Pista palmata ( Verrill, 1873 )

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 : 28-29

Pista palmata ( Verrill, 1873)

Figures 7 E–J

Scionopsis palmata Verrill, 1873:614 –615; 1881:302, Plate 11, Figure 3 . Pista palmata Hartman, 1959: 516 . Holthe, 1986a: 144; Kritzler, 1984: 52 –49 52–51, Figures 52– 47, 48a–f.

Material examined: Mexican Caribbean: ECOSUR TERE­21 (1) R/V “Edwin Link” sta. 2777, Southern Chinchorro Bank (18°26’02’’N 87°18’82’’W), 21 Aug. 1990. (1) R/V “Edwin Link” sta. 2788, Punta Changuay, Rio Indio and Ubero (18°51’74’’N 87°37’38’’W), 26 Aug. 1990. (1) QR4 Playa Aventuras (20°20’15.5’’N 87°20’31.7’’W), 21 Mar. 1992. (1) B114 Xahuayxol (18°30’15’’N 87°45’32’’W), 29 Oct. 1997. (1) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 22 Feb. 1999. (2) Sol y Mar Hotel, Majahual (18°44’14’’N 87°41’20’’W), 9 Jan. 2001, inside sponge. (2) Sol y Mar Hotel, Majahual (18°44’14’’N 87°41’20’’W), 19 Jan. 2001. (2) Majahual (18°40’09.6’’N 87°43’01.4’’W), 19 Jan. 2001. (1) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 28 Feb. 2001. (1) Leeward of Contoy Island (21°30’8.4’’N 86°47’45.3’’W), 2 Mar. 2001. (2) Rio Indio (18°54’15.4’’N 87°38’36.1’’W), 17 Mar. 2001, in seagrass.

Description: Complete specimen, body pale yellow on preserved material, thin and long, with 80 segments, 36 mm long; thorax 9 mm long, 2.5 mm wide ( Figures 7 E–F). Tentacles thin. Tentacular membrane short, covered by the first lateral lappet. Eyespots absent. Upper lip with large and folded free edge, projecting forwards. Lower lip small, swollen. Lateral lappets well developed, on segments 1 and 3; first pair of lateral lappets laterally covering tentacular membrane, ventrally exposing lower lip; second pair of lappet smaller than first pair, laterally covering segment 2. Segment 4 with two short dorsal prolongations projecting forward into the branchial cavity. Two pairs of branchiae, long branched, starting from segment 2; branchiae with long stalks, four levels of ramification, branches with short dendritic tips. Nephridial papillae not visible. Fifteen ventral shields present, almost equal­sized, starting from segment 4; anterior shields rectangular, becoming square from midthorax. Thorax with 17 well developed pairs of notopodia, starting from segment 4. Notochaetae smooth and bilimbate, distally swollen, alternating long and short within the same fascicle ( Figure 7 G). Neuropodia starting from segment 5, uncini arranged in single rows on segments 5–10, in double rows on segments 11–20, and from segment 21 until pygidium in single row. Abdominal neuropodia as long as the thoracic notopodia. Anterior and midthoracic uncini with dental formula MF:2:2–3:2–3:1 ( Figure 7 H). Uncini from segment 5 with main fang distally rounded, upper subrostrum with tipped subrostral process; without subrostral appendix; lower subrostrum slightly concave, both anterior process and anterior filament absent; basis straight finishing by develop posterior process, with long filament; occipitium long and straight; capitium with distinct teeth. Uncini from segment 8 smaller than those from segment 5, both with the same dental formula ( Figure 7 I). Uncini from segment 14 with dental formula MF:3:3:2– 3:1 ( Figure 7 J), uncini without subrostral process and with convex lower subrostrum; both anterior process and filament absent; basis very curved, with small posterior process, less prominent than in thoracic uncini; without posterior filament; occipitium depressed, short and rounded, capitium with distinct teeth. Pygidium without anal papillae. Tube long (> 70 mm), 4 mm wide, made off white coral fragments, calcareous algae, foraminifera, molluscs, and sometimes leaf of sea­grass ( Syringodium ) attached to a weak inner membrane.

Var ia t io n: Ventral shields may vary from 12 to 15.

Remarks: Kritzler (1984) recorded specimens from the upper Gulf of Mexico with single row of uncini on the first eight neuropodia; however, in the original description as well as in the Mexican Caribbean specimens, the uncini in single row occur only on the first six neuropodia. This may indicate that two different species are present in the region. Specimens from both regions must be compared in order to clarify Kritzlers observations.

Distribution: Massachusetts, Gulf of Mexico, Mexican Caribbean.

Figures

FIGURE 3. Thelepus sp. A. Ventral view; B. Lateral view; C. Chaetae from segment 22; D. Uncini in lateral view from segment 7; E. Uncini in front view from segment 7. Amphitritides bruneocomata: F. Lateral view; G. Ventral view; H. Nephridial tubes from segment 11 – 13; I. Chaetae from segment 13; J. Uncini from segment 13. Scale bars: A, B, F, G 2 mm; D, E 0.2 mm; C, I, J 0.05 mm; H 0.5 mm.

FIGURE 7. Paraeupolymnia carus: A. Lateral view; B. Chaetae from segment 4; C. Uncini in double row from segment 15; D. Uncini from segment 30. Pista palmata: E. Ventral view; F. Dorsal view; G. Chaetae from segment 15; H. Uncinus from segment 5; I. Uncinus from segment 8; J. Uncinus from segment 14. Scale bars: A, E, F 1 mm; C, D, H, I, J 0.02 mm; B, G 0.05 mm;