taxonID	type	description	language	source
03A012206C048077D033FB8E961DFAC7.taxon	diagnosis	Diagnosis. Mouth parts styliform. Mandible incisor styliform, molar absent. Coxa 1 reduced and partially covered by coxa 2. Gnathopod 1 strongly subchelate and robust; propodus inverted in adult stage; palm with stout setae; dactylus large. Telson small, entire or cleft (modified from Barnard & Karaman, 1991).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C048077D033FB8E961DFAC7.taxon	discussion	Remarks. Propodus of gnathopod 1 on juveniles can be not inverted as in adults. Some species on the entire telson group can have a slightly cleft telson in juvenile stages.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C078072D033FD9C97E1FA02.taxon	materials_examined	Material examined. REVIZEE program, R / V Thalassa col., stn. D­ 0504, 19 º 42.734 S; 038 º 36.472 W, 910 m, 06 / 29 / 1999; 1 female with oostegites, 32 mm, MNRJ 13702. Stn. E­ 0551, 21 º 0 7.780 S; 039 º 49.106 to 21 º 0 4.783 S; 039 º 48.698 W, 1642 m, 07 / 06 / 2000, 1 female with oostegites, 24 mm, 1 juvenile, 6 mm, both attached to Bathypterois phenax Parr, MNRJ 15146. Type locality. Southwest Indian Ocean, off Madagascar, 21 º 30 ' S – 43 º W.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C078072D033FD9C97E1FA02.taxon	diagnosis	Diagnosis. Eyes absent. Maxilliped palp with 4 articles and longer than outer plate. Gnathopod 1 propodus subquadrate. Coxa 2 with anterior margin acute. Pereopod 3 basis 2 X length of carpus. Telson entire.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C078072D033FD9C97E1FA02.taxon	description	Description. Female, 24 mm and juvenile, 6 mm (Figs 1, 2 A). Rostrum a little shorter than article 1 of antenna 1 peduncle. Eyes absent. Antenna 1, article 1 of peduncle longer than articles 2 – 3 together; callynophore present. Antenna 2, article 4 of peduncle slightly longer than article 5. Mandibles with distal incisors; palp 3 ­ articulate and with marginal setae. Maxilla 1, outer plate with 8 distal setae. Maxilla 2, inner and outer plate subequal in length. Maxilliped, outer plate longer than inner plate; palp with 4 articles and longer than outer plate. Gnathopod 1 (Fig. 2 B), strongly subchelate; coxa reduced and partially covered by coxa 2; propodus inverted on adult stage, robust, subquadrate and with anterior lobe; palm with medial groove, stout setae in its extension and 3 pairs of longer setae distally. Gnathopod 2 (Fig. 2 C), coxa with anterior margin acute; basis about 2 X length of ischium; carpus longer than 2 X the length of propodus; dactylus reduced. Coxa 3 longer than broad. Coxa 4 posteriorly excavated. Pereopods 3 (Fig. 2 D) and 4, basis 2 X length of carpus; carpus subequal to propodus and longer than merus. Pereopods 5 – 7, coxa broader than long; basis longer than broad, with posterior lobe; merus subequal in length to carpus and propodus; dactylus as long as half the length of propodus. Uropods 1 and 2, peduncle subequal in length to outer ramus; inner ramus slightly longer than outer ramus. Uropod 3, peduncle slightly smaller than half of outer ramus; inner and outer rami subequal in length; outer ramus 2 ­ articulate, with basal article 5 X length of distal article. Telson entire, distally rounded (Fig. 2 E).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C078072D033FD9C97E1FA02.taxon	distribution	Distribution. Southwest Indian Ocean, off Madagascar. Southwest Atlantic Ocean, off Brazilian coast (19 º to 21 º S).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C078072D033FD9C97E1FA02.taxon	discussion	Remarks. Trischizostoma denticulatum is similar to Trischizostoma raschi Boeck 1861 and Trischizostoma crosnieri Lowry & Stoddart 1993 by the subtriangular shape of coxa 2 and the length of pereopod 3. The distinctives between them are the absence of eyes in T. denticulatum and the shape of propodus of gnathopod 1, which is subquadrate in T. denticulatum and triangular in T. raschi and T. crosnieri. Some characters may change according with the development of the individual. The propodus of gnathopod 1 is quadrate and without any lobe in juveniles and subquadrate and with anterior lobe in adults; the length of gnathopod 2 propodus is relatively longer in juveniles; and the telson is slightly cleft in juveniles and entire in adults. Distinctions between the individuals of this study and the description of Ledoyer (1978) were observed. The anterior margin of coxa 2 seems to be more rounded in the Ledoyers material. Another difference is the relative length of the propodus of gnathopod 2 compared to carpus. Ledoyer (1978) described the carpus about 3 X longer than propodus, and the Brazilian specimens have the carpus about 2.2 X longer than propodus.