Coenobita violascens Heller 1862
Creators: name: Kato, Saori
name: Hamasaki, Katsuyuki
name: Dan, Shigeki
name: Kitada, Shuichi
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Coenobitidae
Coenobita
Coenobita violascens

description: Coenobita violascens Heller, 1862
(Figs. 1–7)
First zoea
Size. CL = 1.23 ± 0.04 (1.16–1.29) mm; TL = 2.58±0.08 (2.45–2.69) mm; N = 10.
Intermoult period. 4.0 ± 0.2 (3–5) days; N = 57.
Carapace (Fig. 1 A, F). Rostrum tapered, long, extending beyond the tips of antennules, faintly carinate; posterolateral margins of carapace rounded; eyes sessile.
Antennule (Fig. 2 A). Uniramous, unsegmented, with 3(2) terminal aesthetascs, 3 terminal setae and long subterminal seta.
Antenna (Fig. 2 B). Biramous; protopod with serrated spine distally at base of exopod; endopod unsegmented, fused to protopod, with 2 long and 1 short terminal setae; exopod (scaphocerite) with 10 setae on mesial and distal margins, spine on outer distal margin and fine setules on inner margin.
Mandible (not illustrated). Asymmetrical dentate; palp bud absent.
Maxillul e (Fig. 2 C). Coxal endite with 7(5) setae; basal endite with 2 strong denticulate spines and 2 setae; endopod 3-segmented, distal segment with 2 terminal setae.
Maxilla (Fig. 2 D). Coxal endite bilobed, with 6–7+3–4 setae; basal endite bilobed, with 4–5+3–4 setae; endopod bilobed, with 2+1–2 setae and fine setules on outer margin; exopod (scaphognathite) margin with 4–5 plumose setae and fine setules on inner margin.
First maxilliped (Fig. 2 E). Coxa naked; basis with hook-like process plus 2 fine setae at proximal end of inner face and with 6–8 ventral setae arranged 1 + 1+2–3+2–3; endopod 5-segmented, with 3, 2, 1, 2, 4+ I setae (Roman numeral denoting dorsolateral seta), first 3 segments with some setules; exopod incompletely 2-segmented, with 4 terminal natatory plumose setae.
Second maxilliped (Fig.2 F). Coxa without seta; basis with 3 (2) setae arranged 1+2 (1); endopod 4-segmented, with 2, 2, 2 (1), 4 (3)+ I setae, 2nd and 3rd segments with some setules; exopod as in first maxilliped.
Third maxilliped (Fig.2 G). Two-segmented uniramous bud.
Pleon (Fig.1 A, F). With 5 pleomeres; pleomere 2 with conspicuous, slightly curved mediodorsal spine; pleomeres 3 and 4 each with small mid-dorsal spinule; pleomere 5 with large mid-dorsal spine and pair of large posterolateral spines.
Telson (Fig. 2 H). With 7+7 marginal processes, outermost (1st) fixed spine, 2nd fine seta, 3rd–7th setae; posteromedian notch semicircular; very short marginal setae between processes and on median notch.
Second zoea
Size. CL = 1.47 ± 0.08 (1.33–1.56) mm; TL = 3.16 ± 0.12 (2.93–3.27) mm; N = 10.
Intermoult period. 3.3 ± 0.5 (2–4) days; N = 57.
Carapace (Fig. 1 B, G). More noticeable rostral carina; eyes stalked; otherwise unchanged.
Antennule (Fig. 3 A). Uniramous, with 3 (2) terminal aesthetascs, 4 terminal setae and 1 long and 1–2 short subterminal setae.
Antenna (Fig. 3 B). Protopod with small spine near junction of scaphocerite; otherwise unchanged.
Mandible (not illustrated). Essentially unchanged.
Maxillule (Fig. 3 C). Coxal endite with 6–7 setae; basal endite with 4 strong denticulate spines; otherwise unchanged.
Maxilla (Fig. 3 D). Coxal endite with 6–7 + 3–4 setae; basal endite with 4–5 + 4 setae; endopod with 2 + 2 setae; scaphognathite with 5–8 marginal plumose setae.
First maxilliped (Fig.3 E). Basis with 7–8 setae arranged 1 + 1+3+2–3; endopod with 2–3+ I, 1–2 + I, 1+ I, 2, 4 + I setae; exopod with 6 terminal natatory plumose setae.
