Exogone brasiliensis, Fukuda & Menezes-Moura & Guimarães & Ruta, 2019

Fukuda, Marcelo Veronesi, Menezes-Moura, Andrezza Ribeiro, Guimarães, Carmen Regina Parisotto & Ruta, Christine, 2019, A new species of Exogone Ørsted, 1845 (Annelida: Syllidae: Exogoninae) from Brazilian waters, Papéis Avulsos de Zoologia 59, pp. 1-8: 2-6

publication ID

http://doi.org/ 10.11606/1807-0205/2019.59.47

publication LSID

lsid:zoobank.org:pub:78DC07D8-6F18-47CE-A2AA-9BDBAD723A49

persistent identifier

http://treatment.plazi.org/id/386787A0-FFA5-0520-15B7-DD5BFA8F7C03

treatment provided by

Carolina

scientific name

Exogone brasiliensis
status

sp. nov.

Exogone brasiliensis   sp. nov.

( Figs. 1‑3 View Figure 1 View Figure 2 View Figure 3 )

Exogone (Exogone)   sp. 3 sensu Fukuda (2010): 144 -146, Fig. 42.

Exogone (Exogone)   sp. nov. C sensu Menezes (2012): 70 -73, Fig. 23.

Type material: Holotype ( MZUSP 3395 View Materials ): Campos Basin, State of Rio de Janeiro, offshore, 2246’54”S 41°03’33”W, 77 m, 02 Jul 2009. Paratypes: Campos Basin, State of Rio de Janeiro, offshore, 2142’53”S 40°10’15”W, 98 m: 16 specs ( ZUEC-POL 21353); 223’45”S 40°9’59”W, 76 m: 16 specs ( MNRJP 002205), 06 Jul 2009; 2246’54”S 41°3’33”W, 77 m: 18 specs ( MZUSP 3396 View Materials , paratype 1; MZUSP 3397 View Materials , 17 paratypes), 02 Jul 2009. State of Sergipe, offshore, 10°52’16”S 36°34’24”W – 50 m: 1 spec ( CZUFS-POL 00001, 1 paratype). GoogleMaps  

Additional material analysed: ‘REVIZEE’. State of Rio de Janeiro, 22°02’S 40°05’W, 93 m: 1 spec ( MZUSP 3461 View Materials ), 02 Mar 1998 GoogleMaps   ; 23°08’S 41°00’W, 100 m: 1 spec, 01 Mar 1998; 23°20’S 41°22’W, 110 m: 7 specs ( MZUSP 3462 View Materials ), 28 Feb 1998 GoogleMaps   ; 23°26’S 41°15’W, 145 m: 4 specs, 27 Feb 1998; 24°02’S 43°30’W, 147 m: 1 spec, 14 Feb 1998. State of Santa Catarina, 29°28’S 48°09’W, 210 m: 1 spec, 22 Mar 1998. ‘ Habitats’. State of Rio de Janeiro, Campos Basin , 21°09’9”S 40°16’7”W, 103 m: 26 specs ( MZUSP 3511 View Materials , 3512 View Materials ), 21 Jul 2009 GoogleMaps   ; 21°17’31.899”S 40°48’19.935”W, 24 m: 2 specs ( MZUSP 3405 View Materials ), 08 Mar 2009 GoogleMaps   ; 21°28’02.517”S 40°56’20.614”W, 16 m: 1 spec ( MZUSP 3401 View Materials ), 10 Mar 2009 GoogleMaps   ; 21°45’13”S 40°14’70”W, 67 m: 20 specs ( MZUSP 3407 View Materials , 3408 View Materials ), 14Mar 2009   ; 22°23’39”S 40°20’40”W, 153 m:5specs ( MZUSP 3429 View Materials ), 23 Fev 2009 GoogleMaps   ; 22°03’45”S 40°09’59”W, 75 m: 13 specs ( MZUSP 3433 View Materials , 3434 View Materials ), 25 Fev 2009 GoogleMaps   ; 22°46’54”S 41°03’33”W, 78 m: 39 specs ( MZUSP 3419 View Materials ), 22 Fev 2009 GoogleMaps   ; 23°11’30”S 41°00’47”W, 150 m:10 specs ( MZUSP 3414 View Materials ), 21 Fev 2009 GoogleMaps   ; 23°36’14”S 41°21’29”W, 142 m: 2 specs ( MZUSP 3411 View Materials ), 01 Mar 2009. ‘ Ambes’. State of Rio de Janeiro, Espírito Santo Basin , 19°33’20”S 38°42’52”W, 160 m: 2specs, 16 Jul 2013 GoogleMaps   ; 19°43’14”S 39°33’34”W, 50 m:6 specs, 14 Jul 2013; 21°03’31”S 40°22’59”W, 39 m: 3 specs, 11 Jul 2013; 20°34’53”S 40°06’27”W, 49 m: 43 specs, 12 Jul 2013; 20°35’23”S 39°55’01”W, 146 m: 2 specs ( MZUSP 3517 View Materials , 3518 View Materials ), 13Jul2013. ‘Petro/mar’. State of Alagoas, 10°18’02”S 36°07’04”W, 30 m: 1 spec ( CZUFS-POL 00006), Jun 2002, 1 spec ( CZUFS-POL 00007), Dez 2002, 1 spec ( CZUFS-POL 00008), Jun 2003. ‘Petro/mar’. State of Sergipe, 10°57’03”S 36°50’17”W, 30 m: 1 spec ( CZUFS-POL 00005), Jun 2002. ‘Marseal’. State of Sergipe, 10°52’32”S 36°49’20”W, 50 m GoogleMaps   :

