Oxydromus lanai, Rizzo, Alexandra E. & Salazar-Vallejo, Sergio I., 2014

Rizzo, Alexandra E. & Salazar-Vallejo, Sergio I., 2014, Hesionidae Grube, 1850 (Annelida: Polychaeta) from South-Southeastern Brazil, with descriptions of four new species, Zootaxa 3856 (2), pp. 267-291 : 281-285

Oxydromus lanai n. sp.

( Figs 5 , 6 )

Type material. Holotype, MZUSP 491, 23°47.414' S 45°21.800' W, Engenho d’Água Beach, São Paulo State, intertidal, 27.xi.1996. Paratypes (10): MZUSP 436 (5), 23°22'29.9" S 44°53'58.4" W, Porcos Pequenos Island, Ubatuba, SP, Sta. F2, intertidal, on algae Sargassum sp., 18.x.2001; MZUSP 439 (2), 23°05'04" S 45°18'50" W, Massaguaçú Island, Caraguatatuba, SP, Sta. F4, intertidal, on algae Dyctiota sp.; MZUSP 473 (1), 23°24'41" S 44°55'14" W, off Ubatuba, SP, Sta. 175I, subtidal, 7.8 m depth, 19.viii.2002; MZUSP 481 (1), 23°48'45" S 45°26'15" W, São Francisco Beach, SP, 20.v.2000; MZUSP 493 (1), 23°48'45" S 45°26'15" W, Araçá Beach, SP, intertidal, 18.ii.1997.

