Petta alissoni,

Nogueira, João Miguel De Matos, Ribeiro, William M. G., Carrerette, Orlemir & Hutchings, Pat, 2019, Pectinariidae (Annelida, Terebelliformia) from off southeastern Brazil, southwestern Atlantic, Zootaxa 4571 (4), pp. 489-509: 502-506

publication ID

https://doi.org/10.11646/zootaxa.4571.4.3

publication LSID

lsid:zoobank.org:pub:62AE5784-A6E5-479B-835A-32B5F9828FC3

persistent identifier

http://treatment.plazi.org/id/9111C272-A068-3D05-DAB2-FE184877FF55

treatment provided by

Plazi

scientific name

Petta alissoni
status

n. sp.

Petta alissoni  n. sp.

( Figs 8–12View FIGURE 8View FIGURE 9View FIGURE 10View FIGURE 11View FIGURE 12, Table 2)

Material examined. Holotype ( ZUEC Pol 7891): coll. state of São Paulo, 24°21'S 44°10'W, 10 Jan 1998, 258 m.GoogleMaps  Paratype 1 ( ZUEC Pol 7880): coll. state of Rio de Janeiro, 23°09'36”S 40°57'00”W, 01 Mar 1998, 257 m.GoogleMaps  Paratypes 2–5 ( ZUEC Pol 7882 and 21341–21343): coll. state of Rio de Janeiro, 23°36'30”S 42°10'00”W, 16 Feb 1998, 187 m; paratype 2 ( ZUEC Pol 21343) mounted on SEM stub, paratype 5 ( ZUEC Pol 21342) dissected, some notochaetae and uncini mounted on microscope slideGoogleMaps  . Paratype 6 ( ZUEC Pol 7892): coll. state of São Paulo, 24°07'36”S 45°52'00”W, 09 Jan 1998, 147 m.GoogleMaps  Paratype 7 ( ZUEC Pol 7890): coll. state of São Paulo, 24°07'18”S 44°42'00”W, 09 Jan 1998, 101 m. Morphological variation within the type series is shown in Table 2GoogleMaps  .

Comparative material examined. Petta pusilla Malmgren  , 1 866, NRM 104108: coll. Sweden, Bohuslän, Koster area, Kostergrund, 3 specs in excellent state of preservation.

Description. Tubes not studied, as all specimens examined lacked tubes. Conical body, 5–18 mm long and 1– 2 mm wide, pale creamy in color. Operculum with smooth marginal lobe low all around; 10–12 pairs of long golden paleae, distally tapering to blunt tips, slightly curved dorsalwards ( Figs 8View FIGURE 8 A–C, E–G; 9A; 10A, B; 11A; 12A; Table 2). Cephalic veil completely free from operculum, with few short, pointed buccal tentacles; distal margin of cephalic veil smooth, except for medial triangular cirrus, distally entire or bifid ( Figs 8View FIGURE 8 A–C; 9A; 10B); cephalic veil terminating by rounded flaring lobe at each side, each ending by spherical papilla. Tentacular cirri of segments 1 and 2 of similar length, both thin and elongate, distally blunt; tentacular cirri of segment 1 ventrally aligned to those of segment 2 ( Figs 8View FIGURE 8 A–C, E–G; 9A, C; 10A, B). Segments 2–6 distinctly raised ventrally, as ventral crests; first crest, on segment 2, with pair of low ventral lobes interrupted mid-ventrally, each side reaching mid-ventral line, with 5–7 marginal cirri; segment 3 with ventrolateral crests interrupted mid-ventrally by pair of large spherical papillae ( Figs 8View FIGURE 8 A–C, E, G; 9A–C; 10B, C; Table 2). Two pairs of small pectinate stalked branchiae, on segments 3 and 4, each pair consisting of loose, flat and smooth rounded lamellae, almost circular, first pair slightly larger, inserted laterally, second pair inserted dorso-laterally ( Figs 8View FIGURE 8 E–G; 9C; 10A, E). Notopodia beginning on segment 5, extending until segment 21, first 3 pairs shorter; neuropodia beginning on segment 8, extending until segment 21; last segment before scaphe with biramous parapodia ( Fig. 12HView FIGURE 12). Notochaetae of two types, those of anterior row with narrow limbation from base, terminating by serrated alimbate blade, much wider at base, triangular, with smooth edge and coarse striations on sides, edge serrated from immediately after base of blade; chaetae of posterior row narrowly-winged throughout ( Figs 10DView FIGURE 10; 11View FIGURE 11 B–C; 12B–E, H). Neurochaetae as avicular uncini, with clearly defined main fang, with 2–3 transverse rows of progressively shorter secondary teeth on top, short triangular heel, slightly curved base and rounded basal peg, composed of many densely packed denticles as seen under SEM ( Figs 11DView FIGURE 11; 12F, GView FIGURE 12). Scaphe consisting on five fused posterior segments, not clearly separated from segment 21; scaphe oval in shape, flattened and arched ventrally, lateral margins with 6 pairs of lamellae, anal flaps distinctly short, shorter than lateral papillae, with long anal cirrus inbetween dorsally ( Figs 8DView FIGURE 8, H–J; 9D, E; 10A, F); 5–8 pairs of brown, dorso-lateral scaphal hooks distally blunt, slightly arched posteriorwards ( Figs 10FView FIGURE 10; 11EView FIGURE 11; 12View FIGURE 12 H–J; Table 2).