6 specs ( CZUFS-POL 00002)   ; 11°10’00”S 36°52’17” W, 50 m: 1 spec ( CZUFS-POL 00003) GoogleMaps   ; 10°10’34”S 36°08’17”W, 50 m: 1 spec ( CZUFS-POL 00004) GoogleMaps   .

Comparative material analysed: Exogone aristata Hartmann-Schröder, 1982   , Australia, Western Australia, Beacon Island, NE entrance to Goss Passage (28°27’54”S 113°46’42”E), in coral substrate covered by algae, 24 m: 1 spec ( AM W26989 View Materials ), coll. P. Hutchings, 25 May 1994, det. G. San Martín, 2000; Beacon Island, off S end of Long Island (28°28’48”S 113°46’18”W), in dead coral substrate covered by coralline algae, 4-5 m: 3 specs ( AM W26990 View Materials ), coll. P. Hutchings, 25 May 1994, det. G. San Martín, 2000. Exogone dwisula Kudenov & Harris, 1995   , USA, California, Santa Maria Basin, between Purissima Point and Point Arguello (34°42’34”N 120°47’54”W), 100 m: 2 specs (paratypes, AM W22190 View Materials ) and 3 specs (paratypes, USNM 170913), coll. ‘DSR/V Diaphus’, 28 Jul 1984, det. L. Harris, 1995. Exogone heterosetosa McIntosh, 1885   , Australia, Western Australia, Long Island, Goss Passage (28°28’18”S 113°46’18”W), on dead coral covered with coralline algae and boring bivalves, 8 m: 10 specs ( AM W27057 View Materials ), coll. C. Bryce, 22 May 1994, det. G. San Martín, 2000. Exogone longicornis Westheide, 1974   , Ecuador, Galápagos Islands, Santa Cruz: 1 spec (holotype, ZMH P-13618), coll. and det. W. Westheide, 1972, 1974. Exogone mompasensis Martínez, Adarraga & San Martín, 2002   , Spain, Basque Country, Guipúzcoa, San Sebastián, Punta de Mompás (43°20’10”N 01°57’40”E): 12 specs (holotype, MNCN 16.01/8710; paratypes, MNCN 16.01/10118), coll. 08 Apr 1997. Exogone rolani   San Martín, 1991, USA, Florida, Port Everglades (26°07’42”N 80°04’48”W), 17 m: 2 specs (paratypes, USNM 101327).

