Chiromantes ortmanni ( Crosnier, 1965 )

Guerao, Guillermo, Anger, Klaus, Simoni, Riccardo & Cannicci, Stefano, 2012, The early life history of Chiromantes ortmanni (Crosnier, 1965) (Decapoda: Brachyura: Sesarmidae): morphology of larval and juvenile stages, Zootaxa 3347, pp. 36-62 : 39-50

Chiromantes ortmanni ( Crosnier, 1965)

( Figs. 1–13 )

Zoea I. Size. RDL= 0.59 ± 0.02 mm; CL= 0.33 ± 0.03 mm (n= 10).

Carapace ( Fig. 1 A). Globose, smooth, with anterodorsal minute protuberance. Dorsal spine present, well developed and curved posteriorly. Rostral spine present, straight, similar in length to antennal protopod, with sparse minute spines. Lateral spines absent. Pair of simple minute setae on posterodorsal and anterodorsal regions. Posterior and ventral margin without setae. Eyes sessile.

Antennule ( Fig. 1 C). Uniramous. Endopod absent. Exopod unsegmented with 5 terminal aesthetascs and one terminal minute seta.

Antenna ( Fig. 1 D). Similar in size to rostral spine. Protopodal process with two rows of unequal number of spines (15–22) of different sizes. Exopod elongated, with four terminal simple setae (one long, one medium-sized and two very minute). PL/EL = 2.2–2.3.

Mandible. Palp absent; molar and incisor processes well developed.

Maxillule ( Fig. 1 E). Exopod and epipod setae absent. Coxal endite with 6 plumose setae. Basial endite with 5 setae (3 cuspidate and 2 plumodenticulate) and with two teeth. Endopod 2-segmented, with one plumodenticulate seta on the proximal segment and one subterminal and 4 terminal plumodenticulate setae on the distal segment.

Maxilla ( Fig. 1 F). Coxal endite bilobed, with 5 + 3 plumodenticulate setae. Basial endite bilobed with 5+4 plumodenticulate setae. Endopod unsegmented, bilobed, with 2 + 3 long sparsely plumodenticulate setae on inner and outer lobe respectively. Scaphognathite (exopod) with 4 plumose marginal setae and long setose posterior process.

First Maxilliped ( Fig. 1 G). Coxa with one sparsely plumose seta. Basis with 10 medial sparsely plumose setae arranged 2 + 2 + 3 + 3 on inner side, and a mat of long microtrichiae on outer proximal side. Endopod 5-segmented, with 2, 2, 1, 2, 5 (one subterminal + 4 terminal) sparsely plumodenticulate setae, segment 3 with microtrichiae on outer margin. Exopod two-segmented; distal segment with 4 long terminal plumose natatory setae.

Second maxilliped ( Fig. 1 H). Coxa without setae. Basis with 4 medial sparsely plumose setae arranged 1 + 1 + 1 + 1. Endopod 3-segmented, with 0, 1, 6 setae. Exopod two-segmented; distal segment with 4 long terminal plumose natatory setae.

Third maxilliped. Absent.

Pereiopods. Absents.

Pleon ( Fig. 1 A). Five somites plus telson. Pleonites 2 and 3 with a pair of dorsolateral processes. Pleonites 3–5 with posterolateral short pocesses. Pleonites 2–5 with a pair of posterodorsal simple setae.

Pleopods. Absents.

Telson ( Figs. 1 B). Bifurcate, furca large, slightly divergent, with a wide U-shaped median notch and 3 pairs of serrulate setae on posterior margin. Two arrow-shaped and sparsely small spines on furcal arms. FL/BT= 1.4–1.6. Zoea II. Size. RDL= 0.72 ± 0.02 m; CL= 0.40 ± 0.01 m (n= 10).

Carapace ( Fig. 2 A). Two pairs of anterodorsal setae. Each lateroventral margin with one sparsely plumose seta. Eyes stalked.

