Chrysopetalum occidentale Johnson, 1897

Cruz-Gómez, Christopher & Bastida-Zavala, J. Rolando, 2018, Chrysopetalids (Phyllodocida: Chrysopetalidae) from the southern Mexican Pacific, including a new species, Zootaxa 4521 (1), pp. 61-88 : 71-72

Chrysopetalum occidentale Johnson, 1897

( Figures 7 A–K, 8, 14H, 15E)

Chrysopetalum occidentale Johnson, 1897: 161 –162, pl. 5, figs.15–16; pl.6, figs. 17–19. Type locality: San Pedro Harbor, California, at 4.5 m depth.

Chrysopetalum occidentale .— Monro 1933:19 (Gorgona Island, Colombia and Galapagos); Berkeley & Berkeley 1941: 27 (south of California); Rioja, 1941: 681 (Acapulco, Guerrero, Mexico); Hartman 1961: 56 (south of California and northwest of Mexico); Reish 1963: 108 (San Quintín Bay, Baja California); Hartman 1968: 185 (south of California); Kudenov 1975: 68 (Puerto Peñasco); Fauchald 1977: 10 (Gorgona Island, Colombia); von Prahl et al. 1979: 133 (Gorgona Island, Colombia); Kudenov 1980: 92 (checklist of polychaetes from the Gulf of California); Perkins 1985: 869, figs. 3–4 (White Cove, Catalina Island and Cedros Island, Baja California Sur); Laverde-Castillo 1986: 126 (checklist of polychaetes from the Colombian Pacific Coast); Blake 1991: 83 (checklist of polychaetes from Galapagos Islands); Harris 1996: 272 (Rocas Alijos, Baja California Sur); Gómez et al. 1997: 1070 (Puerto Ángel, Tangolunda, Maguey and La Entrega beaches, Oaxaca, Mexico); López-García et al. 1997: 64 (Coiba National Park, Panama); Hernández-Alcántara & Solís-Weiss 1999: 28 (Gulf of California); Méndez 2002: 142 (Estuary Urías, Sinaloa); Aguado et al. 2003: 92 (Granito de Oro Island, Panama); Hernández-Alcántara et al. 2003: 7 (Socorro Island, Colima); Dean et al. 2012: 353 (Chatham Bay, Cocos Island, Costa Rica); Bastida-Zavala et al. 2013: 346 (checklist of species from the coast of Oaxaca); Morales-de Anda et al. 2013: 116 (checklist of polychaetes from Colima and Jalisco); Villalobos-Guerrero & Molina-Acevedo 2013: 98 (checklist of polychaetes from Sinaloa).

Material examined. Guerrero: UMAR-Poly 889, four spec. (La Ropa Beach, 17°37’37’’N, 101°32’46’’W, on rocks, 0.5 m, September 19, 2007, coll. M.S. García-Madrigal); UMAR-Poly 890, one spec. ( Ixtapa Island , 17°40’36’’N, 101°39’22’’W, on rock, 1 m, September 19, 2007, coll. M.S García-Madrigal) ; UMAR-Poly 891, seven spec. ( La Roqueta Island , Acapulco, 16°49’21’’N, 99°54’29’’W, 0–4m, September 21, 2007, coll. M.S. García-Madrigal) ; UMAR-Poly 892, two spec. ( Morro del Cerro Colorado, 17°40’47’’N, 101°30’31’’W, on stony coral, 2.7– 4 m, November 30, 2010, coll. S.D. Güenduláin) ; UMAR-Poly 893, one spec. ( Morros de Potosí , 17°38’49’’N, 101°37’44’’W, on stony coral, 6.1–11.7 m, December 3, 2010, coll. S.D. Güenduláin) ; UMAR-Poly 894, two spec. ( Manzanillo Beach , 16°50’31’’N, 99°54’37’’W, on Pocillopora damicornis , 3–6.1 m December 4, 2010, coll. S.D. Güenduláin et al.) ; Oaxaca : UMAR-Poly 895, four spec. (El Arrocito Beach, 15°45’38’’N, 96°06’00’’W, on dead coral, 3 m, May 25, 2000, coll. J.R. Bastida-Zavala) ; UMAR-Poly 896, four spec. ( Estacahuite Bay , 15°40’05’’N, 96°28’56’’W, on rocks, 3 m, April 9, 2005, coll. J.R. Bastida-Zavala) ; UMAR-Poly 897, five spec. ( Estacahuite Bay , 15°40’05’’N, 96°28’56’’W, May 12, 2005) ; UMAR-Poly 898, one spec. ( Panteón Beach , 15°39’50’’N, 96°29’43’’W, on P. damicornis , May 28, 2005) ; UMAR-Poly 899, one spec. ( Estacahuite Bay , 15°40’05’’N, 96°28’56’’W, on dead coral, November 9, 2005, coll. M.S. García-Madrigal) ; UMAR-Poly 900, six spec. ( Carrizalillo Beach , Puerto Escondido, 15°85’95’’N, 97°07’87’’W, on bivalves, August 12, 2006, coll. I. Gutiérrez & N. Pedroza) ; UMAR-Poly 901, fourteen spec. ( Estacahuite Bay , 15°40’05’’N, 96°28’56’’W, on dead coral, 3 m, August 25, 2006, coll. J.R. Bastida-Zavala) ; UMAR-Poly 902, eleven spec. ( La Tijera , 15°41’14’’N, 96°26’34’’W, on dead coral, September 12, 2006, coll. J.R. Bastida-Zavala) ; UMAR-Poly 903, one spec. ( El Faro , Chacahua Lagoon, 15°57’49’’N, 97°40’35’’W, April 13, 2007, coll. M.S. García-Madrigal) ; UMAR-Poly 904, one spec. (main pier, Puerto Ángel , 15°39’55’’N, 96°29’28’’W, on pier pilings, 0.5 m, May 20, 2007, coll. F. Cortés- Carrasco); UMAR-Poly 905, four spec. (El Arrocito Beach, 15°45’38’’N, 96°06’00’’W, on dead coral, 3 m, July 4, 2007, coll. B. Martínez) ; UMAR-Poly 906, two spec. ( Chacahua Lagoon , 15°58’07’’N, 97°41’01’’W, on sabellariid aggregation, 0.5 m, April 3, 2008, coll. P. Hernández) ; UMAR-Poly 907, three spec. ( La Tijera , 15°41’14’’N, 96°26’34’’W, on dead coral, 3 m, April 7, 2009, coll. F. Cortés-Carrasco) ; UMAR-Poly 908, one spec. ( Montosa Island , 15°45’52’’N, 96°05’04’’W, on P. damicornis , 2.7–5.8 m, February 22, 2010, coll. R. Granja-Fernández & S. D. Güenduláin) ; UMAR-Poly 909, one spec. ( Estacahuite Bay , 15°40’05’’N, 96°28’56’’W, on P. damicornis , 6.4– 9.7 m, March 26, 2010, coll. A. López-Pérez & R. Zepeta) ; UMAR-Poly 910, four spec. ( Mazunte , 15°39’42’’N, 96°33’21’’W, on P. damicornis , 7.5 m, August 11, 2010, coll. A. López-Pérez) .