Description: Body thin and elongate, longest specimen analysed ca. 6 mm long, 0,17 mm wide. Palps triangular, distally rounded, almost entirely fused, with conspicuous line of fusion and, sometimes, distal notch ( Figs. 1A View Figure 1 , 2A View Figure 2 ). Prostomium ovate, shorter than palps, with two pairs of nearly coalescent eyes in trapezoidal arrangement; anterior eyespots absent; antennae inserted close to each other, slightly anteriorly to anterior pair of eyes; median antenna elongated, subdistally thin, almost seven times as long as lateral antennae;lateral antennae digitiform to ovate ( Figs. 1A View Figure 1 , 2A View Figure 2 ). Peristomium shorter than following chaetigers, sometimes covering posterior part of prostomium, including posterior pair of eyes; peristomial cirri ovate,slightly shorter than lateral antennae ( Figs.1A View Figure 1 , 2A View Figure 2 ). Dorsal cirri small, rounded to ovate, shorter than peristomial cirri, present on all chaetigers ( Figs. 1A View Figure 1 , 2A View Figure 2 ); ventral cirri small, rounded to ovate, with same size as dorsal ones, or slightly smaller ( Fig. 2B View Figure 2 ). Parapodia 1-5 with ca. 10 falcigers each; shafts of falcigers subdistally spinulated throughout; on chaetigers 1 and 2, shafts of the two dorsalmost falcigers modified, subdistally inflated, with acute tip ( Fig. 1B View Figure 1 ); blades of anteriormost falcigers modified, 1-3 dorsalmost sometimes spinulated with short spines, distally bidentated ( Figs. 1C View Figure 1 , 3H View Figure 3 ), remaining anterior body falcigers with blades progressively longer ventralwards, smooth, with subdistal tooth conspicuously longer, distal tooth reduced ( Figs. 1D View Figure 1 , 3 View Figure 3 A-B, G-H); blades 6-12 µm long, ventralmost ones approximately twice as long as dorsalmost ones. From proventricle level onwards, parapodia with 1 spiniger-like chaeta and 3-4 falcigers each; spiniger-like chaetae with subdistally enlarged shafts, with coarse spinulation forming ridges in some chaetae( Fig.3D View Figure 3 );blades of spiniger-like chaetae relatively short, ca. 20 µm long on midbody ( Figs. 1E View Figure 1 , 3 View Figure 3 C-D), 16- 12 µm on posterior body ( Figs. 1F View Figure 1 , 3D View Figure 3 ), unidentate, with short basal spinulation; blades of falcigers spinulated, bidentate, with subdistal tooth larger than distal one and subtle dorso-ventral gradation in length, blades ca. 10- 8 µm long on midbody, slightly shorter on posteri- or body ( Figs. 1 View Figure 1 E-F, 3C, E-F). Dorsal simple chaetae on anterior body slightly sigmoid, subdistally spinulated, with acute tip ( Fig. 1G View Figure 1 ), protruding for short extension from parapodial lobes; from midbody onwards, dorsal simple chaetae nearly straight and subdistally enlarged on one side, with acute, rounded tip ( Figs. 1H View Figure 1 , 3 View Figure 3 C-D); ventral simple chaetae only present on posteriormost chaetigers, sigmoid, bidentate, with subdistal tooth larger than distal one ( Figs. 1I View Figure 1 , 3I View Figure 3 ). Anterior body parapodia with 2 aciculae each, distally inflated, hollow ( Fig. 1J View Figure 1 ); from midbody onwards, parapodia with only 1 acicula each, similar to anterior body aciculae, but progressively thicker towards posterior body ( Fig. 1K View Figure 1 ). Pygidium with a pair of long anal cirri, slightly longer than median antenna ( Fig. 2E View Figure 2 ). Pharynx extending through 5-6 segments, with opening densely surrounded by cilia and conical tooth in anterior ⅓ of its length ( Figs.1A View Figure 1 , 2 View Figure 2 B-D); proventricle extending for 5-6 segments, with ca. 40 rows of muscle-cells ( Fig. 1A View Figure 1 ).

Remarks: Exogone brasiliensis   sp. nov. is characterized by having the two dorsalmost falcigers modified on chaetiger 1 and 2, with shafts subdistally inflated, with acute tip; falcigers of chaetigers 1-5 modified, ventralmost blades smooth, with subdistal tooth distinctly larg- er than the distal one, conspicuously longer than those from chaetiger 6 onwards; dorsal simple chaetae, from midbody onwards, subdistally enlarged on one side, with acute, rounded tip; and proventricle extending for 5-6 segments, with ca. 40 rows of muscle-cells.

