Eriocheir sinensis H. Milne Edwards, 1853

Kamanli, Seyit A., Morritt, David, Ball, Alexander D., Goral, Tomasz & Clark, Paul F., 2018, Re-description of Chinese mitten crab Eriocheir sinensis H. Milne Edwards, 1853 (Crustacea: Brachyura: Grapsoidea: Varunidae) zoeal development using confocal laser scanning microscopy, Zootaxa 4507 (1), pp. 1-67 : 6-20

Eriocheir sinensis H. Milne Edwards, 1853

Figs. 1 ̄ 52

Schnakenbeck 1926: 352, fig. (ZI), 1933: 157, figs. 46̅66 (PZ, ZI); Hinrichs & Grell 1937: 217, Abb. 1̅3 (ZV); Buhk 1938: 776, Abb. 3̅5 (ZI̅V); Panning 1939a: 273, Abb. 1̅11 (ZI̅IV), 1939b: 361, fig. 2 (ZI); André 1947: 35, figs. 2̅5 (ZI,); Liang et al. 1974: 67, figs. 1̅63 (ZI̅V); Ingle 1986: 101, fig. 1 (ZI), 1991: 248̅250, figs. 1.10n; 1.14d; 1.18f; 1.22g; 1.23e; 1.29f; 1.32g; 1.35c; 1.36k; 1.38g; 2.37d̅j; 2.38, (ZI-V); Kim & Hwang 1995: figs. 1̅7, tabs. III̅IV (ZI̅V); Montú et al. 1996: 50, figs. 1̅16 (PZ, ZI̅VI).

Zoea I ( Figs. 1A, 2−9)

Carapace ( Fig. 1A, 2): Globose; dorsal spine present, gently curved, longer than rostral and lateral spines; rostral spine present and shorter than dorsal spine and with small spinules; lateral spines present with small spines on surface; anterodorsal setae absent; one pair of posterodorsal setae present; ventral margin with 8¯9 serrations, setae absent; dorsoposterior margin without setae; eyes sessile.

Antennule ( Fig. 3A): Primary flagellum with 4 terminal aesthetascs (2 broad, 2 slender) and 1 small seta; accessory flagellum absent.

Antenna ( Fig. 3B): Uniramous; protopod distally bilaterally spinulate; endopod absent; exopod short, ca. 30% of protopod, with 2 unequal (1 short, 1 minute) medial spines.

Mandible ( Fig. 4A, B): Palp absent, incisor teeth distinct.

Maxillule ( Fig. 4C): Uniramous; epipod seta absent; coxa with 5 sparsely plumose setae, basial endite with 5 armed processes (four plumodenticulate, one sparsely plumose setae); endopod comprising 2 articles, proximal article with 1 seta, distal article with 5 (1 subterminal+4 terminal) plumose setae; exopod absent.

Maxilla ( Fig. 5): Biramous; coxal endite bilobed with 4+3 plumose setae; basial endite bilobed with 5+4 sparsely plumose setae; endopod without articulation and bilobed with 2+2 plumose setae; exopod (scaphognathite) margin with 4 plumose+1 long distal stout process.

First maxilliped ( Fig. 6): Biramous; coxa without seta; basis with 10 (2+2+3+3) setae; endopod comprising 5 articles with 2,2,1,2,5 (1 subterminal (dorsal)+4 terminal) setae; exopod comprising 2 articles, distal article with 4 long terminal plumose natatory setae.

Second maxilliped ( Fig. 7): Biramous; coxa without seta; basis with 4 (1+1+1+1) sparsely plumose setae; endopod comprising 3 articles with 0,1,6 (3 subterminal (1 dorsal, 2 ventral)+3 terminal) sparsely plumose setae; exopod comprising 2 articles, distal article with 4 terminal plumose natatory setae.

Third maxilliped: Absent.

Pereiopods: Absent.

Pleon ( Fig. 8): Five pleomeres, pleomere 2 with 1 pair of dorsolateral processes directed anteriorly; pleomeres 3 and 4 each with a small pair of dorsolateral processes directed ventrally, pleomere 1 with rounded posterolateral process; pleomeres 2¯4 with dorsolateral processes; pleomere 1 without medial setae; pleomeres 2¯5 with a pair of posterodorsal setae; pleopods absent.

Telson ( Fig. 9): Bifurcated; each fork long curved distally with an inner row of paired spinules; lateral and dorsomedial spines absent; posterior margin with 3 pairs of stout spinulate setae, inner pair with 2 long spinules medially on inner margin; anal operculum ventral.

Zoea II ( Figs. 1B, 10−15)

Carapace ( Fig. 1B, 10): Two pairs of anterodorsal (one pair on orbital margin) setae; lateral spines now smooth; ventral margin with 2 anterior plumose setae and 2 posterior setae with additional serrations; eyes stalked. Otherwise unchanged.

Antennule ( Fig. 11A): Primary flagellum with 4 broad aesthetascs and 2 equal short setae. Otherwise unchanged.

Antenna ( Fig. 11B): Exopod more developed, ca. 35% of protopod length. Otherwise unchanged.

