Neanthes philippinensis, 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 : 368-370

Neanthes philippinensis n. sp. ( Fig. 2 )

TYPE MATERIAL.— Philippines. MUSORSTOM 3,

stn 142, 11°47’N, 123°02’E, 25 m, 6.VI.1985, holoin type (MNHN-POLY 76), 5 paratypes (MNHN- POLY 77), 3 paratypes (UANL 5079), 3 paratypes (ECOSUR), 2 paratypes (NMP).

ETYMOLOGY.— The specific name refers to the Philippine Islands, where it was found.

DISTRIBUTION.— Known only from the type locality, Philippine Islands.

DESCRIPTION

The holotype is a complete specimen, 26 mm long, 4 mm wide including parapodia, with 74 setigers. Prostomium longer than wide, two pairs of eyes in trapezoidal arrangement, distal ones smaller than proximal ones; a pair of cirriform frontal antennae. A pair of biarticulate palps, with conical palpostyles. Peristomium longer than next two segments, with four pairs of short tentacular cirri, longest reaching setiger 4 ( Fig. 2A ).

Pharynx with brown jaws, each with six teeth; paragnaths as: I = 3 cones in line; II = 9 cones in line; III = 5 cones in group; IV = 9 cones in line; V = 0; VI = 3 cones in line; VII-VIII = 5 cones in line.

Parapodia of first two setigers uniramous, thereafter biramous. Anterior parapodia with short dorsal and median ligules, last one swollen basally, superior lobe rounded distally; neuropodium with a postsetal lobe rounded anteriorly, ventral ligule conical. Dorsal cirri thin, smaller than ventral ones ( Fig. 2B ). Median parapodia with subequal notopodial dorsal and median ligules, superior lobe not seen; neuropodium with conical postsetal lobe, presetal lobe thin, ventral ligule short, slightly subulated. Dorsal cirri longer than ventral one ( Fig. 2C ). Posterior parapodia with dorsal ligule longer than median one; postsetal lobe mammilliform distally, triangular ventral ligule ( Fig. 2D ).

Notosetae homogomph spinigers throughout the body, with long thin blade, 23 in anterior, 17 in middle-anterior, seven in median and five in posterior setigers. Anterior neuropodia have in supracicular position 11 homogomph spinigers and three heterogomph falcigers ( Fig. 2E ); infracicular setae are six heterogomph spinigers with short thin blade, two heterogomph spinigers with short wide blade, nine heterogomph falcigers with dentition along inner margin of the blade, a short apical tooth directed downwards ( Fig. 2F ), and three heterogomph spinigers with short wide blade. Mid-anterior neurosetae in supracicular position eight homogomph spinigers and three thick heterogomph falcigers with six short basal teeth in the inner margin ( Fig. 2G ); infracicular ones, four heterogomph spinigers and nine heterogomph falcigers ( Fig. 2H ). Neurosetae of middle parapodia in supracicular position, four homogomph spinigers and two heterogomph falcigers ( Fig. 2I ), infracicular ones three heterogomph spinigers and three heterogomph falcigers ( Fig. 2J ). Posterior neuropodia each with two heterogomph spinigers and two heterogomph falcigers; infracicular ones a heterogomph spiniger and three heterogomph falcigers.

Pygidium terminal with a pair of long and thin anal cirri.

REMARKS

Neanthes species are currently grouped following Fauchald (1972) and Wilson (1984) proposals which rely on the parapodial lobes development, notably the notopodial ligule, and on the presence or absence of falcigers. Neanthes philippinensis n. sp. belongs to group II B 1, because it has falcigers, smooth parapodia and its notopodial ligule is slightly longer than other parapodial ligules or lobes. This group contains 43 species which could be subdivided by paragnath patterns in pharynx areas VII-VIII and by the number of notopodial structures; thus, N. philippinensis n. sp. like N. agulhana (Day, 1963) , N. kerguelensis (McIntosh, 1887) and N. nanhaiensis Wu, Sun & Yang, 1985 , have a single row of paragnaths in area VII-VIII, and anterior notopodia are provided with dorsal and middle ligules as well as a superior lobe. The more closely related species to N. philippinensis n. sp. is N. kerguelensis ; however, they differ in several features: dorsal cirri in N. kerguelensis have not the basal swollen characteristic of N. philippinensis , blade of falcigers distally blunt without accessory sharply bent distal tooth, and area VI of pharynx with only one paragnath, although in some occasions this does not appear ( Wilson 1984). We examined two syntypes and 17 specimens of N. kerguelensis deposited in The Natural History Museum (London), and observed the presence of one small paragnath on each area VI; furthermore, area I in these specimens has only one paragnath, and only one of the syntypes (1885.12.1.170) shown the paragnaths in line on area I, while in N. philippinensis n. sp. three paragnaths in line are present.

N. bongcoi (Pillai, 1965) , another species described from the Philippine Archipelago, differs from N. philippinensis n. sp. by having neuropodial falcigers provided with long, distally rounded blade, and two paragnath rows with six paragnaths each in pharynx area VII-VIII; as has been stated above, in N. philippinensis n. sp. the pharynx area VII-VIII has a single row with four or five paragnaths. The paratype of N. bongcoi deposited in The Natural History Museum (London) differs hardly of type species described by Pillai, all pharynx arrangements are different (I = 5 cones in group; II = 21 paragnaths in triangle; III = 23 in oval group; IV = 29 in crescent group; V = 0; VI = one big cone in each side, and a small cone in the inner basal part of area VI; VII-VIII = 52 in two rows). For this reason we think that this paratype corresponds to a species different from N. bongcoi , which has not been described yet. Other species provided with few paragnaths in area VII-VIII are N. dawydovi (Fauvel, 1939) , N. galetae Fauchald, 1977 , N. maculata Wu, Sun & Yang, 1985 , and N. unifasciata (Willey, 1905) . However, all these species have notopodia with only dorsal and middle ligule throughout the body. The three analyzed specimens show variation in the pharyngeal arrangement: Area I = 1-3 cones; II = 8-11 cones in line; III = 3-5 cones in group; IV = 6-9 cones in line; VI = 2-3 cones; VII-VIII = 4-5 in line. Jaws with four to six teeth.

Figures

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.