Terebellidae Johnston 1846
- Dataset
- The “ Spaghetti Project ”: the final identification guide to European Terebellidae (sensu lato) (Annelida, Terebelliformia)
- Rank
- FAMILY
Classification
- kingdom
- Animalia
- phylum
- Annelida
- class
- Polychaeta
- order
- Terebellida
- family
- Terebellidae
description
Figs 1 C – D, 5 – 6
description
Main morphological characters of European species BRANCHIAE. The number and shape of branchiae are very important to separate species of Terebellidae s. s. Typically, species 2 – 3 pairs of branchiae are present on SG II – III or II – IV, but members of some genera, as for Polycirridae, completely lack branchiae: Baffinia, Lanassa, Laphania, Leaena, Phisidia and Proclea. Terebella banksyi is characterised by having branchiae on discontinuous segments: SG II – III and V (Fig. 5 D). Generally branchiae are branching (dichotomous or arborescent), originating dorsolaterally from a main stalk (Figs 5 A – D, 6 A – D) or a single point on body wall, but some species have multiple unbranching branchial filaments, like Amphitrite cirrata or A. rzhavskyi. The presence or absence and the size of the branchial stem is important, like in Eupolymnia (Figs 5 A – B, 6 D). LOBES. Genera of Terebellidae s. s. are distinguished from each other by the presence (or absence) and morphology of anterior lobes, usually positioned laterally. These structures are flaps of tissues covering at least part of the preceding segment (Nogueira et al. 2010) (Figs 5 B – C, 6 A – D). They can be absent, as in Nicolea or Terebella, narrow, as in Paramphitrite birulai or large, as in Lanice and Eupolymnia (Fig. 5 A – C) and they also vary significantly in morphology and position, from ventral to dorso-lateral (Figs 5 B – C, 6 A – D). NEPHRIDIAL AND GENITAL PAPILLAE. Terebellids are characterised by the presence of papillae situated close to the notopodia or between parapodial lobes. The nephridial papillae occur from SG III – V, while genital papillae are present from SG VI onwards and are prominent only when the animals are mature (Fig. 5 C – D, 6 C). When they are visible, the morphology and the number of these papillae and their number permit the discrimination of species, as for Amphitrite or Terebella for example. NOTOPODIA AND NEUROPODIA. Terebellidae s. s. differ by the number of pairs of notopodia, the segment on which notopodia and neuropodia start and the morphology of both noto- and neurochaetae. Usually, notochaetae are present on 17 segments, beginning from SG IV, but several exceptions exist as for example for Lanassa (n <15) or Terebella (n> 25, often present to the pygidium). Notochaetae of Terebellidae are divided in two types: distally smooth as in Pista, Eupolymnia or Lanice, or distally serrated as in Amphitritides or Paramphitrite (Fig. 5 E), and each types are sub-divided in sub groups (Nogueira et al. 2010: table 4). Concerning the neurochaetae, each part of the uncinus (Fig. 1 C – D) differ greatly among the genera of Terebellidae and their morphology should be examined in detail. For example, members of the genus Pista have long-handled uncini, with the handle originating from the heel (Fig. 1 C), while uncini in most of the other genera have short-handles. Contrary to tendons which are soft and thin structures attached to uncini, handles are chitinous structures extended from the heel. Members of the genus Loimia are unique due to the presence of pectinate uncini, with teeth arranged vertically in a single row (Fig. 1 D), while other species have multiple transverse rows of secondary teeth above the main fang (Fig. 6 E – G). The dorsal button is generally well developed and situated about midway between the base of the main fang and the tip of the prow, but is inconspicuous in specimens of Lanice and can be closer to the tip of the prow, as in Eupolymnia gili or the base of the main fang, as for Artacama proboscidea. Finally, the prow and the heel vary in shape and can be distally rounded or pointed.