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C018071D033FA5C903BFE42.taxon	materials_examined	Material examined. REVIZEE Program, R / V Thalassa col., stn. E­ 0509, 15 º 47.725 ' S, 038 º 21.973 ' W to 15 º 46.378 ' S, 038 º 24.839 ' W, 2076 m. 12 / 06 / 2000; 1 female, 47 mm, ovigerous, MNRJ 15141. Stn. E­ 0528, 19 º 45.258 ' S, 039 º 03.003 ' W to 19 º 47.581 ' S, 038 º 59.827 ' W, 1237 m, 29 / 06 / 2000, 1 female with oostegites, 25 mm, MNRJ 15142. Stn. E­ 0 535, 19 º 58.936 ' S, 039 º 38.657 ' W to 19 º 56.087 ' S, 039 º 35.408 ' W, 1002 m, 01 / 07 / 2000, 1 female with oostegites, 39 mm, MNRJ 15143. Type locality. Northeast Atlantic, between Dakar and Cabo Verde Islands. Diagnosis. Eyes present. Maxilliped palp with 4 articles and longer than outer plate. Gnathopod 1 propodus oval and anteriorly excavate. Gnathopod 2, coxa with anterior margin rounded; ischium subequal to carpus in length. Pereopod 3 basis 2 X length of propodus. Telson entire, distally truncate.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C018071D033FA5C903BFE42.taxon	description	Description. Female, 39 mm (Fig. 3 A). Rostrum reaching middle of first article of antenna 1 peduncle. Eyes well developed. Antenna 1, first article of peduncle longer than articles 2 – 3 and shorter than callynophore. Antenna 2, peduncle article 4 subequal in length and broader than article 5. Mandibles with small distal incisor; palp 3 ­ articulate and bearing marginal setae. Maxilla 1, inner plate 1 / 3 length of outer plate, with 8 distal setae, palp reduced and attached on median part of outer plate. Maxilla 2, inner and outer plates subequal in length; outer plate with 4 lateral setae. Maxilliped, inner plate shorter than outer plate; palp with 4 articles and longer than outer plate. Gnathopod 1 (Fig. 3 B), strongly subchelate; coxa reduced and partially covered by coxa 2; propodus inverted, oval, anteriorly excavated; palm with stout setae in all its extension and 3 pairs of longer setae distally. Gnathopod 2 (Fig. 3 C), coxa with anterior margin rounded; ischium shorter than basis and subequal to carpus; propodus less than half­length of carpus; dactylus reduced. Pereopod 3 (Fig. 3 D), coxa longer than broad; basis 2 X length of propodus; carpus slightly longer than propodus; dactylus less than halflength of propodus; carpus, propodus and dactylus covered with minute and stout setae on posterior margin. Pereopod 4, coxa posteriorly excavated; basis longer than carpus and merus together; propodus as long as carpus; dactylus less than half­length of propodus. Coxae 5 – 7 broader than long. Basis of pereopods 5 – 7 longer than broad and with posterior lobe. Pereopods 5 and 7, carpus as long as merus, and longer than propodus. Pereopod 6, carpus as long as propodus and slightly shorter than merus. Uropods 1 and 2, peduncle subequal to outer ramus; inner ramus slightly longer than outer ramus. Uropod 3, peduncle less than half of outer ramus; inner and outer rami subequal in length; outer ramus 2 ­ articulate, with a basal article 5 X length of distal article. Telson entire, truncate (Fig. 3 E).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C018071D033FA5C903BFE42.taxon	distribution	Distribution. North Atlantic and Southwest Atlantic, off Brazilian coast (15 º to 19 º S).