Table 2 Main subdivisions of facial musculature in Actinopterygii
From: Evolution of the facial musculature in basal ray-finned fishes
Muscle | Subdivision | Additional features |
|---|---|---|
MANDIBULAR MUSCLE PRIMORDIUM | ||
1. Constrictor mandibularis dorsalis | 1. Dorsomedial | Origin on lateral region of otic-sphenoidal portion of neurocranium; insertion on lateral face of palatoquadrate, hyomandibula, and opercle (except acipenseriforms) |
1.1. Levator arcus palatini | 1.1. Anterior | Insertion on lateral face of suspensorium, usually on hyomandibula and metapterygoid |
1.2. Dilatator operculi | 1.2. Middle | Insertion on anterodorsal region of opercle |
1.3. Spiracularis | 1.3. Posterior | Insertion on spiracular canal or ossicles; lost or undifferentiated from dilatator operculi in neopterygians |
2. Adductor mandibulae | 2. Ventrolateral | Origin on lateral region of palatoquadrate and, often, hyomandibula and neurocranium; insertion on lower jaw; additional attachments to maxilla in Amia and several teleosts |
2.1. Segmentum facialis | 2.1. Dorsolateral | Larger and most superficial division on cheek |
2.1.1. Pars rictalis | 2.1.1. Ventrolateral | Origin on ventroposterior region of suspensorium, usually involving quadrate |
2.1.2. Pars malaris | 2.1.2. Dorsolateral | Origin on dorsoposterior region of suspensorium, usually involving hyomandibula |
2.1.3. Pars stegalis | 2.1.3. Medial | Shorter fibers with origin on anterior region of suspensorium, usually involving metapterygoid |
2.2. Segmentum buccalis | 2.2. Dorsomedial | Deeper division on cheek; lost in teleosts |
2.2.1. Pars orbitalis | 2.2.1. Anterior | Located just posterior or anteroventral to eyeball |
2.2.2. Pars sphenoidalis | 2.2.2. Posterior | Origin medial to levator arcus palatini |
2.3. Segmentum mandibularis | 2.3. Ventral | Fully or mostly concealed laterally by lower jaw |
HYOID MUSCLE PRIMORDIUM | ||
3. Constrictor hyoideus dorsalis | 3. Dorsal | Origin on lateral region of otic-temporal region of neurocranium; insertion on medial faces of palatoquadrate, hyomandibula, and opercle |
3.1. Adductor hyomandibulae | 3.1. Anterior | Insertion on hyomandibula and, often, metapterygoid and endopterygoid |
3.2. Adductor operculi | 3.2. Middle | Insertion on the anterior region of opercle, near its articulation with hyomandibula; associated with medial crest of opercle in teleosts. |
3.3. Levator operculi | 3.3. Posterior | Narrow origin via elongate tendon/aponeurosis; broader insertion on posterior portion of opercle |