Scyphoproctus robustus, Silva & Amaral, 2019

Silva, Camila Fernanda Da & Amaral, Antonia Cecilia Zacagnini, 2019, Scyphoproctus Gravier, 1904 (Annelida, Capitellidae): description of three new species and relocation of Heteromastides Augener, 1914 in Scyphoproctus, Zootaxa 4560 (1), pp. 95-120: 114-118

publication ID

https://doi.org/10.11646/zootaxa.4560.1.5

publication LSID

lsid:zoobank.org:pub:33C0A0BC-5124-4C75-92E1-1AB5862D04D4

persistent identifier

http://treatment.plazi.org/id/6E3187A3-FFC0-3D3D-6DA4-FF47FB264BCF

treatment provided by

Plazi

scientific name

Scyphoproctus robustus
status

sp. nov.

Scyphoproctus robustus   sp. nov.

( Figures 11 View FIGURE 11 ̄13)

Type series. Holotype ( ZUEC POL 20522 View Materials ): state of São Paulo, São Sebastião, São Sebastião Channel (23°44'54"S, 45°24'34"W): coll. 0 4 Oct 1995; soft-bottom; intertidal; Stn. 445A; 1 spec GoogleMaps   . Paratypes: state of São Paulo, São Sebastião, São Francisco Beach (23°44'54"S, 45°24'34"W): paratypes 1̄3 ( ZUEC POL 20510 View Materials ): coll. 26 Jun 2013; sandy beach; intertidal; Stn. 45; 3 specs GoogleMaps   . Paratypes 4̄10 ( ZUEC POL 20513 View Materials ): coll. 23 Jun 2013; sandy beach; intertidal; Stn. 47; 7 specs. State of São Paulo, São Sebastião, Araçá Bay (23°48'S, 45°24'W): paratype 11 ( ZUEC POL 20506 View Materials ): coll. 15 Jun 2011; soft-bottom; intertidal; Stn. 22(1)A; 1 spec. State of Paraíba, Cabo Branco Beach (7°08'S, 34°47'W): paratypes 12 and 13 ( ZUEC POL 20519 View Materials ): coll. 0 1 Feb 2010; in rhodoliths; intertidal; 2 specs GoogleMaps   .

Additional material examined. State of São Paulo, São Sebastião, Engenho D’Água Beach GoogleMaps   (23°47'49"S, 45°21'56"W). (ZUEC POL 1779): coll. 25 Nov 1996; soft-bottom; intertidal; Stn. 2807B; 1 spec. (ZUEC POL 1854): coll. 20 May 1996; soft-bottom; intertidal; Stn. 1883B; 1 spec. (ZUEC POL 1855): coll. 20 May 1996; softbottom; intertidal; Stn. 1881A; 2 specs. (ZUEC POL 1935): coll. 0 8 Apr 1997; soft-bottom; intertidal; Stn. 3199B; 2 specs. (ZUEC POL 1936): coll. 0 8 Apr 1996; soft-bottom; intertidal; Stn. 3196A; 6 specs. (ZUEC POL 1954): coll. 0 2 Jul 1996; soft-bottom; intertidal; Stn. 3199B; 1 spec. State of São Paulo, São Sebastião, São Francisco Beach GoogleMaps   (23°44'54"S, 45°24'34"W). (ZUEC POL 20511 View Materials ): coll. 26 Jun 2013; sandy beach; intertidal; Stn. 72; 1 spec. (ZUEC POL 20512 View Materials ): coll. 26 Jun 2013; sandy beach; intertidal; Stn. 71; 9 specs. (ZUEC POL 20514 View Materials ): coll. 11 Apr 2013; sandy beach; intertidal; Stn. 20P; 15 specs. (ZUEC POL 20515 View Materials ): coll. 11 Apr 2013; Stn. 5G; 2 specs. (ZUEC POL 20516 View Materials ): coll. 26 Jun 2013; sandy beach; intertidal; Stn. 43; 7 specs. (ZUEC POL 20521 View Materials ): coll. 0 4 Dec 1995; sandy beach; intertidal; Stn. 445A; 3 specs. State of São Paulo, São Sebastião, Araçá Bay GoogleMaps   (23°48'S, 45°24'W). (ZUEC POL 20504 View Materials ): coll. 14 Jun 2011; soft-bottom; intertidal; Stn. 10(3)B; 1 spec. (ZUEC POL 20505 View Materials ): coll. 10 Oct 2013; shallow sublittoral; 8.6 m deep; Stn. 29(1)Mc; 1 spec. State of São Paulo, Caraguatatuba, Camaroeiro Beach GoogleMaps   (23°37'38"S, 45°23'50"W). (ZUEC POL 20520 View Materials ): coll. 25 May 2006; in mussel bed; intertidal; Stn. 16A; 1 spec. State of São Paulo, Caraguatatuba, Enseada Beach GoogleMaps   (23°43'40"S, 45°25'10"W). (ZUEC POL 20517 View Materials ): coll. 11 Apr 2013; soft-bottom; intertidal; Stn. 47P; 6 specs. State of Espírito Santo, Espírito Santo Basin—continental shelf GoogleMaps   . (ZUEC POL 20507 View Materials ): (18°40'55,3''S, 38°55'41,48"W); coll. 17 Jan 2012; sublittoral; 44m deep; Stn. AMB 7/G03; 2 specs. (ZUEC POL 20508 View Materials ): (21°2'45,81''S, 40°32'29,21"W); coll. 22 Jan 2012; sublittoral; 20m deep; Stn. AMB 7/A01; 1 spec. (ZUEC POL 20509 View Materials ): (18°40'55,3''S, 38°55'41,48"W); coll. 0 2 Dec 2011; sublittoral; 34m deep; Stn. AMB 7/E02; 1 spec. State of Paraíba, Cabo Branco Beach GoogleMaps   (7°08'S, 34°47'W). (ZUEC POL 20518 View Materials ): coll. 0 8 Feb 2009; in rhodoliths; intertidal; 5 specs.