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C018071D033FA5C903BFE42.taxon	discussion	Remarks. Trischizostoma longirostrum is part of the group of species with maxilliped palp longer than outer plate, anterior margin of coxa 2 rounded, and telson entire, which includes: T. richeri Lowry & Stoddart 1994, T. nicaeense Costa 1853, T. macrochela Vinogradov 1990, and T. circulare. Among these species, T. longirostrum is very close to T. richeri in the oval shape of propodus of gnathopod 1. The distinctions between them are on carpus of gnathopod 2, which is subequal to ischium in T. longirostrum and longer than ischium in T. richeri; basis of pereopod 3, which is twice the length of propodus in T. longirostrum and 3 X the length of propodus in T. richeri; the anterior margin of propodus of gnathopod 1, which is excavated in T. longirostrum; and the telson shape, which is distally truncate in T. longirostrum and distally acute in T. richeri. Chevreux (1927) used the length of rostrum as a diagnostic character. However, this character is variable in different stages of the individual within this genus. Examining juvenile specimens of T. raschi and T. denticulatum showed that the rostrum is relatively longer when compared with adults forms. A curiosity observed was the absence of eyes in the largest individual (47 mm) found within our samples. Smaller specimens (25 mm and 39 mm) had weak eyes. Modification on the ending of the specific name is proposed. The name Trischizostoma (from the Greek stoma, mouth) has a neuter gender that needs to be followed by the correct adjective declination um (Brown, 1956).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C02807FD033FD9C9244FC4A.taxon	description	Trischizostoma raschi — Diviacco & Ruffo, 1989: 559, fig. 383.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C02807FD033FD9C9244FC4A.taxon	materials_examined	Material examined. REVIZEE Program, R / V Thalassa col., stn. E­ 0507, 15 º 08.595 ' S, 038 º 40.638 ' W to 15 º 07.158 ' S, 038 º 40.542 ' W, 1026 m, 1 ovigerous female, 39 mm, MNRJ 15139. Stn. E­ 0535, 19 º 59.936 ' S, 039 º 38.657 ' W to 19 º 56.087 ' S, 039 º 35.408 W, 1002 m, 1 ovigerous female, 29 mm, MNRJ 19251. Stn. E­ 0523, 19 º 42.569 ' S, 038 º 32.030 ' W to 19 º 42.685 ' S, 038 º 36.961 ' W, 922 m, 1 ovigerous female, 27 mm, MNRJ 15145. Type locality. North Atlantic, off Norway coast.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C02807FD033FD9C9244FC4A.taxon	diagnosis	Diagnosis. Eyes well developed. Maxilliped palp with 4 articles and longer than outer plate. Gnathopod 1 propodus of triangular. Coxa 2 with anterior margin acute. Coxa 4 posteriorly excavated, with postero­ventral lobe. Telson emarginate.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C02807FD033FD9C9244FC4A.taxon	description	Description. Female, 29 mm (Fig. 4 A). Rostrum reaching halfway of first article of antenna 1 peduncle. Eyes well developed. Antenna 1, article 1 of peduncle more than twice length of articles 2 – 3 together; flagellum with 9 articles; callynophore present. Antenna 2, article 5 slightly longer than article 4. Mandibles with distal incisors; palp 3 ­ articulate with marginal setae. Maxilla 1, inner plate 1 / 3 of outer plate length; outer plate with 8 distal setae and palp attached medially. Maxilla 2, inner plate slightly shorter than outer plate; outer plate with 3 lateral setae. Maxilliped, inner plate shorter than outer plate; palp with 4 articles and longer than outer plate. Gnathopod 1 strongly subchelate (Fig. 4 B); coxa reduced and partially covered by coxa 2; propodus inverted, robust, triangular; palm slightly convex with stout setae along all its extension and 3 pairs of longer setae distally. Gnathopod 2 (Fig. 4 C), coxa subtriangular, with acute anterior margin; basis 2 X length of ischium, which is longer than carpus; dactylus reduced. Pereopod 3 (Fig. 4 D), coxa longer than broad; basis longer than merus; carpus as long as propodus; propodus and dactylus with minute setae on posterior margin. Pereopod 4, coxa posteriorly excavated, with postero­ventral lobe; basis as long as merus; carpus and propodus subequal in length. Pereopods 5 – 7, coxae broader than long; basis with posterior lobe; carpus and merus subequal in length; dactylus half length of propodus. Uropods 1 and 2, peduncle subequal to outer ramus; inner ramus slightly longer than outer ramus. Uropod 3, peduncle slightly shorter than half of outer ramus; inner and outer rami subequal in length; outer ramus 2 ­ articulate, with basal article 5 X length of distal article. Telson entire, emarginate (Fig. 4 E).