The complete larval development of Sadayoshia edwardsii (Miers, 1884) (Decapoda: Anomura: Galatheidae) described from laboratory-reared material Author Fujita, Yoshihisa Author Shokita, Shigemitsu text Journal of Natural History 2005 2007-02-21 39 12 865 886 http://dx.doi.org/10.1080/00222930410001671264 journal article 10.1080/00222930410001671264 1464-5262 5214145 Sadayoshia edwardsii ( Miers, 1884 ) ( Figures 1–10 ) First zoea Size. CL 1.29–1.39 mm (mean 1.34 mm ), TL 2.41–2.57 mm (mean 2.46 mm ). Carapace ( Figures 1A , 2A, B ). Typical galatheid larval form; anterodorsal setae absent; anterolateral spine absent; pair of produced, acute spines present posteriorly; posterodorsal margin with 17 or 18 small teeth, posteroventral margin with 20–25 small teeth; rostrum elongated and spine-like, extending to level of anterior apex of the antennal scaphocerite, without distinct lateral teeth but covered with minute denticles; eyes sessile. Figure 1. Sadayoshia edwardsii ( Miers, 1884 ) . (A) First zoea, lateral; (B) second zoea, lateral; (C) third zoea, lateral; (D) fourth zoea, lateral; (E) megalop, carapace, abdomen, telson and pleopods, lateral; (F) megalop, anterior margin of carapace, lateral. Scale bars: 0.5 mm (A, B); 0.1 mm (C–F). Figure 2. Sadayoshia edwardsii ( Miers, 1884 ) . (A) First zoea, carapace, dorsal; (B) first zoea, rostrum, dorsal; (C) second zoea, carapace, dorsal; (D) second zoea, rostrum, dorsal; (E) third zoea, carapace, dorsal; (F) fourth zoea, carapace, dorsal; (G) megalop, entire animal, dorsal; (H) megalop, rostrum, dorsal; (I) megalop, lateral margin of carapace, dorsal; (J) thoracic sternites, ventral. Scale bars: 0.5 mm (A, B); 0.1 mm (C–F). Figure 3. Sadayoshia edwardsii ( Miers, 1884 ) . (A–E) Antennule: (A) First zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) megalop. (F–J) Antenna: (F) first zoea; (G) second zoea; (H) third zoea; (I) fourth zoea; (J) megalop, middle segments omitted. Scale bars: 0.1 mm. Figure 4. Sadayoshia edwardsii ( Miers, 1884 ) , mandible (r, right; l, left). (A) first zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) left mandible of megalop; (F) same, palp. Scale bars: 0.1 mm. Figure 5. Sadayoshia edwardsii ( Miers, 1884 ) , maxillule. (A) First zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) megalop. Scale bars: 0.1 mm. Figure 6. Sadayoshia edwardsii ( Miers, 1884 ) , maxilla. (A) First zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) megalop. Scale bars: 0.1 mm. Figure 7. Sadayoshia edwardsii ( Miers, 1884 ) , first maxilliped (A) First zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) megalop. Scale bars: 0.1 mm. Figure 8. Sadayoshia edwardsii ( Miers, 1884 ) , second maxilliped. (A) First zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) megalop. Scale bars: 0.1 mm. Figure 9. Sadayoshia edwardsii ( Miers, 1884 ) . (A–E) third maxilliped: (A) First zoea; (B) second zoea; (C) third zoea; (D) fourth zoea; (E) megalop (F–K) Pereiopods: (F) Second zoea; (G) third zoea; (H) fourth zoea; (I) megalop, first pereiopod; (J) megalop, second pereiopod, carpus, propodus and dactylus; (K) megalop, fifth pereopod, propodus and dactylus. Scale bars: 0.1 mm. Figure 10. Sadayoshia edwardsii ( Miers, 1884 ) , abdomen and telson. (A) First zoea, abdomen and telson, dorsal; (B) first zoea, posterodorsal margins of fourth and fifth segments, dorsal; (C) first zoea, posterolateral margin of telson, dorsal; (D) first zoea, innermost plumose seta, dorsal; (E) second zoea, fourth and fifth abdominal segments and telson, dorsal; (F) third zoea, sixth abdominal segment, uropod and telson, dorsal; (G) fourth zoea, uropod and telson, dorsal; (H) fourth zoea, first pleopod, ventral; (I) megalop, tail fan, dorsal; (J–M) megalop, first