Description. Complete holotype 9.5 mm long, 0.8 mm wide for 53 chaetigers. Incomplete specimens 0.30–1.5 mm wide for 32–66 chaetigers. Body robust; similar width between thorax and abdomen; slightly narrowing toward pygidium. Whitish color in alcohol.

Prostomium robust, 2x longer than wide, rounded on anterior end, usually withdrawn into peristomium ( Figs 11A View FIGURE 11 ; 12A View FIGURE 12 ; 13A View FIGURE 13 ); nuchal organs not observed; eyespots as a pair of oval postero-lateral densely pigmented areas. Proboscis globular-shaped, with several large papillae ( Figs 11B View FIGURE 11 ; 12C View FIGURE 12 ). Peristomium 1.5x longer than thoracic segments ( Figs 11A View FIGURE 11 ; 12A View FIGURE 12 ; 13A View FIGURE 13 ). Complete inter-segmental groove between peristomium and achaetous segment ( Figs 11A View FIGURE 11 ; 12A View FIGURE 12 ). Peristomium and achaetous segment weakly rugose ( Fig. 11A View FIGURE 11 ).

Thorax with 12 segments, including peristomium, one additional achaetous segment and 10 chaetigers ( Figs 11A View FIGURE 11 ; 12A View FIGURE 12 ; 13A View FIGURE 13 ). Bilimbate capillaries in notopodia and neuropodia of chaetigers 1–10. Thorax with chaetigers distinctly biannulate, more evident after chaetigers 5–6 ( Figs 12A View FIGURE 12 ; 13A View FIGURE 13 ); moderate depth of inter-segmental grooves between chaetigers. First chaetiger biramous. Notopodial lobes inserted dorso-laterally and neuropodial lobes laterally. Lateral organs present since the achaetous segment and throughout thorax, between noto- and neuropodia, closer to notopodia ( Figs 11A View FIGURE 11 ; 12D View FIGURE 12 ; 13A View FIGURE 13 ). Transition between thorax and abdomen inconspicuous, marked only by change of chaetae and methyl green staining pattern ( Figs 11A View FIGURE 11 ; 12A View FIGURE 12 ̄B).

Abdominal chaetigers without capillaries. Abdominal noto- and neuropodia with moderately developed tori pads separated by same distance throughout ( Fig. 12E, H View FIGURE 12 ). First notopodial chaetigers with 9 hooks per fascicle, reducing in number toward posterior end; first neuropodial chaetigers with 15 hooks per fascicle, increasing in number toward mid-abdomen, and then reducing in number toward posterior end. Notopodial hooks (with SEM) with a narrow main fang, finger-shaped, right angle with shaft, surmounted by 12 teeth arranged in four rows (3–3–

3–3); large, thin and smooth hood ( Fig. 13B View FIGURE 13 ). Neuropodial hooks (with SEM) with a large and robust main fang, triangular, right angle with shaft, surmounted by 22 teeth arranged in three rows (4–6–12); large and thin hood with a serrate margin ( Fig. 13C View FIGURE 13 ).

