Chloeia maculata Potts, 1909

Salazar-Vallejo, Sergio I., 2023, Revision of Chloeia Savigny in Lamarck, 1818 (Annelida, Amphinomidae), Zootaxa 5238 (1), pp. 1-134 : 81-84

Chloeia maculata Potts, 1909

Figs 37 , 38

Chloeia maculata Potts, 1910: 358 , Pl. 45, Fig. 4 , Pl. 46, Figs 1 , 2 , Horst 1912: 23 (footnote); Hartman 1959: 131.

Chloeia natalensis Day, 1951: 7–8 , Textfig. 1a, b; Fitzsimons et al. 1958: 2; Barroso & Paiva 2011: 422, Tab. 1.

Chloeia flava: Day 1967: 124 , Fig. 3.1.r (non (Pallas, 1766), but the figure matches the species).

Type material. Indian Ocean, Mauritius, Saint Brandon Rocks. Holotype of Chloeia maculata Potts, 1909 ( BMNH 1924.3.1.75), HMS Sealark, Sta. B15, 30 Aug. 1905, 54 m, J.S. Gardiner & M.A. Caius, coll. South Africa. Holotype of C. natalensis Day, 1951 ( BMNH 1961.16.6), Natal, Station 140, shore, J.H. Day, coll. (Durban Bay in Day 1951: 7).

Diagnosis. Chloeia with bipinnate branchiae from chaetiger 4, progressively smaller posteriorly; middorsal spots half-oval, displaced towards posterior segmental half; harpoon notochaetae with smooth tines, spurs, or without them; neurochaetae furcates.

Description. Holotype of C. maculata (BMNH 1924.3.1.75), complete, chaetae soft; body fusiform ( Fig. 37A ), 13 mm long, 4.3 mm wide, 22 chaetigers.

Holotype of C. maculata colorless; chaetae transparent; middorsal band purple from chaetiger 3 to end of body, becoming paler medially and posteriorly; each segment with spots longer than wide, half-oval in shape, barely visible along anterior segmental half, better defined in posterior half ( Fig. 37C ). Venter pale, midventral band single, pale.

Prostomium anteriorly entire. Eyes blackish, small, anterior eyes 2× larger than posterior ones (right posterior eye reduced). Median antenna inserted in anterior caruncular margin, almost as long as caruncle ( Fig. 37B ), almost 2× longer than lateral antennae. Lateral antennae bases separate from each other, 2× longer than palps. Mouth ventral on chaetiger 3. Pharynx not exposed.

Caruncle pale, bent, trilobed, tapered, reaching chaetiger 5. Median ridge plicate, with about 21 vertical folds, partially concealing lateral lobes. Lateral lobes narrow, with about 22 vertical folds.

Bipinnate branchiae from chaetiger 4, continued throughout body, parallel along body; progressively larger to chaetiger 12–13, smaller posteriorly along last few chaetigers. Branchiae in median segments with 7–8 lateral branches.

Parapodia biramous, notopodia with cirriform branchiae along chaetigers 1–4 (both types in chaetiger 4), half as long as dorsal cirri. Dorsal cirri 2× longer than bipinnate branchiae along median chaetigers, 3–4× longer in posterior chaetigers. Second ventral cirri with cirrophores 2× longer and wider, and cirrostyle 2× longer than adjacent ones, directed dorsally. Other ventral cirri directed ventrolaterally, as long as two subsequent segments.

Chaetae most complete. Complete chaetae with distal fragile hoods, rarely eroded. Notochaetae in anterior chaetigers furcates ( Fig. 37D ), major tines 3–4× longer than minor ones. Median chaetigers with two types of notochaetae: furcates with reduced minor tines, major tines 5× longer than minor ones, and harpoon-chaetae with a basal spur ( Fig. 37E ), denticulate tines 14–16× longer than smooth tines. Neurochaetae all furcates, major tines 3–4× longer than minor ones, more delicate in median chaetigers ( Fig. 37F ).

Posterior region tapered; pygidium with anus terminal; anal cirri pale, digitate, 5× longer than wide ( Fig. 37G ).

