The skin of primates. XXXIV. The skin of the golden spider monkey (Ateles geoffroyi)

The skin of the golden spider monkey (Ateles geoffroyi) has many histological and histochemical similarities to that of the woolly monkey (Lagothrix lagotricha) and howler monkey (Alouatta caraya); however, this monkey possesses certain peculiar properties such as large sebaceous glands, a combined distributional pattern of eccrine and apocrine sweat glands, and abundant alkaline phosphatase in the sebaceous glands, apocrine and eccrine sweat glands. In brief, the anatomical and histochemical properties of the skin of this animal are more similar to those of the howler monkey than to the woolly monkey. In addition, the skin of these three Ceboids falls phylogenetically between that of the Cercopithecoidea and Pithecoidea.     

Differentiation of vocalizations in bushbabies (Galaginae, Prosimiae, Primates) and the significance for assessing phylogenetic relationships

A comparative bioacustic analysis of vocalizations of the prosimian subfamily Galaginae revealed that morphologically similar sibling taxa within the main groups of the lesser galagos and the greater galagos can be reliably identified phenotypically on the basis of the acoustic structure of their loud call or advertisement call. Results confirm the separation of two distinct species of greater galagos, Galago crassicaudatus and Galago garnettii, and strongly suggest the discrimination of three distinct species from the senegalensis lesser bushbaby group, Galago senegalensis, Galago moholi and Galao zanzibaricus. An investigation of the ontogenetic development of the loud call indicated that it is derived from the infant's isolation call, displaying in all studied bushbaby taxa a fairly similar acoustic pattern. Shared acoustic characters of the loud call among the different taxa as well as the infant's isolation call were used to propose a hypothesis about the phylogenetic affinities in bushbabies. The results seem to be supported by recent fossil records.     

The skin of primates. 33. The skin of the Angwantibo (Arctocebus calabarensis)

The general behavior, locomotion, and body from of the angwantibo resemble those of Loris and Nycticebus. Its skin, however, is similar to that of Pottos and Galagos; singular among the similarities is the occurrence of alkaline phosphatase-positive dendritic cells in the epidermis. The presence of elongated, sausageshaped end-organs in the mucocutaneous region, the absence of arrector pili muscle, and the absence of alkaline phosphatase in the hair follicle nerve end-organs are distinctive features of angwantibos. These animals have a well-formed, complete nictitating membrane, thereby differing from all other primates studied.     

Brief communication: Histology and micro CT as methods for assessment of facial suture patency

The extent of fusion in facial sutures has implications for topics ranging from biomechanics to phylogeny reconstruction. An unfortunate limitation of studying sutural fusion in skeletal specimens is that it is difficult to assess whether apparently patent sutures are in fact fused internally. Both histology and microcomputed tomography (CT) are potential tools for solving this, but relatively few studies have attempted to discern the limits of micro CT for visualization of microanatomical structures. We examined microanatomical aspects of facial sutures in adult cadaveric samples from captive bushbabies. Premaxillary and nasopremaxillary sutures were examined in serially sectioned snouts of four greater bushbabies (Otolemur garnettii) and four lesser bushbabies (Galago moholi). Sections containing sutures with osseous bridging were rated as “fused,” and the presence or absence of grooves on the external side was recorded. One bushbaby was studied using micro CT prior to physical sectioning. O. garnettii and two of the G. moholi show multiple foci of fusion. Histological examination confirmed that sutural fusion is limited to the internal surface in numerous sections, resulting in an external notch. Such points of internal fusion could be clearly visualized in raw CT slices. The presence of such notches suggests that external examination can underestimate the degree of suture fusion. Thus, microanatomical evidence may be needed to fully assess biomechanical correlates and phylogenetic interpretations based on fusion of facial sutures. Our results also indicate micro CT may be a useful tool to obtain this evidence. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

The skin of primates. XXX. The skin of the woolly monkey. (Lagothrix lagotricha)

The anatomical and histochemical features of the skin of the woolly monkey are intermediate between those of the Cercopithecoidea and the Pithecoidea. The animal has a prehensile tail, the glabrous, friction surface of which is similar to that of the fingers. The epidermis is heavily pigmented. The dermal vascularization is relatively well-developed and similar to that of the skin of the Cercopithecoidea. Hair follicles grow in groups of 4 to 15, as in the skin of the Pithecoidea. In the hairy skin, eccrine sweat glands occur only in the tail and genitalia. The woolly monkey, like the green monkey, possesses only acetylcholinesterase-containing nerve fibers around its eccrine sweat glands.     