Mandible: Unchanged.

Maxillule ( Fig. 11C): Biramous; basial endite with 7 armed processes; exopod, plumose seta present. Otherwise unchanged.

Maxilla ( Fig. 12): Exopod (scaphognathite) margin with 5+3 plumose setae; long distal stout process reduced in size. Otherwise unchanged.

First maxilliped ( Fig. 13): Exopod, distal article with 6 long terminal plumose natatory setae. Otherwise unchanged.

Second maxilliped ( Fig. 14): Exopod, distal article with 6 long terminal plumose natatory setae. Otherwise unchanged.

Third maxilliped: Absent.

Pereiopods: Absent.

Pleon ( Fig. 15 A–C): Pleomere 1 with 1 small dorsal medial seta. Otherwise unchanged.

Telson ( Fig. 15D): Unchanged.

Zoea III ( Figs. 1C, 16 ̄22)

Carapace ( Fig. 1C, 16): Now with four pairs of anterodorsal setae; dorsal spine with 1 pair of setae; lateral spine slightly decreasing in length; ventral margin 2 anterior plumose setae and 4 posterior setae and with additional serrations. Otherwise unchanged.

Antennule ( Fig. 17A): Unchanged.

Antenna ( Figs. 17B, C): Biramous; endopod present as small bud (ca. 20% of whole appendage); exopod more developed, ca. 40% of protopod. Otherwise unchanged.

Mandible ( Fig. 18A): Unchanged.

Maxillule ( Fig. 18B): Epipod seta present; Otherwise unchanged.

Maxilla ( Fig. 19): Coxal endite with 5+3 plumose setae; basial endite with 6+5 sparsely plumose setae; exopod (scaphognathite) margin with 9+6 plumose setae. Otherwise unchanged.

First maxilliped ( Fig. 20): Endopod with 2,2,2 (now with a dorsal seta),2,5 (1 subterminal+4 terminal) setae; exopod, distal article with 8 long terminal plumose natatory setae. Otherwise unchanged.

Second maxilliped ( Fig. 21): Exopod, distal article with 8 terminal plumose natatory setae. Otherwise unchanged.

Third maxilliped: Absent.

Pereiopods: Absent.

Pleon ( Fig. 22 A-C): Pleomere 1 with 1 or 2 medial setae. Pleomere 6 now differentiated. Otherwise unchanged.

Telson ( Fig. 22A, D): Posterior margin with 4 pairs of setae (4+4), additional inner pair of inner sometimes represented by a single seta (4+3). Otherwise unchanged.

Zoea IV ( Figs. 1D, 23−32)

Carapace ( Figs. 1D, 23−24): Dorsal spine with 2 pairs of setae; now with 5 pairs of anterodorsal setae; lateral spine shorter in length than previous stage; 4 anterior plumose setae and 7¯8 posterior setae on ventral margin with additional serrations on each side; 3 pairs of setae on dorsoposterior margin. Otherwise unchanged.

Antennule ( Fig. 25A): Primary flagellum with 1 proximal and 1 distal subterminal aesthetasc and 3 long terminal aesthetascs and 1 short terminal seta. Otherwise unchanged.

Antenna ( Fig. 25B): Endopod now more developed (ca. 30% of whole appendage); exopod now more developed, ca. 40̄50%. Otherwise unchanged.

Mandible ( Fig. 26): Well developed, molar now present.

Maxillule ( Fig. 27): Coxa with 7 highly plumose and 1 simple setae, basial endite with 11 armed processes (marginal), 1 plumose and 1 short simple setae on inner margin of basal endite. Otherwise unchanged.

Maxilla ( Fig. 28): Coxal endite bilobed with 7+3 plumose setae and 1 distal simple seta; basial endite with 8+8 sparsely unequal plumose setae; exopod (scaphognathite) margin with 18+7 highly plumose setae of various length. Otherwise unchanged.

First maxilliped ( Fig. 29): Coxa with 1 seta; endopod with 2,3 (1 dorsal, 2 ventral setae),2,2,6 (2 subterminal (1 dorsal+1 ventral)+4 terminal) setae, variation of article 2 with occasionally only 2 (1 dorsal, 1 ventral) setae; exopod, distal article with 10 long terminal plumose natatory setae. Otherwise unchanged.

Second maxilliped ( Fig. 30): Exopod, distal article with 10 terminal plumose natatory setae. Otherwise unchanged.

Third maxilliped ( Fig. 31A): Present; biramous; epipod present; endopod longer than exopod.

Pereiopods ( Fig. 31B): Present; bilobed cheliped; walking legs with some articulation.

Pleon ( Fig. 32 A-D): Pleomere 1 with 5 medial setae; pleopods present on pleomeres 2¯6, uniramous, endopods absent. Otherwise unchanged.

Telson ( Fig. 32E): Posterior margin with 5 pairs setae; no variation recorded. Otherwise unchanged.

