Difference Between Strepsirhini and Haplorhini

The key difference between Strepsirhini and Haplorhini is that the Strepsirhini has a naked nose whereas the Haplorhini has a furry nose.

Strepsirhini and Haplorhini are two living primate groups. However, these two groups of primates show distinctive characters that differentiate one from the other. Hence, they are in two separate primate groups under the classification of primates. One of the main differences between Strepsirhini and Haplorhini is the morphological features of the nose.

CONTENTS

1. Overview and Key Difference
2. What is Strepsirhini
3. What is Haplorhini
4. Similarities Between Strepsirhini and Haplorhini
5. Side by Side Comparison – Strepsirhini vs Haplorhini in Tabular Form
6. Summary

What is Strepsirhini?

The suborder Strepsirhini consists of organisms which have naked noses and most often a wet nose, which is referred to as the Rhinarium. In addition, the features of Strepsirrhines include the presence of lower incisors which form the toothcomb, large olfactory lobes in the ear, a special layer in the eye which facilitates night vision and a modified hind foot known as the toilet claw. The general dental formula of Strepsirhini is 2,1,3,3.

There are three main infra orders that belong to the suborder Strepsirhini. They are, Lemuriformes, Chiromyiformes and Lorsiformes.

What is Haplorhini?

Haplorhines are dry-nosed primates which have furry noses. They lack a tooth comb and the grooming claw or the toilet claw. The upper lip of Haplorhini does not connect to the rhinarium. This feature enables the flexible facial movements and expression. Based on the physiological features, Haplorhinis can divide into two main groups; Platyrrhini and catarrhini. The infra-order Platyrrhini consists of organisms that have flat noses and an outward directed nostril.

On the contrary, catarrhines have downward directed nostrils. These two groups can also be classified based on their dental formula. The Platyrrhini have a dental formula of 2,1,3,3, whereas catarrhini have a dental formula of 2,1,2,3. Humans also belong to the category of Catarrhini. A characteristic feature of Haplorhini is the inability to produce the terminating enzyme of the Vitamin C synthesis pathway, thus this enzyme cannot be produced within the organism.

What is the Similarity Between Strepsirhini and Haplorhini?

• Both belong to the category of primates.

What is the Difference Between Strepsirhini and Haplorhini?

Strepsirhini and Haplorhini are great primate groups. However, Strepsirrhines are an early primate group with wet, naked noses whereas Haplorhines are modern, evolved primate group with dry, fluffy noses. This is the key difference between Strepsirhini and Haplorhini. But, in addition to this, there are many other differences between Strepsirhini and Haplorhini; such as, the presence of a toothcomb in Strepsirhini and the absence of it in haplorhine. Similarly, Strepsirhini has a grooming claw while Haplorhini doesn’t etc. Furthermore, the subcategories of Strepsirhini are Lemuriformes, Chiromyiformes and Lorsiformes. On the other hand, the subcategories of Haplorhiniare Platyrrhini and Catarrhini.

The below infographic presents more facts on the difference between Strepsirhini and Haplorhini.

Summary – Strepsirhini vs Haplorhini

Primates are a large group of organisms, and upon evolution, they have classified into two broad classes, Strepsirhini and Haplorhini. Strepsirrhines have wet noses and are thought to have evolved first among the primates. The subgroup Haplorhini have dry noses and are thought to have evolved after the Strepsirhinis. Both the groups have distinct morphological features that are used to distinguish between the two groups. This is the difference between Strepsirhini and Haplorhini.

Reference:

1.“Order Primates.” Hylobatidae : Gibbons and Siamangs. Available here  
2.“Order Primates.” Hylobatidae : Gibbons and Siamangs. Available here 

Image Courtesy:

1.”Eulemur mongoz (male – face)”By IParjan – Own work, (Public Domain) via Commons Wikimedia  
2.”Totenkopfaeffchen” (CC BY-SA 2.0 de) via Commons Wikimedia