Maxillule ( Fig. 2 C). Basial endite with 7 setae. Exopod plumose seta present. Maxilla ( Fig. 2 D) Scaphognathite with 8 (3 + 5) plumose marginal setae. First maxilliped. Exopod distal segment with 6 long plumose natatory setae. Second maxilliped. Exopod distal segment with 6 long plumose natatory setae. Pleon ( Fig. 2 B). First somite with one mid-dorsal plumose seta.

Telson ( Figs. 2 A and 2B). Median notch shallower than in the first zoea.

Zoea III. Size. RDL= 0.96 ± 0.02 mm; CL= 0.52 ± 0.02 mm (n= 10).

Carapace ( Fig. 3 A). Three pairs of anterodorsal simple setae. One pair of setae near to the base of the dorsal spine. Each ventral margin with 3 sparsely plumose seta.

Antennule ( Fig. 3 C). Exopod with 4 terminal aesthetascs and one minute terminal seta.

Antenna ( Fig. 3 D). Endopod present as a bud.

Maxilla ( Fig. 3 E). Scaphognathite with 11–12 (7–8 + 4) plumose marginal setae.

First maxilliped ( Fig. 3 F). Endopod segment 3 with one additional seta. Exopod distal segment with 8 long terminal plumose natatory setae.

Second maxilliped. Exopod distal segment with 8 long terminal plumose natatory setae.

Third maxilliped. Present as undifferentiated buds.

Pereiopods. Present as undifferentiated buds.

Pleon ( Fig. 3 B). Pleonite 6 now present, without setae.

Zoea IV. Size. RDL= 1.03 ± 0.07 m; CL= 0.60 ± 0.02 m (n= 10).

Carapace ( Fig. 4 A). One additional pair of setae near to the base of the dorsal spine. Each ventral margin with 6 sparsely plumose setae.

Antennule ( Fig. 4 C). Exopod with one subterminal seta.

Antenna ( Fig. 4 D). Endopod reaching the length of exopod (without setae).

Maxillule ( Fig. 4 E). Basial endite with 11 setae. Epipod seta present.

Maxilla ( Fig. 4 F). Basial endite with 5 + 5 setae. Scaphognathite with 15–16 marginal plumose setae.

First maxilliped ( Fig. 4 G). Fifth segment of endopod with additional subterminal seta. Exopod distal segment with 9 long terminal plumose natatory setae.

Second maxilliped. Exopod distal segment with 10 long terminal plumose natatory setae.

Third maxilliped ( Fig. 4 H). Epipod now present, rudimentary.

Pereiopods ( Fig. 4 H). First pereiopod chelated.

Pleon ( Fig. 4 B). Pleopod buds present.

Telson ( Figs. 4 A and 4B). Without median notch or slightly insinuated.

Zoea V. Size. RDL= 1.26 ± 0.08. 1 mm; CL= 0.73 ± 0.02 mm (n= 7).

Carapace ( Fig. 5 A). Six pairs of anterodorsal setae. Each ventral margin with 8 sparsely plumose setae.

Antennule ( Fig. 5 C). Exopod with one basal seta, and 3 subterminal and 4 terminal aesthetascs.

Antenna ( Fig. 5 D). Endopod 2-segmented, longer reaching 1/2 of the length of spinous process.

Mandible. Mandibular palp bud present.

Maxillule ( Fig. 5 E). Coxal endite with 7 setae. Basial endite with 12 setae.

Maxilla ( Fig. 5 F). Coxal endite with (6–7) + 4 setae. Basial endite with 7 + 6 setae. Scaphognathite with 22–26 marginal plumose setae.

First maxilliped ( Fig. 5 G). Coxa with 2 setae. Exopod distal segment with 11 long plumose natatory setae.

Second maxilliped. Exopod distal segment with 11 long plumose natatory setae.

Third maxilliped ( Fig. 5 H). Slightly segmented, without setae.

Pereiopods ( Fig. 5 H). Chelipeds and pereiopods 2–5 slightly segmented.