Additional material. 354 specimens: Baleia Beach, São Sebastião, SP, intertidal, on Sargassum sp. (23°46'27.8" S 45°40'31" W): MZUSP 405 (1), Sta. F9, 14.xi.2001; MZUSP 417 (2), Sta. F12, 14.xi.2001; MZUSP 420 (2), Sta. F10, 14.xi.2001; MZUSP 428 (1), Sta. F5, 14.ix.2001; MZUSP 435 (3), Sta. F14, 14.xi.2001; MZUSP 462 (1), Sta. S1T3Q52, 13.xii.2001; MZUSP 465 (1), Sta. ST2Q3, 12.xii.2001. Massaguaçú Beach, Caraguatatuba, SP, intertidal on Dictyota sp. or Sargassum sp. (23°35'04" S 45°18'50" W): MZUSP 396 (1), Sta. F5, 16.iii.2001; MZUSP 422 (1), Sta. F4, 27.ix.2001; MZUSP 423 (1), Sta. F15, 27.ix.2001; MZUSP 424 (1), Sta. F3, 16.iii.2001; MZUSP 426 (2), Sta. F6, 16.iii.2001; MZUSP 427 (1), Sta. F10, 27.ix.2001; MZUSP 438 (4), Sta. F2, 28.vii.2001; 16.iii.2001; MZUSP 441 (1), Sta. F9, 16.iii.2001; MZUSP 444 (2), Sta. F14, 16.iii.2001; MZUSP 447 (1), Sta. F10, 16.iii.2001; MZUSP 448 (2), Sta. F6, 27.ix.2001; MZUSP 451 (1), Sta. F7, 16.iii.2001; MZUSP 458 (2), Sta. F13, 16.iii.2001; MZUSP 460 (3), Sta. S1T3Q6, 19.ix.2001; MZUSP 469 (1), Sta. S1T3Q5, 19.ix.2001. Picinguaba Bay, Ubatuba, SP, intertidal, on Sargassum sp. (23°35'04" S 45°18'50" W): MZUSP 390 (4), Sta. F11, 18.x.2001; MZUSP 391 (2), Sta. F15, 18.x.2001; MZUSP 392 (2), Sta. F3, 18.x.2001; MZUSP 393 (1), Sta. F8, 18.x.2001; MZUSP 394 (5), Sta. F3, 08.vi.2001; MZUSP 399 (4), Sta. F2, 18.x.2001; MZUSP 400 (20), Sta. F5, 08.vi.2001; MZUSP 401 (9), Sta. F6, 08.vi.2001; MZUSP 402 (1), Sta. F6, 08.vi.2001; MZUSP 403 (2), Sta. F17, 18.x.2001; MZUSP 404 (8), Sta. F17, 18.x.2001; MZUSP 406 (18), Sta. F19, 18.x.2001; MZUSP 407 (3), Sta. F16, 08.vi.2001; MZUSP 408 (3), Sta. F19, 08.iv.2001; MZUSP 409 (10), Sta. F9, 08.vi.2001; MZUSP 410 (5), Sta. F15, 16.iii.2001; MZUSP 415 (2), Sta. F13, 18.x.2001; MZUSP 416 (13), Sta. F12, 08.vi.2001; MZUSP 419 (1), Sta. F14, 18.x.2001; MZUSP 432 (20), Sta. F14, 08.vi.2001; MZUSP 433 (1), Sta. F14, 08.vi.2001; MZUSP 434 (1), Sta. F14, 08.vi.2001; MZUSP 440 (2), Sta. F7, 18.x.2001; MZUSP 442 (16), Sta. F10, 08.vi.2001; MZUSP 446 (5), Sta. F9, 18.x.2001; MZUSP 450 (2), Sta. F14, 18.x.2001; MZUSP 453 (4), Sta. F18, 18.x.2001; MZUSP 454 (6), Sta. F6, 18.x.2001; MZUSP 455 (4), Sta. F3, 18.x.2001; MZUSP 457 (1), Sta. F11, 18.x.2001; MZUSP 459 (1), Sta. S1T1Q2, 17.x.2001; MZUSP 464 (1), Sta. S1T3Q13, 17.x.2001; MZUSP 466 (1), Sta. S1T1Q7, 09.ix.2001; MZUSP 468 (1), Sta. S1T1Q3, 17.x.2001; MZUSP 472 (1), Sta. S1T2Q19, 09.v.2001. Porcos Pequenos Island, Ubatuba, SP, intertidal on Sargassum sp. (23°22'29.9" S 44°53'58.4" W): MZUSP 398 (4), uba, SP, Sta. F7, 08.vi.2001; MZUSP 411 (7), Sta. F11, 08.vi.2001; MZUSP 412 (4), Sta. F20, 18.x.2001; MZUSP 413 (7), Sta. F13, 08.vi.2001; MZUSP 414 (8), Sta. F17, 08.vi.2001; MZUSP 418 (8), Sta. F4, 08.vi.2001; MZUSP 421 (5), Sta. F1, 08.vi.2001; MZUSP 425 (8), Sta. F4, 08.x.2001; MZUSP 429 (1), Sta. F13, 18.x.2001; MZUSP 430 (3), Sta. F16, 18.x.2001; MZUSP 431 (1), Sta. F2, on Dictyota sp., 16.iii.2001; MZUSP 437 (2), Sta. F19, 18.x.2001; MZUSP 443 (5), Sta. F20, 08.vi.2001; MZUSP 445 (4), Sta. F18, 08.vi.2001; MZUSP 449 (11), Sta. F2, 08.vi.2001; MZUSP 452 (6), Sta. F15, 08.vi.2001; MZUSP 456 (3), Sta. F1, 18.x.2001. Toque Toque Grande Beach, rocky shore, intertidal, São Sebastião, SP (23°50'03.8" S 45°30'38.4" W): MZUSP 470 (1), SP, Sta. S2T1Q7, 10.iv.2001; Sta. S2T1Q1, 10.iv.2001. Ubatuba, Caraguatatuba and São Sebastião Beaches, intertidal, rocky shore (23°22'26.6" S 44°50'20.3" W – 23°50'11.8" S 45°30'39.8" W): MZUSP 461 (3), Sta. S84NE, 08.vi.2001; MZUSP 476 (1), Sta. S39N1, 09.vi.2001; MZUSP 477 (1), Sta. S2T2Q15, 15.iii.2001; MZUSP 478 (3), Sta. S11N7, 16.iii.2001; MZUSP 480 (1), Sta. N46F1, 18.ix.2001; MZUSP 482 (1), Sta. N66S33N8, 16.iii.2001; MZUSP 483 (1), Sta. N53S1S11N3, 10.iv.2001; MZUSP 484 (1), Sta. S11N3, 16.iii.2001; MZUSP 485 (2), Sta. S33N2, 16.iii.2001; MZUSP 486 (1), Sta. S11N7, 16.iii.2001; MZUSP 487 (3), Sta. S87N1, 08.vi.2001; MZUSP 488 (2), Sta. N60Q9, 16.iii.2001; MZUSP 489 (2), Sta. N62Q14, 16.iii.2001; MZUSP 490 (1), Sta. S11N3, 16.iii.2001. Off São Paulo State, shallow subtidal (23°21'26.2" S 44°51'57.4" W –23°56'596" S 45°13'881" W): MZUSP 474 (1), Sta. 178I, 7.3 m, 19.viii.2002; MZUSP 475 (1), Sta. 148i, 30.1 m, 20.v.2002; MZUSP 494 (1), Sta. 6751I, 23°06.15' S 42°24.40' W, 93 m, 16.ii.1998; MZUSP 495 (1), Sta. 6769I, 22°02.87' S 40°05.93' W, 93 m, 02.iii.1998; MZUSP 496 (2), Sta. 6772I, 21°51.77' S 40°04.49' W, 110 m, 02.iii.1998.

