Megalorchestia californiana Brandt 1851

How to Distinguish from Similar Species: The large size and distinctive orange or red color of the base of the second antennae make this species unique in our area.

High intertidal zone of wide, fine sandy beaches on the open coast, usually near decaying seaweed. Especially common on beaches backed by dunes.

Geographical Range: Vancouver Island, British Columbia to Laguna Beach, southern California

As with other members of Family Talitridae, this species has a single, distinct, stout, conical or bladelike ramus on uropod 3 which is at least 1/2 as long as the peduncle but does not greatly exceed the length of the telson. The urosome is laterally compressed. The telson is usually thin and cleft, and has more than two spines. Coxae 1-4 are not greatly different in size though wider posteriorly. The eyes are not on prominent lateral lobes. Antenna 1 is shorter than the peduncle of antenna 2. Megalorchestia species have a simple gnathopod 1 with a dactyl longer than article 6 is wide. Pereopod 6 is slightly longer than pereopod 7, and the ramus of uropod 3 does not taper distally. Megalorchestia californiana has a flagellum of antenna 2 not shorter than the peduncle; the bases of the peduncles of the pleopods are greatly expanded to nearly twice the width of their distal ends, the rami of the pleopods are less than half the length of the peduncles, the inner margin of the outer ramus of uropod 2 has spines, the ventral margins of epimera 2-3 each bear several small spines. The body is ivory or gray-white and the antennae are pinkish-orange or reddish in life. The eyes are round and black. Length up to 2.8 cm.

Biology/Natural History: This common species hides in burrows in the sand during the day, then comes out to feed on decaying seaweed at night. They often may move down near the water line to feed but return to burrows the higher beach afterward. They will drown if kept submerged in seawater. Males may fight over burrows near dawn in summer, and have a plug of sand at the entrance. The burrows are up to 30 cm deepJuveniles have orange second antennae, while the antennae of adults are reddish. Juveniles also have a dark dorsal "butterfly" pattern and a dark mid-dorsal line. Before molting, which normally occurs in the burrow, this species becomes opaque white dorsally, and this color spreads rapidly over the rest of the body. The animal twitches violently and splits the exoskeleton transversely between the first and second thoracic segments and longitudinally down both sides above the legs. The animal then lifts the dorsal plates and backs out. It can't jump normally for 24 hours after a molt. The animals mate in their burrows from June to November in central CA. Females carry dark blue eggs which can be seen through their body wall while they are developing. After she releases 10-100 eggs and the male fertilizes them she carries the eggs in her marsupium until they hatch. Predators include many shorebirds, staphylinid beetles, and racoons. Adults often have parasitic mites such as Gammaridacarus brevisternalis on the ventral surface.

Megalorchestia californiana is a species of sand-hopper in the family Talitridae. It was first described in 1851 by the German naturalist Johann Friedrich von Brandt and is the type species of the genus Megalorchestia. It is commonly known as the long-horned beach hopper.

Megalorchestia californiana er en art i slekten Megalorchestia innenfor tangloppefamilien av ordenen Senticaudata, som inngår i gruppen av tanglopper.