Variation. Intraspecific variation among the specimens of the type series is given in Table 2. Observed variation in the numbers of pairs of paleae, scaphal hooks and cirri on ventral lobes of segment 2 is size-related ( Table 2).

Remarks. Members of P. pusilla  differ from specimens of P. alissoni  n. sp. in having distally trifid medial extension of cephalic veil, fewer pairs of cirri on lobes of segment 2, with wider mid-ventral gap, larger midventral lobes on segment 3, and distinctly shorter scaphal medial cirrus, about as long as lateral papillae. Members of P. alissoni  n. sp., in contrast, have distally entire or bifid medial extension of cephalic veil (paratype 7 with bifid extension, entire in all other specimens) and scaphal cirrus about 5 times as long as lateral papillae.

Members of P. pellucida ( Ehlers, 1887)  differ from individuals of P. alissoni  n. sp. in having distally entire and blunt medial extension of cephalic veil, lobes of segment 2 with pair of ventralmost cirri distinctly longer than other cirri, longer mid-ventral lobes on segment 3, cylindrical and distally rounded. Among members of P. alissoni  n. sp., the medial extension of the cephalic veil is distally pointed, cirri of lobes of segment 2 are all of even length, and the mid-ventral lobes of segment 3 are spherical.

Petta assimilis McIntosh, 1885  was described based on material from the Kerguelen Islands, Indian Ocean, and the type material is lost, according to Alexander Muir (personal communication). According to the original description, the holotype of P. assimilis  differed from specimens of P. alissoni  n. sp. in having triangular, distally entire cephalic veil; lobes of segment 2 with 4–5 pairs of cirri, the ventralmost pair distinctly shorter; entire lobe on segment 3, extending across ventral surface of segment without mid-ventral gap, distally cirrate throughout; scaphe with distinctly larger anal flaps, fused to each other in a foliaceous process, with minute terminal cirrus; and notochaetae without specialization at base of blade. In contrast, members of P. alissoni  n. sp. have an almost circular cephalic veil, with entire or bifid medial extension; 5–7 pairs of cirri on lobes of segment 2, all of similar length; smooth ventrolateral crests on segment 3, with pair of mid-ventral spherical lobes; scaphe with minute anal flaps, rounded, and distinctly longer terminal cirrus; and their notochaetae have a foliaceous process at base of blade.

Members of P. tenuis Caullery, 1944  , according to the original description, have ventro-lateral lobes of segment 2 with 4 pairs of triangular cirri, U-shaped ventral lobe on segment 3, and uncini with 3 teeth only, main fang and 2 secondary teeth. In contrast, members of P. alissoni  n. sp. have 5–7 pairs of cirri on lobes of segment 2, segment 3 without a ventral lobe, with a pair of spherical papillae instead, and uncini with more secondary teeth, main fang and 2–3 transverse rows of progressively shorter secondary teeth.

Type locality. The holotype comes from off the state of São Paulo, southeastern Brazil, southwestern Atlantic. The type series includes material from the northern coast of São Paulo and southern coast of Rio de Janeiro. Etymology. This species is dedicated to Alisson Ricardo da Silva for his friendship with JMMN.

ZUEC

Museu de Zoologia da Universidade Estadual de Campinas

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Terebellida

Family

Pectinariidae

Genus

Petta

Loc

Petta alissoni

Nogueira, João Miguel De Matos, Ribeiro, William M. G., Carrerette, Orlemir & Hutchings, Pat 2019
2019
Loc

P. alissoni

Nogueira & Ribeiro & Carrerette & Hutchings 2019
2019
Loc

P. alissoni

Nogueira & Ribeiro & Carrerette & Hutchings 2019
2019
Loc

P. alissoni

Nogueira & Ribeiro & Carrerette & Hutchings 2019
2019
Loc

P. tenuis

Caullery 1944
1944
Loc

Petta assimilis

McIntosh 1885
1885
Loc

P. assimilis

McIntosh 1885
1885