A new species of Cheiriphotis (Crustacea: Amphipoda: Corophiidae: Protomedeiinae) from the coast of Southeastern Brazil, with a key to species in the genus Author Valério-Berardo, Maria Teresa Author Souza, Ana Maria Thiago De Author Rodrigues, Carina Waiteman text Zootaxa 2007 1646 41 49 journal article 10.5281/zenodo.179742 dac64f03-abc7-44ff-a1db-b6c49c7a3544 1175-5326 179742 Cheiriphotis neotropicalis sp. nov. ( Figs. 1–4 ) Material examined : holotype , male, 4.5mm , 24°03’S – 46°22’W , 17m , sand bottom, R V W. Besnard col., 29/ VIII/2005 , MZUSP 17222. Paratypes : 2 females , 24°03’S – 46°22’W , 17m , sand bottom, R V W. Besnard col., 29/VIII/2005 , MZUSP 17223; 2 males , 24°03’S – 46°22’W , 17m , sand bottom, R V W. Besnard col., 29/VIII/ 2005 , MZUSP 17224; 2 young males, 24 °03’S – 46°22’W , 17m , sand bottom, R V W. Besnard col., 29/VIII/ 2005 , MZUSP 17225; 2 males , 24°03’S – 46°22’W , 17m , sand bottom, R V W. Besnard col. 29/VIII/2005 , MNRJ 20254;, 2 females , 24°03’S – 46°22’W , 17m , sand bottom, R V W. Besnard col., 29/VIII/2005 , MNRJ 20254. Etymology: The species is named in reference to the latitude region as to where the specimens were collected. Diagnosis : Head with lateral cephalic lobe moderately produced, eyes large. Coxa 1 subtriangular, strongly produced forward with long anterodistal setae. Gnathopod 1 palm acute and excavate, with a serration near of dactylus articulation and slightly elevation at corner of palm, with a robust seta, palm posterior margin with setae. Gnathopod 2, palm transverse, nearly as long as posterior margin of propodus, with three rounded lobes separated by excavations, a strong spine at defining corner of palm to hind margin; dactylus robust and curved, overlapping the palm. Epimera 1–3 rounded, epimeron 2 bearing row of seta on distoventral margin, epimeron 3 larger than the first epimera. Uropod 3 uniramous, peduncle equal to ramus in length and with 1 distal robust seta on inner margin; ramus with 2 robust setae on inner margin and 1distal robust seta, 5 long setae on distal margin. Telson broader than long, with 1 pectinate setae on each distolateral corner, lateral margin naked. Description : Holotype , male 4.5 mm . Head ( Fig. 1 ): slightly shorter than the first 2 body segments; lateral cephalic lobe moderately produced, eyes large. Antenna 1 ( Fig. 1 ): longer than peduncle of antenna 2; peduncular articles 2 and 3 together longer than primary flagellum, peduncular articles in the basidistal ratios 3: 3.6: 2, not strongly setose; primary flagellum 11-articulate; accessory flagellum 3-articulate, with tufts of short setae. Antenna 2 ( Fig. 1 ): article 2 slightly produced ventrodistally, article 4 as long as article 5, flagellum 7-articulate, nearly equal in length to article 5 of peduncle. Mandible ( Fig. 1 ): mandible palp article 1 with 3 inner marginal setae, article 2 longer than article 3, with 6 inner marginal setae, article 3 spatulate, with long distal setae; left incisor with 3 teeth, lacinia mobilis with 3 teeth, with 6 robust setae in the accessory setal row. Maxilla 1 ( Fig. 1 ): inner plate reduced, with an apical plumose seta; outer plate reaching about 2/3 length of palp, with 10 distal setal-teeth; palp 2-articulate, article 2 with 6 distal robust setae and 2 setae on distal margin. Maxilla 2 ( Fig. 1 ): inner plate shorter than outer plate, both plates bearing distal and lateral plumose setae. Maxilliped ( Fig. 1 ): inner plate reaching tip of palp article 1, with a robust seta and 4 simple setae and 3 plumose setae on distal margin; outer plate longer than 2/3 length of palp article 2, with 6 “chisel-shaped” robust setae, 2 robust setae and 2 setae, palp 4-articulate, article 2 of palp longer than articles 3 and 4 combined, article 3 with distal setae. Coxa 1 ( Fig. 1 ): sub-triangular, strongly produced forward with long anterodistal setae; 2nd and 3rd coxae wider than long, with distal