Second maxilliped (Fig. 3 F). Basis with 3 setae arranged 1 + 2; endopod with 2, 2+ I, 2 + I, 4 + I setae; exopod as in 1st maxilliped.
Third maxilliped (Fig. 3 G). Endopod bud with small terminal seta; exopod 2-segmented, with 5 terminal natatory plumose setae.
Pereiopods. Small buds visible.
Pleon (Fig. 1 B, H). Unchanged.
Telson (Fig. 3 H). With 8 +8 processes including additional pair of setae; median notch indistinct.
Third zoea
Size. CL = 1.89 ± 0.04 (1.82–1.94) mm; TL = 3.99 ± 0.11 (3.73–4.11) mm; N = 10.
Intermoult period. 3.4 ± 0.5 (3–4) days; N = 57.
Carapace (Fig. 1 C, H). Essentially unchanged.
Antennule (Fig. 4 A). Protopod with 2 long setae at base of endopod and 2–3 setae on opposite side; endopod as a small bud with 1 long seta; exopod with 2–3 terminal aesthetascs and 3 terminal setae.
Antenna (Fig. 4 B). Endopod articulated with protopod, bearing terminal seta; scaphocerite with 13–14 setae; otherwise unchanged.
Mandible (not illustrated). Essentially unchanged.
Maxillule (Fig. 4 C).Coxal endite with 7–8 setae; otherwise unchanged.
Maxilla (Fig. 4 D). Scaphognathite with 10–11 marginal plumose setae; otherwise unchanged.
First maxilliped (Fig. 4 E). Endopod with 3+ I, 2 + I, 1 + I, 2, 4 + I setae; otherwise unchanged.
Second maxilliped (Fig. 4 F).Unchanged.
Third maxilliped (Fig. 5 G). Exopod with 6 terminal natatory plumose setae; otherwise unchanged.
Pereiopods. Four obvious buds.
Pleon (Figs. 1 C, H, 4H). With 6 pleomeres; armature of pleomeres 2–5 unchanged; pleomere 6 with a mediodorsal spine.
Uropods (Fig. 4 H). Exopod, endopod and protopod fused; endopods naked, much smaller than exopod; exopod with 8 setae along posterior and inner margins and fine setules on mesial margin.
Telson (Fig. 4 H). With 8 + 1 +8 processes; a short median seta flanked by 8 processes; outermost (1st) fixed spine, 2nd fine seta, 3rd seta, 4th larger fixed spine, 5th–8th setae.
Fourth zoea
Size. CL = 2.29 ± 0.10 (2.11–2.45) mm; TL = 4.84 ± 0.12 (4.65–5.00) mm; N = 10.
Intermoult period. 5.7 ± 0.5 (5–7) days; N = 57.
Carapace (Fig. 1 D, I). Unchanged.
Antennule (Fig. 5 A). Protopod with mesial seta, 4 long setae at base of endopod and 3–4 setae on opposite side; endopod bud developed; exopod with mesial seta, 3 terminal aesthetascs and 4 terminal setae.
Antenna (Fig. 5 B). Endopod 2-segmented, almost as long as exopod; scaphocerite with 14–16 setae; otherwise unchanged.
Mandible (Fig. 5 C). Palp bud present.
Maxillule (Fig. 5 D). Coxal endite with 8 setae; basal endite with 6 strong denticulate spines and 2 setae; endopod 3-segmented, 2nd segment with 0–1 seta and distal segment with 2 setae.
Maxilla (Fig. 5 E). Coxal endite with 8–9+ 4 setae; basal endite with 4–5 4–5 setae; endopod with 2 +2 setae; scaphognathite with 13–15 marginal plumose setae on distal lobe.
First maxilliped (Fig. 5 F). Unchanged.
Second maxilliped (Fig. 5 G). Exopod with 8 (7) terminal natatory plumose setae; otherwise unchanged.
Third maxilliped (Fig. 5 H). Unchanged.
Pereiopods. Five buds present.
Pleon (Fig. 1 D, I). Pleomeres 2–5 with pleopod buds (Fig. 5 J); otherwise unchanged.
