Sergestidae Dana 1852

Sergestes robustus, spined variety, station 4041 (1). Seyllarus martensi, female, station 3872 (2)

Zoea larva of a species of Sergestes, taken by the 'Challenger' Expedition.

All Biocode files are based on field identifications to the best of the researcher’s ability at the time.

based on the right angle bend in the antenna and the coloration, I'd say this is a sergestid

This closeup of the side of the carapace shows the dendrobranchiate (branching like a feather) gills underneath. This gill pattern is characteristic of dendrobranchiate decapods such as Penaeids but is not seen in true shrimp or in crabs.

As in most seregestids, the rostrum is very short. Unlike Eusergestes similis, the rostrum of Sergia tenuiremis is blunt. There are no supreaorbital or hepatic spines on the carapace.

Unlike Eusergestes similis, there is a tubercle on the medial eyestalks in Sergia tenuiremis. In this view the animal is facing left.

Sergia tenuiremis captured below 500 m depth off Point Conception, CA, Sept 1992. This photo is of a preserved specimen which has lost its darker original color. The animal has also lost its long, fragile second antennae which are longer than the body. (Photo by: Dave Cowles Oct 2006)

Most of this species' body is transparent, with small red chromatophore spots. The internal thoracic organs are opaque red or black. The organs of Pesta (not readily visible in this photo) are ventral to the dark thoracic organs. Note the tiny rostrum (the small red dorsal bump behind the eyes). The long second antennae trail out to the right of this photo. Swimming is almost exclusively by the pleopods. Photo by Dave Cowles For an .mpg video of this species swimming in a swim tunnel, click Here (8 megabytes). Note in the video (and in the image at the top of this page, which was taken from the video), that the animal turns downward when exposed to the light of the camera. This is because it is a vertical migrator.

Eusergestes similis can be distinguished from Sergia tenuiremis by the small, acute, upward-pointed rostrum and by the presence of a supraorbital and a hepatic spine. This photo is of a preserved individual.

The epimera of abdominal segment 2 does not overlap those of segments 1 and 3, showing this species is not a Caridean shrimp. Photo from a preserved specimen

The telson is shorter than the uropods, and both telson and uropods are fringed with setae. Photo from a preserved specimen

Eusergestes similis, captured off Point Conception, CA May 1996. Photographed live swimming in a swim tunnel. Total length approximately 6 cm. (Photo by: Dave Cowles, May 1996)

Scale: 1 cm

Scale: 5 mm

Scale: 5 mm

Scale: 1 cm