Description of two new species of Ischyroceridae (Crustacea: Amphipoda) from the coast of Southeastern Brazil Author Valério-Berardo, Maria Teresa Author Souza, Ana Maria Thiago De Author Rodrigues, Carina Waiteman text Zootaxa 2008 1857 55 65 journal article 10.5281/zenodo.183596 9c0bde2f-7d5e-491d-bd59-a6d05c869e35 1175-5326 183596 Notopoma fluminense sp. nov. ( Figs. 3–5 ) Material examined : Holotype , male, 5.0 mm, 22°41’S – 40°20’ W , 758 m , col. N/Pq Oceansatpeg I , VIII/ 2006 , MZUSP 18449; Paratypes : 22°41’S – 40°20’ W , 758 m , col. N/Pq Oceansatpeg I , VIII/2006 , MZUSP 18450, 1 male and 1 female ; 22°41’S – 40°20’ W , 730 m , col. N/Pq Oceansatpeg I , XI/2005 , MZUSP 18451, 1 male and 1 female . Etymology : This species name is derived from the citizens’ names from the type locality, Rio de Janeiro State, Southeastern Brazil . Diagnosis: Antenna 1 about half body length flagellum 0.5 X as long as peduncle, 4-articulate Maxilla 1, outer plate with 5 setae-teeth. Gnathopod 2 male with palmar margin crenulated, ornamented by simple setae, propodus broad, dactylus as long as propodus. Pereopod 7, dactylus with 1 accessory spine. Pleopod 1 and 2 birramous. Pleopod 3 absent. Uropod 1 outer ramus 1.8 X longer than inner ramus. Description: Holotype male 5.0 mm. Head ( Fig. 3 ): rostrum, apically acute length 0.1 X head; lateral cephalic lobe developed with eyes, anteroventral corner acute. Antenna 1 ( Fig. 3 ): about half body length: peduncle article 1 rectangular, produced dorsodistally; flagellum 0.8 X as long as peduncle articles 2–3 combined, 4-articulate, article 1 subequal in length to articles 2–4 combined. Antenna 2 ( Fig. 3 ): subequal in length to antenna 1, articles 4 and 5 subequal in length; flagellum accessory 4-articulate, article 1 2.0 X as long as article 2. Mandible ( Fig. 3 ): Incisor with 5 teeth; lacinia mobilis bearing 2 large cusps; right accessory setal row with 2 robust setae; palp with 5 plumose setae along article 2; article 3 clavate and with 10 plumose setae along inner margin. Maxilla 1 ( Fig. 3 ): inner plate small with short marginal setae; outer plate with 5 robust setae, the shortest ones (2) bifurcate; palp with 4 apical robust setae. Maxilla 2 ( Fig. 3 ): outer plate slightly broader and longer than inner plate; both plates apically setose. Maxilliped ( Fig. 3 ): inner plate subrectangular with 2 apical robust setae and 4 apical simple setae; outer plate ovate distally, apical margin with 4 cusps, 4 robust setae and 3 simple setae; palp, article 2 longest, article 3 setose distally, article 4 short, with 1 medial and 2 apical robust setae. Pereonite 5 larger than others segments of pereon, as long as wide. Coxae 1–4 small, not contiguous, coxae 1–3 wider than deep. FIGURE 3. Notopoma fluminense sp. nov. Holotype, male, 5.0 mm, 22°41’S–40°20’ W, 758 m, col. N/Pq Oceansatpeg I, VIII/2006, MZUSP 18449. Scale bars = 0.1mm, unless indicated otherwise. FIGURE 4. Notopoma fluminense sp. nov. Holotype, male, 5.0 mm, 22°41’S–40°20’ W, 758 m, col. N/Pq Oceansatpeg I, VIII/2006, MZUSP 18449. Scale bars = 0.1mm. FIGURE 5. Notopoma fluminense sp. nov. Holotype, male, 5.0 mm, 22°41’S–40°20’ W, 758 m, col. N/Pq Oceansatpeg I, VIII/2006, MZUSP 18449; Paratype female, 3.0 mm, 22°41’S–40°20’ W, 758 m, col. N/Pq Oceansatpeg I, VIII/2006, MZUSP 18450. Scale bars = 0.1mm. Gnathopod 1 ( Fig. 3 ): subchelate; coxa anterior margin acute, with 1 anterodistal seta; basis slender, smooth and nacked; ischium posterodistal corner with 1 plumose seta; merus with 5 long plumose setae on posterodistal corner; carpus subequal in length to propodus, with plumose setae along posterior margin and 1 simple seta on anterodistal corner; propodus, longer than broad, palm oblique, weakly serrate with plumose setae and simple setae along margin; dactylus, inner margin serrate, with 3 medial setae. Gnathopod 2 ( Fig. 4 ): carpochelate; coxa with 1 anterodistal plumose seta; basis length 1.7 X breadth with 3 robust setae on anterior margin; ischium with 1 plumose seta on posterodistal corner; merus with 2 plumose setae on posterodistal corner; carpus prominent, length 1.1 X breadth, palmar margin with long posterior defining tooth; propodus length 1.4 X breadth, palmar margin crenulated, ornamented by simple setae; dactylus as long as propodus, with 2 setae on posterior margin and 1 plumose seta on anterior margin. Dactyli of pereopods 3–7 directed posteriorly. Pereopod 3 ( Fig. 4 ): basis broad, length 1.8X breadth, anterior margin