Ionella agassizi Bonnier, 1900

Ionella agassizi Bonnier, 1900: 48, 222, 322–327, pls. 23, 24 (type locality: Talcahuano, Chile, infesting N. uncinata (H. Milne Edwards, 1837)) .—Nierstrasz & Brender à Brandis, 1923: 87 (list).— Caspers, 1939: 243 (list).— Holthuis, 1952: 92 (mention).— Shiino, 1964a: 27 –29, fig. 1 (Puerto Montt, Chile, infesting N. uncinata).— Danforth, 1970a: 29 (comparison with Ionella murchisoni Danforth, 1970).— Brusca, 1980: 259 (mention).— Page, 1985: 198 (mention).— Stuardo et al., 1986a: 3 (mention).— Stuardo et al., 1986b: 20 –21, 24–25, 29, figs. 2a, b, 4.10–4.15, 16–18 (Dichato and Coliuma Bay, Chile, infesting N. uncinata).— Markham, 1992a: 3, table 1 (list).— Markham, 1994: 230 (mention).— Muñoz, 1997: 36 (Dichato, Bahía Coliumo, Chile, infesting N. uncinata).—Pardo, 1998: 6, table 1 (list).—Pardo et al., 1998: 272 (mention).— Muñoz & George-Nascimento, 1999: 52 –53 (Bahía San Vicente, Ta1cahuano, Chile, infesting N. uncinata).— Trilles, 1999: 296, fig. 8.16.F (figure after Bonnier, 1900).— Astete-Espinoza & Caceres, 2000: 244 –247 (Lenga, Bahía de San Vicente, Talcahuano, Chile, infesting N. uncinata).— Markham, 2001: 198, 200 (list).— Muñoz, 2001: 756 –760 (Lenga, Bahía San Vicente, Chile, infesting N. uncinata).— McDermott, 2002: 40 (mention).— Neves et al., 2004: 209, 211 (mention).— Espinosa-Pérez & Hendrickz, 2006: 244 (list).— Muñoz & Olmos, 2007: 112, 119 (list).— Román-Contreras, 2008a: 383 (mention).— Smith et al., 2008: 231 (mention).— Castillo-Blasco et al., 2009: 715 –717 (Lenga, Chile, infesting N. uncinata).— Pardo et al., 2009: 2044, 2051–2053 (San Carlos, Valdivia, Chile, infesting N.

uncinata).— Thiel & Hinojosa, 2009: 681, 786, unnumbered figure (Chile, infesting N. uncinata).— Varisco & Vinuesa, 2011: 1684 (mention).— Stuardo & Vega, 2011: 104 (mention).— Cericola & Williams, 2015: 239 (table).

Material examined. Panama: Ovigerous female (6 mm; incomplete, tissue sampled for molecular analysis) (USNM 14376368 ex ULLZ 10202), ex right branchial chamber of Neotrypaea uncinata (6.5 mm CL, lacking gonopores) (ULLZ 10202), beach across road from NOAA / STRI lab , Panama, coll. D. L. Felder, 10 Sept 1995 .

Distribution. Pacific Panama, and coast of Chile.

Hosts. Neotrypaea uncinata (H. Milne Edwards, 1837) (type host).

Remarks. This specimen is more similar to the female illustrated by Shiino (1964a) than that illustrated by Bonnier (1900), in that the lateral plates of the pleomeres are strongly asymmetrical, though not as strongly so as in Shiino’s (1964a) specimen. This Panamanian record is a significant range extension for Ionella agassizi, which was previously known only from localities in Chile. However, the host, Neotrypaea uncinata, is known to have the broadest longitudinal range of any thalassinidean: from 34°N to 47°S (i.e., southern California to southern Chile) (Dworschak 2005). Despite the numerous records of this host from localities in Chile, Sakai (2011) inexplicably stated it was known only from the type locality. The host has been previously recorded from Panama (Ayón- Parente et al. 2014) but without this parasite.