DIAGNOSIS

Prostomium conical, extended anteriorly to long, tapering point, posteriorly triangular, raised, occipital tentacle present or absent, branchiae beginning on chaetiger 2, partially fused to notopodial postchaetal lamellae, continuing to near posterior end, neuropodial postchaetal lamellae notched or separate on posterior chaetigers, neuropodial hooded hooks present in all kinds, pygidium with oval disc or multilobed appendages.

EXAMINED MATERIAL

CIPY-POLY 926—939, 946—947, 962—964.

DESCRIPTION

Five complete specimens, 27 to 32 mm in length. Mature individuals were not observed. Specimens of S. (S.) lighti found herein are characterized by having a conical and inflated prostomium, without occipital antennae (Figure 1B,C). The caruncle is present on the prostomium, being conical and inflated, and projected posteriorly to chaetiger one (Figure 1A–C). Two pairs of small brown eyes are present, arranged in a transverse row. Lateral eyes kidney-shaped and inner ones rounded. There are big reddish spots above the eyes (Figure 1B). Narrow curved semicircular nuchal organs surround posterior margin of the prostomium. Peristomium long, distinct from chaetiger one, slightly inflated, forming well developed lateral wings (Figure 1A–C). Proboscis eversible, unarmed, with a sac-like form (Figure 1C). First chaetiger reduced, but with notopodial lamella well developed; notopodial postchaetal lamellae triangular and neuropodial postchaetal lamellae subtriangular, with capillary chaetae in both rami (Figures 1A–C & 2E). Branchiae present from chaetiger 2 to end of body (absent on last chaetigers); branchiae tapered, elongate, longest on anterior and middle part of body, partially fused to notopodial postchaetal lamellae (in the middle of branchiae). Branchiae of posterior chaetigers fused basally to lamellae (Figures 1A–C & 2). Branchiae with band of cilia along inner and outer edge, not seen with stereomicroscope. Anterior and middle notopodial postchaetal lamellae entire, with slightly ruffled edge (Figure 2). Posterior lamellae oval, with elongated pointed tip (Figure 2D–K). Low dorsal folds present on chaetigers 3–21, becoming low ciliated crests, continuing to end of body (Figure 2D–K). Neuropodial postchaetal lamellae on chaetiger 1 ellyptical (Figure 2D). Lamellae on chaetigers 2 oval (Figure 2E); on the following chaetigers the lamellae are rounded, with a slight notch in chaetigers 21–25 (Figure 2J,K). This notch becomes deeper posteriorly, dividing the lamellae into two lobes in chaetigers 22–29 (Figure 2K). On the following chaetigers the lower lobe remains triangular, being located ventrally to the hooks. Posterior hooks accompanied by two small, broad, limbate, finely tapered chaetae. Hooded hooks with two small apical teeth surmounting large main tooth and with long, curved, shaft (Figure 2B,C). Neuropodial hooded hooks beginning generally from chaetigers 10 to 14, numbering seven to nine per fascicle, but sometimes they occur from chaetigers 23 to 24, numbering four to five per fascicle. The variation in the starting point of the neuropodial hooks was directly related to body size. In larger body lengths, the neuropodial hooks usually begin in more posterior segments. Sabre chaetae absent. Notopodial capillary chaetae similar in morphology to those of the neuropodium, although more elongate, arranged in two rows, those of posterior row longest (Figure 2A). Notopodial hooded hooks absent, even in the five complete specimens with up to 72 chaetigers. Most specimens examined were broken in the middle of the body. The relatively small number of the chaetigers could be the reason for the absence of notopodial hooded hooks. Pygidium with ventral cushion (Figure 1D,E).

Fig. 1

Scolelepis (S.) lighti. (A) CIPY-POLY 928 in lateral view, anterior and median regions; (B) CIPY-POLY 964 in dorsal view; (C) CIPY-POLY 963 in lateral view of anterior region; (D) CIPY-POLY 928 in ventral view of posterior region showing the ventral cushion; (E) CIPY-POLY 928 in lateral view of posterior region. Scale bars: A,B, 1 mm; C,D, 0.5 mm; E, 1 mm.

Fig. 2

Scolelepis (S.) lighti Delgado-Blas, Reference Delgado-Blas2006. (A) Capillary chaeta; (B) tridentate hooks; (C) detail of tridentate hooks; (D) chaetiger 1; (E) chaetiger 2; (F) chaetiger 6; (G) chaetiger 7; (H) chaetiger 13; (I) chaetiger 20; (J) chaetiger 21; (K) chaetiger 22. Scale bars: A, 0.58 mm; B, 1.45 mm; C, 0.58 mm; D–K, 2.9 mm.

REMARKS

No Scolelepis species have been published before in the north-east region of Brazil. The material examined is similar to the descriptions of S. (S.) chilensis Hartman-Schröder, 1962, and of S. (S.) lighti Delgado-Blas, Reference Delgado-Blas2006, because both species have a similar form of prostomium, peristomium, organization of eyes, form and organization of lamellae, and form of pygidium. The illustrations provided by Hartmann-Schröder in 1962 and Blake (Reference Blake1983) show that the notopodial lamellae are less fused to the branchiae than in S. (S.) lighti. Therefore only the examination of type series using the same methodology could solve the question of a possible synonymy between the two species. Although Delgado-Blas (Reference Delgado-Blas2006) described S. (S.) lighti as having tridentate hooks, the apical teeth were not well illustrated. Studies of intraspecific and interspecific variation of S. (S.) chilensis and S. (S.) lighti have to be carried out to comprehend this characteristic. Consequently, the illustrations of hooded hooks presented in the description of S. (S.) chilensis and S. (S.) lighti are very similar, but no observations under a scanning electron microscope have been done to confirm that specimens from both species have tridentate hooded hooks.

Blake (Reference Blake1983) re-examined the type specimens of S. (S.) chilensis and considered the apical teeth of the hooded hooks fused by a ridge as being another distinguishing characteristic of S. (S.) chilensis, whereas S. (S.) squamata is characterized by having unidentate, bidentate and tridentate hooded hooks with distinct apical teeth. The specimens examined by us show tridentate hooded hooks with two distinct apical teeth. These characteristics reinforce the difference between S. (S.) chilensis and S. (S.) lighti. On the other hand, this character was not clearly illustrated in the type material of S. (S.) lighti.

Delgado-Blas (Reference Delgado-Blas2006) shows that S. (S.) lighti is most similar to S. (S.) squamata Müller, 1806, and that it differs in the form of the anterior and middle notopodial lamellae, the shape of the branchiae, and for having only tridentate hooded hooks. Another species was found along the Brazilian coast, S. (S.) goodbodyi Jones, 1962. This species could be easily distinguished from S. (S.) lighti and S. (S.) squamata by the presence of bands of pigmented cells in the first chaetigers, by the inflated shape of the peristomium, the lamellate form of the parapodia, and the segment in which neuropodial hooks begin (on chaetigers 10–14 in S. (S.) lighti, and on chaetigers 43–50 in S. (S.) squamata).

Recently, some specimens have been identified as S. (S.) cf. chilensis for the south and south-east of Brazil by Maria Emilia Diez and Vasily Radashesvky (personal communication), but no description or illustration has been provided for this material up to the present time.

GEOGRAPHICAL DISTRIBUTION

Scolelepis (S.) lighti is now distributed from the Gulf of Mexico (Tamaulipas, Tabasco, Quintana Roo) to Brazil (State of Paraíba, coast of João Pessoa city).