Chloeia pinnata Moore 1911
Creators: name: Yáñez-Rivera, Beatriz
name: Salazar-Vallejo, Sergio I.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Amphinomida
Amphinomidae
Chloeia
Chloeia pinnata

description: Chloeia pinnata Moore, 1911
Figs 1B, 2, 10
Chloeia pinnata Moore, 1911: 239–243, Pl. 15, Figs 1–6; Berkeley & Berkeley 1939: 323; Hartman 1940: 206–207, Pl. 31, Figs 10–13; Hartman 1963: 8; Loi 1980: 127; Kudenov 1995: 209–213, Figs 7.1, 7.2; Barroso & Paiva 2011: 422, Tab. 1; Yánez-Rivera 2015: 20–22, Fig. 2.5.
Chloeia rosea?: Fauvel 1943: 7 (non Potts, 1909).
Type material. California. Holotype [USNM 16842] Monterey Bay, R / V Albatross, Sta. 4475 (36°38’N, 121°55’W), 260 m, 16 May 1904. Paratypes [USNM-16901] same data as for the holotype (92).
Additional material. California. [LACM 992-39], off Santa Rosa Island, gravel and mud, 166–184 m, 10 Aug. 1939 (31, epitokes). [USNM 15827] Off Bodega Head, R / V Albatross, Sta. 3170 (38°17’N, 123°29’W), 305 m, 28 Mar. 1890, (30). [USNM 123116] W off Fort Bragg (39°27’ N, 123°57’ W), Sta. SB 30, “CARP”, 195 m, 24 Nov. 1987 (30, most juveniles).
Diagnosis. Chloeia with ventral cirri of chaetiger 2 2× longer than those of subsequent chaetigers; bipinnate branchiae from chaetiger 4; dorsum with a longitudinal pale band, surrounded by a darker red band; chaetal bundles homogeneously pale.
Description. Holotype (USNM 16842) complete, 24 mm long, 7 mm wide, 25 chaetigers; body fusiform, pale. Living specimens (Fig. 1B) with a middorsal pale band along a few anterior chaetigers, median and posterior chaetigers with a Y-shaped wide brownish band per segment, wider anteriorly, tapered posteriorly, progressively smaller posteriorly (Fig. 1B). Some preserved specimens reddish, dorsally with a longitudinal, pale line, and dorsal cirri deep violet. Some paratypes retain this pigmentation pattern (Fig. 10E).
Prostomium semicircular with four black eyes, anterior eyes 2–3× larger than posterior ones (Fig. 10C). Median antenna arising from anterior margin of caruncle (1.5 mm long), longer than lateral antennae (0.7 mm). Palps lateral, on buccal lips, similar in length to lateral antennae (0.6 mm). Mouth ventral on chaetiger 3.
Caruncle brownish, tapered into a conical tip (1.7 mm long, 0.5 mm wide). Median lobe with about 11 folds, a discontinuous band of subrectangular projections corresponding to folds (Fig. 10A, C) [this band is darker in live specimens]. Lateral basal lobes narrow, with 10 folds each. Branchiae from chaetiger 3, as single filaments or as small branchiae (Fig. 10B), better developed from chaetiger 4, continued throughout body; branchial bases colorless.
Parapodia biramous. Notopodium with cirriform branchiae along chaetigers 1–4, bipinnate branchiae from chaetiger 3 reduced, single or double or divergent filaments (as long as cirrophore). Second ventral cirri (2.2 mm long) about 2× longer than adjacent ones (1.0– 1.3 mm).
Neurochaetae include long and short furcates; in first chaetigers all shorter, wider (Fig. 10F) than those from posterior chaetigers (Fig. 10G, H); posterior chaetigers also bear long capillaries. Furcates with smaller tine very short, like a spur; relative length between neurochaetal tines 1:7–1:16. Notochaetae furcates; relative length proportions between tines 1:6–1:8. In first chaetigers some notochaetae with serrated inner borders (Fig. 10I); in medial and posterior chaetigers, serrated border barely distinct (Fig. 10J).
Posterior end tapered, anus terminal with two long, blunt pale anal cirri (Fig. 1B).
