Scolelepis ( Polychaeta : Spionidae ) from the Brazilian coast with a diagnosis of the genus

Five species of Scolelepis have been reported for the Brazilian coast. This study raises this number, with two new records: S. acuta Treadwell, 1914, originally from Eastern Pacific, and Scolelepis andradei Delgado-Blas, Diaz & Linero-Arana, 2009, from the Caribbean Sea. Furthermore, two species were found to have an expanded geographic range along the Brazilian coast: Scolelepis lighti Delgado-Blas, 2006 and Scolelepis goodbodyi Jones, 1962.

ZOOLOGIA 29 (4): 385-393, August, 2012 Before examination, the worms were anesthetized with isotonic magnesium chloride for 20 minutes; while some were fixed in 10% formalin and transferred to 70% ethanol, others were preserved directly in 92% ethanol.A total of 804 specimens were examined under a ZEISS Stemi stereomicroscope.
Illustrations of the external morphology were prepared under a camera lucida coupled to a stereomicroscope and optical microscopes.Following this, observations were made with a Scanning Electron Microscope (SEM) (Jeol JSM 6390 LV) at the Instituto de Biofísica, Universidade Federal do Rio de Janeiro and the Museu Nacional, UFRJ.A 40 Hz sonicator was used for removing the hoods from the hooks.The samples were transferred from 70% ethanol to distilled water for an hour, in order to allow the ethanol in the tissues to be replaced with water.After cutting the samples into pieces, they were sonicated in distilled water for 40 seconds, after which the resultant fragments were dehydrated with an ethanol series of 50, 70, 80, 90 and 100%, leaving 10 minutes for each concentration.The critical point was performed with a CPD 030 (Leica), and gold metallization with Balzers equipment.All specimens obtained were deposited in the polychaete collection of the Departamento de Zoologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (IBUFRJ).

RESULTS
The morphological characters that proved to be the most relevant in identifying the species described in this study were those related to the shape of the prostomium, parapodia of chaetiger 1, branchiae, the shape of the neuropodial postchaetal lamellae, and shape and distribution of the hooks (BLAKE 1983, MACIOLEK 1987, IMAJIMA 1992, EIBYE-JACOBSEN & SOARES 2000, DELGADO-BLAS 2006, WILLIAMS 2007, ZHOU et al. 2009, DELGADO-BLAS et al. 2009).Removing the hoods from the hooks before SEM observations allowed for a better visualization of the distribution and number of teeth in the hooks, and their variability among species was evaluated.

Spionidae Grube, 1850
Scolelepis Blainville, 1828 Diagnosis: Prostomium elongated with a cone-shaped or triangular anterior, extending posteriorly as a fairly conspicuous caruncle in the dorsal of the body.Occipital tentacle, present or absent.Peristomium well-developed, involving the prostomium laterally and ventrally with lateral wings.Proboscis eversible.Branchiae present from chaetiger 2 to the end of the body.Branchiae ranging from completely fused to notopodial lamellae to partially fused with the distal portion free in anteriormost segments.Simple capillary chaetae in both rami (noto and neuropodia).Median and posterior neuropodia have hooded hooks with a bluntly rounded main fang surmounted by one or two smaller apical teeth placed side by side above the main fang.Notopodia with or without hooded hooks.Pygidium thick pad shaped or with a multilobated ventral appendage; anus dorsal.(Jones, 1962) Nerinides goodbodyi Jones, 1962: 187, figs 66-68. Scolelepis goodbodyi;Delgado-Blas, 2006: 83, fig. 4 Remarks: The material, here referred to S. goodbodyi, is very similar to that originally described by JONES (1962) and DELGADO-BLAS (2006).Although differing in the presence of bilobed neuropodial postchaetal lamellae (in chaetiger 20 in the original description and between chaetigers 16-19 in our material).Previous records of this species on the Brazilian Coast were restricted to the southern coast, but now the species distribution is extended to the north-eastern coast (Ceará), filling a distribution gap given it already occurred in the Caribbean Sea.
Distribution: Pacific Ocean: Chile; Atlantic Ocean: Brazil (São Paulo and Rio de Janeiro).Remarks: The material here referred to S. lighti approximates the original description of DELGADO-BLAS (2006).However, whereas specimens described by the former author present neuropodial postchaetal lamellae notched in chaetiger 23, in our specimens it was observed in chaetiger 25.Records of this species on the Brazilian Coast was restricted to the north-eastern coast (Paraíba), now being extended to the eastern coast (Bahia).