plumose setae; 4th coxa longer than wide with distal plumose setae. Gnathopod 1 ( Fig. 1 ): basis slightly inflated distally, posterior margin with 3 long setae; ischium and merus small with long setae on posterodistal corner; carpus slightly shorter than propodus, with long setae on posterior margin; palm acute and excavate, with a serration near of dactylus articulation and with a slight elevation defining palm to hind margin, with a subdistal robust seta, posterior margin with setae; dactylus elongate and slender over 1/2 length of propodus, inner margin serrate. Gnathopod 2 ( Fig. 2 ): basis robust, wider distally; ischium and merus short, subquadrate; carpus completely fused with propodus; propodus enormous, distally wider, subovoid, 1.3X wider than longer, anterior margin with a row of plumose setae; palm transverse, nearly as long as propodus posterior margin, with three rounded lobes separated by excavations, 1 strong spine defining palm to hind margin; dactylus robust and curved, overlapping the palm. FIGURE 1. Cheiriphotis neotropicalis sp. nov. Holotype, male, 4.5mm, 24°03’S–46°22’W, 17m, sand bottom, R/V W. Besnard col., 29/VIII/2005, MZUSP 17222. Pereopods 3 and 4 ( Fig. 2 ): similar in shape but the fourth is larger, both with basis longer than following articles 3–5, anterior margin of basis to carpus with sparse plumose setae; propodus longer than carpus with simple setae on both margins; dactylus short and curved. Pereopod 3 merus with anterodistal margin produced; carpus slender than carpus of pereopod 4. Pereopod 5 ( Fig. 2 ): stout; basis, merus and carpus with plumose setae on both margins; basis as broad as long, shorter in length to following three articles combined; ischium subquadrate; merus slightly longer than carpus; propodus 2 X longer than carpus, posterior margin armed with 4 robust setae; dactylus short and falcate. Pereopods 6 and 7 ( Fig. 2 ): longer and slender than anterior pereopods; basis expanded, posterior margin evenly convex crenulate; basis and merus both margins with plumose setae; merus and carpus subequal in length; propodus longer than carpus, with long setae on posterodistal corner; dactylus slender and curved, ½ in length to propodus. Pereopod 6 propodus anterior margin armed with 4 robust setae. Pereopod 7 longer than pereopod 6, propodus anterior margin with 3 simple setae. FIGURE 2. Cheiriphotis neotropicalis sp. nov. Holotype, male, 4.5mm, 24°03’S–46°22’W, 17m, sand bottom, R/V W. Besnard col., 29/VIII/2005, MZUSP 17222 FIGURE 3. Cheiriphotis neotropicalis sp. nov. Holotype, male, 4.5mm, 24°03’S–46°22’W, 17m, sand bottom, R/V W. Besnard col., 29/VIII/2005, MZUSP 17222; Paratype, female, 4 mm, 24°03’S–46°22’W, 17m, sand bottom, R/V W. Besnard col., 29/VIII/2005, MZUSP 17223. FIGURE 4. Cheiriphotis neotropicalis sp. nov. (a) male, 3.0mm, 24°03’S–46°22’W, 17m, sand bottom, R/V W. Besnard col., 29/VIII/2005; (b) male 3.5mm, 24°03’S–46°22’W, 17m, sand bottom, R/V W. Besnard col., 29/VIII/2005, MZUSP 17225. Epimera ( Fig. 1 ): 1–3 rounded, epimeron 2 bearing row of seta on disto-ventral margin, epimeron 3 larger than the first epimera. Uropod 1 ( Fig. 3 ): extending end of uropods 2 and 3; peduncle longer than rami, posterodorsal margin with comb of 10 robust setae, with marginal and dorsal robust setae; rami subequal in length, both with a notch and a strong robust setae on apical margins; outer ramus with robust setae on dorsal and inner margins; inner ramus with 3 robust setae on inner margin. Uropod 2 ( Fig. 3 ): peduncle slightly longer than rami, outer margin slightly produced apically and with 1 robust seta; rami subequal, both with a strong apical robust seta; inner ramus with 3 robust setae on inner margin; outer ramus with 2 dorsal robust setae and one on outer margin. Uropod 3 ( Fig. 3 ): uniramous, peduncle equal to ramus in length and with 1 distal robust seta on inner margin; ramus with 2 robust setae