Eupolymnia nebulosa ( Montagu, 1818 )

Londoño-Mesa, Mario H. & Carrera-Parra, Luis F., 2005, Terebellidae (Polychaeta) from the Mexican Caribbean with description of four new species, Zootaxa 1057, pp. 1-44 : 15-17

Eupolymnia nebulosa ( Montagu, 1818)

Figures 4 D–F

Terebella nebulosa Montagu, 1818: 343 , Plate 12, Figure 2 . Eupolymnia nebulosa Hartman, 1959: 504 ; Kritzler, 1984: 52 –57, Figures 52–53, 54a–d; Holthe, 1986a: 128.

Material examined: Mexican Caribbean: ECOSUR TERE­10 (1) Mujeres Island (21°13’39.7’’N 86°43’53.5’’W), 26 May 1962. (1) Puerto Morelos (21°36’53.2’’N 87°04’31.9’’W), 13 Sep. 1986. (2) Playa Aventuras (20°20’15.5’’N 87°20’31.7’’W), 22 Mar. 1992, 2 m, under coralline rock. (1) QR7 Chankanaab, Cozumel Island (20°56’38’’N 86°59’35’’W), 2 Apr.1992. (2) QR8 Xcacel (20°20’16’’N 87°20’52’’W), 3 Apr. 1992, below coralline rock. (1) M27 Xahuayxol (18°30’15’’N 87°45’32’’W), 1 Oct. 1996. (3) Xahuayxol (18°30’15’’N 87°45’32’’W), 1 Oct. 1996. (1) Isla Blanca (21°20’16.8’’ N 86°47’40.4’’W), May 1997. (2) Majahual (18°40’09.6’’N 87°43’01.4’’W), 21 Jul. 1998, 1.5 m. (5) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 23 Feb. 1999. (3) Playa Corona, Cozumel Island (20°27’45’’N 86°59’04’’W), 25 Feb. 1999. (2) Majahual (18°40’09.6’’N 87°43’01.4’’W), 21 Mar. 2000. (1) Majahual (18°40’09.6’’N 87°43’01.4’’W), 22 Mar. 2000, 2 m. (19) Southern, Contoy Island (21°27’33’’N 86°46’06’’W), 28 Feb. 2001. (2) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 1 Mar. 2001. (4) Southern, Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 2 Mar. 2001. (1) Contoy Island (21°30’8.4’’N 86°47’45.3’’W) 3 Mar. 2001. (1) Rio Indio (18°54’15.4’’N 87°38’36.1’’W), 17 Mar. 2001, in seagrass. (1) Majahual (18°40’09.6’’N 87°43’014’’W), 18 Mar. 2001. (1) Playa Azul, Cozumel Island (20°32’07’’N 86°56’10’’W), 25 Mar. 2001. (1) Southern Cozumel Island (20°17’28’’N 86°57’28’’W), 26 Mar. 2001, 3 m. (8) Majahual (18°40’09.6’’N 87°43’01.4’’W), 18 May 2002, in dead coral. (3) Xahuayxol (18°30’15’’N 87°45’32’’W), 2 Aug. 2002, 1.5– 2 m. (1) R/V “Edwin Link”, sta. 2772, Isla de la Pasión, Cozumel Island (20°39’59’’N 86°49’64’’W), 19 Aug. 1990. (1) R/V “Edwin Link”, sta. 2777, Southern Chinchorro Bank (18°26’02N 87°18’82W), 21 Aug. 1990. (4) R/V “Edwin Link”, sta. 2792, Eastern Mujeres Island (21°14’N 86°36’W), 28 Aug. 1990.

