P6REZ FARFANTE: ROCK SHRIMP GENUS SICYONIA 



Figure 26.— Sicyonia disedwardsi (Burkenroad 1934),? 34 mm cl, Golfo de Panama, Panama. Lateral view. Scale = 10 mm. 



Description. — Body robust (Fig. 26). Carapace 

 studded with long setae anterior to hepatic spine 

 and in pterygostomian region; patches of densely 

 set shorter setae present on dorsum, in depression 

 anterior to posterodorsal part of branchiocardiac 

 carina, on branchiostegite, and subjacent to hepat- 

 ic sulcus; patches also on tergum of abdominal 

 somites and in depression just ventral to dorsal 

 ridge of sixth somite. Abdomen bearing numerous 

 tubercles on all somites (especially first three), 

 except few or none on sixth. 



Rostrum short, reaching distal margin of eye at 

 most, its length increasing linearly with carapace 

 length (Fig. 27) to about 20 mm cl, then growing 

 little, not surpassing 6 mm (proportional length 

 decreasing with increasing size from as much as 

 0.43 to as little as 0.13 cl); subhorizontal or up- 

 turned to as much as 45° (in young), tapering con- 

 siderably from base to truncate, sometimes de- 

 curved tip; armed with two dorsal and two (96%) or 

 three (4%) apical teeth. Adrostral carina, situated 

 close to ventral margin, extending to end of ros- 

 trum. 



Carapace with well-marked postrostral carina 

 bearing three teeth: 1) epigastric small, only 

 slightly larger than first rostral, situated from 

 slightly anterior to orbital margin to 0.07 cl be- 

 hind it; 2) middle tooth, larger than epigastric, 

 placed well posterior to hepatic spine, between 



0.29 and 0.38 (mean 0.33) cl from orbital margin; 

 and 3) posterior tooth, larger than middle one, 

 acutely pointed (usually abraded in larger adults), 

 rising almost vertically before turning anteriorly 

 or, more often, strongly inclined anteriorly, and 

 situated between 0.68 and 0.80 (mean 0.72) cl from 

 orbital margin; tuft of setae present at anterior 

 base of all three teeth. Postrostral carina increas- 



7 14 21 



carapace length (mm) 



Figure 27. — Sicyonia disedwardsi. Relationship between ros- 

 trum length and carapace length (regression equation for speci- 

 mens with about 20 mm cl or less, y = 0.74318 + 0.2174aac; 

 regression equation for those larger, y = 3.81074 + 0.04939x). 



33 