to fourth pleopods, ventral, exopodal plumose setae of second to fourth pleopods truncated. Scale bars: 0.1 mm. Antennule ( Figure 3A ). Uniramous; elongated, with three aesthetascs and three setae terminally and one long plumose seta subterminally. Antenna ( Figure 3F ). Biramous; protopod with one robust serrated spine at distoventral end; endopod fused to protopod, terminally ending in acute spine and with a long plumose seta; scaphocerite with produced, acute spine on distolateral margin, mesial margin with nine plumose setae, ventral and dorsal surfaces with sparse minute denticles. Mandibles ( Figure 4A ). Asymmetrically dentate; incisor processes each with some strong teeth and few small teeth; molar processes strongly serrate or spinose; palp buds absent. Maxillule ( Figure 5A ). Coxal endite with seven plumodenticulate setae; basial endite with two cuspidate and three plumodenticulate setae; endopod unsegmented, with one small proximal seta, one subterminal seta and four terminal setae (setal formula, 1+1+4). Maxilla ( Figure 6A ). Coxal endite bilobed with 8+4 setae; basial endites with 5+4 setae; endopod unsegmented but bilobed, with three distomesial and four distolateral setae (setal formula, 3+4); scaphognathite (exopod) with four marginal plumose setae, posteriorly ending in elongate plumose process. First maxilliped ( Figure 7A ). Coxa with two terminal setae; basis with 12 ventral setae arranged 3+3+3+3; endopod five-segmented, with setation 3, 2, 1, 2, 4+I (I5dorsal plumose setae); exopod two-segmented, distally with four long plumose natatory setae. Second maxilliped ( Figure 8A ). Coxa naked; basis with three setae arranged 1+2, on distoventral margin; endopod four-segmented, with 2, 2, 2, 4+I setae, respectively; exopod as in first maxilliped. Third maxilliped ( Figure 9A ). Small biramous bud; endopod bud sometimes absent. Pereiopods. Absent. Abdomen ( Figures 1A , 10A, B ). Five segments; posterodorsal margins of segments 2–5 each with small but distinct teeth and pair of short plumose setae; segments 4 and 5 each with pair of posterolateral spines; pleopods absent. Telson ( Figures 1A , 10A, C, D ). Trigonal form in dorsal view; dorsal surface covered with numerous, minute denticles; posterior margin deeply concave medially, with 7+7 processes (telsonal formula; I+ii+3–7), first (lateralmost) immovable spine, second short plumose seta (5anomuran hair), third to seventh bearing long, stout plumose setae with minute denticles. Colour in life. Carapace, abdomen including telson and appendages essentially transparent; median gastric region and ventral side of abdominal segments bright orange; red or brightorange chromatophores present on lateral margin of carapace, eyes, mandibles, maxillule, maxilla, and basis and endopod of first and second maxillipeds. Second zoea Size. CL 1.53–1.70 mm (mean 1.63 mm ), TL 3.04–3.23 mm (mean 3.14 mm ). Carapace ( Figures 1B , 2C, D ). Posterodorsal and posteroventral margins with 8–12 and 26–29 teeth, respectively; three pairs of setae present on proximal part of rostrum and median part of carapace; basal part of rostrum swollen; eyes now stalked; otherwise unchanged. Antennule ( Figure 3B ). Protopod with two or three plumose setae present at distal onequarter, distally with four aesthetascs and three or four simple setae; endopodal bud slightly developed, with a terminal plumose seta. Antenna ( Figure 3G ). Protopod with additional serrate spine at distoventral end; endopod developed, with one short plumose seta; scaphocerite with 11 or 12 (usually 12) plumose setae on mesial margin. Mandible ( Figure 4B ). Unchanged. Maxillule ( Figure 5B ). Basial endite with four cuspidate and three plumodenticulate setae; otherwise unchanged. Maxilla ( Figure 6B ). Distal lobe of basial endite with five or six (usually six) setae; scaphognathite with six or seven (usually seven) plumose setae on anterior margin and one elongate plumose process at posterior apex; otherwise unchanged. First maxilliped ( Figure 7B ). Exopod with seven natatory setae; otherwise unchanged. Second maxilliped ( Figure 8B ). Exopod with seven natatory setae; otherwise unchanged. Third maxilliped ( Figure 9B ). Endopod more developed than in previous stage, naked or with one terminal seta; exopod with six natatory setae. Pereiopods ( Figure 9F ). Unsegmented buds. Abdomen ( Figures 1B , 10E ). Posterodorsal minute teeth disappeared; otherwise unchanged. Telson ( Figures 1B , 10E ). Posterior margin with 8+8 processes (telsonal formula, I+ii+3–8); two pairs of short setae present at posterodorsal surface. Colour in life. Similar to first zoea, but antennule and third maxilliped with red or brightorange chromatophores. Third zoea Size. CL 2.00– 2.15 mm (mean 2.06 mm ); TL 3.90–4.13 mm (mean 3.97 mm ). Carapace ( Figures 1C , 2E ). Posterodorsal and posteroventral margins of carapace with four to nine and 15–18 teeth, respectively; otherwise unchanged. Antennule ( Figure 3C ). Protopod swollen proximally, with one short plumose seta, one lateral plumose seta present at mid-length of lateral margin, four plumose setae present at junction with exopod; endopod developed, but still fused to protopod, bearing one long plumose seta terminally; exopod articulated, with two lateral aesthetascs, terminally with three aesthetascs and three setae. Antenna ( Figure 3H ). Endopod more developed than in previous stage; mesial margin of scaphocerite with 14 or 15 plumose setae; otherwise unchanged. Mandible ( Figure 4C ). Appearance of palp bud; otherwise unchanged. Maxillule ( Figure 5C ). Coxal endite with eight plumodenticulate setae; basial endite with five cuspidate and three plumodenticulate setae; otherwise unchanged. Maxilla ( Figure 6C ). Coxal endite with 9–10+5 setae; basial endite with 6–7+8–9 setae; scaphognathite with 12–14 plumose setae on lateral margin, one plumose seta on inner margin and one posterior plumose process; otherwise unchanged. First maxilliped ( Figure 7C ). Setation of endopod 3, 2+I, 1+I, 2, 4+I; exopod with eight natatory setae; otherwise unchanged. Second maxilliped ( Figure 8C ). Setation of endopod 2, 2+I (dorsal plumose seta rarely absent), 2+I, 4+I; exopod with eight natatory setae; otherwise unchanged. Third maxilliped ( Figure 9C ). Endopod more developed than in previous stage, with one terminal seta; exopod with seven or eight (usually eight) natatory setae. Pereiopods ( Figure 9G ). Chela bilobed; more developed than in previous stage. Abdomen ( Figures 1C , 10F ). Six segments; segment 6 with one dorsal and one ventral posteromedian spine, and with pairs of posterolateral spines; appearance of biramous uropods, endopods naked, exopods well developed, with nine or 10 plumose setae marginally and two small setae at ventral surface. Telson ( Figures 1C , 10F ). Posterior processes still 8+8, but fourth paired processes now robust, fused spines, with numerous minute spinules on surface (telsonal formula, I+ii+3+IV+5–8); three pairs of short setae on posterodorsal surface. Colour in life. Almost as in previous stage, but chromatophores on antennule sometimes absent. Fourth zoea Size. CL 2.40–2.70 mm (mean 2.54 mm ), TL 4.85–5.15 mm (mean 4.98 mm ). Carapace ( Figures 1D , 2F ). Posterodorsal and posteroventral margins of carapace with three to six and 8–20 (mostly 9–11) small teeth, respectively; otherwise unchanged. Antennule ( Figure 3D ). Protopod with two short plumose setae at proximal part, two or three lateral plumose setae on middle part, four