The skin of primates. XXXVI. The skin of the pigmy marmoset--Callithrix (Cebuella) pygmae

The pigmy marmoset — Callithrix (= Cebuella) pygmaea Spix — is the second detailed study of the members of the family Callithricidae. It is closely allied to the red-mantled tamarin — Saguinus (=Tamarinus) fuscicollis illigeri Spix — and shares some of its characteristics with both Prosimii and Anthropoidea. The epidermis and dermis contain moderate numbers of concurrent, melanotic melanocytes. The dermis is rich in elastin. Hair follicles grow in groups of three or four over the general body surface, and one apocrine gland is associated with each grouping. Arrectores pilorum muscles are well developed. On the ventral ulnar wrist are sinus hairs associated with apocrine glands. Most hair follicles have nerve end-organs around them that are reactive for acetylcholinesterase and alkaline phosphatase. There is a large aggregation of sebaceous glands in the suprapubic region. The large sebaceous glands in the eyelid, face, and external genitalia are surrounded by cholinesterasereactive nerves. Apocrine glands are found over most of the hairy skin except the brow, scalp and back; a large grouping of them is present in the sternal region. Only the secretory coils of apocrine glands in the external genitalia are invested with butyrylcholinesterase-rich nerves. Eccrine glands are confined to the volar surfaces of the pes and manus. They have dark cells with abundant glycogen and clear cells with neither glycogen nor PAS-reactive material. The nerves around the eccrine secretory coil are reactive only for acetylcholinesterase.     

Classical heinrothian intimidation displays exhibited byGalago demidoff demidoff: A paradigm for pinpointing galagine species diversity

The existence of rhythmic micturation displays among bushbabies is well established but the function of such behavior has been a source of dispute, due largely to indiscriminate lumping of different kinds of phenomena. In this paper classical ethological evaluation of the rhythmic micturation intimidation displays regularly exhibited by dominant adult Galago demidoff demidoffallows comparison with other varieties of intra- /interspecific displaying and agression. These include (1) pure offensive behavior shared by both sexes; (2) defensively toned, antiintruder/antipredator displaying; (3) male- male rank demonstration confrontations; and (4) dominant- female, emotionally neutral self- advertising. The dominant- male, offensively toned displays couple the functions of rival intimidation and partner attraction; they vary between different species of bushbaby, and they represent an important taxonomic tool.     

The skin of primates. XXXI. The skin of the black-collared tamarin (Tamarinus nigricollis)

The black-collared tamarin represents the first detailed study of a member of the family Callithricidae. Although certain features are unique, some of its characteristics resemble those of Prosimii and those of Anthropoidea. The epidermis is moderately pigmented, and the dermis contains numerous elestic fibers. Scattered melanocytes are found throughout both layers. Hair follicles grow in groups of 3 to 4 over the general body surface, including the muzzle. One apocrine gland is associated with each hair group. In the periinguinal region is a large concentration of gigantic sebaceous glands. Apocrine glands occur over the entire hairy skin. Aggregations of these glands on the ventral wrist (in conjunction with sinus hairs) and chest represent the ulnar gland and suprasternal gland, respectively. Apocrine secretory coils of the ulnar gland and external genitalia are surrounded by melanotic, dendritic melanocytes. Eccrine sweat glands are confined to the volar surfaces of the pes and manus. Cholinesterase-reactive granules are dispersed throughout the cytoplasm of the myoepithelial cells.     

The skin of primates. XL. The skin of the cottontop pinché Saguinus (=Oedipomidas) oedipus

The skin of Saguinus (= Oedipomidas) oedipus Linnaeus, is basically similar to that of the red-mantled tamarin, Saguinus (= Tamarinus) fuscicollis Spix; it has several peculiarities: (1) a circumscribed tuft of vibrissae on the ulnar aspect of the wrist; (2) an accumulation of apocrine glands over the sternum; and (3) an extensive posterior abdominal field of gigantic sebaceous glands admixed with large apocrine glands, better developed in the female. The epidermis, dermis, hair follicles, sebaceous ducts, and apocrine excretory ducts are all heavily pigmented. Hairs are arranged in linear perfect sets; the epithelial sac of quiescent follicles is devoid of glycogen and phosphorylase. Eccrine sweat glands are restricted to the volar friction surfaces and contain no glycogen. Only the coiled excretory ducts of the eccrine glands contain phosphorylase. All cutaneous nerve fibers are more reactive for acetylthan butyrylcholinesterase.     