Uropods (Fig. 5 I). Exopod, endopod and protopod articulated; endopod with 6–7 setae and inner marginal row of fine setules; exopod with sharp posterolateral marginal process, 11–12 setae along posterior and inner margins and fine setules on inner margin.
Telson (Fig. 5 I). Unchanged.
Megalopa
Size. CL = 1.58 ± 0.10 (1.45–1.77) mm; TL = 4.24 ± 0.18 (4.01–4.60) mm; N = 10.
Duration from hatching to the megalopal stage. 16.4 ± 0.8 (15–19) days; N = 57.
Carapace (Fig. 1 E). Shorter than pleon, including telson; rostrum rounded, extending beyond front; eyes and eyestalks well developed.
Antennule (Fig. 6 A). Biramous; peduncle 3-segmented, each segment with some setae; endopod unsegmented, with mesial seta and 2–4 terminal setae; exopod unsegmented, with a total of 8 aesthetascs and 1 mesial and 2–4 terminal setae.
Antenna (Fig. 6 B). Peduncle 5-segmented; supernumerary segment present; acicle rounded knob with dorsal seta; flagellum with 7 articles, setal formula 0, 0–2, 2–4, 0–1, 3–4, 2 (3), 5–8.
Mandible (Fig. 6 C). Reduced and simplified; palp 3-segmented, 1st segment with 0–1 setae and distal (3rd) segment with 7–9 setae.
Maxillule (Fig. 6 D). Coxal endite with 14–16 setae; basal endite with 10–14 setae and 12–16 spinules; endopod unsegmented, with well-developed, recurved external lobe, internal lobe with 2 setae on inner margin.
Maxilla (Fig. 6 E). Coxal endite with 25–29 (not all illustrated) + 5–6 setae; basal endite with 6–9 + 10–12 setae; endopod unsegmented, with 0–2 setae; scaphognathite with 51–56 marginal plumose setae.
First maxilliped (Fig. 6 F). Coxal lobe with 5–8 setae; basal lobe with 14–17 setae; endopod unsegmented, often with terminal seta; exopod with strong lateral constriction, 5–8 marginal plumose setae. Second maxilliped (Fig. 6 G). Coxa and basis with several setae, respectively; endopod 4-segmented, each segment with several setae; exopod two-segmented, with 2–4 setae along inner margin of basal segment, distal segment with 7 terminal plumose setae.
Third maxilliped (Fig. 6 H). Coxa and basis with several setae, respectively; endopod 5-segmented, ultimate and penultimate segments heavily setose, remaining segments with scattered setae; exopod 3-segmented, penultimate segment with mesial seta.
Pereiopods (Fig. 7 A–E). Chelipeds similar; dactyl subequal to palm in length, each segment with scattered setae; ambulatory legs with dactyl terminating in corneous claw surrounded by setae, each segment with scattered setae; 4th pereiopod with scattered short setae on each segment; propodus with short and long setae plus marginal and submarginal corneous scales; dactyl terminating in corneous claw, with scattered short setae and single long seta; 5th pereiopod with scattered short setae on each segment; propodus and dactyl with several long, curved setae and corneous scales plus scattered short setae.
Pleon (Fig. 1 E). Six unarmed somites with scattered, laterally paired dorsal setae; biramous pleopods on pleomeres 2–5 (Fig. 6 J); exopod well developed, with 9 plumose setae; endopod simple lobe with 2 small coiled subterminal setae.
Tail fan (Fig. 6 I). Telson slightly wider than long, with scattered, laterally paired setae on dorsal surface; posterior margin with 9 long plumose setae and 2–3 short setae laterally; uropods biramous, symmetrical; exopod with 21 long plumose setae and 8–10 corneous scales marginally, plus 3–4 submarginal short setae; endopod margin with 13 long plumose setae, 4–7 short marginal setae and 3–6 corneous scales; protopod with 3 setae anterior to exopod base and 1 short seta between endopod and telson.
description: Published as part of Kato, Saori, Hamasaki, Katsuyuki, Dan, Shigeki & Kitada, Shuichi, 2015, Larval development of the land hermit crab Coenobita violascens Heller, 1862 (Decapoda, Anomura, Coenobitidae) described from laboratory-reared material, pp. 233-249 in Zootaxa 3915 (2) on pages 234-244, DOI: 10.11646/zootaxa.3915.2.3, http://zenodo.org/record/243341