Paleaequor psamathe Watson Russell, 1986

Cruz-Gómez, Christopher, 2021, A new genus and seven new species of chrysopetalids (Annelida, Chrysopetalidae) from the Tropical Eastern Pacific, Zootaxa 5068 (1), pp. 1-59 : 27

Paleaequor psamathe Watson Russell, 1986

Figs 13 , 26

Paleaequor psamathe Watson Russell, 1986: 168–170 , Figs 22–24 .

Type locality: Punta Pelícano, Sonora, Gulf of California, at 13 m ( Watson Russell 1986) .

Material examined. Seventy-one specimens. Baja California: ECOSUR- 2982, 3 spec. Bahía de Los Ángeles, May 25, 1986, coll. SSV. Baja California Sur: ECOSUR-2113 , 2 spec. Bahía Concepción , June 17, 1980, coll. RR; ECOSUR-2114 , 3 spec. Bahía Concepción , May 6, 1981, coll. HL; ECOSUR-2112 , 3 spec. El Coyote, Bahía Concepción , April 8, 1982, on coral, coll. EGV; UANL 003670 , Bahía Concepción , July 18, 1985, coll. ALG; UANL 0047 , Bahía Concepción , July 20, 1985, coll. ALG; UANL 0048 , 3 spec. Bahía Concepción , July 20, 1985, coll. SSV; ECOSUR-2976 , El Presidente Beach, La Paz Bay , October 10, 1987, coll. SSV; UMAR-Poly 955, El Presidente Beach , April 20, 1988, col. RBZ; UMAR-Poly 956, 4 spec. El Caimancito Beach , April 20, 1988, coll. RBZ; UMAR-Poly 957, Armenta, Bahía Concepción, on Sargassum sp. , coll. RBZ; ECOSUR-3005 , El Caimancito Beach ,, La Paz Bay , February 29, 2004; ECOSUR-2977 , 10 spec. La Paz Bay , 0.7 m , March 1, 2004; ECOSUR- 2989 , 2 spec. La Paz Bay , 1 m , March 2, 2004; ECOSUR-3068 , La Marina, 24º09.319´N, 110º19.630´W, La Paz Bay , on pier piles, 0.5 m, 1 spec. in 250 cm 2 , August 14, 2011, coll. MAC & IRS; ECOSUR-3071 , 3 spec. La Marina, 24º09.319´N, 110º19.630´W, La Paz Bay , on pier piles, 0.5 m, 3 spec. in 250 cm 2 , August 14, 2011, coll. TVG & ADL. Nayarit: ECOSUR-2995 , 5 spec. Punta Borrego , on bivalve, 1 m , November 23, 2004; ECOSUR-P3002, 3 spec. Punta Borrego , on bivalve, 2 m , November 24, 2004; ECOSUR-3212 , La Cruz , on rocks, 0.3 m , November 26, 2004, coll. BY & PSS; ECOSUR-2938 , 7 spec. La Manzanilla , on rock with sponge, 2 m , November 29, 2004, coll. BY & PSS. Jalisco: ECOSUR-2979 , 2 spec. Melaque , on rocks with sand, 1 m , December 1, 2004, coll. BY & PSS; ECOSUR-2978 , 2 spec. andador, Melaque , on rocks, 3 m , December 2, 2004, coll. BY & PSS; ECOSUR-2980 , 2 spec. San Pedro Channel , rock with coral, 5 m , June 26, 2013, coll. BY. Michoacán: UMAR-Poly 958 Caleta de Campos , December 17, 1994, coll. RBZ; UMAR-Poly 959, 6 spec. Caleta de Campos , December 20, 1998, coll. RBZ. Perú: One spec. UMAR-Poly 960, Albacora, Tumbes, 3°64´78”S, 80°74´34”O, on mud, 8 m , 2012; UMAR- Poly 961, Corvina , Tumbes, 3°62´76”S, 80°70´76”O, on mud, 15 m , 2012.

Description. Based on the best-preserved specimen (ECOSUR-3068): complete with 104 segments. TL= 7.1 mm, TW= 1.3 mm. Body long, slender, tapered posteriorly ( Fig. 13A ). Body pale orange to bright orange. Paleae fan translucent, imbricated dorsally.

Prostomium visible among the first four segments. Lateral antennae short, inserted on the antero-ventral prostomial margin, median antenna slightly short than lateral ones, inserted in front of the first pair of eyes. Eyes redviolet, two pairs. Nuchal organ, small, partially covering the prostomium ( Fig. 13B ). Palps long, cylindrical, visible in ventral view. Mouth fold small, placed between segment 2 and 3. Pharynx eversible, not exposed, stylets thick.

