Chrysopetalum maculatum

Description. Based on the only specimen found: complete with 32 segments. TL = 2.7 mm, TW = 0.4 mm. Body long, broad, tapered posteriorly (Fig. 21 A). Body pale orange. Paleae fan bright yellow, slightly imbricated dorsally. Prostomium visible between the first two segments. Lateral antennae short, inserted on the antero-ventral prostomial margin, median antenna short, half of lateral ones, inserted in front of the first pair of eyes. Eyes red-violet, two pairs. Nuchal organ, small, not covering the prostomium (Fig. 21 B). Palps long, cylindrical, visible in dorsal view. Mouth fold large, placed between segment 3 and 4. Pharynx eversible, not exposed, stylets thick. Parapodium from segment 27, notochaetae in three main groups (Fig. 21 D). Notochaetae: lateral group inserted below notaciculum, 3 – 4 paleae, narrow and asymmetrical, with 1 – 2 internal ribs (Fig. 21 E); subunit 1, 1 paleae, broader and asymmetrical, with 5 internal ribs (Fig. 21 F). Main group, 20 – 24 paleae; lateral-most paleae, asymmetrical, with (8) 10 – 13; mid-most paleae, symmetrical, with 10 – 11 internal ribs and 0 – 1 raised ribs; midline-most paleae, asymmetrical, with (8) 10 – 12 (Fig. 21 G). Median group, 3 – 4 paleae, shorter, curved and asymmetrical, with 4 – 8 internal ribs and 0 – 1 raised rib (Fig. 21 H). All paleal groups with margins finely serrated, dorsal paleal surface ornamented with raised tubercles. Neuropodium conical, longer than notopodium. Neurochaetae: unit 1, 2 – 5 falcigers, blades straight and long, 11 – 12 times longer than wide (Fig. 21 I). Unit 2, 6 – 8 falcigers, blades straight and medium-sized, 3 – 4 times longer than wide. Unit 3, 5 – 6 falcigers, blades straight and medium-sized, 6 – 7 times longer than wide (Fig. 21 K). Unit 4, 2 – 3 falcigers, blades straight and short, 2 – 3 times longer than wide (Fig. 21 L). Pygidium rounded with two anal cirri (Fig. 21 C). Oocytes not seen. Habitat. Intertidal to subtidal (0 – 10 m). The sole specimen examined was possibly obtained from dead coral (Bastida-Zavala Pers. Comm. 2017). Previously, specimens of C. maculatum were collected in rocks, dead coral, and coarse sand (Aguado et al. 2003; Cruz-Gómez & Bastida-Zavala 2018).

Figs 21, 26

Remarks. Recently, the suffix of the epithet was modified by Read (2018) to match with the neuter gender of the genus (ICZN 1999, Art. 31.2). The species is easily distinguishable among Chrysopetalum due to broad main paleae.

Distribution. From La Paz Bay, Baja California Sur to Roca Bajo Mali, Panamá (Fig. 26).

Type locality: Bajo Mali Rock (7 º 39´00 ” N, 81 º 41´40 ” W), Coiba Island, Panamá, on coarse sand at 0 – 4 m (Aguado et al. 2003). Material exmined. Baja California Sur: UMAR-Poly 942, La Paz Bay, coll. RBZ, no further data.