PfcREZ FARFANTE: ROCK SHRIMP GENUS SICYONIA 



tral carina, situated distinctly dorsal to ventral 

 margin, strong and extending to end of rostrum. 



Carapace with well-marked postrostral carina 

 bearing three teeth: 1) epigastric tooth small, only 

 slightly larger than first rostral, situated opposite 

 (rarely) to <0.1 cl posterior to orbital margin; 2) 

 middle tooth, larger than epigastric, sharp, placed 

 well posterior to hepatic spine, between 0.33 and 

 0.40 (mean 0.36) cl from orbital margin; and 3) 

 posterior tooth, larger than middle tooth, acutely 

 pointed, rising almost vertically with only apical 

 part inclined anteriorly or so inclined throughout, 

 and situated between 0.70 and 0.77 (mean 0.74) cl 

 from orbital margin; tuft of setae present at an- 

 terior base of all three teeth. Postrostral carina 

 low anterior to middle tooth, high between middle 

 and posterior one, and descending gradually from 

 latter to posterior margin of carapace. Antennal 

 spine relatively long, sharp, and projecting from 

 short buttress; hepatic spine acutely pointed, 

 larger than antennal, arising from moderately 

 raised area between 0.20 and 0.26 (mean 0.22) cl 

 from orbital margin. Postocular sulcus short but 

 deep, continuing as shallow groove; hepatic sulcus 

 well marked; branchiocardiac carina usually low 

 (sometimes barely distinct) but occasionally quite 

 prominent and long, extending to bifurcation near 

 posterior margin of carapace, short branch curv- 

 ing dorsally and longer one ventrally. 



Ocular stylet with terminal part straight or, 

 occasionally, turned laterally. 



Antennular peduncle with stylocerite produced 

 in long spine nearly or quite reaching mesial base 



7 14 21 28 



carapace length (mm) 



35 



Figure 32. — Sicyonia penicillata. Relationship between ros- 

 trum length and carapace length (regression equation, y = 

 0.65537 + 0.13963;c). 



of distolateral spine; latter slender and sharp, ex- 

 tending as far as proximal 0.70 of second antennu- 

 lar article; antennular flagella short, with 

 maximum length of 0.20-0.30 cl, in juveniles and 

 young adults mesial flagellum slightly shorter 

 than lateral one but in larger adults subequal to or 

 slightly longer. 



Scaphocerite reaching distal margin of anten- 

 nular peduncle or overreaching it by no more than 

 0.10 of its own length; lateral rib ending distally in 

 sharp spine distinctly surpassing margin of 

 lamella. Antennal flagellum 2.4-2.7 times cl in 

 young, and as much as 2.0 times in larger adults. 



Third maxilliped stouter than pereopods. Basis 

 and ischium of first pereopod unarmed. 



Abdomen with high dorsomedian carina ex- 

 tending from first through sixth somites, carina on 

 first produced in strong, sharp, anterodorsally di- 

 rected tooth, slightly to considerably larger than 

 posterior tooth on carapace; carina on fifth somite 

 produced in conspicuous tooth, and that on sixth 

 terminating in strong acute one. 



Anterior margin of pleuron of first abdominal 

 somite almost straight; anteroventral extremity of 

 pleuron of first through fourth somites ending in 

 spine, that of first directed anteroventral ly but 

 that of second usually curved posterolaterally, re- 

 sembling strong spines on third and fourth so- 

 mites; posteroventral margin of first through third 

 somites convex, on fourth broadly angular, and on 

 fifth and sixth sharply so and armed with small 

 caudally directed spine. Pleural spination of first 

 four somites barely, if at all, distinct in juveniles, 

 becoming stronger with increasing length of 

 carapace. 



First somite marked by long, anteromedian 

 pleural sulcus converging with united posterior 

 tergal-posteromedian pleural sulci ventrally, dor- 

 sal extremity of tergal reaching anterior margin of 

 somite; posterior pleural sulcus weak, but usually 

 clearly distinct. Second and third somites with 

 anterior and posterior tergal sulci long, almost 

 reaching base of pleuron; anteromedian pleural 

 sulcus deep, continuous with anteroventral de- 

 pression setting off elongate prominence dorsally 

 and ridge posteriorly; posteromedian pleural sul- 

 cus also long, extending anterodorsally subparal- 

 lel to posterior tergal sulcus; shallow posterior 

 pleural sulcus commonly present in both somites. 

 Fourth and fifth somites with anterior tergal and 

 curved, united posterior tergal-posteromedian 

 pleural sulci merging dorsally. Sixth somite 

 marked by arched posteromedian pleural sulcus 

 and bearing longitudinal ridge along base of dor- 



39 



