Microscopic aspects from howler monkey's (Alouatta fusca clamitans) lip

Abstract

The Howler Monkey (Alouatta fusca clamitans) is one of the three species of prim ates found at Rio Grande do Sul state. It is an herbivorous specie, with diet composed by fruits, leafs, seeds and flowers. The wild animals literature, specially that from brazilian wildlife, is very limited. The aim of this article is to characterize the histologyc composition of the Howler Monkey's lip. An adult, male Howler Monkey that died naturally was used to do the histologiyc study. Were collected peaces of 1 cm³ from the upper lip and subsequently put in a 10% tamponade formol solution. This material was processed by histologyc methods with the inclusion being made in paraffin and was used Hematoxilin-Eosine, Goldner and Mallory as colouring techinques. The Howler Monkey's histologyc structure is similar of that from domestic animals. The skin shows structures like typical glands and pilous follicle, and tactile follicles are present. The dermic free surface has no glands or pilous follicle. Like the free surface, the lip mucosa has a keratinized pavimentous stratified epithelium, with the keratin being a consequence of its rough diet. Mucous glands are found at the lip submucosa layer, being similar from those mucous glands from carnivorous and small domestic ruminants, but are diferent from those glands found at the human lip. Colagenous fibers predominate at the papillary derm of the skin and at the lip lâmina propria mucosae. Despite of being a primate, the glands from Howler Monkey's lip are different from human beings, and unlike human, keratinization is present.