Caprella angusta Mayer 1903

How to Distinguish from Similar Species: Tritella pilimana has a vestigial pereopod on pereonites 3 and 4, while Caprella angusta does not. Several other members of genus Caprella either do not have the large triangular spine on the dorsal side of the head, or also have large dorsal tubercles on their pereonites and gnathopod 2 is attached near the middle of pereonite 2.

This freeliving caprellid amphipod has gills on only pereonites 3 and 4. It has no pereopods on pereonites 3 and 4. Gnathopod 2 has a propodus which is less than 2/3 as wide as it is long, and the propodus of pereopods 5-7 has only one grasping spine or tooth. There is no spine on the ventral body surface between gnathopods 2, but there is a large, dorsal, anteriorly directed triangular spine on the back of the head. It has few or no tubercles on the dorsal surface of the pereonites, and none on pereonite 1. Gnathopod 2 of the male is attached at the anterior end of pereonite 2.

Biology/Natural History: Caprellid amphipods such as this species are roving predators. We often find them climbing on eelgrass or hydroids searching for prey. With their large claws and bizarre shape they would truly be monsters if they were our size!