Streblosoma tenhovei, Londoño-Mesa, 2009

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 76-77

Streblosoma tenhovei sp. nov.

Figures 22 A-G

Type material: Holotype ZMA V.Pol. 1642 and Paratypes (9) Curaçao, St. Joris Baai , S shore SE, 23.X.1968; sandy, rock debris, Thalassia .

Additional material: Mexican Caribbean : Quintana Roo State: ECOSUR TERE-17 HOL10 (1) Holbox, Mexican Caribbean , 3.VI.2005.

Etymology: This species is dedicated to Dr. Harry ten Hove, because of his many publications involving Caribbean polychaetes and especially because of his support by loaning excellent material from the Grand Caribbean region.

Description: Holotype incomplete, 23 segments, 8mm long, 0.7mm wide. Tentacular membrane short, with thick edge ( Fig. 22A ); 8–9 dark eyespots, placed only latero-ventrally. Tentacles long, thin. Upper lip reduced, rounded. Lower lip swollen, in front of swollen pharyngeal organ ( Fig. 22B ). Fourteen ventral shields, decreasing in size; first one one third as long as second shield ( Fig. 22C ). Three pairs of long digitate branchiae; all placed dorsally to notopodia, near posterior border of each segment, without swollen bases ( Fig. 22D ); first pair with 1 branchial filament at each side, second pair with 4 filaments at each side, and third pair with 9 filaments (left branchia lost). Twenty-two pairs of notopodia; notochaetae of two intercalated lengths, long chaetae asymmetrically bilimbate ( Fig. 22E ), short chaetae thinner, unilimbate ( Fig. 22F ). Pairs of neuropodia with thoracic and abdominal avicular uncini ( Fig. 22G ), with dental formula MF:2–3:3–5; PP and PF absent; Oc slightly convex; Cp with two horizontal lines of teeth over the MF; first line with two or three teeth as long as one half the MF, the middle one, when present, shorter than others; second line with two or three smaller teeth, as long as half the length of the longest tooth in first row; Sr narrow; SrP as square button near to rounded AP; LSr narrow; AF absent; Bs slightly curved. Pygidium absent.

Staining pattern: Only ventral shields stain deeply ( Figs 22B,C ); the remaining structures do not stain.

Variations: The other specimens are incomplete, but with more segments, having 20–29 chaetigers, 7– 13mm long, thorax 0.4–0.8mm wide at segment 5, 0.3mm on segment 70 in the longest specimen, and up to 15 ventral shields. The number of branchial filaments varies from 1–2 on first pair, 2–4 on second pair, and 4– 9 on third pair. One specimen has the third pair of branchiae on the inter-segmental line, between segment 4 and 5; another specimen lacks the third pair (but scars on segment 5); nevertheless, the blood vessel seem to come from segment 4.

Discussion: Streblosoma tenhovei sp. nov., differs from S. hartmanae by having eyespots restricted to the lateral sides of the tentacular membrane, in two well-separated groups; by the reduced number of branchial filaments, and by their relative position being placed dorsally and posteriorly to the notopodia, and next to the inter-segmental line of the next segment; each pair of branchiae without swollen bases. Further, Streblosoma tenhovei sp. nov., has more accessory teeth on the last row of teeth. In contrast, S. hartmanae has more branchial filaments emerging from a swollen base, placed anteriorly to notopodia and next to the anterior intersegmental line.

Type locality: Curaçao, Lesser Antilles .

Figures

FIGURE 22. Streblosoma tenhovei sp. nov., (Holotype ZMA V.Pol. 1642): A. Thoracic region in dorsal view. B. Anterior end in ventral view. C. Thoracic region in ventral view. D. Anterior end in dorsal view. E. Long chaeta from anterior thoracic segment. F. Short chaeta from anterior thoracic segment. G. Uncini from anterior thoracic region. Scale bars: A,C: 1.4mm; B,D: 0.5mm; E,F: 0.05mm; G: 0.02mm.