Description: Specimen complete, with 127 segments, 160 mm long; thorax 15 mm long, 6 mm wide ( Figure 4 D). Tentacles pale, long, numerous. Tentacular membrane dorsally reduced and with visible lateral lobes, aside of lower lip. Eyespots dark, small, less pigmented anteriorly. Upper lip with free edge as a thin spoon­like membrane, projecting forwards. Lower lip always well developed, swollen or thin. Three pairs of lateral lappets from segment 2. First lappet longer and ventrolateral; second and third pair as short lateral folds; third pair shorter in height, close to first pair of notopodia. Three pairs of branchiae on segments 2–4, first pair at least twice as long as the second, last pair the shortest, about one fourth the size of the first; branchiae with 3 levels of ramification, with long transparent filaments; last pair of branchiae with short and spiraled filaments; branchiae with short and stout stalks. Seven pairs of nephridial papillae present; starting on segment 3; the first one three times as long as the other papillae, present between the bases of branchiae and first pair of lateral lappets. Following papillae present between noto­ and neuropodia; papilla as short tube, like truncate cones. Ten ventral shields, starting from segment 3, very distinct; shields rectangular, anterior ones broader, progressively narrowing along the thorax; the second ventral shield extending laterally joining the first pair of lateral lappets. Abdomen with thin and long ventral shields, reaching up to the pygidium, and forming midventral groove. Notopodia present from segment 4 extending through 17 segments. Notochaetae long bilimbate ( Figure 4 E). Dorsal chaetae longer than ventral chaetae. Neuropodia with uncini arranged in single rows from segment 5 to 10; in double rows from segment 11–20, arranged in face to face position; abdomen with uncini arranged in single rows to the pygidium; abdominal neuropodia well developed but short, one third as long as thoracic ones, with uncini on the anterior face, main fang anteriorly pointed. Thoracic and abdominal uncini similar to each other; uncini with dental formula MF:2:3 ( Figure 4 F); upper subrostrum formed by the main fang and well­developed, rounded subrostral process; lower subrostrum concave finishing in a curved anterior region, without anterior process or filament; curved basis, finishing into a short posterior process, without filament; long and concave occipitium finishing into a capitium with two long teeth above the main fang and a second row with three teeth. Pygidium circular, with 18–19 anal papillae. Tube 200 mm long, 15 mm wide, curved; with big fragments of coral, shells, red and white foraminifers, and calcareous algae, all attached and wrapping around an inner fragil membrane. Anterior end broader. Animal lives under coralline rocks, in contact with the sediment. Live specimens long, with reddish transversal lines in each segments, or yellowish with brown lines.

Var ia t io n: The total number of segments in all specimens complete revised varies from 85 to 140 segments.

Remarks: The specimens from the Mexican Caribbean do not differ from those belong to the North Sea (BMNH 1910.2.1./45/6, BMNH 1969.56, BMNH 1971.137, LACM­ AHF SMF4647, ZMA VPOL2470, ZMA VPOL1158 ZMA VPOL1159). E. nebulosa seems to be a species with a wide distribution, and morphology alone can not separate populations into different species. It is possible that future molecular studies will demonstrate that E. nebulosa is in fact a complex of sibling species.

Distribution: Amphi­Atlantic.

Figures

FIGURE 2. Streblosoma hartmanae: A. Dorsal view; B. Ventral view; C. Lateral view; D. Chaetae from segment 11; E. Uncini in lateral view from segment 11; F. Uncini in front view from segment 11. Thelepus haitiensis: G. Lateral view; H. Ventral view; I. Chaetiger from segment 10; J. Chaetae from segment 10; K. Uncini from segment 10. Scale bars: A, B, C, 0.5 mm; D, 0.03 mm; E, F, 0.02 mm; J, K 0.05; G, H 2 mm; I 0.2 mm.

FIGURE 4. Eupolymnia crassicornis: A. Lateral view; B. Chaeta from segment 5; C. Uncinus from segment 5. Eupolymnia nebulosa: D. Lateral view; E. Chaeta from segment 10; F. Uncinus from segment 10. Loimia medusa: G. Lateral view; H. Ventral view; I. Chaeta from segment 8; J. Uncinus from segment 8. Scale bars: A 4 mm; B, E, I 0.05 mm; C, F, J 0.02 mm; D, G, H 2 mm.