Taxonomy of Finfish

2.1.5.2 Lips

The premaxillary and maxillary bones of the upper jaw are covered by the upper lip and the mandible on the lower jaw by the lower lip. Mostly these lips are thin smooth membranes but in some theymay be with pores (Fig. 13A), stripes (Fig. 13B) as ni Labeo dero and L. dyocheilus respectively or modified to form a sucker- like disc as in Garro species (Fig. 13 E). In some as in the Mahseer the lower and upper lips are continuous around the jaws and the labial fold (fold formed by the lips) is uninterrupted by the isthmus (Fig. 13 C) or interrupted (Fig. 13D). The lower lip may evenable prolonged as a flap called the mentum. In Tor progenius the upper lip is modified as a fan shaped structure. (Fig. 13 F). Depending upon the position of the mouth the lips may also be terminal or inferior as they are adherent to the jaws.

 Lip Structure

                                                    

Lip

Fig. 13. Lip structure. A. Labeo dero with pores. B. Labeo dyocheilus with stripes. C. Labial fold continuous with metum. D. Labial fold interrupted. (b=Upper lip) E. With a suctorial disc on lower lip Garra. F. Upper lip with fan-shaped enlargement Tor progenius.