92 U.S. NATIONAL MUSEUM BULLETIN 25 8 



truncate or slightly excavate posteriorly depending on obliqueness 

 of orientation. 



Type species. — Neomegamphopus roosevelti Shoemaker (1942b). 



Relationship. — This genus mimes Microdeutopus Costa in its 

 male gnathopods but differs in the longer third peduncular article 

 of antenna 1, the equal antennae 1 and 2, the short, truncate third 

 mandibular palp article, the shape and armature of the maxillipedal 

 dactyl, the abbreviated fifth pereopod, the biarticulate outer ramus of 

 uropod 3 which is shorter than the inner ramus, and the shallow 

 telson. It might be confused with Acuminodeutopus J. L. Barnard 

 but differs in the third uropod having an elongated, not reduced 

 inner ramus and by the structure of the third mandibular palp article. 

 In contrast to Microdeutopus both Neomegamphopus and Acuminodeu- 

 topus have less disproportionate antennae and pereopod 5. Neomicro- 

 deutopus Schellenberg has a uniramous third uropod. 



Shoemaker carefully noted the intermixture of aorid and photid 

 (=isaeid) characters of this genus, of which the third mandibular 

 palp article is notably short in resemblance of Megamphopus in the 

 Isaeidae. Despite Shoemaker's assignment of this genus to the Photidae 

 (now Isaeidae), young male first gnathopods are so distinctly aorid 

 that the genus is transferred to the Aoridae. Indeed, aorids and 

 isaeids may not deserve familial separation, especially if the seas 

 hold more species and genera of such character as Neomegamphopus. 



Neomegamphopus roosevelti Shoemaker 



Figures 5-6 



Neomegamphopus roosevelti Shoemaker, 1942b, pp. 36-38, fig. 13. — J. L. 

 Barnard, 1962a, p. 10. 



In the southern Californian intertidal this species has not been 

 found in the fully adult male condition shown by Shoemaker. Its 

 resemblance to Microdeutopus schmitti Shoemaker (1942b) and 

 Acuminodeutopus heteruropus J. L. Barnard (1959) is confusing 

 because young or subterminal males have gnathopod 1 resembling 

 that of those species. Its small size, about 2.0 mm. in length, neces- 

 sitates removal and mounting of the mandible or uropod 3 for identifi- 

 cation according to statements made in the generic diagnosis above. 



Material. — corona del mar: red algae below water, scarce; 

 soft polychaete tubes, rare; tunicate colonies at base of Phyllospadix, 

 scarce; tunicates and soft polychaete tubes, abundant; Laminaria, 

 moderately abundant. 



Distribution. — Cabo San Lucas, Baja California, to Corona 

 del Mar, California, 0-42 m. 