Exogone brasiliensis   sp. nov. belongs to a group of species of the genus that presents falciger blades with subdistal tooth larger than the distal one and elongat- ed median antenna, reaching beyond tip of palps. This group also encompasses Exogone aristata   , Exogone heterosetosa   , Exogone longiantennata Hartmann-Schröder, 1979   , Exogone longicornis   , Exogone mompasensis   and Exogone rostrata Naville, 1933   . However, E. aristata   differs from E.brasiliensis   sp. nov. by the presence of aristae (large distally directed spines, usually extending beyond the tip of the chaeta) on falciger blades and on dorsal and ventral simple chaetae; E.longiantennata   has no eyes neither dorsal cirri on chaetiger 2; both E.longicornis   and E.rostrata   present shafts of spiniger-like chaetae of chaetiger 1 with a subdistal thickening forming a triangular process, which is absent in E. brasiliensis   sp. nov. Finally, E. heterosetosa   and E. mompasensis   differ from E. brasiliensis   sp. nov. by having spiniger-like chaetae modified, with shafts distally inflated and strongly spinulated, and relatively short, triangular blades.

Exogone dwisula   and Exogone naidina   also have compound chaetae of the first chaetigers with modified blades. However, different from Exogone brasiliensis   sp. nov., modified falciger blades in both these species present no denticle corresponding to the distal tooth, and they show a pronounced spine at the base of the blades, sometimes distally directed, giving the blades the appearance of a “can opener” ( Kudenov & Harris, 1995; San Martín, 2003, 2005). In addition, both E. dwisula   and E.naidina   have dorsal simple chaetae on posterior body sigmoid, subdistally inflated and spinulated, with acute tip, while E.brasiliensis   sp. nov. presents dorsal simple chaetae straighter than usual for the genus, subdistally swollen only on one side, distally rounded.

Perhaps the most similar species to Exogone brasiliensis   sp. nov. is Exogone rolani   , by having enlarged median antenna, dorsal cirri on all chaetigers, falcigers with subdistal tooth larger than distal one, and shafts of falcigers on chaetigers 1-5 modified, with large, pointed, oblique tip ( Paresque et al., 2014). However, E. rolani   differs from E. brasiliensis   sp. nov. by having spiniger-like chaetae on all chaetigers and with longer blades than those of E. brasiliensis   sp. nov., up to 25 µm long, while spiniger-like chaetae are absent from the first 5 chaetigers of E. brasiliensis   sp. nov., and the longer blades are up to 20 µm long. Furthermore, E.rolani   presents dorsal simple chaetae with a more common morphology to the genus, sigmoid, subdistally spinulated, with acute tip (see Paresque et al., 2014, figs. 7C, G, K), while, from midbody onwards, dorsal simple chaetae of E. brasiliensis   sp. nov. are quite unique, nearly straight and subdistally swollen on one side only, distally rounded. Finally, despite extending for a similar number of chaetigers, the proventricle in E. brasiliensis   sp. nov. presents more muscle cell rows than that of E. rolani   (ca. 40 × ca. 29).

Etymology: This species was named brasiliensis   because the type locality is in Brazil and the species presents a large distribution along the coast.

Distribution: Atlantic Ocean: Brazil (Alagoas, Sergipe, Espírito Santo, Rio de Janeiro and Santa Catarina).

AM

Australian Museum

USNM

Smithsonian Institution, National Museum of Natural History

ZMH

Zoologisches Museum Hamburg

MNCN

Museo Nacional de Ciencias Naturales

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Phyllodocida

Family

Syllidae

Genus

Exogone

Loc

Exogone brasiliensis

Fukuda, Marcelo Veronesi, Menezes-Moura, Andrezza Ribeiro, Guimarães, Carmen Regina Parisotto & Ruta, Christine 2019
2019
Loc

Exogone (Exogone)

Menezes, A. R. 2012: 70
2012
Loc

Exogone (Exogone)

Fukuda, M. V. 2010: 144
2010