Ceradocus ( Denticeradocus ), 1939

Ceradocus ( Denticeradocus) View in CoL sp.

( Fig. 5–6 View FIGURE 5 View FIGURE 6 )

Material examined.

One specimen ( UERJ 2302 ), female, 9 mm, dissected and illustrated, 16 m depth, using trap, V/2016, Marine State Park of Laje de Santos ( 24º19’13” S, 46º10’49” W), São Paulo State, Brazil GoogleMaps .

Description.

Mandible, incisor with two cusps; lacinia mobilis multi-cuspidate; accessory setal row with four curved serrate setae and four simple setae; palp, distal margin of article 1 with acute projection, palp article length ratio 1:1.6:0.7. including projection of article 1. Gnathopod 2, coxa subrectangular, ventral margin setose; basis about 2.6× longer than wide, posterior margin setose; merus with acute posterodistal projection; carpus subtriangular, posterior margin with 7 rows of slender setae; 1.4× longer than wide; propodus suboval, 1.9× longer than wide and 1.8× longer than carpus, posterior margin densely setose, palm acute defined by 2 robust setae, minutely serrate near dactylus articulation, with numerous robust setae; dactylus stout, outer margin with a single slender setae, inner margin with setules, apical nail absent. Pereopod 3, coxa subquadrate, ventral margin setose; basis posterior margin densely setose; merus, carpus and propodus length ratio 1:0.7:0.7; carpus and propodus, posterior margins with numerous robust setae; dactylus simple, apical nail present. Pereopod 4 similar to pereopod 3. Pereopod 5, coxa, anteroventral lobe produced, round with setules; basis about 1.7× longer than wide, posterior margin serrate, posterodistal corner acutely projected; merus about 2.2× longer than wide; carpus and propodus subequal in length, anterior and posterior margins with numerous clusters of robust setae; dactylus simple, apical nail present. Pereopod 6, coxa, anteroventral lobe weakly produced, bearing two robust setae; basis about 1.6× longer than wide, posterior margin serrate, posterodistal corner acutely projected; merus about 2× longer than wide; carpus and propodus subequal in length, anterior and posterior margins with numerous clusters of robust setae; dactylus simple, apical nail present. Pereopod 7, coxa with 1 anteroventral seta; basis about 1.6× longer than wide, posterior margin serrate, posterodistal corner acutely projected; merus about 1.8× longer than wide; carpus and propodus subequal in length, anterior and posterior margins with numerous clusters of robust setae; dactylus simple, apical nail present. Pleonites 1–3 dorsal margins distinctively serrate. Epimeral plate 1 ventral margin naked except for a single spine, posteroventral corner weakly produced, acute. Epimeral plate 2, ventral margin with a single spine and 2 robust setae, posteroventral corner produced upwards. Epimeral plate 3, ventral margin with 3 robust setae, ventral and posterior margins serrate. Urosomites 1–2 dorsally serrate. Telson deeply cleft (71% of telson length), each lobe distally acute, with 2 subapical long robust setae.

Remarks.

Although the collected specimen was single, female and partially damaged, it was possible to be classified as a member of the subgenus Ceradocus ( Denticeradocus) , based on typical diagnostic features, such as mandible palp article 1 with acute distal projection, article 3 very short, not falcate; pereopods, dactyli simple; pleonites and urosomites dorsally serrate; posterior margin of epimeral plate 3 strongly serrate. It is also possible to state that this specimen differs from the Brazilian species C. ( D.) vaderi by the following characters (characters in C. ( D.) vaderi in parentheses): gnathopod 2, propodus, palm not excavated (excavated), defined by two robust setae (defined by palmar corner), palmar margin minutely serrate near dactylus articulation (smooth); pereopods 3–4, basis, posterior margin densely setose (weakly setose); pereopods 5–6, basis, posterior margin serrate (smooth), posterodistal corner acutely projected (rounded); pleonite 1 dorsally serrate (smooth); epimeral plate 3, ventral and posterior margins serrate (only posterior margin serrate).

Among the few female specimens documented in the literature, this specimen resembles C. ( D) circe Lowry & Springthorpe, 2005 from Australia, and C. ( D) greeni Appadoo & Myers, 2005 from Mauritius for presenting pereopods 3–4, basis, posterior margin with many long slender setae; pereopods 5–7, basis, posterodistal corner acutely projected; epimeral plates 1–3 ventral margin with 1 or 2 spines; telson lobes strongly acute. However, this specimen can be distinguished from C. ( D) circe by the following characters (characters in C. ( D) circe in parentheses):gnathopod 2, merus with acute posterodistal projection (without acute projection); propodus 1.9× longer than wide and 1.8× longer than carpus (1.75× and 2.6×), palm without excavation (with medial excavation), defined by 2 robust setae (defined by 1 spine); telson, each lobe with 2 long robust setae (4). It can also be differentiated from C. ( D) greeni by (characters in C. ( D) greeni in parentheses): mandible palp articles length ratio 1:1.6:0.7 (1:2:0.4), including projection of article 1; gnathopod 2, carpus posterior margin with 7 rows of slender setae (4 rows); propodus 1.9× longer than wide and 1.8× longer than carpus (2.2× and 1.5×), posterior margin densely setose (weakly setose); pereopod 5 carpus and propodus subequal in length (carpus 1.3× longer than propodus), anterior and posterior margins with numerous clusters of robust setae (few clusters); telson, each lobe with 2 long robust setae (1).

To identify the Ceradocus species, morphological characteristics of the adult males are very important ( Krapp-Schickel & Vader 2009), and identification to the specific level was not feasible in this study. Further sampling of the male specimens is necessary for the accurate identification.