Ceradocus (Denticeradocus) vaderi, 2019

Alves, Jessika, Johnsson, Rodrigo & Senna, André R., 2019, A new species of Ceradocus Costa, 1853 (Senticaudata: Maeridae) from Ceará State, Northeastern Brazil, Zootaxa 4555 (1), pp. 127-138 : 128-134

Ceradocus (Denticeradocus) vaderi sp. nov.

( Figs 2–7 )

Examined material. Holotype. Male (dissected and drawn) 6 mm, Ceará State, Brazil (1°48'10''S, 39°30'34''W), UFBA 3140 . Allotype. Female (dissected and drawn), 5 mm, Ceará State, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3142 .

Paratypes. Male (dissected) 5.2 mm, Continental shelf, Ceará State, Brazil (1°48’10’’S, 39°30’34’’W) UFBA 3141 . Six females, Ceará State, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3143 .

Etymology. The species is named in honor of Dr. Wim Vader, who contributed much to the knowledge of the family Maeridae .

Diagnosis. Eyes large and ovate. Antenna 1 accessory flagellum 6-articulated. Gnathopod 2 symmetrical in males, palm in lateral view ornamented with two acute processes and large and trapezoid process between the other two. Pereopods 3 to 5 basis ovate with posterior margin serrated. Pereopods 6 and 7 with basis posteriorly expended. Pleonites 2 and 3 dorsally serrated. Epimeral plates 1 and 2 posterior and ventral margins smooth. Epimeral plate 3 posterior margin serrated along its entire length. Telson deeply cleft with apical acute lobes.

Description. (Based on holotype). Head with posteroventral notch, first half of lateral cephalic lobe concave, second half convex ( Fig. 3 ). Eyes large, ovate, slightly expanded ventrally ( Fig. 3 ). Antenna 1, about 1/3 of the body length, peduncular article 1 0.3 times smaller and slightly wider than article 2, accessory flagellum 6- articulated, flagellum 26-articulated ( Fig. 3 ). Antenna 2, cone gland robust, reaching the end of article 3, peduncular article 4 slightly longer than article 5, flagellum 8-articulated, 1.4 times longer than article 5 ( Fig. 3 ).

Lower lip, inner plate ovate bearing apical small setae, outer plate laterally expanded with sparse apical setae ( Fig. 4 ). Mandibular palp 3-articulated, article 1 slender and slightly smaller than article 2, article 2 subrectangular and 1.7 times longer than article 3, article 2 apically rounded with long and slender apical setae ( Fig. 4 ). Molar produced and triturative, left molar with a plumose seta, incisor with two cusps, lacinia mobilis apically rounded with 3 cusps, accessory blades composed by eight slender and simple setae ( Fig. 4 ). Maxilla 1, inner plate rounded with dense apical row of setae, outer plate subrectangular, apically broad with five pectinate setae and five stout simple setae, palp 2-articulated, second article 2.6 times as long as article 1 with slender setae ( Fig. 4 ). Maxilla 2, inner plate subequal in length to outer plate with apical dense row of slender setae ( Fig. 4 ). Maxilliped, inner plate apically rounded, with 18 stout simple setae, outer plate bearing inner and apical margins with pectinate and simple stout setae and exceeding distal end of article 2, palp 4-articulated, article 2, 2.5 times longer than the following article, article 3 longer than dactylus, which bears three apical long setae ( Fig. 4 ).

Coxa 1, anteroventral corner produced and acute, anterior margin accentually convex, ventral margin with one seta, posterior margin slightly convex ( Fig. 5 ). Gnathopod 1 smaller than gnathopod 2; basis posterior margin of with long slender setae, ischium smaller than merus; merus with ventral margin rounded and posterior margin setose; carpus 1.4 times longer than merus and showing posterior margin densely setose, propodus 0.3 times longer than carpus, subquadrate, palm oblique, smooth, with long and stout setae, dactylus long and stout ( Fig. 5 ). Gnathopod 2, coxa subquadrate; basis long and posteriorly enlarged; ventral margin of ischium with broad indent; merus subrectangular, 1.7 times longer than ischium, ventral margin convex, anteroventral corner acute; carpus 2.6 times the length of propodus, posterior margin with slender long setae; propodus long and wide, palm oblique, weakly convex with long and small setae in medial view, presenting two acute processes and trapezoid projection in lateral view, palmar corner defined by soft spine ( Fig. 5 ). Pereopod 3, basis slender, merus slightly longer and larger than carpus; carpus similar to propodus, dactylus stout, nail present ( Fig. 5 ). Pereopod 4, similar to pereopod 3 ( Fig. 5 ). Pereopod 5, basis ovate, anterior and posterior margins slightly undulated with small setae; merus wider and slightly smaller than carpus; carpus half the length of propodus, dorsal margin longer than ventral one; propodus slender with long slender setae, dactylus slender, nail present ( Fig. 6 ). Pereopod 6, basis posterior margin lightly undulated with small setae, anteroventral corner acute, merus stout and smaller than carpus; carpus about 1.2 times longer than merus, subrectangular and twice stouter than propodus; propodus slightly longer than carpus, dactylus slender with dactylar unguis ( Fig. 6 ). Pereopod 7, basis ovate, expanded, in dentate prosteroventral corner with small setae; merus and carpus similar in length and width; propodus subrectangular, wider and longer than carpus; dactylus long and stout with dactylar unguis ( Fig. 6 ).

