Chloeia tumida Baird, 1868

Salazar-Vallejo, Sergio I., 2023, Revision of Chloeia Savigny in Lamarck, 1818 (Annelida, Amphinomidae), Zootaxa 5238 (1), pp. 1-134 : 110-112

Chloeia tumida Baird, 1868

Fig. 52

Chloeia incerta de Quatrefages, 1866: 388 ; Hartman 1959: 131; Solís-Weiss et al. 2004: S2; Salazar-Vallejo et al. 2014: 11 (list) (partim, syntype MNHN 246).

Chloeia tumida Baird, 1868: 232–233 , Pl. 4, Fig. 7a–d ; Fauvel 1917: 191; Hartman 1959: 132; Barroso & Paiva 2011: 422, Tab. 1.

Chloeia flava var. tumida: Monro 1931: 35 .

Chloeia rosea: Fauvel 1932: 57 ; Fauvel 1953: 97–98, Fig. 46h (non Potts, 1909; partim, RV Investigator, Sta. 242 only).

Chloeia tumida?: Monro 1937: 253 (3 specimens Maldives).

Type locality. India ( Baird 1868: 238).

Type material. Indian Ocean, India. Holotype ( BMNH 1972.68 ), Leach collection, Leadbeater, coll. (no further data). No locality (probably Indian Ocean ). Syntype of Chloeia incerta de Quatrefages, 1866 ( MNHN IA-TYPE 246 ), Freycinet, coll. (body colorless, chaetal features match C. tumida ; 140 mm long, 25 mm wide, 37 chaetigers ).

Additional material. Indian Ocean. One specimen ( BMNH 1937.9.2.12 – 13 ), John Murray Expedition , HEMS Mabahiss, Sta. 147 (04°53´12″ S, 72°54´30″ E), Horsburgh Atoll, anchorage, 27 m, 2 Apr. 1934 (juvenile; pale completely; bipinnate branchiae from chaetiger 4; most chaetae soft, smooth, acicular or furcates, a single harpoonchaeta in posterior chaetigers with accessory tine; body 6 mm long, 1.3 mm wide, 17 chaetigers). One specimen ( BMNH 1938.5.7.14 ), R .V. Investigator , Sta. 242 (17°27´N, 70°41´E), Arabian Sea, 101 m, 11 Oct. 1898 (date after Huys et al. 2014) (colorless, dorsal cirri purple; eyes minute; body bent ventrally, branchiae from chaetiger 4; neurochaetae with major tines 5–9× longer than minor ones; 26.5 mm long, 8 mm wide, 27 chaetigers). Red Sea. One specimen ( UF 6285 ), Saudi Arabia, Wasaliyat Island (17.7828, 41.4358; 17°46´58.08″ N, 41°26´08.88″ E), patch reef, 10 m, 17 Oct. 2014, D. Uyeno, R, Lasley, & J. Moore, coll. (juvenile; pale; ocular area pink, eyes blackish, anterior eyes 2× larger than posterior ones; median antenna 2/3 as long as caruncle; body appendages pale; body 11 mm long, 2.5 mm wide, 17 chaetigers) .

Diagnosis. Chloeia with bipinnate branchiae from chaetiger 4, progressively smaller posteriorly; dorsum pale, without pigmentation pattern; anterior eyes slightly larger than posterior ones; caruncle with about 40 folds; notochaetae acicular, tapered and harpoon chaetae without spurs; neurochaetae acicular, subdistally constricted (not spurred).

Description. Holotype (BMNH 1972.68) complete ( Fig. 52A ), pale; chaetae yellowish; venter pale; 148 mm long, 22 mm wide, 36 chaetigers.

Prostomium anteriorly entire. Eyes blackish, small; anterior eyes slightly larger than posterior ones. Median antenna inserted at anterior caruncular margin, 2/3 as long as caruncle, 2× longer than lateral antennae. Lateral antennae bases close to each other, 2× longer than palps. Mouth ventral on chaetiger 2–3. Pharynx not exposed.

Caruncle pale, sigmoid, trilobed, tapered, reaching chaetiger 4. Median ridge plicate, with about 38 vertical folds, almost completely concealing lateral lobes. Lateral lobes narrow, with about 33 vertical folds (difficult to count distally).

Bipinnate branchiae from chaetiger 4 ( Fig. 52B ), continued throughout body, mostly parallel along body; progressively larger to chaetiger 12–13, smaller in last 2–3 chaetigers. Median segments with 8–9 lateral branches per branchia.

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

Chaetae most complete, hoods most lost. Notochaetae in anterior chaetigers acicular, tip asymmetric ( Fig. 52D ), accessory tines not seen. Median chaetigers with one type of notochaetae ( Fig. 52F ): harpoon chaetae without spurs, subdistally swollen chaetae damaged, inner features modified. Neurochaetae all spurred, anterior neurochaetae with major tines about 20× longer than spurs ( Fig. 52E ), in median chaetigers aciculars and spurred chaetae, tines 20× (or more) longer than spurs ( Fig. 52G ).