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C02807FD033FD9C9244FC4A.taxon	distribution	Distribution. North Atlantic, Mediterranean Sea and Southwest Atlantic, off Brazilian coast (15 º to 19 º S).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C02807FD033FD9C9244FC4A.taxon	discussion	Remarks. Trischizostoma raschi is similar to T. denticulatum, T. circulare, T. longirostrum, T. richeri, T. nicaeense and T. crosnieri in having the maxilliped palp longer than the outer plate and the telson entire. It differs from T. nicaeense (see Sexton, 1908), T. circulare, T. longirostrum and T. richeri in the shape of the anterior margin of coxa 2, which is acute in T. raschi and rounded in other species. It also differs from T. denticulatum in the triangular propodus of gnathopod 1, which is subquadrate in the latter. Seemingly, T. raschi is very close to T. crosnieri in the acute anterior margin of coxa 2 and the triangular propodus of gnathopod 1. Lowry & Stoddart (1993) indicated that the number of stout setae on the palm of the gnathopod 1, the posterior lobe of the basis of pereopod 6 and shape of the telson as diagnostic characters between these species. However, the conspicuous distinction is in the telson, which is entire in T. raschi and cleft in T. crosnieri. Some characters may change according to the development of the individual. Juveniles of T. raschi, removed from a mature female, have the telson cleft, a relative longer propodus of gnathopod 1 and the palm without setae when compared with the adult forms (Fig. 4 F). Detailed examination in some juveniles (30 specimens) suggests that the setae on the palm of gnathopod 1 appeared at the same time and not by addition in each distinct molt.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0C807DD033FB949754FC1A.taxon	materials_examined	Material examined. REVIZEE Program, N. O. Thalassa col., stn. E­ 0510, 15 º 48.503 ' S, 038 º 36.265 ' W to 15 º 47.383 ' S, 038 º 36.154 ' W, 599 m, 12 / 06 / 2000; 1 female with oostegites, 61 mm, MNRJ 15138. Type locality. Southwest Pacific Ocean, Loyalty Islands Basin, 21 º 12.05 ' S, 166 º 59.85 ' E, 2190 to 2205 m.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0C807DD033FB949754FC1A.taxon	diagnosis	Diagnosis. Eyes well developed. Maxilliped palp longer than outer plate. Gnathopod 1 propodus oval; palm with 19 short robust setae and 3 pairs of long robust setae distally. Coxa 2 with anterior margin rounded. Gnathopod 2 carpus longer than ischium. Pereopod 3 basis 3 X of propodus length. Telson entire, subacute.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0C807DD033FB949754FC1A.taxon	description	Description. Female, 61 mm (Fig. 5 A). Rostrum reaching end of article 1 of peduncle of antenna 1. Eyes well developed. Antenna 1, article 1 of peduncle slightly longer than articles 2 – 3; callynophore present. Antenna 2, article 4 of peduncle slightly shorter than article 5. Mandibles with distal incisors; palp 3 ­ articulate with lateral setae. Maxilla 1, inner plate 1 / 3 length of outer plate; outer plate with 8 distal setae. Maxilla 2, inner and outer plates subequal in length; outer plate with 5 lateral setae. Maxilliped, inner plate shorter than outer plate; palp with 4 articles and longer than outer plate.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0C807DD033FB949754FC1A.taxon	description	Uropods 1 and 2, peduncle subequal to outer ramus; inner ramus slightly longer than outer ramus. Uropod 3, peduncle slightly shorter than half of outer ramus; inner and outer rami subequal in length; outer ramus 2 ­ articulate, with basal article 5 X length of distal article. Telson entire, subacute (Fig. 4 E).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0C807DD033FB949754FC1A.taxon	distribution	Distribution. Southwest Pacific Ocean, Loyalty Islands Basin; Southwest Atlantic Ocean, off Brazilian coast (15 º S).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0C807DD033FB949754FC1A.taxon	discussion	Remarks. Trischizostoma richeri was recently described and compared with other species of the genus (Lowry & Stoddart, 1994). The Brazilian sample agrees with the type material in the diagnostic characters such as carpus of gnathopod 2 longer than ischium, basis of pereopod 3 3 X the propodus length and telson entire, subacute.