plumose setae at junction with exopod, and one long plumose seta directly proximal to endopod; endopod developed, terminal plumose seta disappeared; exopod with five rows of lateral aesthetascs, numbering proximal to distal 2–3, 5, 3, 3, 2, respectively, distal apex with three aesthetascs and two or three setae. Antenna ( Figure 3I ). Endopod well developed; mesial margin of scaphocerite with 16–18 plumose setae; otherwise unchanged. Mandible ( Figure 4D ). Palp developed, but unsegmented. Maxillule ( Figure 5D ). Coxal endite with nine plumodenticulate setae; basial endite with seven cuspidate and three plumodenticulate setae; otherwise unchanged. Maxilla ( Figure 6D ). Coxal endite with 10–12+5 setae; basial endite with 8–10+10–12 setae; scaphognathite with 20–23 plumose setae on lateral margin, three or four plumose setae on mesial margin and one posterior plumose process; otherwise unchanged. First maxilliped ( Figure 7D ). Unchanged. Second maxilliped ( Figure 8D ). Unchanged. Third maxilliped ( Figure 9D ). Endopod well developed, indistinctly two-segmented, with two or three setae; otherwise unchanged. Pereiopods ( Figure 9H ). Well formed, but unsegmented; first and fifth pereiopods bilobed as chelipeds. Abdomen ( Figures 1D , 10G, H ). Segment 6 with pair of small dorsal-posterolateral setae; appearance of biramous pleopods on segments 2–5; uropods segmented, endopod with seven to nine marginal plumose setae plus one dorsal short seta, exopod with 11–14 plumose setae and one spine marginally, four short setae on ventral surface; otherwise unchanged. Telson ( Figures 1D , 10G ). Longer than broad; posterior processes 9+9 (telsonal formula, I+ii+3+IV+5–9); four pairs of short setae present on dorsal surface. Colour in life. Similar to third zoea. Megalop (decapodid). Size. PCL 1.05–1.18 mm (mean 1.11 mm ), CL 1.88–2.14 mm (mean 2.02 mm ), TL 3.60–3.95 mm (mean 3.80 mm ). Carapace ( Figures 1E, F , 2G, H, I, J ). Longer than broad; dorsal surface with numerous setae, lateral margin with six or seven (usually seven) small spines, three sublateral spines on hepatic to epibranchial regions, pair of epigastric spines present; transverse striae indistinct. Rostrum triangular, broad proximally, with three lateral teeth, anterior tooth distinctly smaller than the posterior teeth. Pterygostomian flap differentiated from the carapace by faint demarcations, anterior margin armed with two spines. Thoracic sternites as illustrated; third thoracic sternite approximately three times as wide as long, anteromedian margin concave; following sternites expanded laterally, without distinct transverse striae or ridges, sparsely setose as illustrated. Antennule ( Figure 3E ). Biramous; peduncle three-segmented, proximal segment with three large, acute spines, penultimate segment with some short setae, ultimate segment with three pairs of long plumose setae terminally; endopod three-segmented, proximal segment with one or two setae, penultimate segment with three setae, ultimate segment with four or five subterminal and three terminal setae; exopod six-segmented, first segment naked, second to fifth segments with seven rows of marginal aesthetascs arranged 5–6, 5–6+5–6, 3+3, 2+1 (from proximal to distal), ultimate segment with two or three setae. Antenna ( Figure 3J ). Peduncle four-segmented; flagellum with 21–25 articles, each with zero to five setae distally, terminal segment with five subterminal and three terminal setae. Mandible ( Figure 4E, F ). Subsymmetrically scoop-like process; palp three-segmented, proximal segment with two setae, ultimate segment with 14–16 stout, serrate setae distally. Maxillule ( Figure 5E ). Coxal endite with 30–33 plumodenticulate setae, lower part with four long setae; basial endite