Phragmatopoma peruensis Hartman, 1944

Figure 7 A–M

Phragmatopoma peruensis Hartman, 1944: 353–354, pl. 37, figs. 84–85, pl. 39, fig. 99, pl. 41, fig. 104. Type locality: Salaverry, Peru, intertidal.

Phragmatopoma peruensis .—Hartman 1959: 474 (Peru, catalog of the Polychaeta); Achari 1974: 451 (world comparison of sabellariids); Lana & Bremec 1994: 211, fig. 1d (checklist of polychaetes from South America and identification key).

Phragmatopoma virgini (not Kinberg, 1867).— Kirtley 1994: 37–40, figs. 2.4.4 (Peru).

Material examined. Three specimens. Peru: UMAR-Poly-980 (Puerto Eten, Lambayeque, 6°55’46”S, 79°52’13”W, on rocks between algae and mollusk, February 16, 2013, coll. I. Carmona) .

Description. Color pattern of preserved specimens. Body pale yellow (Fig. 7A). Outer paleae with blade and handle amber; median plume translucent (Fig. 7 D–E). Middle paleae dark brown to light yellow toward the tip (Fig. 7 G–H). Inner paleae dark yellow (Fig. 7I). Opercular papillae yellowish. Median ridge with brown eyespots (Fig. 7C). Tentacles brown (Fig. 7A, C). Building organ pale yellow (Fig. 7C). Branchiae dark brown (Fig. 7A). Parathoracic chaetae yellowish (Fig. 7F, J–K). Abdominal neuropodia brown purple. Abdominal neurochaetae and uncini translucent (Fig. 7 L–M). Caudal peduncle dark brown to light brown toward distal part (Fig. 7A).

Body. Complete specimen of 17 mm total length; parathoracic region 3 mm wide; 36 abdominal segments; caudal peduncle 3.7 mm long (Fig. 7A).

Operculum. Opercular crown and opercular stalk completely fused. Opercular crown conical and sub-circular, slightly protruding in lateral view (Fig. 7 A–B). Three rows of paleae, only two visible: 62 outer paleae, 30 middle and inner paleae (Fig. 7 A–B). Outer paleae geniculate with a pair of isodont teeth slightly curved; flat blade twice as long as than wide, with dorsal surface smooth and ventral one serrated; median plume short, ¼ as long as blade, sub-quadrangular, twice longer than wide, smooth and flat (Fig. 7D). Middle paleae strongly geniculate with straight peak, slightly concave, rough surface with transversal thecae; sub-quadrangular nape, straight, margin serrated, wider than peak, 1/3 as long as peak; chin slightly wider than long, margin smooth; blunt tip slightly falcate, with smooth margin (Fig. 7 G–H). Middle paleae of different sizes depending on their position in the crown, larger dorsally and decreasing in size ventrally. Inner paleae strongly geniculate with serrated peak straight, almost eight times longer than wide; nape smooth; tip without apparent filaments (Fig. 7I). Papillae small and oval. Oral tentacles unbranched. Median ridge unclear, tissue of opercular stalk damaged; marginal eyespots present, ¼ as long as opercular stalk (Fig. 7C). Median organ absent. Building organ’U’- shaped (Fig. 7C).

Thorax. Chaetiger 1 with a pair of neuropodial cirrus, bipinnate chaetae (Fig. 7C). Chaetiger 2 with three pairs of conical cirrus, bipinnate chaetae and a pair of branchiae.

Parathorax. Three parathoracic segments (Fig. 7A). Chaetigers with a pair of branchiae. Notopodia with lanceolate chaetae interspersed with small capillary chaetae (Fig. 7 J–K). Neuropodia with lanceolate chaetae interspersed with small lanceolate chaetae (Fig. 7F); neurochaetae thinner than notochaetae.

Abdomen. Segments with a pair of branchiae decreasing in size towards posterior segments; absent in the last four chaetigers (Fig. 7A). Neurochaetae verticillate of different length (Fig. 7M). Notopodia with a series of uncini with seven pairs of teeth (Fig. 7L).

Caudal region. Caudal peduncle elastic, rough, with annulated appearance but without segmentation, and as long as 11 posterior segments (Fig. 7A).

Tubes. Lost.

Variation. Body measurements varied from 13–17 mm total length and parathoracic region 2.5–3 mm wide (n= 3 spec.). The abdominal segments varied from 30–36. Two specimens with almost all outer paleae with lacerate plume, possibility broke, with rectangular and wide sections (Fig. 7E).

Habitat. Intertidal, template waters.

Distribution. Hartman (1944) described Phragmatopoma peruensis from Salaverry, Peru. These specimens were collected in Puerto Eten, Lambayeque, Peru, expanding its distribution ~180 kilometers to south (Fig. 13).

Remarks. The diagnostic features of P. peruensis are the lack of chaetae in the first segment, outer paleae with flat plume and rounded edge, and the length in adult individuals less than 10 mm. My specimens have chaetae in the first segment and are larger than 10 mm, but the shape of paleae is the same. Kirtley (1994) revised the type material of P. peruensis and he concluded P. virgini, a species of Chile, and P. peruensis were synonyms.

Our specimens identified as P. peruensis have outer paleae with blade curved (Fig. 7 D–E) and not straight and flat as those in P. virgini (Fig. 6I); lateral teeth slightly curved (Fig. 7D) and not straight (Fig. 6I, M); and median plume oval and smooth, absent in Johansson’s (1926) and Hartman’s (1944, Fig. 6I) specimens, but possibly similar to the ones revised by Kirtley (1994, Fig. 6J). The middle paleae of P. peruensis and P. virgini differed principally by the nape and tip morphology; straight nape and slightly curved tip in P. peruensis (Fig. 6L, 7G), and straight (Hartman 1944) or decurrent nape (Kirtley 1994) with curved tip in P. virgini (Fig. 6 G–H, K). The number of uncini teeth varied in both species, being seven pairs in P. peruensis (Fig. 7L), not six pairs as in P. virgini . The distribution of both species also is an important factor; P. peruensis is a tropical species, while P. virgini is a polar species. So, the synonymy cannot be sustained and consequently, P. peruensis must be regarded as a distinct species.

Phragmatopoma peruensis is similar to P. moerchi in the presence of translucent median plume; oval and smooth in P. peruensis (Fig. 6N, 7D), and rectangular and lacerate in P. moerchi (Fig. 2B). This characteristic could be similar in both species as some specimens of P. peruensis have median plume lacerated (possibly due to abrasion) (Fig. 7E); however, in P. peruensis the outer paleae have isondont teeth, and not heterodont as P. moerchi . Also, in P. peruensis, the middle paleae have a sub-quadrangular nape, 1/3 as long as peak, with sharp tip slightly curved (Fig. 6L, 7G), in contrast with sub-circular (Hartman 1944) or sub-quadrangular nape (Johansson 1926), ¼ as long as peak, with sharp tip falcate (Johansson 1926) or slightly elevated (Hartman, 1944) present in P. moerchi (Fig. 6O). The inner paleae are thinner in P. moerchi (Fig. 6P), 16–17 times longer than wide (Johansson 1926, Hartman 1944), than in P. peruensis, eight times than longer than wide (Fig. 7I). As in the case of P. virgini, the re-description of P. moerchi is necessary to compare its morphology with that of the other species of Phragmatopoma .