Live pigmentation. The holotype was described about three years after being collected. The original description indicated unpigmented body with an interrupted, dark purple middorsal band, better defined along posterior segmental half. Median and lateral antennae colorless; dorsal cirri and palps pink. Chaetae colorless. A recently collected specimen ( CAS 187535 ), has body pale, antennae and dorsal cirrostyles purple. Middorsal band blackish, half-oval shaped, displaced towards the posterior segment half, become wider in median chaetigers, thinner along anterior and posterior chaetigers; branchiae with pale stems and pinkish lateral branches; harpoon-chaetae with yellowish distal region. Anal cirri whitish .

Variation. The holotype of C. natalensis Day, 1951 ( BMNH 1961.16.6), was smashed in a shell vial smaller than its size, and segments are markedly contracted ( Fig. 38A ); its anterior and posterior ends are collapsed, the former is depressed, the latter is bent dorsally; most dorsal and ventral cirri lost. Body 42 mm long, 11 mm wide, 29 chaetigers .

The dorsal pigmentation is a longitudinal, interrupted purple band, better defined along the posterior half of each segment ( Fig. 38B ), and darker along a few anterior segments; anterior surface of notopodia with a purple hue. Branchiae pale. Chaetae brownish. Venter pale, midventral band pale.

Eyes blackish; anterior eyes slightly larger than posterior ones. Median antenna without tip, slightly shorter than caruncle, about 2× longer than lateral antennae. Caruncle twisted, reaching chaetiger 3 if gently pulled posteriorly. Branchiae from chaetiger 4, small, progressively larger to chaetiger 13–14, progressively decreasing posteriorly, as long as subsequent segment in median region, with 8–9 lateral branches.

Chaetae flexible, variably damaged by acidic formalin dissolution. Anterior notochaetae furcates, major tines 4× longer than minor ones. Median chaetigers with harpoon-chaetae without spurs, most without most denticles after dissolution ( Fig. 38C ). Neurochaetae furcates, major tines 4–5× longer than minor ones.

Posterior region tapered; pygidium with anus terminal, anal cirri pale, distorted dorsally after compression, digitate, 4× longer than wide ( Fig. 38D ).

Remarks. Chloeia maculata Potts, 1909 was described from the Western Indian Ocean; it belongs in the group flava because its bipinnate branchiae start in chaetiger 4, becoming progressively smaller posteriorly, and its dorsal pigmentation pattern has oval spots. There are also oval spots, longer than wide, in C. pulchella Baird, 1868 , reinstated (see below), described from Northeastern Australia. The main differences between these two species are in the shape of the dorsal spots, and in the type of notochaetae and neurochaetae. Thus, in C. maculata middorsal spots are half-oval, displaced towards posterior segmental half, its harpoon notochaetae have short smooth tines, and its neurochaetae have long minor tines, whereas C. pulchella has middorsal spots oval, central in each segment, its harpoon notochaetae lack spurs or smooth tines, and its neurochaetae are spurred or furcates with short minor tines.

Chloeia maculata Potts, 1909 was described with a small specimen (13 mm long, 20 segments); furcate neurochaetae were remarkable by being described as having the inner margin denticulate. Because of this type of chaetae, Horst (1910: 23, footnote) regarded its belonging into Chloeia as questionable. However, this type of chaetae cannot be confirmed in the holotype; the irregular margin might be due to chemical dissolution after formalin preservation, although a similar damage can be noted in older, ethanol preserved specimens. Nevertheless, the surface roughness is not regular, as can be seen when a row of denticles is present, or even after some dissolution removes their distal portions. On the other hand, the holotype of C. maculata is likely a juvenile, and although it might be regarded as a juvenile of other more pigmented Indian Ocean species, the pigmentation pattern is unique and should be regarded as a distinct species.

Day (1951: 7) described C. natalensis and diagnosed it as having branchiae from chaetiger 4, and ‘a median row of purple spots on dorsum, each amphora-like; dorsal bristles stout, serrated, but without spurs. Ventral bristles silky, with a spur but without serrations.’ He doubted about using the pigmentation pattern as a diagnostic feature, and this explains why he gave no further details about the shape and arrangement of the middorsal spots. The size proportions of cephalic appendages, as indicated by Day, are preserved in the specimen despite their current condition.