Modified pre-pygidial segments absent, all preceding segments with noto- and neuropodial hooks. Anal plaque flat, oval shaped, nine sets of acicular spines protruding from plaque margin (8,5,3,3,2,2,2,2,1, each side); small anus near the inferior margin, not reaching plaque margin; two short thin fused cirri (one-third plaque length), without median membrane ( Figs 11C View FIGURE 11 ̄D; 12F̄G).

Variation. Paratypes with 12–14 segments, including the peristomium, one additional achaetous segment and 10–12 chaetigers. Adult specimens with bilimbate capillaries in noto- and neuropodia of chaetigers 1–10/12. Number of hooks of the first abdominal lobe size dependent, notopodium ranging from 3 to 20 and neuropodium from 6 to 20 hooks. set of Acicular spines from the plaque margin size dependent, smaller specimens with 3,3,2,2,1,1,1,1,1 spines each side.

Methyl green staining pattern. Thoracic segments staining uniformly darker than the abdomen; final thoracic chaetigers with a fine dark band on the inter- and intra-segmental grooves; abdominal chaetigers staining uniformly light green ( Fig. 12B View FIGURE 12 ).

Remarks. Scyphoproctus robustus   sp. nov. belongs to a group of species with the set of acicular spines positioned marginally on the plaque, either protruding from the edge or embedded, which includes Scyphoproctus djiboutiensis   , S. fasciculatus   , S. glabrus   , S. guadalupensis   , S. lumenalis   , S. oculatus   , S. ornatus   , S. platyproctus   and S. variabilis   .

Scyphoproctus glabrus   and S. guadalupensis   are different from S. robustus   sp. nov. in having two pre-pygidial segments with notopodia bearing acicular spines, while Scyphoproctus robustus   sp. nov. has hooded hooks on both noto- and neuropodia, therefore lacking modified pre-pygidial segments. The differences between Scyphoproctus robustus   sp. nov. and S. glabrus   are also related to the number of sets of acicular spines of the anal plaque, which is nine in the former and fourteen in the latter, and the features of the abdominal hooded hooks. Scyphoproctus glabrus   has similar noto- and neuropodial hooded hooks, with 10–15 teeth above main fang arranged in three rows, while Scyphoproctus robustus   sp. nov. has notopodial hooded hooks with 12 teeth arranged in four rows and neuropodial hooded hooks with 22 teeth arranged in three rows.

Scyphoproctus fasciculatus   and S. ornatus   differ from Scyphoproctus robustus   sp. nov. by the number of sets of acicular spines of the anal plaque, number of acicular spines, length of anus and features of the cirri. Scyphoproctus fasciculatus   presents an anal plaque with three sets of acicular spines with two spines each, anus with moderate length and cirri longer than the plaque with a median membrane. Scyphoproctus ornatus   presents an anal plaque with 10 sets of acicular spines with several spines each (16,11,6,4,3,4,3,1,1,1) and large anus.

Scyphoproctus oculatus   , S. platyproctus   and S. variabilis   differ from Scyphoproctus robustus   sp. nov. by the presence of pre-pygidial segments with acicular spines, different from the latter species, which has none. Scyphoproctus oculatus   has 2–6, S. platyproctus   has 4–7 and S. variabilis   has two. Although S. lumenalis   also lacks pre-pygidial segments with acicular spines, it differs from Scyphoproctus robustus   sp. nov. because the spines of the plaque are embedded and by the presence of two long cirri (longer than plaque length) with a median membrane, in contrast to Scyphoproctus robustus   sp. nov., which has protruding spines, and short cirri without a median membrane.

Although Scyphoproctus djiboutiensis   also has a thoracic region with 14 segments (12 chaetigers) and short cirri without a median membrane, the species differs from Scyphoproctus robustus   sp. nov. by the number of sets of acicular spines, which is 11, lack of eyespots, proboscis without papillae, smooth thorax, absence of lateral organs and similar noto- and neuropodial hooded hooks.

Etymology. Latin word that means “strong”. This species was named after its width, since it is one of the largest species of the genus.

Habitat. From intertidal to sublittoral regions (0–44m); in soft-bottom, mussel beds and rhodoliths.

Type locality. São Francisco Beach , São Paulo   , Brazil, 23°44'54"S, 45°24'34"W (South Atlantic Ocean). Distribution. South Atlantic Ocean : Brazil (states of Espírito Santo, Paraíba and São Paulo) GoogleMaps   .

ZUEC

Museu de Zoologia da Universidade Estadual de Campinas