Digestive strategy of the south-east African lesser bushbaby, Galago moholi

Galago moholi is a small nocturnal primate, which has a specialised diet of Acacia exudate and insects. Both exudate and insect exoskeletons contain beta-linked polysaccharides that can be used as an energy source by mammals via microbial fermentation. The morphology of the gastro-intestinal tract of G. moholi suggests that the complex, elongate caecum, proximal colon and ansa coli are most likely to be the fermentation compartment. The results of a digesta marker study showed that there was selective retention of the fluid phase of the digesta, a pattern commonly seen in small caecum-fermenting mammals. There was also retention of the particle marker in the gastro-intestinal tract. Comparison to these results with those from other mammals, including other bushbaby species, suggests that this was due to retention of particulate digesta in both the stomach and the ansa coli, a U-shaped loop in the proximal colon. The digestive strategy of the south-east African lesser bushbaby is best described as caeco-ansal fermentation, as the caecum, proximal colon and ansa coli function as distinct fermentation chambers. However, we contend that, because it is soluble polysaccharides in exudates travel with the fluid phase of the digesta, reach the hindgut sooner than particles of the insect exoskeleton, and are fermented faster than particulate digesta, that lesser bushbabies, in spite of their small size (approximately 200 g) are able to include an apparently low-quality food (exudate) in their diet.     

The skin of primates. XLI. The skin of the silver marmoset—Callithrix (= Mico) Argentata

The skin of the silver marmoset, Callithrix (= Mico) argentata Linnaeus, has many outstanding characteristics. The unusually thin epidermis and dermis are generally devoid of melanotic melanocytes. The surface of the interramal gular region is peppered with small, elevated papillae; that of the corpus penis is characterized by keratinized, proximally directed hollow spines in whose cavities are organized nerve end-organs and capillary loops. Cholinesterase-reactive papillary nerve end-organs and Meissner corpuscles populate all volar friction surfaces. A highly vascular dermis and subcutaneous fat pad partially contribute to the characteristic rubicund color of the face, external ears, and anogenital region. Many body surface hairs are accompanied by the classic Haarscheibe of Pinkus. Sinus hairs are plentiful; a circumscribed vibrissa-bearing eminence is located on the ventral ulnar aspect of each wrist. Alkaline phosphatase-positive, stellate-shaped cells are found on the outer root sheath and epithelial sac of active and quiescent hairs in all cephalic regions; such cells are not argyrophilic, aurophilic, or osmiophilic. Hairs grow in linear perfect sets of 3 to 5 follicles; they do not grow singly on the cheek. Large sebaceous glands contain alkaline phosphatase in their peripheral acini; extensive fields of gigantic multilobular sebaceous glands contribute to the distinct, opaque-white color of the scrotal skin. Numbers of apocrine sweat glands are diminished in cephalic regions but one gland occurs with each hair follicle in the axilla, scrotum, suprapubic region, and ulnar eminence. Relatively avascular eccrine sweat glands are confined to the volar friction surfaces. Their secretory coils contain sporadically distributed glycogen and phosphorylase and surrounding nerves are much more reactive for acetyl- than butyrylcholinesterase.     

Rating vs. coding in animal personality research

Animal personality research has become increasingly popular over the past few decades. The two main methods used to examine individual differences in animals are rating and coding. The rating method involves human scoring of an animal's behavioral tendencies along various behavioral dimensions, such ratings are typically based on the human rater's experience with the animal. The coding method also requires humans to score an animal's behavior, but differs in that the scoring is based on the animal's immediate behavior in a specific context. This brief report describes the use of both the rating and coding methods to examine personality within a group of 10 Garnett's bushbabies (Otolemur garnettii). The results indicated that individual personalities do exist in bushbabies, but also suggested that the rating method is heavily influenced by the rater's experience with an animal. Consequently, it is important that the nature of the rater's interactions with the target animals be considered when using the rating method to assess animal personality. Zoo Biol 29:509–516, 2010. © 2009 Wiley‐Liss, Inc.     

