Chloeia rosea Potts, 1909

Salazar-Vallejo, Sergio I., 2023, Revision of Chloeia Savigny in Lamarck, 1818 (Annelida, Amphinomidae), Zootaxa 5238 (1), pp. 1-134 : 106-108

Chloeia rosea Potts, 1909

Fig. 50

Chloeia rosea Potts, 1909: 357–358 , Pl. 45, Fig. 3 ; Fauvel 1932: 57; Fauvel 1953: 97–98, Fig. 46h (partim, RV Investigator, Sta. 242 is C. tumida Baird, 1868 ); Hartman 1959: 132.

Chloeia tumida?: Monro 1937: 253 (3 small juveniles from Maldives).

Type material. Indian Ocean, Amirante Islands. Holotype ( BMNH 1924.3.1.145), HMS Sealark, station not indicated, associated with a purple alcyonarian, 54 m, Oct. 1905, J.S. Gardiner, coll. (Note: Cooper (1909) recorded three species of Antipathes Pallas, 1766b for the Amiral Islands from the same expedition).

Diagnosis. Chloeia with pinnate branchiae from chaetiger 5, progressively smaller posteriorly; dorsum pink, without pigmentation pattern; anterior eyes slightly larger than posterior ones; caruncle with about 10 folds; notochaetae furcates and harpoon chaetae without spurs; neurochaetae furcates.

Description. Holotype (BMNH 1924.3.1.145), with body fusiform, 10.5 mm long, 3 mm wide, 20 chaetigers.

Holotype whitish, including chaetae ( Fig. 50A ); anterior prostomial margin blackish; dorsal cirri and branchiae pale. Venter brownish, midventral band paler, double; lips inner surface greenish.

Prostomium anteriorly entire. Eyes blackish, anterior eyes slightly larger than posterior ones. Median antenna inserted at anterior caruncular margin, as long as caruncle ( Fig. 50B ), 3× longer than lateral antennae. Lateral antennae bases separate from each other, slightly longer than palps. Mouth ventral on chaetiger 2. Pharynx not exposed.

Caruncle pale, sigmoid, trilobed, tapered, reaching chaetiger 4. Median ridge plicate, with about 12 vertical folds, partially concealing lateral lobes. Lateral lobes narrow, with about 16 vertical folds.

Pinnate branchiae from chaetiger 5, continued throughout body, convergent towards posterior region; progressively smaller posteriorly, longer than following segments in anterior ( Fig. 50C ) and median segments; in posterior segments as long as 1.5× successive segments. Median segments with 6–7 lateral branches (all without secondary branches, hence pinnate, not bipinnate).

Parapodia biramous, notopodia with cirriform branchiae along chaetigers 1–4, ¼–1/2 as long as dorsal cirri. Dorsal cirri slightly longer than bipinnate branchiae along median chaetigers, 2–3× longer in posterior chaetigers. Second ventral cirri with cirrophores slightly longer and wider, and cirrostyle slightly longer than adjacent ones, directed dorsally. Other ventral cirri directed ventrolaterally, as long as one subsequent segment.

Chaetae soft, most complete; distal fragile hoods and chaetal cortex variably eroded. Notochaetae in anterior chaetigers furcates ( Fig. 50D ), major tines 4—5× longer than minor ones. Median chaetigers with 2 types of notochaetae ( Fig. 50F ): furcates with smooth tines, major tines 3× longer than minor ones, and harpoon-chaetae with bifurcation region pigmented, denticulate tine 3—4× longer than smooth ones. Neurochaetae all furcates, anterior chaetigers with major tines 4× longer than minor ones ( Fig. 50E ); median chaetigers with furcates and furcate capillaries ( Fig. 50G ), major tines 3–5× longer than minor ones.

Posterior region tapered; pygidium with anus terminal; anal cirri lost (color, shape and size unknown).

Live pigmentation (from original description). Body reddish including chaetae. No other pigmentation features were given in the description.

Remarks. Chloeia rosea Potts, 1909 was described from the Indian Ocean; it is unique among Chloeia species by having pinnate branchiae, instead of being bipinnate like in the other species. There are three other species having branchiae from chaetiger 5, and without dorsal pigmentation pattern: C. longisetosa Potts, 1909 from the Indian Ocean, C. slapcinskyi sp. n., and C. wangi , the two latter ones from The Philippines. However, these three species have bipinnate branchiae, not pinnate, as in C. rosea .

The species was described with a small specimen (11 mm long, 20 segments) with reddish pink pigmentation, and it was found associated with a purple alcyonarian ( Potts 1909: 358). Regretfully, there were not enough details about the potential symbiont in the narrative for the expedition ( Gardiner & Cooper 1907a, b), nor in the account of the alcyonarians ( Cooper 1909). The relationship between these two species groups is quite interesting because most Chloeia species are regarded as free living, digging in sediments. From the original description, it was indicated that branchiae were convergent and long enough as to touch each other dorsally, and the illustration shows them with lateral branches tapered, clearly separated from each other, and this is confirmed in the holotype.

Distribution. Only known from the Admiral Islands, Indian Ocean, associated with alcyonarians, in substrates at 54 m depth.

Figures

FIGURE 3. Chloeia mezianei sp. n., non-type specimen (NHMD 915074). A. Left lateral view. B. Anterior end and pharynx, seen from above. C. Same, right lateral view. Scale bars: A, 1 mm; B, 0.6 mm, C, 0.5 mm.

FIGURE 46. Chloeia pulchella Baird, 1868, reinstated.A. Holotype of C. p. pallida Baird, 1868 (BMNH 1846.10.14.60), anterior end, dorsal view, after Methyl green staining. B. Chaetigers 17-20, dorsal view. C. Posterior region, dorsal view. D. Syntype of C. incerta de Quatrefages, 1866 (MNMH IA-TYPE 248), beheaded, anterior end, dorsal view. E. Chaetigers 16-19, dorsal view. F. Posterior region, dorsal view. Scale bars: A, E, 0.9 mm; B, 1.1 mm; C, 1.5 mm; D, 1.4 mm; F, 1.9 mm.

FIGURE 50. Chloeia rosea Potts, 1909, holotype (BMNH 1924.3.1.145).A. Dorsal view. B. Anterior end, dorsal view. C. Chaetigers 6-8, dorsal view. D. Chaetiger 3, notochaetae. E. Same, neurochaetal tips. F. Chaetiger 15, notochaetae (insets: chaetal tips). G. Same, neurochaetal tips. Scale bars: A, 1.2 mm; B, 0.5 mm; C, 0.4 mm; D, 110 μm; E, G, 50 μm; F, 120 μm.