Leucothoe oxumae, Alves & Neves & Johnsson, 2020

Alves, Jessika, Neves, Elizabeth & Johnsson, Rodrigo, 2020, Two new Amphilochida (Amphipoda: Amphilochidea) associated with the bioinvasive Tubastraea coccinea fromTodos-os-Santos Bay, Bahia State, Brazil, Zootaxa 4743 (1), pp. 21-34 : 22-27

Leucothoe oxumae sp. nov.

( Figs 1-4 )

urn:lsid:zoobank.org:act:397BC1B2-666D-4E54-9F3F-0712859FDA69

Examined material.

Holotype. Adult male (UFBA 3564), dissected and drawn, 5.5 mm, Cavo Artemidi Shipwreck, TSB, Brazil (13°13’31’’S, 38°31’55’’W), associated with Tubastraea coccinea , 15m depth, 12 th December 2010, N. Menezes coll.

Paratypes. 4 adult males (UFBA 3565), 5.0 mm, Salvador Harbor , TSB, Brazil (12°58’08.0”S 38°30’51.3”W), associated with Tubastraea and Tedania ignis , 10 m depth, 20 th September 2019 .

Etymology. The species name refers to Oxum, deity of fertility and richness for some African religions common in Bahia State. According to these religions, Oxum is represented by two colors: yellow – in reference to richness and prosperity and pink- in reference to beauty. The new species was found associated with Tubastraea spp., known as sun coral because of it external color yellow and orange. The new specimen, even fixed in alcohol, displays little light pink spots.

Diagnosis. Rostrum acute and projected. Lateral cephalic lobes rounded. Antenna 1 about 1/4 of body length, slightly longer than antenna 2. Gnathopod 1 carpochelate, coxa broad, ventrally excavated; propodus with five anterodistal robust setae. Anterior margin of gnathopod 2 basis with several slender setae; distoventral corner of carpus strongly setose; propodus fusiform, slightly serrate on palmar margin. Pereopod 4, coxa 4 posteroventral notch present, posterior margin expanded. Posterodistal corner of epimeral plate 3 produced and rounded.

Description. Rostrum acute and projected, lateral cephalic lobes rounded ( Fig. 2 ). Antenna 1 about 1/4 body length; article 1 0.3 times longer than article 2; article 3 reaching 1/6 of article 1 length, flagellum 12-articulated ( Fig. 2 ). Antenna 2 slightly shorter than antenna 1; flagellum 9-articulated ( Fig. 2 ). Eyes large and subrounded ( Fig. 2 ).

Mouthparts. Epistome triangular ( Fig. 2 ). Upper lip bilobed, with row of apical long setae ( Fig. 2 ). Mandibles with asymmetrical lacinia mobilis; mandible incisor with five teeth; mandibular palp 3-articulated; articles subequal in length (1.0:1.3:1.1); articles 1 and 2 laterally setose and wider than article 3; article 3 with two apical setae ( Fig. 2 ). Maxilliped inner lobe with four apical setae, lateral margin lightly crenulated; palp slender with setose articles ( Fig. 2 ). Maxilla 2 outer lobe apically setose; inner lobe apically and laterally setose ( Fig. 2 ).

Gnathopods. Gnathopod 1 carpochelate, coxa 1 trapezoidal, broad, overlapping head; basis with eight setae, alternating long and short ones along anterior margin; ischium subquadrate; distally expanded; about 1/4 of basis length; merus sickle shaped, slightly shorter than ischium; carpal spur subequal in length to propodus, covered by small setae on posterior edge; propodus 3.4 times longer than wider, palm with five anterodistal robust setae, smooth on proximal region; dactylus reaching less than a half of propodus length ( Fig. 3 ). Gnathopod 2 with coxa 2 broad and subquadrate, overlapping head; basis strong and long, with 10 setae, alternating long and medium ones along posterior margin; ischium anteriorly rounded and expanded, about 1/3 of basis length; posterodistal corner with one seta; merus reduced, posterodistal corner with seta, 0.7 times length of ischium; carpus densely setose, reaching about 1/3 of propodus length; propodus elongate, inflated and fusiform, with five mediofacial long setae; palm oblique with five long facial setae; palmar margin with two spines and one broad process near hinge of dactylus, showing a pronounced and U-shaped excavation near the broad process; palm with row of small and stout setae; dactylus strong, reaching more than ½ of propodus length ( Fig. 3 ).

