Phtisica marina Slabber, 1769
Caprellid, “Ghost” or “Skeleton” shrimps, so called for their skeletal appearance. Amphipod crustaceans, easily distinguished by the elongate stick-like body form and reduction of the abdominal appendages. Head is generally fused with pereonite 1. Pereopods on first 2 segments (pereonites) are most flexible and called gnathopods; gnathopods 2 being the largest, used in defense, feeding and substrate attachment. In many species pereopods 3 and 4 may also be reduced or absent. Gills on pereonites 3 + 4, rarely on pereonite 2. Pereopods 5 - 7 much smaller than 1 + 2, used for clinging to the substratum. In females, brood plates (öostegites) develop on pereonites 3 + 4. Much remains to be learnt about their biology, ecology and in many cases changing distributions.
Length: 3-25mm. Body smooth. Antenna 1 from ½ to full length of body; antenna 1 approximately equal to antenna 1 peduncle. Gnathopod 1 propodus triangular with 4-5 grasping spines, palm with numerous short spines. Gnathopod 2 carpus shorter than merus, propodus widest proximally with proximal grasping spine and auxilliary spine, palm with numerous short spines and setae. Gills on pereonites 2-4 elliptical, those on 2 being smallest. Pereopods 3 + 4 six-segmented, palm of propodus with 3 short spines; pereopod 5 five-segmented; pereopods 6 + 7 six-segmented with 2 proximal grasping spines, 1 medial spine and 1 distal spine.
Many Synonyms, see McCain 1968 for full list
Ecology and Distribution
Northern Norway to the Mediterranean Sea; British Isles; Azores; Canary Islands; Mediterranean and Black Seas; tropical West Africa; South Africa; Brazil; East coast North America; Virgin Islands; Venezuela; Colombia- Amphi Atlantic.
Surface to 660m. Substrate generalist: green and brown algae, sea grass, sponges, hydroids and bryozoans.
Described as predatory on Caprella acanthifera- grasping the prey with gnathopod 2 and seemingly introducing poison from the poison tooth (Costa 1960).
- Proto pedata (synonym)
- Proto goodsiri (synonym)
- Proto ventricosa (synonym)
- Proto elongata (synonym)
- Phthisica acaudata Reibisch, 1906 (synonym)
- Phtysica marina Crawshay, 1912 (synonym)
- Phtysica acaudata Borcea, 1934 (synonym)
- Phthisica marina Norman, 1886 (synonym)