Pista cetrata ( Ehlers, 1887 ) Londoño-Mesa, 2009

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 47-50

Pista cetrata ( Ehlers, 1887) comb. nov.

Figures 13 A-N

Terebella cetrata Ehlers, 1887:248–253 , Pl. 52, Fig. 8–13 (not Fig. 14 ).— Hessle, 1917:163. Hartman, 1938:18.

Nicolea cetrata, Hartman, 1959:512 .— Perkins & Savage, 1975:54.— Holthe, 1986b:138.— Salazar-Vallejo, 1996:32.

Type material: Holotype MCZ 834 ( Nicolea cetrata ) Key West , Florida, Blake Exp. 1877–1878; 1.8–3.6m.

Additional material: Florida: UMML 22.1010 (1) Florida Strait (24°31'N 80°51'W), R/V “Gerda” Sta. 482; 26.I.1965; 205m. Gulf of Mexico: Campeche State: ECOSUR TERE-7 HUE1 (1) Hueso, 25.V.2005. TERE-7 CUY1 (4) Sabancuy (20°05'40.8"N 90°28'51.8"W), 26.V.2005; in bottom sediment, 0.7m. TERE-7 CUY2 (4) Sabancuy (20°05'40.8"N 90°28'51.8"W), 26.V.2005; in algae and sponges; 0.7m. Antilles: ZMA V.Pol. 1007A (1) Aruba, Rif Boekoeti, S. Point, 17.I.1949; Rhizophora , sand; tidal and lower zone. ZMA V.Pol. 7565 (3) Bonaire, 1–3.IX.1975; in Batophora . ZMA V.Pol. 7541B (1) Curaçao, Awa di Oospunt, hylech, 14.IX.1975; 3– 4m. UMML 22.1011 (1) Guadeloupe, Lesser Antilles, (16°26'N 61°36'W), R/V “Pillsbury” Sta. 943; 17.VII.1969; 31m. AMNH 1265B (4) Milford Bay, Tobago, (inside vial identified as Loimia medusa AMNH 1265 , but actually Lanicola carus ). USNM 54241 (1) Jobos Bay, Puerto Rico, Sta. IV, 23.VII.1976; in fine mud substrate (as Pista prob. palmata ). USNM 54961 (2) Guayanilla, Puerto Rico, Sta. VII, 21.X.1976 (as Pista palmata ).

Description: Holotype complete, 57 segments, 23mm long, thorax 11mm long, 2mm wide ( Figs 13 A-C). Tentacular membrane short; eyespots absent. Some tentacles attached, short, pale ( Fig. 13D ). Upper lip short with swollen edge; lower lip wide, swollen. First pair of lateral lappets with lateral edges well developed, covering tentacular membrane and base of upper lip; ventral edge thinner, V-shaped, covering the lower lip. Second pair reduced, lateral edges flattened, small, and connected to a thin ventral shield. Third pair long, lateral edges wider, dorsally closer than those in segment 1. Fourth pair short, membranous, connected to ventral shield; dorsally fused forming swollen margin with two rounded foliose lobes, separated by thick and wide mid-dorsal tissue. Two pairs of nephridial papillae, not easy to see, on segments 6–7, rounded, swollen, placed dorsally and posteriorly to notopodia. Eleven ventral shields from segment 3; first and second shields shorter but wider, decreasing in size up to fifth shield; then of similar size to last, swollen and separated from each other. Two pairs of branched branchiae on segments 2–3; pairs incomplete, only with the right branchia from the first pair, short, with thick wrinkled stalk. Chaetae of one length, bilimbate and distally beaked ( Fig. 13H ); first pair of notopodia shorter, dorsally closer than others. Uncini from segments 5–10 ( Fig. 13I ) MF:2:3–4:5– 7, PP thick, long tapered PF, with rounded tip; Oc long, slightly convex; Cp with small teeth over long MF; Sr long and straight, thick SrP, SrA absent; AP and AF absent; Bs slightly curved, finishing in the PF. Uncini from segments 11–20 ( Fig. 13J ) MF:3:3–4:4, PP and PF; Oc long, slightly convex; Cp with small teeth over a long MF; USr and LSr concave, divided by short, triangular SrP; SrA rounded, reaching MF tip; AP curved under Bs, AF not visible; Bs slightly convex. Abdominal uncini smaller ( Fig. 13K ) MF:3:2:2–3, PP short, rounded, PF long and thin; Oc short, concave; Cp with three series of teeth decreasing in size above the MF; those from the first row above MF with middle tooth longer than lateral ones; Sr slightly concave, SrP and SrA absent; AP long, translucent; AF long, thin, also translucent; Bs convex. Pygidium smooth ( Fig. 13L ).

