Halosydna brevisetosa Kinberg, 1856

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 : 1180-1181

Halosydna brevisetosa Kinberg, 1856

( Figure 1 )

Halosydna brevisetosa Kinberg, 1856: 385 ; Kinberg, 1858:18.

Halosydna johnsoni ( Darboux, 1899) : Darboux, 1899:246 (partim).

Halosydna brevisetosa: Hartman, 1949: 17–18 ; Salazar-Silva, 2006: 146–147.

Type material

Two syntypes ( SMNH 400) of Halosydna brevisetosa, Sausalito , San Francisco Bay, California, USA, Pacific North America, Eugenia Exped., 1851–53. One syntype ( LACM-AHF POLY 1583) of Polynoe reticulata , San Pedro, CA, USA, rocky shores near low water mark, probable commensal with “huge amphitrite”, 2 August 1895, coll. & id. as P. reticulata by H. P. Johnson. One syntype ( LACM-AHF POLY 1584) of P. reticulata , San Pedro, CA, USA, rocky shores near low water mark, probable commensal with “huge amphitrite”, 6 January 1896, coll. & id. as P. reticulata by H.P. Johnson.

Description

Two syntypes in poor condition, but complete; description based on best preserved specimen. Body with 36 segments, 2.2 cm long, 0.3 cm wide, pigmentation absent. Prostomium bilobed, as wide as long, without cephalic peaks; facial tubercle pointed; two pairs of eyes, anterior pair dorsolateral on widest part of prostomium, posterior pair dorsal, near posterior margin of prostomium; median antenna with ceratophore inserted frontally, 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 of similar shape to median antennae but shorter. Palps robust, tapering to filiform tips, surfaces with tiny papillae. Pharynx not everted.

Tentacular segment not visible dorsally; tentaculophores ventral to prostomium, with slender chaetae; tentacular cirri similar in shape to antennae.

Body with 18 pairs of elytra on segments 2, 4, 5, 7, 9, 11, then alternate to 21, 23, 25, 27, 28, 30, 31, 33. Three posteriormost segments cirrigerous; elytra fleshy, overlapping, covering dorsum ( Figure 1A ). First pair of elytra circular ( Figure 1B ); with marginal papillae ( Figure 1C ); surface covered with tiny digitiform papillae; macrotubercles conical, sclerotized, some thin, distally acute and slightly curved, others conical-thick and prominent over elytrophore scar ( Figure 1D,E ). Second and third pairs of elytra with similar ornamentation ( Figure 1A ) but sclerotized tubercles shorter, distally rounded. Elytra in posterior half of body oval ( Figure 1F ), with short marginal papillae; surfaces with granular appearance ( Figure 1F,G ) with numerous microtubercles and micropapillae; microtubercles conical - truncate, sclerotized, with tiny cusps or distally rounded.

Parapodia biramous, with small oocytes inside. Notopodia shorter than neuropodia. Neuropodia distally truncate, without projecting prechaetal lobe, with small rounded lobe near acicular tip. Dorsal cirri reaching neurochaetae tips, similar to antennae. Cirrophores cylindrical, basally expanded. Ventral cirri tapering to filifom tips. Nephridial papillae shorter on anterior segments. Anus dorsal, on segment 35. Pygidium wider than long, anal cirri absent.

Notochaetae shorter than neurochaetae with rows of spines; the smaller thick, curved, with blunt tips; remaining ones tapering to capillary tips. Neurochaetae with rows of spines on upper region, tips entire. First pair of parapodia with spinous neurochaetae, thiner than remaining, with tips entire.

Remarks

Halosydna brevisetosa can be distinguished by having all elytra margins fringed, with minute conical, truncate microtubercles, and conical macrotubercles on first pair of elytra; neurochaetae mainly unidentate, with only a tiny subdistal tooth in some midbody neuroparapodia.

The second syntype of SMNH 400 with a damaged prostomium, 3.7 cm long, 36 segments, 18 pairs of elytra. Pharynx everted, with nine pairs of papillae, two pairs of jaws with smooth margins. This specimen appears to correspond to Kinberg’s (1858) description .

The sytypes LACM-AHF POLY 1583 and LACM-AHF POLY 1584 of Halosydna johnsoni ( Darboux, 1899) agree with those of H. brevisetosa . However, the other syntypes clearly differ so that both species are herein considered as valid and H. johnsoni is redescribed below.

Members of this species have been extensively recorded from the tropical eastern Pacific, as well as worldwide. Here, the distribution is limited to California, USA. All other records are considered questionable. This species was synonymized with Halosydna nebulosa Marenzeller, 1902 , and so later recorded in Japon ( Imajima and Gamó 1970). The type materials of both species were examined and they are different species. Halosydna nebulosa is redescribed below.

Type locality

Sausalito, San Francisco California, USA.

Distribution

Known from California, USA: San Pedro, San Francisco.

Figures

Figure 1. Halosydna brevisetosa Kinberg, 1856. Syntype SMNH 400. (A) Anterior end, dorsal view; (B) first elytron; (C) same, fringe of papillae; (D, E) same, macrotubercles; (F) left elytron from middle segment; (G) same, fringe and microtubercles.