Namanereis christopheri, Conde-Vela, Victor Manuel, 2017

Conde-Vela, Victor Manuel, 2017, The troglomorphic adaptations of Namanereidinae (Annelida, Nereididae) revisited, including a redescription of Namanereiscavernicola (Solis-Weiss & Espinasa, 1991), and a new Caribbean species of Namanereis Chamberlin, 1919, Subterranean Biology 23, pp. 19-46 : 23-26

Namanereis christopheri sp. n. Fig. 2

Namanereis cavernicola Glasby, 1999: 83-86, figs 8c, 35 a–g (partim, non Solís-Weiss and Espinasa 1991).

Type locality.

Saint Vincent, Lesser Antilles.

Etymology.

The specific name is after Christopher J. Glasby, in recognition of his numerous contributions in polychaete taxonomy, especially about nereidid taxonomy, and because he identified this species as new after his first evaluation (see below).

Type material.

Holotype LACM-AHF 1227 and paratypes LACM-AHF 1228 (1), and LACM-AHF 1229 (10), Golden Grove, near Chateaubelair Bay (13 º 17'18"N, 61 º 14'25"W), Saint Vincent, Saint Vincent and the Grenadines, 31 July 1972, 435 m above sea level, spring pool in Colocasia ( Araceae ) swamp, Coll. J.J. Rankin.

Description.

Holotype complete, 32 mm long, 1 mm wide at chaetiger 10, 95 chaetigers; body with several parapodia removed in middle region, otherwise in good condition. Paratypes complete, in good conditions, 10-30 mm long, 1-2 mm wide, 62-95 chaetigers. Body pale, without pigmentation (Fig. 2A, B).

Prostomium wider than long, anterior margin entire, groove present; antennae cirriform, as long as prostomium; eyes absent (Fig. 2A, C). Tentacular ring as long as first chaetiger; three pairs of tentacular cirri, longest one reach chaetiger 3 (Fig. 2A, C); cirrophores 1.5-2.0 times longer than wide. Pharynx dissected; jaws with layer running throughout cutting edge, two distal teeth, with bifid appearance (Fig. 2E). Pharynx with cushion-shaped papillae on area VI (Fig. 2D), papillae rounded, laterally fused; other areas smooth.

Parapodial cirri pattern: Dorsal cirri longer than neuropodial lobes, basally inserted throughout body. Ventral cirri shorter than neuropodial lobes, basally inserted throughout body.

In anterior chaetigers (Fig. 2F), dorsal cirri 3 times longer than neuropodial lobes; neuropodial lobes rounded, as long as wide, as long as ventral cirri; ventral cirri half as long as dorsal ones. In middle chaetigers (Fig. 2 G–H), dorsal cirri twice longer than neuropodial lobes; neuropodial lobes rounded, slightly longer than wide, twice longer than ventral cirri; ventral cirri one-third to one-half as long as dorsal ones. In posterior chaetigers (Fig. 2I), dorsal cirri twice longer than neuropodial lobes; neuropodial lobes rounded, as long as wide, 3 times longer than ventral cirri; ventral cirri half as long as dorsal ones.

Notochaetae absent. Neurochaetae in type D arrangement, i.e. supra-acicular chaetae heterogomph falcigers and sesquigomph spinigers in pre- and post-acicular fascicles respectively; sub-acicular chaetae heterogomph falcigers with short and long blades in pre-acicular fascicles.

Supra-acicular sesquigomph spiniger pectinated, teeth minute, decreasing slightly in size towards tip (Fig. 2J, N); supra-acicular heterogomph falcigers pectinated, teeth minute, decreasing slightly in length towards tip (Fig. 2L). Sub-acicular falcigers pectinated, teeth minute, tip falcate, decreasing slightly in size towards tip; upper heterogomph falcigers long bladed, blades 2-3 times longer than lower ones (Fig. 2K, O), lower falcigers stouter than upper ones (Fig. 2 L–M).

Pygidium tripartite; anal cirri cirriform, short, as long as last chaetiger (Fig. 2B).

Remarks.

The material of this species was previously examined by Glasby (1999) and identified as N. cavernicola . The three vials from the Los Angeles Museum include two labels. One label has the name "Lycastopsis F", identified in 1988, and includes the designation of holotypes and paratypes. The other label has another unpublished manuscript name, dated 1990. Likely, Glasby initially regarded it as a new species, but later he changed his mind and included them with N. cavernicola ( Glasby 1999) resulting in an amphiamerican distribution. The incised anterior margin of prostomium and other features were compared with Lycastoides alticola but not with N. cavernicola , arguing that the only difference among Caribbean and Pacific materials were the longer dorsal cirri in N. cavernicola ( Glasby 1999: 85). The result was a description of. N. cavernicola with mixed features and encompassing high ranges of variation.

On the other hand, N. christopheri sp. n. and N. cavernicola share some features as having falcigers with relative long blades and blades with several minute teeth. However, they have some important differences. First, N. christopheri sp. n. has an anterior margin of prostomium entire and antennae are shorter than prostomium, while in N. cavernicola the anterior margin is incised and antennae are longer than prostomium. Further, tentacular cirri in N. christopheri sp. n. are smooth and reach chaetiger 3, while in N. cavernicola they are annulated and reach chaetiger 5-6. In addition, N. christopheri sp. has jaws much broader than N. cavernicola . N. cavernicola has neuropodial lobes tapered, subconical with pointed tips, two or three times longer than wide, while in N. christopheri sp. n. they are rounded and as long as wide; and parapodial cirri in N. cavernicola are thinner than in N. christopheri sp. n.

As indicated in the key below, N. christopheri sp. n. is also closely related to N. hummelincki , differing mainly in chaetal features as Glasby (1999: 85) previously noted. In N. christopheri the blades of sub-acicular falcigers and spinigers have several, minute teeth and they have a similar size along the cutting edge, while in N. hummelincki they have fewer teeth, and the basal ones are notably longer than medial and distal ones.

Glasby (1999: 85) noted, after the revision of parapodia of N. cavernicola , several grades of curvature in notoaciculae and even in neuroaciculae, which are absent in N. christopheri sp. n., and considered them as artifacts of preservation. However, since all notoaciculae observed had recurved tips, this feature is regarded here as specific one. Glasby (1999: 74) thought that these features, together with the presence of articulated antennae and tentacular cirri were not sufficient to recognize Lycastilla as distinct, and this decision is herein corroborated. Finally, all specimens of N. christopheri sp. n. were whole-mounted and examined under microscope, no spinigers were found in sub-acicular fascicles; the long-bladed, uppermost sub-acicular chaetae in Fig. 2 H–I have falcate tips, i.e., they are falcigers. The species does not replace upper long-bladed falcigers by spinigers toward posterior chaetigers, sharing this peculiarity with N. gesae .