy. Also differences in how ulnar deviation was achieved (either at the midcarpal joint or at the metacarpophalangeal joints) reflected an intriguing phylogenetic signal that separated Lorisids and cercopithecids." This conclusion confirms that often functional potential supersedes functional anatomical adaptation in primates.

The relationship of environment, body size, and locomotion of primates can be analyzed during field studies. The relationship between postcranial anatomy and locomotion can best be understood through analysis in the laboratory. An increasing number of such studies have been carried out over the years. Brief reviews of some of these most instructive research projects will illustrate what can be learned from this kind of analysis.

Fleagle's (1977a, b) research on two sympatric species of Malaysian leaf monkeys, Presbytis obscura (Trachypithecus obscurus) and P. melalophos, provides valuable insight of possible correlations between locomotor behavior, substrate use, and anatomical structure. 1 He found P. obscura to be primarily a quadrupedal monkey that prefers to move on large supports. In contrast, P. melalophos leaps much more frequently and prefers to locomote on smaller supports. Further, P. obscura spends the majority of its time in the horizontally continuous main tree canopy, whereas P. melalophos frequents the discontinuous lower level of the forest. Finally, Fleagle has documented a number of statistically significant anatomical differences between these two species. In each case these differences make structural sense when considered with the locomotor behaviors of these primates in mind.

Mittermeier and Fleagle (1976) carefully compare and evaluate similarities and differences in the locomotor behavior of Ateles geoffroyi and Colobus guereza and spell out the uselessness of locomotor categories such as "semibrachiation." Both these monkeys have repeatedly been classified as "semibrachiators," but it turns out that their locomotor behaviors are as different as can be. Also, the authors caution that it is almost certainly misleading to generalize locomotor behavior from one particular population to other populations of the same species. Troops that live in different environments often exhibit clear-cut locomotor differences within the same species, differences that are thus not likely to be reflected in the morphology.

Another interesting field study is that of Fleagle and Mittermeier (1980), in which they document the locomotion of seven species of New World monkeys in relation to these monkeys' body size and ecology. For the seven species studied—Saguinus midas, Saimiri sciureus, Pithecia pithecia, Chiropotes satanas, Cebus apella, Alouatta seniculus, and Ateles pansicus—the authors noted the following trends: smaller forms tend to leap more than larger forms, whereas larger forms habitually climb more than smaller forms. Also, larger monkeys tend to prefer larger supports. However, these trends have two exceptions. Saguinus preferred relatively larger, and Ateles preferred relatively smaller substrates than would be predicted from body size alone. Finally, these authors found no relationship between locomotor behavior and diet.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780123725769500103

Husbandry and Management of New World Species: Marmosets and Tamarins

Rensing Susanne , Oerke Ann-Kathrin , in The Laboratory Primate, 2005

Parasitic diseases

The Acanthocephalan Prosthenorchis elegans penetrates into the wall of small and large intestines, mainly the lower ileum and caecum as far as the serosa, resulting in ulceration, necrosis, perforation and peritonitis. Trichospirura leptostoma is a spiroid nematode that inhabits the pancreatic duct of common marmosets. Animals with high parasitosis have moderate to severe fibrosis in the pancreas (Hawkins et al., 1997). Clinical symptoms are weight loss and increased faecal volume. 50 mg/kg Fenbendazol SID for 14 days is the most effective treatment.

Severe pterigodermatitis (Rictularia nycticebus) is manifested by diarrhoea, weakness, hypoproteinaemia and anaemia. This spiroid is attached to the small intestines and may be treated with Mebendazol or Ivermectine. Cockroaches are the reservoir hosts and should be eliminated ( Potkay, 1992).

Giardia lamblia is a flagellate protozoan found world-wide, infecting humans and animals. Clinical signs range from none to watery bloody mucoid diarrhoea, associated with abdominal cramps, bloating, anorexia and nausea (Kalishman et al., 1996). Other protozoal infections are Balantidium spp. and Entamoeba spp. Entamoeba histolytica produces cysts in the liver, whereas E. dispar is apathogenic but can also result in diarrhoea, anorexia, weakness, abdominal pain and nausea. Natural infections are very uncommon. Drug of choice is Metronidazol or Paramomycinsulfate.

