Aglaophamus agilis ( Langerhans, 1880 )

Ravara, Ascensão, Cunha, Marina R. & Pleijel, Fredrik, 2010, Nephtyidae (Annelida, Polychaeta) from southern Europe 2682, Zootaxa 2682 (1), pp. 1-68 : 7-11

Aglaophamus agilis ( Langerhans, 1880)

Figures 1 , 2

Nephthys agilis Langerhans, 1880: 304 , pl. XVI, fig. 39; Fauvel 1923: 372, fig. 145C–G.

Nephthys rubella Michaelsen, 1896: 19 , pl. I, figs. 5–8; Heinen 1911: 31, fig. 9, map 1; Fauvel 1914: 196; Fauvel 1923: 373, fig. 145H–I; not Berkeley and Berkeley 1945: 327.

Aglaophamus agilis Fauvel 1923: 372–373 , fig. 145c–g; Friedrich 1964: 135, fig. 1; Guille and Laubier 1966: 266; Hartmann-Schröder 1982: 9; Campoy 1982: 507; Laborda 2004: 412, fig. 151A.

? Nephthys squamosa Fauvel 1936: 41 .

Nephtys rubella Eliason 1962: 249 .

Nephthys (Aglaophamus) rubella Southward 1956: 264 ; Foret-Montardo 1969: 818, pl. IV, figs. 1–6.

Aglaophamus rubella Hartman 1950: 127 ; Fauchald 1963: 20, figs. 1E, 2A and 3H; Guille and Laubier 1966: 266; Wolff 1968: 6, fig. 12; Kirkegaard 1992: 327, fig. 159; Hartmann-Schröder 1974: 205 (partim); Hartmann-Schröder 1996: 216, fig. 93. Hartmann-Schröder 1971: 223, fig. 73C–D; Campoy 1982: 508.

Aglaophamus rubellus Dnestrovskaya and Jirkov 2001: 189 , fig.; Laborda 2004: 414, fig. 151C.

Type locality. Funchal , Madeira Island, Portugal .

Material examined. Atlantic Ocean. Norwegian waters: 1 incomplete spm ( ZMH V-3960, holotype of A. rubellus ). North Sea, Sweden, West Gullmarsfjorden, Bondens Hamn: RV Oskar von Sydow, 58º12.69’N, 11º19.00’E, 14–20 m, dredge, Apr 2003, 1 incomplete spm ( MB 36000137 as A. rubellus ). Scotland, off Shetland Islands: 2 incomplete spms ( NHM: 1865.3.9.18 as N. longisetosa ). Portugal, off Aveiro: cruise Aveiro 95, RV Côte d’Aquitaine, 40º48.434’N, 8º49.142’W, 34.9 m, grab, 1 Aug 1995, 3 incomplete spms ( DBUA 00062 as A. rubellus ); off Cascais: 38º39’– 38º42’N, 9º25’– 9º30’W, 40 m, Jun 1998, 1 incomplete spm ( DBUA 00871 as A. rubellus ) and 1 incomplete spm ( MB 36000132 as A. rubellus ); Madeira, Câmara de Lobos: 30 m, haul net, Jun 2000, 1 complete spm in poor condition ( MMF.36457); Porto Santo: subtidal, May 1991, 1 complete and 2 incomplete spms (in collection of J. Gil).

Mediterranean Sea. France, Banyuls: RV Nereis , 42º29.75’N, 3º8.40’E, 24 m, dredge, Jul 2004, 3 complete spms ( DBUA 01048) and 1 incomplete spm ( MB 36000142 as A. rubellus ).

Description. Examined specimens up to 24 mm long (for 45 chaetigers), and up to 59 chaetigers. See Fig. 2 for length and width measurements. Body slightly wider anteriorly, gradually tapering from middle region to pygidium. Poor dorsal delineation between anterior segments. Colour in ethanol salmon, with two longitudinal rows of purple spots near bases of parapodia; first two segments darker than following ones; prostomium with lightly pigmented area in middle of anterior region; two dark V-shaped lines near the posterior limit of prostomium; chaetae and aciculae amber. Eyes not visible. Pharynx distal region with 10 pairs of terminal bifid papillae, separated by simple dorsal and ventral papilla; middorsal and midventral papillae absent; subdistal region with 14 rows of up to 34 subterminal papillae, extending over 2/3 length of pharynx, proximal papillae close together and often 2–3 papillae arranged in triangular groups; proximal region smooth. Jaws conical. Prostomium subpentagonal, anterior margin slightly convex, posterior margin Vshaped extending over first chaetiger ( Fig. 1A ); antennae and palps long and conical with cirriform tip; palps slightly longer than antennae ( Fig. 2C ), inserted ventrolaterally on posterior region of prostomium. Nuchal organs rounded. Parapodia biramous; interramal space “U-shaped” anterioly, “V-shaped” medially and posteriorly, with small ciliated patches. Parapodia of chaetiger 1 shorter than subsequent ones, anteriorly directed, parallel to prostomium; notopodial acicular lobes conical, prechaetal lamellae poorly developed, rounded, postchaetal lamellae well developed but not extending beyond acicular lobes, rounded; neuropodium with pre- and postchaetal lamellae forming a cylinder covering acicular lobes; dorsal cirri very small, conical ( Fig. 2D ); ventral cirri cirriform with broad bases, similar in length to palps. Acicular lobes of following parapodia acutely pointed; prechaetal lamellae of both rami well developed but not extending beyond acicular lobes, bilobed with outer lobes shorter than inner; postchaetal lamellae extending beyond acicular lobes, conical in neuropodium, bilobed in notopodium, with dorsal lobes much larger than ventral, directed dorsally; dorsal cirri long, cirriform with broad bases; ventral cirri conical, lamelliform ( Fig. 1B–G ). Posterior parapodia acicular lobes acutely pointed; prechaetal lamellae of both rami poorly developed, slightly bilobed; postchaetal lamellae of both rami not extending beyond acicular lobes, rounded, directed dorsally on notopodium; dorsal cirri cirriform; ventral cirri conical, lamelliform. Branchiae involute, cirriform, lightly ciliated, present from chaetiger 2 to near posterior end of the body; occupy all interramal space when fully developed. Neuropodial superior lobe small and lamelliform, present from chaetiger 5. Chaetae long, of three kinds: barred chaetae in preacicular position ( Fig. 1H ), spinulated chaetae in postacicular position ( Fig. 1I ), and capillary chaetae in the neuropodia of chaetiger 1. One acicula with curved tips per ramus ( Fig. 1J ).