Staining pattern: The first three pairs of lateral lappets stain deeply, without any difference between their edges and bases. ( Figs 13M,N ). Ventral shields stain from segments 2–17; the first 4 shields stain completely, and rest only in a central square. Dorsally, the notopodial glandular tissue stains deeply from dorsal lobes on segment 4, near to first pair of notopodia, up to end of thorax. Only the branchial stalks stain. Nephridial papillae do not stain.

Variation: The poor condition of the type specimen obscures some important characters; nevertheless, they are complemented with additional specimens examined. Some variation in the thoracic length and width was found among the additional specimens examined. Thorax is 13–22mm long, and 1.8–3.5mm wide, according to the information when collected. All specimens have a dark cavity in the center of the internal side of the third lateral lappet ( Figs 13 E-G); this cavity is open dorsally and is not easy to see, especially in poorly relaxed specimens or in poor condition, as is the case of the type specimen where this feature is hidden but present. This feature is not present in any other species of Pista reported here or anywhere, and may represent a useful character to distinguish species. Additional specimens also have short ventral lappets on segments 5 and 6, folded anteriorly, and connecting ventral shields with the tori; these ventral lappets are not seen in the type specimen because of its state of preservation. Some specimens have ventral shields from segment 2, along 15 segments; however, one specimen from Tobago has 17 ventral shields. The type specimen does not have complete branchiae; in other specimens they are heterogeneous in length, with one branchia of a pair longer than the other. The only variation presented in the color of the specimens appears in one specimen from Curaçao; its third pair of lateral lappets is light brown where the internal cavity is present, and its dorsal lobes in segment 4 are brownish. Finally, a variation in the uncinal formula, MF:2:3–4:2:1, is present .

Discussion: This species was described as Terebella cetrata by Ehlers (1887) mainly because of the two pairs of branchiae and the shape of the uncini MF:2:3. However, Hessle (1917) mentioned that it could belong to Pista , but without any further comment. Hartman (1938) followed Hessle, but later on she changed her view ( Hartman, 1959), considering this species better placed in Nicolea , presumably because of the characteristic uncinal shape of this genus, and the absence of capillary chaetae with serrated tips (common in Terebella ). Nevertheless, after the revision of the type specimen in the MCZ, I have confirmed that the species belongs to Pista , as Hessle had indicated, because of the presence of well-developed lateral lappets on segments 1–4, pairs of nephridial papillae only in segments 6–7, and the presence of uncini with long posterior process from the first unciniger, which are distinctive features of Pista . Further, after revision of the uncini, I noticed that Ehlers’ drawings were confused because the uncini in his plate 52, numbered as 8a-b, actually belong to P. cetrata (as Terebella cetrata ), and not to Terebella reticulata as said in the legend; likewise, the uncini numbered as 14a-b, also belong to the latter species.

Pista cetrata ( Ehlers, 1887) comb. nov., differs from the other species described from the Grand Caribbean region in the shape of the dorsal edge of segment 4, by the presence of uncini with a long posterior process on the first 6 pairs of neuropodia, and by having a particular staining pattern. On the other hand, this species is similar to Pista quadrilobata ( Augener, 1918) from Southern Africa, but recorded by Day (1973) from North Carolina, and by Kritzler (1984) from the Northern Gulf of Mexico, with regards to the shape of the uncini from the first pair of neuropodia. Day (1973) drew an uncinus with a long occipitium (neck), without sub-rostral process, and with a long posterior process (shaft) from specimens collected in North Carolina. Nevertheless, he mentioned that they were present only on first and second tori. Pista cetrata has this kind of uncini on the first 6 pairs of neuropodia. Other differences between these two species are the presence of eyespots, and the absence of dorsal lobes in segment 4, which are present in P. quadrilobata . The specimen reported by Kritzler (1984) as P. quadrilobata differs from P. cetrata in that the former was described as having eyespots, 18 pairs of notopodia, and uncini with a long occipitium and a posterior process only on the first three uncinigers. Kritzler’s drawings do not show the dorsal lobes in segment 4. Thus, P. cetrata differs from other Pista species originally described or reported from the Grand Caribbean region by having an internal blind cavity in the third pair of lateral lappets, short and swollen dorsal lobes on segment 4, by lacking eyespots, and by having uncini only from the first six uncinigers with long Oc, a long PP and PF, and a particular staining pattern.