New World Primates are very sensitive to infections with Toxoplasma gondii. Transmission is mostly by ingestion of sporulated oocysts shed by felidae, or diaplazentar (Potkay, 1992). Death occurs after 5–6 days with non-specific clinical symptoms like anorexia, weakness, fever, coughing, dyspnoe, leukopenia and abortion.

Filariasis can be overwhelming with thrombus-like occlusions of small vessels in the lung, heart muscle and liver.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780120802616500106

Brain

Friderun Ankel-Simons , in Primate Anatomy (Third Edition), 2007

LEMURIDAE AND LORISIDAE

Among extant prosimians the smallest representative, Microcebus, has what seems to be the simplest brain, probably mainly because of its small body size. The mouse lemur's brain is lissencephalic. A deeply engraved sylvan fissure is present. The olfactory bulb is partly covered above by the frontal lobes of the brain.

In genus Eulemur the olfactory region is more reduced than in Microcebus. The neopallium is convoluted and exhibits sulci that are mainly longitudinally directed. Many present-day prosimians retain well-developed olfactory regions (e.g., Daubentonia, Nycticebus, and Galago). Also, the long snoutlike nasal region of Eulemur as well as the shorter snout of Propithecus are still structured like that of animals with a highly developed olfactory sense (Starck, 1962). As we have seen, long snouts are not necessarily correlated with olfactory acuity.

Morphological differences would be expected in the visual area of the brain of the predominantly diurnal lemurs and the nocturnal lorisoids; this is not the case. It seems that the requirements of nocturnal visual acuity are not too different from diurnal vision because the intrinsic morphologies of the lorisoid and lemuroid brains, as far as we know, are very similar with one exception: the lateral geniculate bodies that are part of the diencephalon (thalamus) and are situated on the sides of the mesencephalon are the location where most of the optic tract fibers are ending. This large and complex visual center is increasingly complex, setting out with the rather simply organized lateral geniculate of Tupaia, getting more intricate across all the other primates with increasingly elaborate areas, and culminating in the most complex lateral geniculate bodies among primates—those of humans. The arrangement of the position of the lateral geniculate bodies in relation to the thalamus is different in the various primate genera. These different positions change the arrangement of the insertion area of the optical fibers. The lateral geniculate bodies are located laterally to the thalamus in Tupaia, in various ventrolateral positions in genus Eulemur, and ventrolaterally in Tarsius; they move ventrally and rotate in higher primates. There are microscopically distinctive layers or lamina of different neurons: layers made up of large, macrocells, and layers made up of parvo (small) cells. The cell layer arrangement is more uniform in higher primates than in prosimians. The macrocell layers are inverted (convex from outside) in prosimians including Tarsius but positioned differently, laterally in lemurs and tarsiers and ventrally in Perodicticus, a representative of the lorisoids. Unlike any other primate, the innervation of the dorsolateral geniculate bodies is reversed in tarsiers (Rosa et al., 1996). No other positional differences of the specific cell layers between the lemurid and lorisoid prosimians have been noted (Noback and Moskowitz, 1963).

Overall the brain morphology of Daubentonia madagascariensis (aye-aye) is unusual among primates in general and lemurs in particular. The relatively large olfactory bulbs are overlapped by the frontal part of the brain and deflected downward. The brain shows more convolutions than any other prosimian primate (Stephan and Bauchot, 1965). This unusual size and structure of the brain of the aye-aye appears to be closely correlated to the bizarre morphology of the skull and unique hands and the highly intelligent foraging behavior of this prosimian (C. J. Erikson, 1995).

Among the non-Malagasy prosimians, the Asian genera Nycticebus and Loris have more cerebral convolutions than do the brains of bushbabies. Information about the degree of gyrification of the two African lorisoids Arctocebus and Perodicticus are wanting.