Description. Complete specimens (n=50) 0.7–10.0 mm long (x = 4.33, sd= 2.47), 0.2–1.1 mm wide (x = 0.53, sd= 0.22), 8–45 chaetigers (x = 27.96, sd= 9.52). Coloration varying from yellowish to dark brown, without any pattern of pigmentation. Body subcylindrical.

Prostomium rounded to subtriangular, as long as wide ( Fig. 5 A). Palps biarticulate; palpophores short, stout, cylindrical, one-third as long as palpostyle; palpostyle conical, tapered. Lateral antennae conical, as long as palps. Median antenna conical, short, one-third as long as lateral ones, inserted frontally. Two pairs of large eyes, orange to reddish, lenticulate (rarely eyes without pigmentation); anterior eyes reniform shaped, posterior ones rounded ( Fig. 5 A). Nuchal organs distinct, on prostomial posterior margins, mid-dorsally separated. Six pairs of tentacular cirri, long, unequal; first two pairs in segment 1, third pair on segment 2. Tentacular cirri with cirrophores stout, cylindrical, short; cirrostyles long, tapered.

First chaetiger in segment 3; segments 3–5 (chaetigers 1–3) with notopodia more displaced dorsally than following chaetigers, reduced to cirrophores and cirrostyles, and supported by 1–3 notoaciculae, not protruding; notochaetae absent ( Fig. 6 B–C). From segments 6–8 (chaetigers 4–6), lateral notopodia shorter than neuropodia, with 1–4 notoaciculae x =2) slender, curved, not protruding ( Fig. 6 D–E); notochaetae one or two (x =1) long, slender furcated chaetae, shaft serrated below shorter tine; longer tine four times length of shorter; superior tine four times longer than inferior one ( Fig. 5 D). Neuropodia subtriangular, with 1–3, usually 1, stout neuroacicula, straight, not protruding. Neurochaetae falcigers, 4–10 supra-acicular, 8–16 sub-acicular, bidentate with short to long blades, serrate ( Fig. 5 F); medially placed chaetae with longer narrow blades ( Fig. 5 E).

Dorsal cirri with cirrostyles, weakly annulated; dorsal ones about three times longer than ventral ones. Ventral cirri smooth, about as long as parapodial lobes ( Fig. 6 B–E). Pygidium rounded; anal cirri long ( Fig. 5 C).

Pharynx muscular, coarse, with a subdistal ring, ciliated or fringed; papillae absent.

Oocytes about 50 µm in diameter, present from anterior to posterior region of the body. Juveniles or newly settled specimens with 8 chaetigers are 0.7 x 0.2 mm (length x width), have well-developed eyes, cephalic appendages, parapodial lobes and chaetae (MZUSP439, Fig. 5 A). One specimen, apparently epitokous, has large eyes and long abundant neurochaetae (MZUSP493, Fig. 5 B).