One specimen from Guadeloupe had three Haplosyllides (Syllidae) , possible H. floridana , attached laterally to the abdomen, by a thin filament coming from the pharynx, and joining the mouth of the syllid with the interior of the terebellid, in regions where the latter is damaged. According to Martin and Britayev (1998), this genus has been found in symbiosis with ophiuroids, sponges, and cnidarians. They report another 10 genera and 20 species of symbiotic syllids, although no other syllid was found in a symbiotic relationship with any other terebellid examined during this study

Type locality: Key West , Florida, USA .

Distribution: Key West, Florida Strait, Aruba, Curaçao, Tobago. Intertidal to 205m.

Figures

FIGURE 8. Eupolymnia rullieri sp. nov., (Holotype ECOSUR 088): A. Thoracic region lateral view. B. Anterior end in ventral view. C. Anterior end in lateral view. D-F. Anterior end in dorsal view. G. Anterior thoracic region in lateral view. H. Branchiae: longer (right) from segment 2, shorter (left) from segment 4. I. Bilimbate notochaeta from segment 10. J. Uncinus from segment 5. K. Uncinus from segment 11. L. Uncinus from segment 25. Scale bars: A: 7.5mm; B,C: 1.6mm; D,E,F: 2.3mm; G: 1.9mm; H: 2.1mm; I: 0.05mm; J,K,L: 0.02mm.

FIGURE 9. Loimia bermudensis (Syntype YPM 1018): A. Anterior thoracic region in ventral view. B. Anterior end in ventral view. C. Anterior thoracic region in dorsal view. D. Anterior end in dorsal view. E. Unilimbate notochaetae from segment 11. F. Uncinus from segment 5. G. Uncinus from segment 11. H. Uncinus from segment 25. Scale bars: A,C: 4mm; B,D: 1.5mm; E: 0.05mm; F,G,H: 0.02mm.

FIGURE 10. Loimia minuta (Holotype AMNH 1992): A. Thorax in lateral view. B. Thorax in ventral view. C. Thorax in dorsal view. D,F. Anterior end in lateral view. E. Anterior end in ventral view. G. Bilimbate notochaetae from segments 18. H. Uncinus from segment 5. I. Uncinus from segment 11. J. Uncinus from segment 25. Scale bars: A,B,C,E,F: 1.3mm; D: 1.1mm; G: 0.05mm; H,I,J: 0.02mm.

FIGURE 11. Neoleprea sp. A., (ECOSUR TERE-16 15.II.1999): A. Anterior thoracic region in ventral view. B. Anterior thoracic region in dorsal view. C. Anterior end in lateral view. D. Branchiae from segment 2 (left) and 3 (right). E. Fascicle of notochaetae on notopodium from segment 10. F. Long chaeta from segment 10. G. Short notochaeta from segment 10. H. Uncini from segment 15. I. Double rows of uncini from segment 15. Scale bars: A,B: 0.7mm; C: 0.4mm; D: 0.15mm; E: 0.8mm, F,G: 0.3mm; H: 0.01mm; I: 0.04mm.

FIGURE 12. Neoleprea sp. 1., (ZMA V.Pol. 7571B): A. Thoracic region in ventral view. B. Anterior end in ventral view. C. Mid-thoracic region in lateral view. D. Fascicles of notochaetae on notopodium from segment 5. E. Long chaetae from segment 5. F. Short chaetae from segment 5. G. Uncini from segment 10. H. Double rows of uncini from mid-thoracic region. I. Pygidium. Scale bars: A: 1.1mm; B: 0.4mm; C: 0.3mm; D: 0.1mm; E,F: 0.05mm; G: 0.03mm; H: 0.03mm.

FIGURE 13. Pista cetrata (Holotype MCZ 834): A. Complete specimen in dorsal view. B. Anterior thoracic region in dorsal view. C. Anterior thoracic region in ventral view. D. Anterior end in dorsal view. Additional specimen: E. Anterior end in dorsal view. F. Anterior end in ventral view. G. Anterior end in lateral view. H. Bilimbate notochaeta from segment 10. I. Uncinus from segment 5. J. Uncinus from segment 6. K. Uncinus from segment 25. L. Pygidium from type specimen. M. Staining pattern of additional specimen in ventral view. N. Staining pattern of additional specimen in dorsal view. Scale bars: A: 4.6mm; B,C: 2.3mm; D: 0.8mm; E,F,G: 1.7mm; H: 0.05mm; I,J,K: 0.02mm; L: 1.3mm; M,N: 1.9mm.

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.