Pleon ( Fig. 5 A, B). First somite with three long mid-dorsal setae. Pleopod buds elongated, endopod buds present.

Zoea VI. Size. RDL= 1.39 ± 0.04 mm; CL= 0.80± 0.02 mm (n= 7).

Carapace ( Fig. 6 A). Seven pairs of anterodorsal setae. Each ventral margin with 9 sparsely plumose setae.

Antennule ( Fig. 6 B). Exopod with 2 + 3 subterminal setae.

Antenna ( Fig. 6 C). Endopod with 0–3 long simple terminal setae.

Maxillule ( Fig. 6 E. Coxal endite with 8 setae. Basial endite with 15–16 (14 + 1–2) setae.

Maxilla ( Fig. 6 F).Coxal endite with (7–8) + (4–5) setae. Basial endite with (7–8) + (6–7) setae. Scaphognathite with 26–34 marginal plumose setae and 0–1 lateral seta.

First maxilliped ( Fig. 7 A). Basis with 12 medial sparsely plumose setae arranged 2 + 2 + 4 + 4. Exopod distal segment with 12 long plumose natatory setae.

Second maxilliped ( Figs. 7 B, C). Endopod 4-segmented (incompletely in some individuals) with 0, 1, 3, 3 plumodenticulate setae. Exopod distal segment with 12 long plumose natatory setae.

Third maxilliped ( Fig. 7 D). Incompletely segmented, with 2–3 setae.

Pereiopods ( Fig. 7 D). Chelipeds with sparse setae.

Pleon ( Fig. 6 A, 7E). Pleopod with 0–4 plumose setae.

Telson ( Fig. 7 F). With 2 minute medial dorsal setae.

Megalopa. Size. CL= 0.83 ± 0.03 m; CW= 0.71 ± 0.06 m (n= 9).

Carapace ( Fig. 8 A, B). Longer than broad. Rostrum ventrally deflected with median cleft. With a poorly marked longitudinal medial carina and lateral elevations. Surface with sparsely minute simple setae.

Antennule ( Fig. 8 C). Peduncle 3-segmented, with 4, 1, 1 setae respectively. Endopod absent. Exopod 3- segmented, with 0, 6, and 3 aesthetascs and 0, 2, 2 simple setae, respectively.

Antenna ( Fig. 8 D). Peduncle 3-segmented, with 0, 1, 1 setae, respectively. Flagellum 6-segmented, with 0, 2, 1, 5, 1, 3 setae, respectively.

Mandible ( Fig. 8 E). Palp 2-segmented, with 4 setae on distal segment.

Maxillule ( Fig. 8 F). Protopod with 2 setae. Coxal endite with 11–12 plumose setae. Basial endite with 18–19 (16 + 2–3) plumodenticulate setae. Endopod unsegmented, with 2 proximal and 4 distal setae.

Maxilla ( Fig. 8 G). Coxal endite bilobed, with (8–9) + (4–5) plumodenticulate setae. Basial endite bilobed with 9 + 7 plumodenticulate setae. Endopod unsegmented, with 0–1 seta. Scaphognathite with 37–39 plumose marginal setae and 2 anterior and 1 posterior lateral setae.

First maxilliped ( Fig. 8 H). Epipod with 6 long setae. Coxal endite with 8–9 plumodenticulate setae. Basial endite with 11 plumodenticulate setae. Endopod with 2–4 setae. Exopod 2-segmented, proximal segment with 3 distal plumose setae, distal segment with 5 long terminal plumose setae.

Second maxilliped ( Fig. 8 I). Without epipod. Coxa and basis not differentiated, with 3 setae. Endopod 4- segmented with (0–1), 1, (3–4), (8–9) plumodenticulate setae respectively. Exopod 2-segmented, proximal segment with one seta, distal segment with 5–8 terminal plumose setae.

