Neanthes glandicincta Southern, 1921

Fazne Ibrahim, Nur, Shuaib Ibrahim, Yusof & Sato, Masanori, 2019, New record of an estuarine polychaete, Neanthesglandicincta (Annelida, Nereididae) on the eastern coast of Peninsular Malaysia, ZooKeys 831, pp. 81-94 : 85-86

Neanthes glandicincta Southern, 1921 Figs 3, 4

Nereis (Nereis) glandicincta Southern, 1921: 589-593, pl. 23, fig. 9 A–L, text fig. 5 a–c.

Nereis glandicincta : Fauvel 1932: 92-93; Fauvel 1953: 181-182, fig. 91 f–h.

Neanthes glandicincta : Lee and Glasby 2015: 80-85, figs 7-9.

Ceratonereis burmensis Monro, 1937: 532-536, fig. 1 a–f; Ng et al. 2011, in part.

Nereis (Ceratonereis) burmensis : Fauvel 1953: 196-197, fig. 97 d–f.

Ceratonereis (Composetia) burmensis : Hartmann-Schröder 1985: 49 (list); Chan 2009: 165-167, fig. 5 a–r, in part.

Type locality.

Brackish lakes or pools at four localities in Barantolla, Dhappa and Garia, near Calcutta in India (26 syntypes) ( Southern 1921).

Material examined.

Tumpat, Kelantan Delta, Kelantan, Malaysia: a specimen (BW, 1.3 mm; UMTAnn 428), around the jetty (6°12'03"N, 102°10'29"E), coll. M. Sato, 13 August 2009; 5 (BW, 1.6-2.0 mm; NSMT 113250), around the river mouth of Sungai Mak Neralang (6°12'46"N, 102°10'34"E), coll. M Sato, 13 August 2009; 2 (BW, 1.5-2.0 mm; UMTAnn 429), natural mangrove forest (6°12'50"N, 102°10'43"E), coll. M Sato, 13 August 2009. Setiu Lagoon, Terengganu, Malaysia: 3 (BW, 1.6-1.8 mm; UMTAnn 430), site 102, northwest of Terrapuri Heritage Village, Penarik (05°38'12.5"N, 102°46'52"E), coll. M Sato et al., 10 August 2009; 8 (BW, 1.5 mm -2.0 mm; NSMT 113251), site 103, northwest of site 102 (05°38'38.4"N, 102°46'20.2"E), coll. M Sato et al., 10 August 2009; 2 (BW, 1.2-1.7 mm; UMTAnn 431), Muara Kuala Setiu (05°40'26.3"N, 102°43'17.4"E), coll. YS Ibrahim et al., 6 August 2015; Kuala Ibai, Terengganu, Malaysia: 2 (BW, 0.7 mm -1.1 mm; UMTAnn 432), around the river mouth of Sungai Ibai (5°17'04"N, 103°10'23"E), coll. M Sato et al., 12 August 2009.

Diagnosis.

Based on Southern (1921), Lee and Glasby (2015), and the present study. Maxillary ring of proboscis with conical paragnaths (0-17, usually approx. 10, scattered and unequal in group I; 10-23, large and curved in group II; 30-63, in 4 rows of transversely elongated bands in group III; 10-22, large in group IV). Oral ring of proboscis with only few minute rudimentary paragnaths, often with none (0 in group V; 0 or 1, seated on tip of round papilla in group VI; up to approx. 8 in a single row in Group VII-Group VIII). Total paragnaths more than 70.

Description.

