Halosydna nebulosa ( Grube, 1876 )

Salazar-Silva, Patricia, 2013, Revision of Halosydna Kinberg, 1856 (Annelida: Polychaeta: Polynoidae) from the Tropical Eastern Pacific and Grand Caribbean with descriptions of new species, Journal of Natural History 47 (17 - 18), pp. 1177-1242 : 1207-1210

Halosydna nebulosa ( Grube, 1876)

( Figures 14 , 15 )

Polynoe (Halosydna) nebulosa Grube, 1876: 49 .

Halosydna nebulosa: Marenzeller, 1902: 567–569 , plate 1, figure 1; Hartman, 1938: 109.

Type material

One syntype ( ZMB 1170 ) of Chefoo , China, Leg. Reimann, id. Grube .

Description

Syntype complete, with 36 segments. Prostomium bilobed, wider than long, without cephalic peaks; facial tubercle present, without pigmentation; two pairs of eyes; median antenna with ceratophore inserted at same level as prostomium, style subdistally expanded, tapering to filiform tip, lateral antennae with ceratophores inserted terminally as prolongations of prostomium lobes, at same level as ceratophore of median antenna, styles similar to median antenna. Palps robust taper to filiform tips, surfaces with small papillae. Pharynx not everted.

Tentacular segment not visible dorsally; tentaculophores with slender chaetae, acicula tip emergent. Segment 2 with two small dorsal tubercles.

Body with 18 pairs of elytra inserted on segments 2, 4, 5, 7, 9, 11, then alternate to 21, 23, 25, 27, 28, 30, 31, 33. Three posteriormost segments with dorsal cirri. First pair of elytra rounded ( Figure 14A ) with short papillae on margins ( Figure 14B,D ), surfaces with microtubercles, papillae and macrotubercles. Microtubercles conicalslender, sclerotized, abundant, scattered over entire surface. Macrotubercles conicalslender, sclerotized, abundant ( Figure 14C–F ). Second pair of elytra with thick papillae on margins; surfaces with microtubercles and macrotubercles conical, sclerotized, amber, the microtubercles on anterior half, macrotubercles on posterior half. Elytra in median and posterior segments oval ( Figure 14G,H ), with papillae on margins and surfaces with microtubercles short, conical, distally blunt, scarce.

Notopodia shorter than neuropodia. Neuropodia distally truncate with protruding acicular tip, prechaetal lobe with small rounded lobe near acicula tip. Dorsal cirri similar to antennae. Cirrophores basally expanded. Elytrophores wider than dorsal tubercles. Nephridial papillae elongated in median and posterior segments. Ventral cirri taper to filiform tips ( Figure 15A ). Pygidium with two anal cirri similar to dorsal cirri.

Notochaetae with rows of spines, the smaller curved, with blunt tips ( Figure 15B ); the larger slender, taper to capillary tips ( Figure 15C ). Neurochaetae with rows of spines on upper region ( Figure 15F ), tips entire, lightly curved ( Figure 15D–E ).

Remarks

Halosydna nebulosa was redescribed by Marenzeller (1879, 1902). The syntype herein examined is from Chefoo (now Yantai city), China, This species has not been recorded in the Grand Caribbean or the tropical eastern Pacific, but is included to clarify their identity because this species is not considered valid and has been listed as a synonym of H. brevisetosa for Imajima and Gamó (1970). However, the latter has prominent macrotubercles on the anterior elytra, principally over the elytrophore mark, and microtubercles mainly around the margin, while the former has abundant macrotubercles and microtubercles scattered over all the elytral surface. Therefore, both species are herein redescribed separately, and the respective distributions are clarified.

Type locality

Chefoo (now Yantai city), China.

Distribution

Same as type locality.

Figures

Figure 14. Halosydna nebulosa (Grube, 1876). Syntype ZMB 1170. (A, B) First elytron; (C) same, macrotubercles; (D) same, fringe; (E, F) same, macrotubercles; (G) left elytron from posterior segment; (H) same, microtubercles.

Figure 15. Halosydna nebulosa (Grube, 1876). Syntype ZMB 1170. (A) Neurochaetae; (B) lower notochaetae; (C) upper notochaetae; (D–F) unidentate neurochaetae.