Third maxilliped ( Fig. 8 J). Epipod elongated with 15 (4 plumose +11 long sparsely plumodenticulate) setae. Coxa and basis not differentiated, with 8–10 setae. Endopod five-segmented, with (8–9), (8–9), 3, 4, (6–7) setae respectively. Exopod two-segmented, proximal segment with one seta and distal segment with 4 long terminal plumose setae.

Pereiopods. All articles well differentiated. Pereiopods 3 and 4 with one coxal process each ( Fig. 9 A). Dactylus of pereiopods 2–4 with 3, 3, 2 spinous setae on inner margin. Dactylus of fifth pereiopod with three long terminal setae and one short terminal spine.

Sternum ( Fig. 9 B). Maxillipeds and cheliped sternites fused with 8 setae. All sternal sutures interrupted medially.

Pleon ( Figs. 9 C, D). Six somites present. Somites 1–6 with (5 + 2), 12, 12, 14, 14, 4 setae respectively. Somites 2–5 each with a pair of biramous pleopods. Somite 6 with a pair of uropods.

Pleopods ( Figs. 9 F–J). Endopod unsegmented, with two terminal hooks, exopod unsegmented with 14, (12– 13), 13, (10–11) long marginal plumose natatory setae respectively. Uropods two-segmented, proximal segment with one segment, and distal segment with 7 long plumose setae respectively.

Telson ( Figs. 9 C–E). Posterior margin rounded, dorsal surface with 6 setae, 2 ventral setae. Zoeal characters frequently appear on the posterior margin (long plumose setae, furcal branches in various degrees of development).

First juvenile (crab stage I). Size: CL= 1.10 ± 0.04 mm; CW= 0.95 ± 0.04 mm; (n= 7).

Carapace ( Fig. 10 A): Longer than broad, quadrangular. Frontal region narrow, measuring slightly less than one-half of carapace width. Anterolateral margins with three teeth, the first being largest, the third smallest.

Antennule ( Fig. 11 A): Peduncle three-segmented, with 7–10, 1, 1 setae respectively. Endopod absent. Exopod 2-segmented, with 0, 3 aesthetascs respectively and 0, 3 setae.

Antenna ( Fig. 11 B): Peduncle three-segmented, with 1–2, 2, 1 setae respectively. Flagellum 5-segmented, with 1, 0, 1, 1, 0 setae respectively; usually the last three segments not completely articulated or fused.

Mandible ( Fig. 11 C). Palp two-segmented, with five setae on distal segment.

Maxillule ( Fig. 11 D). Coxal endite with 12 setae. Basial endite with 18–19 setae. Endopod unsegmented, with 2 proximal and 3 distal setae.

Maxilla ( Fig. 11 E). Coxal endite bilobed with 12 + (3–4) setae. Basial endite bilobed with 7 + 7 setae. Endopod unsegmented, without setae. Scaphognathite with 43–44 plumose marginal setae and 9 lateral setae (8 in one side and 1 in the other side).

First maxilliped ( Fig. 11 F). Epipod with 11–12 long setae. Coxal endite with 13 plumodenticulate setae. Basial endite with 16 plumodenticulate setae. Endopod with 6–7 setae. Exopod 2-segmented, proximal segment with 2 setae, distal segment with 4 long terminal plumose setae.

Second maxilliped ( Fig. 11 G). Coxa and basis undifferentiated, with 1–2 setae. Endopod 4-segmented with 1, 1, (5–6),10 plumodenticulate setae respectively. Exopod 2-segmented, proximal segment with 9 setae and distal segment with 5 terminal plumose setae.

Third maxilliped ( Fig. 11 H). Epipod elongated with 11 plumose + 20 long sparsely plumodenticulate setae. Coxa and basis undifferentiated with plumose 20 setae. Endopod 5-segmented with 17, 14, 7, 5, 7 setae respectively. Exopod 2-segmented, proximal segment with 8 + 1 setae and distal segment with five 5 long terminal plumose setae.

Pereiopods ( Figs. 11 I–L). Pereiopods 3 and 4 without coxal processes. Dactylus of fifth pereiopod with one long plumose subterminal setae.