Largest complete specimen 70 mm BL, 2.0 mm BW, with 132 chaetigers. Colour in preserved specimens is whitish cream with brownish pigmentation on prostomium, anterior part of palps, and dorsum of anterior chaetigers. Sub-pentagonal prostomium with a pair of smooth tapered antennae situated at anterior end (Figs 3, 4A). A pair of palps with massive palpophores and short conical palpostyles. Two pairs of eyes arranged trapezoidally (anterior pair with space wider than that of posterior pair); anterior pair reniform and slightly larger; posterior pair round and smaller. Mid-longitudinal white slit present on dorsal anterior surface of prostomium. Peristomium with four pairs of tentacular cirri of unequal length; posterodorsal tentacular cirri longest, reaching back to chaetigers 6-12 (Figs 3, 4A).

Proboscis with a pair of light brown jaws, each with approx. ten teeth. Typical conical paragnaths present on maxillary ring (Figs 3, 4A); number of paragnaths on each group are as follows (Table 1): group I: 3-13, scattered and unequal; group II: 13-20 in two arched rows, marked large paragnaths with sharply tapering and curved tip present in middle position; group III: 39-58, in three or four rows of transversely elongated bands; group IV: 11-17 in a triangular patch with markedly large paragnaths present in posterior position. Oral ring sometimes expanded into a trapezoidal shape at full-everted proboscis, with only a few or no rudimentary paragnaths; number of paragnaths on each group are as follows (Table 1): group V: none; group VI: 0 or 1 minute paragnath seated on tip of small round papilla, sometimes only papilla present; groups VII–VIII: 0 or 1 minute paragnath present. Total number of paragnaths 94-137.

Parapodia of first two chaetigers uniramous, all following parapodia biramous. Uniramous parapodia of first two chaetigers are without notoacicula. In subsequent biramous parapodia, notopodia consists of dorsal cirrus, dorsal ligule, prechaetal lobe and ventral ligule throughout (Fig. 4 B–D); all ligules/lobes are conical with tapering tip throughout; ventral ligule subequal to or slightly smaller than dorsal ligule; prechaetal lobe much shorter than two ligules. Dorsal cirri tapering, shorter than notopodial dorsal ligule throughout (about half length). Glandular patches present along dorsal edge of dorsal and ventral ligules.

Neuropodia consisting of superior lobe, inferior (acicular) lobe, postchaetal lobe, ventral ligule and ventral cirrus present in anterior and middle body, but lack superior lobe in posterior body (Fig. 4C, D); postchaetal lobe present throughout; all ligules/lobes are conical with tapering tip throughout. Ventral cirrus is slender with tapering tip. Glandular patches present along ventral edge of neuropodial ligule/lobes.

Notochaetae all homogomph spinigers having long blades with finely serrated edges (Fig. 4E). Upper neurochaetae include homogomph spinigers with long blades (posteriorly) and heterogomph spinigers with short blades (anteriorly, Fig. 4F) throughout; some or most of heterogomph spinigers are replaced by heterogomph falcigers with slender blades (Fig. 4G) in middle body. Lower neurochaetae include heterogomph spinigers with long blades (posteriorly) and heterogomph spinigers with short blades (anteriorly) throughout; some or most of heterogomph spinigers with short blades are replaced by heterogomph falcigers in middle body. Heterogomph falcigers first appear around chaetiger 20 in both upper and lower neurochaetae.

Reproduction.

The coelom of a female specimen collected from Tumpat, Kelantan Delta on 13 August 2009 (BW 1.7 mm) was filled with oocytes (probably immature eggs) 100-140 µm in diameter.

Habitat.

Intertidal sandy or muddy flats in estuaries. Salinity in habitats highly varied; the salinity of surface water at Muara Kuala Setiu in Setiu Lagoon varied in a range from 22.4 to 28.3 psu ( Nicholas 2018), while the salinity of interstitial water at the other sites, Setiu Lagoon, Kuala Ibai, and Tumpat, was in the range from 3.0 (Site 103 in Setiu Lagoon) to 16.5 psu (Tumpat).

Geographical distribution.

India, Myanmar, western Singapore, the eastern coast of Peninsular Malaysia. Based on synonymy with C. burmensis , and Southern (1921), Lee and Glasby (2015) and the present study.