Thelepus verrilli ( Treadwell, 1911 ) Londoño-Mesa, 2009

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 87

Thelepus verrilli ( Treadwell, 1911) comb. nov.

Figures 27 A-H

Streblosoma verrilli, Treadwell, 1911:11–12 , Figs 27 –29A,B.— Hessle, 1917:212.— Monro, 1933:1073–1074, Text-Figs 20A-C.— Kritzler, 1984:53–63, 52–65, Figs 52–61, 62A-F.

Thelepus setosus, Holthe, 1986b:160 (partim).

Type material: Holotype AMNH 459 and Paratype AMNH 459 B (1) Fort Jefferson , Dry Tortugas, Florida, 1909 .

Additional material: Florida : USNM 17718 (1) Dry Tortugas, Florida , 1915. Mexican Caribbean : ECO- SUR TERE-25 (1) Nizuc Point, Cancun (21º02'11.7"N 86º46'44.2"W), 10.II.2001; 4m. Bermuda: UMML 22.981 (4) Northern Bermuda (30°58'N 79°42'W), R/V “Pillsbury” Sta. 105; 27.VII.1964; 395m.

Description: Holotype complete, 187 segments, 85mm long, thorax 41mm, long, 2.5mm wide; abdomen 1–1.8mm wide ( Figs 27A,B ). Thorax dorsally swollen, with many oocytes. Upper lip short, rounded, with ventral wrinkles, connecting with tentacular membrane ( Fig. 27C ). Lower lip swollen, projected ventrally, with longitudinal medial line. Tentacular membrane well-developed, with thick edge, directed laterally; small dark brown eyespots, surrounding tentacular membrane base. Few tentacles present, with deep groove. Segment 1 well-developed, laterally elongate, ventrally with two short ventral lobes covering the lower lip. Seventeen ventral shields ( Fig. 27B ), with medial groove; first 3 shields crenulated; shields from segments 2–3 thinner, half as wide as shield in segment 4; then smooth. Ventral groove along body. Three pairs of sessile, digitate branchiae ( Fig. 27D ), increasing in length; first and second pair with 2 twisted filaments at each side, half as long as last pair; last pair with 4 filaments. Notopodia long, flat; thirty-nine pairs of notopodia; notochaetae of two lengths ( Fig. 27E ), long chaetae symmetrically bilimbate distally ( Fig. 27F ), on oblique fascicle; short chaetae medially unilimbate, smoothly tipped ( Fig. 27G ). Thoracic and abdominal uncini ( Fig. 27H ) with dental formula MF:2:0–1; PP and PF absent; Oc slightly convex; Cp with one or two rows of teeth, as long as two third the MF; Sr narrow; SrP and SrA absent; LSr with a square button close to rounded AP; AF absent; Bs slightly curved. Pygidium conical, 0.4mm wide, with 12 small papillae.

Staining pattern: Only ventral shields from segment 3 stain deeply ( Fig. 27B ); first ventral shield, on segment 2, and the remaining structures do not stain ( Fig. 27C ).

Discussion: Since the original description does not match with the type specimens, they are redescribed and transferred here to Thelepus as they have the characters of the genus, such as notopodia from segment 3. Hartman (1956) considered this species to be the same as T. setosus , after checking the type specimen. This was repeated ( Hartman 1959) and followed by Holthe (1986b). Nevertheless, because of the reduced number of branchial filaments in T. verrilli comb. nov., having first and second pairs with 2 filaments, and third pair with 4 filaments, and the high number of them in T. haitiensis , first pair with 35–43 filaments, second pair with 25–30 and third pair with 20–30, and considering the comments distinguishing T. haitiensis from T. setosus (see above), these specimens cannot be assigned to either of the latter two species.

Type locality: Fort Jefferson , Dry Tortugas, Florida, USA .

Distribution: Florida, Bermuda. 4 to 395m.

Figures

FIGURE 27. Thelepus verrilli comb. nov., (Holotype AMNH 459): A. Thoracic region in dorsal view. B. Thoracic region in ventral view. C. Anterior end in ventral view. D. Anterior end in dorsal view. E. Fascicle of chaetae from anterior thoracic segment. F. Long chaeta from anterior thoracic segment. G. Short chaeta from anterior thoracic segment. H. Uncini from anterior thoracic segment. Scale bars: A,B: 3.3mm; C,D: 1.2mm; E: 0.8mm; F,G: 0.08mm; H: 0.04mm.