Pereon. Pereopod 3, coxa 3 broad, lateral margins rounded posteroventral margin with 4 setae; basis about five times longer than large, anterior margin beset with small setae; ischium subquadrate, anterior margin rounded, about 1/4 of merus length, anteroventral corner with seta; merus elongated, about 3 times longer than wide, anterior margin with two setae, anteroventral corner produced with seta, 0.2 times wider than carpus; carpus rectangular, ventral margin irregular, posteroventral corner with two setae; propodus about 0.2 times longer than carpus, posterior margin with four sets of two setae, anteroventral corner with seta; dactylus about 1/3 length of propodus ( Fig. 3 ).

Peropod 4, coxa 4 subrounded, posterodorsal corner with notch; basis about four times longer than large, anterior margin with four setae, anteroventral corner with seta; ischium about 1/5 length of basis, subquadrate, anterior margin rounded; merus elongated, about four times longer than wide, anteroventral corner produced with seta; carpus as wide as merus, about 3 times longer than wide, posteroventral corner acute with seta; propodus longer than carpus (about 0.3 times), anterior margin beset with 5 sets of 2 setae; dactylus reaching 1/4of propodus length ( Fig. 3 ).

Pereopod 5, coxa 5 bilobed, ventral margin beset with several setae; basis expanded, posterior margin subtriangular with medial notch, anterior margin concave, with eight stout setae, anteroventral corner with seta; ischium subrectangular, about 1/5 length of basis, anteroventral and posteroventral corners produced, anteroventral corner with seta; merus elongated, about five times longer than wide, posteroventral margin concave with three setae, posteroventral corner acute, produced, with two setae; carpus about 0.4 times thinner than merus, anterior margin with three small setae, anteroventral corner with seta, posteroventral corner with seta, 0.4 times shorter than propodus; propodus as wide as carpus, about four times longer than merus, anterior margin with five small setae; dactylus with posterior small seta, reaching 1/2 of propodus length ( Fig. 4 ). Pereopod 6, coxa 6 bilobed, ventral margin beset with several setae; basis expanded, lateral margins subtriangular; anterior margin with 6 distal setae, anteroventral corner produced, subquadrate, with seta; ischium about 1/4 of basis length, subquadrate, anteroventral corner acute and produced; merus elongated, about 3.5 times longer than wide, anterior margin straight with stout and small seta, anteroventral corner acute, with seta, posterior margin concave, with seta, posteroventral corner produced and rounded, with two setae; carpus rectangular, about three times longer than wide, anterior margins with three small setae, anteroventral corner with two long setae, posterior margin slightly concave, posteroventral corner with long seta; propodus elongated, about 1.7 times longer than carpus, anterior margin with five small stout setae, anterior ventral corner acute; dactylus reaching 1/3 of propodus length ( Fig. 4 ). Pereopod 7, coxa 7 bilobed, about 0.5 times broader than coxa 6; basis globose, anterior margin concave with 10 small and stout setae, anteroventral corner rounded with thin seta, posterior margin subtriangular, with four anterior setae; ischium subquadrate, about 1/5 of basis length, anteroventral corner acute and produced with long seta; merus elongated, about four times longer than wide, anterior margin straight with medial seta, anteroventral corner produced, acute, with seta, posterior margin concave with two robust setae, posteroventral corner produced, with two stout setae; carpus 0.3 times thinner than merus, about 3.2 times longer than wide, anterior margin with three setae, anteroventral corner with two setae, posteroventral corner with seta; propodus elongated, about two times longer than carpus, anterior margin with eight small and stout setae; dactylus about 0.35 times length of propodus ( Fig. 4 ).

Epimeral plates. Epimeron 1 rounded ( Fig. 4 ). Epimeron 2 with posteroventral corner rounded, not produced ( Fig. 4 ). Epimeron 3 with posteroventral corner produced and rounded ( Fig. 4 ).