on inner margin and 1 distal robust seta, 5 long setae on distal margin. Telson ( Fig. 3 ): 1.2X broader than long, with 1 pectinate setae on each distolateral corner, lateral margin naked. Paratype , female 4.0mm: differs from male in gnathopods and uropods. Gnathopod 1 ( Fig. 3 ): palm not excavate, not defined, with a subdistal robust seta, dactylus inner margin serrate. Gnathopod 2 ( Fig. 3 ): larger than gnathopod 1; carpus ½ propodus length, subtriangular; propodus longer than broad; palm acute defined by a spine, with a strong robust seta, a crenulate elevation and excavation in proximal half; dactylus fitting palm. Uropod 3 ( Fig. 3 ): ramus with 3 robust setae on inner margin and 1 robust seta, 2 simple long setae and 2 plumose setae on distal margin. Telson ( Fig. 3 ): with 2–3 simple setae on distolateral corner. Paratype young male 3.5mm : Gnathopod 1 ( Fig. 4 ): palm acute, not defined, dactylus inner margin serrate. Gnathopod 2 ( Fig. 4 ): basis anterior margin with simple setae, propodus 1.3X longer than broad, palm transverse, shorter than propodus hind margin, with 2 small crenulate excavations, defined by a small spine; dactylus curved, fitting palm. Remarks . Among of 13 species described of the genus Cheiriphotis ( Barnard and Karaman 1991 ) , Cheiriphotis neotropicalis n. sp. is closely related to C. mediterranea Myers, 1983 , C. walkeri Stebbing, 1918 and C. williansoni Salman and Jabbar, 1990 . In adult males, these three species have gnathopod 2 carpus vestigial, propodus with transverse palm, and uropod 3 unirramous. However, Cheiriphotis neotropicalis n. sp. can be distinguished from C. mediterranea and C. walkeri by carpus in male gnathopod 1 shorter than propodus, the palm not excavate and with a robust seta at distal half, and by palm in female gnathopod 2 with a sharp spine at defining corner. In addition the former species differs from C. walkeri by strong spine defining the palm of male gnathopod 2 and dactylus overlapping the palm, and also uropod 3 ramus without apical robust seta. Cheiriphotis neotropicalis n. sp can also be distinguished from C. mediterranea by male gnathopod 2 propodus with sub quadrate form, epimeron 3 postero-distal margin naked instead of having a small spine and setae, diagnostic characteristic of C. mediterranea . Cheiriphotis neotropicalis n. sp. is very close to C. williansoni in ornamentation of the palm of gnathopod 2 male and female, but the former species can be distinguished from the latter by the very broad propodus of male adult gnathopod 2, uropod 3 peduncle not expanded distally, telson only 1.3X broader than long instead twice as wide as long in C. williansoni and lacking seate on epimeron 3 ventral margin. Antennae and pereopods 5–7 are described as heavily setose in Cheiriphotis williansoni , a characteristic not observed in the new species. Cheiriphotis neotropicalis n. sp has pereopods 6 and 7 basis with posterior margin crenulate, characteristic not described or illustraded in C. williansoni . Observations of Walker (1904) and Barnard (1962) for Cheiriphotis megacheles ( Giles, 1885 ) suggested that the transformations of palm male gnathopod 2 could be possible by the time the animal grew older. These authors registered for young males, palm acute with small irregularities and with age the palm changed to transverse form and its process sharply pointed. Salman and Jabbar (1990) , refused this observations and described a new species of genus, C. williansoni and considered the adult form of C. megacheles previously registered by Walker (1904) and Nayar (1959 , 1966 ), as a synonym of C. williansoni . Similar with the observations made for Salman and Jabbar (1990) , Cheiriphotis neotropicalis n. sp. not present modification of the male gnathopod 2 palm form, comparing smaller young males and matured males specimens except by less evident spine defining the palm and smaller crenulate excavations.