Pleon ( Fig. 11 M). Six somites present with pleopods without setae. Setation as figured.

Figures

FIGURE 1. Chiromantes ortmanni (Crosnier, 1965). Zoea I. A, lateral view; B, telson; C, antennule; D, antenna; E, maxillule, with detail of coxa; F, maxilla, with detail of coxa; G, first maxilliped; H, second maxilliped. Scale bars of A = 150 µm; of B, G and H = 100 µm; of C – F = 50 µm.

FIGURE 2. Chiromantes ortmanni (Crosnier, 1965). Zoea II. A, lateral view; B, pleon, dorsal view; C, maxillule; D, maxilla. Scale bars of A = 200 µm; of B = 100 µm; of C and D = 50 µm.

FIGURE 3. Chiromantes ortmanni (Crosnier, 1965). Zoea III. A, lateral view; B, pleon; C, antennule; D, antenna; E, maxilla; F, first maxilliped, endopod. Scale bars of A = 250 µm; of B and F = 100 µm; of C – E = 75 µm.

FIGURE 4. Chiromantes ortmanni (Crosnier, 1965). Zoea IV. A, lateral view; B, telson; C, antennule; D, antenna; E, maxillule; F, maxilla; G, first maxilliped, endopod; H, third maxilliped and pereiopods. Scale bars of A = 300 µm; of B and G = 100 µm; of C – F = 75 µm; of H = 150 µm.

FIGURE 5. Chiromantes ortmanni (Crosnier, 1965). Zoea V. A, lateral view; B, telson; C, antennule; D, antenna; E, maxillule; F, maxilla; G, first maxilliped; H, third maxilliped and pereiopods. Scale bars of A = 350 µm; of B = 200 µm; of C – F = 75 µm; of H = 150 µm; of G = 100 µm.

FIGURE 6. Chiromantes ortmanni (Crosnier, 1965). Zoea VI. A, lateral view; B, antennule; C, antenna; D, maxillule; E, maxilla. Scale bars of A = 350 µm; of B = 200 µm; of C – E = 75 µm.

FIGURE 7. Chiromantes ortmanni (Crosnier, 1965). Zoea VI. A, first maxilliped; B, second maxilliped; C, second maxilliped, endopod; D, third maxilliped and pereiopods; E, second pleopod, exopod; F, telson. Scale bars of A – E = 100 µm; of F = 200 µm.

FIGURE 8. Chiromantes ortmanni (Crosnier, 1965). Megalopa. A, dorsal view; B, lateral view; C, antennules; D, antenna; E, mandibular palp; F, maxillule; G, maxilla; H, first maxilliped; I, second maxilliped; J, third maxilliped. Scale bars of A, B and H – J = 200 µm; of C – G = 100 µm.

FIGURE 9. Chiromantes ortmanni (Crosnier, 1965). Megalopa. A, pereiopods 3 and 4, coxa in ventral view; B, sternum ;; C, pleon, dorsal view; D, pleon, lateral view; E, telson, dorsal view; F – I, pleopods 1 – 4; J, uropod. Scale bars = 200 µm.

FIGURE 10. Chiromantes ortmanni (Crosnier, 1965). Juveniles. A, first juvenile, dorsal view; B, carapace shape, crabs I – IX. Scale bars of A = 900 µm; of B = 2 mm.

FIGURE 11. Chiromantes ortmanni (Crosnier, 1965). First juvenile. A, antennule; B, antenna; C, mandible, palp; D, maxillule; E, maxilla; F, first maxilliped; G, second maxilliped; H, third maxilliped; I – L, pereiopods 2 – 5, dactyls; M, pleon, dorsal view. Scale bar = 100 µm.

FIGURE 13. Chiromantes ortmanni (Crosnier, 1965). Juvenile growth from from metamorphosis through the first six crab stages. A, duration (days) of successive stages described with a second-order polynomial regression equation; B, cumulative time of development to successive stages (t, days; transformed to t + 1), logarithmic regression equation.