Euprymna scolopes, Hawaiian bobtail squid

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Euprymna scolopes is a small (to just 35 mm ml) sepiolid squid endemic to the Hawaiian Islands. While nocturnal like other sepiolids, it is unusual in that it ranges into very shallow water just 2-4 cm deep. Most other sepiolids are found in relatively deep water.

E. scolopes can be found at night nearshore over sand flats by wading with a light or lantern or snorkeling with a dive light. During the day it buries itself in the sand. When it emerges from the sand it keeps a "sand coat" on its dorsal surface which is presumed to give it camouflage when attacking prey.
Euprymna scolopes coming out of sand

The sepiolid is relatively short-lived, just 3-10 months from egg to its semelparous death. Eggs are 2.0 mm in diameter and laid on the undersides of coral ledges in shallow water. Paralarvae grow very fast; Hanlon et al. (1997) found E. scolopes to breed and lay eggs in the laboratory just 2 months after hatching from the egg. Juveniles are frequently found with adults in shallow water. Adults are sometimes trawled offshore in mid-water in depths to 138 fathoms. They have been reared in the laboratory on live shrimp in Hawaii and on mysids at Woods Hole.

It has been proposed that E. scolopes can become an easily-reared cephalopod for laboratory research projects. Numerous laboratory studies have been done researching its symbiotic bacterium Vibrio fischeri which lives in the sepiolid's light organ to produce a weak light under the body of the animal. This gives it counter-shading and camouflage from predators.

Ronald R. Holcom's image of a Euprymna scolopes

There are a limited number of studies on the behavior of E. scolopes in the wild, probably because of its nocturnal habits. Anderson and Mather (1996) in describing its escape behaviors said "these large number of unpredictable responses from a nocturnal and small sepiolid such as E. scolopes suggests a high level of neural complexity, perhaps what one might expect from a behaviorally 'advanced' cephalopod mollusc."

References and Credits

References

Anderson, R.C. 1997. Low tide and the burying behavior of Euprymna scolopes (Cephalopoda: Sepiolidae). The Western Society of Malacologists Annual report. 29:12-15.
Anderson, R.C. and J.A. Mather. 1996. Escape responses of Euprymna scolopes Berry, 1911 (Cephalopoda: Sepiolidae). J. Moll. Stud. 62:543-545.
Anderson, R.C. and J.A. Mather. 1997. The shells of Gilligan's Island: common mollusks found around Coconut Island, Oahu, Hawaii. Of Sea and Shore. 20(2):77-82.
Anonymous. 1996. New squid on the block. Science. 272:37.
Arnold, J.M., C.T. Singley, & L.D. Williams-Arnold. 1972. Embryonic development and post-hatching survival of the sepiolid squid Euprymna scolopes under laboratory conditions. The Veliger. 14(4):361-365.
Berry, S.S. 1913. Some new Hawaiian cephalopods. Proceedings of the U.S. National Museum. 45:563-566.
Berry, S.S. 1914. The cephalopods of the Hawaiian Islands. Bulletin of Marine Fisheries, Washington. 30:225-361.
Boettcher, K.J. and E.G. Ruby. 1990. Depressed light emission by symbiotic Vibrio fischeri of the sepiolid squid Euprymna scolopes. J. Bacteriol. 172:3701-3706.
Dunlap, P.V., K. Kita-Tsukamoto, J. Waterbury and S.M. Callahan. 1995. Isolation and characterization of a visibly luminous variant of Vibrio fischeri strain ES114 from the sepiolid squid Euprymna scolopes. Arch. Microbiol. 164:194-202.
Edmondson, C.H. 1946. Reef and shore fauna of Hawaii. Bernice P. BishopMuseum, Special Publication 22. 295 pp.
Gillis, A.M. 1993. Sea dwellers and their sidekicks. BioScience. 43(9):598-602.
Graf, J., P.V. Dunlap and E.G. Ruby. 1993. Effect of transposon-induced motility mutations on colonization of the host light organ by Vibrio fischeri. J. Bacteriol. 176:6986-6991.
Hanlon, R.T., M.F. Claes, S.E. Ashcraft and P.V. Dunlap. 1997. Laboratory culture of the sepiolid squid Euprymna scolopes: a model system for bacteria-animal symbiosis. Biol. Bull. 192:364-374.
Kuo, A., N.V. Blough and P.V. Dunlap. 1994. Multiple N-acyl-homoserinelactone autoinducers of luminescence in the marine symbiotic bacterium Vibrio fischeri. J. Bacteriol. 176:7558-7565.
Kuo, A., S.M. Callahan and P.V. Dunlap. 1996. Modulation of luminescence operon expression by N-octanoyl-homoserine lactone in ainS mutants of Vibrio fischeri. J. Bacteriol. 178:971-976.
McFall-Ngai, M.J. and E.G. Ruby. 1991 Symbiont recognition and subsequent morphogenesis as early events in an animal-bacterial mutualism. Science. 254:1491-1494.
Montgomery, M.K. and M. McFall-Ngai. 1993. Embryonic development of the light organ of the sepiolid squid Euprymna scolopes Berry. Biol. Bull. 184:296-308.
Montgomery, M.K. and M. McFall-Ngai. 1994 Bacterial symbionts induce host organ morphogenesis during early postembryonic development of the squid Euprymna scolopes. Development. 120:1719-1729.
Moynihan, M. 1983. Notes on the behavior of Euprymna scolopes (Cephalopoda: Sepiolidae). Behaviour. 85:25-41.
Nesis, K.N. 1987. Cephalopods of the world. TFH Publications. 351 pp.
Ruby, E.G. and L.M. Asato. 1993. Growth and flagellation of Vibrio fischeri during initiation of the sepiolid squid light organ symbiosis. Arch. Microbiol. 159:160-167.
Ruby, E.G. and M.J. McFall-Ngai. 1992. A squid that glows in the night, development of an animal-bacterial mutualism. J. Bacteriol. 174:4865-4870.
Rummel, J.D. 1996. Squid pro quo? Science. 272:631.
Shears, J.C. 1986. Aspects of feeding in relation to the diel activity pattern of the sepiolid squid Euprymna scolopes. M.S. Thesis. University of Hawaii.
Shears, J. 1988. The use of a sand coat in relation to feeding and dielactivity in the sepiolid squid Euprymna scolopes. Malacologia. 29:121-133.
Singley, C.T. 1982. Histochemistry and fine structure of the ectodermal epithelium of the sepiolid squid Euprymna scolopes. Malacologia. 23(1):177-192
Singley, C.T. 1983. Euprymna scolopes. In: Cephalopod life cycles. Boyle, P.R., ed. Academic Press, pp 69-74.
Wei, S.L. and R.E. Young. 1989. Development of symbiotic bacterial bioluminescence in a nearshore cephalopod, Euprymna scolopes. Mar. Biol. 103:541-546.

Credits

The text and first photograph were provided by Roland Anderson of the Seattle Aquarium. Thanks Roland! Ronald R. Holcom shot the second photograph of a Euprymna in hisaquarium using a Canon AE-1 Program camera with a Soligor zoom+macro 75-250 mm lens. He was keeping the Euprymna for Author/Photographer John P. Hoover, who is working on his third book, a field guide to the marine invertebrates of Hawaii, covering over 500 species. Ron also took photograph of the Euprymna coming out of the sand. No cephalopod page images may be used with out the photographers consent.

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