Amphitritides bruneocomata Ehlers 1887

Amphitritides bruneocomata (Ehlers, 1887)

Figures 3 F–J

Terebella bruneocomata Ehlers, 1887: 237 –241, Plates 51, Figures 1–5. Amphitritides bruneocomata Hartman, 1959: 499; Holthe, 1986a: 124; Arvanitidis and Koukouras, 1995: 224.

Material examined: Mexican Caribbean: UMML (1) R/V “Pillsbury” cruise 6802, sta. P588, Yucatan Channel (21°14’N 86°24’W), 14 Mar. 1968, 175 m. ECOSUR TERE­4 (QR4) (1) Playa Aventuras (20°20’15.5’’N 87°20’31.7’’W), 21 Mar. 1992, in coralline rock, 2 m. (1) Cozumel Island (20°30’35.341’’N 86°56’58’’W), 4 Jun. 1995. E2 (1) Xahuayxol (18°30’15’’N 87°45’32’’W), 26 Sep. 1996, 1.5 m. (R5) (1) Punta Nizuc, Cancún (21°02’11.7’’N 86°46’44.2’’W), 31 Aug. 1997. (1) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 1 Mar. 2001, in dead Strombus gigas conch. (1) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 3 Mar. 2001, in dead Strombus gigas conch, 3 m. (1) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), Jun. 1999. Gulf of Mexico: (2) Ría Lagartos (21°37’16.7’’N 88°10’32.6’’W), 18 Feb. 1999.

Description: Complete specimen with dark red body on preserved material, with 107 segments, 75 mm long; thorax 12 mm long, 4 mm wide (Figures 3 F–G). Body swollen for the first 18–20 segments, posteriorly tapering. Groups of small eggs inside the coelomic cavity of the last three thoracic notopodia until up to 15 segments before pygidium. Tentacles brown, of two sizes, thinner at the base. Tentacular membrane well­developed. Eyespots absent. Upper lip with short, cushion­like free edge, projecting forwards. Lower lip small, swollen. Lateral lappets absent. Two pairs of equal­sized branchiae, weakly branched, with short stems and tips; sometimes reddish, placed on segments 2 and 3. Nephridial papillae on segments 3 and from 6–21, inserted posteriorly to notopodia, each papilla as a long pale trumpet­like tube as long as notopodia (Figure 3 H). Notopodia on chaetigers 1–15 surrounded by white glandular tissue. Fifteen to 16 ventral shields, starting from segment 1; first one swollen, below lower lip; anterior shields rectangular, becoming square and narrow on posterior thoracic segments; with a deep and narrow groove from segment 16–17 until the end of the body. Notopodia from segment 4–31. Notochaetae consisting of two types, long chaetae distally denticulate and subdistally bilimbate, with wide limbs (Figure 3 I); and short chaetae distally denticulate and subdistally bilimbate with narrow limbs. Neuropodia from segment 5, uncini arranged in single rows from segment 5–9, then in double rows, in face to face position until near posterior end. Uncini with dental formula MF:4–5:5–6:3–4 (Figure 3 J). Uncini with long main fang, forming a rounded upper subrostrum, subrostral process tipped, without evident subrostral appendix; lower subrostrum convex; both anterior process and filament absent; concave basis ending into evident posterior process, without posterior filament; occipitium almost straight, with upper toothed capitium, teeth progressively longer towards main fang. Pygidium short, surrounded by 5 or 6 anal papillae. Tube small, 5 mm wide, made of tiny fragments of coral rubble and foraminifera, attached to a thin brown membrane; some found attached to shells.

Variation: The number of thoracic chaetigers varies between 22 and 28 segments in some of the material examined.

Remarks: Day (1973) stated that A. bruneocomata is the same species as Terebella pterochaeta Schmarda, 1861, from South Africa, considering that both the number of thoracic chaetigers and uncinal teeth are variable characters in Terebella. However, Holthe (1986a) and Arvanitidis & Koukouras (1995) regarded A. bruneocomata as a valid species.

Distribution: Southern Florida, Gulf of Mexico, Mexican Caribbean and West Indies.