Eupolymnia crassicornis ( Schmarda, 1861 )

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 : 13-15

Eupolymnia crassicornis ( Schmarda, 1861)

Figures 4 A–C

Terebella crassicornis Schmarda, 1861: 43 , text­figures a–c.

Eupolymnia crassicornis Hartman, 1959: 504 ; Rullier, 1974: 67–68; Holthe, 1986a: 127.

Material examined: Mexican Caribbean: ECOSUR TERE­24 (1) Ascensión Bay, 6 Oct. 1983. (1) Southern Cozumel Island (20°17’28”N 86°57’28’’W), 10 Oct. 1983, 2 m. (1) Puerto Morelos (21°36’53.2’’N 87°04’31.9’’W), 6 Feb. 1986, 2 m. (1) Chinchorro Bank (18°35’51.0’’N 87°20’20.5’’W), 28 Jul. 1990. (1) Cozumel Island (20°30’35.341’’N 86°56’58’’W), 4 Jun. 1995, 2 m. (4) E55 Majahual (18°40’09.6’’N 87°43’01.4’’W), 3 Oct. 1996, 2 m. (1) Xahuayxol (18°30’15’’N 87°45’32’’W), 29 Oct. 1997. (1) Majahual (18°40’09.6’’N 87°43’01.4’’W), 4 Dec. 1998, 2 m. (1) Leeward of Contoy Island (21°30’ 8.4’’N 86°47’45.3’’W), 23 Jan. 1999. (3) Playa Aventuras (20°20’15.5’’N 87°20’ 31.7’’W), 28 Feb. 1999, 2 m. (1) Majahual (18°40’09.6’’N 87°43’01.4’’W), 1 Jan. 2001, 2.5 m. (1) Punta Nizuc, Cancún (21°02’11.7’’N 86°46’44.2’’W), 10 Jan. 2001, 4 m. (1) Punta Nizuc, Cancún (21°02’11.7’’N 86°46’44.2’’W), 10 Feb. 2001, 2 m. (4) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 1 Mar. 2001, 2.5 m. (1) Southern, Contoy Island (21°27’33’’N 86°46’06’’W), 2 Mar. 2001, 2 m, in coralline rock. (3) Xahuayxol (18°30’15’’N 87°45’32’’W), 2 Aug. 2002, 1.5–2 m, in coralline rock. Gulf of Mexico: (6) Pérez Island reef, 26 Jun. 1988, 2 m. Antilles: LACM­AHF (2) La Parguera, Fosforescente Bay, Porto Rico, 15 Mar. 1955. ZMA V.POL. 1123 (4) Cayo Caracoles, La Parguera, Fosforescente Bay, Porto Rico, 8 Feb. 1963. ZMA V.POL. 1129 (1) Porto Rico, 14 Feb. 1963.

Description: Complete specimen mature female, with light brown body on preserved material, with 88 segments, 80 mm long; thorax 25 mm long and 11 mm wide ( Figure 4 A). Thorax swollen, tapering posteriorly; abdomen narrower than thorax, with visible segmentation. Eggs in coelom of thoracic segments. Abdomen with midventral longitudinal groove. Tentacles long. Narrow tentacular membrane, surrounding the base of tentacles, visible on ventral side; eyespots abundant, dark, small, in one line all along the posterior tentacular membrane. Upper lip with free edge projecting forwards, well developed, spoon­shaped, with a stout base. Lower lip visible, large and swollen, ventrally limited by marginal lobes of tentacular membrane. Three pairs of lateral lappets from segment 2, the first narrower than the others; second and third pairs equal­sized; each with lateral swollen and folded membrane. Three pairs of branchiae, reddish, branched, on segments 2–4, decreasing in size posteriorly, the first pair almost twice as large as the second, and the second twice as large as the third pair. Branchiae with three or four levels of ramification, with short digitate terminal filaments. Nephridial papillae large, bulbous, on segments 3–5, placed next posteriorly to notopodia. Notopodia surrounded by white swollen papillate tissue on segments 3–4 to 13–14. Ventral shields pale, present over 14– 15 segments, laterally enlarged, starting from segment 2; posterior thoracic shields reduced; all shields with many folds and wrinkles. Notopodia from segment 4, thorax with 17 chaetigers. Notochaetae bilimbate and pointed ( Figure 4 B), each chaeta darker at the base, with some longitudinal striations. Dorsal chaetae longer than ventral chaetae in the same notopodia. Neuropodia present from segment 5, uncini arrange in single rows on segments 5–9, in double rows on segments 10–20, in face to face position; arrange in single rows from segments 21 until the end of the body. Thoracic neuropodia three times as long as abdominal ones. Abdominal neuropodia well developed, as swollen lappets with short rows of uncini, sometimes straight or semi­curved. Thoracic and abdominal uncini similar in shape and size. Uncini with dental formula MF:3:4 ( Figure 4 C); upper subrostrum formed by the main fang and a well­developed subrostral process; lower subrostrum concave ending in a short, pointed anterior process, without anterior filament; curved basis with developed posterior process, with posterior filament; long and concave occipitium; capitium with 2 rows of teeth above main fang, the first with 3 long teeth, the second with 4 smaller teeth. Pygidium circular, with around 20 anal papillae. Tube constructed of large fragments of coral and shell, red and white foraminifera, all of this attached and wrapping around an inner fragile membrane; the tube can be more than 250 mm long and 20 mm wide, curve; anterior and posterior ends are open and equal­sized.

Var ia t io n: The total number of segments in specimens complete and revised varies from 88 to 137 segments.

Remarks: This species differs from E. nebulosa ( Montagu, 1818) in the color, and by the presence of five first segments on the thorax with uncini arranged in single rows, instead of six. Beside, E. crassicornis has thorax broader than E. nebulosa .

Distribution: Common in the Grand Caribbean Region.

Figures

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.