190 U.S. NATIONAL MUSEUM BULLETIN 258 



Lysianassa pariter, new species 



Figures 50, 51 



Diagnosis. — Epistome lamellar, produced forward as keel nearly 

 as far as rather short plate of upper lip, notch between epistome 

 and upper lip deep; mandibular palp attached well proximal of small 

 setulose molar; inner plate of maxilla 1 slender, acute, with one seta 

 attached sub terminally, outer plate with primary set of 7 serrated 

 spines and secondary set of 4 small serrated to bifid spines; plates 

 of maxilla 2 subequal in width; maxillipedal palp greatly exceeding 

 outer plate, article 4 of normal dimensions; gnathopod 2 chelate; 

 pereopods 1-2 lacking large distal spine on article 6; pereopods 3-5 

 short, each of articles 4-6 much shorter than in L. dissimilis (Stout), 

 posterior and ventral margins of expanded plate of article 2 merging 

 uniformly, ventral edge bearing several setae, fourth articles of 

 medium to poor expansion, fifth articles about two thirds to three 

 quarters as long as sixth; pleonal epimeron 1 rounded at postero- 

 ventral corner, epimeron 2 with small tooth, epimeron 3 produced 

 posteriorly as subquadrate plate; inner ramus of uropod 2 with 

 marginal constriction; peduncle of uropod 3 expanded enormously as 

 lamellifrom plate, outer ramus shorter than peduncle, uniarticulate, 

 bearing 2 (1 in juveniles) stout spines, inner ramus slightly more than 

 half as long as outer ramus, bearing one marginal spine; overall 

 surface area of inner ramus about one fifth that of outer ramus, thus 

 being unusually small; telson entire, apically truncate. 



Holotype. — AHF No. 621, male, 5.7 mm. 



Type locality. — Station 43-E-3, Cayucos, California, in dendritic 

 sponge under rock, January 5-6, 1962. 



Relationship. — This species differs from Lysianassa dissimilis 

 (Stout) (see Shoemaker, 1942b) by the uniarticulate outer ramus of 

 uropod 3, the very short inner ramus, the more strongly expanded 

 peduncle of uropod 3, the shorter pereopods with shorter articles, the 

 lack of a sinus on the posteroventral margin of article 2 of pereopod 5, 

 the presence of setae on the ventral edge of that article and the smaller 

 secondary spines on the outer plate of maxilla 1. 



Lysianassa pariter is not referrable to Nannonyx Sars, despite its 

 reduced inner ramus of uropod 3 because of the lamellar and produced 

 prebuccal parts bearing a dividing sinus. The species forms a perfect 

 intergrade from Lysianassa to the type Parawaldeckia thomsoni Stebbing, 

 the latter having an inner ramus of uropod 3 reduced to one third the 

 length of the outer. 



Material. — cayucos: nodose pink tunicate under rocks, abundant; 

 sponge under same rock, rare, la jolla : tunicate and sponge scrapings 

 under platform, rare. 



Distribution. — Cayucos to La Jolla, California. 