Zoea V ( Figs. 1E, 33−42)

Carapace ( Figs. 1E, 33−34): Dorsal spine with 3 pairs of setae; lateral spine shorter than previous stage; now with 7 pairs of anterodorsal setae; 16¯17 plumose posterior setae on ventral margin with additional spines on each side. Otherwise unchanged.

Antennule ( Fig. 35A, B): Basal region shaped as convex with 2 simple setae; primary flagellum with 4 proximal subterminal long aesthetascs; 5 distal subterminal aesthetascs and 5 terminal aesthetascs + 1 simple seta; accessory flagellum present as small bud. Otherwise unchanged.

Antenna ( Fig. 35C, D): Protopod distally bilaterally spinulate; endopod now clearly discrete (ca. 60% of whole appendage), exopod more developed and occasionally with only 1 seta instead of 2. Otherwise unchanged.

Mandible ( Fig. 36): Palp present, with additional incisor teeth. Otherwise unchanged

Maxillule ( Fig. 37): 2 epipod setae; coxa with 3 tiers, 9 armed processes (marginal) setae+4 plumose setae+3 simple setae respectively; basial endite now with 16 armed processes (marginal) and 4 simple setae on inner margin. Otherwise unchanged.

Maxilla ( Fig. 38): Coxal endite with 11+4 plumose setae; basial endite with 10+11 sparsely unequal plumose setae; exopod (scaphognathite) margin now with 32¯33 highly plumose setae of various length + 1 lateral seta. Otherwise unchanged.

First maxilliped ( Fig. 39): Coxa with epipod lobe with either 3 setae or 3 setae and 1 small seta; basis with 10–12 (2+2+3+3 or 2+3+4+3 respectively) setae; endopod normally 2,3 (1 dorsal+2 ventral setae),2,2,6 (2 subterminal (1 dorsal+1 ventral)+4 terminal) setae, variation in article 1 with occasionally 1 seta; exopod, distal article with 12–13 long terminal plumose natatory setae. Otherwise unchanged.

Second maxilliped ( Fig. 40): Endopod with either 0,1,6 (2 subterminal (1 dorsal+1 ventral)+4 terminal) or 0,1,7 (3 subterminal (1 dorsal+2 ventral)+4 terminal) sparsely plumose setae; exopod with 12–13 terminal plumose natatory setae. Otherwise unchanged.

Third maxilliped ( Fig. 41A): Endopod with articulation; 2 gills present (podobranch and arthrobranch).

Pereiopods ( Fig. 41B): Cheliped more distinct; some articulation; 3 developed gill buds (podobranchs or arthrobranchs?).

Pleon ( Figs. 41C, 42A, C): Pleomere 1 with 7 medial setae of variable lengths; pleopods on pleomeres 2¯5 much more developed, biramous with endopod buds, pleopod (uropod) on somite 6 much smaller than on somites 2̄5 and endopod bud absent. Otherwise unchanged.

Telson ( Fig. 42): Now with 5 pairs (4 long, 1 small) setae on posterior margin and 1 pair of dorsal medial setae; with 1 pair of medial setae. Otherwise unchanged.

Zoea VI ( Figs. 1F, 43−52)

Carapace ( Figs. 1F, 43): Dorsal spine with 4 pairs of setae; with 9 pairs of anterodorsal setae; 4¯5 pairs of setae on dorsoposterior margin. Otherwise unchanged.

Antennule ( Fig. 44): 5 proximal subterminal aesthetascs; 5 distal subterminal aesthetascs and 6 terminal aesthetascs; accessory flagellum now more developed but without setae. Otherwise unchanged.

Antenna ( Fig. 45): Endopod now with signs of articulation and clearly discrete (ca. 75% of whole appendage) with protuberances distally, endopod almost equal with protopod; exopod slightly longer than previous stage, ca. 60% of protopod with 1 distinct seta. Otherwise unchanged.

Mandible ( Fig. 46): Palp more developed. Otherwise unchanged.

Maxillule ( Fig. 47): 3 epipod setae; coxa with 3 tiers, 10 armed processes (marginal) setae + 4 plumose setae + 3 simple setae respectively. Otherwise unchanged.

Maxilla ( Fig. 48): Coxal endite with 12+6 plumose setae; basial endite with 10+11 sparsely unequal plumose setae; exopod (scaphognathite) margin with 44 highly plumose setae of various length. Otherwise unchanged.

First maxilliped ( Fig. 49): Coxa with 3 long setae 1 simple setae on developing epipodal bud, 1 epipod with podobranch gill; basis with 12 (2+2+4+1+3) setae; endopod article 2 with only 2 (1 dorsal+1 ventral) setae and no variation; exopod, distal article with 14 long terminal plumose natatory setae. Otherwise unchanged.

Second maxilliped ( Fig. 50): Coxa developing epipodal bud present; exopod with 13 terminal plumose natatory setae. Otherwise unchanged.

Third maxilliped ( Fig. 51A): Endopod and exopod more developed. Otherwise unchanged.

Pereiopods ( Fig. 51B): More developed than previous stage and with four gill buds. Otherwise unchanged.

Pleon ( Fig. 51C, 52 A–C): Pleopods now more developed. Otherwise unchanged.