Variation. Epitokes collected in the same locality and date (LACM 992-39) were 11–23 mm long, 3.5–6.5 mm wide, 20–24 chaetigers. The body shape is not modified but the presence and abundance of capillary, natatory neurochaetae give a wider outlook for the posterior region. Dorsal surface pale, caruncle pale to brownish, dorsal cirri purple, branchial bases colorless. Anterior eyes 3× larger than posteriors in smallest specimen, becoming somewhat irregular in contour in larger specimens (18 mm long), but retaining the same proportion as in smallest specimens (Fig. 2). Largest specimens (23 mm long) with eyes distorted, irregular in shape, larger, approaching to each other laterally, with the same proportion. It is interesting that even the smallest specimen (11 mm long) has long capillary furcates in neuropodia, starting from chaetiger 6; each capillary chaetae 1/3 as wide as other furcates, with a tiny spur (shortest tine reduced). The caruncle is not hypertrophied, but the number of folds is size dependent (Fig. 2C, F, I), and it becomes slightly darker in larger specimens.
Remarks. Chloeia pinnata was described with branchiae starting in chaetiger 4 but Moore (1911) indicated that there was a third tiny cirrus dorsal to the dorsal cirrus and he thought they could be branchiae; however, no more details were provided. The first appearance of branchiae on chaetiger 3 allows differentiating C. pinnata from other species with first branchiae in chaetiger 4. In some paratypes, only one side of the worm shows the reduced branchial structure, and no scar was observed on the other side (Fig. 9D). This asymmetry has not been recorded in the literature.
Moore (1911) pointed out that the unworn state of notochaetae is slightly serrate; this species shows several kinds of chaetae, and the inner serrated border is evident mainly on anterior chaetigers. In the original description, information about pigmentation patterns is extensive but inacurrate. For example, Hartman (1940: 206) stated that this species lacks pigmented dorsal patterns and only minute dark specks are present. Reexamination of type material shows that C. pinnata has a rather solid dorsal pigmentation with a mid-dorsal pale line and dorsal cirri are violet.
The main differences between C. pinnata and the other three species in the Mexican Pacific are the dorsal pigmentation pattern and the branchial appearance (Table 1), as follows: 1) C. entypa from deep waters between Guerrero and Oaxaca, lacks pigmentation pattern and the first appearance of branchiae is on chaetiger 4; it also differs in the proportion of the length of second ventral cirri (3:1 while 2: 1 in C. pinnata), as well as chaetal features. 2) C. pseudeuglochis from shallow water in the Eastern tropical Pacific, has a different pigmentation pattern, which lacks a central pale line, and has regular-sized second ventral cirri. 3) Chloeia nuriae n. sp. from the Gulf of California differs in the pigmentation pattern showing only one central red line, while in C. pinnata the dorsum shows a continuous reddish pigmentation, except in the central pale line, and also differs in chaetal features, but both species share the large second ventral cirri (proportion 2:1).
Naville (1933: 173–174) noted that in epitoke Euphrosine foliosa Audouin & Milne-Edwards, 1833, the dorsal eyes were hypertrophied, and that there were abundant, very long interramal capillaries which he regarded as natatory chaetae; the caruncle or dorsal cirri were not modified. In C. pinnata, eyes are not hypertrophied, but neurochaetae include very long, thin capillaries with similar tips in addition to the typical furcates with tiny smaller tines. Further, smaller specimens had only spermatids, whereas larger specimens had oocytes, indicating that this species could be protandric. Despite their high abundance in shelf depths in California, about 200/m 2 (range: 16–1200/m2), being one of the most abundant marine annelid species (Jones & Thompson 1988), no swarming activity has been reported. We hypothesize reproduction may be happening in July to September since the specimens collected in August were mature.
Distribution. Southern California to Ecuador, in shallow water sediments, especially abundant in cooler waters.
description: Published as part of Yáñez-Rivera, Beatriz & Salazar-Vallejo, Sergio I., 2022, Revision of Chloeia Savigny in Lamarck, 1818 from tropical American seas (Annelida, Amphinomidae), pp. 503-537 in Zootaxa 5128 (4) on pages 521-523, DOI: 10.11646/zootaxa.5128.4.3, http://zenodo.org/record/6479987