Diplopterus pulcher Gray, 1831, type locality not specified.
OTHER COMMON NAMES
German: Hechtkopf; Spanish: Cabeza de lucio.
Length 6 in (15 cm). Elongate, with large head and highly protrusible upper jaws. Labyrinth simple. Has separate endoskeletal ossification in front of basihyal, erroneously termed “gular element” by some authors. Caudal fin is rounded, dorsal fin is short with nine to 11 soft rays, anal fin with a median incisure and 18–19 soft rays, pelvic fin with filamentously elongate first soft ray extending to the end of the body. Color is light beige with longitudinal dark brown bands. There are several transverse stripes in the caudal fin that may be broken up into series of spots. A second, undescribed species from Sumatra and Borneo has numerous green iridescent spots along the body.
Malay Peninsula, Sumatra, and Borneo.
Smaller streams with acidic to highly acidic (down to a pH of 3.5) water; often caught among aquatic vegetation.
The pikehead can protrude its upper jaw to about 33% of the head length, which is quite exceptional among teleosts. In captivity usually remains hidden among vegetation, from where it moves slowly toward prey. At a certain distance of around 3.9 in (10 cm), it makes a sudden rapid lunge (with a peak velocity of 150 cm/s-1 and a duration of 0.03 sec.) to surround the prey by protruding its upper jaws and expanding its huge mouth cavity. Suction seems to play only a minor role in capturing the prey.
FEEDING ECOLOGY AND DIET
Appears to feed exclusively on small fishes.
Mouth brooder with male parental care. Male defends territory around spawning site. Displays conspicuous sexually dichromatic coloration only during courtship and spawning. Mating with a reduced spawning clasp takes place at the bottom. All eggs are released during a single spawning bout, sink to the bottom, and are taken up into the male’s mouth. The male mouth broods up to 150 eggs with a diameter of around 0.12 in (3 mm) for about four weeks. Eggs are pear-shaped, with a striking pattern of parallel surface ridges leading toward the micropyle (a preformed opening, the only place where sperm can enter the egg), where the ridges end in a counterclockwise spiral. This unique surface pattern also occurs in the genera Parasphaerichthys, Ctenops, and Sphaerichthys, demonstrating the close relationship of the four groups. Egg surface pattern may represent a sperm guiding device to enhance fertilization success. Upon release from the male’s mouth, young pike-heads already measure 0.6 in (1.5 cm) long.
The species is not threatened or endangered, but may suffer in the future from habitats destruction.
SIGNIFICANCE TO HUMANS
Ornamental fish for specialized hobbyists.
Copyright © 2014 Animalia Life | All rights reserved