Day (1967: 120) indicated the synonymy of C. natalensis with C. flava (Pallas, 1766) , but that was incorrect, especially because the pigmentation patterns differ between these two species.

Chloeia maculata Baird, 1868 resembles C. amphora described from Indonesia (see above), because in the latter, its middorsal spots are less defined in smaller specimens. However, a comparison of similar-sized specimens indicates that in C maculata the band is restricted to the posterior segmental half, even in larger specimens, whereas in C. amphora , even small specimens have spots well defined, at least in those of comparable size to the holotype of C. maculata , and the feature is retained in larger specimens. In C. amphora the spot extends along the segment length, not being restricted to the posterior segmental half as is the case in C. maculata Potts, 1909 and C. natalensis Day, 1951 . The holotype of C. maculata is 18 mm long, whereas the type of C. amphora is 26 mm long, and it could be regarded that the middorsal spot progresses over the anterior segmental half in larger specimens, like in C. amphora . However, this is not consistent with what is shown in the type of C. natalensis , being 42 mm long, markedly larger than the types of the other species, but the dorsal spot is not extended anteriorly. Further, because the chaetal features are also similar, despite the fact of their surface dissolution, C. natalensis must be regarded as a junior synonym of C. maculata . They resemble both C. amphora , but the pigmentation pattern differs; the only difference between C. maculata and C. natalensis is that in the latter, the harpoon notochaetae lack any spur or accessory smooth tine; the difference can be relevant if confirmed in better preserved specimens, and likely useful for separating these two species, but additional specimens of the South African species are needed for clarifying if this difference is consistent throughout body.

Distribution. Mauritius to South Africa, in sediments from the intertidal to 54 m water depth.

Figures

FIGURE 1. Living specimens of four Philippine species of Chloeia Savigny in Lamarck, 1818. A. C. amphora Horst, 1910, dorsal view. B. C. bemisae sp. n., pink variant, dorsal view. C. Same, reddish and brownish variants, dorsal view. D. C. flava (Pallas, 1766), oblique right dorsal view. E. C. violacea Horst, 1910, oblique left dorsal view (scales not available; photos: Philippe Poppe; © Philippe & Guido Poppe – www.poppe-images.com).

FIGURE 2. Chloeia viridis Schmarda, 1861, non-type specimens (BMNH 1931.6.22.16-18). A. Black form, anterior region, dorsal view. B. Same, chaetigers 10-12, dorsal view (branchiae removed from chaetiger 11). C. Same, posterior region, dorsal view. D. Red form, anterior region, dorsal view. E. Same, chaetigers 12-14, dorsal view (branchiae removed from chaetiger 13). F. Same, posterior region, dorsal view. Scale bars: A, F, 0.9 mm; B, E, 0.7 mm; C, 1 mm; D, 1.2 mm.

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 4. Chloeia fusca M’Intosh, 1885, non-type specimen (UF 4368). A. Ventral view. B. Ventral view after body wall removed. C. Same, after Methyl Green staining. D. Same, lower half of digestive tube removed. (AI, anterior intestine; MB, midventral band (nerve chord); MR, muscular ridge; Oe, oesophagus; PI, posterior intestine; R, rectum; St, stomach). All scale bars: 1 mm.

FIGURE 37. Chloeia maculata Potts, 1909, holotype (BMNH 1924.3.1.75).A. Dorsal view. B. Anterior end, dorsal view, after Methyl green staining. C. Chaetigers 7-11, dorsal view. D. Chaetiger 3, notochaetal tips. E. Chaetiger 11, harpoon notochaetae. F. Same, neurochaetal tips. G. Posterior end, ventral view. Scale bars: A, 1.5 mm; B, 0.5 mm; C, 0.8 mm; D, 110 μm; E, 90 μm; F, 50 μm; G, 0.4 mm.

FIGURE 38. Chloeia maculata Potts, 1909, holotype of C. natalensis Day, 1951 (BMNH 1961.16.6). A. Oblique dorsal view. B. Chaetigers 13-18, dorsal view. C. Chaetiger 15, harpoon notochaetal tips. D. Posterior region, dorsal view. Scale bars: A, 0.5 mm; B, D, 1.3 mm; C, 90 μm.