The pelvic girdle and fin in certain Indian hill stream fishes

Abstract

This paper deals with the functional morphology of the pelvic girdle and fins in various genera of hill stream cyprinid and sisorid fishes. The pelvic plate of Pseudecheneis shows the greatest modification; it is unusually large and reaches the coracoids of the pectoral arch in front. The elaborate working of the pelvic muscles and their function in bringing about effective adhesion by the pelvic fins is described in detail. The formation of a new muscle, M. pars retractor ischii of the M. mesioventralis, is reported in Garra and Psilorhynchus (Cyprinidae) and in Glyptothorax and Pseudecheneis (Sisoridae). In Pseudecheneis, the complete separation of this muscle from the M. mesioventral, and modification of the M. protractor ischii, are discussed in relation to the crawling habit of the genus. The appearance of the M. arrector pel vicalis ventralis in Glyptothorax and Pseudecheneis among sisorids has been associated with the adhesive function of the outer ray.

Comparative anatomy of zebrafish paired and median fin muscles: basis for functional, developmental, and macroevolutionary studies

“…Following this argument, one could also note that pelvic fins lack such a possibility and that their remote posterior position leads to the pelvic girdle being fixed to the body via the hypaxial muscle mass attached to the pleural ribs. In other cyprinid fishes, this connection may be additionally strengthened by a ligament from the seventh pleural rib to the dorsal surface of the pelvic plate (Saxena & Chandy, ). Nevertheless, our comparative data indicate that this difference is not merely a question of topological position.…”

“…Descriptions of these muscles were rather brief and none of the authors specified attachment sites of every pectoral muscle. Muscles of the pelvic fins were described in various actinopterygian fishes (Winterbottom, 1974;Molnar et al 2017), including several derived species of the cyprinid family (Saxena & Chandy, 1966)the family that includes the zebrafishbut they have never been described in adult zebrafishes. Furthermore, the muscles of the anal fin have never been described in adult zebrafishes, and the only description of the dorsal and caudal fin muscles are those given by Schneider & Sulner (2006) in a paper mainly focused on the fin innervation.…”

Pelvic fins in teleosts: structure, function and evolution

“…Some hill‐stream ostariophysan fishes, such as some cyprinids, homalopterine and gastromyzontine loaches, and sisorid and loricariid catfishes, have independently evolved sucking pads or adhesive organs, modifying pelvic‐fin rays that are located posteriorly on the body. These structures serve as friction devices and facilitate station holding in flowing water, along with other adhesive organs, such as the mouth, the pectoral fins or the ventral surface of the body (Saxena & Chandy, 1966; Roberts, 1982; Sawada, 1982; Das & Nag, 2004; Beamish et al , 2008; Schaefer & Provenzano, 2008). As adaptations to perch habitats in mountain streams, homalopterine loaches and sisorids, Pseudecheneis , have developed enlarged pelvic girdles and well‐developed pelvic muscles; in Pseudecheneis , the pelvic girdle reaches the coracoids of the pectoral girdle (Saxena & Chandy, 1966; Sawada, 1982).…”

“…These structures serve as friction devices and facilitate station holding in flowing water, along with other adhesive organs, such as the mouth, the pectoral fins or the ventral surface of the body (Saxena & Chandy, 1966; Roberts, 1982; Sawada, 1982; Das & Nag, 2004; Beamish et al , 2008; Schaefer & Provenzano, 2008). As adaptations to perch habitats in mountain streams, homalopterine loaches and sisorids, Pseudecheneis , have developed enlarged pelvic girdles and well‐developed pelvic muscles; in Pseudecheneis , the pelvic girdle reaches the coracoids of the pectoral girdle (Saxena & Chandy, 1966; Sawada, 1982). Additionally, the cyprinids Garra and Psilorhynchus and the sisorids Glyptothorax and Pseudecheneis have independently generated a new muscle, the pars retractor ischii in obliquues inferioris (mesioventralis) (Saxena & Chandy, 1966).…”

“…As adaptations to perch habitats in mountain streams, homalopterine loaches and sisorids, Pseudecheneis , have developed enlarged pelvic girdles and well‐developed pelvic muscles; in Pseudecheneis , the pelvic girdle reaches the coracoids of the pectoral girdle (Saxena & Chandy, 1966; Sawada, 1982). Additionally, the cyprinids Garra and Psilorhynchus and the sisorids Glyptothorax and Pseudecheneis have independently generated a new muscle, the pars retractor ischii in obliquues inferioris (mesioventralis) (Saxena & Chandy, 1966).…”