diagnosis
Diagnosis (after Hutchings et al. 2021 a, most important diagnostic characters highlighted in bold) Transverse prostomium attached to dorsal surface of upper lip; basal part as thick crest, eyespots frequently present (Fig. 5 B), in short rows at each lateral sides, or extending transversely across basal part of prostomium. Buccal tentacles all usually uniformly cylindrical. Peristomium usually forming lips only; lips expanded, relatively short upper lip, hood-like, about as long as wide; swollen, usually button-like and mid-ventral lower lip. Segment I terminating laterally to ventro-laterally, partially fused to expanded lower lip, or developed, forming lobes of variable extension and position. Lobes on anterior segments frequently present, of variable length, sometimes extending to SGV – VII (Figs 5 B – D, 6 A – D). Anterior segments highly glandular ventrally, with discrete, smooth to corrugated, rectangular to trapezoidal mid-ventral shields extending from anterior segments until termination of notopodia, or near it; mid-ventral groove extending from termination of mid-ventral shields. Two to three pairs of branchiae usually present (Figs 5 A – D, 6 A – D), but three genera have a single pair and several are abranchiate; branchial filaments originating all together from single point on body wall, on either side of branchiferous segments, unbranched, or, more frequently, originating from conspicuous main stalk on either side of pair, branching from one to several levels, in plumose (spiraled), dichotomous, pectinate or arborescent arrangement. Notopodia beginning on SGII – V, SGIV in most genera, usually extending to mid-body, around SGXX, but sometimes present on fewer segments or extending more posteriorly for variable extension, rarely until near posterior end; first pairs of notopodia inserted dorso-laterally, progressively more laterally, then vertically aligned; cylindrical to rectangular notopodia. Notochaetae originating from central core on top, distal lobes absent; notochaetae distally winged, wings of variable length and width, or serrate, sometimes with wings at midlength, basally to a serrated blade; some more specialised types of notochaetae may be present (Fig. 5 E – G). Neuropodia beginning posteriorly to notopodia, on SGV – IX, usually on SGV; neuropodia in conjunction with notopodia as low, sessile ridges, sometimes continuing posteriorly until pygidium, but most taxa with rectangular to cylindrical or foliaceous neuropodial pinnules after notopodia terminate; neurochaetae as avicular uncini usually as long as high, with short triangular heel directed posteriorly, slightly curved and wide base, and dorsal button (Figs 1 C – D, 6 E – F); uncini arranged in double rows (Fig. 6 E) from around SGXI usually until termination of notopodia, but several genera with double rows.
discussion
Remarks In European waters, the Terebellidae s. s. are represented by 19 genera and 44 species (Table 1). Four genera are represented only by a single species: Artacama Malmgren, 1866; Baffinia Wesenberg-Lund, 1950; Laphania Malmgren, 1866; Leaena Malmgren, 1866 and Stschapovella Levenstein, 1957. Eleven of them are represented by two European species each: Amphitritides Augener, 1922; Axionice Malmgren, 1866; Lanassa Malmgren, 1866; Lanice Malmgren, 1866; Loimia Malmgren, 1866; Nicolea Malmgren, 1866; Paramphitrite Holthe, 1976; Phisidia Saint-Joseph, 1894; Pistella Hartmann-Schröder, 1996; Proclea Saint-Joseph, 1894 and Terebella Linnaeus, 1767 (Lavesque et al. 2021). The genus Eupolymnia Verrill, 1900 is represented by four species and the two most diverse European genera are Amphitrite Müller, 1771, with ten species, and Pista Malmgren, 1866 with eleven (Lavesque et al. 2021). In our recent paper focusing on French Terebellidae s. s. we have confirmed the synonymy of Neoamphitrite with Amphitrite, as suggested by several authors (Jirkov 2020; Hutchings et al. 2021 a). In contrast, we consider that Amphitritides, Lanice Loimia and Paramphitrite are still valid genera (Read & Fauchald 2021), contrary to what was proposed by Jirkov (2020) (see details in Lavesque et al. 2021).