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

The role of piloerection in primate thermoregulation

The insulating properties of the primate integument are influenced by many factors, including piloerection, which raises the hair and insulates the body by creating motionless air near the skin's surface. The involuntary muscles that control piloerection, the musculi arrectores pilorum (MAP), are mostly absent except on the tail in most strepsirhines, and are entirely absent in tarsiers and some lorisids. The absence of piloerection and the reduced effectiveness of pilary insulation in preventing heat loss affected the evolution of behavior and metabolic thermoregulation in these animals. In lemurs, this situation contributed to the use of positional and social behaviors such as sunning and huddling that help maintain thermal homeostasis during day-night and seasonal temperature cycles. It also contributed in many lemurs and lorises to the evolution of a wide variety of activity patterns and energy-conserving metabolic patterns such as cathemerality, daily torpor, and hibernation. The absence of functional MAP in strepsirhines and tarsiers implies the absence of effective piloerection in early primates, and the reacquisition of whole-body MAP in ancestral anthropoids prior to the separation of platyrrhine and catarrhine lineages. © 2013 S. Karger AG, Basel.

Apocrine Glands in the Eyelid of Primates Contribute to the Ocular Host Defense

Apocrine glands of Moll are regular components of primate eyelids. We studied the distribution and localization of these glands in three different primate species, the common marmoset, the rhesus monkey, and the hamadryas baboon. In addition, we tested the primate glands of Moll with antibodies against antimicrobial proteins, cytoskeletal proteins and the androgen receptor. The glands of Moll differ in abundance and distribution in different monkeys. In the common marmoset, a representative of the New World monkeys, Platyrrhini, the apocrine glands are frequently found at the lid margin and in the overlying epidermis of the lid. In the rhesus monkey and the hamadryas baboon, representatives of Old World monkeys, Catarrhini, apocrine glands are rarer and located predominantly at the margin of the lid. The immunohistochemical analysis indicates the presence of a variety of antimicrobial proteins, e.g. lysozyme, beta-defensin-2, adrenomedullin, lactoferrin, and IgA, in these glands. Interestingly, there are basically no androgen receptors in the nuclei of apocrine glands at the lid margin in all three monkey species. In the common marmoset, however, androgen receptors are found in apocrine glands of the overlying epidermis of the lid. We speculate that the glands of Moll are derived from apocrine glands as found in the skin of the entire body in New World monkeys which developed at the lid margins of higher primates and humans into specialized glands secreting agents of host defense in the eye.

Failure to produce axon reflex-sweating in the volar skin of Japanese monkey (Macaca fuscata) and crab-eating monkey (Macaca irus)

The functional properties of the sweat glands and their innervation in the volar skin of three Japanese monkeys and two crab-eating monkeys were investigated. The sweat glands responded to both cholinomimetic and adrenomimetic agents, the former being highly predominant in the sudorific effect. Spontaneous emotional sweating was strongly or completely inhibited by atropine at 10(-8)-10(-7) g/ml, but not by dihydroergotamine at 10(-5)-10(-4) g/ml. Axon reflex sweating could not be produced by nicotine at 10(-5)-10(-4) g/ml in all of primates tested. The nerve fibers surrounding the sweat glands were histochemically confirmed to contain both acetyl- and butyrylcholinesterase.

Phylogenetic significance of the skin of New World monkeys (order primates, infraorder Platyrrhini)

The combined properties of a given cutaneous system, like other characters classically employed by systematic zoologists, are useful criteria in the assessment of primate taxonomy and phylogeny. From the synthesis of all available data, it is also concluded that (1) the results define a baseline regarding the normal histology and histochemistry of the skin of most genera and many species of New World monkeys; (2) intrageneric and intraspecific subtleties in cutaneous variation exist in primate integument; (3) single and multiple cutaneous traits contribute to the characterization and accurate identification of most levels of taxa within the primate hierarchy; (4) some traits, however, negate recent taxonomic practices, e.g., the familial position of Callimico; (5) basic cutaneous patterns confirm currently accepted concepts of taxonomy and phylogeny; and (6) the various cutaneous signatures of extant platyrrhines record a history of adaptive radiation in isolation, and suggest that the designation of at least two distinct families is warranted.

The skin primates. XLIV. Numerical taxonomy of primate skin

Data on 84 characteristics of the skin of 36 species of primates were extracted from a series of articles describing the histological and histochemical properties of the skin of primates. The data were subjected to a cluster analysis. The results were in reasonably good agreement with orthodox primate taxonomies although some exceptions were apparent. The species clustered into four main groups approximately comparable to Prosimii, Cercopithecoidea, pithecoidea, and Hominoidea are commensurate with standard taxonomic practice. Within the Ceboidea, however, the Atelinae and Alouattinae tend to group with the Hominoidea, Aotus and Saimiri show variable placements, and Callimico groups with the Callithricidae.