Abstract. — A symbiotic nemer- 

 teaii worm found on spiny lobsters 

 is described and compared with other 

 members of the genus Carcinone- 

 mertes. The new species oi Carcino- 

 nemertes has a relatively large basis, 

 stylet, anterior and posterior probos- 

 cis chambers, and a voluminous sem- 

 inal vesicle. In addition, lateral intes- 

 tinal diverticula project anterior to 

 the level of the middle proboscis 

 chamber. These characters distin- 

 guish this species from others in the 

 genus. 



The life-history patterns of sLx spe- 

 cies of Carcinonemertes appear re- 

 lated to the developmental timing of 

 host embryogenesis. Portunid crabs 

 with a short duration of embryogen- 

 esis are infested by the species C. 

 carcinophila and C. mit^iukurii. The 

 worms settle only on mature female 

 hosts: after eclosion the worms mi- 

 grate to the branchial lamellae of the 

 host where they lie dormant until the 

 host oviposits a new clutch. Cancrid 

 and grapsid crabs with an interme- 

 diate duration of embryogenesis are 

 infested by the species C. epialfi and 

 C. errans. The worms settle on both 

 sexes of crabs and are sexually trans- 

 mitted to female hosts. At eclosion, 

 the worms die or regress and mi- 

 grate to the limb axillae. Lithodid 

 crabs and panulirid lobsters with a 

 long duration of embryogenesis are 

 infested by C. regicides and C. wick- 

 hanii. The nemerteans settle on ovig- 

 erous hosts and die or leave the host 

 after eclosion. 



Carcinonemertes wickhami n. sp, 

 (Nemertea), a Symbiotic Egg 

 Predator from the Spiny Lobster 

 Panulirus interruptus in Soutliern 

 California, witli Remarl<s on 

 Symbiont-Host Adaptations 



Jeffrey D. Shields 



Marine Science Institute and Department of Biological Sciences 

 University of California, Santa Barbara. California 93106 

 Present address Department of Parasitology, University of Queensland 

 St Lucia, Brisbane, Queensland 4067. Australia 



Armand M. Kuris 



Marine Science Institute and Department of Biological Sciences 

 University of California, Santa Barbara, California 93106 



Manuscript accepted 13 December 1989. 

 Fishery Bulletin, U.S. 88:279-287: 



Nemerteans of the genus Carcinone- 

 mertes (Kolliker, 1845) are specialized 

 symbionts of decapod crustaceans. 

 Several species of Carcinonemertes 

 eat the eggs of their hosts (Humes 

 1942, Kuris 1978, Wickham 1980, 

 Roe 1984); and this trophic habit may 

 be diagnostic for the genus (Wickham 

 1986, Wickham and Kuris 1988). 

 Three species have been described 

 from the west coast of North Ameri- 

 ca: C. epialti Coe, 1902; C. errans 

 Wickham, 1978; and C. regicides 

 Shields, Wickham, et Kuris, 1989. 

 Nemerteans from the spiny lobster 

 were distinct from these species in 

 both morphology and life history. The 

 nemertean from the spiny lobster 

 represents the undescribed species 

 listed by Wickham and Kuris (1985) 

 for that host. 



Here we describe the egg predator 

 Carcinonemertes wickhami n. sp., 

 from the broods of the spiny lobster 

 Panulirus interruptus (Randall), from 

 southern California. The distinctive 

 morphological characters of the new 

 species are discussed, and aspects of 

 the life history of the new species are 

 presented with those of other mem- 

 bers of the genus. 



Materials 

 and methods 



Spiny lobsters Panulirus interruptus 

 were collected by University of Cali- 

 fornia divers using SCUBA. Lobsters 

 were caught by hand. Pleopods of 

 infested female lobsters were ex- 

 amined macroscopically; those con- 

 taining worms were excised and im- 

 mediately placed in seawater. Nine 

 ovigerous lobsters were examined 

 in 1982, and 10 in 1988. Three of the 

 lobsters collected in 1988 were held 

 for 4-7 days after eclosion (post- 

 ovigerous); they were then dissected 

 and examined for worms. Particular 

 attention was paid to the limb axillae, 

 branchiae, and branchial chambers. 

 Nemerteans found in the broods of 

 lobsters were gently manipulated 

 onto slides for measuring and photo- 

 micrography. Worms were measui'ed 

 with an ocular micrometer in a dis- 

 secting microscope. They were then 

 covered with a coverslip, and various 

 measurements of internal features 

 were taken with an ocular microm- 

 eter in a compound microscope. 

 Hatched nemertean larvae were ex- 

 amined alive. Measurements are in 



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