Leucothoe saron, Thomas, James Darwin & Klebba, Kristine N., 2007

Thomas, James Darwin & Klebba, Kristine N., 2007, New species and host associations of commensal leucothoid amphipods from coral reefs in Florida and Belize (Crustacea: Amphipoda), Zootaxa 1494, pp. 1-44 : 20-25

Leucothoe saron n.sp.

Figures 11–13 ; 14c–d

Holotype. Male “A,” 6.72 mm, YPM 38649: JDT Bel 03/02A— 5Dec03; Carrie Bow Caye; N 16º48.136’ x W 88º04.723’; patch reef, rubble bottom, in the sponge Pseudoceratina crassa , 10m; J.D. Thomas and K.N. Klebba, collectors.

Paratypes. Female “B,” 6.85mm, YPM 38650: JDT Bel 03/02A, 5Dec03; Carrie Bow Caye; N 16º48.136’ x W 88º04.723’; patch reef, rubble bottom, in the sponge Pseudoceratina crassa , 10m; J.D. Thomas and K.N. Klebba, collectors.

Diagnosis. Gnathopod 2: distomedial margins of articles 2 and 3 each with long brush of recurved setae. Coxa 3: narrow. Epimera 1–3: ventral margins with four, three and two anteroventral setae.

Description of male holotype “A,” Ratios of antennae 1 and 2, 0.39 and 0.29 X body length; relative lengths of antenna 1 and 2, 1.00:0.76, flagella 11 and 7-segmented, respectively. Anterior margin of head rounded; midventral keel anterior margin sinuous, ventral margin broadly rounded. Coxae 1–4, width ratios 1.00:1.27:0.87:1.30; coxae 5-6 bilobed; coxa 7 reduced, ovate.

Upper lip asymmetrically lobate, anterior margin setose. Mandibles lacking molar; palp 3-articulate, ratio of articles 1–3, 1.00:3.22:3.11; article 2 with five anterior, two posterior, and two apical setae; article 3 with two apical setae; incisors strongly toothed. Left mandible, lacinia mobilis large, toothed; 11 raker spines. Right mandible, lacinia mobilis a small flake; 12 raker spines. Lower lip, inner lobes fused; outer lobes with moderate gape, anterior margins continually setose. Maxilla 1, palp 2-articulate, with five apical setae; outer plate with eight spines and row of subapical setae. Maxilla 2, inner plate with eight stout medial setae and oblique row of thin lateral setae; outer plate with four stout apical setae and row of submarginal lateral setae. Maxilliped, inner and outer plates reduced; inner plate fused, apical lobes each with three serrate setae; outer plate, anterolateral margin with few setae; palp 3-articulate; palp article 1 apical and apicolateral margins with several serrate setae; article 4 anteromedial margin with dense covering of short pubescent setae.

Gnathopod 1, coxa anteroventral margin produced, ventral margin straight, posterior margin slightly produced; basis linear, anterior margin with four short setae, posterior margin bare; carpal lobe, LW 7.33, anterior margin deeply grooved, margins tuberculate, with 13 short setae; propodus, posterior margin finely denticulate with seven submarginal setae interspersed with numerous short setae, lateral margin bare; dactyl long, with linear striations, reaching 0.50 of propodus. Gnathopod 2, coxa subrectangular, LW 1.08, anterior, ventral, and posterior margins slightly rounded; basis linear, anterior margin with 13 short setae, posterior margin lacking setae; distal margin of articles 2 and 3 with a brush of long recurved setae, the latter reaching midway along carpus; carpal lobe expanded distally, apical margin obliquely serrate, reaching 0.68 along propodus; propodus, palm convex with one strong process near insertion of dactyl, remainder of palm evenly rounded with numerous short subapical setae, primary mediofacial setal row reaching 0.66 of propodus, secondary mediofacial row lacking; dactyl strongly recurved with numerous linear striations, reaching 0.68 of propodus.

Pereopod 3, coxa narrow, LW 1.33, anterior margin rounded, ventral margin convex, posterior margin straight. Pereopod 4, coxa anterior margin straight, ventral margin produced, posterior margin slightly excavate. Pereopods 5–7, coxae 5–6 bilobed; coxa 7 small, ventrally convex; pereopods 5–7 bases slightly expanded, LW 1.26:1.15:1.14, posterior margins smooth.

Epimera 1–3, ventral setae 4:3:2, respectively; epimera 3, posteroventral margin rounded. Uropods 1–3, relative lengths 1.00:0.71:0.87; relative lengths of peduncles 1–3, 1.00:0.69:1.00. Uropod 1, peduncle 0.92 X rami length, with one medial and three lateral setae; outer ramus subequal to inner ramus; inner ramus with nine medial and zero lateral setae; outer ramus with seven stout medial and five lateral setae. Uropod 2 shortened, peduncle 0.89 X rami length; outer ramus 0.77 X inner ramus; inner ramus with nine medial and four lateral setae; outer ramus with five medial and three lateral setae. Uropod 3, peduncle 1.28 X rami length; outer ramus 0.93 X inner ramus; inner ramus with one medial and four lateral setae; outer ramus with one medial and four lateral setae. Telson LW 1.68, apical margin tridentate bearing two apical setae.

Description of female paratype “B”. Similar to male except gnathopod 1, basis, anterior margin of basis with five long setae (versus short setae), posterodistal margin with group of six short setae (versus no posterior setae in holotype “A”); gnathopod 2, basis anterior margin with 15 long setae (versus 13 short setae in male); distomedial setal tufts on articles 2 and 3 reduced in length, carpal lobe, apically rounded with three small serrations; propodus, mediofacial setal row with more setae than found in male. Medial surface of propodus with two setae in secondary row, and row of seven submarginal posterior setae on palm.

Etymology. Greek for “broom,” referring to the broom-like row of submarginal setae on the posterior margin of articles 2 and 3 of the second gnathopod.

Relationship. Males of Leucothoe saron are distinguished from all other Western Atlantic species by the broom-like tufts of setae on articles 2 and 3 of the second gnathopod. In other features L. saron resembles many other Western Atlantic species of Leucothoe in the rounded anterior margin of the head, ovate bases of pereopods 5–7, and the general morphology of gnathopod 1. L. saron resembles L. ubouhu in the distal margin of the carpus of gnathopod 2 in males.

Ecology. Known from the sponges Agelas dispar , Pseudoceratina crassa , and Iotrochota birotulata .

Distribution. Western Atlantic, Belize, hard bottom patch reef areas, 1–10 meters.

Figures

FIGURE 11. Leucothoe saron n. sp. male holotype “ A, ” 6.72 mm.

FIGURE 12. Leucothoe saron n. sp. male holotype “ A, ” 6.72 mm; female paratype “ B, ” 6.85 mm.

FIGURE 13. Leucothoe saron n. sp. male holotype “ A, ” 6.72 mm.