Pista palmata ( Verrill, 1873 ), 1951

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 50-52

Pista palmata ( Verrill, 1873)

Figures 14 A-L

Scinopsis palmata, Verrill, 1873:320 .

Pista palmata, Hartman, 1951:112 .— Renaud, 1956:34.— Day, 1973:119–120.— Kritzler, 1984:52–49 to 52–51, Figs 52– 47, 52–48A-F.— Londoño-Mesa & Carrera-Parra, 2005:28–29 ; Figs 7 E-J.

Type material: Syntypes Scionopsis palmata YPM 49 (2) Beesley’s Pt. N.V., IV.1871, YPM 2746 (6) Thimble Is. Brandford, Connecticut (no more data) .

Additional material: Florida: AMNH 4039 (1) Pelican Island , Florida. II.1981. Gulf of Mexico: Veracruz State: UANL 5492 (1) Blanca , 14.IV.2002; Pl.1. UANL 5494 (3) Blanca, 14.IV.2002; Pl. 1 . Campeche State: ECOSUR TERE-20 CHA-14 (2) Champoton , 16.II.1999. TERE-20 (3) Champoton, 16.II.1999. Mexican Caribbean : Quintana Roo State: ECOSUR TERE-20 (1) Southern Chinchorro Bank, R /V “ Edwin Link ” Sta. 2777 (18°35'51"N 87°20'20.5"W), 21.VIII.1990; 237.4m. TERE-20 (1) Changuay Point, Rio Indio and Ubero, R/V “Edwin Link” Sta. 2788; 26.VIII.1990; 243.8m. TERE-20 QR4 (1) Aventuras Beach (20°20'15.5"N 87°20'31.7"W), 21.III.1992. TERE-21 B114 (1) Xahuayxol, 29.X.1997. TERE-20 (1) Camping, Contoy Island (2130'08.4"N 86°47'45.3"W), 22.II.1999. TERE-20 (2) Sol y Mar, Majahual , 9.I.2001, inside sponge. TERE-20 (2) Sol y Mar, Majahual, 19.I.2001. TERE-20 (1) Camping , Contoy Island (21°30'08.4"N 86°47'45.3"W), 28.II.2001. TERE-20 (1) Camping, Contoy Island (21°30'08.4"N 86°47'45.3"W), 2.III.2001. TERE-20 (2) Rio Indio , 17.III.2001, in seagrass. Panamanian Caribbean : ECO- SUR TERE-20 (2) Club Nautico , Colon, 3.VI.2002 .

Description: Best syntype YPM 2746 incomplete, in two fragments, anterior fragment with 34 segments, 16mm long; thorax 10.5mm long, 3.1mm wide ( Fig. 14A ). Posterior fragment with 59 segments, 27mm long. Tentacular membrane reduced, shorter than lateral lappets on segment 1 ( Fig. 14B ); eyespots absent; tentacles absent. Upper lip as short as tentacular membrane. Lower lip small, just visible ventrally. First pair of lateral lappets well-developed, rounded and long laterally; second pair the smallest, only small lateral lobes of ventral shield on segment 2; third pair of lateral lappets well-developed, shorter than first pair, but more dorsal. Segment 4 with dorsal edge well-developed, having two short dorsal lobes projected forward into branchial pit ( Fig. 14C ). Segments 4–6 with small ventral lappets, membranous, as lateral development of ventral shields, projecting forwards, and connecting neuropodia with ventral shield. Two pairs of branchiae from segment 2, long, dichotomously branched; branchiae with long stalks, four levels of ramification, branches with short dendritic tips. Nephridial papillae rounded on segments 6–7, dorsally and posterior to notopodia. Sixteen ventral shields, almost equal-sized, from segment 2; three anterior shields shorter, next shields rectangular and squared, of similar size. Notopodia well-developed; notochaetae smooth and symmetrically bilimbate, subdistally swollen, distally beaked, alternating long and short in same fascicle ( Fig. 14G ). Thoracic uncini from the first 3 pairs of neuropodia ( Figs 14 H-J) MF:2:1–2:1–2; from segment 5 PP developed; PF long; Oc long and straight; Cp with distinct teeth over a MF distally rounded; USr with tipped SrP; SrA absent; LSr somewhat concave, both AP and AF absent; Bs straight. Uncini on segment 8 ( Fig. 14K ) smaller than those from segment 5, with longer flat Bs; PF shorter and thinner than those in previous neuropodia; with same dental formula. Uncini from segment 11 MF:2–3:3:1–3, PP small, less prominent than on posterior thoracic uncini; PF absent; Oc depressed, short and rounded; Cp with distinct teeth over MF; SrP short, angular; SrA foliose, long, next to the main fang tip; LSr slightly convex; AP and AF absent; Bs slightly convex. Abdominal uncini ( Fig. 14L ) smaller, MF:2–3:2:1–2, PP absent; PF long, thin; Oc concave, short; Cp with distinct teeth over the MF; Sr narrow; SrP and SrA absent; AP absent; AF thin, long; Bs convex. Pygidium without anal papillae.

