Final-stage phyllosoma of Palinustus A. Milne-Edwards, 1880 (Crustacea: Decapoda: Achelata: Palinuridae) — The first complete description Author Palero, Ferran Author Guerao, Guillermo Author Clark, Paul F. Author Abelló, Pere text Zootaxa 2010 2403 42 58 journal article 10.5281/zenodo.194110 b3e3ec7e-f965-450a-8797-09537ea56826 1175-5326 194110 Palinustus A. Milne-Edwards, 1880 Figs 2–13 Phyllosoma a Cephalic shield ( Fig. 2 A). CW/CL = 0.84, maximum width located close to mid length; eye longer than antennule. Antennule ( Fig. 2 A, B). Peduncle 3-segmented, segments 1–3 without setae, with proportional lengths of 3.3: 1: 2.1; inner flagellum slightly longer than outer with sparsely setae; outer flagellum with 14 rows of sensory setae. Antenna ( Fig. 2 A). About 2.5 × as long as antennule and about 1.8 as long as eyes; peduncle 3-segmented, distal segment with 4 terminal spines; flagellum unsegmented with 3–4 spines on proximal half. Maxillule ( Fig. 3 A). Coxal endite with 13 setae (4 long plumose); basial endite with 2 strong cuspidate setae and 7 subterminal setae; endopod vestigial with one seta present. Maxilla ( Fig. 3 B). Coxal and basial endites and endopod not differentiated, with 4 setae; scaphognathite margin with 42 plumose setae. FIGURE 2. Palinustus sp. Phyllosoma a. A, ventral view, B, detail of antennule. Scale bars: A = 2 mm; B = 1 mm. First maxilliped ( Fig. 3 B). Elongated bud, without setae. Second maxilliped ( Fig. 3 C, D). Biramous, protopod 2-segmented with one minute seta on distal segment (basis); endopod 4-segmented with 0, 1, 11, 6 setae, ischio-merus fused to basis; exopod flagellated (with 6–7 annulations), each annulation bears a pair of setae. Third maxilliped ( Fig. 2 A). Biramous, with ventral coxal spine and without subexopodal spine on basis; endopod 4-segmented, with one distal spine on ischio-merus, distal part of propodus and dactylus densely setose; exopod with 25 annulations, each annulation with a pair of plumose setae. Pereiopods ( Figs. 2 A, 3E). Pereiopods 1–4 biramous, with coxal spine, basis with sparse spines on its surface and subexopodal spine; exopods with 25, 30, 31, 27 annulations, respectively, and each annulation bearing a pair of setae; pereiopod 5 uniramous, 3-segmented with 1, 1, 0 spines, reaching distal margin of telson. Pleon ( Figs. 2 A, 3F). Somites 2–6 differentiated and segmented; pleopods 2–5 biramous, protopod and appendix interna not differentiated, without spines or setae; uropods biramous with protopod well differentiated, without spines or setae. FIGURE 3. Palinustus sp. Phyllosoma a. A, maxillule; B, maxilla (mx2) and first maxilliped (mxpd 1); C, second maxilliped; D, detail of second maxilliped; E, pereiopod 5; F, pleon, ventral view. Scale bars: A and D = 0.1 mm; B and C = 0.2 mm, E = 0.6 mm; F = 1 mm. Phyllosoma b Final stage Cephalic shield ( Figs. 4 A, 5A). Subrectangular, slightly long than wider (CW/CL = 0.95), and 1.7 × wider than thorax; 2 processes on anterodorsal surface, near base of antenna (see Fig. 5 A); eye similar in length to antennule. Antennule ( Fig. 4 A, B). Biramous, extending slightly beyond end of peduncle of antenna; segments of peduncle 1 to 3 with proportional lengths of 3.2: 1: 2.1; inner ramus unsegmented and setose, slightly longer than outer; outer ramus unsegmented with 22 rows of sensory setae. FIGURE 4. Palinustus sp. Phyllosoma b. A, ventral view; B, detail of antennule; C, detail of antennal peduncle. Scale bars: A = 10 mm; B = 2 mm; C = 0.5 mm. Antenna ( Fig. 4 A, C). About 4.6 × longer than antennule, similar in length to TL; segments 1–3 of peduncle with 0, 1, 5 (one medial and 4 distal) spines respectively; flagellum spinose. Mandible ( Fig. 5 B). Flattened, with asymmetrical dentition; incisor process and medial gnathal edge with a series of teeth; molar process crowned by many denticules and papillae. Maxillule ( Fig. 5 C). Coxal endite with 15 setae (6 long plumose); basial endite with 2 strong terminal cuspidate setae and 7 setae (one terminal and 6 subterminal); endopod vestigial with two setae present. Maxilla ( Fig. 5 D). Coxal and basial endites and endopod poorly