LOWER BEAK
We examined beaks of M. dentata from five individuals (48, 58, 69, 84, 135 mm ML), measurements are taken from three individuals [69, 84, (temperate North Pacific), 135 mm ML (mature male, equatorial Pacific)]. The following characters are taken from Clarke (1986). Means are used usually for measurements for the two smaller of the three and are presented first; data for the larger specimen is presented separately when its values differ greatly from the other two.
- Pigmentation - Normal.
- Pigmentation pattern - See photographs.XXXXX
- (Wing length)/(visible rostral edge) (profile) - 1.72, 2.55
- Height/baseline (profile) - 0.98
- (Length from rostral tip to wing tip projected on baseline)/baseline (profile) - 0.28, 0.39
- (Hood length)/(crest length) (profile) - 0.58
- (Crest length)/baseline (profile) - 0.59
- (Rostral base)/(visible rostral edge) (profile) - 1.05, 1.18
- (Hood length)/(visible rostral edge) (profile) - 0.87, 1.04
- Rostral width ratio [LRL/(length between jaw angles)] - 1.64, 1.17
- Wing angle (= visible jaw angle in profile) - Obtuse.
- Shape of rostral edge - Slight curve; generally no indication of hook.
- Rostrum (profile) - Broad taper.
- Hood distance from crest - Normal to close.
- Crest - Often slightly curved.
- Lateral wall notch - Slight.
- Hood-wing - Broad.
- Hood notch - Shallow.
- Lateral walls to free corner - Well separated with increasing but low divergence from one another.
- Hood midline - Slightly curved.
- Hood surface without prominent longitudinal ridges or grooves.
- Wing fold - Low, rounded but more angled in adult, usually obscures jaw angle in profile.
- Shoulder - Shoulder blades narrow (much deeper than wide), edges project.
- Shoulder groove - Strong
- Jaw angle - Obtuse, without associated step or transparent strip.
- Jaw edge extension without step and with prominent angle point extending well past shoulder padding; jaw edge extension without clear strip between it and shoulder blade.
- Jaw edge in cross-section - Very sharp, less sharp in adult.
- Crest in cross-section - Narrow.
- Lateral wall - Distinct lateral-wall fold capped by solid ridge that usually overhangs base anteriorly, ridge nearly reaches posterior margin of lateral wall; lateral wall fold, with anterior sharp, medial groove and steeply sloping sides, extends to posterior margin of lateral wall.
Figure. Left and right side views of the same lower beak of M. dentata, 69 mm ML, 2.6 mm LRL, immature male, North Pacific, 43°N, 179°W. Photographs by R. Young.
Figure. Left and right side views of the same lower beak of M. dentata, 58 mm ML, 2.2 mm LRL, immature male, North Pacific, 43°N, 179°W. Photographs by R. Young.
Figure. Side views of lower beaks of M. dentata that have been cut in half and laid flat with drawn cross-sections of the lateral wall overlayed where the cuts occurred. Left - 135 mm ML, 2.0 mm LRL, mature male, equatorial Pacific at 06°N, 150°W. Right - 84 mm ML, 3.6 mm LRL, immature female, North Pacific at 43°N, 179°W. Photographs by R. Young.
Figure. Left and right side-oblique views of the same lower beak of M. dentata, 69 mm ML, immature male, North Pacific, 43°N, 179°W. Photographs by R. Young.
Figure. Two views of the same lower beak of M. dentata, 69 mm ML, immature male, North Pacific, 43°N, 179°W. Left - Top view. Right - Posterior-oblique view showing the width of the lateral wall ridge (arrow). Photographs by R. Young.
Figure. Front (left) and rear (right) views of the same lower beak of M. dentata, 69 mm ML, immature male, North Pacific, 43°N, 179°W. Photographs by R. Young.
Comments
To be added.
UPPER BEAK
Figure. Side view of the upper beak of M. dentata, 69 mm ML, immature male, North Pacific, 43°N, 179°W. Photographs by R. Young.
Figure. Various views of the same upper beak of M. dentata, 69 mm ML, immature male, North Pacific, 43°N, 179°W. Left - Top view. Middle - Bottom view. Right - Front view. Photographs by R. Young.
Comments
To be added.
