Neanthes pleijeli, León-González & Salazar-Vallejo, 2003

León-González, Jesús Angel De & Salazar-Vallejo, Sergio I., 2003, Four new nereidid species (Annelida, Polychaeta) collected during the MUSORSTOM cruises in the Indo-Pacific Ocean, Zoosystema 25 (3), pp. 365-375 : 371-373

Neanthes pleijeli n. sp.

( Fig. 3 )

TYPE MATERIAL.— New Caledonia. LAGON, stn 737, 22°08.4’S, 166°59.1’E, 49-50 m, 12.VIII.1986, holotype (MNHN-POLY 72).

ETYMOLOGY.— This species is named in honor Fredrik Pleijel (MNHN) because of his important publications on taxonomy of Polychaeta in general and his support to this research.

OTHER MATERIAL EXAMINED.— Philippines. MUSORSTOM 3, stn 111, 14°00.1’N, 120°19.4’E, 178-190 m, 2.VI.1985, 1 specimen (ECOSUR).

Wallis et Futuna. MUSORSTOM 7, stn 498, 14°00’S, 177°00’W, 108-140 m, 10.V.1992, 1 specimen (UANL 5080).

DISTRIBUTION.— Western Pacific Ocean.

DESCRIPTION

Holotype incomplete posteriorly, with 40 setigers, 35 mm long, 7 mm wide including parapodia. Prostomium pentagonal in shape with two pairs of eyes in trapezoidal arrangement, a pair of short frontal antennae. Biarticulate palps with spherical palpostyle. Peristomium as long as first setiger, with four pairs of tentacular cirri, the longest reaching setiger 6 ( Fig. 2A ).

Pharynx with brown jaws, each with five teeth; paragnaths as: I = 2 cones in line; II, III, IV, V, VI without cones; VII-VIII = 6 cones in line.

Parapodia of first two setigers uniramous, thereafter biramous. Anterior notopodia with dorsal and median ligule distally conical, median ligule with a swollen base, superior lobe rounded, similar in length to the other two notopodial ligules.

Neuropodium with postsetal lobe expanded, rounded distally, presetal lobe longer than postsetal one, conical distally. Dorsal and ventral cirri subequal ( Fig. 3B ). Mid-posterior parapodia with dorsal and median ligule elongate, superior lobe reduced. Neuropodium with postsetal lobe mamilliform, ventral ligule subulate. Dorsal cirri longer than ventral one ( Fig. 3C ).

Notosetae homogomph spinigers troughout the body, with long thin blades. Anterior supracicular neurosetae homogomph spinigers and heterogomph falcigers, last one with short blade; infracicular setae heterogomph spinigers in superior position, heterogomph falcigers with longer blade in middle position ( Fig. 3D ), and heterogomph spinigers in inferior position. Mid-posterior parapodia with supracicular neurosetae homogomph spinigers and two simple hooks with an apical tooth directed downwards of ( Fig.3E ); infracicular setae heterogomph and homogomph spinigers in superior position, heterogomph falcigers with short blade marginally toothed, with an apical tooth directed downwards in middle position ( Fig. 3F ), and in inferior position heterogomph falcigers with long blade, similar to those of anterior parapodia.

Pygidium unknown.

REMARKS

The presence of a simple supracicular neuroseta is a rare feature in Neanthes . In fact, this has been a traditional feature to separate Hediste Malmgren, 1867 from Nereis Linnaeus, 1758 and some species in Platynereis Kinberg, 1866 . However, these simple setae show a completely or almost completely fused blade with the handle making nonsensical any comparison of this new species with anyone in those genera. It remains to be evaluated if that feature should be regarded as a primitive or derived feature, but that is beyond the scope of this paper. It must be added, however, that the presence of a simple seta has been employed by Hartmann-Schröder (1985) to define her subgenus Simplisetia in Ceratonereis Kinberg, 1866 , and that she also transferred Neanthes anchylochaeta Horst, 1924 to her new subgenus. Within that perspective, Neanthes pleijeli n. sp. might belong there too. Nonetheless, these two species differ from any other species in that grouping by having paragnaths over the pharynx oral ring, Anterior parapodia with subequal dorsal and rendering its placement in those taxa inadequate median triangular ligules, superior lobe missing, since they belong to Neanthes . neuropodia formed by a subconical postsetal Neanthes pleijeli n. sp. is closely related to lobe, ventral ligule globose. Dorsal cirri inserted N. anchylochaeta but they differ principally in medially, longer than ventral one ( Fig. 4B ). pharyngeal arrangement: N. anchylochaeta pre- Median parapodia with dorsal ligule shorter than sent in area I = 3 cones in line; II = 8-9 cones in median one, superior lobe missing, postsetal lobe line; IV = 8 cones in line; VI = 0-1 cone; VII-VIII expanded basally, ventral ligule triangular. Dorsal

= 3 cones in one line spread. In N. pleijeli n. sp. and ventral cirri subequal ( Fig. 4C ). Posterior area I = 2 cones in line while areas II, III, IV, V, parapodia with short dorsal ligule ( Fig. 4D ).

VI lack cones and VII-VIII = 6 cones in line. Notosetae homogomph spinigers troughout the Fauvel (1953) recorded N. anchylochaeta from body. Supracicular neurosetae of anterior parapo- India, but his specimens were different from dia are one homogomph spiniger with long thin Horst’s (1924) specimens because of the presence blade, one sesquigomph falciger with longer of three cones in line in pharynx area III. blade similar to that of spinigers, but with a short apical tooth directed down, a sesquigomph falciger with normal blade; infracicular ones, three

Genus Nicon Kinberg, 1866 sesquigomph falcigers similar to last one, with the inner margin of the blade dentated, and a short

Figures

FIG. 3. — Neanthes pleijeli n. sp.; A, anterior region, dorsal view; B, setiger 10, anterior view; C, setiger 35, anterior view; D, neuropodial infracicular heterogomph falciger from anterior parapodium; E, neuropodial supracicular simple seta from mid-posterior parapodia; F, neuropodial infracicular heterogomph falciger from same. Scale bars: A, 1 mm; B, C, 300 µm; D, F, 15 µm; E, 30 µm.

FIG. 2. — Neanthes philippinensis n. sp.; A, anterior region, dorsal view; B, setiger 10, anterior view; C, setiger 46, anterior view; D, setiger 65, anterior view; E, neuropodial supracicular heterogomph falciger from anterior parapodia; F, infracicular heterogomph falciger from same; G, neuropodial supracicular heterogomph falciger from mid-anterior parapodia; H, neuropodial infracicular heterogomph falciger from same; I, neuropodial supracicular heterogomph falciger from middle parapodia; J, neuropodial infracicular heterogomph falciger from the same. Scale bars: A, 1 mm; B-D, 250 µm; E-J, 30 µm.

FIG. 4. — Nicon pettiboneae n. sp.; A, anterior region, dorsal view; B, setiger 10, anterior view; C, setiger 29, anterior view; D, setiger 45, anterior view; E, neuropodial infracicular sesquigomph falciger from anterior parapodium; F, heterogomph falciger from same; G, neuropodial supracicular heterogomph falciger from posterior parapodia; H, neuropodial infracicular sesquigomph falciger from same. Scale bars: A, 0.1 mm; B-D, 100 µm; E-G, 15 µm; H, 30 µm.