Chloeia longisetosa Potts, 1909

Salazar-Vallejo, Sergio I., 2023, Revision of Chloeia Savigny in Lamarck, 1818 (Annelida, Amphinomidae), Zootaxa 5238 (1), pp. 1-134 : 79-81

Chloeia longisetosa Potts, 1909

Fig. 36

Chloeia longisetosa Potts, 1909: 357 , Pl. 45, Fig. 5 ; Hartman 1959: 131.

Type locality. Indian Ocean, South Suvadiva, Maldive Islands.

Type material. Indian Ocean, Maldive Islands. Holotype ( BMNH 1924.3.1.25), South Sudavida Atoll (0.50536°, 73.30147°; 00°30´19″ N, 73°18´05″ E), 81 m, mud, 1899, J.S. Gardiner, coll.

Diagnosis. Chloeia with bipinnate branchiae from chaetiger 5, branchiae as long as one successive segment, progressively smaller posteriorly; dorsum pale; median segments with chaetae markedly longer than body width; harpoon notochaetae with smooth tines; neurochaetae furcates.

Description. Holotype (BMNH 1924.3.1.25) complete, left parapodium of chaetiger 8 previously removed ( Fig. 36A ); body fusiform 11 mm long, 4 mm wide, 21 chaetigers.

Holotype pale; chaetae transparent, with irregular banding after coagulation of inner chaetal contents; dorsal cirri purple; branchiae pale. Venter pale, midventral band wide, pale.

Prostomium anteriorly entire ( Fig. 36B ). Eyes blackish, anterior eyes 2× larger than posterior ones. Median antenna inserted at anterior caruncular margin, 1/3 as long as caruncle, 2× longer than lateral antennae. Lateral antennae bases close to each other, slightly longer than palps. Mouth ventral on chaetiger 3. Pharynx not exposed.

Caruncle pale, sigmoid, trilobed, tapered, reaching chaetiger 6 ( Fig. 36C ). Median ridge plicate, with faint purple spots on top of each vertical fold, about 16 vertical folds, partially concealing lateral lobes. Lateral lobes narrow, with about 15 vertical folds.

Bipinnate branchiae from chaetiger 5 (chaetiger 4 with a smaller supernumerary branched branchia on the right side, and cirriform branchia), parallel throughout body, progressively larger to chaetiger 10–11, about as long as successive segment, progressively smaller thereafter. Branchiae in median segments with 7–8 lateral branches.

Parapodia biramous, notopodia with cirriform branchiae along chaetigers 1–4, ¼–1/5 as long as dorsal cirri. Dorsal cirri 5–6× longer than bipinnate branchiae along median chaetigers, dorsal cirri broken in posterior chaetigers, size relationships to branchiae unknown. Second ventral cirri slightly longer than adjacent ones, directed dorsally. Other ventral cirri directed ventrolaterally, as long as two subsequent segments, especially along posterior chaetigers.

Chaetae soft, with irregular inner bodies giving an irregular banding, most chaetae complete, distal hoods rarely eroded; noto- and neurochaetae of similar thickness. Notochaetae in anterior chaetigers furcates, major tines 3–4× longer than minor ones ( Fig. 36D ). Median chaetigers with two types of notochaetae: furcates with major tines 7× longer than minor ones, and harpoon-chaetae with denticulate tines 4× longer than smooth ones ( Fig. 36E ). Neurochaetae all furcates, major tines 3× longer than minor ones ( Fig. 36F ).

Posterior region tapered; pygidium with anus terminal; anal cirri pale, cylindrical, truncate, directed dorsally, 2–3× longer than wide ( Fig. 36G ).

Live pigmentation. Unknown. The description was less than 10 years after being collected. Body pale, purple spots in caruncle (still visible); dorsal cirri deep purple (still visible).

Remarks. Chloeia longisetosa Potts, 1909 was described from the Maldive Islands; because it has bipinnate branchiae from chaetiger 5, and lacks any dorsal pigmentation pattern, it belongs in the group longisetosa, together with C. slpacinskyi sp. n. described below, and C. wangi sp. n. also described below, both from The Philippine Islands. By having harpoon notochaetae it resembles C. slapcinskyi ; these two species differ especially after the relative size of median antenna to caruncle, chaetae, and branchiae. In C. longisetosa its median antenna is shorter than caruncle, the chaetae are markedly longer than body width, and its branchiae are short, as long as one successive segment, whereas in C. slapcinskyi median antenna is as long as, or longer than caruncle, the chaetae are as long as body width, and branchiae are long, as long as two successive segments.

Chloeia longisetosa was described having long and wide chaetae along posterior chaetigers, and the only feature illustrated was the posterior end. Because of its long chaetae, it has been regarded as an epitoke of C. fusca sensu Potts ( Fauvel 1953: 97, Hartman 1959: 131) because of their general similarity, and C. fusca was also recorded from the same archipelago. However, the median antenna is half as long as caruncle, eyes are small, and neurochaetae are thick, actually as thick as notochaetae, and not as thin furcate capillaries as would be expected during epitoky. Consequently, the species is herein regarded as distinct, and not an epitoke after its small eyes.

The record by Amoureux (1977: 1103), belongs elsewhere (see above under C. amoureuxi sp. n.).

Distribution. Maldive Islands, in mud, at 81 m water depth.

Figures

FIGURE 5. Chloeia bemisae sp. n., paratype, anterior fragment (UF 4388b). A) Chaetiger 3, right parapodium, posterior view, cirriform branchia cut (insets matched: 1, branchial cut tip; 2, branchial basal region; 3, dorsal cirrophore; 4, dorsal cirrostyle tip). B) Chaetiger 5, right parapodium, posterior view (insets matched: 1 and 2, branchial filament tip; 3, dorsal cirrostyle tip) (Br: branchia, DCs: dorsal cirrostyle). Scale bars: A, 0.20 mm; B: 0.38 mm.

FIGURE 36. Chloeia longisetosa Potts, 1909, holotype (BMNH 1924.3.1.25).A. Dorsal view. B. Anterior region, dorsal view, after Methyl green staining. C. Anterior end, dorsal view. D. Chaetiger 3, notochaetae (inset: notochaetal tip). E. Chaetiger 11, harpoon-notochaetae with smooth accessory tines. F. Same, neurochaetae. G. Posterior end, ventral view, after Methyl Green staining. Scale bars: A, 1.8 mm; B, 0.6 mm; C, 0.5 mm; D-F, 220 μm; G, 0.7 mm.