Dodecaceria laddi Hartman, 1954

Magalhães, Wagner F. & Bailey-Brock, Julie H., 2013, Bitentaculate Cirratulidae (Annelida: Polychaeta) from the northwestern Pacific Islands with description of nine new species, Zootaxa 3630 (1), pp. 80-116 : 111-112

Dodecaceria laddi Hartman, 1954

Figure 22 A–D

Dodecaceria laddi Hartman, 1954: 638 , figs. 176c, 177d–h.

Dodecaceria laddi: Woodwick 1964 . Day 1967: 502, fig. 20.1.g–i. Reish 1968: 223. Gibbs 1971: 180. Bailey-Brock et al. 1980. Bailey-Brock 1987: 372–374, fig. 3.II. 152. Devaney & Bailey-Brock 1987: 101.

Material examined. South of Anaehoomalu Bay, northwestern shore of Big Island, Hawaii, 19° 51 42.77 N, 155° 55 47.94 W, coll. R. Brock (2). Mamala Bay, Waianae outfall, southeast shore of Oahu Island, Hawaii, Sta. W2R1, 30 m, Jul. 1990 (1); Hanauma Bay, south shore of Oahu Island, Hawaii, Keyhole Sta., 0 8 Jul. 1999, coll. R. Brock (5, USNM 1195176; 5, BPBM R3655; 27); Johnston Atoll, Sta. 3, 25 May 1976, collected in hard substrate, 7 m (1); Johnston Atoll, Sta. 1, transect 5, 23 Apr. 1976, coll. R. Brock (1). Enewetak Atoll, Marshall Islands, lagoon, Oct. 1975, coll. R. Brock (1 on stub, USNM 1195177; 1); Guam, Mariana Island, Sta. 0 5, Jan. 2006 (5).

Description. Specimens 2.5–7.0 mm long, 0.4–0.8 mm wide for about 17–47 chaetigers. Body cylindrical in cross section; posterior segments flattened dorso-ventrally. Pygidium conical with anal opening placed terminally ( Fig. 22 B). Body color in preserved specimens varied from dark brown on prostomium, peristomium, and chaetigers 1 and 2 and pale brown throughout or whitish to transparent throughout, probably due to time in ethanol.

Prostomium blunt, without eyes and nuchal organs not observed ( Fig. 22 A). Peristomium longer than prostomium, as long as three anterior chaetigers, without subdivisions ( Fig. 22 A). Dorsal tentacles shorter than branchiae, inserted laterally at junction between peristomium and chaetiger 1 ( Fig. 22 A). Two pairs of branchiae, first pair arising between the peristomium and first chaetiger, second pair arising between chaetigers 1 and 2 ( Fig. 22 A).

Anterior parapodia with only 3–4 capillary chaetae with serrated edge; noto- and neurohooks up to three (rarely four) per fascicle, present from chaetiger 8 and accompanied by one capillary chaeta until posterior end ( Fig. 22 C); notopodial spoon-shaped hooks thicker than neuropodial hooks ( Fig. 22 D).

MGSP. No staining reaction.

Remarks. The specimens described by Day (1967) as D. laddi have palps longer than the branchial filaments. However, in the specimens herein described, the palps are shorter or the same-size as the branchiae, in agreement with the original description by Hartman (1954). We believe that relative length of branchiae and tentacles are not a relevant character since they are both usually lost or regenerating.

Dodecaceria laddi is unique in the genus in having only 2 pairs of branchiae. Other species with few branchiae are Dodecaceria diceria Hartman, 1951 from Florida (1 pair) and D. gallardoi Carrasco, 1977 from Chile (3 pairs).

Biology/Ecology. Several specimens were found with anterior or posterior end regenerating. This species has been collected boring coral rubbles or shell fragments.

Distribution. Dodecaceria laddi is widespread in western Pacific Islands and has been found in the Hawaiian Islands of Big Island, Maui and Oahu (Bailey-Brock 1987), Marshall Islands (Hartman 1954; Reish 1968; Bailey- Brock et al. 1980), Solomon Islands (Gibbs 1971) and newly recorded from Johnston Atoll.

Figures

FIGURE 22. SEM of Dodecaceria laddi. A, anterior end, dorsal view; B, posterior end with pygidium; C, abdominal chaetiger showing noto- and neurohooks, notohooks thicker and with deeper cavity than neurohooks; D, notopodial spoon-shaped hook.