Parapodium from segment 15, notochaetae in three main groups (13E). Notochaetae: lateral group inserted below notaciculum, 3–5 paleae, slender and symmetrical, with 4–7 ribs ( Fig. 13F ); subunit 1, two kinds of paleae: subunit 1a, broad and symmetrical, with 8 internal ribs and serrated margins; subunit 1b, larger, broad and symmetrical, with 14 internal ribs ( Fig. 13G ). Main group, 15–17 paleae, broad and symmetrical, with 17–22 internal ribs and (3) 4–6 raised ribs ( Fig. 13H ). Median group, 3 paleae, shorter, broad and symmetrical, with 14–22 internal ribs and (0) 3–5 raised ribs ( Fig. 13I ).

Neuropodium conical, slightly shorter than notopodium. Neurochaetae: unit 1, 1–2 superior spinigers, blades curved and long, 20 times longer than wide ( Fig. 13J ). Unit 2, 3–4 falcigers, blades curved and medium-sized, 5–6 times longer than wide ( Fig. 13K ). Unit 3, 4–6 falcigers, blades curved and medium-sized, 2–4 times longer than wide ( Fig.13L–M ). Unit 4, 2–3 falcigers, blades curved and short, 2–3 times longer than wide ( Fig. 13N ). Pygidium rounded with two anal cirri, and a large ventral cone ( Fig. 13C ). Oocyte size: 15–25 µm (n=6) ( Fig. 13D ).

Habitat. Intertidal to subtidal (0.5– 20 m). Specimens of P. psamathe were collected on rock, sand, mud, as epibiont of bivalves, coral, and among the fouling communities. This species has been also recorded as epibiont of algae, sponges, and in tubes of terebellids and chaetopterids ( Watson Russell 1986; Cruz-Gómez & Bastida-Zavala 2018).

Distribution. From Bahía de los Ángeles, Baja California to Albacora, Perú ( Fig. 26 ).

Remarks. Specimens from México and Perú shared the same features and agree with the description and illustrations by Watson Russell (1986).

Figures

FIGURE 13. Paleaequor psamathe Watson Russell, 1986, non-type specimen (ECOSUR-3068). A) Complete body. B) Drawing of prostomium, ventral view. C) Drawing of pygidium, ventral view. D) Oocyte. E) Parapodium from segment 15. F) Lateral paleae. G) Subunit 1, two kinds of paleae. H) Main paleae. I) Median paleae. J) Unit 1. K) Unit 2. L) Unit 3. M–N) Unit 4. Scales: 10 µm (JKLMN), 50 µm (BCFGHI), 200 µm (E), 2 mm (A).

FIGURE 22. Chrysopetalum occidentale Johnson, 1897, non-type specimen (ECOSUR-2111). A) Complete fragmented body. B) Drawing of prostomium, dorsal view. C) Drawing of pygidium, ventral view. D) Ooocyte. E) Parapodium from segment 30. F) Lateral paleae. G) Subunit 1. H) Main paleae. I–K) Median paleae. L) Unit 1. M) Unit 2. N) Unit 3. O) Unit 4. Scales: 20 µm (LMNO), 50 µm (CDFGHIJK), 100 µm (B), 200 µm (E), 1 mm (A).

FIGURE 23. Chrysopetalum mexicanum n. sp., holotype (ECOSUR-270).A) Complete fragmented body. B) Drawing of prostomium, dorsal view. C) Drawing od pygidium, ventral view. D) Oocyte. E) Parapodium from segment 27. F) Lateral palea. G) Main palea, lateral-most. H) Main palea, mid-most. I) Main palea, midline-most. J–K) Median paleae. L) Unit 1. Scales: 10 µm (LMNO), 20 µm (FGHIJK), 50 µm (CD), 100 µm (BE), 1 mm (A).

FIGURE 24. Chrysopetalum tovarae n. sp., holotype (ECOSUR-273). A) Complete fragmented body. B) Drawing of prostomium, dorsal view. C) Drawing of pygidium, ventral view. D) Oocyte. E) Parapodium from segment 20. F) Lateral palea. G) Main palea, lateral-most. H) Main palea, mid-most. I) Main palea, midline-most. J) Median paleae. K–L) Unit 1. M) Unit 2. N) Unit 3. O) Unit 4. Scales: 10 µm (KLMNO), 20 µm (FGHIJ), 50 µm (CD), 100 µm (BE), 1 mm (A).

FIGURE 26. Previous and new records of chrysopetalids in the Tropical Eastern Pacific. Empty symbols indicate historic records.