It appears that attempts to find functional homologies of brain regions among various primates are often confounded by the fact that such homologies do not exist (Sereno and Tootell, 2005). This fact has been shown by these authors for visual regions. It also is made clear that effects of body size are difficult to correlate in any reliable way to the factor encephalization.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780123725769500085

TROPICAL LOWLAND EVERGREEN RAINFOREST

Friedhelm Göltenboth , ... Peter Widmann , in Ecology of Insular Southeast Asia, 2006

Nocturnal Organisms

Night fall in a tropical forest is like the scene change in a short period of time. Photosynthesis ceases and the daytime animals of the forest floor and the canopy withdraw to find safe refuges. As the daytime animals retire a complete new suit moves out from their daytime refuges and very often fill in the niches left by the daytime organisms.

While more than 90% of the birds are diurnal, about 80% of the mammals are either crepuscular or active at dawn and dusk, or nocturnal. True nocturnal species have developed several specialised features that enable them to make optimal use of the darkness:

•

Eyes must be constructed in such a way that they are capable to receive any available light; e.g. owls, slow loris ( Nycticebus sp.), tarsier (Tarsius sp.) and forest cats (Panthera tigris, Panthera pardus) have developed large eyes, or can change the pupils size.

•

Hearing is very essential and navigating by sound is one mean to avoid obstacles and to locate food; e.g. bats, said to be the most successful group of night creatures with members belonging to a wide range of dietary niches including fish-eating bats, insect-eating bats, nectivorous bats and fruit-eating bats.

•

Sensory organs able to locate by smelling a mate or food items; e.g. moths, able to locate a mate over more than a kilometer distance with the help of pheromones, bats smelling fruits and flowers in the dark.

•

Communication by sound; e.g. grasshoppers, crickets, cicada and frogs, the latter two making the short time of dusk to one of the noisiest parts of the daily cycle in a forest.

•

Flashing of a phosphorescent light; e.g. male fireflies signal their presence by an intermitted rhythmic flashing, the sequence of which is unique to each species.

Geckos emerge from cracks. This is one of the rare reptile groups being able to call, and have followed the settlers and are one of the most successfully established former forest organisms in inhabited areas. Snakes find their prey with the help of temperature receptors on the front of the head. Owls fly absolutely noiseless through forest gaps and along forest edges in search of prey.

The different nocturnal mammals have developed very different means of locomotion:

•

The folivour flying squirrels (e.g. Petaurista petaurista) emerge from their daytime hideouts. So do the vegetarian Flying lemur (Cynocephalus varigatus) both able to glide rather than to fly from tree to tree. By this means they both are able to range widely to exploit large food sources.

•

The carnivorous Palm civets, e.g. Hemigalus derbyanus range widely by decending to the ground.

•

The omnivorous Slow lories move very slowly and carefully in the understory level, covering a small home range of only 5-10 ha (Barrett, 1984).

•

The prosimian mainly insectivorous tarsiers (Tarsius spectrum, Tarsius bancanus) leap from trunk to trunk.

•

The porcupine, Thecurus crassispinis, is noisily searching for starchy roots fearing no predator due to its ability to charge backwards sharp spines.

•

The bats leave their daytime resting sites and fly long distances in search of either fruits or prey.

The ecology of the forest at night is as complex as by day. Only the larger mammals roam the forest by day and night but the arboreal community is more clearly divided into diurnal and nocturnal groups (MacKinnon et al., 1996).

The Malay pangolins, Manis javanica, exploits during its nocturnal life a dietary niche which is mainly vaccant during daytime. Most others, particularly the bats and the moonrat (Echinosorex gymnurus), an evil-smelling large insectivore in Borneo and Sumatra, share resources that are exploited by other forest residents during the daytime. In the case of the moonrat this is the tree shrew feeding on beetle grubs, earthworms and insects.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780444527394500176