Remarks. Oxydromus lanai n. sp. resembles O. obscurus ( Verrill, 1873) as recorded by Uebelacker (1984), O. pugettensis as recorded by Hilbig (1994), and O. cf. guanicus by Hartman (1951). In the original description of O. obscurus, Verrill (1873) indicated four pairs of eyes with usually two minute additional eyespots. Upon the examination of type material (USNM 9695; 25 specimens), we observed that eyes are apparently absent or, if present, are colorless now. Further, it was not possible to see a mark where the eyes could have been, such as that observed in some of our eye-less specimens. Some cryptic specimens of O. lanai n. sp. found on algae have colorless eyes; however, the epitoke has very large reddish eyes. We found also two types of neurochaetae in O. obscure . Most were compound falcigers of variable lengths, but there was an additional simple neurochaeta, bidentate, marginally fringed, and positioned inferiorly in most parapodia. This was not mentioned in the original description. The pharynx of O. obscurus , when evaginated, is longer, and does not have fringe or papilla on its border, differing from O. lanai n. sp.

For Panamanian polychaetes, Fauchald & Reimer (1975: 83) and Fauchald (1977: 16) used the relative development of parapodial lobes to separate O. obscurus ( Verrill, 1873) from O. pugettensis ( Johnson, 1901) , with the former provided with a long postchaetal neuropodial lobe, and the latter with all pre- and postchaetal lobes of the same length. As for their distribution in Panama, O. obscurus was recorded from the Caribbean coast and O. pugettensis for the Pacific coast. However, type localities for both species are in temperate or cold-temperate waters, so both are questionable records for Panamanian beaches.

Oxydromus pugettensis has usually two, instead of one, furcate notochaeta, each being long and slender, with shorter tine serrated basally. Further, this species has been regarded as having a wide distribution along the Eastern Pacific Ocean, from Washington to Panama. An incomplete specimen from the Pacific coast of Panama, collected in Paitilla Beach, was identified as O. pugettensis by Fauchald (USNM 061648) and it resembles the Brazilian specimens in having one furcate notochaeta with serrated shaft. It will be necessary to examine more material from the Pacific coast of Panama to determine whether Oxydromus lanai n. sp. occurs there too.

Oxydromus cf. guanicus recorded from Southwestern Florida ( Hartman 1951:36) has smooth dorsal and ventral cirri, two notochaetae, and triangular neuropodial lobes. This could be an undescribed species, differing from O. guanicus ( Hoagland, 1919) in prostomial shape and relative development of the eyes. After the study of some specimens of O. guanicus (USNM 074062), we noticed that it differs from our specimens in several features: a) it has a characteristic pigmentation pattern—yellowish body with orange pigment on dorsal side of parapodial lobes and on the middle of prostomium; b) it is very large (a complete specimen measuring 32 mm length x 2.4 mm width, 80 chaetigers); c) its median antenna is less than one-third as long as lateral antennae; and d) its cirrophores are distally constricted producing a colorless ring, whereby the cirrostyle is inserted.

Etymology. The species is named after Paulo C. Lana, in recognition of his enthusiasm and leadership in Brazilian polychaete systematics, and for his many publications.

Distribution. Brazil, Rio de Janeiro and São Paulo States, in rocky shores and algae ( Sargassum sp. and Dictyota sp.), rarely on subtidal bottoms, 0– 110 m.

Figures

FIGURE 5. Oxydromus lanai new species. A. Holotype MZUSP 491, anterior region, dorsal view; B. Anterior region from an epitokous paratype MZUSP 439, dorsolateral view; C. Paratype MZUSP 436, posterior region, dorsal view; D. Furcate notochaetae, basally serrated near of shorter tine; E. Falciger bidentate with short and narrow blade; F. Falciger bidentate with short to long blade.

FIGURE 6. Oxydromus lanai new species. A. Paratype juvenile MZUSP 439 with 8 chaetigers, dorsal view; B. Paratype MZUSP 481, parapodium 1, posterior view; C. Same, parapodium 3, posterior view; D. Paratype MZUSP 493, parapodium 4, posterior view; E. Same, parapodium 9, anterior view.