Bioacoustics of Ericthonius parabrasiliensis

Description. Based on male holotype , 4.6 mm , AM P70718. Head. E yes large, 2/5 dorsal length of head, situated mainly within lateral lobe of head. Antenna 1 peduncular article 1 distinctly shorter than article 3; flagellum distinctly longer than peduncular article 3, with 13 articles, each with a single aesthetasc. ( Antenna 2 not known in male.) Pereon. Gnathopod 1 distinctly smaller than gnathopod 2; coxa about half length and width of coxa 2, not ventrally setose; basis with midposterior broad expansion; merus with posterodistal forward pointing spine; carpus distinctly longer than propodus; propodus length slightly less than 1.5 x width, posterior margin evenly rounded. Gnathopod 2 carpochelate; coxa 2 separated from coxa 1 and 3 (but not widely), subquadrate, about as broad as deep, much larger than 1 and 3–4, with stridulation ridges along ventral convex margin and cluster of slender setae on anteroventral margin; carpus with distinct free posterodistal expansion with two carpal teeth, posterior margin of carpus with slender setae only; propodus length 2/3 carpus length, rectangular, posterior margin with low rectangular projection in distal third and flat rounded midposterior bump; dactylus approximately 2/3 length of propodus, with apical tuft of setae. Pereopods 3–4 coxae, ventral margin setose; basis anterodistally expanded, flask shaped; merus weakly expanded. Pereopod 5 coxa ventral margin with many long slender and plumose setae, basis posterodistal corner approximately right angled. Pereopod 7 basis length approximately 1.5 width, posterodistal corner rounded right angled. Pleon. Urosomites 1 and 2 with dorsal pair of upright slender setae. Uropod 1 peduncle dorsolateral margin with row of 5 robust setae, outer ramus with 4 lateral and 3 medial robust setae, inner ramus with 4 medial robust setae, apically with 2–3 robust setae. Uropod 2 peduncle dorsolateral margin with 3 robust setae, medial margin with single long robust seta distally, outer ramus lateral margin with 2 robust setae, medial margin without setae; inner ramus lateral margin without setae, medial margin with 3 robust setae, both rami with 2–3 robust setae apically, one of which is twice as long as the others. Uropod 3 peduncle length approximately 2.5 x greatest width, broad proximally, narrowing distally, with 4 dorsolateral slender setae; ramus length approximately 3 x width, distally cusped. Telson midlength 1/3 greatest width, lateral lobes with 2 rows of recurving hooks, distance between lobes equals width of each lobe. Female (sexually dimorphic characters). Based on paratype , 5.2 mm , AM P70675. Gnathopod 1 basis without posterior swelling. Gnathopod 2 coxa rounded, only slightly longer than 1 and 3, with stridulation ridges ventrally; carpus projection with row of 2–4 robust setae on posterior margin and acute apex; propodus posterior margin evenly convex, with group of 3 robust setae level with ventral apex of carpus; dactylus without apical setae. Habitat. On overgrown mooring blocks and lines, 5 to ca. 8 m depth.