Chloeia fucata de Quatrefages, 1866

Salazar-Vallejo, Sergio I., 2023, Revision of Chloeia Savigny in Lamarck, 1818 (Annelida, Amphinomidae), Zootaxa 5238 (1), pp. 1-134 : 50-51

Chloeia fucata de Quatrefages, 1866 reinstated

Fig. 21

Chloeia fucata de Quatrefages, 1866: 390 ; Baird 1868: 232; Hartman 1959: 131; Solís-Weiss et al. 2004: S2.

Type material. Indian Ocean, Arabian Sea. Holotype ( MNHN IA-TYPE 80, Mascate (Muscat), Oman, M. Leclancher, coll., no further data.

Diagnosis. Chloeia with tiny bipinnate branchiae from chaetiger 3, gradually larger medially, progressively smaller posteriorly; middorsal spots subrectangular, longer than wide, sometimes wider medially; notochaetae furcates and harpoon-chaetae without spurs; neurochaetae furcates.

Description.

Holotype ( MNHN IA-TYPE 80) complete, with slight histolysis; body subrectangular, 43 mm long, 10 mm wide, 27 chaetigers.

Holotype pale, chaetae golden ( Fig. 21A ); prostomium, cephalic appendages, dorsal and ventral cirri pale, from chaetiger 14 a middorsal dark spot oval, longer than wide ( Fig. 21D ), better defined along last 5–6 chaetigers. Spots displaced towards posterior segmental margin, barely wider medially. Venter pale.

Prostomium anteriorly entire. Eyes blackish, small, anterior eyes slightly larger than posterior ones ( Fig. 21B ). Median antenna inserted at anterior caruncular margin, contracted, about half as long as caruncle, 2× longer than lateral antennae. Lateral antennae bases very close to each other, about 2× longer than palps. Mouth ventral on chaetiger 2. Pharynx slightly exposed, smooth, with moderate histolysis, muscular wall very thin.

Caruncle bent to the right, trilobed, tapered, reaching posterior margin of chaetiger 3 ( Fig. 21C ). Median ridge plicate, with about 23 vertical folds, almost completely concealing lateral lobes at least along half its length. Lateral lobes narrow, with about 20 vertical folds, posterior ones indistinct, fused to median ridge tip.

Bipinnate branchiae from chaetiger 3, continued throughout body. First pair of bipinnate branchiae small ( Fig. 21C , asterisks); cirriform branchiae present in the same segment. Bipinnate branchiae directed posteriorly, more or less convergent along posterior chaetigers; branchiae progressively larger to chaetiger 10, and then slightly larger posteriorly, becoming longer than segmental length. Bipinnate branchiae with up to 7–8 lateral branches in median segments.

Parapodia biramous, notopodia with cirriform branchiae along chaetigers 1–3, about as long as dorsal cirri in chaetiger 1, becoming half as long in chaetiger 3. Dorsal cirri slightly longer than bipinnate branchiae along median chaetigers, becoming up to 2× longer in posterior chaetigers. Second ventral cirri with cirrophores and cirrostyles slightly longer than those present in adjacent chaetigers, directed dorsally. Other ventral cirri directed ventrolaterally, as long as one segment.

Chaetae variably broken, distally covered by a mass of epizoic filamentous orgnisms. Complete chaetae with distal fragile hoods, usually eroded. Notochaetae in anterior chaetigers furcate, major tines 5–6× longer than minor ones ( Fig. 21E ). Median chaetigers with 2 types of notochaetae: furcates with reduced minor tines, major ones 5–6× longer than shortest ones, and thicker harpoon-chaetae ( Fig. 21F ). Neurochaetae all furcates, in median chaetigers major tines 3–4× longer than minor ones ( Fig. 21G ).

Posterior end tapered ( Fig. 21H ); pygidium with anus terminal; anal cirri pale, subcylindrical, blunt, 7–8× longer than wide.

Live pigmentation. Unknown; dorsal cirri originally described as turned into intense red.

Remarks. The specific epithet (Latin fucatus, a, um means to stain in red; French fardée, made-up) was given because “the only specimen had all body appendages with their purple pigmentation turned into intense red” ( de Quatrefages 1866: 390). In the Latin diagnosis, he indicated branchiae were medium-sized, and that the type was 4o mm long, 9 mm wide, with 27 segments.

Chloeia fucata de Quatrefages, 1866 is unique by having bipinnate branchiae from chaetiger 3, and by the presence of a discontinuous middorsal longitudinal band, slightly displaced towards the segmental posterior half, resembling middorsal oval spots. This pigmentation pattern is also present in C. pulchella Baird, 1868 , reinstated, originally described from northeastern Australia, and its branchiae are rather short (after Horst 1912 and Fauvel 1953 illustrations), not as long as one complete segment length, as in C. fucata , although this might result of the contraction of the body, more muscular than branchial stems. Thus, heavily contracted specimens might have apparently longer branchiae, in comparison to segment length, than those specimens less contracted.

Fauvel (1923: 134), and later Hartman (1959: 131) regarded C. fucata as a junior synonym of C. venusta de Quatrefages, 1866 , described from the Mediterranean Sea, probably after the confusion by M’Intosh (1876: 395). However, M’Intosh hesitated about the species name and added a question mark after the name; his records include specimens collected in sediments from 81–230 m water depth in the Mediterranean Sea. The pigmentation pattern M’Intosh reported was a continuous brown middorsal band, and a similar band along the anterior part of each segment, thus rather approaching C. venusta instead. This might hardly be regarded as conspecific with the Omani species, as the comparison of the specimens has shown, and hence they are herein regarded as distinct species.

Although uncommon, cirriform branchiae might be present in the first segment where bipinnate branchiae start ( Yáñez-Rivera & Salazar-Vallejo 2022). The holotype of C. fucata has bipinnate branchiae from chaetiger 3, together with cirriform branchiae. Solving the enigma about this early start whether this is an ontogenetic variant in a species having bipinnate branchiae from chaetiger 4, must wait for additional specimens. An ongoing project in Oman has not found specimens of Chloeia so far (G. Paulay, 2022, pers. comm.). If additional specimens show the holotype of C. fucata differs from typical specimens by having supernumerary bipinnate branchiae in chaetiger 3, then C. fucata would have priority over C. pulchella .

Distribution. Only known after the original description, from Muscat, Oman.

Figures

FIGURE 21. Chloeia fucata de Quatrefages, 1866, holotype (MNHN IA-TYPE 80). A. Right lateral view, after Methyl green staining (MGS). B. Anterior end, oblique right lateral view, after MGS. C. Anterior region, dorsal view (asterisks indicate first non-cirriform branchiae). D. Median chaetigers, dorsal view. E. Chaetiger 3, notochaetae; F. Chaetiger 13, notochaetal tips; G. Same, neurochaetal tips. G. Posterior end, dorsal view. Scale bars: A, 5 mm; B, C 0.7 mm; D, 1.1 mm; E, F, 100 μm; G, 40 μm; H, 1.7 mm.