smooth with 4 plumose setae; ischium with 2 simple setae on posterodistal corner; merus as broad as long, with 1 simple seta on posterodistal corner; carpus with 1 long plumose seta on anterodistal margin, 2 long plumose setae and 2 simple setae along posterior margin; propodus 1.3 X longer than carpus, with 2 plumose setae along posterior margin and 3 simple setae on anterodistal corner; dactylus 0.7 X longer than propodus. Pereopod 4 ( Fig. 4 ): basis subovate, length 1.6 X breadth, with 2 plumose setae along anterior margin; ischium with 1 simple seta on posterior margin; merus longer than broad, with 2 plumose setae on posterodistal corner; carpus with simple and plumose setae on distal corners; propodus length 2.4 x breadth, with 2 plumose setae along posterior margin and 2 simple setae on anterodistal corner; dactylus 0.6 X longer than propodus. Pereopod 5 ( Fig. 4 ): coxa 2X as wide as long, posteriodistal corner rounded; basis quadrate, as long as wide, with 1 seta on anterodistal corner; ischium with 1 simple seta on anterodistal corner; merus with rounded lobes on both distal corners, with 1 plumose seta on posterior lobe and 1 simple seta on anterior lobe; carpus with 1 plumose seta on small posterior lobe; propodus 2.2 X longer than carpus, with 2 simple setae on anterodistal corner and 1 simple seta on posterodistal corner; dactylus short, uncinate with 1 small accessory spine. Pereopod 6 ( Fig. 4 ): basis elongate, length 1.8 X breadth, with 5 robust setae on anterior margin; ischium with 1 simple seta on anterodistal margin; merus longer than broad, with 1 short seta on posterodistal margin and 2 short setae on anterodistal margin; carpus with 1 long plumose seta on posterodistal corner and 2 short plumose setae on anterodistal corner; propodus 1.7 X longer than carpus, with 2 simple setae on anterodistal corner and 1 seta on anterior margin; dactylus short, uncinate, with 1 accessory spine. Pereopod 7 ( Fig. 4 ): similar in form to pereopod 6, but slightly longer. Pleopod 1 ( Fig. 4 ): biramous; rami subequal in length and with long plumose setae; outer ramus broader than inner ramus; inner ramus with 4 articles, outer ramus with 5 articles. Pleopod 2 ( Fig. 4 ): biramous, smaller than pleopod 1; outer ramus broader and longer than inner ramus, bearing long and plumose setae on both margins, with 2 articles; inner ramus 1-articulate, reduced, bearing apical plumose setae;. Pleopod 3 : absent. Urosomite 1 as long as urosomites 2 and 3 combined ( Fig. 3 ). Uropod 1 ( Fig. 5 ): biramous; peduncle and outer ramus subequal in length; outer ramus 1.8 X longer than inner ramus, with lateral row of spines and 1 apical robust pectinate seta; inner ramus with 1 apical pectinate robust seta. Uropod 2 ( Fig. 5 ): uniramous; peduncle 1.7 X longer than ramus; ramus with 1 apical plumose seta. Uropod 3 ( Fig. 5 ): uniramous; peduncle subequal in length to peduncle of uropod 2; ramus vestigial, bearing 2 small curved spines. Telson ( Fig. 5 ): 4 X as long as wide, cleft about 0.3 X of length, with small spines arranged in 1 row on dorsal surface and small setae on distal margin. Female paratype , 3.0 mm: differs from male in gnathopod 2 subchelate. Gnathopod 2 ( Fig. 5 ): carpus posterior margin weakly produced; propodus ovate and broad, palmar margin serrate; dactylus, inner margin serrate, in paratype illustred it is broken. Remarks: When Lowry and Berents (1996) established the genus Notopoma , the number of the setalteeth (7–10) on maxilla 1 outer plate was considered a generic character. But in the re-description of the species Notopoma oppositus (K H Barnard, 1932 ) , Lowry (1981) cited only 6 setal-teeth on outer plate of maxilla 1 and Notopoma fluminense sp. nov. has only 5 setal teeth. These species share with the other 11 species of Notopoma the peduncle article 1 of antenna 1 distally expanded and gnathopod 2 in male carphochelate, certainly the diagnostics characters of the genus, but the number of setal-teeth would not considered as generic character. Notopoma fluminense sp. nov. is closely related with N. stoddartae Lowry and Berents (1996) in having broad propodus of the gnathopods 2 of both sexes, only 1 accessory spine on pereopod 7 dactylus and pleopod 3 absent. But the former can be distinguished by length of antennae (0.3 X body length in N. stoddartae ), number of articles of antennae flagellum and pleopod 2 biramous (uniramous in N. stoddartae ), besides the number of setal teeth on outer plate of maxilla1.