Scolelepis andradei
Prostomium conical, elongated and posteriorly triangular, twice longer than wide (Figs 7-8).Caruncle extending posteriorly to chaetiger 2. Peristomium forming well-developed lateral wings involving the prostomium.Two pairs of brown eyes arranged in a transverse row.Central eyes rounded and lateral ones reniform.Spotted reddish pigmentation bands above eyes.Palps short (Figs 1-2), extending up to chaetiger 12 carrying two longitudinal ciliary bands.
Branchiae present from chaetiger 2, tapered and elongated with a band of cilia in the inner side, more developed in the anterior and middle part of the body, becoming smaller from chaetiger 35 (Fig. 3).Branchiae partially fused, about 1/2, to notopodial postchaetal lamellae until about chaetiger 25, thereafter, become fused only to basal lamellae (Fig. 11).
From chaetiger 31 the upper lobe becomes broader and triangular and the lower, smaller and rounded.Neuropodia of anterior chaetigers with capillary chaetae (Fig. 6) only being accompanied by limbate ones after chaetiger 20.
Neuropodial hooded hooks present from chaetiger 23 onwards with 6-8 per neuropodia, extending to the last chaetiger.Hooded hooks have one or two smaller apical teeth positioned side by side above the main fang (Figs 5-13).Notopodial hooded hooks absent.Pygidium shaped as a rounded cushion (Fig. 14).
Remarks: The material here referred to as S. andradei resembles the original description of DELGADO-BLAS et al. (2009), but differs in the emergence of the hooded hooks (from chaetiger 26 in this study, 28 in the original description).Another difference is the number of accessory teeth in the original description of S. andradei, one in the original description and one or two in specimens from Brazil.S. andradei is similar to S. goodbodyi, inhaving a well-developed peristomium and elongated branchiae with a tapered end, besides possessing uniand bidentate neuropodial hooded hooks, but lacking notopodial ones.Notwithstanding this, S. andradei differs from S. goodbodyi by having short palps and lacking gland-cells on the branchiae.Furthermore, the notopodial postchaetal lamellae of the anterior and medium body-regions are complete and with slight ripples.S. andradei is also similar to S. lighti in the  Scolelepis acuta (Treadwell, 1914) Figs 15-28 Spio acuta Treadwell, 1914: 199-201, figs 14-20. Scolelepis acuta;Delgado-Blas, 2006: 79, fig.Description: 28 complete specimens, 9-15 mm long, 0.8-1.0mm wide at chaetiger 2, with 60-80 chaetigers and 41 incomplete specimens, 4-12 mm long, 0.7-1.1 mm wide, with 46-61 chaetigers.Color in alcohol dark brown.
Prostomium anteriorly acute, posteriorly rounded, two times longer than wide .Caruncle short extending posteriorly to chaetiger 1. Peristomium short forming well-developed lateral wings involving the prostomium (Fig. 15).Eyes not visible.Palps extending up to chaetiger 11, provided with two ciliary bands.
Branchiae present from chaetiger 2, with elongated and tapered end, especially in the anterior and middle regions of the body and carrying bands of cilia in their inner side .Branchiae partially fused, by about 1/2, to notopodial postchaetal lamellae until about chaetiger 29, thereafter, become fused only in the basal lamellae (Fig. 18).
Neuropodial postchaetal lamellae rounded on anterior chaetigers, developing a slight notch in chaetiger 22, becoming deeper, dividing lamellae into separate lobes in chaetiger 25 .The lower lobe is triangular and the upper rounded with elongated tip (Fig. 26).Neuropodia of anterior chaetigers with capillaries chaetae only, accompanied by limbate after chaetiger 28.Chaetae similar in shape in both rami (noto-and neuropodia).
Neuropodial hooded hooks present from chaetiger 27, up to seven per neuropodia, extending to the last chaetiger.Hooded hooks with one or two smaller apical teeth positioned side by side above the main fang (Figs. 19,27,28).Notopodial hooded hooks absent.Pygidium shaped as a rounded cushion (Fig. 20).
Remarks: The material here referred to S. acuta fits the original description of TREADWELL (1914), as well as the redescription by DELGADO-BLAS (2006).Scolelepis acuta resembles S. squamata in the shape of the hooded hooks and the presence of small notches on neuropodial postchaetal lamellae from the median and posterior regions of the body.Such similarity led PETTIBONE (1963) and LIGHT (1977LIGHT ( , 1978) ) to consider it as a junior synonym of S. squamata.However, S. acuta differs in the, peristomium forming well-developed lateral wings, short palps and elongated branchiae with very sharp edges.S. squamata, by contrast, has theperistomium forming undeveloped lateral wings, long palps extending up to chaetiger 22, and bilobed notopodial postchaetal lamellae on the anterior chaetigers.We have also observed some similarities between S. acuta and S. goodbodyi such as the shape of the notopodial and neuropodial postchaetal lamellae of parapodia 1, the extension of the prostomium, and the shape of the neuropodial postchaetal lamellae along the body.This is the first record of the species found in the Atlantic Ocean, a pattern that could suggest that this is an invasive species (exotic), since it was found in a bay were a large port with intense international traffic (Port of Itaguaí, state of Rio de Janeiro) is located.Nevertheless, we have no further information that could corroborate this hypothesis.