Remarks. The only specimen previously identified as A. agilis and examined in this study (MMF.36457), is in very poor condition and the observation of several important features was not possible. All the Langerhans’s material from Madeira is deposited in the Museum of Natural History of Wien, however no specimens of A. agilis , including the holotype, could be found there. No other material was available for examination. Aglaophamus agilis was originally described from Madeira Island by Langerhans (1880) who provided a very short and incomplete description. Friedrich (1964) recollected the species in the same locality and gave a more complete description together with a comparison with the other known species of Aglaophamus (including A. rubellus ). He considered the isolated occurrence of A. agilis in Madeira Island as an endemic condition. However, other authors, such as Fauvel (1923), Guille and Laubier (1966) and Desbruyères et al. (1972), reported the same species from the Mediterranean Sea, although without any further comments. According to Friedrich (1964), the species A. agilis and A. rubellus differ in the development of the prechaetal lamellae that are rudimentary in A. agilis and well developed and bilobed in A. rubellus , and in the shape of the notopodial postchaetal lamellae that are entire in A. agilis and bilobed in A. rubellus . However, Langerhans (1880) and Friedrich (1964) mentioned the presence of a pair of eyes in the anterior chaetigers of A. agilis , a feature typical of juvenile stages, which may also explain the rudimentary condition of the prechaetal lamellae. Since the prechaetal lamellae are smaller than the acicular lobes, they may be difficult to examine if not completely developed as it often happens in smaller juvenile specimens. As for the notopodial postchaetal lamellae, Friedrich (1964) also refers to the occasional presence of a small constriction at their lower edge. We think this constriction might be equivalent to the lower very small lobe of the bilobed lamellae in A. rubellus ( Fig. 1D–E ). Three Aglaophamus specimens collected in Porto Santo Island were examined and match the description of A. rubellus . Since all the differences between the two species may be explained by the juvenile condition of the A. agilis specimens examined by Friedrich we consider A. rubellus as a junior synonym of A. agilis . However, we have chosen not to designate a neotype for A. agilis . The synonymy with A. rubellus is based on a few formalin-preserved specimens from Madeira, and a designation in this case should preferably be associated to the deposition of material suitable for molecular analyses.

Aglaophamus agilis can be easily distinguished from the other southern European Aglaophamus species by the earlier beginning of branchiae (from chaetiger 2), the bilobed prechaetal lamellae and the higher number of pharynx subterminal papillae ( Table 3). From the measurements shown in Figure 2 , it is also evident the greater length of antennae, palps and first chaetiger ventral cirri of A. agilis in comparision to other species.

Distribution. Atlantic Ocean (from Norway to Mauritania); Mediterranean Sea (NE Spain; S France; Sicily, Corsega, Gulf of Génova) ( Fauchald 1963; Foret-Montardo 1969; Campoy 1982; Laborda 2004).

Habitat. Fine sand and mud, from the lower intertidal to 1100 m depth ( Foret-Montardo 1969; Laborda 2004). Specimens from the deeper locations were not available for examination and therefore these records should be considered with caution, as this species has been frequently confused with A. malmgreni .

Figures

FIGURE 1. Aglaophamus agilis. A. Pharynx and prostomium, dorsal view. B. Right parapodium of chaetiger 10, anterior view. C. Same, posterior view. D. Right parapodium of chaetiger 29, anterior view. E. Same, posterior view. F. Right parapodium of chaetiger 45, anterior view. G. Same, posterior view. H. Pre-acicular chaeta from chaetiger 29. I. Postacicular chaeta from chaetiger 29. J. Acicula from chaetiger 10.

FIGURE 2. Relationships between: A. Number of segments and body length. B. Body length and body width. C. Antennae and palps length. D. Length of ventral cirri (VC) and dorsal cirri (DC) of chaetiger 1. Aglaophamus elamellatus. - A. malmgreni. A. pulcher. A. rubellus. Minute dorsal cirri were scored as 0.01. A. elamellatus, A. malmgreni and A. pulcher plots include measurements from the original description (Théel, 1879; Eliason, 1951; Rainer, 1991).