Bioacoustics of Armadillo mayeti

Redescription (based on specimens from Soukra, Sfax ) Body length male 9.7 mm , female 8 mm . Convex body without elongated antenna and uropods; endoantennal conglobation ( Figure 1 (A)). Colouration uniform, light orange brown ( Figure 1 (A, B)); pereopods and antenna unpigmented ( Figure 1 (B)). Tergal surface covered with fine granulations and short triangular scale-setae better visible under scanning microcope ( Figures 2 (A), 6(C)). Cephalon much wider than long; width:length ratio about 4:1; upper edge straight; devoid of antennal lobes, frontal line well defined, delimiting narrower frontal area; eyes with 10 ommatidia ( Figure 2 (A)). Pereion: pereonites I–VII epimera with noduli laterales inserted near posterior margins; pereonite I grooved on lateral margin on all its length, deeper in its posterior part; schisma deep with rounded lobes, inner lobe surpassing posterior margin of outer lobe. Epimera II welded forward and separated backward with V-shape clearly visible on live specimens, with inner lobe not surpassing posterior margin of epimera ( Figure 2 (B)). Pleon: Male pleonite I with caudal bi-lobed lamellar process on ventral position, triangular with pointed apex and covering the basis of genital papilla ( Figure 2 (C)). Pleonites III–V ( Figure 1 (A)) with rectangular epimera well developed. Five pairs of lungs on exopodites of pleopods not well discernable in preserved specimens. Telson hourglass-shaped, broader than long, ratio about 2:1, basal part three-times longer than distal one, distal margin straight ( Figure 6 (E)). Antennula ( Figure 3 (B)) with second article shorter than proximal and distal one; 9 aesthetacs inserted subapically on distal article. Antennal peduncle with 5 articles, fifth article 1.25 longer than bi-articulated flagellum, distal article of flagellum nearly three-times as long as proximal ( Figure 3 (A)). Mandibles with molar penicil bearing several hairy branches, dense cushion of setae inserted between molar and incisor processes; right mandible bearing 9 + 1 penicils ( Figure 4 (A)), left mandible 4 + 4 penicils ( Figure 4 (B)). Maxillula ( Figure 4 (D)) inner endite bearing 2 long penicils; outer endite composed of 4 + 6 simple teeth. Maxilla ( Figure 4 (E)) apically bilobate bearing thin setae in distal margin; outer lobe slightly more than twice as wide as inner lobe. Maxilliped ( Figure 4 (C)) basis rectangular; endite distal edge bearing 2 short setae; palp with 1 seta in the first article. Pereopods stout, not pigmented. Pereopod 1 ( Figure 5 (A)) carpus with sternal brush of short setae, longitudinal antennal grooming brush; carpus 1 and 7 around 1.5-times longer than merus. Male pereopod 7 ischium without distinct specialisation, basis without distal sternal lobe ( Figure 5 (B)). Stridulation apparatus visible only under scanning electron microscope on propodus of pereopods 4 and 5, forming one row of chain scales ( Figure 6 (A, B)). Regarding its chemical composition, the scale contains numerous elements with a high carbon rate (58.71%) followed by calcium (19.63%), oxygen, aluminium, etc. ( Table 1 ). Male pleopod 1 exopodite short, nearly as long as wide, distal outer margin concave, triangular distal part with broad base and rounded tip ( Figure 5 (C)); endopodite nearly three-times as long as exopodite with distal portion narrowed, slightly bent outwards ( Figure 5 (D)). Pleopod 2 exopodite elongate, concave on outer margin, inner margin straight with elongated and narrowed distal portion; endopodite narrow, as long as exopodite, with tapering distal apical section ( Figure 5 (E)). Uropod covering gap between telson and pleon; protopod flattened with concave medial margin, distal part longer than wide with truncated apex; endopodite inserted ventrally, and covered with setae ( Figure 3 (E)); exopodite tiny, inserted dorsally, near of narrowest part of telson ( Figure 3 (C, D)).