differentiated, with 6–7 minute simple setae; scaphognathite flattened and considerably expanded to anterior and posterior, with 80 marginal plumose setae (4 or 5 posterior setae longest). First maxilliped ( Fig. 5 E). Epipod differentiated; exopod developed and incipiently 2-segmented; endopod absent. Second maxilliped ( Figs. 4 A, 5F). Biramous, endopod 4-segmented, with 2, 2, 17, 11 setae; exopod flagellated with 22 annulations, each bearing a pair of setae; epipodite present. Third maxilliped ( Fig. 4 A). Biramous, with ventral coxal spine, but subexopodal spine absent; endopod 4- segmented, with one distal spine on ischio-merus; distal part of propodus and dactylus densely setose; exopod flagellated with 26 annulations. Pereiopods ( Figs. 4 A, 6A-D, 7A, B). Pereiopods 1–4 biramous, with coxal spine, basis spinose and subexopodal spine present; endopod four-segmented, endopods of pereiopods 1, 3 and 4 chelated and pereiopod 2 subchelated; exopods flagellated distally with 36, 34, 32, 31 annulations, respectively, each bearing a pair of setae; pereiopod 5 uniramous, 5-segmented, reaching posterior margin of telson, with 1, 4, 3, 4, 0 spines ( Fig. 7 B). FIGURE 5. Palinustus sp. Phyllosoma b. A, frontal area, dorsal view; B, Mandible; C, maxillule; D, maxilla; E, first maxilliped; F, detail of second maxilliped. Scale bars: A = 2 mm; B = 0.5 mm; C, E and F = 0.35 mm; D = 0.7 mm. Gills ( Figs. 6 E, F). Third maxilliped and pereiopod 1 with one pleurobranch, one arthrobranch and epipod with podobranch; pereiopods 2–4 with two pleurobranches, one arthrobranch and epipod with podobranch; pereiopod 5 with one pleurobranch. Pleon ( Figs. 4 A, 7A). Segmented, with 6 somites, somite 1 incompletely separated from thorax dorsally; posterior margin of somite 6 with 4 spines: 2 median and 1 on each posterolateral angle; somites 2–5 with paired pleopods; pleopods biramous ( Fig. 7 C, D), with one spinose seta plus 0–2 minute, subdistal setae at tip of endopod and exopod, endopod with appendix interna; biramous uropods reaching posterior margin of telson, exopod with a medial lateral spine; telson longer than broad, subrectangular. FIGURE 6. Palinustus sp. Phyllosoma b. A-D, pereiopods, distal part of endopods; E, left side of thorax, dorsal view; F, detail of epipod and podobranch of pereiopod 3. Abbreviations: art, arthrobranch; epi, epipod; ple, pleurobranch; pod, podobranch. Scale bars: A-D = 0.4 mm; E = 5 mm; F = 0.6 mm. Phyllosoma c Final stage Cephalic shield ( Fig. 8 A). Subrectangular, slightly longer than wide (CW/CL = 0.92), and 1.7 × wider than thorax; two processes on anterodorsal surface, near base of antenna; eye similar in length to antennule. Antennule ( Fig. 8 A, B). Biramous, extending slightly beyond end of peduncle of antenna; segments of peduncle 1–3 with proportional lengths of 3.7: 1: 2.2; inner ramus unsegmented and setose, slightly longer than outer; outer ramus unsegmented with 23 rows of sensory setae. Antenna ( Fig. 8 A, C). About 5 × longer than antennule, similar in length to the TL; segments 1–3 of penducle with 0, 1, 5 (one medial and 4 distal) spines respectively; flagellum spinose in its proximal area. Maxillule ( Fig. 9 A). Coxal endite with 16 setae (5 long plumose); basial endite with 2 strong terminal cuspidate setae and 11 setae (one terminal and 10 subterminal); without endopodal setae. Maxilla ( Fig. 9 B). Coxal and basial endites and endopod not differentiated, with 6 minute setae; scaphognathite flattened and considerably expanded to anterior and posterior, with 78 marginal plumose setae (4 or 5 posterior setae longest). FIGURE 7. Palinustus sp. Phyllosoma b. A, pleon; B, pereiopod 5; C, pleopod; D, detail of pleopod tip. Scale bars: A = 5 mm; B = 2 mm; C= 0.5 mm; D = 0.2 mm. First maxilliped ( Fig. 9 C). Epipod differentiated; exopod developed and incipiently 2-segmented. Second maxilliped ( Figs. 8 A, 9D, E). Biramous, endopod 4-segmented, with 1, 1, 15, 9 setae; exopod flagellated with 22 annulations, each bearing a pair of setae; epipodite present. Third maxilliped ( Fig. 8 A). Biramous, with ventral coxal spine and without subexopodal spine; endopod 