Urosome. Uropod 1 longer than uropod 2, peduncle subequal in length to rami; rami subequal in length and beset with small setae ( Fig. 4 ). Uropod 1 0.4 times longer than uropod 2; peduncle about 0.2 times longer than rami, subrectangular, with lateral stout setae; inner and outer ramus leaf shaped and subequal in length. Uropod 2 inner ramus 0.3 times longer than outer one; peduncle subequal in length to outer ramus ( Fig. 4 ). Uropod 3 80% the length of uropod 1, peduncle two times longer than rami, rami subequal in length, beset with small setae. Telson twice longer than wide, entire, narrowing distally, with 2 apical setae ( Fig. 4 ).

Remarks. Leucothoe oxumae sp. nov. is similar to L. spinicarpa by showing: (1) gnathopod 1 dactylus more than 1/3 longer than propodus; (2) lateral cephalic lobes rounded; (3) head rostrum acute and pronounced. Nevertheless, the new species is unique by showing (1) gnathopod 1 propodus with five setae (while L. spinicarpa has10 setae; (2) gnathopod propodus with three acute processes and rounded excavation (while continuously serrated in L. spinicarpa ); (3) pereopods 5-7 coxa with posterior margins subtriangular (in L. spinicarpa the posterior margins are convex) (Cowe 2006). Leucothoe oxumae sp. nov is also similar to de Brazilian species L. occidentalis Reid 1951 by the shape of pereopods 5-7 basis, but the new species is different by having: (1) mandible palp article 3 reaching 50% of article 2 length (while in L. occidentalis , article 3 reaches 1/3 of article 3 length); (2) gnathopod 1 carpus with distal margin serrated and beset with little stout setae (while in L. occidentalis carpus distal margin is smooth and without setae); (3) gnathopod 2 propodus palm with five facial setae and an excavation (while in L. occidentalis the setae and excavation are absent); (4) epimeral plate 3 posteroventral corner strongly produced (while not produced in L. occidentalis ) ( Serejo 1998b).The new species is also different from the Brazilian species L. urospinosa Serejo, 1998b by the: (1) less pronounced process in gnathopod 2 propodus palm (while strongly pronounced in L urospinosa ); (2) mandible palp article 3 subtriangular and long (while conical and short in L. urospinosa ); (3) pereopods 6-7 with basis posterior margins subtriangular (while convex in L. urospinosa ) ( Serejo 1998b). Leucothoe oxumae sp. nov. is also different from other Brazilian species L. leptosa Serejo, 1998 by showing coxae 3-4 smooth in ventral margins; L. laurensi Thomas & Ortiz 1995 by having gnathopod 2 dactylus longer than 1.5 times propodus; L. basilobata Serejo, 1998 by the absence of lobe on the male gnathopod 2 basis.

Leucothoe genus is usually recorded associated with other organisms, as sponges, molluscs, ascidians in tropical waters, being also founded in reef systems ( Thomas & Klebba 2006; Alvarez & Winfield 2009; Ortiz & Winfield 2012). This is the first record of the association between Leucothoe and the bioinvasive Tubastraea coccinea , the exemplars were founded in the same sample of Stenothoe ogumi sp. nov.

Figures

FIGURE 1. Leucothoe oxumae sp. nov. holotype (UFBA 3564) 3.5 mm, Cavo Artemidi Shipwreck, 15 m depth, Todos os Santos Bay, Brazil (13°13’31’’S, 38°31’55’’W). Scale bar: 1.0 mm.

FIGURE 2. Leucothoe oxumae sp. nov. holotype (UFBA 3564) 3.5 mm, Cavo Artemidi Shipwreck, 15 m depth, Todos os Santos Bay, Brazil (13°13’31’’S, 38°31’55’’W). Scale bars: 0.5 mm (H, A1, A2, Gn1, Gn2); 0.1 mm (Mp, l Md, rMd, UL, Mx2); 0.3 mm (palm).

FIGURE 3. Leucothoe oxumae sp. nov. holotype (UFBA 3564) 3.5 mm, Cavo Artemidi Shipwreck,15 m depth, Todos os Santos Bay, Brazil (13°13’31’’S, 38°31’55’’W). Scale bar: 0.5 mm.

FIGURE 4. Leucothoe oxumae sp. nov. holotype (UFBA 3564) 3.5 mm, Cavo Artemidi Shipwreck, 15 m depth, Todos os Santos Bay, Brazil (13°13’31’’S, 38°31’55’’W). Scale bar: 0.5 mm.