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0E807BD033FC449613FD52.taxon	materials_examined	Material examined. REVIZEE Program, N. O. Thalassa col., stn. E­ 0540, 21 º 12.293 ' S, 040 º 00.884 ' W to 21 º 09.576 ' S, 040 º 00.461 ' W, 1364 m, 04 / 07 / 2000; 1 female with oostegites, 34 mm, MNRJ 15144.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0E807BD033FC449613FD52.taxon	etymology	Etymology. The name of this species is dedicated in honor to Dr. Paulo Costa, head of the Brazilian Fisheries REVIZEE program — Central Campaign, who always encourages the research on the material obtained in this scientific program.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0E807BD033FC449613FD52.taxon	diagnosis	Diagnosis. Maxilliped palp longer than outer plate. Propodus of gnathopod 1 oval and with 11 short and long stout setae on its extension and 3 pairs of long stout setae distally. Coxa 2 with anterior margin rounded. Carpus of gnathopod 2 longer than ischium. Basis of pereopod 3 3 X propodus length. Telson entire, triangular.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0E807BD033FC449613FD52.taxon	description	Description. Female, 34 mm (Fig. 6 A). Rostrum reaching the end of article 1 of peduncle of antenna 1. Eyes well developed. Antenna 1, article 1 of peduncle longer than articles 2 – 3; callynophore present. Antenna 2, article 5 of peduncle as long as article 4. Mandibles with distal incisors; palp 3 ­ articulate with lateral setae. Maxilla 1, outer plate with 8 distal setae. Maxilla 2, inner and outer plates subequal in length; outer plate with 3 lateral setae. Maxilliped, outer plate longer than inner plate; palp with 4 articles, longer than outer plate. Gnathopod 1 (Fig. 6 B) strongly subchelate; coxa reduced and partially covered by coxa 2; propodus inverted, robust, oval; palm with 11 short and long stout setae in its extension and 3 pairs of long stout setae distally. Gnathopod 2 (Fig. 6 C), coxa with anterior margin rounded; carpus slightly longer than ischium; merus shorter than ischium; propodus shorter than half of carpus; dactylus reduced. Pereopod 3 (Fig. 6 D), coxa longer than broad; basis 3 X length of propodus; carpus as long as merus, with stout setae on anterior and posterior margins; propodus more than twice length of dactylus, with stout setae on posterior margin; propodus and carpus covered with minute setae on posterior margin. Pereopod 4, coxa posteriorly excavated; basis more than 2 X length of merus; carpus as long as merus and longer than propodus; dactylus with half length of propodus. Pereopod 5, coxa broader than long; basis with posterior lobe; merus as long as carpus and shorter than propodus; dactylus 1 / 3 of propodus. Pereopods 6 and 7, coxa broader than long; basis with posterior lobe; merus as long as carpus and longer than propodus; dactylus 3 X shorter than propodus. Uropods 1 and 2, peduncle subequal to outer ramus; inner ramus slightly longer than outer ramus. Uropod 3, peduncle slightly less than half of outer ramus; inner and outer rami subequal in length; outer ramus 2 ­ articulate, with basal article 5 X length of distal article. Telson entire, triangular (Fig. 6 E).	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
03A012206C0E807BD033FC449613FD52.taxon	discussion	Remarks. Trischizostoma costai sp. nov. is similar to T. richeri in the shape of the propodus of gnathopod 1, and shape of coxa 2. However, there is a conspicuous distinction in the size of the eyes, much larger in T. richeri, and in the number of stout setae on the palm of gnathopod 1, with 11 setae on T. costai sp. nov., and 19 setae on T. richeri. According to observations on juveniles of T. raschi, it seems that all the setae on the palm appears at the same time and not gradually by each molt. Also, T. costai sp. nov. presents oostegites, indicating that this specimen is a mature female and not a possible juvenile of T. richeri.	en	Freire, Pablo R., Serejo, Cristiana S. (2004): The genus Trischizostoma (Crustacea: Amphipoda: Trischizostomidae) from the Southwest Atlantic, collected by the REVIZEE Program. Zootaxa 645: 1-15, DOI: 10.5281/zenodo.158742