Description. Based mainly on the largest complete specimen, 3.1 mm long, 0.9 mm wide, 41 segments. Body broad and rectangular, pale orange to yellow, with reddish tones at the base of neuropodia. Paleae fan yellow to golden, interlocking over dorsum. Prostomium rounded and completely visible among the first two segments. Two lateral and subulate antennae; a wide median antenna inserted between first and second pair eyes. Two pairs of reddish eyes, first pair slightly bigger than second pair, in some specimens there is a central eyespot in front of first eyes pair. Nuchal fold smaller than prostomium. Two bilobe large palps. Small and semicircular mouth fold between third and fourth segment. Eversible proboscis with two slim stylets.

Parapodium from the tenth segment. Notochaetae separated in three main groups and one subgroup ( Fig. 7A ). Lateral group inserted just below notoaciculum; comprising 1–2 slender and spine-like paleae with 3–4 ribs and one raised rib ( Fig. 7F ). As sub-unit 1, one asymmetrical palea with four ribs ( Fig. 7G ). Main group, comprising 14–20 symmetrical paleae (the length of these paleae group is variably on all segments) with 5–8 ribs ( Fig. 7H ). Median group, comprising 3–4 asymmetrical, small and curved paleae with 4–5 ribs and 0–1 raised rib, the most proximal palea is smaller than the distal palea with four ribs ( Figs 7 I–K). Neuropodium slightly small, conical shaped. Heterogomph neurochaetae composed of four groups ( Figs 7 B–E). Neurochaetiger with 1–2 superior spinigers with a partially curved and slightly serrated blade. In the first three segments neurochaetae spines and superior spinigers only. Mid-superior group consists of 4–6 falcigers, with blades as long as the superior spiniger blades. Mid-inferior group with 5 falcigers with medium length blades (3/4 of spiniger blade length) and serration basally. Inferior group with 2–3 falcigers, with short and smooth blade (1/4 of spiniger blade length). Pygidium rounded with two anal cirri.

Habitat. Intertidal to subtidal (0.5–9.7 m). The revised specimens were mostly found on dead coral, bivalves and pier pilings. This species is usually associated with bryozoans, hydrozoans, tunicates, sponges and fouling fauna ( Hartman 1961).

Distribution. California and Tropical Eastern Pacific, from northwest Mexico to Galapagos islands ( Monro 1933; Rioja 1941; Hartman 1961; Gómez et al. 1997; Dean et al. 2012) ( Fig. 8 ).

Remarks. Specimens from the southern Mexican Pacific agree with the redescription of Chrysopetalum occidentale by Perkins (1985), as well as with the description of specimens of C. occidentale from Panama by Aguado et al. (2003). The only difference among them was the number of paleae in the main group, decreasing in a latitudinal gradient. Californian specimens showed the highest number of paleae, 35–40 ( Perkins 1985); specimens from northwest Mexico showed a maximum of 30 paleae ( Perkins 1985); from southwest Mexico, specimens showed 14–20 paleae, while specimens from Coiba, Panama, showed 15–24 paleae ( Aguado et al. 2003).

Figures

FIGURE 7. Chrysopetalum occidentale. A, parapodium middle segment; B–E, neurochaetal types; F, lateral paleae; G, subunit 1 palea; H, final tip of main palea; I–K, median paleae group. Scale bars: 30 µm (BCDEH), 50 µm (FGIJK), 200 µm (A).

FIGURE 8. Historical and new records of Arichlidon watsonae n. sp., Bhawania cf. goodei, Chrysopetalum elegantoides, C. maculata and C. occidentale in the Tropical Eastern Pacific. Empty symbols indicate previous records.