Chromosomes and Blood Groups

Friderun Ankel-Simons , in Primate Anatomy (Third Edition), 2007

Karyotype Evolution

Theories on how the extant primate karyotypes have evolved are numerous (Eder et al., 2003). Dutrillaux et al. (1986) constructed so-called ancestral karyotypes for lemuriformes in particular and primates in general to provide basic, hypothetical karyotypes that make comparison with extant karyotypes possible. Overall, the primary assumption is that the number of chromosomes is more likely to be reduced over time than to increase. Many prosimians (and some other primates also) have a high number of acrocentric chromosomes when they have a high diploid number and vice versa. This observation has led to the conclusion that fusion of acrocentric chromosomes to form metacentrics with a concomitant decrease of the total chromosome number in a given karyotype is an important mechanism in primate karyotype evolution. Evidence that karyotype rearrangement in genus Eulemur, for example, has taken place primarily by centric fusion of acrocentric chromosomes to yield metacentrics has been provided by chromosome banding studies. Banding analysis confirmed the homology of the arms of most of the metacentric chromosomes in species that have lower diploid numbers with the acrocentrics in species that have higher numbers (see Rumpler and Dutrillaux, 1976; Rumpler et al., 1988). However, if fusion of a high number of original acrocentric chromosomes led to the many metacentric chromosomes and smaller diploid chromosome numbers in higher primates, the lorisid prosimian Nycticebus coucang presents a problem, because all of its 2n = 50 chromosomes are metacentric or submetacentric.

Another general assumption, that primates with high numbers of chromosomes are morphologically and functionally less advanced than primates with low diploid counts, does not always fit with the taxonomic picture derived from the study of gross morphology and behavior in primates. Tarsius, for example, is by no means a generalized primate but is an extraordinarily derived prosimian, and it has the highest chromosome number of all primates at 2n = 80, with 7 pairs of metacentric or submetacentric chromosomes and 33 pairs of acrocentric chromosomes. Dutrillaux and Rumpler (1988) document that the karyotype of T. syrichta is not only totally unlike those of any other primate they have studied, but also is not similar to any mammals belonging to other orders that have chromosome segments or entire chromosomes in common with primates.

Within the New World monkey family Callitrichidae, explanations for the possible course of karyotype evolution are very intriguing and even convincing. The basic mechanism is believed to be fusion of acrocentric chromosomes into fewer submetacentrics or metacentrics. Additional knowledge has been derived and adds a different aspect to evolutionary speculations from the occurrence of chromosome chimerism in Callitrichidae. A chimera is an individual animal whose cells have more than one different genotype, usually caused by a single individual developing from an embryo that is created through fertilization by cells from two different individuals with different genotypes (e.g., two sperms successfully fertilize one ovum). The fact that marmosets usually give birth to twins or even triplets might be one of the reasons for the occurrence of individuals with chimerism (Ford and Evans, 1977). Among primates cell chimerism is only found in Callitrichidae with a twin of the opposite sex, and the chimerism affects the sex chromosomes (Goldschmidt et al., 2005). Consequently, a certain percentage of the cells in one individual are karyologically male and the others are female. The occurrence of chimerism in marmosets has been explained by cell exchange in very early fetal stages of heterosexual dizygotic twins through the anastomoses of blood vessels in connected chorions. A pair of autosomes can also be heterozygous in species of Callithrix. The existence of such heteromorphic autosomal pairs in living individuals of Callitrichidae suggests that the two different autosome types do not affect the individual's ability to produce fertile offspring. The phenomenon of twinning and karyological chimerism—callithrichid twins are genetically as different from each other as regular siblings—has been implicated in behavioral aspects of marmoset life such as paternal care and mating systems (Haig, 1999).

Ford's detailed discussion concerning possible avenues of speciation in genus Aotus (1994) is an excellent example for evolutionary speculation about karyological variants and their geographical distribution in an evolutionary context. Karyotypic speciation in genus Aotus is assumed to proceed by fusion of acrocentrics into metacentrics accompanied by a reduction of the diploid chromosome number rather than by fission events and an increase of diploid chromosomes. Ford also examines the relationships of owl monkey (Aotus) populations, evaluating their electrophoretic blood protein similarities. Although the chromosomes make evolutionary speculations about Aotus populations possible, the electrophoretic results remain inconclusive.

Chromosomal evolution among cercopithecines is said to be very complex and appears to show an increase, rather than the predicted reduction, of the number of chromosomes over time (Dutrillaux et al., 1988).