Posterior end tapered; pygidium with anus terminal; anal cirri whitish, digitate ( Fig. 52H ), 5× longer than wide.

Live pigmentation. Unknown. Specimens collected by different people, using ethanol or formalin solution, were recorded as homogeneously pale; Monro (1937: 253) indicated in one of his three Maldives specimens, that median antenna was slightly purple, but the whole body was colorless.

Remarks. Chloeia tumida Baird, 1868 was described from India; it belongs in the group tumida because it has no dorsal pigmentation pattern, bipinnate branchiae from chaetiger 4, becoming progressively smaller posteriorly. Futher, because of its fusiform body, presence of acicular or spurred neurochaetae, and branchiae with lateral branches tapered, it resembles C. gilchristi McIntosh, 1924 , redescribed above from South Africa. However, these two species differ in the body color, complexity of the caruncle, and type of neurochaetae; in C. tumida the body is pale, its caruncular median ridge has about 38 vertical folds, and all neurochaetae are spurred, whereas in C. gilchristi the body is brownish, the caruncular median ridge has 11 vertical folds, and neurochaetae are spurred along anterior segments, and acicular in median segments.

The specific epithet (Latin tumidus, -a, -um: swollen) indicates either the swollen body, or that chaetae were subdistally swollen ( Baird 1868: 232), and both features were included in the diagnosis. Further, eyes were described as minute, no dorsal pigmentation in the holotype, and branchiae from chaetiger 4. Chaetae were indicated as denticulate. Fauvel (1917: 191) recorded the species for northern Australia after a 120 mm long specimen; he noted the specimen was milky white, without any trace of pigmentation, resembling the type specimen, and confirmed the subdistal swollen region in chaetae. Monro (1931) recorded specimens up to 110 mm long, milky-white to pale brown, and he indicated that “the absence of colour is a character of the animal in life and is not due to fading and the action of the preservative” ( Monro 1931: 35). A later report by Monro (1937:253) was made with hesitation after some specimens from the Maldives, but the doubt was after the small size of the specimens, the largest only 6 mm long.

As indicated above, the swollen subdistal section in harpoon chaetae is an artifact. However, the presence of tiny accessory tines in neurochaetae is quite distinctive, especially in larger specimens. On the other hand, the median antennae is slightly shorter than caruncle in MNHN IA-TYPE 246 and in juveniles (UF 6285).

Four damaged specimens from Singapore (three, BMNH 1931.10.8.3–4; one, BMNH 1961.11.1 –2) are pale, pinkish, or brownish, with a barely visible middorsal band along a few anterior chaetigers; bipinnate branchiae from chaetiger 4, many notochaetae broken, harpoon-chaetae and aciculars remain. Because of the lack of pigmentation pattern, they resemble C. tumida but neurochaetae differ by having longer minor tines, and each tine with a large distal hood, about as long as wide (in three specimens). If this feature could be used to separate this specimen from C. tumida cannot be solved now, and it must wait for the study of better-preserved specimens. Another specimen (BMNH 1888.12.5.3) from the Gulf of Manaar, also resembles C. tumida but its anterior notochaetae are furcates with long minor tines, instead of having them reduced to spurs; its neurochaetae do not have clearly defined hoods, and these two specimens are not conspecific, but also for this latter one, its formal description requires better preserved specimens.

Distribution. Red Sea to India and other Indian Ocean localities, in sediments at 10–101 m water depth.

Figures

FIGURE 7. Chloeia amoureuxi sp. n., holotype (MMSUCO Amp 2). A. Oblique dorsal view. B. Anterior end, left lateral view. C. Median segments, dorsal view. D. Chaetiger 3, notochaetal tips. E. Same, neurochaetal tips. F. Chaetiger 16, harpoon notochaetae. G. Same, neurochaetal tips. H. Posterior region, dorsal view. Scale bars: A, 0.7 mm; B, 0.05 mm; C, 1.5 mm; D, 160 μm; E, 110 μm; F, 180 μm; G, 30 μm; H, 2 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 52. Chloeia tumida Baird, 1868, holotype (BMNH 1972.68). A. Dorsal view, depressed by glass slide. B. Anterior end, dorsal view. C. Chaetigers 4-6, dorsal view. D. Chaetiger 3, notochaetal tips. E. Same, neurochaetal tips. F. Chaetiger 15, notochaetal tips, right one distorted by compression. G. Same, neurochaetae (inset: neurochaeta tip). H. Posterior end, dorsal view. Scale bars: A, C, 1.4 mm; B, 2.3 mm; D, 150 μm; E, 35 μm; F, 80 μm; G, 0.4 mm; H, 2.5 mm.