4-segmented, with one distal spine on ischio-merus; distal part of propodus and dactylus densely setose; exopod flagellated with 36 annulations, each annulation bears a pair of setae. Pereiopods ( Figs. 8 A, 10A, B). Pereiopods 1–4 biramous, with coxal and subexopodal spine; exopods flagellated distally with 36, 36, 34, 31 annulations, each bearing a pair of setae; pereiopod 5 uniramous, 5- segmented, not reaching posterior margin of telson, with 1, 4, 3, 6, 0 spines as figured in Fig. 10 B. Gills (not figured). Third maxilliped and pereiopod 1 with one pleurobranch, one arthrobranch and epipod with podobranch; pereiopods 2–4 with two pleurobranches, one arthrobranch and epipod with podobranch; pereiopod 5 with one pleurobranch. Pleon ( Figs. 8 A, 10A). Segmented, with 6 somites, somite 1 incompletely separated from thorax dorsally; posterior margin of somite 6 with 4 spines: 2 median and 1 on each posterolateral angle; somites 2–5 with paired pleopods; pleopods biramous, with one spinose seta plus 0–2 minute setae at tip of endopod and exopod; endopod with appendix interna; biramous uropods reaching posterior margin of telson, exopod with a medial lateral spine; telson longer than broad, subrectangulate. FIGURE 8. Palinustus sp. Phyllosoma c. A, ventral view; B, detail of antennule; C, detail of antennal peduncle. Scale bars: A = 10 mm; B = 1 mm; C = 0.5 mm. Phyllosoma d Final stage Cephalic shield ( Fig. 11 A). Subrectangular, slightly longer than wide (CW/CL = 0.99), and 1.7 × wider than thorax; two processes on anterodorsal surface, near base of antenna; eye similar in length to antennule. Antennule ( Fig. 11 A, B). Biramous, extending beyond end of peduncle of antenna; segments 1 to 3 of peduncle with proportional lengths of 4: 1: 2.4; inner ramus unsegmented and setose, slightly longer than outer; outer ramus unsegmented with 24 rows of sensory setae. Antenna ( Fig. 11 A, C). Segments 1–3 of peduncle with 0, 2, 5 (one medial and 4 distal) spines respectively; flagellum spinose in its proximal half. Maxillule ( Fig. 12 A). Coxal endite with 16 setae (6 long plumose); basial endite with 2 strong terminal cuspidate setae and 8 setae (one terminal and 7 subterminal); endopod vestigial with two setae present. Maxilla ( Fig. 12 B). Coxal and basial endites and endopod not differentiated, with 9 minute setae; scaphognathite flattened and considerably expanded to anterior and posterior, with>70 marginal plumose setae (5 posterior setae longest). First maxilliped ( Fig. 12 C). Epipod differentiated; exopod developed and incipiently 2-segmented; endopod absent. FIGURE 9. Palinustus sp. Phyllosoma c. A, maxillule; B, maxilla; C, first maxilliped; D, second maxilliped; E, detail of second maxilliped. Scale bars: A, C and E = 0.4 mm; B = 0.5 mm; D = 1 mm. Second maxilliped ( Figs. 11 A, 12D). Biramous, endopod 4-segmented, with 1, 1, 24, 11 setae; exopod flagellated with 22 annulations, each bearing a pair of setae; epipodite present. Third maxilliped ( Fig. 11 A). Biramous, with ventral coxal spine and without subexopodal spine; exopod flagellated with 32 annulations. Pereiopods ( Figs. 11 A, 13A). Pereiopods 1–4 biramous, with coxal and subexopodal spine; exopods flagellated distally with 37, 36, 33, 30 annulations, each bearing a pair of setae; pereiopod 5 uniramous, 5- segmented, reaching posterior margin of telson, with 1, 3, 3, 6, 0 spines ( Fig. 13 A). Gills. Third maxilliped and pereiopod 1 with one pleurobranch, one arthrobranch and epipod with podobranch; pereiopods 2–4 with two pleurobranches, one arthrobranch and epipod with podobranch; pereiopod 5 with one pleurobranch. Pleon ( Figs. 11 A, 13A, B). Segmented, with 6 somites, somite 1 incompletely separated from thorax dorsally (see Fig. 13 A); posterior margin of somite 6 with 4 spines: 2 median and 1 on each posterolateral angle; somites 2–5 with paired pleopods; pleopods biramous ( Fig. 13 C, D), with one spinose seta plus 1–2 minute setae at tip of endopod and exopod; endopod with appendix interna; biramous uropods reaching posterior margin of telson, exopod with medial lateral spine; telson longer than broad, subrectangulate.