Synelmis glasbyi, Salazar-Vallejo, 2003

Salazar-Vallejo, Sergio I., 2003, Revision of Synelmis Chamberlin, 1919 (Annelida, Polychaeta, Pilargidae), Zoosystema 25 (1), pp. 17-42 : 28-30

Synelmis glasbyi n. sp. ( Fig. 6 )

TYPE MATERIAL. — Syntypes: southwestern Indian Ocean, Mozambique Channel off Inhaca Island, 25°07’S, 34°34’E, International Indian Ocean Expedition, Anton Bruun, cruise 7, stn AB 372J, 19.VIII. 1964, 102 m, 1 complete and 1 anterior fragment ( LACM-AHF 2094).

TYPE LOCALITY. — Mozambique Channel.

ETYMOLOGY. — This species in named as an homage to Dr Christopher J. Glasby, for his many publications on taxonomy of polychaetes, especially for his analysis on Nereidiformia and the advice and support he has provided me on the taxonomy of pilargids.

DISTRIBUTION. — Apparently restricted to the Mozambique Channel.

DESCRIPTION

Body transparent in alcohol, complete syntype 17 mm in length, 0.5 mm in width, 62 setigers. Anterior fragment 6 mm in length, 0.4 mm width, 21 setigers, with pharynx slightly everted.

Prostomium trapezoidal; three cirriform antennae; lateral antennae placed posteriorly and slightly smaller than median, median antennae short, not reaching setiger 1, slightly more posteriorly placed. Palps biarticulated, free from each other, with small rounded palpostyles and short ventral papillae. Eyes not seen; colored granules around the base of palps. Tentacular cirri cirriform, well developed, dorsal slightly longer than the ventral one ( Fig. 6A ).

Parapodia with cirriform cirri and short setal lobes. Dorsal and ventral cirri of anterior parapodia ( Fig. 6B ) similar in length, around setiger 26, dorsal cirri become slightly shorter than the ventral ones ( Fig. 6C ), by setiger 40 ( Fig. 6D ) dorsal cirri is about 4/5 the length of the ventral ones but more posteriorly, dorsal cirri become enlarged ( Fig. 6E ). Notospines present from setiger 12, smooth, acute, with oblique line or slit over most of exposed length; length of emergent portion appears to change in relation to body region. By about setiger 21, emergent portion of notospine equal in size to dorsal cirri, spine becomes longer than dorsal cirri in posterior setigers. Pre-pygidial region has longer dorsal cirri ( Fig. 6F ). Neurosetae finely limbate capillaries, and furcate setae with asymmetric tines.

Pygidium with two anal cirri, each as long as the preceding segment; one or two asetigerous segments provided with cirriform cirri ( Fig. 6F ). The pharynx reaches setiger 4 but since anterior portion may be everted, it may be some 5- 6 setigers in length.

REMARKS

Synelmis glasbyi n. sp. is very similar to S. emiliae n. sp and to S. sinica in general appearance; they have short ventral papillae, short setal lobes, and a similar start of notospines. S. glasbyi n. sp. differs in having very short median antenna, and dorsal pigmented granules around the bases of palps. Notospines with an oblique slit area also present in S. emiliae n. sp. but in that species the spines are distally curved while in S. glasbyi n. sp. they are straight.

Synelmis gorgonensis ( Monro, 1933) n. comb. ( Figs 1D, E ; 7 )

Ancistrosyllis gorgonensis Monro, 1933: 26-28 , textfig. 12.

Ancistrosyllis rigida – Hartmann-Schröder 1965: 285- 287, figs 286-288 (non Fauvel 1919a).

Synelmis albini – Westheide 1974: 223-225, figs 12, 13 (non Langerhans 1881).

MATERIAL EXAMINED. — Eastern Pacific. St George Pacific Expedition 1923-1924, Gorgona Island, 3.00°N, 78.19°W, Colombia, St Gorgona 3, C. Crossland, holotype of Ancistrosyllis gorgonensis Monro, 1933 ( BMNH 1932.12.24.128). — Chile, Taltal, 25.24°S, 70.29°W, W. Noodt, 30.I.1959, 0.5 m, 1 anterior fragment and 2 posterior ones ( ZMH- 14211).

DISTRIBUTION. — Pacific coast of Colombia, the Galapagos Islands, and northern Chile.

DESCRIPTION

Holotype complete but several parapodia missing and body is breaking in two points: towards the middle of the body and in the posterior third of the body; about setiger 50 there is a transverse cut and another longitudinal one that does not reach the gut, but that could cause its fragmentation. The original description and later characteristics by Hartmann-Schröder (1965) and by Westheide (1974) are excellent; a few details are added here. Body pale yellow with fine transverse dark bands, especially towards the anterior end, bands coincide with the setal lobe but the preceding section is colorless. There are paired dark glands along ventral surface starting about the first third of the body. Ventral furrow shallow.

