Notopoma fluminense, Valério-Berardo, Maria Teresa, Souza, Ana Maria Thiago De & Rodrigues, Carina Waiteman, 2008

Valério-Berardo, Maria Teresa, Souza, Ana Maria Thiago De & Rodrigues, Carina Waiteman, 2008, Description of two new species of Ischyroceridae (Crustacea: Amphipoda) from the coast of Southeastern Brazil, Zootaxa 1857, pp. 55-65 : 60-64

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.

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.

Figures

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 = 0.1 mm, 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 = 0.1 mm.

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 = 0.1 mm.