52 U.S. NATIONAL MUSEUM BULLETIN 292 



Rostrum shorter than antennal scales, typically with ventral teeth; antennular 

 flagella shorter than antennular peduncle; basis of second pereiopod armed 

 with spine; fourth and fifth pereiopods shorter than third; male with pe- 

 tasma open, without hornlike transverse processes (figs. 7a-d) 2 



2. Lateral rostral grooves reaching little behind posterior rostral tooth on cara- 



pace; male with petasma lacliing pair of conspicuous hoodlike projections 

 curving around distomedian margin (fig. 7d); female with thelycum open, 

 not covered by heavy membranes meeting in midline. 



Penaeus schmitti (p. 54) 



Lateral rostral grooves reaching nearly to posterior margin of carapace; male 



with petasma bearing conspicuous hoodlike projections curving around 



distomedian margin (figs. 7a-c); female with thelycum covered by heavy 



membranes meeting in midline 3 



3. Petasma of male (fig. 7b) with pointed tip of stiff marginal strip projecting 



freely at distomedian end, not attached to surrounding tissue (marginal 

 strip not armed with spinules); membranous covers of thelycum of female 

 produced anteriorly and tightly closed, anterior carina if present not pro- 

 truding in midline Penaeus brasiliensis (p. 53) 



Tip of marginal strip of petasma not projecting freely at distomedian end; 

 membranous covers of thelycum not meeting anteriorly in midline, revealing 

 short longitudinal carina 4 



4. Posterior extensions of lateral rostral grooves narrow, each less than three- 



fourths as wide as median ridge separating them; distal margins of petasma 

 of male unarmed (fig. 7a); anteromedian carina of thelycum of female 



bifurcate anteriorly Penaeus aztecus subtilis (p. 52) 



Posterior extensions of lateral rostral grooves broad, each usually more than 

 three-fourths as wide as and often wider than median ridge; curved distal 

 edge of stiflF marginal strip of petasma of male bearing 2 to 12 small spinules 

 (fig. 7c) ; anteromedian carina of thelycum of female not bifurcate anteriorly. 



Penaeus duorarum notialis (p. 53) 



Genus Penaeus 



1. Penaeus aztecus subtilis Perez Farfante 



Figure 7a 



Penaeus Brasiliensis, var. Aztecus Ives, 1891 [part], p. 190 [type-locality: Vera- 

 cruz, Mexico]. 



Penaeus brasiliensis. — Many authors prior to 1939 [part]. 



Penaeus aztecus. — Burkenroad, 1939 [part], p. 34. — Holthuis, 1959, p. 63, fig. 6b. 



Penaeus aztecus subtilis P^rez Farfante, 1967, p. 87, figs. 2, 3 [type-locality: oflf 

 Punta Gallinas, Departamento de la Guajira, Colombia]. 



Diagnosis. — Lateral rostral grooves reaching nearly to posterior 

 margin of carapace, narrow, each less than three-fourths as wide as 

 median ridge. Rostrum shorter than antennal scales, usually with 

 ventral teeth. Antennular flagella shorter than peduncle. Basis of 

 both first and second pereiopods armed with sharp spine. Fourth and 

 fifth pereiopods shorter than third. Petasma open, with paired, 

 hoodlike distomedian projections; stiff marginal strip unarmed, 

 distomedian tip not projecting from surrounding tissue. Thelycum 

 covered by paired membranes meeting in midhne but gaping auteri- 