with 16–20 cuspidate and 11–15 setae, and two plumose seta and one long seta externally proximal to endopod; endopod unsegmented, with one or two setae. Maxilla ( Figure 6E ). Coxal and basial endites bilobed, setation highly variable, with 43– 47+14–18 and 17–23+28–32 setae, respectively; endopod unsegmented, with one or two small proximal and one or two subterminal setae; scaphognathite with 43–48 plumose setae marginally plus six or seven setae on surface. First maxilliped ( Figure 7E ). Coxal and basial endites with 14–18, 29–32 setae on ventral margin, respectively; endopod unsegmented, naked or with one terminal seta; exopod with one or two plumose setae on lateral median part and one to five subterminal/terminal setae. Second maxilliped ( Figure 8E ). Coxa with three setae; basis with five or six setae; endopod five-segmented (proximal segment fused to basis), with setation 4–6, 4–5, 4–5, 12–14, 15– 19 (including stout serrate setae on distal segment); exopod segmented, proximal segment with six to nine simple/plumose setae marginally, distal segment with 10–13 terminal simple/plumose setae. Third maxilliped ( Figure 9E ). Coxa and basis with 12 or 13 and four to six setae, respectively; endopod five-segmented, ischium with crista dentata of 12–17 small teeth and four to seven setae; merus with five to seven setae; carpus, propodus and dactylus with 20– 24, 41–48, 29–36 setae (including stout serrate setae), respectively; exopod segmented, proximal segment with three or four setae marginally, distal segment with 10–12 terminal simple/plumose setae. Pereiopods ( Figure 9I, J, K ). All pereiopods fully developed, segmented. Cheliped (first pereiopod) robust, approximately as long as carapace, sparsely setose and spinose as illustrated; carpus with one large acute spine on mesial margin. Ambulatory legs (second to fourth pereiopods) slender, sparsely setose as shown; merus with row of small teeth on extensor and flexor margins; carpus with one large, acute spine and few small spines on extensor margin; propodus with four to six movable spines on flexor margin, distal pair largest; dactylus with four to five movable spines and four to six teeth. Fifth pereiopod short, subcylindrical, chelate; palm with three to five long and some short serrate setae. No male/female gonopores. Abdomen ( Figure 1E , 2G ). Six segments, sparsely setose on dorsal surface as illustrated; biramous pleopods present on segments 2–5 ( Figure 10J–M ), endopods increasing in length posteriorly, with two to four small terminal hooks, exopods well developed, bearing terminal plumose setae, setal formulae progressing posteriorly with 11–12, 11–12, 11–12, 11–12. Tail fan ( Figures 1E , 10I ). Telson incompletely divided into five plates with faint demarcations; anterolateral plate more distinctly marked than others; posterior margin with 16– 19 long plumose setae (frequently eight or nine pairs, but sometimes asymmetrical) on posterior margin and one or two spinules on each posterolateral margin, dorsal and ventral surfaces with short plumose setae as illustrated; uropods biramous, endopod with 17–19 plumose setae marginally, dorsal surface with 9–11 short setae and four to six small spines, exopod with 17–29 (mostly 21–24) long plumose setae marginally, dorsal surface with two short setae and four to seven small spines on posterior part. Colour in life. Carapace and abdomen generally transparent, with scattered, orange or/and red chromatophores; telson with red chromatophores on posterolateral margin; appendages essentially transparent, red or bright-orange chromatophores present on eye stalk, antennal peduncle, second and third maxillipeds, chela of first pereiopod, dactyli and propodi of second to fourth pereiopods, and uropods.