Peresiella megapapilata Silva & Amaral 2022, sp. nov.

Peresiella megapapilata sp. nov.

(Fig. 4A–H; Table 2)

http://zoobak.org/ F872F67E-3DDF-449C-AADB-60FD761B337E

Material examined. Espírito Santo Basin: Holotype (ZUEC POL 20115) 19°49'6.3''S 39°36'8.4"W, 02 Dec 2011, subtidal, canyon, 24m, Stn. AMB6/CANWN4, 1 spec. Paratype 1 (ZUEC POL 20108) 19°49'8.9''S 39°36'8.9"W, 06 Jun 2013, subtidal, canyon, 181m, Stn. AMB12/CANWN4, 1 spec. Paratype 2 (ZUEC POL 20109) 19°46'1.4''S 39°30'34.8"W, 02 Dec 2011, subtidal, 121m, Stn. AMB6/D4, 1 spec. Paratype 3 (ZUEC POL 20110) 19°31'50.9''S 39°3'4.2"W, 06 Jun 2013, subtidal, canyon, 163m, Stn. AMB12/CAND4, 1 spec. Paratype 4 (ZUEC POL 20111) 19°46'32.1''S 39°30'4.1"W, 06 Jun 2013, deep-sea, 431m, Stn. AMB12/D5, 1 spec. Paratype 5 (ZUEC POL 20113) 19°46'1.4''S 39°30'34.8"W, 02 Dec 2011, subtidal, 121m, Stn. AMB6/D4, 1 spec. Paratype 6 (ZUEC POL 20114) 19°45'54''S 39°30'25.3"W, 06 Jun 2013, subtidal, 121m, Stn. AMB12/D4, 1 spec. Paratype 7 (ZUEC POL 20116) 19°31'50.9''S 39°3'4.2"W, 06 Jun 2013, deep-sea, canyon, 446m, Stn. AMB12/CAND4, 1 spec. Campos Basin: Paratype 8 (ZUEC POL 20117) 21°23'3.4''S 40°15'10.5''W, 06 Mar 2009, subtidal, 147m, Stn. HAB13/I5, on STUB, 1 spec. Paratype 9 (ZUEC POL 20118) 23°37'55.8''S 41°19'40.7''W, 03 Jul 2008, deep-sea, 390.6m, Stn. HAB7/A6, 1 spec.

Comparative material. Paratype Peresiella platyalia Green, 2002 (LACM-AHF POLY 2104), 9°00'N 98°03'E, 40m, 26 Apr 1996, Andaman Sea, Thailand. Holotype Peresiella spathulata Ewing, 1984 (USNM 81995) and 1 paratype (USNM 81996), 18°30.7'N 66°09.0'W, 257m, off Puerto Rico, Atlantic Ocean.

Description. Incomplete holotype 24.0 mm long, 0.33 mm wide for 42 chaetigers. Body slender, rounded; thorax almost the same width as abdomen; abdomen becoming thinner toward the posterior end. Whitish color in alcohol.

Table 2. Selected morphological characteristics of all described Peresiella species.

Prostomium conical, 1/2 of peristomium width, with a short palpode (Fig. 4A, C). Nuchal organs not everted; eyespots absent. Proboscis globular-shaped, densely papillated, with very coarse papillae (Fig. 4A). Peristomium long, 2x longer than wide and 1.5x longer than following chaetigers (Fig. 4A–C).

Thorax rounded, with uniform width, and 11 chaetigers. Chaetiger 1 uniramous. Capillaries on notopodia of chaetigers 1–3 and on neuropodia of chaetigers 2–3; remaining thoracic chaetigers with modified spatulate chaetae (Fig. 4E). Last half of peristomium, chaetiger 1, and first half of chaetiger 2 slightly tessellated laterally, with shallow lateral groove (Fig. 4A). Thoracic chaetigers straight, angled (90º edge) (Fig. 4B). Chaetigers 1–7 as long as wide, chaetigers 8–11 1.2x longer than wide (Fig. 4B, D); chaetae emerging from middle of segment up to chaetiger 8 and from third part of segment after chaetiger 9. Chaetigers 1–5 smooth, with shallow intersegmental groove; chaetigers 6–10 strongly biannulate, with deep and large intersegmental groove (Fig. 4B). Notochaetae inserted dorsally, neurochaetae inserted ventro-laterally. Modified spatulate chaetae short, inflated distally, with a smooth distal tip from where hair-like extension comes up, lacking hood (Fig. 4E). Lateral organs not visible. Transition between thorax and abdomen subtle, distinguished by appearance of hooks and by Methyl Green staining pattern (Fig. 4D).

Abdominal chaetigers with hooded hooks throughout; 2x longer than wide on anterior segments and 3x on posterior ones. Notopodial bundles inserted dorsally, both bundles very close, emerging directly from body wall, notopodial lobes not evident (Fig. 4B). Neuropodial bundles inserted ventro-laterally, emerging from thin and poorly developed lobes. Abdominal chaetae emerging from posterior part of segment, right before following chaetiger. Notopodia with five hooks per fascicle; neuropodia with seven hooks per fascicle. Notopodial hooded hooks with long and slightly curved main fang, surmounted by ca. 12 teeth arranged in four rows (3–3–3–3); narrow and smooth hood (Fig. 4F–G). Neuropodial hooded hooks with long and slightly curved main fang, surmounted by approximately 15 teeth arranged in five rows (3–3–3–3–3); narrow and smooth hood (Fig. 4H). Branchiae absent on observed chaetigers. Pygidium unknown.

Variation. Incomplete paratypes ranging from 2.5 to 25.0 long, 0.2 to 0.37 mm wide for 14 to 55 chaetigers.

Methyl Green staining pattern. Chaetigers two, three and 12 staining darker than the others; chaetigers 7–10 with small white circles (Fig. 4D). Ventral white line along the entire body. Lobes from abdominal segments staining with small dark dots around hooks (Fig. 4D).

Remarks. Two known Peresiella species (P. clymenoides and P. spathulata) have the same distribution of modified chaetae and hooded hooks on thorax as P. megapapilata sp. nov.; however, they differ from the new species in some respects. Peresiella clymenoides, for example, has a cephalic plate-like head, modified chaetae with long shaft, and hooded hooks with more than 20 teeth. Although P. spathulata is most similar to P. megapapilata sp. nov., it presents thoracic epithelium smooth (anterior thorax tessellated with a shallow lateral groove in P. megapapilata sp. nov.), modified spatulate chaetae with long shaft and hood (short, inflated distally, and lacking hood in P. megapapilata sp. nov.), hooded hooks with several teeth on the first row above the main fang (three teeth in P. megapapilata sp. nov.), and proboscis sparsely papillated (densely papillated, with very coarse papillae in P. megapapilata sp. nov.). The other species are quite different, P. platyalia presents hooded hooks on chaetiger 11 instead of modified spatulate chaetae, eyespot, and modified spatulate chaetae with a long shaft, brush-like distal tip, and hood; and P. acuminatobranchiata has modified spatulate chaetae on chaetigers four and five only and capillaries on remaining ones, branchiae, and a very pointed anterior end.

Etymology. This species was named after its very coarse proboscideal papillae, usually uncommon among capitellids species, especially the small ones. Mega means big, large, and papilata refers to papillae.

Habitat. From shallow water to deep-sea regions (121–446m), in soft-bottom.

Type locality. Espírito Santo Basin, Southwest Atlantic Ocean (8°40'55.3''S 38°55'41.48"W).

Distribution. Southwest Atlantic Ocean, Espírito Santo and Campos Basins (Brazil).