Pleonite 1 without dorsal spines ( Fig. 3 ). Pleonite 2 with small spines mediodorsally ( Fig. 3 ). Pleonite 3 with large spines mediodorsally ( Fig. 3 ). Epimeral plate 1 rounded, smooth with sparse setae ( Fig. 3 ). Epimeral plate 2 with sparse setae, serrated corner posteroventrally ( Fig. 3 ). Epimeral plate 3, posterior margin rounded and strongly serrated; ventral margin with sparse setae ( Fig. 3 ). Uropod 1, peduncle slightly longer than rami, basofacial seta well developed, distal margin with long and stout spur; inner and outer rami subequal in length; outer ramus with long slender setae in dorsal and ventral margins and four stout setae distally; inner ramus with long and slender setae on lateral margins and two stout setae distally ( Fig. 6 ). Uropod 2, peduncle slightly shorter than rami, inner and outer rami subequal in length with slender setae on ventral and dorsal margins and stout setae on apical margin ( Fig. 6 ). Uropod 3 missing in both male specimens ( Fig. 6 ). Telson 1.7 times wider than long, deeply cleft (about 74%), apical lobes slightly concave with acute cusp, each lobe with two long and one small stout seta ( Fig. 6 ).

Female (sexual dimorphic characters). Based on allotype. Gnathopod 1 smaller than gnathopod 2, coxa 1 with anteroventral corner produced and acute, anterior margin accentually convex, posterior margin slightly convex, basis posterior margin with one long slender seta; carpus subequal in length to propodus, subrounded, with sets of small setae; propodus palm smooth and convex, beset with setae; dactylus without dense setae ( Fig. 7 ). Gnathopod 2 coxa subquadrate with rounded corners; basis long and thin; carpus shorter than propodus, ventral margin broad and rounded beset with long setae; propodus 1.6 times the length of the carpus long and wide, palm oblique, weakly excavated, beset with small setae, without acute processes ( Fig. 7 ).

Type locality. Off Ceará State coast (1°48’10’’S, 39°30’34’’W), Brazil.

Remarks. Ceradocus vaderi sp. nov. differs from the Atlantic species C. shoemakeri Fox, 1973 and C. breweri ( Kunkel, 1910) in having: (1) epimeral plate 3 serrated; (2) palm of gnathopod 2 oblique; and (3) accessory flagellum with less than 10 segments. Nevertheless, C. vaderi sp. nov. differs from both species in having: ovate eyes; two acute and one trapezoid process on palm of gnathopod 2; epimeral plate 3 with ventral and dorsal posterior margins serrate and apical lobes with acute cusps on telson. Ceradocus vaderi sp. nov. also differs from C. paucidentatus , recorded to Brazil, in having: (1) ovate eyes; (2) symmetric gnathopods; (3) male gnathopod 2 palm without distal broad excavation; (4) ventral and dorsal posterior margins of epimeral plate 3 serrate.

The new species also differs from other species of Denticeradocus subgenus: C. ramsay , C. koreanus and C. circe by presenting antenna 1 accessory flagellum 6-articulated. Ceradocus vaderi sp. nov. is unique into Denticeradocus subgenus by presenting male gnathopod 2 symmetrical and propodus palm with two acute and one trapezoid process.

Figures

FIGURE 2. Ceradocus vaderi sp. nov.; Holotype, 6 mm, Adult Male, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3140. Scale Bar: 1 mm.

FIGURE 3. Ceradocus vaderi sp. nov.; Holotype, 6 mm, Adult Male, Ceará State, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3140. Scale Bars: A1–2 (0.5mm); H (0.8 mm); Ep 1–3 (1.0 mm).

FIGURE 4. Ceradocus vaderi sp. nov.; Holotype, 6 mm, Adult Male, Ceará State, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3140. Scale Bars: Mp, Mx2, lMd (0.5 mm). Paratype, 5.2 mm, Adult Male, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3141. Scale Bars: rMd, Mx1, LL (0.5 mm).

FIGURE 5. Ceradocus vaderi sp. nov.; Holotype, 6 mm, Adult Male, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3140. Scale Bar: Gn1, Gn2 (1.0 mm), P3–4 (0.5 mm).

FIGURE 6. Ceradocus vaderi sp. nov.; Holotype, 6 mm, Adult Male, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3140. Scale Bar: 1.0 mm

FIGURE 7. Ceradocus vaderi sp. nov.; Allotype, 5 mm, Female, Ceará Coast, Brazil (1°48’10’’S, 39°30’34’’W), UFBA 3142. Scale Bar: 1.0 mm