The skin of primates. 38. The skin of the red uacari (Cacajao rubicundus)

The skin of the red uacari (Cacajao rubicundus) is characterized by distinctive traits. Pigmentation of both the epidermis and dermis in juvenile animals resembles a similar condition recorded in adult Callithricidae. Extensive capillary sinuses pervade the upper dermis of the face, ears, forehead, and frontal scalp. Hederiform nerve endings are common in the face and scalp, as are papillary nerve endorgans in the volar friction surfaces; both are reactive for specific and pseudocholinesterase. A general diminution in size of hair follicles and a retarded generative cycle contribute to the phenomenon of “baldness” in the forehead and scalp of mature animals. Apocrine glands are quantitatively diminished over the dorsum. Eccrine sweat glands, confined to the palmar and plantar friction surfaces, are poorly differentiated; all secretory cells contain glycogen.     

New species of bushbaby from the middle Miocene of Maboko Island, Kenya.

A mandible recovered from ca. 15 million year old deposits of Maboko Island, Kenya, represents the first bushbaby known from the middle Miocene. The specimen is from a new species of Komba, a genus previously known from early Miocene occurrences in western Kenya and northeastern Uganda. Komba is revised, with emended diagnoses proposed for the genus, type-species, and referred species. Komba sp. nov. is distinguished by its larger size and differences of molar cusp acuity, buccal cingulum expression, and mental foramen configuration. Contrary to previous opinion, species of Komba probably diverged prior to the last common ancestor of extant Galaginae, and it is unlikely that they represent early stages of living bushbaby species lineages. Although contemporary Progalago is widely regarded as a galagine, aspects of upper molar, lower premolar, and mandibular corpus morphology indicate that it is more closely related to lorisines. Unlike the greater success currently enjoyed by bushbabies, lorisines were more diverse and almost as abundant as galagines in the early Miocene of eastern Africa.     

The skin of primates. XXXIX. The skin of the white-browed capuchin (Cebus albifrons)

The skin of the white-browed capuchin (Cebus albifrons), although basically similar to that of the squirrel monkey (Saimiri sciureus), contains several outstanding peculiarities: (1) both the epidermis and dermis of the general body surface are devoid of melanotic melanocytes; (2) the skin of the prehensile tail has no modified, glabrous friction surface; (3) the prehensile surface of the tail has no specialized nerve end-organs; (4) cholinesterase-positive, papillary nerve end-organs rest beneath the epidermal ridges of volar skin; and (5) both the clear cells and dark cells of the eccrine glands contain glycogen but neither shows phosphorylase activity.     

Spectral sensitivity and photopigments of a nocturnal prosimian,the bushbaby (Otolemur crassicaudatus)

Earlier studies yielded conflicting conclusions on the types of photoreceptors and photopigments found in the eyes of nocturnal prosimians. In this investigation a noninvasive electrophysiological procedure, electroretinogram flicker photometry, was employed to measure scotopic and photopic spectral sensitivity in the thick-tailed bushbaby (Otolemur crassicaudatus). The scotopic spectral sensitivity function of the bushbaby has a peak of about 507 nm. Under photopic test conditions, spectral sensitivity shifts toward the longer wavelengths. The results from a series of adaptation experiments indicate that the cones of the bushbaby retina contain only a single type of cone photopigment (peak sensitivity at about 545 nm). One implication from this result is that these animals do not have color vision. The photopigment arrangement of the bushbaby is different from that earlier found in diurnal and crepuscular prosimians but is similar to that of the owl monkey, the only nocturnal simian. © 1996 Wiley-Liss, Inc.     

Hopping locomotion in a nematode: Functional anatomy of the caudal gland apparatus of Theristus caudasaliens sp. n.

The interstitial nematode Theristus caudasaliens n. sp. normally locomotes by hopping on the left side of its tail tip, a mode of locomotion that is unique among nematodes. The animal uses its caudal glands and caudal musculature to perform the hops, attaching itself momentarily between hops with the glands and executing the hops by straightening and curling the posterior part of its body. The caudal gland apparatus can be seen by electron microscopy to consist of five gland cells of two different types. Three of these cells, termed viscid glands, are involved in adhesion of the animal to substrates and produce ovoid granules with a central dense band. The other two cells are characterized by smaller, lessdense granules and presumably function in releasing the animal from substrates. The ducts of both gland types extend to the tail tip where they terminate in a common crescent-shaped space. Their secretions are released to the outside through two pores on the left side of the tail tip. There is no spinneret valve in this nematode. The muscles of the tail and of the mid-body region are developed to the same extent. The caudal gland apparatus can be compared with the duo-gland adhesive organs of other interstitial animals, but its homology with either these organs or the caudal glands of other nematodes is uncertain. Theristus caudasaliens is described as a new species.     