Eyes of different size, in straight transverse line, each with two eyes; external eyes larger than internal ones and left smaller one is double (each is abouth half the size of the complete one on the right side) in holotype ( Fig. 7A ). The small juvenile from Chile has lateral eyes fused into a single reniform eye, slightly behind the lateral antennae. Anterior ( Fig. 7B ), median ( Fig. 7C ), and posterior parapodia ( Fig. 7D ) with dorsal and ventral cirri very swollen, much wider than setal lobe; dorsal cirrus has its distal tip well defined and sometimes it appears jointed (even in the juvenile they are wider than the setal lobe). Most cirri have pigmented glands, appear darker than the rest of the body. Pigmented, small glandular areas behind the dorsal cirri in setigers 18-60. Interramal glands present in several anterior and posterior setigers; glands internal, can be seen above the setal lobe in lateral observation of the body.

Notospines start in setigers 9-11 (setiger 9 in juvenile). Furcate setae large but very brittle, they are apparently in the center of the setal bundle, and are slightly asymmetrical ( Fig. 1D ). Hartmann- Schröder (1965: 286, fig. 288) showed that the setal branches are asymmetrical and that they are fused by a thin blade ( Fig. 1E ). Posterior end ( Fig. 7E ) with sligthly emergent notospines, one or two asetigerous segments and two lateral anal cirri.

REMARKS

Monro (1933) noted that the type was collected from bottoms with shell debris, coral and pebbles, at 15 fathoms; he illustrated a median parapodium and showed that dorsal cirri were almost three times wider than setal lobe ( Monro 1933: text-fig. 12b). Hartman (1947) recorded some specimens from western Mexico, identified them with A. rigida Fauvel, 1919 , and regarded A. gorgonensis as a junior synonym. About the thickness of the dorsal cirri she stated ( Hartman 1947: 501): “It is possible that this [Monro] figure was made from a preparation depressed under the cover slip”. Western Mexico specimens belong to another species (see S. harrisae n. sp., below), but certainly A. gorgonensis deserves a specific status. Westheide (1974) examined two specimens and made illustrations from a living one which had longer palps and the distinction between cirrophore and cirrostyle was not clear, the eyes appear at the middle of the prostomium (not posteriorly as in the type), and the pharynx is 4-5 setigers in length. Upon fixation, palps became clearly biarticulated, eyes “moved” towards the posterior margin of the prostomium; the thickness and pigmentation of the body wall prevented observation of the pharynx length. Eyes are duplicated but the degree of fusion may vary; Westheide’s specimens had eyes completely fused while in the type they are partly fused. By comparing the drawings by Westheide (1974: 224, fig. 12C), with the figures by Monro, it could be concluded that the relative development of parapodial cirri is affected by fixation or by cover-slipe compression, as Hartman (1947) had thought, but in fact the parapodia were taken from different body regions and are not directly comparable, Monro’s are from middle and Westheide’s are from anterior regions. I conclude that they belong to the same species.

Figures

FIG. 6. — Synelmis glasbyi n. sp. from the Mozambique Channel (LACM-AHF-2094); A, anterior end in dorsal view; B, setiger 10 in anterior view; C, setiger 21 in posterior view; D, setiger 26 in posterior view; E, setiger 40 in posterior view; F, posterior end in dorsal view. Scale bars: A, F, 0.15 mm; B-E, 100 µm.

FIG. 1. — Furcate setae from different Synelmis species; A, S. britayevi n. sp. (LACM-AHF-2092); B, S. emiliae n. sp. (UANL-318); C, S. gibbsi n. sp. (BMNH-1971.65); D, E, S. gorgonensis (Monro, 1933) n. comb.; D, BMNH-1932.12.24.128; E, ZMH-14211; F, S. harrisae n. sp. (LACM-AHF-2095); G, S. rigida (Fauvel,1919) n. comb.(BMNH 1970.310); H, S. rigida n. comb. (MNHN A71); I, J, S. sotoi n. sp. (MNHN A888 As296). Scale bar: 30 µm.

FIG. 7. — Synelmis gorgonensis (Monro, 1933) n. comb. from Pacific Colombia (BMNH-1932.12.24.128); A, anterior end in dorsal view; B, anterior setiger in posterior view; C, median setiger in posterior view; D, posterior setiger in posterior view; E, posterior end in dorsal view. Scale bars: A, E, 0.25 mm; B-D, 100 µm.