Staining pattern: The first three pairs of lateral lappets stain deeply ( Figs 14D,E ); margin of first pair faintly stained, and margin of third pair stains more strongly ( Figs 14D,F ); ventral shields stain from the first one, but the first three shields are slightly lighter that the rest ( Fig. 14E ). Other structures do not stain.

Variation: Syntypes YPM 49 are incomplete, one has 77 segments, 35mm long, thorax 9.7mm long, 2mm wide, and the other is 12mm long, thorax 8.4mm long, 1.5mm wide. Two syntypes YPM 2746 are complete, one of them is described above, and the other one is complete, 26mm, still in tube. Four more syntypes YPM 2746 are incomplete with thorax 6.5–10mm long, 1.5–2.1mm wide, on average. Only one specimen from the material examined (AMNH 4039), is complete and close to the size of the described specimen; it has 93 segments, 27mm long. Incomplete specimens are common in Pista species ; although they are small to mediumsized specimens, they have the ability to attach firmly to the internal tube walls, with tubes narrow relative to body width of occupant. The thoracic length is 7–9mm, and the width is 1.0– 2.5mm. Also, the number of ventral shields is 12–18.

Discussion: The records for this species from the Grand Caribbean region are limited. Hartman (1951) reported some specimens from Florida and Louisiana; she mentioned that the thoracic uncini from the first segments have a long PP, and those farther back (with uncini in double rows) have a shorter PP. Also, she mentioned that the second pair of lateral lappets (in fact, the third) meet mid-dorsally and have a pair of digitate lobes that are separated from each other medially by a short gap. These features match with the specimens examined in this study. Renaud (1956) reported specimens from Biscayne Bay, with short and incomplete description; she mentioned uncini from the first unciniger having long handles (posterior process, PP), but she did not describe the uncini from the remaining uncinigers, and the dorsal lobes on segment 3. Day (1973) gave no further information, apart from its distribution. On the other hand, the specimens reported by Kritzler (1984) do not belong to this species, because they have the first 8 pairs of neuropodia with uncini arranged in single rows, and not 6 as Verrill (1873) states in the original description. Kritzler found 18 specimens with this character, which could mean that it is not the result of ontological development. Kritzler’s (1984) specimens had two dorsal lobes on segment 3, which means that they may represent an undescribed species of the genus.

Type locality: New England , Great Egg Harbor to New Haven and Vineyard Sound, USA.

Distribution: Connecticut, Rhode Island, Massachusetts, Florida, Gulf of Mexico, and Mexican Caribbean . Intertidal to 243m.

Figures

FIGURE 7. Eupolymnia crassicornis: A. Anterior end. B. Chaeta. C. Uncinus (improved from Schmarda, 1861). Eupolymnia magnifica (Syntype USNM 4799): D. Anterior thoracic region in lateral view. E. Anterior end in lateral view. F. First seven parapodia in lateral view. G. Branchiae: longer (right) from segment 2, shorter (left) from segment 4. H. Bilimbate notochaetae from segment 10. I. Uncinus from segment 5. J. Uncinus from segment 11. K. Uncinus from segment 25. Eupolymnia nebulosa (NHM 1910.2.1): L. Bilimbate notochaeta from segment 11. M. Uncinus from segment 5. N. Uncinus from segment 11. O. Uncinus from segment 25. Scale bars: A,B,C: No original scale; D: 6mm; E,F: 3.6mm; G: 6mm; H,L: 0.9mm; I-K,M-O: 0.08mm.

FIGURE 14. Pista palmata (Syntype YPM 2746): A. Anterior thoracic region in ventral view. B. Anterior end in ventral view. C. Anterior end in dorsal view. D. Staining pattern of anterior thoracic region in lateral view. E. Staining pattern of anterior end in ventral view. F. Staining pattern after one day of anterior thoracic region in lateral view. G. Bilimbate notochaetae from segment 11. H. Uncinus from segment 5. I. Uncinus from segment 6. J. Uncinus from segment 7. K. Uncinus from segment 8. L. Uncinus from segment 25. Scale bars: A,D,E,F: 2.3mm; B,C: 2mm; G: 0.06mm; H-L: 0.04mm.