The dorsal tail tubercle of Mertensiella caucasica and M. luschani (Amphibia: Salamandridae)

Males of the two species of Mertensiella (M. caucasica and M. luschani) possess a tubercle projecting from the skin of the dorsal tail base, the single morphological character that defines the genus. The dorsal tail tubercle functions during courtship, and its role is similar in both species. The tubercle is inserted into the cloaca of the female during ventral amplexus, shortly before the male deposits a spermatophore. Histological examination, however, revealed that the dorsal tubercles differ structurally between the two species. In M. caucasica, the tubercle consists primarily of elongate mucous glands, with granular glands occurring only at the base. Both mucous and granular glands of the tubercle are larger than those in typical skin. Unlike typical skin, however, mucous glands are larger than granular glands. In M. luschani, mucous glands and granular glands occur throughout the tubercle, and the granular glands are larger than the mucous glands, although both types are larger than those in typical skin. The dorsal tubercles of M. caucasica and M. luschani may not be homologous structures and may have resulted from convergent evolution. J Morphol 232:93–105, 1997. © 1997 Wiley-Liss, Inc.     

The digging behavior and skin differentiations in Heterocephalus glaber

The topography and histology of the skin of the naked mole (Heterocephalus glaber) have been correlated with its behavior. The integument is exceptionally loose, thereby reducing integumentary stresses when the animal is digging and moving in narrow tunnels. It also allows the position of the nasolabial sensory patch to change. This patch is exposed to mechanical stimuli when Heterocephalus moves along the tunnel, but becomes partially shielded by a transient buccal evagination, the formation and function of which are here described. Most of the differentiated patches of the skin lie in the cranial and anogenital regions. The eyes are microphthalmic and nearly completely closed by the nonmobile eyelids; there is no pinna, hair-coat or sweat glands. The epidermis is of variable thickness; in some places it has only one layer of cells. The detached epidermal cells penetrate the dermis irregularly. The epidermis of Heterocephalus is specialized by modifications of its germinative stratum, equivalent to an epidermosis, the syndrome of which consists of reduction of all types of epidermal buddings—pilogenetic and adenogenetic—as well as those which have a mechanical significance.     

Acacia gum and its use by bushbabies,Galago senegalensis (Primates: Lorisidae)

Lesser bushbabies (Galago senegalensis moholi)were studied by radiotracking over a 2-year period (August 1975 to August 1977)at a thornveld study site in the Northern Transvaal, South Africa. It was confirmed that the diet consisted exclusively of plant exudates (gums) and arthropods;available fruits were never eaten. The gums were taken from the trunks and branches of Acaciatrees, particularly from Acacia karroo(the major source), from A. tortilis,and to a small extent from A. nilotica.Chemical analysis shows that gums consist predominantly of carbohydrates and water, with small quantities of fiber, protein, and minerals (notably calcium, magnesium, and potassium). Thus, the gums probably present first and foremost a source of carbohydrate in the diet of the lesser bushbaby, though it seems likely that special mechanisms must exist for digestion of the polymerized pentose and hexose sugars. The calcium content of the gums (approx. 1% by weight) is probably significant in offsetting the low calcium content of the arthropod prey, and their high calcium:phosphorus ratio may well counterbalance the low calcium:phosphorus ratio of the arthropods. The gums are apparently produced largely in response to insect activity. Larvae of beetles (families Cerambycidae,Buprestidae, and Elateridae) and of moths (family Coccidae) bore channels beneath the tree surface, and gum is liberated through apertures made during invasion of the host Acacia.Fly larvae (family Odiniidae) may also develop in the gumfilled cavities. Gum exuding onto the surface is collected by the bushbabies on regular nightly visits, and firm evidence was obtained, in the form of characteristic marks on trap baseboards and certain gum sites, that the toothscraper in the lower jaw is used to scoop away gum from tree surfaces. Foraging for, and feeding upon, gum increased during the winter months, which may be particularly harsh in certain years. In the especially cold winter covered by the study, insect availability was minimal and the lesser bushbabies fed mainly on gum, with some of them reducing their total activity period during the night. Gums are available throughout the year and detailed records indicated no clearcut seasonal pattern of gum production. They are therefore an important yearround food resource for the lesser bushbabies. Feeding on gums has been reported for a wide range of primate species in recent years (especially for various species of the families Cheirogaleidae, Lorisidae, and Callitrichidae), and these plant exudates must now be regarded as an important dietary category within the order Primates.