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The horn shark is preyed upon by larger fishes and the northern elephant seal (Mirounga angustirostris), which consumes adults, juveniles, and egg cases. In addition, they are captured and eaten by bald eagles (Haliaeetus leucocephalus) at Catalina Island, and large marine snails are able to drill into their egg cases to extract the yolk. [6]
Some egg cases have a fibrous material covering the outside of the egg case, thought to aid in attachment to substrate. [1] [6] Egg cases without a fibrous outer layer can be striated, bumpy, or smooth and glossy. [1] [6] With the exception of bullhead shark eggs, egg cases are typically rectangular in shape with projections, called horns, at ...
The Mexican hornshark (Heterodontus mexicanus) is a bullhead shark of the family Heterodontidae. This shark is grey-brown in color, with black spots scattered on the fins and body. It has a cylindrical trunk, conical head, and small spiracles behind the eyes. The snout of the Mexican hornshark is very round and blunt.
The female Japanese bullhead shark has been known to deposit their eggs in one location along with other females, called a "nest". [8] The egg case of the Mexican hornshark features a tendril and more rigid flanges, suggesting that egg case design of this species primarily involves anchoring with tendrils rather than wedging into crevices. [8]
Some species are oviparous, laying their fertilized eggs in the water. In most oviparous shark species, an egg case with the consistency of leather protects the developing embryo(s). These cases may be corkscrewed into crevices for protection. The egg case is commonly called a mermaid's purse.
Egg case may refer to: Ootheca, an egg case made by some insects and molluscs; Egg case (Chondrichthyes), an egg case made by some sharks, skates, and chimaeras
The egg case of the crested bullhead shark has distinctive, long tendrils at one end. Crested bullhead sharks are oviparous with a possibly annual reproductive cycle. Females produce 10–16 eggs per year during late winter in July and August, though Michael (1993) noted that egg-laying may continue year-round. [1]
Hybodonts laid egg cases, similar to those produced by living cartilaginous fish. Most hybodont egg cases are assigned to the genus Palaeoxyris , which tapers towards both ends, with one end having a tendril which attached to substrate, with the middle section being composed of at least three twisted bands.