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780123725769500140

Comparative Anatomy of Primates

Rui Diogo , ... Adam Hartstone-Rose , in Basics in Human Evolution, 2015

The Strepsirrhine Skeleton

There is almost as much skeletal diversity among the extant galagos, lemurs, and lorises (modern members of the suborder Strepsirrhini; see Figure 1) as there is in the whole order. If you include a consideration of the recently extinct lemurs, then this suborder certainly has had more variation in size, shape, posture, and locomotion than all of the living anthropoids combined. This group ranges in size from the diminutive mouse lemurs (Microcebus)—as small as 30   g, the smallest of all living primates—to the ∼6   kg indri (Indri). While this largest of living lemurs is not particularly impressive in size relative to hominoids and some monkeys, all of the recently extinct lemurs were larger than their surviving relatives. The largest of these, Archaeoindris, may have been nearly 200   kg—larger than most of the living hominoids. As impressive as they are in size, most of the recently extinct lemurs were even more interesting in their locomotor adaptations, with several species (Archaeolemur and Hadropithecus) converging on a more terrestrial monkey-like form, other giant forms displaying a bizarre form of arboreal morphology that included exceptionally long and curved digits and other skeletal elements that have given them the moniker the "koala lemurs" (Megaladipis). As strange as this taxon was, another extinct lineage (including Babakotia and Paleopropithecus) had distinct adaptations for underbranch suspension that has given them the name "sloth lemurs" (Mittermeier et al., 2006).

Figure 1. Scheme showing the main primate clades and their phylogenetic relationships. (See color plate section).

The living strepsirrhines mostly have more typical body forms that can generally be divided into four categories: (1) relatively small slow bodies (e.g., those of the slow loris, Nycticebus , and dwarf lemurs, Cheirogaleus) that may represent the body plan of the most primitive ancestral primate; (2) small bodies built for quick movement (e.g., the bush babies, Galago, and mouse lemurs, Microcebus); (3) arboreal quadrupeds (e.g., ringtail lemurs, Lemur, and the "true" lemurs, Eulemur)—what most may think of as a typical lemur form; and (4) the "vertical clinging and leaping" lemurs (e.g., the indri, Indri, and sifakas, Propithecus). Almost all of the living strepsirrhines fall more or less within one of these categories with one amazing exception: the aye-aye (Daubentonia). This truly unique animal has a suite of morphology unlike any other primate: as the largest of all nocturnal primates, it has huge ears that it uses in combination with exceptionally long fingers to echolocate wood-boring insects in a feeding method known as "tap foraging." Once it locates an airspace beneath the surface of the wood, it uses its ever-growing incisors (also unique among primates and almost all other mammalian orders) to gouge into those cavities, and then it inserts its long, thin, and highly flexible middle finger into the hole to probe and fish out grubs. This, along with its impressive long and bushy tail, vestigial premolars and molars, inguinal mammaries (breast located in the groin) and highly cryptic behavior, clearly makes this sole member of its own family a truly mysterious primate (Mittermeier et al., 2006). It is arguably one of the strangest of all mammals.

Exceptions aside, strepsirrhines have a fairly typical primate skeleton: substantial clavicles and opposable, powerful big toes. All have fairly large eyes surrounded by "postorbital bars"—bony struts connecting the frontal bone to the zygomatic arch to either support or protect the relatively convergent eyes. Most strepsirrhines have long tails and typical primate molars and premolars (albeit relatively primitive). Most also have "tooth combs"—a reorganization of the lower anterior dentition (incisors and canines) in which these teeth are long and thin and aligned as an apparatus used for grooming. They also have a "grooming" or "toilet" claw—a long sharp claw generally found on the second toe. The truly defining feature of the group—the wet "rhinarium," essentially a continuity between the upper lip and nose that allows improved use of the vomeronasal organ—is a predominantly soft-tissue feature. However, the strepsirrhine emphasis on olfaction does highly influence the shape of the skull: more than any of the other primates, lemurs have fairly elongated rostra. This anatomy allows for greater olfaction—a more important sense in this group than primates such as hominoids (as exemplified by the nearly ubiquitous scent glands used by these animals)—and makes the skull longer than almost all other primates (Hill, 1953; Fleagle, 1999).

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128026526000049